GB2051895A

GB2051895A - Shuttle for Circular Looms Comprising Means for Indicating a Thread Breakage

Info

Publication number: GB2051895A
Application number: GB8018019A
Authority: GB
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 1979-06-29
Filing date: 1980-06-02
Publication date: 1981-01-21
Also published as: BR8004044A; GB2051895B; ATA219780A; JPS569444A; DE2926388A1; AT366112B; JPS6367573B2; DE2926388C2; FR2460353B1; FR2460353A1

Abstract

In a shuttle 1 for a circular loom, the hub 6 of a rotary weft bobbin- supporting disc 3 carries a ring 13 which is mounted to be rotatable and axially displaceable. A reflector strip 23 extends over part of the ring circumference. A compression spring 16 biasses the ring 13 into frictional engagement with the disc 3. When the bobbin and disc 3 are rotating, the frictional force turns the ring 13 to a limiting position where the reflector strip 23 is beyond the influence of a photoscanner. If the ring 13 stops turning on the occurrence of a thread breakage, the friction between the ring and disc drops to a level where a spring 21 can return the ring 13 to a limiting position where the reflector strip 23 is detected by the photoscanner. <IMAGE>

Description

SPECIFICATION Shuttle for Circular Looms Comprising Means for Indicating a Thread Breakage The-invention relates to a shufflefor circular looms, comprising a curved skid which forms the shuttle body and on the side of which opposite the runner face there are brackets with rotary seats for the weft bobbin that consist of a rotary cone whichcan be retracted against a spring force and engages in the bobbin core and a disc which has a central cone, means for braking on thread breakage,-and a reflecting layer turned by the disc and detected by a reflection photoscanner when the disc- is stationary.

In know shuttles of this kind,-a reflector strip stuck to the sleeve-like hub extension of the disc encloses the hub in the manner of a sleeve. A disc is placed at the end of the hub. Between the two discs enclosing the reflector strip between each other, blades are eccentrically mounted about pins arranged parallel to the bobbin axis. On rotation of the discs, the centrifugal forces acting on the blades cause them to-swing out of their substantially radial position into a position substantially tangential to the enveloping cylinder described by the bearing pins, where they completely cover the reflector strip.If the discs are braked to -a standstill, the blades fall back into their substantially radial position in which the reflector strips detected by a reflection photoscanner which is-mounted on the frame of the loom and which notifies the standstill of the weft bobbin and hence the thread breakage. The known shuttle could without detection continue to run with a stationary weft bobbin, i.e. with a torn weft thread, if the blades are blocked in their swung out position where they cover the reflecting strip. Such blockage of the blades may result from the soiling of the pivots or jamming so that the return forces which are set up only by the low weight of the blades when the weft bobbin is at a standstill are insufficient to pivot the blades to their substantially tangential position.

It is therefore the problem of the invention to provide a shuttle in which standstill of the weft bobbin as a result of thread breakage is detected and notified more reliably.

According to the invention, this problem is solved in a shuttle of the aforementioned kind in that the reflecting layer covers part of the circumference of a ring which is rotatably and axially displaceably mounted on the hub of the disc and which is pressed against the disc by a spring in such a way that its end face adjacent the disc is supported on the side face of the disc, and that a tension spring secured between the ring and shuttle body has its force so adapted to the frictional force between the ring and disc that, with the ring turned through an angle where the reflecting layer is beyond the zone of the beam of the reflection photoscanner when the weft bobbin is rotating, the spring turns the ring so far back when the bobbin is stationary that the reflecting layer is within the zone of the beam of the reflection photoscanner.If the disc, which usually also forms the brake disc that is braked by a brake shoe upon a thread breakage, is turning, the frictional force transmitted by the disc on the ring causes the-latter to be turned through an angle of a size such that its circumferential region that is covered by the reflecting layer is moved out of the beam of the reflection photoscanner whereas it is in the beam when the disc is stationary. However, if a thread breakage now occurs and the weft bobbin is consequently braked, the frictional force in the shuttle according to the invention acting between the disc and the ring on the hub of the disc is reduced in such a way that the tension spring can turn the ring back so far that the reflecting layer enters the path of the beam of the reflection photoscanner.The control means according to the invention are substantially insensitive to exterior influences and therefore reliably notify a thread breakage.

Desirably, to set the pressure of the ring on the disc, a compression spring is clamped between the ring and a corrugated nut screw-fitted on the end of the hub. The corrugated nut is provided with conventional anti-rotation means so that it can be fixed on the hub after the correct pressure has been set.

The limiting positions of the ring are preferably defined by abutments on the shuttle body.

According to a further advantageous embodiment of the invention, the disc is provided with a brake lining where the end of the ring rubs on it.

One example of the invention will now be described in more detail with reference to the drawing, wherein:- Fig. 1 is a longitudinal section through the mounting of the disc which mounts and brakes the weft bobbin at one side, and Fig. 2 is a section through the Fig. 1 mounting taken on the line Il-Il.

The weaving shuttle partly illustrated in the Figures consists in known manner of a basic body 1 which carries a yoke with a thread guide eye and a rear guide roller (which are not shown). In the front portion of the basic body 1 there is a clamping.cone (not shown) which is axially displaceable against the force of a spring, is rotatably mounted and serves to clamp the weft bobbin. The other side of the weft bobbin is held by an axially immobile cone 2 against which the winding core of the weft bobbin is pressed by the spring influenced cone and which is made in one piece with the brake disc 3. At the side remote from the cone 2, the brake disc 3 comprises a brake lining 4 which is operatively connected to a brake shoe (not shown) which drops into position upon a thread breakage. To this extent, the shuttle corresponds to the shuttle described by way of example in DE-OS 28 46 920.

The disc 3 provided with the brake lining 4 is mounted on the bracket 5 of the basic body 1.

The disc 3 is provided with a sleeve-like hub 6 which forms an extension at the back of the disc.

Ball bearings 7, 8 are pushed into the bore of the hub 6. Of these, the outer race of the ball bearing 8 is fixed to the inside of the hub 6 by circlips 9, 10. The inner races of the ball bearings 7, 8 are spaced apart by a spacing sleeve 11 and mounted on the bearing pin 12 which is screw-connected to the bracket 5.

The ring 13 is rotatably and axially displaceably mounted on the outside of the hub 6 by way of the ball bearing 14. The outer race of the ball bearing 14 is fixed in the bore of the ring 14 by circlips. The inner race of the ball bearing 14 is displaceable on the hub 6. The ring 13 is provided with a flat end face 1 5 with which it rests against the brake lining 4 of the disc 3. A compression spring 16 placed over the hub 6 is stressed between the inner race of the ball bearing 14 and the corrugaged nut 1 7. For securityagainst rotation, the corrugated nut 17 is provided with a securing plate 18.

The ring 13 is provided with a circumferential groove 1 9 in which one end of a tension spring 21 is secured to a pin 20 passing through the groove. The other end of the tension spring 21 is secured to the pin 22 connected to the bracket 5.

A section of a reflecting strip 23 is stuck to the ring 13. Provision is also made for a further pin 24 which passes transversely through the circumferential goove 19 of the ring 13 and which, in the same way as the pin 20, cooperates with the pin 25 which is connected to the basic body 1, projects into the groove 19 and forms an abutment. In the Fig. 2 position, the ring 13 is in its limiting position turned by the disc 3 provided with the brake lining 4, the pin 20 bearing against the abutment 25 and the reflecting layer 23 being turned out of the path of the beam S of the reflection photoscanner. If the disc 3 comes to a standstill, the spring 21 will pull the ring 1 3 back so far that the pin 24 abuts the abutment 25. In this limiting position, the reflecting layer 23 is disposed within the path of the beam S of the reflection photoscanner so that the latter will indicate a thread breakage.

Claims

1. A shuttle for a circular loom, comprising a curved skid which forms the shuttle body and on the side of which opposite the runner face there are brackets with rotary seats for the weft bobbin that consist of a rotary cone which can be retracted against a spring force and engages in the bobbin core and a disc which has a central cone, means for braking the disc on a thread breakage, and a reflecting layer turned by the disc and detected by a reflection photoscanner when the disc is stationary, characterised in that the reflecting layer (23) covers only part of the circumference of a ring (13) which is rotatably and axially displaceably mounted on the hub (6) of the disc (3) and which is pressed against the disc (3) by a spring (16) in such a way that its end face (15) adjacent the disc (3)-is supported on the side face (4) of the disc, and that a tension spring (21) secured between the ring (13) and shuttle body (1) has its force so adapted to the frictional force between the ring (13) and disc (3) that, with the ring (13) turned through an angle where the reflecting layer (23) is beyond the zone of the beam (S) of the reflection photoscanner when the' weft bobbin is rotating, the spring turns the ring so far back when the bobbin is stationary that the reflecting layer (23) is within the zone of the beam (S) of the reflection scanner.

2. A shuttle according to claim 1, characterised in that, to set the pressure of the ring (13) on the disc (3), a compression spring (16) is clamped between the ring (13) and a corrugated nut (17) screwfitted on the end of the hub (6).

3. A shuttle according to claim 1 or claim 2, characterised in that the limiting positions of the ring (3) are defined by abutments (20, 24, 25) on the ring (13) and the shuttle body (1).

4. A shuttle according to one of claims 1 to 3, characterised in that the disc (3) is provided with a brake lining (4) where the end (1 5) of the ring (13) rubs on it.

5. A shuttle for a circular loom constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.