GB2073792A

GB2073792A - Raised Yarn

Info

Publication number: GB2073792A
Application number: GB8108879A
Authority: GB
Original assignee: Institute Po Obleklo I Textil
Current assignee: Institute Po Obleklo I Textil
Priority date: 1980-04-02
Filing date: 1981-03-20
Publication date: 1981-10-21
Also published as: DE3012929A1; YU69781A; ES8206682A1; FR2479858B1; GR74809B; DE3012929C2; HU185862B; IT8148153A0; IN154110B; IT1142385B; JPS56148933A; AU6877081A; ES500787A0; FR2479858A1; CH655959A5

Abstract

A method and apparatus for producing a raised yarn from a yarn composed of at least two threads of different thicknesses having a false twist. The false twisted yarn (5) is fed to an abrasive surface (9, 15), where it undergoes a raising operation, the abrasive surface being fixed or moving more slowly than the speed of supply of the false twisted yarn. <IMAGE>

Description

SPECIFICATION Method and Apparatus for Producing a Raised Yarn This invention relates to a method and apparatus for producing raised yarn.

A method is known for raising yarns with or without loop structure, produced by a conventional process on ring frames, and on ring effect twisting machines. The previously produced effect yarns in loops are subjected in two twisting operations to spoling and to raising. During raising, the (effect) yarn is wound off from spools, covers a cylindrical drum which rotates at a peripheral speed of 20 to 500 m/min, and by means of a guiding rod it is taken up from the cylindrical surface to be wound in skeins or on a spool. The raising is effected by a drum, which is covered by a wire cloth (card) or another similar abrasive surface. The drum with the cloth rotates at a speed exceeding by several times the speed of the yarn i.e. the speed of the carding device is higher than the speed of movement of the yarn.

A basic draw-back of this method lies in that there are necessarily several separate operations, and a higher speed of the carding device than the speed of the yarn. However, the higher speed of the carding device imposes higher operational costs, and the characteristics of the produced yarn is typical for the yarn in which the fibres and threads are with twist.

The present invention has been developed with a view to utilising the high linear speed of the yarn during raising, but without the necessity to drive a carding device at a higher speed than the speed of the yarn.

According to the invention, there is provided a method of producing a raised yarn from a yarn composed of at least two threads of different thicknesses and having a false twist, comprising feeding the yarn to a yarn-raising device at a predetermined speed relative to abrasive surface of the raising device, in such a way as to undergo a raising operation as the yarn passes along the surface, the abrasive surface being fixed or moving more slowly than the speed of the yarn.

To carry out the method, an abrasive surface may be provided immediately after a device for fastening a false twist e.g. after a hollow spindle which carries a fastening thread, or a nozzle for air texturing, through which the false twisted threads pass. This abrasive surface can be disposed on a continuous conveying belt with translational motion, or it may be fastened to the cylindrical surface of a slowly rotating drum. It is also possible for the abrasive surface to be fixed and/or to move only periodically.

It is typical for yarn produced by a method according to the invention, that the raised fibres are made up of false-twisted threads.

Advantageously, the invention may be applied to raise yarn in a continuous process of yarn production. The yarns may be raised at a speed of 40 to 600 m/min, depending upon the manner of fastening the false twist.

A method according to the invention allows the raising of also previously produced yarn of the afore-mentioned composite type. In this case, it is possible that the feeding speed for winding can exceed 600 m/min. However, there can be raised smooth yarns, as well as "effect" yarns with loop structure. The yarns produced are characterised by a high fill factor, for use in knitting and weaving.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic illustration of apparatus for producing a raised yarn; Figure 2 is a plan view of the apparatus shown in Figure 1; Figure 3 is a plan view of an alternative construction for part of the apparatus shown in Figure 1; Figure 4 illustrates a structure of a raised yarn without loops; Figure 5 illustrates a structure of a raised yarn with loops; and Figure 6 illustrates the structure of a raised yarn after air texturing for fastening of a false twist.

Referring now to Figure 1 of the drawings, there is shown an apparatus for producing a raised yarn from a yarn composed of at least two threads of different thicknesses, and having a false twist, in which the yarn is fed to a yarnraising device at a predetermined speed relative to an abrasive surface of the raising device in such a way as to undergo a raising operation as the yarn passes along the abrasive surface. As will be evident from the following description, the abrasive surface is fixed, or is arranged to move more slowly than the speed of supply of the yarn.

The apparatus comprises a pair of feed rolls 1 arranged to supply a filament, threaded or mixed bundle 2 to a hollow spindle 4, in which the threads comprising the bundle 2 are falsetwisted.

The threads composing the bundle 2 can be made-up from staple fibres by means of a drawing apparatus, as well as from multi-filament fibres. There are also possible different combinations of the aforementioned fibre types.

The bundle 2 may also be formed only by a single thread of staple fibres.

A fastening thread 3, which is wound off the hollow spindle 4, fastens the false twist of the thread bundle. Alternatively, although not shown, the false twist may be applied by means of air texturing in manner known per se. As a result, a yarn 5 is formed having loops, which then is passed over an abrasive surface 9 by means of a pair of draw-off rolls 10. As the fibres of the yarn 5 come into contact with the abrasive surface 9, there is cause a tearing and pulling-up of fibres from the components forming the bundle 2. In this case, a taking-up of fibres from loops 8 takes place. The abrasive surface 9 moves usually at a speed of 0.1 to 15 m/min in a direction opposite to that ofthe supply of the yarn 5. As shown in Figures 1 and 2, the abrasive surface 9 is provided on an endless conveyor belt, and the yarn 5 moves generally longitudinally of the belt.

An alternative arrangement for an abrasive surface is shown in Figure 3, in which an abrasive surface 1 5 is provided on an at least part cylindrical surface provided on a drum 23.

Preferably, the drum 23 is arranged to rotate, and the yarn 5 extends along the abrasive surface through a contact angle, about the longitudinal axis of the drum, of between 0 and 1800.

Any suitable arrangement is provided to impart the necessary false twist to the yarn, which is arranged immediately upstream of the abrasive surface 9 (Figures 1 and 2) or 1 5 (Figure 3).

Immediately upstream of the conveying belt 22 (on which the abrasive surface 9 is arranged), there is provided a lateral transfer device 7, which is arranged to displace the yarn 5 transversely with respect to the abrasive surface 9. A small guide shaft 6 is arranged immediately upstream of the device 7, and in conjunction with the drawoff rolls 10, the yarn 5 is fed to the abrasive surface, and raised yarn is wound onto a spool 12 by winding apparatus 11. The conveyor belt 22 is supported from below by an arcuate bar 24.

Returning to Figure 3, thread-guides 13 and 14 are arranged at the upstream and downstream ends respectively of the drum 23, and these are arranged to operate out of phase with each other in order to achieve variable angle of contact of the yarn 5 with the abrasive surface 1 5. Thereby, there is avoided the need to provide a changeover apparatus which changes the position of the yarn 5 over the abrasive surface. Upon alteration in the tension in the yarn 5 (by variation in the operation of the guides 1 3 and 14), there is caused a change in the contact path of the yarn 5 with the abrasive surface.

Referring now to Figures 4 to 6, there are shown different structures of raised yarn. In Figure 4, there is shown a yarn without loops, which comprises a thread 1 6 made-up of staple fibres having a thickness from 20 to 1000 Tex, which is thoroughly twisted with a thread 17, of thickness from 5 to 7.5 Tex. The fibres of the thread 1 6 are subjected to raising by the apparatus.

In the case of a yarn with loops, as shown in Figure 5, a main thread 1 8 is false-twisted with a thread 20 of staple or multi-filament fibres. The length of th read 20 is greater than that of thread 18, and it forms loops 20a, which are fastened to the thread 1 8 during thorough twisting together with the fastening thread 1 9, or without thread 1 9 with air texturing.

In the case of yarns with loops for raising, there are obtained thicknesses of yarn from 64 to 2000 Tex. The thickness of the main thread 18 is from 1 6 to 80 Tex, while the thickness of the fastening thread 19 is from 5 to 10 Tex. The fibres of the loops 20a are also subjected to raising, which after tearing form the raised yarn with fibres 21 (see Figs. 5 and 6). In the case of yarns with loops 20a which are fastened by means of air texturing to the main thread 18, they are raised by raising the filament threads 21.

While the invention is primarily concerned with method and apparatus for producing a raised yarn from a yarn having a false twist, it should be understood that the invention is also applicable to the production of a raised yarn from a yarn without a false twist.

New or Amended Claims: 1. A method of producing a raised yarn from a yarn composed of at least two threads of different thicknesses, comprising feeding the yarn to a yarn-raising device at a predetermined speed relative to an abrasive surface of the raising device, in such a way as to undergo a raising operation as the yarn passes along the abrasive surface, the abrasive surface being fixed or moving more slowly than the speed of the yarn.

New Claims or Amendments to Claims Filed On 29.6.81 Superseded Claims 1

Claims

1. A method of producing a raised yarn from a yarn composed of at least two threads of different thicknesses and having a false twist, comprising feeding the yarn to a yarn-raising device at a predetermined speed relative to an abrasive surface of the raising device, in such a way as to undrergo a raising operation as the yarn passes along the abrasive surface, the abrasive surface being fixed or moving more slowly than the speed of the yarn.

2. A method according to claim 1, in which the yarn moves transversely along a cylindrical abrasive surface through a contact angle, measured about a longitudinal axis of the cylindrical abrasive surface, of between 0 and 1800.

3. A method according to claim 1 or 2, in which the yarn is composed of one or more false twisted threads of staple or multi-filament fibres, having the same or different lengths in untwisting, after they are fastened by thoroughly twisting with a fastening thread.

4. A method according to claim 3, in which the false twisting is carried out by means of air texturing or false twisting techniques known per se.

5. A method according to claim 1, in which the yarn moves longitudinally at a given speed along an endless abrasive surface which is moving in an opposite direction at a considerably slower speed than said given speed.

6. A method according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

7. Apparatus for carrying out a method according to claim 1 and comprising: means for applying a false twist to the yarn; an abrasive surface arranged to be engaged by the false-twisted yarn so as to produce a raised yarn by carding; and means for feeding the false twisted yarn to the abrasive surface at a predetermined speed relative to the abrasive surface in such a way that the yarn moves along the abrasive surface to undergo a raising operation, the abrasive surface being fixed or being movable at a slower speed than the speed of the yarn.

8. Apparatus according to claim 7, in which said means for applying a false twist comprises a hollow spindle or a nozzle for air texturing.

9. Apparatus according to claim 7 or 8, in which the abrasive surface is fixed, or is attached to an endless movable conveyor.

10. Apparatus according to claim 7 or 8, in which the abrasive surface is provided on an at least part cylindrical surface.

11. Apparatus according to claim 10, in which said at least part cylindrical surface is provided on a drum which is preferably rotatable.

1 2. Apparatus according to claim 7 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

13. A raised yarn produced by a method or apparatus according to any one of the preceding claims.