GB2105375A - Thread feed in textile machines - Google Patents

Abstract

Threads 1 are fed at constant initial tension through thread reserve 17 to a textile machine with constant or varying thread consumption, e.g. a warp knitter. When reserve 17 is full, bars 15, 16 are closed to stop the threads, reserve 17 is diminished by the machine, and beam 8 is lowered to form reserve 24. The machine delivers a pulse to open bars 15, 16. Beam 8 is raised, and thread reserve 24 is thrown into depleted reserve 17. Thread not required from reserve 24 is taken up in pre-reserve 2. <IMAGE>

Description

SPECIFICATION Method and device for thread feed on textile machines The invention relates to a method and a device for thread feed, especially for feeding bands of threads, on textile machines, for example weaving and warp-knitting machines, which work in the thread material simultaneously or variously according to the pattern selection and require a certain constant initial tension force, dependent upon the kind of material, for the thread processing. The invention is usable on textile machines for the production of either singledivision or multi-division goods.

From technical and patent literature many devices and apparatuses for the supply of threads on textile machines are known in which the threads coming from thread supply packages are fed, for example singly by means of rotating thread storage and delivery devices, or in bands of threads by means of feed rolls around which threads loop fully or partially, to a thread processing station.

Thus for example warp turning thread delivery devices with delivery and idle rolls, friction thread feeders in which the threads are conveyed by friction caused between drive and friction wheels, and band thread feeders in which the threads are placed ready individually for intermediate storage on a rotary or drum reserve and drawn off axially with a speed independent of the speed of thread feed according to the thread consumption of the machine, are known.

All these methods and apparatuses possess a series of disadvantages, for example possibility only of uniform thread withdrawal from ail packages and uniform thread consumption, possibility only of delivery of single threads or thread groups, which greatly limit the field of use of the thread feed devices for textile machines. It is also disadvantageous that constant thread tension and thread withdrawal from the thread supply packages with maximum tautness and positiveness are not guaranteed. A further disadvantage consists in the fact that, especially when threads with rough surfaces are supplied, by reason of the protruding fibres and knot ends, especially in the case of rotating delivery rolls and friction thread feeders, coiling occurs due to the threads lying closely side by side.It also proves disadvantageous that the delivery rolls around which threads loop give only a limited aid to delivery as a result of the sliding friction of the threads, and for example in the case of poor makeup of cross-wound packages the threads become taut, which leads to defects in the grey cloth.

Either coiling or taut threads cause stoppage times on textile machines, which are detrimental to productivity. Furthermore in some cases the production of the known thread feed devices is very expensive in cost and time.

For example in GDR Pat. Sp. No.136,861 there is described a device for feeding threads on textile machines which feeds a plurality of threads to a thread working station with constant tension throughout, even in the case of varying thread consumption. While in fact this device, by the arrangement of thread brakes on each thread, evens out the different thread tensions, a thread withdrawal from the thread supply package with maximum tautness and positiveness is not guaranteed by reason of the action of sliding and adhesion friction forces on the delivery rolls. A further disadvantage of this device consists in that it is possible to work only threads with smooth surfaces.Threads with rough surfaces, where protruding fibres are characteristic, as for example in spun yarns, can be worked only conditionally if at all, because coiling then frequently occurs, leading in the end to defects in the grey cloth and increased stoppage times of the machine. It further has a disadvantageous effect that due to the uniform and slow withdrawal from the thread supply packages, for example when accumulations occur, the thread does not become drawn and taut, and thus the knock-off device brings the machine to a halt. The same occurs if the requisite thread draw-off forces are greater than the existing sliding friction forces on the supply rolls.

It is the aim of the invention to guarantee a thread withdrawal from thread supply packages with maximum tautness and positiveness and a secure thread feed to the thread processing station of a textile machine, to avoid coiling, especially in the working of spun yarns, and thus to reduce the defects in the grey cloth produced on textile machines and the stoppage times of the machines, and to extend the field of application for textile machines.

The problem of the invention consists in developing a troublefree and reliable, universally usable method for the thread supply on textile machines with associated device, without the use of rotating thread feed rolls around which threads loop wholly or partially, rendering possible problem-free feed of all thread materials.

The present invention is characterised in that threads coming from thread supply packages are withdrawn discontinuously by means of a thread drawing device according to a control programme, the threads are fed by a thread shut-off and guide device to a thread reserve and then to the thread processing station. By a pulse triggered after filling of the reserve the threads are blocked before the thread reserve by means of the thread shut-off and guide device and at the same time drawn by means of the thread drawing device from the thread supply packages, and a thread store is produced.After thread drawing has taken place the blocking of the thread supply to the thread reserve is released by a pulse issuing from a textile machine, the thread drawing device is moved back into its initial position and the produced thread store is drawn at the same time into the thread reserve. After the filling of the reserve the operation is controlled in constantly repeating manner.

The drawing of the thread advantageously takes place in a vertical direction to the thread feed plane. The drawing and blocking of the threads are here preferably controlled electromechanically.

The method according to the invention will be carried out preferably with a device consisting of a thread drawing device, a thread shut-off and guide device and a thread reserve which are arranged between the thread supply packages and the thread processing station, which are followed and preceded as appropriate by known thread knockoff devices.

The thread drawing device is advantageously formed by a draw beam and deflector rods with guide reeds, arranged for movement vertically in relation to the thread feed plane. According to a preferred form of embodiment the draw beam consists of a U-section girder, perforated strip and deflector rods.

The thread shut-off and guide device expediently consists of a movably arranged shutoff and guide bar and a stationarily arranged shutoff and guide bar.

The thread reserve is formed preferably by deflector rods with guide reeds and a wire bow fittable on to each thread, with which bows a guide rod is associated.

According to one advantageous form of embodiment the shut-off and guide bars are made toothed in themselves or in groove form.

For the purpose of holding the threads taut and to avoid entanglement of the threads with one another a thread pre-reserve is advantageously arranged before the thread drawing device and is formed by a deflector rod with guide reed, the deflector rod with guide reed of the thread drawing device and a wire bow fittable on to each thread, with which a guide rod is associated. This thread pre-reserve serves at the same time to accommodate the thread store not required by the thread reserve. It is here necessary that the tension force exerted upon the threads in the thread pre-reserve by the wire bows should be significantly less than the tension force acting upon the threads in the thread reserve.

According to a preferred form of embodiment the movement of the draw beam and of the thread shut-off and guide device takes place pneumatically.

In the production of multi-division cloth it is expedient to arrange several devices staggered in the thread running direction and one above the other, which devices can be mechanically connected with one another.

According to a final feature of the invention the controlling of the device takes place preferably by means of limit switches, an adjustable time relay and an adjustable pulse counter.

The invention is to be explained in greater detail below with reference to a drawing, wherein:- FIGURE 1 shows a lateral elevation of the thread feed device, FIGURE 2 shows a block circuit diagram of a control system for a thread feed device, FIGURE 3 shows a variant of embodiment of the draw beam, FIGURE 4 shows a variant of embodiment of the thread shut-off and guide device.

As illustrated in Figure 1 , threads 1 coming from thread supply packages are fed to a thread drawing device 7 by way of a thread pre-reserve 2, which is formed by deflector rods with guide reeds 3; 4, a wire bow 5 resting on each thread 1 and a guide rod 6 associated with the wire bows 5.

The thread drawing device 7 consists essentially of a draw beam 8 arranged for vertical movement in relation to the thread feed plane, which beam, as may be seen in Figure 3, consists for example of a U-section girder 9, a perforated strip 10 and deflector rods 1 1; 12 secured on the legs of the U-section girder 9, and with which beam there are associated the deflector rod with guide reed 4 of the thread pre-reserve and a further detlector rod with guide reed 1 3. The threads 1 are guided through the openings of the perforated strip 10 of the draw beam 8, illustrated in Figure 3, and then run through a thread shut-off and feed device 14 which, as shown by Figure 4, consists of a movably arranged shut-off and guide bar 1 5 and of a non-displaceably arranged shutoff and guide bar 1 6. The threads 1 are then fed to a thread reserve 1 7 which is formed by deflector rods with guide reeds 18; 19, a wire bow 20 resting on each thread 1 and a guide rod 21 allocated to the wire bows 20 and serving at the same time as stop, and then they pass to the thread processing station.

The controlling of the thread feed devices takes place according to Figure 2 as follows, Figure 1 being partially incorporated into the explanation.

Commencement is made from the situation where, as may be seen from Figure 1, the thread reserve 1 7 is filled. That means that the wire bows 20 resting on the individual threads 1 are situated in the lower position and the draw beam 8 of the thread drawing device 7 stands in the upper position.

After the thread reserve 17 is filled, according to Figure 2 the thread shut-off and guide device 1 7 is actuated pneumatically through an adjustable time delay 22 and blocks or clamps fast the through-passing threads 1. After blocking has taken place the draw beam 8 is moved, by means of a limit s witch 23, pneumatically vertically in relation to the thread feed plane into the lower position, whereby the threads 1 are drawn from the thread supply packages and at the same time a thread store 24 is formed (see also Figure 1).

During this time the thread store in the thread reserve 1 7 simultaneously diminishes as a result of the continuous working of the threads 1 in a textile machine 25, for example a warp knitting machine. At the same time the textile machine 25, after each machine revolution, actuates a limit switch 26 which is followed by an adjustable pulse counter 27 which counts each contact given by the limit switch 26 and for example each time after 5 min -1 delivers a pulse which triggers the opening of the thread shut-off and guide device 14. Thus the blocking of the threads 1 is released and the thread feed to the thread reserve 1 7 is liberated.With the opening of the thread shut-off and guide device 14 a limit switch 28 is actuated, the contact of which has the effect that the draw beam 8 moves back into its initial position or into the upper position and the occurring thread store 24, as visible in Figure 1, is drawn into the thread reserve 1 7 by the tension forces acting upon the threads 1 through the wire bows 20, which tension forces are substantially greater than the tension forces acting upon the threads 1 in the thread pre-reserve 2. In this action the thread store 24, not required by the thread reserve 1 7 by reason of the varying working-in of the threads 1 in the thread processing station of the textile machine 25, is taken up again by the thread prereserve 2.

As soon as the thread reserve 17 is filled again, in accordance with Figure 2 by means of the adjustable time relay 22 the thread shut-oHf and guide device 14 is closed, the threads 1 are clamped fast and the draw beam 8 is moved into the lower position again, whereby the threads 1 can be drawn at the same time from the thread supply packages. In the meantime the textile machine 25 has again completed 5 min -1 and the thread shut-off and guide device 1 4 is opened again in the described manner, the draw beam 8 is moved into the upper position and the thread reserve 1 7 is filled. Then this operation is repeated afresh.

The method according to the invention with the associated device has the advantage that a reliable and trouble-free thread feed to the textile machine is guaranteed and any coil formation due to rotating feed rolls as utilised hitherto is precluded. At the same time as a result of the jerking thread drawing a satisfactory withdrawal of the treads from the supply packages and a secure thread feed to the thread processing station of the textile are guaranteed. Thus the stoppage times of the machine can be substantially reduced. It is a further advantage that all kinds of material, even spun yarns, can be used, so that a wide field of application concerning thread feed becomes possible.

The invention is further distinguished by its universal usability on textile machines.

It is also advantageous that a better and problem-free separation is possible between textile machine and supply creel, in accordance with the existing space conditions.

Claims (14)

1. Method for thread feed on textile machines with constant or varying thread consumption, in which the threads coming from thread supply packages are fed with constant tension and a specific initial tension force to the thread processing station, characterised in that threads (1) coming from thread supply packages are drawn off discontinuously by means of a thread drawing device (7), according to an appropriate control programme, the threads (1) are fed through a thread shut-off and guide device (14) to a thread reserve (17) and then to the thread processing station, the threads (1) are blocked before the thread reserve (1 7) by means of the thread shut-off and guide device (14) buy a pulse triggered after the filling of the reserve and at the same time are drawn by means of the thread drawing device (7) from the thread supply packages, after thread drawing has taken place the blocking of the thread feed to the thread reserve (17) is released by a pulse issued by a textile machine (25), the thread drawing device (7) returns into its initial position and the produced thread store (24) is drawn at the same time into the thread reserve (17) and after the filling of the reserve the operation is controlled in a constantly repeating manner.

2. Method according to Claim 1, characterised in that the thread drawing takes place in a vertical direction in relation to the thread feed plane.

3. Method according to Claim 1, characterised in that the thread drawing and the thread blocking are controlled electro-mechanically.

4. Device for carrying out the method according to Claim 1, characterised in that between the thread supply packages and the thread processing station, which are respectively succeeded and preceded by known thread knock-off devices, there are arranged a thread drawing device (7), a thread shut-off and guide device (14) and a thread reserve (17).

5. Device according to Claim 4, characterised in that the thread drawing device (7) is formed by a draw beam (8), arranged for movement vertically in relation to the thread feed plane, and by deflector rods with guide reeds (4; 13).

6. Device according to Claim 5, characterised in that the draw beam (8) consists of a U-section girder (9), a perforated strip (10) and deflector rods (11; 12).

7. Device according to Claim 4, characterised in that the thread shut-off and guide device (14) consists of a movably arranged shut-off and guide bar (15) and of a non-displaceably arranged shutoff and guide bar (16).

8. Device according to Claim 4, characterised in that the thread reserve (1 7) is formed by deflector rods with guide reeds (18; 19) and a wire bow (20) for fitting on each thread (1), with which a guide rod (21) is associated.

9. Device according to Claim 7, characterised in that the shut-off and guide bars (1 5; 16) are made toothed in themselves or in groove form.

10. Device according to Claim 4, characterised in that before the thread drawing device (7) there is arranged a thread pre-reserve (2) which is formed by a deflector rod with guide reed (3), the deflector rod with guide reed (4) of the thread drawing device (7) and a wire bow (5) which can be fitted on each thread (1), with which a guide rod (6) is associated.

11. Device according to Claim 10, characterised in that the tension force exerted by the wire bows (5) upon the threads (1) in the thread pre-reserve (2) is significantly less than the tension force acting upon the threads (1) in the thread reserve (17).

12. Device accoridng to Claim 4, characterised in that the draw beam (8) and the thread shut-off and guide device (14) are moved pneumatically.

13. Device according to Claim 4, characterised in that several devices are arranged staggered in the thread running direction and one above the other and are connected mechanically with one another.

14. Device according to Claim 4, characterised in that controlling takes place by means of limit switches (23; 26; 28), an adjustable time relay (22) and an adjustable pulse counter (27).