GB2123738A

GB2123738A - Slitting of flexible sheet material

Info

Publication number: GB2123738A
Application number: GB08319042A
Authority: GB
Inventors: Dennis John Williams; Peter Ginns; Robert John Morley
Original assignee: Courtaulds PLC
Current assignee: Akzo Nobel UK PLC
Priority date: 1982-07-15
Filing date: 1983-07-14
Publication date: 1984-02-08
Also published as: GB8319042D0

Abstract

Fabric 20 formed with a longitudinally extending pocket 21 is slit by a circular blade 9 projecting through an elongate eye 8 in a guide needle 6 engaged in the pocket 21, the fabric being drawn from right to left in Figure 1 by means (not shown). <IMAGE>

Description

SPECIFICATION Slitting of flexible sheet material This invention relates to the slitting of flexible sheet material which has particular, but not exclusive application to the slitting of woven fabric.

According to one aspect of the invention, a method of slitting flexible sheet material formed with a longitudinally extending pocket, comprises locating a guide element within the pocket and effecting relative movement between the guide element and the sheet material to cause the guide element to pass through the pocket and slitting the sheet material with slitting means guided by the guide element in the pocket.

According to a further aspect of the invention, a method of slitting woven fabric comprises forming in the fabric during weaving a pocket extending in the warp direction of the fabric, forwarding the fabric in the direction of the warp towards a guide element engaged in said pocket, slitting said fabric using slitting means associated with said guide element to sever the fabric and drawing off the severed parts of the fabric.

Said slitting means may comprise a heated member fixedly mounted on said guide element.

Alternatively, said guide element may comprise a needle engaged in said pocket and provided with an elongate eye, and the slitting means may be located within the eye of the needle. The slitting means may be a circular blade projecting into said eye. Alternatively, the slitting means may be a heated member guided by the needle.

The invention includes apparatus for slitting woven fabric, the apparatus comprising means for forwarding fabric in the direction of the warp yarns towards a guide element engageable in a pocket extending in the warp direction of the fabric, slitting means associated with said guide element to sever the fabric, and means for drawing off the severed parts of the fabric.

Embodiments of the invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic representation illustrating the essential features of one embodiment of apparatus according to the present invention, Figure 2 diagrammatically illustrates one method of mounting a guide needle in the apparatus of Figure 1 and shows other parts of the apparatus in side view, Figure 3 shows elements of a second embodiment of apparatus according to the invention, and Figure 4 is a diagrammatic side elevation of the essential features of a third embodiment of apparatus according to the invention.

The apparatus for slitting fabric shown in Figures 1 and 2 comprises a pair of nip rollers 5 for forwarding fabric in the warp direction towards a guide element having the form of a needle 6 with a tapering end portion 7. The shank of the needle is provided with an eye or elongated slot 8 and an annular blade 9, slidably mounted on a shaft 10 and drivably connected thereto by a keyway 11, is located so that the cutting edge 1 3 of the blade extends through the slot 8 and projects below the needle 6. A unitary part 1 4 of the needle is mounted in a guide block 1 5 located in a channel 1 6 in which the guide block can move in directions perpendicular to the plane of the paper in Figure 2.The channel 1 6 is mounted in a structure (not shown) such that, when the apparatus is in use, it can be reciprocated forward and back in relation to the direction of movement of the fabric in Figure 2.

A pair of nip rollers 1 7 serve to draw severed portions of fabric away from the needle 6 and blade 9.

The apparatus shown in Figures 1 and 2 is adapted for slitting textile fabric 20 formed with a warpwise extending pocket 21. The needle 6 is introduced into the pocket 21 - and rides therein as the fabric is drawn past the blade 9. Severed portions of fabric are threaded between the rollers 17, the fabric having first been passed between the rollers 5.

In use, the blade 9 is rotated by the shaft 10, the fabric is forwarded to the blade 9 by the rollers 5 and is drawn off by the rollers 17. The needle 6 engaged in the pocket 21 serves as a guide constraining the lateral movements of the blade 9 in relation to the fabric 20 so that the blade 9 cuts the fabric along lines disposed within the pocket 21. A portion of the blade 9 above the needle 6 severs the upper material forming the pocket and a portionof the blade below the needle 6 severs the lower material forming the pocket.

The pocket 21 may be formed by weaving a conventional double fabric so that the upper and lower materials of the pocket comprise woven materials with warp and weft threads. However, one or both of those materials may be constituted only by weft threads.

In an alternative arrangement, an additional cutting blade may be mounted separate from the guide needle 6 so that the fabric is also cut at a location remote from the position of the needle 6 along a line parallel to the line of the pocket 21.

Two guide needles may be provided arranged at or near the lateral edges of the fabric and each arranged to engage in a different longitudinal pocket in the fabric.

In such cases where an additional slitting means is provided, the slitting means mounted in the needle may be arranged to cut both the upper and lower fabrics or weft yarns forming the pocket (as illustrated in Figure 1 ) or only one of those fabrics or sets of weft yarns.

Although the invention is expected to find its most useful applications in the slitting of woven fabric it will be appreciated that any flexible sheet material that can be formed with a suitable guide pocket can be slit by the method and apparatus described.

As an alternative to the cutting blade 9, a heated member comprising an electrically heated wire 25 (Figure 3) may be mounted in a guide needle 26 of heat- and electrically-insulating material. The needle 26 in Figure 3 is mounted on a block 27 located in a siideway 28 for movement laterally of the direction of movement (A) of the sheet material to be slit. The heated wire 25 shown in Figure 3 has portions projecting up and down from the needle 26, but where only one slit is required, one of these projecting portions would not be provided.

The needle 26 is arranged for engagement in a longitudinal pocket of the sheet material in the same way as the needle 6 of the apparatus of Figure 1 and suitable means would be provided to forward the sheet material to the needle 26 and heated wire 25 and to draw off the pieces of severed sheet material.

As in the apparatus of Figure 1, additional slitting means in the apparatus of Figure 2 may be mounted separately from the guide needle or needles. In both pieces of apparatus more than one additional slitting means may be provided in order to slit the fabric along more than one longitudinal line. For example, additional slitting means may be arranged to slit along each longitudinal edge of the pocket 21 in Figure 1 to remove the pocket completely from the sheet material, additional means being arranged, if necessary, to draw off the additional two pieces of severed sheet material produced.

Using apparatus such as that illustrated in the drawing a slit can be made in woven fabric along a line accurately placed to + mm in the fabric. It may be possible to slit accurately alongside a chosen warp end.

The pocket 21 in which the needle 6 or 26 engages need not extend parallel to the warp yarns in a woven fabric but may follow a curved path extending generally in the warp direction. In such a case the severed edges of the fabric will have curved configurations conforming to the curved path followed by the pocket.

In the apparatus shown in Figure 4, a separate needle 30 is introduced into each pocket (not shown) in the fabric to be slit. The fabric follows the broken line 31 in the direction shown by the arrows B, moving over braked rollers (not shown) before reaching the slitting head and onto a drive roller and eventually a take-up roller (not shown) after leaving the slitting head. The fabric passes over a table 32 pivotally mounted on an axis 33 by means of support 34. After leaving the table 32 the fabric moves to a guide bar 35 so located that the straight-line portion of the path 31 of the fabric from the table 32 to the guide bar 35 is located along a chord of an annular disc 36 mounted on a shaft 37 for rotation in the direction of the arrow C. The disc 36 has a peripheral blade and extends through a slot in the associated needle 30.Each needle 30 is supported at its leading end (in relation to the direction of fabric movement), within the associated pocket in the fabric, on the table 32. The trailing end of each needle rests on a step 38 formed in a block 39 carried on an arm 40. The arm 40 is reciprocable to-and-fro as indicated by the arrows D. During movements of the block 39 towards the fabric, the riser of the step 38 engages the rear ends of the needles 30 and pushes them deeper into the pockets in the fabric and during return movements of the block 39, the needles 30 are urged backward by the forward movement of the fabric so that the rear end of each needle continues to abut against the riser of the step 38.

Because forward movement of the fabric is resisted by the braked roller (not shown) the fabric is tensioned between the guides constituted by the table 32 and the bar 35. The disc 36 can thus penetrate right through the upper and lower materials of the associated pocket.

As can be seen from Figure 4, in the apparatus of that Figure, the needles 30 are upwardly inclined at approximately 30C (preferably between 25C and 35 ) to the horizontal and the fabric moves away from the slitting zone at approximately 45 (preferably between 40C and 50 ) to the horizontal.

Claims

1. A method of slitting flexible sheet material formed with a longitudinally extending pocket, comprising locating a guide element within the pocket and effecting relative movement between the guide element and the sheet material to cause the guide element to pass through the pocket and slitting the sheet material with slitting means guided by the guide element in the pocket.

2. A method of slitting woven fabric comprising forming in the fabric during weaving a pocket extending in the warp direction of the fabric, fowarding the fabric in the direction of the warp towards a guide element engaged in said pocket, slitting said fabric using slitting means associated with said guide element to sever the fabric and drawing off the severed parts of the fabric.

3. A method as claimed in claim 1 or 2, wherein said slitting means comprises a member adapted to be heated and fixedly mounted on said guide element.

4. A method as claimed in claim 1 or 2, wherein said guide element comprises a needle engaged in said pocket and having an elongate eye, and the slitting means is constituted by a blade with a circular periphery projecting into said eye.

5. Apparatus for slitting flexible sheet material form with a longitudinally extending pocket, the apparatus comprising means for forwarding fabric in the longitudinal direction towards a guide element engageable in said pocket, slitting means associated with said guide element to sever the fabric, and means for drawing off the severed parts of the fabric.

6. Apparatus as claimed in claim 5, wherein said slitting means comprises a member adapted to be heated and fixedly mounted on the guide element.

7. Apparatus as claimed in claim 5, wherein said guide element comprises a needle having an elongate eye and the slitting means is constituted by a blade with a circular periphery projecting into said eye.

8. Apparatus as claimed in claim 7 including two guides for the fabric so arranged that fabric under tension passing between the guides is located along a chord of said blade.

9. A method of slitting fabric formed with a longitudinally extending pocket, the method being substantially as hereinbefore described with reference to Figures 1 and 2, Figure 3 or Figure 4 of the accompanying drawings.

10. Apparatus for slitting fabric formed with a longitudinally extending pocket, the apparatus being substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2, Figure 3 or Figure 4 of the accompanying drawings.