GB2198155A

GB2198155A - Improvements in warp knitting

Info

Publication number: GB2198155A
Application number: GB08628435A
Authority: GB
Inventors: John Howard Beardsley; Alan Whitworth
Original assignee: FILIGREE TEXTILES Ltd
Current assignee: FILIGREE TEXTILES Ltd
Priority date: 1986-11-27
Filing date: 1986-11-27
Publication date: 1988-06-08
Anticipated expiration: 2006-11-27
Also published as: EP0273591A1; GB2198155B; GB8628435D0

Description

1 - 1 2198155 IMPROVEMENTS IN KNITTING It is known to manufacture a

knitted fabric by forming loops in parallel pillar threads drawn from a warp beam and then locking the loops by inlay threads drawn from an inlay beam. P atterns may be produced by using pattern beams to supply additional threads, each of which is associated with a respective pillar thread as it passes through a pillar beam, the pillar and pattern threads being formed into double loops.

It is also known to provide a knitted fabric with thickened regions by incorporating into the fabric a slub yarn which varies in thickness along its length.

Conventionally the slub yarn is made to run the width of the fabric at right angles to the direction of feed of the pillar threads, in a similar fashion to the weft in weaving. The special slub yarn is expensive and its incorporation into the fabric increases the complexity of the knitting operation.

The present proposal is for a knitting process and a modification to a knitting machine which enables a slub, effect to be produced in knitted fabric without the expense of using slub yarns.

In the drawings:

Figure 1 is a diagrammatic view of a knitting machine 30 modified in accordance with the present proposal; Figure 2 shows diagrammatically rows of stitches formed on the machine; Figure 3 shows a counterweight for an effect beam; - 2 Figure 4 illustrates fabric produced by the method, also enlarged.

Referring to Figure 1 of the drawings, a knitting machine 1 has a warp beam 2 and an inlay beam 3, from which parallel rows of threads 21 and 31 respectively are drawn into the machine and knitted into a fabric. As shown on the right-hand side of Figure 2, the threads 21 are formed into loops which are locked by the threads 31, only a short length of one of which is shown for clarity. The machine described above and the knitting operation which it carries out are conventional and need not be explained in detail.

The machine also includes four effect beams 4, 5, 6 and 7 from which parallel rows of threads 41, 51, 61 and 71 are drawn into the machine. Each of these threads is passed through a pillar bar together with a respective one of the threads 21 and formed with that thread 21 into a series of double loops, as shown in Figure 2 for threads 41 and 51. The effect threads are conventional threads and may be identical to the threads 21 and 31.

The effect beams are rotated as the threads are drawn from them. Each beam is provided at its ends with three, equi-angularly spaced radial arms 8 for balance weights 9. Provided that the three arms of an effect beam are weighted identically, the threads are subjected to a constant tension as illustrated in the case of the beam 4. The threads 21 and 41 are thereby formed into loops of identical size and procduce in the fabric a rectilinear thickened line running in the warp direction.

If the arms of an effect beam are weighted differently, as shown for beam 5, the threads are subjected to tension during the period that the weight counterbalances the pull applied to the threads, i.e. during travel of the weight through the arc A in Figure 3. When the weight is travelling through the arc B in Figure 3, the tension is 5 removed and the effect beam over-runs to some extent. Consequently the loops formed by the threads 51 are looser than those formed by the thread 21 during this period, and the groups of stitches indicated at 10 in Figures 2 and 4 result in localised loosening of the stitches formed by the effect threads, thereby giving the fabric a simulated slub effect. In the remaining regions the effect-threads combine with the threads 21 to provide a thickened line of stitches.

By arranging for a number of the pattern beams to be unbalanced in this way, and for the single weights of all unbalanced pattern beams to be out of alignment, fabric may be produced as illustrated in Figure 4 in which the thickened regions are out of line and enhance the slub effect.

other methods may be employed of varying the tension in the threads drawn into the machine from the effect beams, for example by using a brake or a drive system to control the speeds at which the beams rotate.

Although the machine has been illustrated with four effect beams, the machine may be provided with additional such beams, for example, eight to enhance the random appearance. Moreover, the lengths of the thickened regions 10 may be altered by changing the diameters of the effect beams.

Claims

1. A method of knitting in which warp threads and ef f ect threads are formed together into loops and locked by inlay threads, and the tension in the effect threads is varied so as to cause some of the stitches into which the effect threads are formed to be looser than others.

2. A method as claimed in claim 1, in which the variations in the tension are caused by feeding the effect threads from beams provided with counterweights, the combined centre of gravity of which is spaced from the axis of rotation of the beam.

3. A knitting machine including beams from which effect threads are supplied to the machine, means being provided to reduce or remove periodically the tension in the threads fed from the beams.

4. A knitting machine as claimed in claim 3, wherein the beams are provided with asymmetrically arranged balance weights.

Published 1983 ae 'Eic Patent Office, State House, 66.71 High Holborn, London WC IF. 4711. Fu-mbew oopios zney be obVilned from The Pattan Office, SaIcs 1, -nch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex t-scliniques ltd, Ct Mrqy CraY, KOnt. COn 1/87.