GB2171120A - Improvements in or relating to circular knitting machine - Google Patents

Abstract

A circular knitting machine has a wrapping mechanism including a plurality of yarn conduits (22) each mounted on members (14, 20), the member (20) having a projection (32) engageable with a cam track to pivot the conduit (22) outwardly and upwardly and the member (14) having a projection engagable with another cam track to pivot the members about a vertical axis (12) to wrap the yarn round selected needles (2). A horizontal striping mechanism (8) may also be provided. By enabling the yarn conduit (22) to partake of vertical movement it is possible to introduce the conduit directly into an operative position, and then readily to lower the conduit to an out-of-the-way position so that for example an adjacent wrapper may be brought into action at the earliest subsequent point or the stationary striper mechanism (8) may operate unhindered.

Description

SPECIFICATION Improvements in or relating to circular knitting machine The invention is concerned with improvements in or relating to circular knitting machines, particularly machines provided with a wrap facility.

Circular knitting machines incorporating wrap mechanisms are capable of producing vertical bands of knitted yarn in the knitted fabric, the yarn having selected characteristics such as colour contrasting with the characteristics of the yarn comprising the ground fabric. Conventionally, such mechanisms comprise independently movable wrapping levers, each of which is arranged to wrap a warp thread around a single needle or a small group of adjacent needles in the circle of needles.

Each wrapper is arranged to be advanced from a rest position within the circumference of the needle circle, across the line of needles to feed the yarn around, say, a single needle raised for that purpose and radially inwards of the needle line to return to its rest position.

Such movements are conventionally controlled by cam arrangements positioned within the circumference of the needle circle so as to initiate the desired movements in a substantially radial plane by means of pins or the like provided on the wrappers which follow the tracks in the cam plate.

The invention provides a circular knitting machine having a wrapping mechanism comprising a yarn carrying means adapted to carry yarn to the vicinity of selected needle or group of needles in a cylinder of the machine, said carrying means being mounted upon a body member arranged for motion in a vertical plane with respect to the needle cylinder axis, said body member being further arranged for motion having a radial component of movement.

Advantageously, the radial motion of the wrapper body member includes a pivotal motion occurring about an at least substantially horizontal axis.

Conveniently the body member is capable of a limited degree of rotation about a vertical axis passing therethrough or closely adjacent thereto.

By enabling the yarn carrying means to partake of vertical movement heightwise of the machine, it is possible to introduce the yarn carrying means directly into an operative position, and then readily to clear the yarn carrying means to a rest position by causing it to be lowered to an out-of-the way position so that for example an adjacent wrapper may be brought into action at the earliest subsequent point in the knitting operation.

It will be appreciated that the invention is applicable to a large range of sizes of circular knitting machines including the so-called small diameter machines where the diameter is no more than approximately 86 cm (22"). Such machines may or may not be equipped with striper mechanisms for producing knitted horizontal (coursewise) stripes in the fabric.

Where machines include wrapper facilities according to the invention, advantages of economy of movement are obtained together with those of improved performance, reliability and avoidance of damage or undue wear caused by impact of moving parts during operation. Where striper mechanisms are present, still further advantages accrue as will be apparent from the present specification. Machines incorporating devices of the present invention benefit from the smoothly operating cam track flow possible with the wrapper movement as herein described. It will be understood that the speed of operation of modern.knitting machinery precludes the provision of steep angles and inclines in cam tracks.

The invention further provides a circular knitting machine having at least one wrapping mechanism comprising a yarn carrying means adapted to carry yarn to the vicinity of a selected needle or a group of needles in a cylinder of the machine and at least one striper mechanism arranged to provide yarn to needles of the cylinder, wherein each yarn carrying means is mounted upon a body member arranged for movement in a vertical plane with respect to the needle cylinder axis, said body member being further arranged for pivotal motion having a radial component of movement, the construction and arrangement being such that after operation of the wrapper mechanism, the associated yarn carrying means is lowered with respect to the machine to a level beneath that of the or each stationary striper mechanism as it operates.

In preferred examples of machines according to the invention the arrangement is such that the wrapping mechanisms rotate in the machine with the selected needle or group of needles, selection of needles chosen within the group for presentation to accept yarn from the wrapping mechanism being cpable of being varied at successive operating regions around the circumference of the machine.

The invention thus permits the use for the first time of a circular knitting machine equipped with a large number of striping mechanisms, for example forty four, to provide fully engineered horizontal (course-wise) stripes in a fabric, said stripes having a "solid" appearance since they may comprise a relatively high number of courses compared with the total number of courses knitted at each revolution of the machine rather than being restricted to merely one or two courses per revolution, the machine being also equipped with a plurality of wrapping mechanisms to provide vertical (walewise) bands, thus increasing the variety of checked and fully engineered striped patterns available for fabric design.

In the present specification, the term "fully engineered" is used to refer to the production of horizontal striped effect by the use of striping mechanisms which may be used selectively during the production of fabric, being controlled by conventional selection arrangements to produce visual variations between different regions of the fabric as the regions are knitted in sequence. Thus a first knitted region may for example include a number of horizontal stripes followed by a nonstriped region knitted without any of the striping mechanisms being selected. This contrasts with a machine which has no additional striping mechanisms but which may be arranged to produce a horizontally striped fabric by setting the machine up with contrasting yarns supplied to the needles at alternate feed stations or groups of stations.Once the feeds are set up, such a machine produces the appropriate striping pattern consistently and this cannot be changed during the knitting operation.

It will be appreciated that where each wrapper mechanism of a machine operates on only a small number of needles, only a narrow vertical band is obtained. Where a larger number of needles, say twelve to sixteen, may receive a wrapped yarn as in a machine according to the present invention then the vertical bands may of course be designed so as to be appreciably wider. This will give much greater scope for fabric design in the context of the present invention.

The invention therefore further provides a machine as described in the fourth paragraph or the ninth paragraph of this specification wherein the yarn carrying means partakes of a movement comprising a) an advancing stage having a component of outward radial movement with respect to the central vertical axis of the machine and a component of upward movement, thus bringing the outlet of the yarn carrying means from a position within the circle of needles in the cylinder to a position external thereto, b) a stage during which the needles are in a raised position through the action of cams and are moving in the direction of the knitting operation of the machine and during which the said outlet moves along the circumference of the circle of needles and passes externally of a selected number thereof and c) a retracting stage having a component of inward radial movement and a component of downward movement to return the yarn carrying means to a position within said circle of needles.

Advantageously, during step (b) above, the outlet of the yarn carrying means may move in a direction opposite to said operating direction of the machine.

There will now be described an example of a machine according to the invention. It will be understood that the description which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 shows a cross-sectional view through a portion of a circular knitting machine illustrating one wrapping mechanism according to the invention and its location relative to knitting instrumentalities and striper mechanisms; Figure 2 shows, to an enlarged scale, a yarn carrying means of the wrapping mechanism in Figure 1; Figure 3 shows a horizontal stripe yarn placer of the machine of the present example; and Figure 4 is a plan view in the direction of arrow A of Figure 1.

The Figures show portions of a circular knitting machine which relate to the present invention.

Figure 1 shows needles 2 (only one visible) of a needle cylinder 4, a wrapper assembly indicated at 6 and a conventionally operating striper box 8.

A rotating plate 10 in the machine is provided adjacent its outer edge, that is, its edge remote from the central axis of rotation of the machine, with a plurality of apertures in individual ones of which are received a pivot pin 12 of each wrapper body member 14 of the assembly 6. The body member is held captive by a spring clip 16 which also exerts a damping effect on the operation of the assembly 6.

The body member 14 is provided with a horizontal pivotal mounting 18 for an arm 20 on which is mounted a yarn carrying means in the form of a tubularyarn conduit 22.

A pin 24 projecting from an upper surface of the body member 14 is received in cam track 28 of a cam plate 26. A second cam track 30 is provided in the plate 26, in which track 30 is received a projection 32 provided on an upper portion 34 of the arm 20. In this example, the projection 32 is in the form of a butt extending widthwise of the track 30.

The cam plate 26 is mounted upon a stationary support member 36. The rotation of the plate 10 about the machine axis is determined by the operating rate of the machine.

Also provided is a stationary plate 45 supporting a plurality of striper boxes 8 with their yarncontrolling fingers 38 (shown in a diagrammatic manner in Figure 1) which operate conventionally in the machine to provide horizontal stripes in the knitted fabric. There are in the present example, forty four such striper boxes in a circular array around the machine described in this example. Each may be selected operate as required to produce the desired width of stripe or may be left inoperative where appropriate.

The operation of the wrapper assembly 6 will now be described:Figure 1 shows the yarn conduit 22 in its retracted position in full lines and in its extended position in chain-dotted lines. Figure 4 shows the conduit 22 in three positions A, B, C (in plan view) taken up during its movement between its retracted positions (A) and (C) and its extended position (B) as the wrapper body members 14 move past the cam tracks 28 and 30 and operate the pin 24 and the projection 32 in the manner described below.

In the retracted position of the conduit it will be observed from Figures 1 and 4 that the conduit outlet 40 is within the circle of needles 2 at a level below the operation of the fingers 38 of the striper box 8. Under the control of the cam track 30 acting on the projection 32, the arm 20 pivots about the pivot line 18 so as to swing the arm upwards and outwards (to the right as viewed in Figure 1) until it reaches the extended position. Meanwhile conventional cams (not shown) have raised a selected group of needles, numbering, say up to sixteen, and the conduit 22 in its extended position overhangs the needle 2 so that the outlet 40, through which a yarn Y is supplied via a supply tube 42 and a yarn feed tensioner (not shown), is positioned outside of the line of needles and is able to feed yarn to their open hooks.

In order to achieve the feeding of the yarn to the selected group of needles 2, the cam track 28 causes the body member 14 to partake of a short movement anti-clockwise (as viewed in Figure 4) around the pivot pin 12 in the rotating plate 10. This causes the outlet 40 to pass the yarn across the selected wrap needles so that as they are lowered by conventional cams (not shown) the yarn is received in their hooks. This is best seen in Figure 4 in position B of the conduit 22 with movement taking place in the direction of arrow D.

Once the yarn Y has been fed (C), the cam track 30 causes the butt 32 to move rapidly outwards of the machine to draw the conduit inwards (the needles now have been lowered) and downwards (arrow E).

The cam track 28 then causes the body member 14 to swing clockwise (arrow F) into its retracted position (A).

The advantage of rapid lowering of the conduit 22 is particularly important with respect to the arrangement of the present example where the action of the wrapper assembly intervenes between that of striper fingers 38. The fingers 38 are able to be fully operated at a level above that of any adjacent wrapper mechanism. Thus in the present arrangement as best illustrated in Figure 4, each cam plate 26 is flanked by a plate 44 which includes straight sections of tracks 28 and 30 which maintain the wrapper at a low level while passing beneath the striper fingers 38.

If desired, the plates 44 may be removed or repositioned in the cam plate layout to give versatility according to operational requirements to make the most effective use of the number of yarn feed positions available on the machine and to enable an increase in fabric production. If desired the wrapper mechanism may be rendered inoperative by replacement of the appropriate cam plates. It is clearly advantageous to be able to isolate machine instrumentalities in this way rather than being obliged to strip down the machine when other conversions or operational arrangements are required.

It is thus possible to arrange wrapper assemblies and striper boxes to operate at a variety of selected positions around the circle of needles.

It will be understood that the rotating plate 10 may be utilised to support a conventional yarn placer member 46 (Figure 3) at a position appropriate to the striper finger operation and intervening between the wrapper assemblies.

Various modifications may be made within the scope of the invention, as defined in the following

Claims (11)

claims. CLAIMS

1. A circular knitting machine having a wrapping mechanism comprising a yarn carrying means adapted to carry yarn to the vicinity of a selected needle or group of needles in a cylinder of the machine, said yarn carrying means being mounted upon a body member arranged for motion in a vertical plane with respect to the needle cylinder axis, said body member being further arranged for motion having a radial component of movement.

2. A machine as claimed in claim 1 wherein the radial motion of the wrapper body member includes a pivotal motion occurring about an at least substantially horizontal axis.

3. A machine as claimed in either one of claims 1 and 2, wherein the body member is capable of a limited degree of rotation about a vertical axis passing therethrough or closely adjacent thereto.

4. A circular knitting machine having at least one wrapping mechanism comprising a yarn carrying means adapted to carry yarn to the vicinity of a selected needle or a group of needles in a cylinder of the machine and at least one striper mechanism arranged to provide yarn to needles of the cylinder, wherein each yarn carrying means is mounted upon a body member arranged for movement in a vertical plane with respect to the needle cylinder axis, said body member being further arranged for pivotal motion having a radial component of movement, the construction and arrangement being such that after operation of the wrapper mechanism, the associated yarn carrying means is lowered with respect to the machine to a level beneath that of the or each stationary striper mechanism as it operates.

5. A machine as claimed in any one of the preceding claims wherein the wrapping mechanisms rotate in the machine with the selected needle or group of needles, selection of needles chosen within the group for presentation to accept yarn from the wrapping mechanism being capable of being varied at successive operating regions around the circumference of the machine.

6. A machine as claimed in any one of the preceding claims wherein the yarn carrying means partakes of a movement comprising a) an advancing stage having a component of outward radial movement with respect to the central vertical axis of the machine and a component of upward movement, thus bringing the outlet of the yarn carrying means from a position within the circle of needles in the cylinder to a position external thereto, b) a stage during which the needles are in a raised position through the action of cams and are moving in the direction of the knitting operation of the machine and during which the said outlet moves along the circumference of the circle of needles and passes externally of a selected number thereof and c) a retracting stage having a component of inward radial movement and a component of downward movement to return the yarn carrying means to a position within said circle of needles.

7. A machine as claimed in claim 6 wherein during step (b) thereof, the outlet of the yarn carrying means moves in a direction opposite to the operating direction of the machine along said circumference.

8. A machine as claimed in any one of the preceding claims wherein the yarn carrying means comprises a conduit in the form of a tube.

9. A machine as claimed in any one of the preceding claims wherein the movement of the body members supporting the yarn conduits are controlled by a cam plate arrangement comprising a plurality of readily interchangeable cam plates thus permitting varied distribution of striper mechanisms in the machine.

10. A machine as claimed in claim 9 wherein the cam plates controlling the body members are positioned in the cam plate arrangement together with cam plates adapted to control yarn placer members.

11. A circular knitting machine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.