GB2057023A - Apparatus for gripping running waft threads on travelling-wave looms - Google Patents

Abstract

An apparatus for gripping running weft threads comprises a disc 2 having thread guides 16 and fitted with a peripheral tyre and a gripping device consisting of a slotted arcuate support 8, a pair of pulleys 9, 10 adjustable on the support, and a belt 11 trained around the pulleys and cooperating with the tyre 6 for braking the threads therebetween, the coefficient of friction of the tyre material being greater than that of the belt material. The position of the pulleys 9, 10 is adjustable to vary the length of the belt 11 engaged with the tyre 6. <IMAGE>

Description

SPECIFICATION Apparatus for gripping running weft threads on travelling-wave looms The present invention relates to apparatus for gripping a running weft thread in a travelling wave loom.

According to the invention there is provided an apparatus for gripping a weft thread on a travelling-wave loom, comprising a rotatable disk having a peripheral tyre, and means cooperable with the tyre for braking a weft thread therebetween, the material of the tyre having a coefficient of friction with the thread which is greater than that of said cooperating means with the thread.

Where the disk has guides for guiding a plurality of threads, the gripping means cooperating with the tyre can be common to all the moving threads, which can simplify the design of the loom and make servicing easier. Moreover, by employment of a single common means, intricate parts become redundant, whereby the sluggishness of the system as a whole is minimized.

The cooperating means preferably includes a pair of pulley movably mounted on an arcuate support and a belt extending around the pulleys and cooperating with the tyre between the pulleys. The pulleys can be adjusted in position to vary the time and duration of thread braking.

Given below by way of example is a detailed description of the present invention with reference being made to the accompanying drawings, wherein: Fig. 1 is a front view of an apparatus for gripping a running thread, according to the invention; Fig. 2 is a section view taken along line Il-Il of Fig. 1; Fig. 3 same as in Fig. 1, top view; Fig. 4 same as in Fig. 1, side view.

The proposed apparatus for gripping a running weft thread comprises, on a rotatable shaft 1 (Fig.

1), a disk 2 with an element 3 for braking weft threads 4 (Fig. 2) arranged on the periphery thereof. The element 3 represents a tyre 6 placed I in an annular slot 5 and a gripping block 7 partially embracing this tyre, the tyre 6 being fabricated from a material with a coefficient of friction against the thread exceeding that of the material of the block 7. The angle a of lap of the gripping block 7 and the tyre 6 is adjustable, whereby the duration of the thread gripping may be changed.

Included in the block 7 and mounted on a stationary base 8 are a pair of pulleys 9 and 10 and a gripping belt 11 enveloping these pulleys, the ends thereof being joined through a spring 12.

The pulleys 9 and 10 are mounted on the base 8 so that the distance therebetween can be changed in order to adjust the angle a.

The required changes in the distance between the pulleys 9 and 10 are possible owing to their being arranged in an arcuate slot 1 3 made in the base 8.

The shaft 1 also mounts package-holders 14 (Fig. 3) with bobbins 15 for the weft thread 4. For guiding the thread 4, there are provided threadguides 1 6 installed on ribs 1 7 of the disk 2.

The thread 4 from the bobbin is placed in the thread-guides 14, then in winding heads 1 8 installed on a rotatable body 19.

At the exit side of the apparatus, next to the selvage of a cloth 20 (Fig. 4), there are placed cutters 21 and a grip 22 for the thread being wound onto a spool 23 of a carrier 24 of the weft thread.

The apparatus operates as follows.

Placed on the spool 23 of each of the carriers 24 is the weft thread 4 freely unwound from the bobbin 15.

After being threaded, the carriers 24 emerge from under the winding heads 18.

As soon as the weft thread is worked up into the cloth, the cutters 21 sever the thread 4. At the same time, the threadguides 1 6 place the weft thread between the belt 11 of the gripping block and the tyre 6. Now, because of the thread 4 being unable to move in the direction of unwinding and because of the body 19 with the winding heads 18 being turned, the length of the severed end of the weft thread 4 is caused to diminish. The angle a of gripping of the weft thread 4 can be changed by shifting the pulley 10 relative to the pulley 9 along the arcuate slot 13.

Used as the tyre material may be a rubberized cloth with a coefficient of friction against the thread f > 1, while a polished metal band with a coefficient of friction against the thread f =0.1-0.2 may be employed as the gripping block.

1. An apparatus for gripping a weft thread on a travelling-wave loom, comprising a rotatable disk having a peripheral tyre, and means cooperable with the tyre for braking a weft thread therebetween, the material of the tyre having a coefficient of friction with the thread which is greater than that of said cooperating means with the thread.

2. An apparatus according to claim 1, wherein said means cooperates with the tyre over a circumferential portion thereof of adjustable length.

3. An apparatus according to claim 2, wherein said means comprises a support, a pair of pulleys mounted on the support, and a belt extending around the pulleys and cooperating with the tyre between the pulleys, at least one pulley being adjustable on the support to vary the length of the belt cooperating with the tyre.

4. An apparatus according to claim 3, wherein the pulleys are mounted on the support for

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Apparatus for gripping running weft threads on travelling-wave looms The present invention relates to apparatus for gripping a running weft thread in a travelling wave loom. According to the invention there is provided an apparatus for gripping a weft thread on a travelling-wave loom, comprising a rotatable disk having a peripheral tyre, and means cooperable with the tyre for braking a weft thread therebetween, the material of the tyre having a coefficient of friction with the thread which is greater than that of said cooperating means with the thread. Where the disk has guides for guiding a plurality of threads, the gripping means cooperating with the tyre can be common to all the moving threads, which can simplify the design of the loom and make servicing easier. Moreover, by employment of a single common means, intricate parts become redundant, whereby the sluggishness of the system as a whole is minimized. The cooperating means preferably includes a pair of pulley movably mounted on an arcuate support and a belt extending around the pulleys and cooperating with the tyre between the pulleys. The pulleys can be adjusted in position to vary the time and duration of thread braking. Given below by way of example is a detailed description of the present invention with reference being made to the accompanying drawings, wherein: Fig. 1 is a front view of an apparatus for gripping a running thread, according to the invention; Fig. 2 is a section view taken along line Il-Il of Fig. 1; Fig. 3 same as in Fig. 1, top view; Fig. 4 same as in Fig. 1, side view. The proposed apparatus for gripping a running weft thread comprises, on a rotatable shaft 1 (Fig. 1), a disk 2 with an element 3 for braking weft threads 4 (Fig. 2) arranged on the periphery thereof. The element 3 represents a tyre 6 placed I in an annular slot 5 and a gripping block 7 partially embracing this tyre, the tyre 6 being fabricated from a material with a coefficient of friction against the thread exceeding that of the material of the block 7. The angle a of lap of the gripping block 7 and the tyre 6 is adjustable, whereby the duration of the thread gripping may be changed. Included in the block 7 and mounted on a stationary base 8 are a pair of pulleys 9 and 10 and a gripping belt 11 enveloping these pulleys, the ends thereof being joined through a spring 12. The pulleys 9 and 10 are mounted on the base 8 so that the distance therebetween can be changed in order to adjust the angle a. The required changes in the distance between the pulleys 9 and 10 are possible owing to their being arranged in an arcuate slot 1 3 made in the base 8. The shaft 1 also mounts package-holders 14 (Fig. 3) with bobbins 15 for the weft thread 4. For guiding the thread 4, there are provided threadguides 1 6 installed on ribs 1 7 of the disk 2. The thread 4 from the bobbin is placed in the thread-guides 14, then in winding heads 1 8 installed on a rotatable body 19. At the exit side of the apparatus, next to the selvage of a cloth 20 (Fig. 4), there are placed cutters 21 and a grip 22 for the thread being wound onto a spool 23 of a carrier 24 of the weft thread. The apparatus operates as follows. Placed on the spool 23 of each of the carriers 24 is the weft thread 4 freely unwound from the bobbin 15. After being threaded, the carriers 24 emerge from under the winding heads 18. As soon as the weft thread is worked up into the cloth, the cutters 21 sever the thread 4. At the same time, the threadguides 1 6 place the weft thread between the belt 11 of the gripping block and the tyre 6. Now, because of the thread 4 being unable to move in the direction of unwinding and because of the body 19 with the winding heads 18 being turned, the length of the severed end of the weft thread 4 is caused to diminish. The angle a of gripping of the weft thread 4 can be changed by shifting the pulley 10 relative to the pulley 9 along the arcuate slot 13. Used as the tyre material may be a rubberized cloth with a coefficient of friction against the thread f > 1, while a polished metal band with a coefficient of friction against the thread f =0.1-0.2 may be employed as the gripping block. CLAIMS

1. An apparatus for gripping a weft thread on a travelling-wave loom, comprising a rotatable disk having a peripheral tyre, and means cooperable with the tyre for braking a weft thread therebetween, the material of the tyre having a coefficient of friction with the thread which is greater than that of said cooperating means with the thread.

2. An apparatus according to claim 1, wherein said means cooperates with the tyre over a circumferential portion thereof of adjustable length.

3. An apparatus according to claim 2, wherein said means comprises a support, a pair of pulleys mounted on the support, and a belt extending around the pulleys and cooperating with the tyre between the pulleys, at least one pulley being adjustable on the support to vary the length of the belt cooperating with the tyre.

4. An apparatus according to claim 3, wherein the pulleys are mounted on the support for movement along an arcuate path centred on the disk axis.

5. An apparatus for gripping a running weft thread in a travelling-wave loom, substantially as herein described with reference to the accompanying drawings.