GB2133732A - Fabric cutting device and apparatus - Google Patents

Abstract

A cutting device for cutting moving fabric into widths comprises a cantilever cutting bar means 50, which has at least one reciprocable cutting blade (70 Figure 3). The fabric is guided into a notch 68 in a guide bar, and the blade reciprocates across the notch. Preferably the blade is reciprocated in a pulsed fashion by means of a solenoid 44 and return spring 54, and the solenoid is contained in a casing 34 and the casing and cantilever guide bar and cutting blade can be pivoted as a unit on a mounting bracket 24 which positions the cutting device in relation to the moving fabric. The pivoting of the casing and cantilever guide bar is resisted by holding means such as magnets 100, but the holding means will be overcome when the load and the cantilever guide bar becomes excessive (as a result of malfunctioning or inefficiency of cutting), and the pivoting of the casing operates a microswitch which in turn causes the feed of the fabric to stop. <IMAGE>

Description

SPECIFICATION Fabric cutting device and apparatus This invention relates to a fabric cutting device, especially but not exclusively to a fabric cutting device for cutting knitted fabric. The invention also relates to an apparatus such as a knitting machine provided with one or more devices according to the present invention.

Traditionally, knitted fabric which is produced in flat web form by a flat bed knitting machine, or in tubular form on a circular knitting machine, is first of all cuttransversley into lengths and then the lengths are cut longitudinally of the web or tube by hand by an operator using suitable shears, to cut the lengths into strips of appropriate width for garments to be manufactured from the knitted fabric strips.

This invention is concerned with providing a device for the cutting of the fabric web or tube into the widths or strips as abovementioned, in order to eliminate the conventional hand shearing.

The present invention has a number of novel aspects all of which seek to improve the cutting of fabric webs into widths by cutting the fabric as it is being fed by machinery, the cutting being in the direction of feed of the fabric in that the fabric is fed past or onto the cutting device.

In each case, the device is provided with a reciprocating cutting blade means which extends cantilever fashion from a mounting means so as to intersect the fabric transversely of its direction of travel. Reciprocation of the cutting blade means coupled with the feed of the fabric effects the cutting of the fabric into widths.

In accordance with a first aspect of the present invention, the cutting device is associated with sensing means adapted to sense malfunctioning or deterioration of effectiveness of cutting of the cutting blade means, such sensing means being adapted to cause feed of the fabric web to stop in such circumstances.

The sensing means may comprise means sensing a bunching of fabric at the cutter blade means, or an increase in the force imparted by the fabric on the cutter blade means by virtue of the feeding of same.

The means mounting the cutter blade means may bea casing which istiltable mounted on a bracket, which is in turn fixed in relation to the machinery moving the fabric web, there being a holding means holding the casing and bracket from tilting until a predetermined loading on the cutter blade means by the fabric is exceeded, which results in the overcoming of the holding means, and the casing can tilt thereon.

The holding means may comprise a single magnet or a pair of magnets, and although other releasable holding means may be employed, it is felt that a pair of magnets is the most suitable, as the magnetic attraction between the magnets can be varied by relative displacement between the magnets, whereby the release force can be any predetermined value within the range of the mutual attraction of the magnets.

The cutter blade means may comprise a movable cutter blade contained in a guide, the guide having a fabric retention notch into which the fabric feeds and across which the blade reciprocates.

The blade may be reciprocated by means of a solenoid, pulse driven, which is contained in the casing, and the casing, solenoid, and cutter blade means may be removable from the bracket for replacement and/or repair.

In accordance with a second aspect of the invention, the cutting device for cutting fabric comprises a guide for receiving the edge of the fabric, and in the guide, there is a reciprocable cutting blade connected to means for reciprocating the blade back and forth to cut the fabric introduced into the guide.

The guide may be in the nature of a plate or plate-like body provided with a notch leading from one edge of the body to a position inwardly spaced therefrom, the notch being trumpet-shaped so that it is widest where it meets the edge of the body and is narrowest inwardly of the said edge, the blade being arranged to traverse the said notch during its reciprocation, and the notch being dimensioned in relation to the fabric to be cut so that at its narrowest, it is approximately the same thickness as the fabric, and the blade being arranged to traverse the slot at this narrow thickness region to ensure the stable retention of the fabric whilst it is being cut.

The guide and cutter may be arranged so as to be capable of adjustment so that the guide slot and cutting blade may be located closet two our further from the casing, and the bracket will preferably be mounted on the machine so as to be capable of lateral or circumferential adjustment in order to vary the size of the fabric widths which are cut. In this connection, any one machine may be provided with a plurality of devices according to the invention, and in a circular knitting machine, the device may be arranged on a circular support bar which encircles the tube being produced by the machine.

In another aspect of the invention, there is provided a cutting device for cutting the fabric web or fabric tube into strips comprising a casing housing a prime mover and provided with cantilevered cutting means, said device being provided with means adapting it for mounting on a machine for producing the fabric, with the cantilevered cutting means intersecting the direction of travel of the fabric for producing a longitudinal cut therein.

The invention also extends to fabric producing machines provided with devices as aforesaid.

An embodiment ofthe invention will now be described, by way of example, with reference to the accompanying drawings, wherein:- Figure 1 is a perspective view of a cutting device according to the invention; Figure 2 shows the device of Figure 1 in side elevation not with a different mounting ciamp; Figure 3 shows an exploded perspective view and to an enlarged scale, the cutting blade and guide arrangement; Figure 4 is a sectional elevation taken on the line X-X in Figure 3; Figure 5 is a diagrammatic illustration of a circular knitting machine, showing how a plurality of devices according to Figures 1 to 4 are arranged to cut the tubular fabric being produced on the machine into strips.

Figures 6(a) and 6(b) are circuit diagrams showing respectively and diagrammatically how the cutting devices on a single knitting machine and several knitting machines are controlled.

Referring to the drawings, and firstly to Figure 5, a circular knitting machine is illustrated diagrammatically, and the knitting head thereof is represented by the numeral 10, its circular travel being represented by the arrows 12. The circular fabric which is being produced in the machine is represented by numeral 14, and the direction of feed ofthetubularfabric is represented by the numeral 16.

Such machines are well known and are in extensive use. In order to produce strips of knitted fabric for the production of garments, the tubular fabric is cut longitudinally, and traditionally this has been done manually using hand shears. This invention has as an object thereof to make the use of shears unnecessary, and to this end the machine illustrated in Figure 5 is provided with a plurality of cutting devices 18, mounted on a circular support bar 19 which surrounds the fabric 14, in order to cut the fabric into strips 20 as the fabric travels past the cutting devices 18. The devices 18 are mounted so as to be circumferentially adjustable in position on the support 19, so that the width of the strip 20 may be varied to suit their end use.The cutting part of the devices 18 mat also be adapted to be adjustable in position as indicated by reference arrows 22, to suit the size of knitting machines on which the tubular fabric is being produced.

Referring now to the other Figures, one of the cutting devices 18 is shown in perspective view in Figure land in side elevation in Figure 2. The device comprises a mounting bracket 24 made up of a formed plate, and at one end the bracket 24 is provided with V-notches 26 in which the mounting bar 19 is located. A clamp rod 28 extends through the bracket 24, and is provided with a curved clamping shell 30 which encircles the rod 19. In Figure 2, a modified clamp bar 23 and clamp 25 are provided to enable device 18 to be clamped to a rod 27. The clamping rod 28 at its other end has a clamping nut 32, which reacts against an internal partition 33 inside the bracket 24.By tightening the nut 32, so the bracket 24 is clamped onto the rod 19, and to remove the bracket 24 it is simply a matter of unloosening the nut 32so that the shell 30 or clamp 25 can be removed from rod 19 can be removed from the notches 26.

Pivotally mounted on the bracket 24 is a casing 34 which is so mounted by having lugs 36 with apertures therein, which register with apertures in the sides of bracket 24, and through the alinged apertures is a rod 38 defining the axis of pivoting between the casing 34 and bracket 24. Rod 38 has an extension portion 40 which lies to one side of the casing 34, a top portion 41 which extends over the top of the casing, and a tail portion 42 which wraps round the other side of the casing. This rod assembly 38 to 42 is so constructed that in use the rod portion 38 is prevented from vibrating out of the aligned apertures in lugs 36 and the sides of bracket 24, by virtue of the tail portion 42 catching on the casing 34.

The casing 34 houses a solenoid 44, the armature 46 of which is connected to a reciprocable blade bar 48, which can reciprocate in a cantilevered guide 50 as will be explained herein. The armature is connected to bar 48 by means of a pivot pin 52, and a spring 54 serves to urge the armature to a right hand or forward position shown in Figure 2.

The solenoid is energised by means of a suitable power supply 56 which can be plugged into a socket connection 58 attached to the underside of the casing, and the casing also has a further input 60 for receiving a jack plug 62 for delivering output signals via wire 64 to the knitting machine to stop same in certain circumstances, as will be explained hereinafter.

Plug 56 is connected to a control box as will be explained.

At the end of the guide 50 there is a notch 68 for receiving, edge on, the fabric 14, and inside the guide 50 is a cutting blade 70 (Figure 3) which is reciprocated in use via the cutting blade bar 48 and the solenoid 44.

In the event that the advance of the web 14 as indicated by arrow 16 is retarded due to malfunctioning or a deterioration in efficiency of cutting by the blade 70, so the increase in force on the end of the guide 50 will cause the casing 34 to tilt slightly about the pivot rod 38, which has the effect of operating a microswitch normally held closed by the relative positioning of the casing 34 and bracket 24, and an electrical signal is sent instructing the knitting machine to stop. The device includes means for resisting the tilting and such means comprises at least one magnet 100 which is carried by the partition plate 34 of the bracket 24. The magnet holds the casing 34 magnetically to the bracket, and the attraction between the magnet 100 and the casing (or another magnet mounted thereon) must be overcome before the casing can tilt to motivate the inner switch.This is to ensure that the casing will not simply tilt against the normal force applied on the end of the cantilever guide 50 with the normal travel of the fabric 14 past the cutting blade.

Alternative holding means may be provided. The magnetic holding means may be capable of adjustment so that the holding force therebetween may be adjusted to suit the type of fabric being cut. During this tilting operation, the bar assembly 38, 40, 41 and 42 does not change position relative to the casing 34.

It it is desired however to disconnect casing 34 from bracket 24, the rod assembly 38 to 42 is moved to the dotted line position A in Figure 1, and then is pulled linearly as indicated by arrow B in Figure 1 until the rod assembly is in position C in Figure 1, and the casing 34 can therefore simply be lifted from bracket 24 for replacement and repair.

Reference is now made to Figures 3 and 4, and detail of the design of the cutter at the end of the cantilever guide 50 will now be described.

In Figure 3 the outer end of the cutter support bar is shown, and it will be seen to have a recess 72 for receiving a shank end 74 of the cutter 70. The shank end is connected by means of screws 76, and the cutter has a blade end 78 which projects from the outer end of bar 48 when the cutting blade 70 is attached thereto.

The guide 50 is made up of two parts namely a bar 80 having a recess portion 82 to receive the bar 48 slidably, and a narrow slot 84 for receiving the cutting blade portion of the blade 70, and a cover plate 86 which is secured to the bar 80 by means of suitable screws passing through holes 88 in plate 86 and being threaded in threaded holes 90 in bar 80.

Cover plate 86 closes the slots 82 and 84 so that, as shown in Figure 4the bar 48 and the blade 70 are constrained from moving laterally when reciprocating.

The notch 68 is formed in each of the bar 80 and cover plate 86, and as can be seen it is generally trumpet shaped extending from a wide mouth region 92 at the top edge of the guide 50, to a narrow region 94, which is approximately equal to the thickness of the fabric at the end of the notch which is located inwardly of the top edge of the guide. The portion 94 is inclined slightly rearwardly, and the mouth 92 is curved smoothly in two directions as shown.

The blade portion 78 of the blade traverses the portion 94 of the slot and is reciprocated therein during operation of the device. The heads of the screws 76 are located in an aperture 96 of plate 86 so that the blade 70 can reciprocate freely, and also so that the screws can be removed through the aperture 96 to permit removal of the blade 70 out of the end of slot 84.

An aperture 98 is provided in bar 80 leading into recess 82 so that fly and other particles which collect in the recess 82 can be removed when the blade 70 is detached from the end of bar 48.

By housing the bar 48 inside the guide 50 so that it is constrained from moving laterally, so maximum control of reciprocation of the blade 70 is achieved. It should be noted that the blade 70 is double sided in that it has a cutting edge at the top and at the bottom and can be reversed when one of the cutting edges is blunt, but single sides blades can also be used.

In operation of each device, the blade 70 is reciprocated across the portion 94 of notch 68 whilst the fabric 14 is fed therethrough. The solenoid 44 is driven from a suitable electrical supply (56) through control circuit 66 which causes pulsing of the solenoid 44 at a suitable frequency, typically three cycles per second. The pulsing frequency is capable of adjustment, preferably between 1 and 3 cycles second. Return of the solenoid to the advanced position is achieved by the spring 54.By the design of the device described, it has been found that effective and even cutting can be achieved, but should the efficiency of cutting deteriorate, or should there be a failure or malfunctioning so that there is no cutting, the increase in force on the end of the cantilever guide 50 will cause movement of the casing about the pivot rod 38, and operation of a limit switch will cause through the signal output 64 stopping of the knitting machine. The sensing of malfunctioning of deterioration of cutting can be determined by other means, such as by sensing the bunching of fabric in the region of the notch 68 by thickness sensors, or the retardation in feed of fabric, and this is an important aspect of this embodiment of the invention.

It is possible to use prime movers other than solenoids. By using a single trigger circuit for several cutting devices it can be arranged that the cutting action in the respective devices is sequential which avoids abnormal loading on the transformer.

Although the arrangement described comprising a single blade reciprocable in a fixed guide has distinct advantages, in the aspect of the invention which comprises sensing of abnormal operation, multiple reciprocable cutting blades can be used.

Referring now to Figures 6(a) and 6(b) these Figures illustrate diagrammatically how the control signal is derived from the devices 18 for the stopping of the knitting machine. In the arrangement shown in Figure 6(a), a plurality of the devices 18 are shown connected to control box 101 which is supplied with mains electricity via a supply cable 103. A primary stop motion signal cable 105 leads to the knitting machine drive, and the arrangement is that when one of the devices 18 is malfunctioning, a signal is sent over line 56 to the control box, which in turn emits a signal via line 105 to the knitting machine, causing same to stop.

In the arrangement of Figure 6(b), the electrical connections are shown for coupling three separate machines each provided with a plurality of the cutting devices 18. Machine No. 1 is controlled as described above via the control box 101 and the lead 105, but as regards the second and third machines, the devices 18 are coupled via the control signal line 64 (already described) which in turn controls the stopping and starting of the knitting machine. Thus as regards either Machine No. 2 or Machine No.3, if any of the devices 18 operating therewith malfunctions as described herein, a signal is sent over line 64 to stop only that machine.

All three machines are coupled to the same control box 101.

Claims (14)

1. A cutting device provided with reciprocating cutter blade means which extends cantilever fashion from a mounting means so as to intersect a moving fabric transversely of its direction of travel, and wherein the cutting device is associated with sensing means adapted to sense malfunctioning or deterioration of effectiveness of cutting of the cutting blade means, such sensing means being adapted to cause feed of the fabric web to stop in such circumstances.

2. A cutting device according to Claim 1, wherein the sensing means comprises means sensing bunching of fabric in the region of the cutter blade means.

3. A cutting device according to Claim 1, wherein the sensing means comprises means sensing an increase in the force imparted by the fabric on the cutter blade means by virtue of its movement.

4. A cutting device according to Claim 3, wherein the means mounting the cutter blade means comprising a casing which is pivotally mounted on the bracket, which bracket is fixed in relation of the machinery moving the fabric web.

5. A cutting device according to Claim 4, wherein there is a holding means holding the casing and bracket from pivoting until a predetermined loading on the cutter means by the fabric is exceeded, which results in the overcoming of the holding means, and the casing can pivot thereon.

6. A cutting device according to Claim 5, wherein the cutter blade means swings clear of the fabric in the event of a predetermined loading on the cutter blade means being exceeded.

7. A cutting device according to Claim 5 or 6, wherein the pivoting of the casing on the bracket results in operation of a microswitch which is used to signal to the machinery feeding the fabric.

8. A cutting device according to any preceding Claim, wherein the cutter blade means comprises a movable cutter blade contained in a guide, the guide having a fabric retention notch into which the fabric feeds and across which the blade reciprocates.

9. A cutting device according to Claim 8, wherein the blade is reciprocated by means of a solenoid of which the armature is connected to a cutter blade mounting bar, and the solenoid is pulse driven, and is returned to an initial position by spring means.

10. A cutting device for cutting moving fabric into strips by means of a cutting blade means which intersects the direction of travel and cuts by the reciprocation of a cutter blade transversely of the fabric, wherein the cutter blade is contained in a guide, and the guide has a notch into which the fabric feeds.

11. A cutting device according to Claim 10, wherein the guide comprises a bar containing a slot or recess in which the cutting blade is contained, and the slot or recess is closed by a cover plate, the said cover plate and bar having the notch therein.

12. A cutting device according to Claim 10 or 11, wherein the said notch is trumpet shaped defining a wide mouth at the edge of the guide and a narrow throat of width approximately equal to the thickness of the fabric inwardly of the edge of the guide, and across which throat the cutting blade reciprocates.

13. A cutting device according to any of Claims 10 to 12, wherein the cutting blade is completely enclosed by the guide.

14. A cutting device substantially as hereinbefore described with reference to the accompanying drawings.