GB2378188A

GB2378188A - Adjustable yarn tensioning and clamping device

Info

Publication number: GB2378188A
Application number: GB0118459A
Authority: GB
Inventors: John Dalton Griffith
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2001-07-28
Filing date: 2001-07-28
Publication date: 2003-02-05
Anticipated expiration: 2021-07-28
Also published as: DE10234451A1; GB2378188B; BE1015203A5; GB0118459D0

Abstract

A yarn tensioning and clamping arrangement comprises an integral yarn guide arm and movable clamping plate 22 formed from a resilient material such as spring steel. The movable arm 22 has a yarn guide eye 42 and may be adjustably biased against a fixed clamping plate 21 by adjustable nut 30.

Description

The present invention relates to a yarn tensioner, in particular but not

exclusively, a yarn tensioner for regulating tension of yarn pulled from 5 individual yarn packages on a creel.

The creel may be of the type used for feeding yarns to a loom such as a Wilton loom.

lo According to one aspect of the present invention there is provided a yarn tensioner including a static yarn clamping plate co-operating with a movable yarn clamping plate, biasing means for biasing the movable clamping plate into clamping abutment with the static clamping plate, a yarn guide arm extending from the movable clamping plate, the guide arm Is having a yarn guide eye spaced from the movable clamping plate, the yam guide arm and movable clamping plate being integrally Conned from a resilient sheet material.

Preferably the resilient sheet material is spring steel and the movable to plate and guide arm are preferably formed by stamping.

Preferably the clamping plate is mounted on a support shaft such that the guide arm extends substantially perpendicularly therefrom, the arm being arranged to be resiliently deflectable about a fulcrum extending 5 substantially perpendicularly to the axis of said shaft.

Preferably the clamping plate includes a cranked portion through which said support shaft passes, the cranked portion together with the static plate defining a passageway through which yarn may freely pass.

Preferably the biasing means comprises a compression spring located between the cranked portion and a rotatable nut formed on a screw threaded portion of the support shaft.

s Preferably the screw threaded portion includes visual indication means for indicating the axial position of the nut on the shaft.

According to another aspect of the invention there is provided a creel having a plurality of yarn package support spindles and an individual yarn lo tensioner as defined above associated with each respective spindle.

Preferably the spindles are arranged in rows and the tensioners are mounted on cross bars arranged in rows intermediate the rows of spindles, the rows of cross-bars defining yarn guides for guiding yarn out of the creel.

Various aspects of the present invention are hereinafter described with reference to t he accompanying drawings, in which: Figure 1 is an end view of part of a creel including yarn tensioner no according to a preferred embodiment of the present invention; Figure 2 is a side view of the creel as shown in Figure 1; and Figure 3 is a plan view of the creel as shown in Figure 1.

Referring initially to Figure 1 there is shown part of a creel lO Is including a plurality of rows of yarn packages 15. In Figure 1, two rows Rat, R2 of yarn packages 15 are shown by way of example. Typically there would be considerably more than 2 row of yam packages 15 in the creel 10.

Also by way of example, two yarn packages 15a, 15b are shown in so each row Rat, R2. Again, typically there would be considerably more than

two yarn packages 15 in each row. For example, for a Wilton loom weaving with 8 colours, there would be about 8000 packages mounted in the creel 10.

5 Each yarn package 15 is rotatably mounted on a support spindle 16 mounted on the frame (not shown) of the creel 10.

Located adjacent to each support spindle 16 is a yarn tensioner 20 according to a preferred embodiment of the invention.

Each yarn tensioner 20 preferably includes yarn clamp 19 comprising a static yarn clamping plate 21 and a movable yarn clamping plate 22. The movable clamping pate 22 is movably mounted on a support shaft 23 which projects from the static plate 21.

Preferably the static clamping plate 22 is provided with a cranked portion 22a which includes an aperture (not shown) through which shaft 23 passes and which is spaced from the static plate 21 to define a passageway 26 to permit yarn Y to pass freely around the shaft 23.

The clamping plate 22 further includes a reaction arson 22b located on the opposite side of shaft 23 which abuts against an extension of the static plate 21. The reaction arson 22b and extension of the static plate 21 preferably include anti-rotation co-operating means, preferably in the form of a tongue 29a and groove 29b which serve to prevent rotation of the movable plate 22 about shaft 23.

Resilient biasing means, preferably in the form of a compression spring 26, are provided for resiliently biasing the movable plate 22 into so clamping abutment with the static plate 21.

Preferably the spring 26 is mounted on the shaft 23 inbetween the cranked portion 22a of movable plate 22 and a rotary nut 30 which is screw threadably received upon a screw threaded portion 23a of shaft 23.

5 Rotation of the nut 30 causes it to be moved toward/away from the movable plate 22 thereby increasing/decreasing the compressed state of spring 26 and so increasing/decreasing the resilient biasing force applied onto movable plate 23 for clamping engagement with static plate 21.

lo Preferably the outer periphery of nut 30 is circular and is provided with a toothed formation 31 to thereby define a toothed gear. This enables an operative to use a toothed rack to engage the tooth formation 31 for affecting rotation of the nut 30. In this way an operative can quickly and easily adjust the biasing force applied to movable plate 22.

Preferably the threaded portion 23a is provided with visual indicator means, preferably in the form of a series of axially spaced annular groves 33, which enable an operative to visually determine the axial position of the nut 30 along the threaded portion 23a. This enables the operative to apply a so consistent biasing force on each yarn tensioner 20.

Preferably on the side of the movable plate 22 opposite the cranked portion 22a, the movable plate 22 includes a yarn guide arm 40 which extends from the movable plate 22 in a direction which is substantially :5 perpendicular to the axis of shaft 23.

The yarn guide arm 40 is formed from a resilient sheet material, such as spring steel so as to be resiliently bendable about a fulcrum extending substantially perpendicularly to the axis of shaft 23 between a rest position

(as shown by arm 40' in Figure 3) and a deflected position (as shown by arm 40" in Figure 3).

The yarn guide arm 40, adjacent to its terminal end carries a yarn 5 guide eye 42.

In use yarn Y is fed from a yarn package 15 through passageway 26, around shaft 23 inbetween clamping plates 21, 22, along guide arm 40, through eye 42 and to the loom (not shown). When yarn Y is drawn by the lo loom, the ann 40 is caused to resiliently deflect and thereby apply tension to the yarn. Where the loom stops drawing yarn Y and/or slightly releases it, the arm 40 moves from its deflected position back towards its rest position and in so doing maintains the yarn BY downstream of the eye under a residual tension. This is particularly advantageous in a creel having a large number of yarns Y passing therethrough as it prevents the yarns Y slackening off and possibly becoming tangled with one another and/or parts of the creel.

Whilst yarn Y is being drawn off by the loom, movement of the arm to 40 to its deflected position causes the arm 40 to act upon the movable plate 22 in order to reduce the clamping biasing force applied by the spring 26.

The amount of reduction in the clamping force is proportional to the amount by which the arm 40 is deflected which in turn is proportional to the rate at which the loom draws yarn Y. Thus the yarn tensioner 10 acts to automatically vary the clamping force between plates 21, 22 in order to maintain, (in combination with the tension applied by resilient deflection of arm 40), a desired amount of tension in the yarn Y. The tension values in the yarn upstream of the tensioner 20 tend to so vary as the yarn is pulled off the yarn package 15. This is due to the yarn

translating back and forth along the package and due to the yarn sticking to the package as it is drawn off.

The combined effect of the clamp 19 and arm 40 is that it applies a 5 tension to the yarn downstream of the tensioner 20 which has a lower variation in yarn tensions than the tensions in the yarn located upstream of the tensioner 20.

Preferably the clamping plate 22 and yarn guide arm 40 are integrally lo formed as a metal pressing from a suitable spring steel plate. Such an integral clamping plate 22 and yarn guide arm 40 may be accurately mass produced. Preferably each static plate 21 is mounted on a cross-bar 50 located is adjacent to and parallel with a row of spindles 16. A plurality of cross-bars 50 are thereby arranged in a row located inbetween adjacent rows of spindles 16.

Yarn is preferably fed to a given yarn tensioner 20 from a yang to package 15 carried by a spindle 16 which is the immediate neighbour to the spindle 16 closest to the guide 20.

This has the advantage of the guide 20 being spaced from the yarn package 15 (carrying the yarn being fed through the guide) by at least one 25 spacing between spindles 16 and so reduces the angle through which the yarn Y has to travel when translating along the package 15 during yarn pull-

off and thereby reduces yarn tension variation.

Yarn on the downstream side of the tensioners 20 in the same row of so cross-bars 50 is trained over the row of cross-bars 50 in their passage out of

the creel to the loom. Accordingly, each row of cross-bar 50 serves to act as a guide for transport of yarn out of the creel in a disciplined manner

Claims

À À À- À 1 i CLAIMS

1. A yarn tensioner including a static yarn clamping plate co-operating with a movable yarn clamping plate, biasing means for biasing the movable clamping plate into clamping abutment with the static clamping plate' a yarn guide arm extending from the movable clamping plate, the guide arm having a yarn eye spaced from the movable clamping plate' the yarn guide arm and movable clamping plate being integrally formed from a resilient sheet material.

2. A yarn tensioner according to Claim 1 wherein said resilient sheet

material is spring steel.

3. A yarn tensioner according to Claim 1 or 2 wherein said movable plate and guide arm are formed by stamping.

4. A yarn tensioner according to Claim 1, 2 or 3 wherein said movable clamping plate is mounted on a support shaft such that the guide arm extends substantially perpendicularly therefrom, the arm being arranged to be resiliently deflectable about a fulcrum extending substantially perpendicularly to the axis of said shaft.

5. A yarn tensioner according to Claim 4 wherein said movable clamping plate includes a cranked portion through which said support shaft passes, the cranked portion together with the static plate defining a passageway through which yarn may freely pass.

6. A yarn tensioner according to Claim 5 wherein the biasing means comprises a compression spring located between the cranked portion and a rotatable nut formed on a screw threaded portion of the support shaft.

t1.:. i-

7. A yarn tensioner according to Claim 6 wherein the screw threaded portion includes visual indication means for indicating the axial position of the nut on the shaft.

8. A yarn tensioner substantially as herein described with reference to and as illustrated in the accompanying drawings.

9. A creel having a plurality of yarn package support spindles and an individual yarn tensioner according to any preceding claim associated with each respective spindle.

10. A creel according to Claim 9 wherein the spindles are arranged in rows and the tensioners are mounted on cross bars arranged in rows intermediate the rows of spindles, the rows of cross-bars defining yarn guides for guiding yarn out of the creel.