|Title of Invention||
A DRAW-IN OR FEED ROLLER
|Abstract||The invention provides a draw-in roller clothing in form of a wound wire, with the wire having a root section and a leaf section projecting up from the root section and the leaf section being formed with triangular teeth. The leaf section is provided with a (leaf) height of less than 2 mm and preferably between 1.0 and 2.0 mm. According to the currently prevailing production practice, the tooth height is preferably lower than the leaf height.|
|Full Text||The invention relates to a draw-in roller or to a roller with such a clothing. The invention comprises a suitable wire shape for the stated purpose.
State of the art
The present invention is based on the state of the art according to DE-A-19708261. The latter specification describes a clothing which is designed primarily for use on the feed roller of a carding machine. Said clothing is designed to fulfill two partial tasks, namely:
1. to ensure the conveyance of the material to the licker-in, and
2. to enable a precise detection of fluctuations in the material.
In order to fulfill these tasks it was necessary to develop new types of teeth. In order to ensure a sufficient conveying effect a tooth shape with a back angle of close to 90° was chosen. (Note: It seems that this tooth is used to convey material „with the back".) The precise detection of fluctuations in the material is to be promoted by the use of teeth (and therefore tooth gaps) with a lower height. Although this is not mentioned specifically as a partial task, the achievement of a large open space around each tooth is to help avoid battings. Although the specification also shows a fiber tuft feeder (tower feeder; fig. 4), it is not obvious which specific advantages would speak in favor of using the new clothing in the fiber tuft feeder since the draw-in roller shown in the fiber tuft feeder does not perform any detection of fluctuations in material.
The present invention is based on the object of providing a clothing which is adapted ideally to the draw-in roller (also known as „feed roller") in a fiber tuft feeder of a carding machine. In this connection two partial aspects are relevant, namely
- the capability of the draw-in roller to further convey material „from the standstill", on
the one hand, and
- the capability to ensure the forwarding of said material to the downstream opening
roller on the other hand in order to thus prevent battings.
The use of a clothing according to the invention at other places in the spinning mill is not excluded. This clothing is specially designed for the fiber tuft feeder of the carding machine. The requirements placed on the fiber tuft feeder differ at least in the respect from the other applications in cotton spinning in that the material is opened relatively badly at this place; large changes in density must be expected in particular. Moreover, the speed of the draw-in roller is often relatively low as compared to the speed of the feed roller in the carding machine per se. At a diameter of the draw-in roller of approx. 180 mm the speed is in the range of 700 to 1300 r.p.m. for example. In connection with the fiber tuft feeder it is also necessary to consider certain recent developments, especially
- the relatively high throughput of material which a modern card fiber tuft feeder needs to cope with; a modern cotton carding machine is often designed (for example) for a production of more than 100 kilograms of sliver per hour, which requires the supply of a respective fiber quantity through the tower;
- the use of a feed roller/feeding trough unit instead of a pair of feed rollers;
- the increasing tendency to demand narrower settings between trough and roller, and
- the increasing popularity of the so-called „synchronous feeding" which protects the fiber material, but makes the complete combing by the downstream opening roller more difficult, which may cause an increased tendency towards the formation of batting for certain fiber assortments.
It is obvious therefrom that partly contradictory requirements are demanded. It has been noticed, however, that it is possible to fulfill these requirements without having to develop a principally new form of tooth (also known as tooth geometry), i.e. the invention is based on the optimization of a known triangular tooth shape as is offered for example for the doffer (Hollingsworth GmbH) and/or the draw-in roller (Graf und Cie. AG).
The terminology used in this description is explained below in closer detail by reference to fig. 4. It corresponds principally to that of ISO 5234 as well as the description of the swift clothing in the technical article „Entwicklungen auf dem Gebiet der Kardengarniturenkonstruktion" (Developments in the Field of Card Clothing Construction) in the magazine „textil praxis international", September 1994, pp. 551
through 560, and especially pages 552 and 555 (Author - Dipl. Ing Bernhard T. Bocht.) An additional term is used in this description, however, namely the „leaf height" which is defined here as total height less dedendum.
Principally, the invention provides a feed roller clothing in form of a rolled wire, with the wire having a root section and a leaf section projecting from the root section and the leaf section being formed with triangular teeth, characterized in that the leaf section has a (leaf) height of less than 2 mm and preferably between 1.0 and 2.0 mm. According to current production practice the tooth height is usually lower than the leaf height.
The wedge angle of each tooth is preferably 30° to 120°, with a value of approx. 80° being appropriate. The front angle is preferably -20° to -60°, with a value of approx. -40° being appropriate. This angle is enclosed between the tooth profile conveying the material and a line perpendicular to the base of the wire. The preferred shape of tooth or tooth geometry is based on an isosceles triangle. The tooth shape or tooth geometry can be chosen asymmetrically, however. The tooth profile which is less steep can be used to convey the fiber material in the usual conveying direction. The drive for the feed roller can also be reversible, so that the steeper tooth profiles may also be used under certain circumstances for conveying material, e.g. in order to discharge the feed roller or for removing foreign material which has come between the trough and the feed roller.
The tooth spacing is preferably between 3.0 and 5.0 mm. It is chosen preferably larger than the leaf height.
The root width is 2.0 to 4.0 mm for example and is preferably also chosen larger than the leaf height when the wire coils are wound next to one another.
Embodiments of the invention are shown below by reference to the enclosed drawings, wherein:
Fig. 1 shows a side view of a carding machine (of a „cotton card") for processing short staple fiber (e.g. shorter than 60 mm);
Fig. 2 shows a side view (on an enlarged scale) of a fiber tuft feeder for a carding machine according to fig. 1;
Fig. 2A shows a detail of fig. 2 in order to represent tine conditions at tine transfer
location between draw-in roller and opening roller; Fig. 3 schematically shows (on an enlarged scale) a feed or draw-in roller according
to the present invention for use in an arrangement according to fig. 2;
Fig. 3A shows an alternative tooth shape;
Fig. 4 shows a schematic representation for explaining various terms in connection with saw-tooth clothings, with said figure consisting of the partial figures of 4A, 4B and 4C;
Fig. 5 shows schematically in a side view (as seen in the direction of arrow P in fig. 6) a piece of wire of a saw-tooth clothing for use in a feed or draw-in roller according to fig. 3;
Fig. 6 shows the same piece of wire in a cross-sectional view, and
Fig. 7 shows a modified tooth geometry. ,
Card 10 according to fig. 1 corresponds to the doctrine of EP-A=866153S-(or the further developments in EP-A-989213 and/or in figs. 9 through 22 of WO-A-99/50486J. This type of carding machine is only mentioned here as an example. The invention can also be used in combination with a conventional card cross section (e.g. according to fig. 1 of WO-A-99/50486). The structure of the fiber tuft feeder 12 according to fig. 2 corresponds principally to the structure according to EP-A-894^78, In the embodiment according to fig. 2, the cleaning stations of EP-A-894,878 were omitted. It is understood that the invention can also be used in a fiber tuft feeder which is equipped with cleaning stations according to EP-A-894,878.
In the card according to fig. 1 the direction of material flow runs from right to left, with the actual flock feeding means (fig. 2) not being shown in fig. 1. The fiber material supplied by the flock feeding means is supplied in form of a batting to the carding machine 10, forwarded by a feed roller 14 to a licker-in module 16 (also known as taker-in module), transferred to a cylinder 18 (also known as swift) and further opened and cleaned by cooperation of the cylinder with a set of revolving flats of a revolving flat unit 20. The flats of the set of revolving flats are guided by a suitable drive system of the revolving flat unit by deflection pulleys 24 along a closed path (in synchronicity with or in
the opposite direction to tine rotational direction of the cylinder). Fibers from the card web disposed on the cylinder are removed by the doffer 26 and formed into a sliver (not shown) in an outlet section 28 consisting of various rollers. Said card sliver is deposited in a transport can in cycloidal windings by a can coiler (not shown; see for example EP-A-99/58749).
The arrangement according to fig. 1 is only mentioned as an example. The features yet to be described can also be used in other types of cards or carding machines, e.g. large-scale machines which are suitable for the production of nonwovens (bonded fiber fabrics). The revolving flat unit 20 comprises flat rods 22, whereof only individual rods are shown schematically in fig. 1. The currently used arrangement of revolving flats in a conventional carding machine (e.g. C51 carding machine of the applying company) comprises more than one hundred flat rods. The rods are held at their ends by continuous belts 30 and thus moved against the rotational direction of the cylinder or in synchronicity with said direction of rotation. Examples for such devices can be found in EP-A-753 610. The revolving flat unit 20 in fig. 1 only requires approx. 70 to 90 flat rods, whereof approx. 20 - 35 stand simultaneously in the working position with respect to cylinder 18. Each flat rod 22 preferably comprises a clothing carrier in the form of a hollow profile, as is also shown in US 5,542,154 for example. The clothing strip attached to said carrier is preferably configured as a flexible („semi-rigid") clothing, i.e. the strip comprises a flexible body which is fastened to the carrier, and individual tips, whereof parts are embedded in the body.
The revolving flat arrangement can be replaced by fixed flats, e.g. according to principles which are explained for example in US-B-3,604,062; US-B-3,044,475 and US-B-3,858,276.
The part of the cylinder circumference which is covered in a revolving flat card by the revolving flat arrangement can be designated as main carding zone. The major part of the carding work is performed in this zone. Additional working elements are provided in other zones of the cylinder 18, however, in order to produce a further carding effect. The portion of the cylinder circumference between the licker-in module 16 and the revolving flat unit 20 is designated here as pre-carding zone; the part of the cylinder circumference between the revolving flat unit 20 and the doffer 26 as post-carding zone, and the part of the cylinder circumference between the doffer 26 and the licker-in module 16 as lower carding zone. In the pre-, post- and lower carding zone of the
carding machine it is possible to provide additional processing elements. The provision of such elements in the lower carding zone is preferably omitted.
In the pre-carding zone there is space for at least one additional segment 32 with a dirt separation knife (e.g. according to EP-A-848091 and/or WO-A-99/61688). In the post-carding zone there is at least one additional segment 32 and at least one carding rod 34 which can be formed similar to the flat rods. Several additional segments can be provided both in the pre-carding zone as well as in the post-carding zone. The cylinder 18 is covered by cover elements 36. A suitable covering can be found in EP-B-431 482 or EP-B-687 754 and in our EP-A-790 338.
The working width of cylinder 18 is relevant for all other working elements of carding machine 10, in particular for
- the revolving flats, (or fixed flats in a fixed flat carding machine) which must card the fibers evenly over the entire working width together with the cylinder,
- the feeding system which needs to consistently ensure an evenly distributed stream of fibers to the cylinder over the entire working width, and
- the doffer system which must consistently lift off fibers evenly from the cylinder over the entire working width.
The diameter of the cylindrical surface of cylinder 18 is also an important value for the machine. In combination with the working width, the diameter determines the working surface of the cylinder. It is undesirable to exceed a predetermined fiber density per unit of surface. According to EP-A-866153 the cylinder diameter is between 700 mm and 1000 mm, with a diameter of between 750 mm and 850 mm being chosen preferably. The preferred diameter range is 800 to 820 mm. Moreover, the carding machine according to fig. 1 preferably has a working width of greater than 1300 mm, e.g. 1500 mm.
The lower carding zone is large enough to allow the attachment of the following devices, namely:
• suitable guide elements (only indicated schematically) at the transfer location from the licker-in module to the cylinder,
• the „tongue" Z (e.g. according to EP-A-790 338) at the transfer location between cylinder and doffer,
• a clothing grinding apparatus (e.g. according to US 5,355,560), with said apparatus not being relevant for the function of the carding machine. It can be regarded as a facultative option.
The solution according to fig. 1 comprises in the licker-in module 16 three licker-ins according to EP-A-989213. Only one licker-in can be used. The (first) licker-in cooperates with the feed roller 14 which receives the fibers from a lap which is formed by the fiber tuft feeder (cf. fig. 2). The fiber tuft feeder 12 according to fig. 2 comprises an upper part 40 (a feeding chute, which is shown only partly in fig. 2) as well as a lower chute part 42 (back-up chute). Fiber flocks from the lower chute part 42 are conveyed by two conveying rollers 44 as the batting and fonwarded to the feed roller 14 of the carding machine 10.
A feeding apparatus 48 is disposed between the upper chute part 40 and the lower chute part 42, which feeding apparatus supplies the flocks to an opening roller 46. Such apparatuses are generally known. According to the invention as described in EP-A-810309, cleaning elements should be attached to the opening roller 46 in order to form a cleaning module which allows substantial changes to the upstream sections of the installation. In the solution according to fig. 2 a cleaning module was omitted for the sake of simplicity. Principally, the feeding apparatus 48 and the opening roller 46, in combination with the adjacent part of the housing of the chute, should be converted in such a way that a „fine cleaner" is thus obtained. The adaptation requires elements on the circumference of the opening roller 46 which allow the separation of impurities.
The feeding apparatus 48 constitutes a „nip feeding system" for the opening roller 46. Said nip feeding system consists of a feed or draw-in roller 50 and a trough 52. Such arrangements are also known at other places in spinning preparation, e.g. in the supply to a fine cleaner (example: see EP-B-419915) and in the aforementioned feed roller of the carding machine per se (example: see EP-A-926274). The embodiment of the invention still to be described has been designed for use in the filling box, but it is not limited to this field of application.
In the detail according to fig. 2A, the directions of rotation of the rollers 50 and 46 have also been indicated by an arrow each. This figure also shows that the effective nip line between the trough 52 and the draw-in roller 50 can be moved very close to the transfer location to the opening roller 46. The illustrated arrangement of the directions of rotation leads to a so-called ..synchronous feed", which means that the material combed out by roller 46 from the nip line is removed by trough 52. In the case of the so-called ..feed in opposite direction", the roller 46 rotates in the opposite rotational direction, so that the combed material is guided between trough 52 and the roller 46. The (illustrated) synchronous feed leads to a more careful treatment of the fibers in comparison to feed in the opposite direction. The fiber material does not separate cleanly from the draw-in roller 50 when using synchronous feed, which means that the material is guided back again to the upper portion of the chute on the surface of the roller 50. The risk of the formation of batting is thus increased.
The draw-in roller 50 according to fig. 3 comprises a cylindrical carrier body 54 and a clothing which is formed by a wire length 56 which is wound about a body 54. The well-known term of „saw-tooth clothing" is also used for this clothing. The intended shape or geometry of the teeth will be explained below by reference to figs. 5 and 6. The illustration according to fig. 3 is only schematic, because only one single „clothing winding" (a single winding of wire 56 about body 54) has been shown in order to clearly explain the principle of the clothing and to enable a comparison with DE-A-19708261. As is clearly shown in fig. 3, the teeth 58 of a clothing according to this invention are formed as ,.triangular" teeth, with the triangles preferably being isosceles. Each tooth can be formed with a tip as is shown in fig. 3. The tips of the teeth can also be blunt, as has been schematically indicated with AS (on an enlarged scale) in fig. 3A for modified teeth 58A.
Concerning the terminology which is used in this description, reference is hereby made to fig. 4. Special attention must be given in particular to the definition of the ..negative angle" in fig. 4B. This definition is to be understood in such a way that when the wedge angle includes the imaginary perpendicular line which forms the front angle, the front angle is still measured from said perpendicular line, with the value thus measured being rated as a ..negative angle". A tooth shape with such a negative ..front angle" is shown in fig. 4B with the broken line, with said line extending in the front profile (or conveying profile) of the tooth. The assumed normal direction of conveyance has also been indicated in fig. 4B by means of an arrow. It is assumed here that the tooth profile which
defines the front angle is also used for conveying material in the normal direction of conveyance (this assumption is not obtained clearly from the aforementioned ISO standard, but it corresponds to the practice employed for designations by the applicant company). According to this definition the front angle always becomes smaller than 90° and it is enclosed between the material-conveying tooth profile and a line which extends through the tip of the tooth and stands perpendicular to the base of the wire.
The wire 56 which forms the clothing according to fig. 3 is shown in the stretched form in figs. 5 and 6. It principally comprises a root section 60 and a leaf section 62 projecting up from the root section 60, with the actual teeth 58 being formed in the leaf section 62. In addition to the terminology outlined in fig. 4, the term „leaf depth" BT (fig. 5) is used in this description.
The leaf depth BT of a wire according to the invention is chosen appropriately smaller than 2.5 mm, with the preferred range being 1.3 to 1.7 (e.g. 1.5) mm. The leaf depth BT also limits the tooth depth, for which purpose it is not necessary to define any preferred range herein. The tooth depth is chosen according to current conventional production processes slightly smaller than the leaf depth BT. This conventional practice can be maintained for wires according to the present invention.
The tooth spacing P is appropriately more than 3 mm, with the preferred range being 3 to 5 mm. It is possible for example to choose a value of 4 mm at a leaf depth of 1.5 mm. The tooth spacing P is in any case preferably 1.5 times the leaf depth, or even more than that.
The root width b1 is preferably 2.0 to 4.0 mm. When neighboring windings are placed directly next to one another, as is indicated with the broken lines in fig. 5, the root width b1 also defines the „lead" (cf. DE-A-19708261 and ISO 5234, Table 4). As is shown by the latter specification, however (fig. 5b in DE 19708261), the lead can also be influenced by other means (in fig. 5D of DE 19708261 by a spacer wire; the clothing wire can also be wound in a spiral groove in the carrier body, so that in this case the slope of the groove defines the lead). The lead is preferably at least 3.0 mm, but can be limited to 5.00 mm. When the wire is placed in a groove, it may be possible to work with a smaller root width, but it is preferably not less than 1 mm. Even when the wire windings are placed next to one another, they can also be provided with a so-called interlinkage. Since the interlinkage of clothing wire is well-known and does not deal directly with the invention, no further discussion is made thereof.
The arrangement according to fig. 6 assumes teeth which are formed as isosceles triangles. With such an arrangement it is irrelevant in which direction the fiber material is to be conveyed by the one or other tooth profile. The wedge angle B (see fig. 4) can be chosen in the range of 30° to 120°, with the preferred value being between 70° and 100° (e.g. 80°). The front angle a (see fig.4) is appropriately (-20°) to (-60°), with the preferred value being (-40°).
The tooth geometry for a wire according to the invention is not limited to the isosceles triangle. An alternative is shown in fig. 7 which shows that the tooth can be formed in a triangular way, but asymmetrical. The front angle a of such a tooth can be -60° for example, namely at a wedge angle of approx. 70°. The normal direction of conveyance is shown in fig. 7 with the arrow, i.e. the less steep profile 64 is usually used for the conveyance of the fiber material. The steeper profile 66 (of the „tooth back") can be used for conveying the material when the drive motor (not shown) for the draw-in roller is reversible, as has already been explained in the introduction.
The invention is particularly important where one must expect that the material supply to the carding machine needs to be stopped temporarily. The draw-in roller is to reliably „thread in" the material from the chute section 40 to the feeding apparatus during the new start-up. For this purpose, the clothing must show a certain amount of „aggressiveness" which is ensured by the chosen tooth geometry. An aggressive clothing exerts „retaining forces" on the material, however, which can lead to problems in separating the material from the draw-in roller. A clean separation is therefore very important as the risk of battings is otherwise increased. Since this risk also depends on the fiber assortment, the clothing needs to be chosen in such a way that no batting is produced on the draw-in roller with the material to be processed.
1. A draw-in or feed roller (50) with a clothing in the form of a wound wire, with the wire (56) having a root section (60) and a leaf section (56) projecting up from the root section and the leaf section being formed with triangular teeth, and the leaf height (HT) defined as total height (h1) minus root height (h2) being less than 2.5 mm wherein the front angle a, which is enclosed between the conveying flank and a line perpendicular to the base of the wire, of each tooth is -20° to -60° and the wedge angle p of each tooth is 30° to 120°.
2. The draw-in or feed roller (50) as claimed in claim 1, wherein the tooth shape corresponds to that of an isosceles triangle.
3. The draw-in or feed roller (50) as claimed in any one of the preceding claims, wherein the tooth spacing is between 3.0 and 5.0 mm
4. The draw-in or feed roller (50) as claimed in any one of the preceding claims, wherein the tooth spacing is chosen larger than the leaf height
5. The draw-in or feed roller (50) as claimed in any one of the preceding claims, wherein the root width (bl) is greater than the leaf height (BT).
6. The draw-in or feed roller (50) as claimed in any one of the preceding claims, wherein the root width (bl) is between 2.0 and 4.0 mm.
7. The draw-in or feed roller (50) as claimed in any one of claims 1 to 5, wherein the
wire has a root width (bl) of at least 1 mm so that it can be inserted in a groove during
8. The draw-in or feed roller (50) as claimed in any one of the preceding claims,
wherein the leaf height (BT) is less than 2.0 mm especially between 1.0 mm and 2.0
mm, preferably between 13 mm and 1.7 mm.
9. The draw-in or feed roller (50) as claimed in any one of the preceding claims with
the exception of claim 2, wherein the geometry of the tooth is formed as an
asymmetric triangle, wherein the less steep flank is used in the feeding direction.
10. The draw-in or feed roller (50) as claimed in any one of the preceding claims,
wherein the pitch of the wire is between 3.0 and 5.0 mm.
11. The fiber tuft feeder with a feeding apparatus (48) in order to supply fiber material
to an opening roller, consisting of a draw-in or feed roller (50) and a feeding trough
(52), wherein the draw-in or feed roller is constructed as claimed in any one of claims
DATED THIS 27 DAY OF JULY 2001
|Indian Patent Application Number||619/MAS/2001|
|PG Journal Number||17/2008|
|Date of Filing||27-Jul-2001|
|Name of Patentee||MASCHINENFABRIK RIETER A G|
|Applicant Address||KLOSTERSTRASSE 20 CH-8406, WINTERTHUR,|
|PCT International Classification Number||D01G 15/88|
|PCT International Application Number||N/A|
|PCT International Filing date|