Title of Invention

AN APRON FOR DOUBLE-APRON DRAFTING SYSTEMS FOR SPINNING MACHINERY

Abstract

The present invention provides a belt for a double-apron drafting system for spinning machinery which comprises a fibre bundling zone, said belt having a plurality of perforations, a first set of perforations being extended crosswise in the direction of fibre transport and a second set of perforations arranged alternately between the first set of perforations, the transverse axis of the first set of perforations being larger than the transverse axis of the second set of perforations, said first set of perforations being transverse condensation holes and second set of perforations being condensation holes.

Full Text

V DRAFnNG EQUIPMENT WTIH SMALL DOUBLE BELTS I The invention relates to drafiing equipment with small double belts for spinning machines with a fiber bundling zone Wiich follows the pair of output rollers and is followed by the pair of delivery rollers according to the introductory clause of claim L Drafting equipment of this type is described in DE 43 23 472. Therein a pneumatic compression device is installed between the pair of output rollers and the pair of delivery rollers, said con^ression device being {provided with a small perforated belt and a suction device extending on the side of the small belt away from the fiber sliver and aspiring air through he fiber sliver. Very good results are achieved with this known device with respect of gathering together and bundling of the fibers, so that a smooth yam with considerably in^roved resistance to tearing is spun It was shown however that the pneumatic compression device has relatively high air consumption. When using the conventional traversing apparatus it may fiirthermore occur that border fibers are no long^ seized secure^ because they are either outside the perforation, or because the negative pressure is not sufficient^ strong to bundle thent An enlargement of the perforation not only requires more air but decreases the gath^ing together of the fibers. Increased negative pressure also required more suction edacity. It is however also important for the obtention of Bniform spinning results that the optimal state of the drafting equipment, in particular of the compression device, be maintained.. In the known device a small belt is used without fabric insert in order to release the fibers at the outlet of the delivery roller v4iich had been sucked into the perforation by their ends. These small belts without fabric inserts do not last long. It is the object of the present invention to avoid the described disadvantages and to improve the compression effect of the known device v^e reducing the suction capacity. The invention is based on the recognition of the tact that orify a relath^el^ short distance is necessary for the bimdling of the fiber sliver, and this independently of the staple length of the fibers. The maintenance of the suction air stream as far as into the area of the nip of the delivery cylinder merely serves to maintain the bundling of the fiber sliver up to the entry into the pair of delivery cylinders. According to the invention the problem is solved by the characteristics of claims 1,6,11,18 and 23 separately or in combination with each other. The shortening of the suction zone (claim 1) results in considerably reduced air consun^tion an^ heightened con^pression effect. FibenE vvhich may have been diverted during transportation are ' again bundled by fiirther compression in the immediateb^ area before the entry of the fiber sliver into the nip of the dcliveiy cylinder. By connecting the perforation openings by one or several grooves (claim 6) a mechanical holding of the bundled fibers is achieved so that the fibers are kept in their bundled position even without suction effect. Furthemiore by providing several grooves, the small belts can be used universal^ with fiber slivers of dififerent thicknesses. i By using perforation openings with dimensions perpendicular to the direction of fiber movement greater than in the direction of fib^ movement (claim 11X the fiber sliver is safely brought together also during traversing. A certain rough gathering together results, so that the perforation can be kept smaller for the actual compression and so that not only savings in air, but also a closer gathering together of the roving is achieved. ID order to always maintain the effect of the pneumatic compression device at an optimal level, it has proved to be necessary to clean it from time to time. This i$ especially necessaiy with a lowered negative pressure. This can be carried out easily by the device according to claim 18. This embodiment makes also automation, e.g. in connection with thread piecing, possible. Finally, according to the characteristics of claims 15 and 16, small belts with long life can be used and reliable release of fibers caught at the outlet torn the delivery cylinder can nevertheless be achieved. The characteristics of claim 23 make it possible to avoid a clogging of the perforation by dust etc. and thereby to avoid lowering of the optimal suction effect. Further details of the invention are described through the drawings, Figs. 1 and 2 show a small belt with a groove, in a top view and cross-section; Figs, 3 and 4 show diflferent embodiments of the small belt with transversal holes, with and without grooves; Fig. 5 shows an embodiment with a groove to lift off the small belt; Fig. 6 shows an embodiment with shortened suction 2X)ne and additional compression; Figs. 7 and 8 show details of Fig. 6 seen from below and in cross-section; Figs. 9 anbl 0 show an embodiment with cleaning device in lateral view and from above; Figs. 11 and 12 show an embodiment of the conqsression device witii two akemately usable DraHing equipment with double belts for spinning machines 'with a fiber bundling zone following the pair of output rollers of the main drafting field and which is followed by the pair of delivery rollers 5 has alreacfy been described con^letely in DE 43 23 472, so that only the improvements according to the invention of this drafting equq}nient are discussed below. Fig. 1 shows the small belt 6 of the pneumatic conpression device which is provided with perforations 61, hereinafter compression holes 61, which are connected to teach other by a groove 62. The groove 62 is drawn greatly enlarged. It is adapted in its width to the mass of fibers to be gathered together by the compression holes 61. The gathered fibers come to lie in the groove 62 which is sized so that it exerts a certain clamping efifect on the fibers. As a result the bundled fibers are held mechanical^ until the are under the nip of the delivery roller 5 so that the suction air stream need be shut off only on the bundling immediately after emergence &om the p^ of output rollers F.O. the drafting equipment. ! Figs. 1 and 2 show only one groove 62 which connects the compression holes 61 with each dther. However several grooves 62, e.g. three, are advantageously placed parallel to each other. Even when more grooves are used, these are always in the area of the compression holes 61, never further out. The width of these grooves 62 is kept so that they are just able to accept the mass of fibers, so that a certain clanging action results. It has been found that several grooves 62, e.g. three (Fig. 4) are better than only one single groove 62» because the small belt 6 can be used more universally. With very fine yams one single groove 62 would be too wide and would not exert any clamping action, and on the other hand too narrow a groove 62 would not be able to receive the mass of thicker yams. If several grooves 62 are used, e.g. three, the fiber mass only enters the central groove for finer yams. The outer grooves remain empty. In this manner sufficient clamping action is achieved however. The grooves 62 are fiirthenmore placed symmetrically with respect to the area of the compression holes 61. Figs. 3 and 4 show small belt 6» 600 where in addition to the compression holes 61, perforation openings 63 are shown, extending fiirther in the direction across the direction of fiber movement than in the direction of fiber movement. By means of these so-called transversal holes 63 the compression device is able to achieve rough con:|)ression of especially wide fiber slivers. Furthermore the fibers are still bundled by these transversal holes 63 when the position of the fiber sliver ahemates as a resuU of traversing movement. Gathering together over a greater width results. The transversal extension of these transversal holes 63 therefore is approximate^ equal to the traversing stroke or to the therein changed position of the fiber sliver relative to the small belt 6. Transversa] holes 63 and compression holes 61 are placed in regular akeraatioa With the small belt 60 in Fig. 3, a transversal hole is alw^Q^s placed between two compression holes. For air consunqstion it is however more advantageous if the number of transversal holes 63 is smaller than the number of compression holes 61. For instance in Fig. 4, Avith the small belt 600, one transversal hole 63 follows every two compression holes 61. In this manner, good compression is achieved with less air consumption and traversing of the fiber sliver. Comprehensive tests have shown that the gathering together of the fiber sliver by the suction air stream, transversally to the conveying direction, begins immediate^ upon emergence from the pair of output rollers, but ends after a short distance. This gathering together is independent of the staple length. Suitable design of the perforation as described above is furthermore &vorabie for the gathering together. It has been shown that the suction zone defined 1^ the groove 41 need not to extend as &r as the delivery cylinder S. Shortening the suction zone furthermore increases the effect of the suction air stream in the shortened area and thereby increases the gathering together of the fiber sliver. Shortening the suction zone even allows for considerable reduction of the suction capacity v^^le the bundling effect remains the same. Fig. 6 shows an embodiment in which the groove 41 in the belt cage 4 extends only over less than one half of the length of the belt cage 4. The groove 41 which is connected to the suction channel 42 is located in the portion of the belt cage 4 which is away fi-om the deliveiy cylinder 5 and is open towards the output cylinder of the drafting equipment. The length of this suction zone is approximately 10 to 25 mm. In this short zone the fiber sliver is Bkesdy gathered together completely. The suction zone can therefore be kept as short as possible to save suction air capacity, i.e. it is only as long as is absolutely necessary for the gathering together of the fibers. With long fiber staples the width of the cylinder nip is greater in function of the staple length. In that case too, the suction zone may not be greater. Following the suction zone, the grooves 62 in the small belt 6 then possibly assume the cohesion or the clamping of the fibers gathered together, as described earlier. In addition, subsequent conpression may also take place between the suction zotie defined by groove 431 and the nip of the delivery cylinder 5. For this purpose a channel 43 is provided which connects the groove 41 to the subsequent compression are before the delivery cylinder 5, Figs 11 and 12 show an alternative embodiment of the compression device, in vAuch two | perforations 61 axKl 61' as well as 63 and 63' are provided. At the perforation 6r, 63', the i perforation openings are additionally connected to the grooves 62. The variants according to Figs. 3 and 4 are combined here, but due to the asymmetrical placement of the groove 410 in the belt cage 40, always only one of the perforation rows is operating at a time. The groove 410 is connected via a suction channel 420 to the exhaust suction which is not showa This embodiment has the advantage that the con^ression device can easily be adapted to different roving thicknesses and material requirements by turning over the small belt 660. The small belt 660 is thereby more flexible in its application than a belt ^vith only one row of perforations. D£ 43 23 472 descnbes that as a result of the suction air stream it happens that fiber ends are sucked through the perforation and are then caught between the small belt 6 and the upper roller S. This leads to annoying interference during spinning because these fibers are unable to follow the direction of the fiber sliver being twisted into a yam. It is therefore desirable to lift the belt6 from the delivery cylinder 6 in the output area in order to prevent this clamping of the fibers. In the above-mentioned DE 43 23 472 this lifting of the belt 6 is efifected through suitable selection of the belt material. A lifting efi^t can however be also achieved by providing a groove int he delivery cylinder 5 under the perfi)ration, so that the belt 6 does not lie on the delivery cylinder 5 at that location. These measures require however special design of the delivery cylinder 5 or also of the belt 6. Furthemiore the belt 6 is less resistant to wear if it lacks a fabric layer, According to the present invention, a fi^e space is created in the run-out of the delivery cylinder 5 by providing a ridge 2 dver v^Wch the belt 6 is guided immediately fo^owing the nip of the delivery cylinder S. The ridge 2 is attached to a holder 21. The ridge 2 is adjustable by adjusting this holder 21. This ridge 2 not only serves to create clearance to prevent the catching of the fiberii, but thanki to the more pronounced deflection of the belt 6, the fibers are more easily detached fi'^m the belt 6, especially "u^en fine yams are spua Peeling of the fibers is avoided in any case, thus resulting in better and more uniform yarn quality. If the suction is operating for a long period of time in the fiber bundling zone, an accumulation of fiber fly and dust in the groove 41 cannot be avoided, so that the operation of the pneumatic con^ression device is gradually affected. The traveling blowers normally used with ring spinning machines cannot be used for satisfactory cleaning in this case because they are only externally eflfective. Disassembly for cleaning of the pneumatic con^ression device is however very expensive. Figs 9 andlO show an embodiment in which a cleaning device for the compression device is provided. A blowing air diannel 45 with a connection piece 44 lets out in the belt cage 4 into the groove 41 across fi-om the outlet of the suction air channel 42. If cleaning is to be carried out, compressed air is introduced through this blowing air channel 45, v^e the negative pressure through the suction air channel 42 is however maintained. It has been shown that the dirt which settles generally in the groove 41 and especial^ at the outlet of the suction channel 42 can be successfiilfy removed in this manner The compressed air is conveyed to the connection piece 44, This can be done manuaUy but also by means of an automatic traveling carriage. In the arrangement of Fig. 10 two compression devices are attached in a pair to a carrier whidi in turn is held in the conventional bearing ann of the drafting equipment on which the upper roller pair of the delivery cylinder 5 is also mounted in the center. To avoid the necessity for the service carriage to recognize in each instance whether the spinning station involved is on the right or on the left side of the bearing arm of the^drafting equipment, the connection pieces 44 and 44* are given identical positions relative to the spinning station. Cleaning advantageously takes place in conjunction with yam breakage repair. When the service carnage is positioned at a spinning station, the identical placement of the connection piece 44 or 44* relative to the spindle ensures that the service carriage ensures that it is able to service the connection piece 44 or 44' without making a distinction. The cleaning device thus not only carries out successful cleaning of the compression device but furthermore can be easily operated by a service carriage. Reduction of the suction effect can occur as a result of dust settling in the perforation. Also burrs at the edge of the perforBtion can cause fibers to get caught on them It has been shown that a deburred perforation operates without problems and without clogging even when the material is very dirty. Such a burr-free perforation is obtained by breaking the edges which have normally burrs as a result of the usual punching process. It is more economical and sin^ler in production to make the perforation by means of a laser ray. V^ith this production process clean and burr-free perforations are produced, and these surprisingly have no teodency to be clogged by dust or catching fibers. REFERENCE LIST 2 Ridge 21 Ridge holder 3 Carrier 4, 40 Belt cage 5 Delivery roDer 41,410 Groove 42.42', 420 Suction channel 43 • Channel 44,44' Connection piece 45 Blo^vn-ai^ channel 6,60,600, 660 Small belt 61, 6V Compression holes, perforation openings 62 Groove 63, 63' Transversal holes, perforation openings 1. An apron for double-apron drafting systems for spinning machinery, comprising a fibre bunching zone which joins the couple of front rollers of the main drafting zone and is followed by a couple of delivery rollers wherein a pneumatic condenser device is arranged between the couple of front rollers and the delivery device, which has a perforated apron and a suction device which extends on that side of the apron which faces away from the fibre structure (FB) and draws in air through the fibre structure, characterized in that the apron (60; 600) has a series-arranged perforation apertures (61; 63) with perforation holes (61) being provided at the same extension crosswise to the direction of fibre transport and in the direction of fibre transport and perforation holes (63) being provided the extension of which crosswise to the direction of fibre transport is larger than that in the direction of fibre transport. 2- The apron according to claim 1, characterized in that the cross extension of these transverse holes (63) is made to match the traversing lift. 3. The device according to any one of claim 1 or 2, characterized in that the transverse holes (63) and condensation holes (61) are arranged in a regularly alternating way. 4. The device according to claim 3, characterized in that the number of transverse holes (63) is smaller than is the number of condensation holes (61). 5. The device according to claim 4, characterized in that two condensation holes (61) each are followed by one transverse hole (63). The apron according to one or more of claims 1 to 5, characterized in that the perforation of the apron is without any burr. The apron according to claim 6, characterized in that the perforation has broken edges. The apron according to any one of claim 6 or 7, characterized in that the perforation is made by means of a laser. The apron according to one or more of claims 1 to 8, characterized in that the perforatioi} apertures (61) are joined to each other by a flute (62) in the direction of fibre travel. The apron according to claim 9, characterized in that a plurality of flutes are arranged in parallel with each other in the area of the perforation apertures (61). The apron according to one or more of claim 9 or 10, characterized in that the width of the flutes (62)and/or their number is made to match the mass of the fibres. The apron according to claim 9, characterized in that three flutes (62) are arranged in parallel with each other. The device according to any one of claim 11 or 12, characterized in that the flutes (62) are arranged in symmetry with the area of these condensation holes (61). The apron according to one or more of claims 1 to 13, characterized in that the apron (660) has two rows of perforations (61, 61*; 63, 63') which alternatively can be associated with a groove (410) that is asymmetrically disposed in the suction device (40). 15. An apron for double-apron drafting systems for spinning machinery substantially as herein described with reference to the accompanying drawings.

Documents:

940-che-2003-abstract.pdf

940-che-2003-claims duplicate.pdf

940-che-2003-claims original.pdf

940-che-2003-correspondence others.pdf

940-che-2003-correspondence po.pdf

940-che-2003-description complete duplicate.pdf

940-che-2003-description complete original.pdf

940-che-2003-drawings.pdf

940-che-2003-form 1.pdf

940-che-2003-form 26.pdf

940-che-2003-form 3.pdf

940-che-2003-form 5.pdf

940-che-2003-other documents.pdf