GB2242913A

GB2242913A - Yarn feed device

Info

Publication number: GB2242913A
Application number: GB9007438A
Authority: GB
Inventors: William Ewart Alan Shelton
Original assignee: Alan Shelton Ltd
Current assignee: Alan Shelton Ltd
Priority date: 1990-04-03
Filing date: 1990-04-03
Publication date: 1991-10-16
Also published as: ITMI910837A0; GB9007438D0; JPH04228659A; IT1245269B; DE4110604A1; ITMI910837A1

Abstract

A yarn feed device comprises a rotatable member (13), an endless flexible element (14) which passes around the rotatable member (13) and around at least one further member (12) disposed closely adjacent to the rotatable member (13), said members being disposed within the periphery of the endless flexible element (14), and means (18) operative to feed the yarn into a nip formed between the rotatable member (13) and the endless flexible element (14) from a position also within the periphery of the endless flexible element (14). The device may be driven by a further endless belt (B). The means (18) formed as tubing may adopt a positive feed position (A), a second position (A') for placing the yarn on the member (13) below the region of the endless element or a third position (A'') bypassing the feed device. Second tubing may feed a second yarn to the further member (12). <IMAGE>

Description

1 1 Title: Yarn Feed Device This invention relates to a yarn feed device.

At present, two different types of yarn feed device are in wide usage. Firstly, there is the type wherein a flexible belt drives a plurality of free-running rollers spaced around the periphery of a yarn processing machine (e.g. a knitting machine), and individual yarns are driven by being passed through a nip between each roller and the belt. Secondly, there is the type wherein a yarn is wrapped several times arounda rotatable, driven capstan and the feeding takes place due to the friction between the yarn and the peripheral surface of the capstan.

The first type of device suffers from the disadvantage that the feed on the yarn is not very positive. It is therefore possible that a high peak of tension in the yarn (e.g. caused by the yarn becoming entangled at the supply cone) can pass to the knitting point, causing the yarn to break at that point"and producing a fault in the knitted fabric. Accordingly, it is necessary to provide a "pull down" detector to stop the machine in the event of there being abnormal tension in the yarn.

2 This particular difficulty is solved by the second type of yarn feed, where the drive on the yarn is much more positive. However, other problems are created instead. For example, the feed device is of a relatively complicated construction and is rather more difficult to thread up. Also, the engagement of successive wraps of the yarn on the capstan gives rise to a "shredding" effect, which causes significant amounts of lint to be shed from the yarn. It is therefore necessary to provide rotating fans on the processing machine to prevent build-up of lint on the feed devices.

It is an object of the present invention to obviate or mitigate these problems and disadvantages.

According to a first aspect of the present invention, there is provided a yarn feed device comprising a rotatable member, an endless flexible element which passes around the rotatable member and around at least one further member disposed closely adjacent to the rotatable member, said members being disposed within the periphery of the endless flexible element, and means operative to feed the yarn into a nip formed between the rotatable member and the endless flexible element from a position also within the periphery of the endless flexible element. In this way, it can be arranged that the yarn is held in the nip for a substantial angle around the rotatable member, giving rise to a very positive feeding action.

Preferably, the or each further member is also rotatable.

Advantageously, there is only one such further member of substantially the same diameter as the rotatable member.

In a particular embodiment, the further member or at least one of the further members is rotatable, and the yarn feed device also comprises means operative to feed a second yarn into a nip formed between said further member and the endless flexible element, from a position also within the periphery of the endless flexible element.

Conveniently, the rotatable member comprises first and second axial regions, the endless flexible element engages the first axial region only and control means is provided to move the yarn selectively between the first axial region where the yarn is driven and the second axial region where it is not driven.

Desirably, the control device includes tube means from whose end the yarn passes to the feed device, and the tube means is movable between positions wherein its end is respectively aligned with the first and second axial regions of the rotatable member.

- 4 The tube means may comprise a first, relatively fixed tube and a second tube in sliding engagement with the first tube.

Preferably, the yarn passes from the feed device to an end of a third tube which is spaced from the end of the first tube, and the second tube is also movable into a position wherein it bridges the space between the ends of the first and second tubes.

The end of the tube means can have an axial slot through which the yarn passes, the slot being arranged to obstruct the passage of knots, slubs or the like greater than a predetermined size. Desirably, the slot is generally V-shaped.

Advantageously, the rotatable member and the endless flexible element are driven by a further endless flexible element which also drives a plurality of similar yarn feed devices. In one arrangement, the further endless flexible element passes around the periphery of the rotatable member, and the first-mentioned endless flexible element is frictionally engaged between the further endless flexible element and the rotatable member. In another arrangement, the further endless flexible element engages a member which rotates with the rotatable member. In a still further arrangement, the further endless flexible element engages a 1 - 5 member which rotates with the further member or one of the further members.

According to a second aspect of the present invention, there is provided a yarn processing machine including a plurality of yarn feed devices driven in synchronism with operation of the machine, each yarn feed device comprising an individual endless flexible element which is in frictional engagement with at least two rotatable members and whose periphery encompasses the points of entry and exit of the yarn, the yarn being passed through a nip between the endless flexible element and one of the rotatable members.

In a preferred arrangement, each yarn feed device is operative to feed two such yarns, each yarn being passed through a nip between the endless flexible element and a respective one of the rotatable members.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of a yarn processing machine; Figure 2 is a part-sectional side view of a yarn feed - 6 device according to the present invention which forms part of the yarn processing machine; Figure 3 is a schematic sectional view along the line 3-3 in Figure 2; and Figures 4 and 5 are similar views of modified yarn feed devices, also according to the present invention.

Referring first to Figure 1, there is shown a yarn processing machine (such as a knitting machine) having a plurality of yarn feed devices F spaced around its periphery. The feed devices F are driven in synchronism with operation of the machine by an endless belt B which is common to all of the feed devices.

One of the feed devices F is shown in detail in Figures 2 and 3, it being understood that the remaining feed devices are similar thereto. The illustrated yarn feed device comprises a body 10 which is secured to a mounting ring 11 of the yarn processing machine. Depending from the body 10 are two rotatable pulleys 12 and 13, and an endless flexible belt 14 passes around these pulleys and frictionally engages the same. Although not specifically illustrated, means is provided on the body 10 to enable the distance between the pulleys 12,13 to be adjusted so that the belt 14 can be suitably tensioned. The pulley 12 - 7 is of substantially the same axial dimension as the belt 14, while the pulley 13 is somewhat wider and has a first axial region 15 which is engaged by the belt 14 and a second axial region 16 which is not so engaged.

A yarn 17 is fed to the device through a length of tubing 18 which passes through the body 10 and whose end portion 19 is positioned between the pulleys 12 and 13, i.e. within the periphery of the belt 14. After leaving the tubing 18, the yarn 17 passes through a nip formed between the outer circumference of the pulley 13 and the inner circumference of the belt 14, and then enters a further length of tubing 20 for passage towards the processing machine. The tubing 20 is secured to a bracket 21 which extends from the body 10 and its end portion 22 is axially aligned with, but spaced from the end portion 19 of the tubing 18.

Slidably engaged with the tubing 18 is a further tube 23 which can be moved vertically between a first position (indicated at A) wherein its end is aligned with the axial region 15 of the pulley 13, a second position (indicated at A') wherein its end is aligned with the axial region 16 of the pulley 13, and a third position (indicated at All) wherein it engages the end portion 22 of the tubing 20 and thus bridges the space between the tubes 18 and 20.

Movement of the tube 23 between its first and second 1 positions causes the yarn 17 to be moved between a driven condition wherein it passes between the pulley 13 and the belt 14 as aforesaid, and a non-driven condition wherein it simply passes around the axial region 16 of the pulley 13. In its third position, the tube 23 enables the yarn to be blown completely through the tubing 18 and 20 during setting up of the machine: thereafter, the tube 23 can be lifted by an operator, and a loop of yarn can be taken out and threaded around the pulley 13.

Although not shown, the end portion 19 of the tubing 18 (or alternatively the end of the tube 23) can be provided with an axial slot through which the yarn 17 passes, the slot being of such a width as to block the passage of knots or slubs greater than a predetermined size. The slot is preferably V-shaped with its width decreasing away from the end proper of the tubing 18, so as to facilitate initial threading of the yarn into the slot.

In use, a plurality of feed devices of this type are secured in spacedapart relation to the mounting ring 11 of the processing machine, and the aforementioned endless belt B is frictionally engaged with the exterior of the belt 14 where 'this passes around the pulley 13: the belt 14 is thus sandwiched between the belt B and the pulley 13.

11.

9 In a modified construction (as shown in Figure 4), drive is transmitted from the belt B by frictional engagement with a further pulley 25 which is mounted on top of the body 10 and which rotates with the pulley 12. In an alternative arrangement, the pulley 25 can be mounted for rotation with the pulley 13 instead of the pulley 12.

Figure 5 shows a further modified construction in which the pulley 12 takes the same form as the pulley 13, and i which a further set of tubes (referenced 1P, 20' and 23') is provided to guide a second yarn 17' through a nip formed between the pulley 12 and the endless belt 14. This particular device can thus be used to drive two yarns, instead of having to provide separate feed devices for this purpose, and therefore represents an economy in construction. In this arrangement, each of the pulleys 12 and 13 is provided with an annular rib 26 to prevent the belt 14 from riding off the axial regions 16. It is found that the presence of this rib has no detrimental effect on the transfer of the yarn from one axial region to the other.

The yarn feed devices described with reference to Figures 2 to 5 are advantageous in that a very positive feed is exerted on the yarn 17 by virtue of the relatively large angle of contact between the yarn and the nip between the 0 belt 14 and the pulley.being approximately 180 in the 9 illustrated arrangements. This in turn comes about because the points of entry and exit of the yarn are disposed (in plan) between the pulleys 12 and 13 and within the periphery of the belt 14. This can be seen to particular advantage in Figure 3. At the same time, the yarn is not subjected to any shredding effects such as are experienced in the aforementioned "multiple wrap" type of feed devices, and therefore generation of lint is minimised. Furthermore, the device is of relatively simple construction and is compact in size, particularly in its width, so that the spacing between neighbouring devices on the mounting ring 11 can be reduced. It is also a fairly simple operation to thread yarn through the device, particularly in comparison with the "multiple wrap" type of feed.

In the above examples, the invention has been described with reference to a pair of pulleys 12 and 13. However, it is possible that a larger number of pulleys can be used, all encompassed by a common belt 14: for example, three pulleys could be used in a triangular disposition. In this case, the angle of contact of the yarn with the nip between the pulley and the belt will be correspondingly reduced, 0 and it is considered that substantially 90 of such contact is the minimum for effective operation of the invention.

1 1 11

Claims

1. A yarn feed device comprising a rotatable member, an endless flexible element which passes around the rotatable member and around.at least one further member disposed closely adjacent to the rotatable member, said members being disposed within the periphery of the endless flexible element, and means operative to feed the yarn into a nip formed between the rotatable member and the endless flexible element from a position also within the periphery of the endless flexible element.

2. A yarn feed device according to Claim 1, wherein the or each further member is also rotatable.

3. A yarn feed device according to Claim 1 or Claim 2, wherein there is only one further member which is of substantially the same diameter as the rotatable member.

4. A yarn f eed device according to any one of the preceding claims, wherein the further member or at least one of the further members is rotatable, and the yarn f eed device further comprises means operative to feed a second yarn into a nip formed between said further member and the endless flexible element, from a position also within the periphery of the endless flexible element.

5. A yarn feed device according to any one of the preceding claims, wherein the rotatable member comprises first and second 12 axial regions, the endless flexible element engages the first axial region only and control means is provided to move the yarn selectively between the kirst axial region where the yarn is driven and the second axial region where it is not driven.

6. A yarn feed device according to Claim 5, wherein the control device includes tube means from whose end the yarn passes to the feed device, and the tube means is movable between positions wherein its end is respectively aligned with the f irst and second axial regions of the rotatable member.

7. A yarn feed device according to Claim 6, wherein the tube means comprises a f irst, relatively f ixed tube and a second tube in sliding engagement with the first tube.

8. A yarn feed device according to Claim 7, wherein the yarn passes from the feed device to an end of a third tube which is spaced from the end of the f irst tube, and the second tube is also movable into a position wherein it bridges the space between the ends of the first and second tubes.

9. A yarn feed device according to any one of Claims 6 to 8, wherein the tube means has an axial slot through which the yarn passes, the slot being arranged to obstruct the passage of knots, slubs or the like greater than a predetermined size.

10. A yarn feed device according to Claim 9, wherein the slot is V-shaped.

1 13

11. A yarn feed device according to any one of the preceding 1 claims. wherein the rotatable member and the endless flexible element are driven by a further endless flexible element which also drives a plurality of similar yarn feed devices.

12. A yarn feed device according to Claim 11, wherein the further endless flexible element passes around the periphery of the rotatable member, and the first-mentioned endless flexible element is frictionally engaged between the further endless flexible element and the rotatable member.

13. A yarn feed device according to Claim 11, wherein the further endless flexible element engages a member which rotates with the rotatable member.

14. A yarn feed device according to Claim 11, wherein the further endless flexible element engages a member which rotates with the further member or one of the further members.

15. A yarn processing machine including a plurality of yarn feed devices driven in synchronism with operation of the machine, each yarn feed device comprising an individual endless flexible element which As in frictional engagement with at least two rotatable members and whose periphery encompasses the points of entry and exit of the yarn. the yarn being passed through a nip between the endless flexible element and one of the rotatable members.

14

16. A yarn processing machine according to Claim 15, wherein each yarn feed device is operative to feed two such yarns. each yarn being passed through a nip between the endless flexible element and a respective one of the rotatable members.

17. A yarn feed device substantially as hereinbefore described with reference to the accompanying Figures 2 and 3.

18. A yarn feed device substantially as hereinbefore described with reference to the accompanying Figure 4.

19. A yarn feed device substantially as hereinbefore described with reference to the accompanying Figure 5.

saj002 Published 1991 at The Patent Office. Concept House. Cardifr Road. Newport. Gwent NP9 IRH. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point. Curnifelinfach. Cross Keys. Newport. NP1 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.