GB2078791A

GB2078791A - Thread clamp device for a slide knitting machine

Info

Publication number: GB2078791A
Application number: GB8113382A
Authority: GB
Original assignee: Kombinat Textima VEB
Current assignee: Kombinat Textima VEB
Priority date: 1980-06-23
Filing date: 1981-04-30
Publication date: 1982-01-13
Also published as: CS245712B1; GB2078791B; CS311081A1; DE3112534A1; DD154265A3; CH650815A5

Abstract

A thread clamping device for a knitting machine serves to clamp a thread between a thread guide and a reel body of the machine after the thread has been separated from a knitted fabric. The device comprises an open base member (1) having a slide surface (2) for a thread (3) to slide therealong. An open spring (4, 5) is arranged at each of a thread inlet end and a thread outlet end of the surface to press the thread onto the surface (2). A tongue (6), bearing in a mounting (7) at an upper side (8) of the member (1), is pressed by a tension spring (9) towards the surface (2). <IMAGE>

Description

SPECIFICATION Thread clamping device for a knitting machine The present invention relates to a thread clamping device for a knitting machine, such device serving for, in particular, clamping of a thread between a thread guide known and a reel body of the machine after the thread has been separated from a knitted fabric.

On straight and circular knitting machines with a knitting system revolving in one direction, a thread clamp is associated with each thread guide at the end of the needle boards for clamping the threads after they have been separated from the knitted fabric. This thread clamp, consisting of two clamp arms, a splaying wedge and a controi component, is actuated by a cam disposed on the needle boards.

The clamp suffers, however, from the disadvantage that it includes numerous components that are subject to wear, must be actuated by special cams disposed on the needle board, and requires a great deal of time in order to be accurately set up. In addition, a specific actuating time is required, which imposes limits on knitting speed and the distance between the individual knitting systems.

A thread guide and clamping device with multiple thread change is disclosed in DE-OS 2 410 415, wherein clamp pins are disposed on a thread guide disc provided with passages corresponding to the number of thread changes, which pins press the threads under spring-loading against the wall of the bore of the clamp positions.

This device also has the disadvantage that the clamps must be actuated mechanically, namely by rotation on each occasion of the thread guide disc.

For the rotation of the thread guide disc, an appropriate control device is provided. Moreover, the newly laid thread is no logner clamped or is clamped with insufficient force until it is seized by the first needles, so that the thread can easily slide, or be pulled by outside influences, out of the thread position.

Both known thread clamping devices have the disadvantage that, if a thread breaks, which usually occurs at the guide knob, the thread must be pulled out of the knob and rethreading carried out.

There is accordingly a need for a thread clamping device which does not possess parts subject to significant wear, requires no or only an insignificant amount of adjustment, prevents slipping back of the threads out of the thread guide knob after they have been separated from the knitted fabric, and thereby ensures a reliable thread positioning at the commencement of a row of knitting.

According to the present invention there is provided a thread clamping device for a knitting machine, the device comprising a member defining a slide surface for a thread to slide therealong, a respective leaf spring arranged at each of a thread inlet end and a thread outlet end of the surface to engage such thread, and a presser element so resiliently biassed towards the slide surface as to press the thread against the surface.

A thread clamping device embodying the present invention may be operable in conjunction with an extremely dense succession of thread guides at a high knitting speed. The construction of the device is such that it does not require any actuating cams or the like to be fitted onto the machine needle board support or machine frame.

No time is needed for opening and closing the device, and unthreading of the thread when a breakage occurs at the machine thread guide knob is prevented.

The presser element may comprise a tongue bearing in a beading at an upper edge of the member and pressed by a tension spring against the slide surface. Instead of the tongue and the tension spring, however, it is possible to provide a leaf spring fixed to the upper edge of the member.

The slide surface is preferably formed as a channel to provide secure guidance of the thread. In addition, to provide secure guiding and seating of the thread, one or more springs having arc-shaped raised portions may be provided at the inlet and outlet ends of the slide surface.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a partly sectioned front view of a thread clamping device according to a first embodiment of the invention, Fig. 2 is a side view of the device of Fig. 1, Fig. 3 is a partly sectioned front view of a thread clamping device according to a second embodiment of the invention, and Fig. 4 is a side view of the device of Fig. 3.

Referring now to the drawings, there is shown in Figs. 1 and 2 thread clamping device which can be mounted on a knitting machine at any desired position between the thread guide knob and the reel bodies, preferably in the immediate vicinity of the thread guide knob. The device comprises a base member 1 having a slide surface 2 over which a thread 3 can slide, and two open or leaf springs 4 and 5 arranged one at each of the inlet end and outlet end for the thread 3. In the region of the surface 2, an inclined tongue 6 presses on the thread 3. The tongue 6 bears in a beading 7 at an upper edge 8 of the member 1. It is pressed by a tension spring 9, which is connected by a pin 10 with the member 1, against the surface 2 and the beading 7. The force thereby exerted by the tongue 6 on the thread 3 is relatively small.This force is determined by the weight and the angle of attack of the inclined position of the tongue 6 and by the force of the tension spring 9. For guiding and securing the thread 3 and also the tongue 6, the base surface 2 is formed as a channel 11 and the two springs 4 and 5 are each provided with an arc-shaped raised portion 1 2. The thread clamping device is laterally open to facilitate laying in of the thread 3.

During the course of knitting by a knitting machine fitted with the devices, the thread 3 slides, guided by the raised portions 12, along the surface 2 of the member 1. At the edge of a knitted fabric, after the thread 3 has been separated between the thread guide knob of the machine and the end of the knitting or when a needle breakage occurs in the region of the knitting needle, the thread 3 is released for movement in the direction opposite to that in which the thread moves during the knitting operation. However, if the thread is pulled in this opposite direction, the thread 3 attempts to take the tongue 6 with it and thereby becomes jammed between the tongue 6 and the surface 2.Since the thread 3 cannot slide back, the free thread end produced upon cutting of the thread continues to project out from the thread guide knob and can be reliably seized by the needles in the region of the needle board.

If the device is to be used for two or more threads, a corresponding number of arc-shaped raised portions 12 should be provided on the springs 4 and 5, i.e. at each of the inlet end and outlet end of the thread clamping device there is a plurality of springs 4 and 5 with different raised portions 12. In the case of two threads 3 of different diameter, the threads run crossed one over the other in the device to ensure secure tensioning of the thinner thread. In this way the result is achieved that the clamped, thicker thread pulls the thinner thread with it into the clamping.

Instead of the tongue 6, it is also possible, as shown in Figs. 3 and 4, to fix a leaf spring 13 to the upper edge 8 of the member 1 by means of screws 14. As a result, the thread 3 is prevented from movement in opposition to the movement of the thread during the knitting operation. The leaf spring 13 bears against a screw 14.

Claims

1. A thread clamping device for a knitting machine, the device comprising a member defining a slide surface for a thread to slide therealong, a respective leaf spring arranged at each of a thread inlet end and a thread outlet end of the surface to engage such thread, and a presser element so resiliently biassed towards the slide surface as to press the thread against the surface.

2. A device as claimed in claim 1 , wherein the presser element comprises a tongue pivotally mounted on a mounting portion of the member spaced from the slide surface, the tongue being biassed towards the slide surface by a tension spring.

3. A device as claimed in claim 1, wherein the presser element comprises a leaf spring element mounted on a mounting portion of the member spaced from the slide surface.

4. A device as claimed in any one of the preceding claims, wherein the slide surface is provided by the base surface of a channel in the member.

5. A device as claimed in any one of the preceding claims, wherein each of the leaf springs inciudes a curved portion defining a recess for receiving such thread.

6. A device as claimed in any one of the preceding claims, comprising at least one additional such leaf spring at each of said ends of the slide surface.

7. A thread clamping device for a knitting machine, the device being substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

8. A thread clamping device for a knitting machine, the device being substantially as hereinbefore described with reference to Figs. 3 and 3 of the accompanying drawings.

9. A knitting machine provided with a thread clamping device as claimed in any one of the preceding claims, the device being arranged to clamp a thread between a thread guide knob and a reel body of the machine after separation from a knitted fabric.