GB2378189A

GB2378189A - Yarn tensioning apparatus

Info

Publication number: GB2378189A
Application number: GB0118867A
Authority: GB
Inventors: David Waite
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2001-08-02
Filing date: 2001-08-02
Publication date: 2003-02-05
Anticipated expiration: 2021-08-02
Also published as: BE1016040A3; GB2402680B; GB0118867D0; GB2378189B; DE10235200A1; GB0419136D0; GB2402680A

Abstract

A yarn tensioning apparatus, e.g. for a loom, comprises upstream and downstream tensioners 24,51 the tensioner 51 being in the form of a yarn trap 53 with upstream and downstream yarn guides 52,55. The guide 55 resiliently biasses the yarn to a trapped position in the trap 53 but is deflectable on yarn being consumed by the loom or other device CD to release the yarn from the trapped position. The upstream guide 52 is displaceable to adjust the position at which the guide 55 releases the yarn form the trap 53 and thereby to adjust the effective tension.

Description

The present invention relates to a yam feed apparatus.

According to one aspect of the present invention there is provided a yam feed apparatus for supplying yam to a consuming device, the apparatus including first and second yam tensioners defining a path of travel for yam to which tension is to be applied, the first yam tensioner being located upstream of the second yam tensioner relative to said path of travel, the second yam tensioner including a yam trap and first and second yam guides located either side of said trap, the first and second yam guides defining a path of travel of the yam through the trap, said second guide being located on the downstream side of the trap and being resiliently biased to a rest position whereat it defines a first path of travel for said yam through the trap which causes yam to be trapped by said trap, the second guide being resiliently deflected, when yam is drawn by the consuming device, to a deflected release position whereat the first and second guides co-operate to define a second path of travel for said yam whereby yam is not trapped by said trap, said first guide being selectively movable to a position within a range of positions in order to selectively change the direction of said second path and thereby vary the release position of the second guide.

Preferably upstream of the first yam tensioner there is provided a yam drawing device which is operable to draw a predetermined length of yam from a yam store in readiness for said length of yam to be drawn through said first and second tensioners.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which :-

1

Figure 1 is a schematic plan view of a yam feed apparatus according to an embodiment of the present invention; Figure 2 is a side view of the apparatus shown in Figure 1; Figure 3 is an end view of the apparatus shown in Figure 1; and Figures 4a, 4b are part plan views similar to Figure 1 showing the apparatus in different tension modes.

Referring initially to Figures 1 to 3, a yam feed apparatus according to an embodiment of the present invention is generally shown at 10. The apparatus includes a first yam tensioner 22 and a second yam tensioner 50 through which yam Y is intermittently drawn by a consuming device CD (such as a loom).

Typically, as shown in Figure 1, a plurality of apparatuses 10 according to the present invention are located side by side in a row so that each apparatus draws yam from an associated individual yam store, there being a plurality of side by side yam stores Ys.

For simplicity, only one apparatus 10 is illustrated in full in the drawings.

The apparatus further includes a yam drawing means 20 located upstream of the first tensioner 22 which functions to draw a predetermined length of yam Y from the yam store Ys. The yam store Ys may be of any suitable type, for example a yam package or a yam store as disclosed in our European Patent 0 422 093.

Preferably the yam drawing means 20 includes a static guide preferably in the form of a rod 23, and a yam drawing member, preferably in the form of a rod 27 which is movably mounted inbetween the static guide 21 and the yam tensioner 22. Preferably the yam tensioner 22 is in the

form of a roller 24 and co-operating plate 25. The yarn tensioner 22 acts to apply tension to the yam Y by virtue of gravity bias of the roller 24 onto the plate 25.

The rod 27 is reciprocally movable from a rest position (shown in solid lines in Figure 2) to a displaced position (shown in broken lines in Figure 2).

At its rest position, the rod 27 is located adjacent to a linear path of travel of the yam Y as determined by the rod 23 and tensioner 22.

When the rod 27 is moved to its displaced position, the tensioners 22 and 50 act as a yam brake and so a yam loop L is drawn from the yam store only.

The distance D between the rest and displaced positions of the rod 27 is chosen to produce a desired length of yam in the yam loop L. The mechanism for reciprocally displacing rod 27 may be adapted so as to enable the distance D of displacement to be varied as desired. After drawing loop L, the rod 27 is returned to its rest position leaving the loop L in a free condition. It will be appreciated, therefore, that the loop L is free of tension and is held in readiness to be drawn through the tensioner 22.

Downstream of tensioner 22 there is provided the second yam tensioner 50 which is selectively adjustable for adjusting the tension applied to yam Y.

The adjustable yam tensioner 50 includes a yam trap 51 and a first i movable yam guide 52 located inbetween yam trap 51 and the yam tensioner 22.

Located downstream of the yam trap 51, the adjustable tensioner 50 further includes a second movable yam guide 55. Yam Y is guided by both guides 52 and 55 along a path of travel through the trap 51.

The trap 51 is preferably in the form of a resilient strip 53 of material which is anchored at one end to a planar support 60. The strip 53 is inclined relative to the support 60 to define therebetween an open mouthed wedge shaped passage 61. When yam is guided into the bottom of the passage 61 it is wedgedly trapped between the strip 53 and support 60.

The second guide 55 is preferably in the form of a yam guide eye 56 mounted on the end of a spring 57.

The second guide eye 56 is resiliently biased to a rest position (as shown in solid lines in Figures 1,4A, 4B). In its rest position, the second guide eye 56 is located to define a first outward path of travel P of yam from the trap 51 which ensures that the yam is guided into the bottom of the passage 61. Accordingly, when the guide eye 56 is in its rest position, yam is trapped by trap 51.

During use, yam Y is drawn by a consuming device such as a loom located downstream of guide 55. When this occurs, guide eye 56 is resiliently deflected from its rest position to a deflected position (as shown in broken lines in Figures 1,4A and 4B).

As the guide 55 is deflected, it alters the angle of the outward path of travel PD relative to the trap 51. Eventually continued deflection of the guide 55 will result in the path of travel of the yam through the trap 51 being determined by a direct line of path PD between guides 52 and 55 when

this occurs, the direct linear path PD is chosen to guide the yam through the trap 51 at a spaced location from the bottom of passage 61. Accordingly in this condition, the yam Y passes through trap 51 without being trapped.

In this condition, whilst yam is being drawn by the consuming device, the tension applied to the yam being supplied to the consuming device is a combination of the tension applied by tensioner 22 and by guide 55.

The amount of tension applied by tensioner 22 is constant but that applied by the guide 55 will vary dependent upon the rate of yam being drawn by the consuming device during a yam consuming cycle, e. g. a weft insertion in a loom or a pile forming cycle in a carpet loom. Thus, at the beginning of the consuming cycle, as yam is drawn by the consuming device, the guide 55 is initially moved from its rest position to a yam release position whereat the direct path PD is initially attained. At the release position, the guide 55 applies a predetermined amount of tension onto the yam being drawn. If the rate of consumption increases, the guide 55 will be further deflected beyond its release position and thereby apply a higher tension.

The level of the tension applied by the guide 55 when reaching its release position may be adjusted by moving the position of yam guide 52 in order to change the angle 0 of the inward path of travel Pi of the yarn relative to the trap 51.

As illustrated in Figures 4A, 4B, the guide 52 is preferably in the form of a pin 52a mounted on an elongate support bar 52b which is slidably mounted for longitudinal movement. By moving the guide 52 to the left, the angle 0 is increased. Accordingly, the distance that guide 55 has to be

deflected in order to attain its release position is reduced. Since the inherent bias for returning the guide eye 56 to its rest position progressively increases as a function of its deflection from its rest position, the amount of tension applied by the guide at its release position is thereby reduced.

Similarly, if the guide 52 is moved to the right, angle 0 is reduced and so the guide eye 56 has to move a greater distance before reaching its release position. Accordingly, the amount of tension applied is thereby increased.

A range R of positions to which the guide 52 may be selectively moved is schematically shown in Figures 4A, 4B. Moving the guide 52 to any position in this range enables the guide 55 at its rest position to guide yam to be trapped in tap 51 and enables the guide 55 to be moved to a release position whereat guides 52 and 55 co-operate to guide yam through the trap 51 without being tapped.

After the consuming device has stopped consuming yam, it will release a small amount of yam. This permits the guide eye 56 to return to its rest position and trap yam in trap 51 in readiness for the yam feed cycle to be repeated. As the guide 55 returns to its rest position, it takes up slack in the yam between itself and the consuming device and also imparts a residual low tension therein.

Claims

1. A yam feed apparatus for supplying yam to a consuming device, the apparatus including first and second yam tensioners defining a path of travel for yam to which tension is to be applied, the first yam tensioner being located upstream of the second yam tensioner relative to said path or travel, the second yam tensioner including a yam trap and first and second yam guides located either side of said trap, the first and second yam guides defining a path of travel of the yam through the trap, said second guide being located on the downstream side of the trap and being resiliently biassed to a rest position whereat it defines a first path of travel for said yam through the trap which causes yam to be trapped by said trap, the second guide being resiliently deflected, when yam is drawn by the consuming device, to a deflected release position whereat the first and second guides co-operate to define a second path of travel for said yam whereby yam is not trapped by said trap, said first guide being selectively movable to a position within a range of positions in order to selectively change the direction of said second path and thereby vary the release position of the second guide.

2. Apparatus according to Claim 1 wherein the trap is in the form of a resilient strip of material anchored at one end to a planar support, the strip being inclined relative to the support to define therebetween an open mouthed wedge shaped passage, within which said yam is trapped when extending along said first path of travel.

3. Apparatus according to Claim 1 or 2 wherein said second guide is in the form of a yam guide eye mounted on the end of a spring.

4. Apparatus according to claim 1,2 or 3 wherein said first guide is arranged to guide the yam at an angle 8 relative to the trap, the first guide

being movable to increase or decrease the angle 8 in order to change the direction of said second path.

5. Apparatus according to Claim 4 wherein said first guide is defined by a pin mounted on a slidable bar.

6. A yam feed apparatus substantially as herein described with reference to and as illustrated in the accompanying drawings.