Title of Invention	A METHOD AND APPARATUS FOR SORTING THE FIBERS OF A FIBER STRUCTURE
Abstract	A method for sorting the fibers of a fiber structure which is supplied to a fiber sorting device, characterized in that it comprises the steps of nipping the fiber structure transversally to its conveying direction in a defmite distance from the effective end of the fiber strand; exposing the free end projecting beyond the clamping point with an air flow; extracting and removing from the free end, any non-nipped components such as short fibers, neps, dust etc.

Title of Invention

A METHOD AND APPARATUS FOR SORTING THE FIBERS OF A FIBER STRUCTURE

Abstract

A method for sorting the fibers of a fiber structure which is supplied to a fiber sorting device, characterized in that it comprises the steps of nipping the fiber structure transversally to its conveying direction in a defmite distance from the effective end of the fiber strand; exposing the free end projecting beyond the clamping point with an air flow; extracting and removing from the free end, any non-nipped components such as short fibers, neps, dust etc.

Full Text	The invention relates to a method and an apparatus to perform the method for sorting the fibers of a fiber structure which is supplied by feeding means to a fiber sorting device. in order remove short fibers, neps, dirt and other components from a fiber mixture it is known to supply the fiber material in the form of lap rolls to the combing machines for combing. In this process, the end of the web is nipped by a nipper and the end projecting beyond the nip point of the nipper is mechanically combed out by a combing unit of a circular comb. Damage to the fibers may occur under certain circumstances during this combing process. The disadvantage in the known methods is also the discontinuous mode of operation, whereby it is necessary to reverse large masses during the working cycle. An apparatus was therefore proposed in the published PCT application WO 98/04765 to _ perform the separation of short fibers, dirt and other components by means of an air flow, with the air flow being substantially produced in the conveying direction of a nonwoven. During this process the nonwoven guided through an air conduit is subjected at two places to a holding force, so that it is ensured that the long fibers to be gained are not carried off by the air flow. A certain separating effect could already be achieved with this device. It was not yet satisfactory, however, because it was difficult to purposefully extract all short fibers from the endless nonwoven with"the air stream. In a further, still unpublished Swiss patent application of the applicant with the application number CH-254/98 of 3 February 1998, it was proposed in this system for the purpose of increasing the separating effect to prepare the fiber material first in a respective manner before it reaches the separating conduit. It was proposed therein to prepare the fiber material into individual and adjacent, longitudinally arranged single fibers before it is subjected to the air flow. It was noticed that an improved separating effect was produced and that fewer long fibers (batch-fibers) were contained in the waste. In order to further increase the separating effect it was proposed to guide the thus prepared nonwoven over several successively switched separating stages. Although it was managed to improve the separating effect and the separating quality with this device, they were still not yet adequate. The goal of achieving the degree and quality of separation of a conventional combing machine could not yet be achieved with this device. Based on the mentioned devices and state of the art the invention is now based on the object of providing a method and an apparatus by which a higher degree of separation and a higher quality of separation can be achieved as compared to the known pneumatic methods. This object is achieved, on the one hand, by a method in which the fiber structure is nipped transversally to its direction of conveyance and the free end projecting from the nipped position is subjected to an air flow which is capable of extracting and carrying off any undamped components (such as short fibers, neps, dust, etc.) from the free end. In this proposed method the selection process (sorting process) is performed with air as in a mechanical separating process in the combing machine on an open end of the fiber ■ structure (lap, nonwoven, fiber structure, etc.). The air flow produced in the direction towards the free end of the fiber structure allows blowing out and carrying off undamped components. The intensity of the air flow depends on the size of the supplied fiber mass. In order to improve the separating effect it is proposed that the fiber structure, prior to reaching the sorting device, is broken down into individual fiber packages with single fibers which are substantially stretched in the longitudinal direction and are in approximately parallel alignment to one another. This allows exercising a purposeful nipping effect on the now present, longitudinally stretched fibers, which ensures that only very few long fibers are entrained during the sorting process. in order to produce the fiber packages it is proposed that fiber packages are discontinuously produced from the free end of the fiber structure by way of a respective draw-off element. Such a preparation of the fibers into thin fiber packages or tufts is already known from the principle of the fibroliner. According to this principle the fiber packages are arranged at ends, with the short fibers being disposed in the forward end (nip line) of the fiber packages. With a fiber mass which is prepared in such a way it is possible to perform a purposeful nipping effect in the subsequent selection process (sorting process) in order to remove the short fibers disposed in the head end. It is proposed further that, as seen in the conveying direction of the fiber package, the fiber package is nipped during the sorting process at a predetermined distance to its front end which is subject to the air flow. Said front distance to the head end of the fiber package can be compared with the setting distance of the card. All short fibers which are disposed in the head zone and are not held by the nip are removed upon application of the air flow. It is preferably proposed that the air flow, as seen from the nip point, is directed in the direction towards the free end of the fiber structure or fiber package. The air flow can be produced by a source of pressure below or above atmospheric. It is proposed further that after the sorting process the nip force at the nip point is released and the sorted fiber material is transferred to a downstream sliver-forming unit for forming the sliver. The formation of the sliver can be produced by superimposing layers of the sorted fiber packages. This method corresponds to the piecing process in conventional combing machines. A method is further proposed, with at least two fiber structures being supplied to the fiber sorting device simultaneously and the ends of the fiber structures being subjected to a common air flow. It is advantageous in this respect when the ends of the individual fiber structures are joined together and the air is blown between the ends of the fiber structures, starting from the zone of their nip points. This allows blowing compressed air in a purposeful manner into the joined ends in order to grasp and separate all short fibers which are disposed in the interior of the ends and are not nipped in any way. In order to intensify the separating effect it is proposed that at least one additional compressed air flow is produced downstream of the respective nip point in the direction towards the free end and onto the outside surfaces of the joined ends of the fiber structures. It is possible to apply the air pulses thus produced in different time intervals. The invention is also achieved by an apparatus, with nip apparatuses being provided which nip the fiber structure at a distance from its free end and means are present which produce an air flow from the nip point to the free end of the fiber structure. In order to prepare the fiber structure it is proposed that means are provided in order to open the fiber structure into individual fiber packages with single fibers which are substantially stretched in the longitudinal direction and are aligned parallel to one another, which fiber structure is supplied step-by-step by the feeding means, and with means for transferring the fiber packages to a downstream sorting device. It is important in this respect that the structure of the formed fiber packages or the longitudinal alignment of the fibers is maintained during the transfer to the actual sorting device. It is proposed that the feeding means are formed by a drafting arrangement and the means for producing the individual fiber packages consist of a rotatably held roller which forms a nip point together with a rotatably held suction drum which is opposite of the delivery place of the drafting arrangement. Preferably, the drafting arrangement can be an apron drafting system. In order to perform a purposeful draw-off process of the fiber package and to precisely guide the fiber package after the draw-off process it is proposed that the draw-off roller is enclosed with a revolvingly held apron over a partial section of its circumference, at least in the zone of the nip point. It is advantageous in this respect if the apron rests after the nip point on the circumference of the suction drum over a partial section of the same. This ensures the ideal guidance of the formed fiber package. This means that the fiber package is guided in a forced way, thus ensuring that the individual fibers retain their position when transported off. In order to intensify the nipping effect during the draw-off process of the fiber package from the end of the fiber structure it is proposed that the suction drum is provided with elevations which are distributed in a spaced manner on the circumference of the same. These elevations form in combination with the apron which is placed around the draw-off roller a secure nip point and ensure a secure entrainment of the fibers held in the nip point. The elevations can be made of elastic material in order to produce a careful nip. It is also possible to provide the draw-off roller co-operating with the suction drum with an elastic cover. A further embodiment is possible in that the elevations on the suction drum are omitted and are applied on the revolving apron instead. It only needs to be ensured that in the take-off zone between the suction drum and the draw-off roller it is possible to apply a purposeful nip force in order to pull out the fiber packages from the end of the supplied fiber structure. Moreover, the secure further transport without causing any compressions must be ensured. The distance between the elevations fastened between the suction drum and the apron must be larger than the length of the longest fiber in the fiber structure. In order to support the guidance of the drawn fiber packages it would be possible to apply a negative pressure in the interior of the suction drum in the draw-off zone, so that the ends will securely come to rest on the suction drum. It is further proposed that a rotatably held separating drum is assigned in an axially parallel manner to the suction drum, which separating drum is provided with several radially outwardly facing suction slots, with the suction slots corresponding with a negative pressure chamber in the position of the smallest distance to the outside circumference of the suction drum, which negative pressure chamber is fixedly arranged in the separating drum and is provided with a suction means. The distance between the outside jacket of the suction drum and the separating drum can be chosen in such a way that at the time of applying a negative pressure a nipping effect is exercised on the fiber package in the respectively positioned suction slot. The nip line thus produced is located at a distance from the front end of the fiber package, as a result of which all non-nipped components (such as short fibers) are carried off into the suction slot by the produced air stream. In order to achieve a precise and defined nip point it is proposed that, as seen in the direction of rotation of the separating drum, elastic elevations on the outside circumference of the separating drum adjacent to the respective opening of the suction slots, which elevations exercise a nipping effect with the outside circumference of the suction drum at the position of the smallest distance between the suction drum and the separating drum. In this embodiment there is a distance between the outside jacket of the suction drum and the separating drum, with the distance being smaller than the height of the elastic elevation in the radial direction of the separating drum. This ensures that the elastic elevation deforms in this zone and can thus exert a pressure force on the fiber package. For the purpose of a secure transfer of the fiber packages it is proposed that means are provided to produce a negative pressure in the interior of the suction drum at least in a partial zone between the region where the apron rests on the outside circumference of the suction drum and the transfer zone next to the separating drum. The negative pressure only needs to be large enough, so that the position and the alignment of the single fibers in the fiber package do not change during the transport to the transfer position. It can be partly possible however to remove short components such as dust from the fiber mixture in this zone by the application of the negative pressure. In order to remove the selected fiber material it is proposed that a rotatably held doffer is provided axially parallel to the separating drum, which doffer touches the outside circumference of the separating drum. The doffer can be provided with a clothing on its outside circumference. In order to securely introduce the forward ends of the fiber packages into the respective suction slot for the selection process it is possible to provide an excess pressure source in the interior of the suction drum in order to produce a compressed air flow in the direction towards the suction slot. A further embodiment of the invention is obtained when the fiber sorting device is supplied with at least two fiber structures by means of conveying means and movably held nipping elements are provided for each fiber structure, which elements cooperate with a common guide element. It is possible to supply also more than two fiber structures to the fiber sorting device when providing a respective arrangement of the nipping device. It would also be possible to guide the fiber structures before the nip point by a drafting device in order to prepare the same for the subsequent sorting process. It is proposed as a further embodiment that at least one air nozzle is arranged whose opening, as seen in the conveying direction of the fiber structures, opens downstream of and*between the nip points and is connected with a compressed air source. The air nozzle extends over the entire width of the supplied fiber structures. A variant is also possible where several adjacent fiber structures (e.g. slivers) are supplied to the nip point. The term "fiber structure" can comprise for example a nonwoven, a lap, a sliver or the like. The preferable further developments as explained below can also relate to an embodiment where only a single fiber structure is supplied to the nip elements (this means without joining the ends of at least two fiber structures). Concerning the supply of several fiber structures it is proposed further that the guide element is provided with opposite guide troughs into which the conveying roller, which is used as the conveying means, immerses. In order to intensify the separating effect it is proposed further that air nozzles are integrated in the zone and downstream of the nip surfaces of the nip elements in the nip elements and are in connection with a compressed air source. This also allows pressurizing the end from the side with compressed air in the longitudinal direction, with said end projecting beyond the nip point. The separating effect is thus intensified. In order to draw off a fiber package from the selected end of the fiber structure it is proposed that a pair of rollers is arranged downstream of the nip elements which form a nip line. it is possible to provide the feeding devices displaceably in the direction towards the pair of rollers when the nip elements are released, so that the forward end of the fiber structure can be grasped by the nip line of the downstream pair of rollers. This draw-off process can be regarded as being equivalent to the detaching process of the combed fiber tuft in the combing machine. In order to discharge the waste material which is released during the blowing process of the free end of the fiber structure it is proposed that at least one of the rollers of the pair of rollers is provided as a hollow cylinder with outwardly facing openings, with the hollow chamber being connected with a negative pressure means. The outwardly facing openings are only present on a partial range of the circumference of the hollow cylinder, so that during the detaching process the closed nip line is present in the pair of rollers on the one hand and a suction of the drawn material fibers is prevented. An additional fixed cover can be provided in the interior of the hollow cyinder which causes the closure of the outwardly facing opening. Preferably, a sliver-forming unit is arranged downstream of the pair of rollers. The unit can be formed by a suction drum and a draw-off roller cooperating with the suction drum. In order to join and receive the fiber packages supplied by the pair of rollers it is proposed that the inner chamber of the suction drum is connected with a negative pressure source and covers are provided on the inner side of the suction drum which cut off the inner chamber from the ambient air with the exception of a partial section before the nip point between the suction drum and the draw-off roller. In order to grasp and retain any residual components such as neps, conglutinations, etc. which are not discharged by the air stream, it is proposed that an advanceable combing element is provided between the nip element and the pair of rollers. Said combing element is comparable to a top comb of a combing machine which pierces the fiber material to be detached during the detaching process. The same function would also be fulfilled by the combing element in the presently claimed embodiment. The sliver-forming unit can also be formed by a revolving conveyor belt which is arranged transversally to the discharge direction of the pair of rollers. It is advantageous in this respect to provide the conveyor belt with air-permeable openings and to provide a means for producing a negative pressure at least below the delivery zone onto the conveyor belt. This ensures a secure discharge of the fiber packages onto the conveyor belt. An apparatus is further proposed with at least one guide means being provided which extends along the free end of the fiber structure and the fiber structure is supplied to the fiber sorting device via a conveying means which cooperates with a guide element. This ensures that the free end is guided on one side during the blowing process. Preferably, a movably held nip element cooperates with the guide element and forms a nip point with the same. It is proposed further that in the guide element at least one air nozzle is provided whose opening opens between the free end of the fiber structure and the guide means downstream of the nip point and is connected with a compressed air source. This allows producing an air flow between the free end of the fiber structure and the guide element, which preferably can be a plate. A negative pressure zone is produced by the air flowing along the plate, which negative pressure zone causes the free end to be pulled towards the surface of the plate and thus ensures the flow through the free end with air. The same effect was already utilized in another type of application, namely for detaching a lap end from a lap roll which has been described in EP-A1 482 475 for example. In this case, however, the air stream is only used for detaching the web and not for selection purposes, since in this case there is no defined nip line and the detaching process occurs in intervals of at least three hours. By proposing to provide the end of the guide means or the plate with a flexible arrangement, it is possible for the blowing process or the transfer process of the blown- out end to bring the free end of the plate to another position which supports or facilitates the aforementioned processes. This adjustment can be performed by the adjusting device proposed below which engages on the free end of the plate. In order to suck off the separated components it is advantageous when suction devices are arranged in the zone of the free end of the guide means which is opposite of the free end of the fiber structure. It is proposed further to provide a pair of displaceable rollers downstream of the nip point or to provide a sliver-forming unit downstream of the pair of rollers. This allows moving the pair of rollers towards the free end after the blowing process in order to draw off a fiber package from said end. Further advantages are explained and described in closer detail by reference to the enclosed drawings, wherein: Fig. 1 shows a schematic side view of a first embodiment of a fiber sorting device as claimed in accordance with the invention; Fig. la to Ic shows a schematic representation of the process of forming the fiber package. Fig. 2 schematically shows a fiirther embodiment of the fiber sorting device as claimed in accordance with the invention; Fig. 3 shows an enlarged partial sectional view of fig. 2. Fig. 4 shows several embodiments of nozzle openings; Fig. 5 shows a variant of an embodiment of a sliver-forming unit according to fig. 2; Fig. 6 shows a schematic top view of fig. 5; Fig.7 shows a schematic representation of a further embodiment of a fiber sorting device as claimed in accordance with the invention. Fig. 1 shows a drafting arrangement 1 in which a sliver 10 is drafted for example. As an apron drafting arrangement the drafting arrangement 1 is equipped with a pair of aprons 2. The drafted sliver 10 which is supplied by the apron 2 is supplied between a subsequent suction drum 3 and a roller 5 which is opposite of the suction drum 3. A belt 6, which is placed over further rollers 7 and 8, is partly wrapped around the roller 5. Roller 7 is connected with a schematically indicated drive 12. As is shown schematically, the suction drum 3 is rotatably held in guide rolls 14, with at least one of the guide rolls being connected with a drive 15. Elastic nipping strips 18 are attached on the outside jacket of the suction drum 3, which strips extend axially parallel to the axis of rotation of the suction drum. • A fixed conduit 20 is arranged in the interior of the suction drum 3 which is open towards the side of the inner wall of the suction drum. Conduit 20 is connected to a negative pressure source 22 by way of a schematically shown line 21. An air stream is produced as a result in this zone of the suction drum jacket which acts from the outside to the inside. This is schematically indicated by the arrows shown with the broken lines. As is also shown, a respectively prepared fiber package 24 is disposed in the zone of conduit 20 and Is held on the outside jacket SU of the suction drum by the negative pressure applied in conduit 20. The detaching process to obtain fiber package 24 will be described below in closer detail. A separating drum 30 is rotationally movably held below the suction drum 3, which separating drum is provided in its interior with a fixed pipe32. The inner space of the pipe 32 is connected with the negative pressure source 34 by way of a schematically shown line 33. The pipe 32 is provided in the axial direction with a slot 36 which can correspond with air slots 38 which face radially outwardly and are disposed circularly around the tube. The separating drum 30 is arranged in such a way that the slot 36 is sealed off from the ambient environment of the separating drum 30 when no air slot 38 is opposite of the opening 36. The separating drum 30 is held by way of schematically shown guide rolls 40 in its position, with at least one of the guide rolls 40 being in connection with a drive 42. As seen in the direction of rotation of the separating drum, 30, ejastic nipping elements are fastened to the outside jacket AU behind each of the air slots 38. The function of said elastic nipping elements 44 will be explained below in closer detail. A doffer 46 cooperates on the outside circumference AU of the separating drum 30, which doffer is provided on its circumference with a clothing 47 (shown partly) for example. The fiber material 50 discharged by the doffer 46 (e.g. in the form of a " nonwoven) is conveyed to a pair of draw-off rollers 51 and conveyed to a downstream further processing stage (not shown). The mode of operation of said device is described below: The drafting arrangement 1 is supplied with a sliver 20 for example and drafted in the drafting arrangement. The end E which projects from apron 2 reaches the gap between the circumferential surface SU of the suction drum 3 and the belt 6 which is guided on roller 5. By the rotational movement of the suction drum 3, one of the elastic nipping elements 18 reaches the described zone and nips the end E against the outside surface of belt 6 in the zone of roller 5. As a result of the fact that the circumferential speed of the suction drum 3 is higher than the conveying speed of apron 2, the fibers are pulled out of the end E of the sliver 10 which are nipped between the nipping strip 18 and the belt 6. This leads to a thin fiber package 24 with longitudinally aligned single fibers. Figs, la through 1c show a schematic representation of the process for forming the fiber package 24. Fig. la shows the end E which is supplied by apron 2. A nip line KL is produced through the nipping strips 18 and the nip line KL is displaced with respect to end E. As is shown in fig. 1b, a thin place D is produced and, following the further displacement of the nip point, a fiber package 24 which is detached from the end E, as is shown in fig. 1c. The head K of the fiber package 24 forms a fiber-end-oriented fiber package, with the short fibers substantially being located in the zone of head K. The clamping effect between the belt 6 and the nipping element 18 on the detached fiber package 24 is maintained during the passage through the rollers 5 and 8, thus ensuring a purposeful further conveyance of the fiber package 24 without any changes to its structure (longitudinally aligned fibers). Once the fiber package has passed roller 8, it is held by the applied negative pressure in conduit 20 on the surface SU of suction drum 3. The front end K of the fiber package 24 still rests on the nipping strip 1"8. While the shown fiber package 24 is conveyed in the direction towards the separating drum 30, further fiber packages 24 (not shown) are extracted from the end E by the downstream nipping strips 18. The conveyance of the sliver 10 is performed continuously, whereas the draw-off process for producing the fiber packages 24 occurs discontinuously. Following further transport or further rotation, the indicated fiber package 24 reaches the discharge zone A between the suction drum 3 and the downstream separating roller 30. As a result of the simultaneous rotation of the separating roller 30, a nipping element 40 impinges on fiber package 24, thus producing a nip between the outside jacket SU of the suction drum 3 and the nipping strip 44. The angular position during the operation of the suction drum 3 and the separating drum 30 is chosen in such a way that the nip line produced by the nipping strip 44 is performed at a distance from the front end K of the fiber package 24. Said distance to the head end of the fiber package can be regarded as being equal to the setting distance in the combing machine and can be set by changing the angular position between the drums 3 and 30. Shortly after producing the said nip, the end of the suction slot 38 is in overlap with the opening 36, thus producing an air stream to the inside as a result of the negative pressure in tube 32. As a result, the front end or head K of the fiber package 24 which projects over the nip point of the nipping element 44 is pulled into the suction slot 38. Ail components of the end which project into the suction slot 38 and are not nipped by the nipping element 44 (short fibers) are extracted from the fiber package 24 by the air stream and discharged inwardly into the conduit 32. The negative pressure source 34 is used to discharge from the zone of tube 32 the material carried off to conduit 32. The fixed disposal tube 32 can be arranged in such a way that any deposited impurities between the fixed part and the rotating part of the separating drum are continuously also sucked off. In the course of a further rotation of the drum 30, the forward end of the fiber package 24 remains in the slot 38; the rear end is slightly lifted by the occurring centrifugal force. Once said rear end has reached the zone of the adjacent doffer 46, it is grasped by the clothing 47, as a result of which the fiber package 24 is entrained and pulled out of the air slot 38. During said entrainment, the end of the fiber package 24 is placed on the trailing end of a previously drawn fiber package, as a result of which a roof-tile-like connection is produced. The thus formed nonwoven 50 can then be supplied to a downstream pair of draw-off rollers 51 for further conveyance to subsequent processing steps. The representation of special detaching devices for the nonwoven 50 from the doffer 46 was omitted. Reference is hereby made to respective elements which are already used in the run-out section of a carding machine. The embodiment shown herein only represents a possible variant to implement the invention. A further variant will be described below. In fig. 2, a sliver F1 and F2 each is supplied by way of rollers 54 and 55 to the zone of a conveying trough M1 and M2 of a guide part 58. A feed roller 60 and 61 engages in the respective conveying trough M1 and M2. The guide part 58 is provided between the conveying troughs M1, M2 with an air slot 63 which is provided with an opening 64. This is also shown, particularly in the enlarged representation according to fig. 3, Fig. 4 shows various possibilities as to how this opening 64 can be arranged. The opening in fig. 4a) is provided with a longitudinal slot 66 which extends over the width of the guide part 58. In the representation according to fig. 4b), several adjacently disposed holes 67 are used for the air passage. Fig. 4c) shows a further embodiment, with a larger number of holes 68 being provided for the air passage. In the representation according to fig. 4d), adjacently disposed cross-recessed-like openings 69 are used. It is certainly possible to provide more combinations and embodiments which can be used for the respective application. As is shown schematically, the air slot 63 is connected with a compressed air source 71 via a line 70. Above the aperture zone (opening 64 of air slot 63), a nipping element 75, 76 each exert a nipping effect on the downwardly conveyed slivers F1 and F2 and form on the guide part 58 a nip point K1 and K2. The downwardly guided ends of the slivers F1 and F2 are joined below the opening 63 and form a joint free end E1. As is shown in particular in fig. 3, the air stream which starts out from air slot 63 is directed between the two mutually superimposed ends of slivers F1 and F2 which form a joint end E1. The function of this device will be explained below in closer detail. . As is also shown in fig. 3, additional air nozzles 77 and 78 which are distributed over the width can be provided in the zone of the ends of the nipping elements 75 and 76, which air nozzles are in connection with an excess pressure source 81 via schematically shown lines 79, 80. Said nozzles 77 and 78 are used to produce an additional compressed air stream in the direction towards the trailing end E1, which air stream can penetrate the end El substantially from the outside to the inside. Said additional compressed air streams ensure that the entire end E1 is completely flowed through with air, so that all components (short fibers, dirt, neps, etc.) which cannot be held back by the nip points K1 and K2 are discharged downwardly by the air stream. Roller 83 is provided with a revolving hollow body 87 which is provided with an opening 89. In the interior of the revolving body 87, a fixed cover 88 is provided which is provided with an opening 90. As is shown schematically, the interior space of cover 88 is provided with a negative pressure source 92 by way of the line 93. This shows that once the openings 89 90 are in overlap, material separated from the end E1 can be sucked off via the interior space of the cover 88, The roller 82 is arranged as a full roller and can be provided with a rubber coating for the draw-off process. A sliver forming unit 95 is disposed below the pair of rollers 85, which sliver forming unit is composed of a revolving suction drum 97 and a rubber-proofed roller 99 which cooperates with the suction drum. A fixed cover 98 is arranged in the interior of the suction drum 97 whose interior space is connected with a negative pressure source 102. In the zone of the nip point 101 between the roller 99 and the suction drum 97 the cover is provided with openings 100. The openings, which allow the suction of ambient air, are shown in the indicated example with a different cross-sectional surface. The cross-sectional surface of the opening 100 is smallest closest to the nip point 101. This means that the suction force on the removed fiber package FP is the smallest in this zone, whereas it becomes larger with gradually increasing cross-section of the openings 100. This is to ensure that the ends of the drawn-off fiber packages FP rest securely on the outside circumference of the suction drum 97. This device allows layering in a roof-tile-like manner the fiber packages FP which are supplied downwardly step-by-step in such a way that finally a sliver B is formed which can be drawn off downwardly by way of a downstream pair of rollers 104 in order to transfer the same to subsequent collecting devices for example (cans). As is shown additionally in fig. 3, an advanceable combing element 105 can be provided between the nipping elements 75, 76 and the pair of rollers 85, which combing element is provided with two advanceable combing elements 106, 107. This combing element 105 can be compared with the top comb of a combing machine and then comes into engagement with the free end E1 when a fiber package is drawn off downwardly from said end E1 by way of the pair of rollers 85. This allows to withhold and remove during the draw-off process any short components and also any impurities which have not been completely separated by the air stream. This means that the combing element 105 acts as an additional separating aid. Fig. 5 shows a further possibility of a sliver forming unit 95 where instead of a suction drum, a revolving conveyor belt 110 is used which is provided with air-permeable openings 111. This is also shown in particular in fig. 6. The conveyor belt 110 is guided via two rollers 112, 113, with one of said rollers being in connection with a drive (not shown in closer detail). An upwardly open conduit 115 is provided on the interior side of the revolving conveyor belt 110 which is connected via a line 116 with a negative pressure source 117. Said conduit 115 is attached in the zone of the conveyor belt in which the fiber packages drawn off by the pair of rollers 85 are layered in roof-tile-like manner in order to form a closed sliver B. In the representation according to fig. 6 it is shown by the schematically indicated axes A1 and A2 that the axes of the pairs of rollers 85 can also be aligned inclined to the draw-off direction T. This can provide an additional effect with respect to the blurring of the piecing positions. The mode of operation of the embodiment of figs. 2 through 6 is now explained below in closer detail. The slivers F1 and F2 which are supplied via rollers 54 and 55 (instead of the slivers it would also be possible to supply nonwovens or webs) reach the zone of the feeding troughs M1 and M2, as a result of which they are grasped by the rollers 60 and 61 and are further conveyed. Below the opening 63 of the guide part 58 the ends of slivers F1, F2 are joined into a single end E1. Once the free end E1 has reached a predefined excess projecting length below the guide part 58, the supply via rollers 54, 55 and the rollers 60 and 61 is interrupted. A mechanism (not shown) is used to displace (swivel) the nipping elements 75 an 76 in the direction towards the guide part 58, which elements form a nip point K1, K2 on the sliver F1 and F2. Thereafter an air impulse is produced via the compressed air source 71 through the opening 64 of the air gap 63 which penetrates the free end El and extracts any unnipped components (e.g. short fibers) from the end E1. As is shown in particular in fig. 3, the air stream, starting out from air slot 63, penetrates the end El in the zone where the two ends of slivers F1 and F2 overlap. As a result of the so-called "Bernoulli effect", the two components of the free end E1 are held together, thus ensuring that the complete fiber material of end El is penetrated by air. In order to further increase the separating effect, additional air impulses can be applied by the nozzles 77 and 78 on the end E1. After ending the blowing interval, the nip points K1 and K2 are released again by retracting the nipping elements 75 and 76. During the blowing process the roller 83 assumes the indicated position, with the opening 89 being disposed opposite of the opening 90 and the separated material being discharged through the openings \with the help of the negative pressure source 92. It would also be possible to provide additional suction devices which are not shown here. As arranged by a double arrow, the guide part 58, including the rollers 54, 55 and 60, 61, can be displaced in the direction towards the pair of rollers 85, so that the tip of the blown-out end El reaches the nip point"between the rollers 82 and 83. It is also possible, instead of the movement of the guide part 58 towards the pair of rollers 85, to displace the pair of rollers 85 in the direction towards the guide part 58 in order to grasp the fibers of the free end El. Once the end E1 is held in the nip point of the pair of rollers 85, the comb as shown in fig. 3 can be advanced. The opening 89 of the hollow body 87 is now in a position which is opposite of the position as shown in fig. 2. This means that the closed jacket of the hollow body Is used tor the draw-off process. The pair of rollers 85 is now put into motion and a fiber package FP is drawn off from the end El which is grasped by the nip point of the pair of rollers 85. Said fiber package FP is transferred downwardly to a nip point 101 of the pair of rollers 95 where the released rear end of the fiber package FP comes to rest on the suction drum 97, which is supported by the openings 100 which are in connection with the negative pressure chamber of cover 98. The front end of the fiber package FP is joined with an end still located in the nip point 101 of a previously drawn-off fiber package FP, or it is layered with the same in a roof-tile-like manner. The thus formed sliver B is discharged downwardly by way of the nip point 101 to a pair of rollers 104 for further conveyance. The embodiment according to fig. 5 and fig. 6 is applied instead of the pair of rollers 95 and is provided with a revolving and air-permeable conveyor belt 110. The fiber package FP which is supplied downwardly to the pair of rollers 85 is layered on the ends of the previously supplied fiber packages and connected to the same in a roof-tile¬like manner. This process is supported by the application of a negative pressure via conduit 105, as a result of which the free ends and also the formed sliver or nonwoven B are held in a positioned manner on the surface of the conveyor belt 110. It is also possible to arrange several fiber selection devices above the conveyor belt 106 which all supply the selected fiber material onto the same conveyor belt and join the same into one joint structure. Fig. 7 shows a further embodiment which is provided with an arrangement similar to the example of fig. 2. Instead of a second supplied fiber structure there is a guide plate 127 which stands opposite to the end E2 of the fiber structure F3. One or several slivers F3 (or lap, nonwoven, etc.) are conveyed in the direction towards a nip point K3 via the guide part 121 which is provided with a guide trough MS under the influence of a feed roller 120. The nip point K3 is situated at the tapering end of the guide part 121 and is produced by an adjustably arranged nipping element 132. The adjusting movement of the nipping element 132 is shown schematically with a double arrow. An air slot 123 is attached in the interior of the guide part whose opening ends below and in front of the nip point K3. The opening can be arranged according to the embodiments shown in fig. 4. The air slot is connected via line 124 with a negative pressure source 125. It is also possible, as is shown in fig. 3, to provide an additional advanceable combing element 105 in this case too. A displaceably held plate 127 is attached below the guide part 121 whose front end 122 is provided with a flexible arrangement. A lever 126 acts on said end, which lever is in connection with an adjusting mechanism not shown in closer detail. This lever 126 can be used to move the end 122 to the positions as shown in the dot-dash lines. For the purpose of horizontal guidance of the plate 127 a guide element 128 is provided and in the rear zone of the plate a cylinder 130 acts on the point of articulation 129 which is used for displacing the plate. A suction device 134 is provided above the plate 127 which is used for removing the separated waste material. A horizontally displaceable pair of rollers 135 is attached adjacent thereto which is provided for drawing off fiber packages from the selected end E2. As has already been described in the embodiment of fig. 2, a sliver forming unit 137 is - provided downstream ^3f the pair of rollers 135, which sliver forming unit comprises a rotatably held suction drum 138 and a cover 139 arranged in the interior of the suction drum, which cover is provided with openings 140 in the draw-off zone in front of the nip point 144. The interior space of the cover 139 is connected with a negative pressure source 147. A roller 141 cooperates with the suction drum 138 which can be provided with a rubber coating. The sliver supplied by the suction drum is conveyed further by a pair of rollers 145. The function of this device is now briefly described below: The fiber material F3 is conveyed via the feeding trough MS and the feeding cylinder 120 via the zone of the nip point K3. The plate 127 assumes the straight and most forward position shown in the enhanced print. Once the excess projecting end of the free end assumes a defined value beyond the nip point K3, the nipping element 132 is displaced in the direction towards the guide part 121 and the fiber material F3 is nipped at the nip point K3. The conveyance was interrupted in the meantime. The front end of the plate 127 is displaced by way of lever 126 to the above position as shown in the dot-dash line, as a result of which the free end E3 is also entrained with the plate 127. A compressed air stream is produced by way of the compressed air source 125 and the air slot 123 which progresses in the direction of a suction device 134 which has been activated in the meantime. As a result of the air stream which is guided along the surface of plate 127, the end E2 (as described above) is pulled onto the plate and is blown through completely by the air stream. The short fibers extracted from the end E2 and the other extracted components are carried off via the suction conduit 134. The supply of compressed air is interrupted again and the nipping element 132 is lifted from the guide part 121 again. At the same time, the end 122 is swiveled by way of lever 126 to the downward position (dot-dash • line) and displaced reanwardly via the cylinder 130. This produces sufficient free space, so that subsequently the pair of rollers 135 can be displaced in the direction towards the nip point K3 until the free end E2 is grasped in the nip point of the pair of rollers 135 and is drawn off. This draw-off process is comparable with the detaching process in a conventional combing machine. Once a fiber package has been pulled out of the free end E2 in this way, the pair of rollers is displaced in the direction towards a downstream sliver forming unit 137. Said fiber package is placed there in a roof-tile-like manner on the end of a previously supplied fiber package (piecing process) and joined to the same in the nip point 144. Tlhereafter the thus formed sliver.B reaches a pair of rollers 145 which supplies the material to a downstream receiving apparatus (can) (not shown). In the meantime the end of plate 127 was conveyed back to the stretched and forward position and the selection and subsequent draw-off process begins anew. The embodiments shown herein are only exemplary. Further embodiments are possible within the scope of the invention. The shown devices allow performing a purposeful selection of fibers without requiring the use of large accelerations of mass and reversing movements and with high working speeds. WE CLAIM: 1. A method for sorting the fibers of a fiber structure (10, Fl, F2) which is supplied to a fiber sorting device (30, 38, 75, 76, 58, 63), characterized in that it comprises the steps of nipping the fiber structure (10, Fl, F2) transversally to its conveying direction in a definite distance from the effective end of the fiber strand; exposing the free end projecting beyond the clamping point with an air flow; extracting and removing from the free end, any non-nipped components such as short fibers, neps, dust etc. 2. The method as claimed in claim 1, wherein the fiber structure (10) is divided prior to reaching the sorting device (30) into individual fiber packages (24) with single fibers which are stretched in the longitudinal direction and are aligned approximately parallel to one another. 3. The method as claimed in claim 2, wherein the fiber packages (24) following successively at a distance from one another are formed by intermittent extraction of fibers from the free end (E) of the fiber structure. 4. The method as claimed in any one of the claims 2 to 3, wherein, as seen in the conveying direction of the fiber package (24), the fiber package is nipped during the sorting process at a predetermined distance from its forward end (K) which is subjected to the air stream. 5. The method as claimed in any one of the claims 1 to 3, wherein the air stream, as seen from the nip point (Kl, K2), is directed towards the free end (El) of the fiber structure (Fl, F2) or fiber package (24). 6. The method as claimed in any one of the claims 1 to 5, wherein the free end (El) which projects beyond the nip point (Kl, K2) is subjected to a suction air stream. 7. The method as claimed in any one of the claims 1 to 5, wherein the free end (El) which projects beyond the nip point (Kl, K2) is subjected to a compressed air stream. 8. The method as claimed in any one of the preceding claims, wherein after the sorting process the nip force is released at the nip point (Kl, K2) and the sorted fiber material is transferred to a downstream sliver forming unit (95) for the formation of slivers. 9. The method as claimed in any one of the claims 2 to 7, wherein the sliver formation is performed by a partial super positioning of the sorted fiber packages (24). 10. The method as claimed in claim 1, wherein at least two fiber structures (Fl, F2) are supplied to the fiber sorting device simultaneously and the ends of the fiber structures are subjected to a common air stream. 11. The method as claimed in claim 10, wherein the ends of the fiber structures (Fl, F2) are joined and air is blown between the ends of the fiber structures, starting out from the zone of the nip points (Kl, K2). 12. The method as claimed in claim 10, wherein at least one additional compressed air stream is produced downstream of the respective nip point (Kl, K2) in the direction towards the free end and onto the outside surfaces of the joined ends (El) of the fiber structures (Fl, F2). 13. An apparatus for the sorting of fibers of a fiber structure (10, Fl, F2) which is supplied by means of feeding means (1, 3, 54, 55, 60, 61, 58) to a fiber sorting device, characterized in that nipping apparatuses (44, 75, 76) are provided which nip the fiber structure (24, Fl, F2) at a distance from its free end (El) and means (33, 34, 36, 38, 63, 70, 71) are present which produce an air stream from the nip point (Kl, K2) to the free end (El) of the fiber structure. 14. The apparatus as claimed in claim 13, wherein means (18, 5, 6) are provided in order to open the fiber structure (10), which is supplied by the feeding means (1), in a step-by-step manner into individual fiber packages (24) with single fibers which are stretched in the longitudinal direction and are aligned parallel with respect to one another, and with means (3) to transfer the fiber packages to a downstream sorting device (30, 38, 75, 76, 58, 63). 15. The apparatus as claimed in claim 14, wherein the feeding means are formed by a drafting arrangement (1) and the means for producing individual fiber packages (24) consists of a rotatably held roller (5) which together with a rotatably held suction drum (3) form a nip point which is opposite of the delivery point of a drafting arrangement (1). 16. The apparatus as claimed in claim 15, wherein the roller (5) is enclosed by a circularly held belt (6) over a partial zone of its circumference, at least in the zone of the nip point. 17. The apparatus as claimed in claim 16, wherein adjacent to the nip point the belt (6) rests on the circumference of the suction drum (3) over a partial section thereof 18. The apparatus as claimed in any one of the claims 15 to 17, wherein the suction drum (3) is provided with elevations (18) which are distributed in a spaced manner on its circumference. 19. The apparatus as claimed in any one of the claims 15 to 18, wherein the drafting arrangement (1) is an apron drafting arrangement. 20. The apparatus as claimed in any one of the claims 15 to 19, wherein a rotatably held separating drum (30) is assigned axially parallel to the suction drum (3) which separating drum is provided with several radially outwardly facing suction slots (38), with the position of the suction slots corresponding to the smallest distance fi-om the outside circumference (SU) of the suction drum (3) with a negative pressure chamber (32) which is fixedly arranged in the interior of the separating drum (30) and is connected with a suction means (34). 21. The apparatus as claimed in claim 20, wherein, as seen in the direction of rotation of the separating drum (30), elastic elevations (44) are provided adjacent to the respective opening of the suction slots (38) on the outside circumference (AU) of the separating drum (30), which elastic elevations exercise a nipping effect on the outside circumference (SU) of the suction drum in the position of the smallest distance between the suction drum (3) and the separating drum (30). 22. The apparatus as claimed in any one of the claims 20 to 21, wherein means (20, 21, 22) are provided at least in a partial zone between the zone where the belt (6) rests on the outside circumference (SU) of the suction drum (3) and the transfer zone (A) to the separating drum (30) in order to produce a negative pressure in the interior of the suction drum (3). 23. The apparatus as claimed in any one of the claims 20 to 22, wherein a rotatably held doffer (46) is provided axially parallel to the separating drum (30), which doffer touches the outside circumference (AU) of the separating drum (30). 24. The apparatus as claimed in claim 23, wherein the doffer (46) is provided with a clothing (47) on its outside circumference. 25. The apparatus as claimed in claim 13, wherein the fiber sorting device is supplied with at least two fiber structures (Fl, F2) via conveying means (54, 55, 60, 61) and movably held nipping elements (75, 76) are provided for each fiber structure, which elements co-operate with a common guide element (58). 26. The apparatus as claimed in claim 25, wherein at least one air nozzle (63) is provided in the guide means (58) whose opening (64), as seen in the conveying direction of the fiber structures (Fl, F2), opens downstream of and between the nip points (Kl, K2) and is connected with a compressed air source (71). 27. The apparatus as claimed in any one of the claims 25 to 26, wherein the guide element (58) is provided with mutually opposite guide troughs (Ml, M2) into which a conveying roller (60, 61) used as a conveying means is immersed. 28. The apparatus as claimed in any one of the claims 25 to 27, wherein air nozzles (77, 78) are integrated in the nipping elements in the zone and downstream of the nip surfaces of the nipping elements (75, 76) and are in connection with a compressed air source (81). 29. The apparatus as claimed in any one of the claims 24 to 28, wherein a pair of rollers (85) which forms a nip line is arranged downstream of the nipping elements (75,76). 30. The apparatus as claimed in claim 29, wherein at least one of the rollers (82, 83) of the pair of rollers (85) is provided as a hollow cylinder (87) with outwardly facing openings (89), with the hollow chamber being connected with a negative pressure means (92). 31. The apparatus as claimed in any one of the claims 29 to 30, wherein a sliver forming unit (95) is arranged downstream of the pair of rollers (85). 32. The apparatus as claimed in claim 31, wherein the sliver forming unit (95) is formed by a suction drum (97) and a draw-off roller (99) which co-operates with the suction drum. 33. The apparatus as claimed in claim 32, wherein the interior space of the suction drum (97) is connected with a negative pressure source (102) and covers (98) are provided on the inner side of the suction drum (97) which seal off the interior space against ambient air up to a partial section in front of the nip point (101) between the suction drum (97) and the draw-off roller (99). 34. The apparatus as claimed in any one of the claims 25 to 33, wherein an advanceable combing element (105) is provided between the nipping elements (75, 76) and the pair of rollers. 35. The apparatus as claimed in any one of the claims 29 to 34, wherein the guide means (58) is held displaceably in the direction towards the pair of rollers (85). 36. The apparatus as claimed in claim 31, wherein the sliver forming unit (95) is made of a revolving conveyor belt (110) which is arranged transversally to the discharging direction of the pair of rollers (85). 37. The apparatus as claimed in claim 36, wherein the conveyor belt (110) is provided with air-permeable openings (111) and means (115, 116, 117) for producing a negative pressure are provided at least below the delivery zone on the conveyor belt. 38. The apparatus as claimed in claim 13, wherein at least one guide means (127) is provided which extends along the free end (E2) of the fiber structure (F3) and the fiber structure (F3) is supplied to the fiber sorting device by means of a conveying means (120) which co-operates with a guide element (121). 39. The apparatus as claimed in claim 38, wherein at least one movably held nipping element (132) is provided which co-operates with the guide element (121). 40. The apparatus as claimed in any one of the claims 38 to 39, wherein at least one air nozzle (123) is provided in the guide element (121) whose opening opens downstream of the nip point (K3) between the free end (E2) of the fiber structure (F3) and the guide means (127) and is connected with a compressed air source (125). 41. The apparatus as claimed in any one of the claims 38 to 40, wherein the guide means (127) is formed by a plate which is displaceable in the longitudinal direction. 42. The apparatus as claimed in any one of the claims 38 to 41, wherein the end (122) of the guide means (127) facing the free end (E2) of the fiber material (F3) is flexible. 43. The apparatus as claimed in claim 42, wherein the flexible free end (122) of the guide means (127) is connected with an adjusting device (126). 44. The apparatus as claimed in any one of the claims 38 to 43, wherein suction devices (134) are arranged in the zone of the free end (122) of the guide means (127) which is opposite of the free end (E2) of the fiber structure (F3). 45. The apparatus as claimed in any one of the claims 38 to 44, wherein the nip point is provided downstream with a displaceable pair of rollers (135). 46. The apparatus as claimed in claim 45, wherein a sliver forming unit (137) is provided downstream of the pair of rollers (135).

Full Text

The invention relates to a method and an apparatus to perform the method for sorting the fibers of a fiber structure which is supplied by feeding means to a fiber sorting device.
in order remove short fibers, neps, dirt and other components from a fiber mixture it is known to supply the fiber material in the form of lap rolls to the combing machines for combing. In this process, the end of the web is nipped by a nipper and the end projecting beyond the nip point of the nipper is mechanically combed out by a combing unit of a circular comb. Damage to the fibers may occur under certain circumstances during this combing process. The disadvantage in the known methods is also the discontinuous mode of operation, whereby it is necessary to reverse large masses during the working cycle.
An apparatus was therefore proposed in the published PCT application WO 98/04765 to _ perform the separation of short fibers, dirt and other components by means of an air flow, with the air flow being substantially produced in the conveying direction of a nonwoven. During this process the nonwoven guided through an air conduit is subjected at two places to a holding force, so that it is ensured that the long fibers to be gained are not carried off by the air flow.
A certain separating effect could already be achieved with this device. It was not yet satisfactory, however, because it was difficult to purposefully extract all short fibers from the endless nonwoven with"the air stream.
In a further, still unpublished Swiss patent application of the applicant with the application number CH-254/98 of 3 February 1998, it was proposed in this system for the purpose of increasing the separating effect to prepare the fiber material first in a respective manner before it reaches the separating conduit. It was proposed therein to prepare the fiber material into individual and adjacent, longitudinally arranged single fibers before it is subjected to the air flow. It was noticed that an improved separating

effect was produced and that fewer long fibers (batch-fibers) were contained in the waste. In order to further increase the separating effect it was proposed to guide the thus prepared nonwoven over several successively switched separating stages. Although it was managed to improve the separating effect and the separating quality with this device, they were still not yet adequate. The goal of achieving the degree and quality of separation of a conventional combing machine could not yet be achieved with this device.
Based on the mentioned devices and state of the art the invention is now based on the object of providing a method and an apparatus by which a higher degree of separation and a higher quality of separation can be achieved as compared to the known pneumatic methods.
This object is achieved, on the one hand, by a method in which the fiber structure is nipped transversally to its direction of conveyance and the free end projecting from the nipped position is subjected to an air flow which is capable of extracting and carrying off any undamped components (such as short fibers, neps, dust, etc.) from the free end.
In this proposed method the selection process (sorting process) is performed with air as in a mechanical separating process in the combing machine on an open end of the fiber ■ structure (lap, nonwoven, fiber structure, etc.). The air flow produced in the direction towards the free end of the fiber structure allows blowing out and carrying off undamped components. The intensity of the air flow depends on the size of the supplied fiber mass.
In order to improve the separating effect it is proposed that the fiber structure, prior to reaching the sorting device, is broken down into individual fiber packages with single fibers which are substantially stretched in the longitudinal direction and are in approximately parallel alignment to one another. This allows exercising a purposeful nipping effect on the now present, longitudinally stretched fibers, which ensures that only very few long fibers are entrained during the sorting process.

in order to produce the fiber packages it is proposed that fiber packages are discontinuously produced from the free end of the fiber structure by way of a respective draw-off element. Such a preparation of the fibers into thin fiber packages or tufts is already known from the principle of the fibroliner. According to this principle the fiber packages are arranged at ends, with the short fibers being disposed in the forward end (nip line) of the fiber packages. With a fiber mass which is prepared in such a way it is possible to perform a purposeful nipping effect in the subsequent selection process (sorting process) in order to remove the short fibers disposed in the head end.
It is proposed further that, as seen in the conveying direction of the fiber package, the fiber package is nipped during the sorting process at a predetermined distance to its front end which is subject to the air flow. Said front distance to the head end of the fiber package can be compared with the setting distance of the card. All short fibers which are disposed in the head zone and are not held by the nip are removed upon application of the air flow.
It is preferably proposed that the air flow, as seen from the nip point, is directed in the direction towards the free end of the fiber structure or fiber package.
The air flow can be produced by a source of pressure below or above atmospheric.
It is proposed further that after the sorting process the nip force at the nip point is released and the sorted fiber material is transferred to a downstream sliver-forming unit for forming the sliver.
The formation of the sliver can be produced by superimposing layers of the sorted fiber packages. This method corresponds to the piecing process in conventional combing machines.
A method is further proposed, with at least two fiber structures being supplied to the fiber sorting device simultaneously and the ends of the fiber structures being subjected to a common air flow. It is advantageous in this respect when the ends of the individual

fiber structures are joined together and the air is blown between the ends of the fiber structures, starting from the zone of their nip points. This allows blowing compressed air in a purposeful manner into the joined ends in order to grasp and separate all short fibers which are disposed in the interior of the ends and are not nipped in any way.
In order to intensify the separating effect it is proposed that at least one additional compressed air flow is produced downstream of the respective nip point in the direction towards the free end and onto the outside surfaces of the joined ends of the fiber structures. It is possible to apply the air pulses thus produced in different time intervals.
The invention is also achieved by an apparatus, with nip apparatuses being provided which nip the fiber structure at a distance from its free end and means are present which produce an air flow from the nip point to the free end of the fiber structure.
In order to prepare the fiber structure it is proposed that means are provided in order to open the fiber structure into individual fiber packages with single fibers which are substantially stretched in the longitudinal direction and are aligned parallel to one another, which fiber structure is supplied step-by-step by the feeding means, and with means for transferring the fiber packages to a downstream sorting device. It is important in this respect that the structure of the formed fiber packages or the longitudinal alignment of the fibers is maintained during the transfer to the actual sorting device.
It is proposed that the feeding means are formed by a drafting arrangement and the means for producing the individual fiber packages consist of a rotatably held roller which forms a nip point together with a rotatably held suction drum which is opposite of the delivery place of the drafting arrangement. Preferably, the drafting arrangement can be an apron drafting system.
In order to perform a purposeful draw-off process of the fiber package and to precisely guide the fiber package after the draw-off process it is proposed that the draw-off roller is enclosed with a revolvingly held apron over a partial section of its circumference, at least in the zone of the nip point.

It is advantageous in this respect if the apron rests after the nip point on the circumference of the suction drum over a partial section of the same. This ensures the ideal guidance of the formed fiber package. This means that the fiber package is guided in a forced way, thus ensuring that the individual fibers retain their position when transported off.
In order to intensify the nipping effect during the draw-off process of the fiber package from the end of the fiber structure it is proposed that the suction drum is provided with elevations which are distributed in a spaced manner on the circumference of the same. These elevations form in combination with the apron which is placed around the draw-off roller a secure nip point and ensure a secure entrainment of the fibers held in the nip point. The elevations can be made of elastic material in order to produce a careful nip. It is also possible to provide the draw-off roller co-operating with the suction drum with an elastic cover.
A further embodiment is possible in that the elevations on the suction drum are omitted and are applied on the revolving apron instead. It only needs to be ensured that in the take-off zone between the suction drum and the draw-off roller it is possible to apply a purposeful nip force in order to pull out the fiber packages from the end of the supplied fiber structure. Moreover, the secure further transport without causing any compressions must be ensured.
The distance between the elevations fastened between the suction drum and the apron must be larger than the length of the longest fiber in the fiber structure.
In order to support the guidance of the drawn fiber packages it would be possible to apply a negative pressure in the interior of the suction drum in the draw-off zone, so that the ends will securely come to rest on the suction drum.
It is further proposed that a rotatably held separating drum is assigned in an axially parallel manner to the suction drum, which separating drum is provided with several radially outwardly facing suction slots, with the suction slots corresponding with a

negative pressure chamber in the position of the smallest distance to the outside circumference of the suction drum, which negative pressure chamber is fixedly arranged in the separating drum and is provided with a suction means. The distance between the outside jacket of the suction drum and the separating drum can be chosen in such a way that at the time of applying a negative pressure a nipping effect is exercised on the fiber package in the respectively positioned suction slot. The nip line thus produced is located at a distance from the front end of the fiber package, as a result of which all non-nipped components (such as short fibers) are carried off into the suction slot by the produced air stream.
In order to achieve a precise and defined nip point it is proposed that, as seen in the direction of rotation of the separating drum, elastic elevations on the outside circumference of the separating drum adjacent to the respective opening of the suction slots, which elevations exercise a nipping effect with the outside circumference of the suction drum at the position of the smallest distance between the suction drum and the separating drum. In this embodiment there is a distance between the outside jacket of the suction drum and the separating drum, with the distance being smaller than the height of the elastic elevation in the radial direction of the separating drum. This ensures that the elastic elevation deforms in this zone and can thus exert a pressure force on the fiber package.
For the purpose of a secure transfer of the fiber packages it is proposed that means are provided to produce a negative pressure in the interior of the suction drum at least in a partial zone between the region where the apron rests on the outside circumference of the suction drum and the transfer zone next to the separating drum. The negative pressure only needs to be large enough, so that the position and the alignment of the single fibers in the fiber package do not change during the transport to the transfer position. It can be partly possible however to remove short components such as dust from the fiber mixture in this zone by the application of the negative pressure.

In order to remove the selected fiber material it is proposed that a rotatably held doffer is provided axially parallel to the separating drum, which doffer touches the outside circumference of the separating drum.
The doffer can be provided with a clothing on its outside circumference.
In order to securely introduce the forward ends of the fiber packages into the respective suction slot for the selection process it is possible to provide an excess pressure source in the interior of the suction drum in order to produce a compressed air flow in the direction towards the suction slot.
A further embodiment of the invention is obtained when the fiber sorting device is supplied with at least two fiber structures by means of conveying means and movably held nipping elements are provided for each fiber structure, which elements cooperate with a common guide element.
It is possible to supply also more than two fiber structures to the fiber sorting device when providing a respective arrangement of the nipping device.
It would also be possible to guide the fiber structures before the nip point by a drafting device in order to prepare the same for the subsequent sorting process.
It is proposed as a further embodiment that at least one air nozzle is arranged whose opening, as seen in the conveying direction of the fiber structures, opens downstream of and*between the nip points and is connected with a compressed air source. The air nozzle extends over the entire width of the supplied fiber structures.
A variant is also possible where several adjacent fiber structures (e.g. slivers) are supplied to the nip point.
The term "fiber structure" can comprise for example a nonwoven, a lap, a sliver or the like. The preferable further developments as explained below can also relate to an

embodiment where only a single fiber structure is supplied to the nip elements (this means without joining the ends of at least two fiber structures).
Concerning the supply of several fiber structures it is proposed further that the guide element is provided with opposite guide troughs into which the conveying roller, which is used as the conveying means, immerses.
In order to intensify the separating effect it is proposed further that air nozzles are integrated in the zone and downstream of the nip surfaces of the nip elements in the nip elements and are in connection with a compressed air source. This also allows pressurizing the end from the side with compressed air in the longitudinal direction, with said end projecting beyond the nip point. The separating effect is thus intensified.
In order to draw off a fiber package from the selected end of the fiber structure it is proposed that a pair of rollers is arranged downstream of the nip elements which form a nip line.
it is possible to provide the feeding devices displaceably in the direction towards the pair of rollers when the nip elements are released, so that the forward end of the fiber structure can be grasped by the nip line of the downstream pair of rollers.
This draw-off process can be regarded as being equivalent to the detaching process of the combed fiber tuft in the combing machine.
In order to discharge the waste material which is released during the blowing process of the free end of the fiber structure it is proposed that at least one of the rollers of the pair of rollers is provided as a hollow cylinder with outwardly facing openings, with the hollow chamber being connected with a negative pressure means. The outwardly facing openings are only present on a partial range of the circumference of the hollow cylinder, so that during the detaching process the closed nip line is present in the pair of rollers on the one hand and a suction of the drawn material fibers is prevented. An additional

fixed cover can be provided in the interior of the hollow cyinder which causes the closure of the outwardly facing opening.
Preferably, a sliver-forming unit is arranged downstream of the pair of rollers. The unit can be formed by a suction drum and a draw-off roller cooperating with the suction drum.
In order to join and receive the fiber packages supplied by the pair of rollers it is proposed that the inner chamber of the suction drum is connected with a negative pressure source and covers are provided on the inner side of the suction drum which cut off the inner chamber from the ambient air with the exception of a partial section before the nip point between the suction drum and the draw-off roller.

In order to grasp and retain any residual components such as neps, conglutinations, etc. which are not discharged by the air stream, it is proposed that an advanceable combing element is provided between the nip element and the pair of rollers. Said combing element is comparable to a top comb of a combing machine which pierces the fiber material to be detached during the detaching process. The same function would also be fulfilled by the combing element in the presently claimed embodiment.
The sliver-forming unit can also be formed by a revolving conveyor belt which is arranged transversally to the discharge direction of the pair of rollers. It is advantageous in this respect to provide the conveyor belt with air-permeable openings and to provide a means for producing a negative pressure at least below the delivery zone onto the conveyor belt. This ensures a secure discharge of the fiber packages onto the conveyor belt.
An apparatus is further proposed with at least one guide means being provided which extends along the free end of the fiber structure and the fiber structure is supplied to the fiber sorting device via a conveying means which cooperates with a guide element. This ensures that the free end is guided on one side during the blowing process. Preferably, a movably held nip element cooperates with the guide element and forms a nip point with the same.
It is proposed further that in the guide element at least one air nozzle is provided whose opening opens between the free end of the fiber structure and the guide means downstream of the nip point and is connected with a compressed air source.
This allows producing an air flow between the free end of the fiber structure and the guide element, which preferably can be a plate. A negative pressure zone is produced by the air flowing along the plate, which negative pressure zone causes the free end to be pulled towards the surface of the plate and thus ensures the flow through the free end with air. The same effect was already utilized in another type of application, namely for detaching a lap end from a lap roll which has been described in EP-A1 482 475 for

example. In this case, however, the air stream is only used for detaching the web and not for selection purposes, since in this case there is no defined nip line and the detaching process occurs in intervals of at least three hours.
By proposing to provide the end of the guide means or the plate with a flexible arrangement, it is possible for the blowing process or the transfer process of the blown- out end to bring the free end of the plate to another position which supports or facilitates the aforementioned processes. This adjustment can be performed by the adjusting device proposed below which engages on the free end of the plate.
In order to suck off the separated components it is advantageous when suction devices are arranged in the zone of the free end of the guide means which is opposite of the free end of the fiber structure.
It is proposed further to provide a pair of displaceable rollers downstream of the nip point or to provide a sliver-forming unit downstream of the pair of rollers. This allows moving the pair of rollers towards the free end after the blowing process in order to draw off a fiber package from said end.
Further advantages are explained and described in closer detail by reference to the
enclosed drawings, wherein:
Fig. 1 shows a schematic side view of a first embodiment of a fiber sorting device as
claimed in accordance with the invention;
Fig. la to Ic shows a schematic representation of the process of forming the fiber
package.
Fig. 2 schematically shows a fiirther embodiment of the fiber sorting device as
claimed in accordance with the invention;

Fig. 3 shows an enlarged partial sectional view of fig. 2.
Fig. 4 shows several embodiments of nozzle openings;
Fig. 5 shows a variant of an embodiment of a sliver-forming unit according to fig. 2;
Fig. 6 shows a schematic top view of fig. 5;
Fig.7 shows a schematic representation of a further embodiment of a fiber sorting device as claimed in accordance with the invention.
Fig. 1 shows a drafting arrangement 1 in which a sliver 10 is drafted for example. As an apron drafting arrangement the drafting arrangement 1 is equipped with a pair of aprons 2. The drafted sliver 10 which is supplied by the apron 2 is supplied between a subsequent suction drum 3 and a roller 5 which is opposite of the suction drum 3. A belt 6, which is placed over further rollers 7 and 8, is partly wrapped around the roller 5. Roller 7 is connected with a schematically indicated drive 12.
As is shown schematically, the suction drum 3 is rotatably held in guide rolls 14, with at least one of the guide rolls being connected with a drive 15.
Elastic nipping strips 18 are attached on the outside jacket of the suction drum 3, which strips extend axially parallel to the axis of rotation of the suction drum.
• A fixed conduit 20 is arranged in the interior of the suction drum 3 which is open towards the side of the inner wall of the suction drum. Conduit 20 is connected to a negative pressure source 22 by way of a schematically shown line 21. An air stream is produced as a result in this zone of the suction drum jacket which acts from the outside to the inside. This is schematically indicated by the arrows shown with the broken lines.
As is also shown, a respectively prepared fiber package 24 is disposed in the zone of conduit 20 and Is held on the outside jacket SU of the suction drum by the negative

pressure applied in conduit 20. The detaching process to obtain fiber package 24 will be described below in closer detail.
A separating drum 30 is rotationally movably held below the suction drum 3, which separating drum is provided in its interior with a fixed pipe32. The inner space of the pipe 32 is connected with the negative pressure source 34 by way of a schematically shown line 33. The pipe 32 is provided in the axial direction with a slot 36 which can correspond with air slots 38 which face radially outwardly and are disposed circularly around the tube. The separating drum 30 is arranged in such a way that the slot 36 is sealed off from the ambient environment of the separating drum 30 when no air slot 38 is opposite of the opening 36.
The separating drum 30 is held by way of schematically shown guide rolls 40 in its position, with at least one of the guide rolls 40 being in connection with a drive 42. As seen in the direction of rotation of the separating drum, 30, ejastic nipping elements are fastened to the outside jacket AU behind each of the air slots 38. The function of said elastic nipping elements 44 will be explained below in closer detail.
A doffer 46 cooperates on the outside circumference AU of the separating drum 30, which doffer is provided on its circumference with a clothing 47 (shown partly) for example. The fiber material 50 discharged by the doffer 46 (e.g. in the form of a " nonwoven) is conveyed to a pair of draw-off rollers 51 and conveyed to a downstream further processing stage (not shown).
The mode of operation of said device is described below:

The drafting arrangement 1 is supplied with a sliver 20 for example and drafted in the drafting arrangement. The end E which projects from apron 2 reaches the gap between the circumferential surface SU of the suction drum 3 and the belt 6 which is guided on roller 5. By the rotational movement of the suction drum 3, one of the elastic nipping elements 18 reaches the described zone and nips the end E against the outside surface of belt 6 in the zone of roller 5. As a result of the fact that the circumferential speed of the suction drum 3 is higher than the conveying speed of apron 2, the fibers are pulled out of the end E of the sliver 10 which are nipped between the nipping strip 18 and the belt 6. This leads to a thin fiber package 24 with longitudinally aligned single fibers.
Figs, la through 1c show a schematic representation of the process for forming the fiber package 24. Fig. la shows the end E which is supplied by apron 2. A nip line KL is produced through the nipping strips 18 and the nip line KL is displaced with respect to end E. As is shown in fig. 1b, a thin place D is produced and, following the further displacement of the nip point, a fiber package 24 which is detached from the end E, as is shown in fig. 1c. The head K of the fiber package 24 forms a fiber-end-oriented fiber package, with the short fibers substantially being located in the zone of head K. The clamping effect between the belt 6 and the nipping element 18 on the detached fiber package 24 is maintained during the passage through the rollers 5 and 8, thus ensuring a purposeful further conveyance of the fiber package 24 without any changes to its structure (longitudinally aligned fibers).
Once the fiber package has passed roller 8, it is held by the applied negative pressure in conduit 20 on the surface SU of suction drum 3. The front end K of the fiber package 24 still rests on the nipping strip 1"8. While the shown fiber package 24 is conveyed in the direction towards the separating drum 30, further fiber packages 24 (not shown) are extracted from the end E by the downstream nipping strips 18. The conveyance of the sliver 10 is performed continuously, whereas the draw-off process for producing the fiber packages 24 occurs discontinuously.

Following further transport or further rotation, the indicated fiber package 24 reaches the discharge zone A between the suction drum 3 and the downstream separating roller 30. As a result of the simultaneous rotation of the separating roller 30, a nipping element 40 impinges on fiber package 24, thus producing a nip between the outside jacket SU of the suction drum 3 and the nipping strip 44. The angular position during the operation of the suction drum 3 and the separating drum 30 is chosen in such a way that the nip line produced by the nipping strip 44 is performed at a distance from the front end K of the fiber package 24. Said distance to the head end of the fiber package can be regarded as being equal to the setting distance in the combing machine and can be set by changing the angular position between the drums 3 and 30. Shortly after producing the said nip, the end of the suction slot 38 is in overlap with the opening 36, thus producing an air stream to the inside as a result of the negative pressure in tube 32. As a result, the front end or head K of the fiber package 24 which projects over the nip point of the nipping element 44 is pulled into the suction slot 38. Ail components of the end which project into the suction slot 38 and are not nipped by the nipping element 44 (short fibers) are extracted from the fiber package 24 by the air stream and discharged inwardly into the conduit 32. The negative pressure source 34 is used to discharge from the zone of tube 32 the material carried off to conduit 32.
The fixed disposal tube 32 can be arranged in such a way that any deposited impurities between the fixed part and the rotating part of the separating drum are continuously also sucked off.
In the course of a further rotation of the drum 30, the forward end of the fiber package 24 remains in the slot 38; the rear end is slightly lifted by the occurring centrifugal force. Once said rear end has reached the zone of the adjacent doffer 46, it is grasped by the clothing 47, as a result of which the fiber package 24 is entrained and pulled out of the air slot 38. During said entrainment, the end of the fiber package 24 is placed on the trailing end of a previously drawn fiber package, as a result of which a roof-tile-like connection is produced. The thus formed nonwoven 50 can then be supplied to a downstream pair of draw-off rollers 51 for further conveyance to subsequent processing steps. The representation of special detaching devices for the nonwoven 50 from the

doffer 46 was omitted. Reference is hereby made to respective elements which are already used in the run-out section of a carding machine.
The embodiment shown herein only represents a possible variant to implement the invention. A further variant will be described below.
In fig. 2, a sliver F1 and F2 each is supplied by way of rollers 54 and 55 to the zone of a conveying trough M1 and M2 of a guide part 58. A feed roller 60 and 61 engages in the respective conveying trough M1 and M2.
The guide part 58 is provided between the conveying troughs M1, M2 with an air slot 63 which is provided with an opening 64. This is also shown, particularly in the enlarged representation according to fig. 3, Fig. 4 shows various possibilities as to how this opening 64 can be arranged. The opening in fig. 4a) is provided with a longitudinal slot 66 which extends over the width of the guide part 58. In the representation according to fig. 4b), several adjacently disposed holes 67 are used for the air passage. Fig. 4c) shows a further embodiment, with a larger number of holes 68 being provided for the air passage. In the representation according to fig. 4d), adjacently disposed cross-recessed-like openings 69 are used.
It is certainly possible to provide more combinations and embodiments which can be used for the respective application.
As is shown schematically, the air slot 63 is connected with a compressed air source 71 via a line 70. Above the aperture zone (opening 64 of air slot 63), a nipping element 75, 76 each exert a nipping effect on the downwardly conveyed slivers F1 and F2 and form on the guide part 58 a nip point K1 and K2. The downwardly guided ends of the slivers F1 and F2 are joined below the opening 63 and form a joint free end E1.

As is shown in particular in fig. 3, the air stream which starts out from air slot 63 is directed between the two mutually superimposed ends of slivers F1 and F2 which form a joint end E1. The function of this device will be explained below in closer detail.
. As is also shown in fig. 3, additional air nozzles 77 and 78 which are distributed over the width can be provided in the zone of the ends of the nipping elements 75 and 76, which air nozzles are in connection with an excess pressure source 81 via schematically shown lines 79, 80. Said nozzles 77 and 78 are used to produce an additional compressed air stream in the direction towards the trailing end E1, which air stream can penetrate the end El substantially from the outside to the inside. Said additional compressed air streams ensure that the entire end E1 is completely flowed through with air, so that all components (short fibers, dirt, neps, etc.) which cannot be held back by the nip points K1 and K2 are discharged downwardly by the air stream. Roller 83 is provided with a revolving hollow body 87 which is provided with an opening 89. In the interior of the revolving body 87, a fixed cover 88 is provided which is provided with an opening 90. As is shown schematically, the interior space of cover 88 is provided with a negative pressure source 92 by way of the line 93. This shows that once the openings 89 90 are in overlap, material separated from the end E1 can be sucked off via the interior space of the cover 88, The roller 82 is arranged as a full roller and can be provided with a rubber coating for the draw-off process. A sliver forming unit 95 is disposed below the pair of rollers 85, which sliver forming unit is composed of a revolving suction drum 97 and a rubber-proofed roller 99 which cooperates with the suction drum. A fixed cover 98 is arranged in the interior of the suction drum 97 whose interior space is connected with a negative pressure source 102. In the zone of the nip point 101 between the roller 99 and the suction drum 97 the cover is provided with openings 100. The openings, which allow the suction of ambient air, are shown in the indicated example with a different cross-sectional surface. The cross-sectional surface of the opening 100 is smallest closest to the nip point 101. This means that the suction force on the removed fiber package FP is the smallest in this zone, whereas it becomes larger with gradually increasing cross-section of the openings 100. This is to ensure that the ends of the drawn-off fiber packages FP rest securely on the outside circumference of the suction drum 97. This device allows layering in a roof-tile-like manner the fiber

packages FP which are supplied downwardly step-by-step in such a way that finally a sliver B is formed which can be drawn off downwardly by way of a downstream pair of rollers 104 in order to transfer the same to subsequent collecting devices for example (cans).
As is shown additionally in fig. 3, an advanceable combing element 105 can be provided between the nipping elements 75, 76 and the pair of rollers 85, which combing element is provided with two advanceable combing elements 106, 107. This combing element 105 can be compared with the top comb of a combing machine and then comes into engagement with the free end E1 when a fiber package is drawn off downwardly from said end E1 by way of the pair of rollers 85. This allows to withhold and remove during the draw-off process any short components and also any impurities which have not been completely separated by the air stream. This means that the combing element 105 acts as an additional separating aid.
Fig. 5 shows a further possibility of a sliver forming unit 95 where instead of a suction drum, a revolving conveyor belt 110 is used which is provided with air-permeable openings 111. This is also shown in particular in fig. 6. The conveyor belt 110 is guided via two rollers 112, 113, with one of said rollers being in connection with a drive (not shown in closer detail). An upwardly open conduit 115 is provided on the interior side of the revolving conveyor belt 110 which is connected via a line 116 with a negative pressure source 117. Said conduit 115 is attached in the zone of the conveyor belt in which the fiber packages drawn off by the pair of rollers 85 are layered in roof-tile-like manner in order to form a closed sliver B.
In the representation according to fig. 6 it is shown by the schematically indicated axes A1 and A2 that the axes of the pairs of rollers 85 can also be aligned inclined to the draw-off direction T. This can provide an additional effect with respect to the blurring of the piecing positions.
The mode of operation of the embodiment of figs. 2 through 6 is now explained below in closer detail.

The slivers F1 and F2 which are supplied via rollers 54 and 55 (instead of the slivers it would also be possible to supply nonwovens or webs) reach the zone of the feeding troughs M1 and M2, as a result of which they are grasped by the rollers 60 and 61 and are further conveyed. Below the opening 63 of the guide part 58 the ends of slivers F1, F2 are joined into a single end E1. Once the free end E1 has reached a predefined excess projecting length below the guide part 58, the supply via rollers 54, 55 and the rollers 60 and 61 is interrupted. A mechanism (not shown) is used to displace (swivel) the nipping elements 75 an 76 in the direction towards the guide part 58, which elements form a nip point K1, K2 on the sliver F1 and F2. Thereafter an air impulse is produced via the compressed air source 71 through the opening 64 of the air gap 63 which penetrates the free end El and extracts any unnipped components (e.g. short fibers) from the end E1. As is shown in particular in fig. 3, the air stream, starting out from air slot 63, penetrates the end El in the zone where the two ends of slivers F1 and F2 overlap. As a result of the so-called "Bernoulli effect", the two components of the free end E1 are held together, thus ensuring that the complete fiber material of end El is penetrated by air. In order to further increase the separating effect, additional air impulses can be applied by the nozzles 77 and 78 on the end E1. After ending the blowing interval, the nip points K1 and K2 are released again by retracting the nipping elements 75 and 76. During the blowing process the roller 83 assumes the indicated position, with the opening 89 being disposed opposite of the opening 90 and the separated material being discharged through the openings \with the help of the negative pressure source 92. It would also be possible to provide additional suction devices which are not shown here. As arranged by a double arrow, the guide part 58, including the rollers 54, 55 and 60, 61, can be displaced in the direction towards the pair of rollers 85, so that the tip of the blown-out end El reaches the nip point"between the rollers 82 and 83. It is also possible, instead of the movement of the guide part 58 towards the pair of rollers 85, to displace the pair of rollers 85 in the direction towards the guide part 58 in order to grasp the fibers of the free end El.
Once the end E1 is held in the nip point of the pair of rollers 85, the comb as shown in fig. 3 can be advanced. The opening 89 of the hollow body 87 is now in a position which is opposite of the position as shown in fig. 2. This means that the closed jacket of the

hollow body Is used tor the draw-off process. The pair of rollers 85 is now put into motion and a fiber package FP is drawn off from the end El which is grasped by the nip point of the pair of rollers 85. Said fiber package FP is transferred downwardly to a nip point 101 of the pair of rollers 95 where the released rear end of the fiber package FP comes to rest on the suction drum 97, which is supported by the openings 100 which are in connection with the negative pressure chamber of cover 98. The front end of the fiber package FP is joined with an end still located in the nip point 101 of a previously drawn-off fiber package FP, or it is layered with the same in a roof-tile-like manner.
The thus formed sliver B is discharged downwardly by way of the nip point 101 to a pair of rollers 104 for further conveyance.
The embodiment according to fig. 5 and fig. 6 is applied instead of the pair of rollers 95 and is provided with a revolving and air-permeable conveyor belt 110. The fiber package FP which is supplied downwardly to the pair of rollers 85 is layered on the ends of the previously supplied fiber packages and connected to the same in a roof-tile¬like manner. This process is supported by the application of a negative pressure via conduit 105, as a result of which the free ends and also the formed sliver or nonwoven B are held in a positioned manner on the surface of the conveyor belt 110.
It is also possible to arrange several fiber selection devices above the conveyor belt 106 which all supply the selected fiber material onto the same conveyor belt and join the same into one joint structure.
Fig. 7 shows a further embodiment which is provided with an arrangement similar to the example of fig. 2. Instead of a second supplied fiber structure there is a guide plate 127 which stands opposite to the end E2 of the fiber structure F3.
One or several slivers F3 (or lap, nonwoven, etc.) are conveyed in the direction towards a nip point K3 via the guide part 121 which is provided with a guide trough MS under the influence of a feed roller 120. The nip point K3 is situated at the tapering end of the guide part 121 and is produced by an adjustably arranged nipping element 132. The

adjusting movement of the nipping element 132 is shown schematically with a double arrow.
An air slot 123 is attached in the interior of the guide part whose opening ends below and in front of the nip point K3. The opening can be arranged according to the embodiments shown in fig. 4. The air slot is connected via line 124 with a negative pressure source 125.
It is also possible, as is shown in fig. 3, to provide an additional advanceable combing element 105 in this case too.
A displaceably held plate 127 is attached below the guide part 121 whose front end 122 is provided with a flexible arrangement. A lever 126 acts on said end, which lever is in connection with an adjusting mechanism not shown in closer detail. This lever 126 can be used to move the end 122 to the positions as shown in the dot-dash lines. For the purpose of horizontal guidance of the plate 127 a guide element 128 is provided and in the rear zone of the plate a cylinder 130 acts on the point of articulation 129 which is used for displacing the plate. A suction device 134 is provided above the plate 127 which is used for removing the separated waste material.
A horizontally displaceable pair of rollers 135 is attached adjacent thereto which is provided for drawing off fiber packages from the selected end E2.
As has already been described in the embodiment of fig. 2, a sliver forming unit 137 is - provided downstream ^3f the pair of rollers 135, which sliver forming unit comprises a rotatably held suction drum 138 and a cover 139 arranged in the interior of the suction drum, which cover is provided with openings 140 in the draw-off zone in front of the nip point 144. The interior space of the cover 139 is connected with a negative pressure source 147.

A roller 141 cooperates with the suction drum 138 which can be provided with a rubber coating. The sliver supplied by the suction drum is conveyed further by a pair of rollers 145.
The function of this device is now briefly described below:
The fiber material F3 is conveyed via the feeding trough MS and the feeding cylinder
120 via the zone of the nip point K3. The plate 127 assumes the straight and most
forward position shown in the enhanced print.
Once the excess projecting end of the free end assumes a defined value beyond the nip point K3, the nipping element 132 is displaced in the direction towards the guide part
121 and the fiber material F3 is nipped at the nip point K3. The conveyance was
interrupted in the meantime. The front end of the plate 127 is displaced by way of lever
126 to the above position as shown in the dot-dash line, as a result of which the free
end E3 is also entrained with the plate 127. A compressed air stream is produced by
way of the compressed air source 125 and the air slot 123 which progresses in the
direction of a suction device 134 which has been activated in the meantime.
As a result of the air stream which is guided along the surface of plate 127, the end E2 (as described above) is pulled onto the plate and is blown through completely by the air stream. The short fibers extracted from the end E2 and the other extracted components are carried off via the suction conduit 134. The supply of compressed air is interrupted again and the nipping element 132 is lifted from the guide part 121 again. At the same time, the end 122 is swiveled by way of lever 126 to the downward position (dot-dash • line) and displaced reanwardly via the cylinder 130. This produces sufficient free space, so that subsequently the pair of rollers 135 can be displaced in the direction towards the nip point K3 until the free end E2 is grasped in the nip point of the pair of rollers 135 and is drawn off. This draw-off process is comparable with the detaching process in a conventional combing machine. Once a fiber package has been pulled out of the free end E2 in this way, the pair of rollers is displaced in the direction towards a downstream sliver forming unit 137. Said fiber package is placed there in a roof-tile-like manner on the end of a previously supplied fiber package (piecing process) and joined to the same

in the nip point 144. Tlhereafter the thus formed sliver.B reaches a pair of rollers 145 which supplies the material to a downstream receiving apparatus (can) (not shown). In the meantime the end of plate 127 was conveyed back to the stretched and forward position and the selection and subsequent draw-off process begins anew.
The embodiments shown herein are only exemplary. Further embodiments are possible within the scope of the invention.
The shown devices allow performing a purposeful selection of fibers without requiring the use of large accelerations of mass and reversing movements and with high working speeds.

WE CLAIM:
1. A method for sorting the fibers of a fiber structure (10, Fl, F2) which is supplied to a fiber sorting device (30, 38, 75, 76, 58, 63), characterized in that it comprises the steps of nipping the fiber structure (10, Fl, F2) transversally to its conveying direction in a definite distance from the effective end of the fiber strand; exposing the free end projecting beyond the clamping point with an air flow; extracting and removing from the free end, any non-nipped components such as short fibers, neps, dust etc.
2. The method as claimed in claim 1, wherein the fiber structure (10) is divided prior to reaching the sorting device (30) into individual fiber packages (24) with single fibers which are stretched in the longitudinal direction and are aligned approximately parallel to one another.
3. The method as claimed in claim 2, wherein the fiber packages (24) following successively at a distance from one another are formed by intermittent extraction of fibers from the free end (E) of the fiber structure.
4. The method as claimed in any one of the claims 2 to 3, wherein, as seen in the conveying direction of the fiber package (24), the fiber package is nipped during the sorting process at a predetermined distance from its forward end (K) which is subjected to the air stream.

5. The method as claimed in any one of the claims 1 to 3, wherein the air stream, as seen from the nip point (Kl, K2), is directed towards the free end (El) of the fiber structure (Fl, F2) or fiber package (24).
6. The method as claimed in any one of the claims 1 to 5, wherein the free end (El) which projects beyond the nip point (Kl, K2) is subjected to a suction air stream.
7. The method as claimed in any one of the claims 1 to 5, wherein the free end (El) which projects beyond the nip point (Kl, K2) is subjected to a compressed air stream.
8. The method as claimed in any one of the preceding claims, wherein after the sorting process the nip force is released at the nip point (Kl, K2) and the sorted fiber material is transferred to a downstream sliver forming unit (95) for the formation of slivers.
9. The method as claimed in any one of the claims 2 to 7, wherein the sliver formation is performed by a partial super positioning of the sorted fiber packages (24).

10. The method as claimed in claim 1, wherein at least two fiber structures (Fl, F2) are supplied to the fiber sorting device simultaneously and the ends of the fiber structures are subjected to a common air stream.
11. The method as claimed in claim 10, wherein the ends of the fiber structures (Fl, F2) are joined and air is blown between the ends of the fiber structures, starting out from the zone of the nip points (Kl, K2).

12. The method as claimed in claim 10, wherein at least one additional compressed air stream is produced downstream of the respective nip point (Kl, K2) in the direction towards the free end and onto the outside surfaces of the joined ends (El) of the fiber structures (Fl, F2).
13. An apparatus for the sorting of fibers of a fiber structure (10, Fl, F2) which is supplied by means of feeding means (1, 3, 54, 55, 60, 61, 58) to a fiber sorting device, characterized in that nipping apparatuses (44, 75, 76) are provided which nip the fiber structure (24, Fl, F2) at a distance from its free end (El) and means (33, 34, 36, 38, 63, 70, 71) are present which produce an air stream from the nip point (Kl, K2) to the free end (El) of the fiber structure.
14. The apparatus as claimed in claim 13, wherein means (18, 5, 6) are provided in order to open the fiber structure (10), which is supplied by the feeding means (1), in a step-by-step manner into individual fiber packages (24) with single fibers which are stretched in the longitudinal direction and are aligned parallel with respect to one another, and with means (3) to transfer the fiber packages to a downstream sorting device (30, 38, 75, 76, 58, 63).
15. The apparatus as claimed in claim 14, wherein the feeding means are formed by a drafting arrangement (1) and the means for producing individual fiber packages (24) consists of a rotatably held roller (5) which together with a rotatably held suction drum (3) form a nip point which is opposite of the delivery point of a drafting arrangement (1).

16. The apparatus as claimed in claim 15, wherein the roller (5) is enclosed by a circularly held belt (6) over a partial zone of its circumference, at least in the zone of the nip point.
17. The apparatus as claimed in claim 16, wherein adjacent to the nip point the belt (6) rests on the circumference of the suction drum (3) over a partial section thereof
18. The apparatus as claimed in any one of the claims 15 to 17, wherein the suction drum (3) is provided with elevations (18) which are distributed in a spaced manner on its circumference.
19. The apparatus as claimed in any one of the claims 15 to 18, wherein the drafting arrangement (1) is an apron drafting arrangement.
20. The apparatus as claimed in any one of the claims 15 to 19, wherein a rotatably held separating drum (30) is assigned axially parallel to the suction drum (3) which separating drum is provided with several radially outwardly facing suction slots (38), with the position of the suction slots corresponding to the smallest distance fi-om the outside circumference (SU) of the suction drum (3) with a negative pressure chamber (32) which is fixedly arranged in the interior of the separating drum (30) and is connected with a suction means (34).
21. The apparatus as claimed in claim 20, wherein, as seen in the direction of rotation of the separating drum (30), elastic elevations (44) are provided adjacent to the

respective opening of the suction slots (38) on the outside circumference (AU) of the separating drum (30), which elastic elevations exercise a nipping effect on the outside circumference (SU) of the suction drum in the position of the smallest distance between the suction drum (3) and the separating drum (30).
22. The apparatus as claimed in any one of the claims 20 to 21, wherein means (20, 21, 22) are provided at least in a partial zone between the zone where the belt (6) rests on the outside circumference (SU) of the suction drum (3) and the transfer zone (A) to the separating drum (30) in order to produce a negative pressure in the interior of the suction drum (3).
23. The apparatus as claimed in any one of the claims 20 to 22, wherein a rotatably held doffer (46) is provided axially parallel to the separating drum (30), which doffer touches the outside circumference (AU) of the separating drum (30).
24. The apparatus as claimed in claim 23, wherein the doffer (46) is provided with a clothing (47) on its outside circumference.
25. The apparatus as claimed in claim 13, wherein the fiber sorting device is supplied with at least two fiber structures (Fl, F2) via conveying means (54, 55, 60, 61) and movably held nipping elements (75, 76) are provided for each fiber structure, which elements co-operate with a common guide element (58).
26. The apparatus as claimed in claim 25, wherein at least one air nozzle (63) is provided in the guide means (58) whose opening (64), as seen in the conveying

direction of the fiber structures (Fl, F2), opens downstream of and between the nip points (Kl, K2) and is connected with a compressed air source (71).
27. The apparatus as claimed in any one of the claims 25 to 26, wherein the guide element (58) is provided with mutually opposite guide troughs (Ml, M2) into which a conveying roller (60, 61) used as a conveying means is immersed.
28. The apparatus as claimed in any one of the claims 25 to 27, wherein air nozzles (77, 78) are integrated in the nipping elements in the zone and downstream of the nip surfaces of the nipping elements (75, 76) and are in connection with a compressed air source (81).
29. The apparatus as claimed in any one of the claims 24 to 28, wherein a pair of rollers (85) which forms a nip line is arranged downstream of the nipping elements (75,76).
30. The apparatus as claimed in claim 29, wherein at least one of the rollers (82, 83) of the pair of rollers (85) is provided as a hollow cylinder (87) with outwardly facing openings (89), with the hollow chamber being connected with a negative pressure means (92).
31. The apparatus as claimed in any one of the claims 29 to 30, wherein a sliver forming unit (95) is arranged downstream of the pair of rollers (85).

32. The apparatus as claimed in claim 31, wherein the sliver forming unit (95) is formed by a suction drum (97) and a draw-off roller (99) which co-operates with the suction drum.
33. The apparatus as claimed in claim 32, wherein the interior space of the suction drum (97) is connected with a negative pressure source (102) and covers (98) are provided on the inner side of the suction drum (97) which seal off the interior space against ambient air up to a partial section in front of the nip point (101) between the suction drum (97) and the draw-off roller (99).
34. The apparatus as claimed in any one of the claims 25 to 33, wherein an advanceable combing element (105) is provided between the nipping elements (75, 76) and the pair of rollers.
35. The apparatus as claimed in any one of the claims 29 to 34, wherein the guide means (58) is held displaceably in the direction towards the pair of rollers (85).
36. The apparatus as claimed in claim 31, wherein the sliver forming unit (95) is made of a revolving conveyor belt (110) which is arranged transversally to the discharging direction of the pair of rollers (85).
37. The apparatus as claimed in claim 36, wherein the conveyor belt (110) is provided with air-permeable openings (111) and means (115, 116, 117) for producing a negative pressure are provided at least below the delivery zone on the conveyor belt.

38. The apparatus as claimed in claim 13, wherein at least one guide means (127) is provided which extends along the free end (E2) of the fiber structure (F3) and the fiber structure (F3) is supplied to the fiber sorting device by means of a conveying means (120) which co-operates with a guide element (121).
39. The apparatus as claimed in claim 38, wherein at least one movably held nipping element (132) is provided which co-operates with the guide element (121).
40. The apparatus as claimed in any one of the claims 38 to 39, wherein at least one air nozzle (123) is provided in the guide element (121) whose opening opens downstream of the nip point (K3) between the free end (E2) of the fiber structure (F3) and the guide means (127) and is connected with a compressed air source (125).
41. The apparatus as claimed in any one of the claims 38 to 40, wherein the guide means (127) is formed by a plate which is displaceable in the longitudinal direction.
42. The apparatus as claimed in any one of the claims 38 to 41, wherein the end (122) of the guide means (127) facing the free end (E2) of the fiber material (F3) is flexible.
43. The apparatus as claimed in claim 42, wherein the flexible free end (122) of the guide means (127) is connected with an adjusting device (126).
44. The apparatus as claimed in any one of the claims 38 to 43, wherein suction devices (134) are arranged in the zone of the free end (122) of the guide means (127) which is opposite of the free end (E2) of the fiber structure (F3).

45. The apparatus as claimed in any one of the claims 38 to 44, wherein the nip point
is provided downstream with a displaceable pair of rollers (135).
46. The apparatus as claimed in claim 45, wherein a sliver forming unit (137) is
provided downstream of the pair of rollers (135).

Documents:

in-pct-2001-0444-che abstract-duplicate.pdf

in-pct-2001-0444-che abstract.jpg

in-pct-2001-0444-che abstract.pdf

in-pct-2001-0444-che claims-duplicate.pdf

in-pct-2001-0444-che claims.pdf

in-pct-2001-0444-che correspondences-others.pdf

in-pct-2001-0444-che correspondences-po.pdf

in-pct-2001-0444-che description (complete)-duplicate.pdf

in-pct-2001-0444-che description (complete).pdf

in-pct-2001-0444-che drawings.pdf

in-pct-2001-0444-che form-1.pdf

in-pct-2001-0444-che form-19.pdf

in-pct-2001-0444-che form-26.pdf

in-pct-2001-0444-che form-3.pdf

in-pct-2001-0444-che form-5.pdf

in-pct-2001-0444-che petition.pdf

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Patent Number

215994

Indian Patent Application Number

IN/PCT/2001/444/CHE

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

05-Mar-2008

Date of Filing

28-Mar-2001

Name of Patentee

MASCHINENFABRIK RIETER AG

Applicant Address

Klosterstrasse 20, CH-8406 Winterthur,

Inventors:

#	Inventor's Name	Inventor's Address
1	BROSE, Thomas	EMAIL KLOTI-STRASSE 12a, 8406 Winterthur,
2	CLEMENT, Heinz	In Wannen 12, CH-8406 Winterthur,

PCT International Classification Number

D01G 9/10

PCT International Application Number

PCT/CH99/00385

PCT International Filing date

1999-08-23

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	1766/98	1998-08-28	Switzerland