IE45814B1 - Knitting machine mechanism - Google Patents

Abstract

The gearwheel (14) is rotated at the end of each run of the cam carriage. As a result of this rotation, the supporting arm (5) is pivoted into one of two positions. The holding-down devices (30) fastened slidably to the supporting arm (5) are pressed against the knitted fabric by springs (25). Depending on the direction of movement of the cam carriage, one holding-down device or the other comes into use.

Description

This invention, relates to a flat knitting machine fitted with a presser foot mechanism. A flat V-bed machine having such a mechanism is described, for example, in British Patent Specification lilo. 1,288,043.

When using a presser foot as described in Specification No. 1,288,043, difficulties are sometimes encountered because the presser foot is fixed at a given height in relation to the needle beds and cannot ride up over even a small obstruction or adjust itself to a level appropriate for different types of knitted structure.

To overcome the problems experienced when a presser foot at a fixed level encounters an obstruction such as a broken needle, it has been proposed to mount the presser foot on a support which can rise up relative to the needle beds and the cam carriage, and which, in doing so, will operate a switch to stop the machine.

It has now been found that it is advantageous to mount the presser foot so that it can ride up in relation to the support by which it is mounted on the cam carriage and to arrange that the presser foot is resiliently urged downwardly between the needle beds so that it will press down on the knitted fabric and will rise up to a level determined by. the resistance afforded it by that fabric.

According to the invention, a presser foot assembly for a flat knitting machine comprises a support mountable on the machine for movement along the needle array,· a supporting arm carried on said support, at least one presser foot mounted on said supporting arm for guided displacement in relation to said - 2 45814 supporting arm, and resilient means arranged to urge the presser foot or presser feet in a direction away from said support.

The presser foot or presser feet may he fixed to a part slidably mounted in relation to said supporting arm and said resilient means may comprise one or more springs. The slidably mounted part may be located in a channel on said supporting arm and may be retained in the channel by a plate which covers the channel.

The invention will be further described, by way of example, with reference to the accompanying drawings in which:Figure 1 is an elevation, sectional on the line B-B of Figure 3, of a presser foot assembly according to the invention and also shows some parts of a support for mounting the presser foot assembly on a cam carriage, Figure 2 is a section on the line A-Λ of Figure 1, Figure 3 is a side view of the presser foot assembly of Figure 1, a3 viewed from the plane G - C, and sectional in that plane, and Figure 4 is a view in the direction of the arrow Ό in Figure 3, The presser foot assembly shown in the drawings comprises a supporting arm 5 pivotally mounted on a supporting plate 6 by means of a stud 7 on which it is secured by a circlip 8.

The arm 5 has wings 9 formed with arcuate surfaces 10 for co-operation with a cut-away boss 11 and is slotted at 12 for co-operation with a pin 13 on a toothed wheel 14 of a Geneva gear mechanism. The wheel 14 is rotatably mounted on a stud - 3 45814 secured on the plate 6 and, when the presser foot assembly is mounted in a knitting machine, is rotated at the end of each traverse of the cam carriage by a rack (not shown). Such rotation of the wheel 14 causes pivoting movement of the arm 5 to an alternative position appropriate for movement of the presser foot assembly, together with the cam carriage, in the opposite direction along the needle beds of tha knitting machine.

A spacer 18 surrounds the part of the stud 15 Which I . projects out of the plate 6 and a washer 19 spaces the Wheel 10 14 from the plate 6.

Slidable in. a channel 20 formed in the arm 5 is a slider 21 which has a slot 22 to allow passage through it of the stud 7. The slider 21 is retained in the channel 20 by the plate 6. At its upper end, the slider 21 is formed with.. shoulders 23 and at the upper end of the channel 20 are projecting abutments 24. Between each shoulder 23 and the corresponding abutment 24 is located a helical spring 25. The springs 25 urge the slider 21 downwardly in Figure 1 until the shoulders 23 each abut against a corresponding ledge 27 in a side wall of the channel 20.

On the lower end of the slider 21 is mounted a pair of ' presser feet 30. The presser feet are rigidly carried on a blade 31 made of a carbon fibre composite and the blade is secured on the slider 21 as follows :25 A thinner end portion 32 of the blade 31 is pierced by three holes and lies between a lip 33 on the slider 21 and a thickened end portion 34 on a cover plate 35. Three studs 36 set in the end portion 34 extend through the holes in the portion 32 of the blade 31 and thus secure the blade. The two - 4 45814 outer studs 36 extend into holes 37 in the lip 33 but the centre stud 36 is shorter and merely abuts against the surface of the lip 33.

The cover plate 35 has two pins 38 which, extend through 5 holes 39 in the slider 21 and locate the cover plate on the slider. The pins 38 project from the slider 21 and are slotted to receive the arms of a plate 40 which locks the cover plate 35 on the slider. A hole 41 in the cover plate 35 accommodates the head of a stud 42 carrying the plate 40. A circlip 43 locks the stud 42 and plate on the slider 21.

When the cover plate 35 is located on the slider 21, the end portion 34 is spaced from the lip 33 by a distance greater than the thickness of the end portion 32 of the blade 31 so that the blade has some movement between the end portion 34 and the lip 33 to allow the presser feet some lateral movement between the needle beds of the knitting machine.

In Figure 1, the left-hand, lower presser foot 30 is in its operative position to push down knitted fabric. The height of the support (not shown) of which the plate 6 is a part is adjusted so that when the presser foot meets knitted fabric held on the needles it will ride up slightly from the position shown in Figure 1, this movement being possible because of upward sliding movement of the slider 21 in the channel against the resilience of tha springs 25. The upward limit of movement is governed by abutment of a shoulder 46 on the slider against the lower end 47 of the arm 5.

Within its limits of movement, the presser foot thu3 _ 5 _ 58 14 exerts resilient pressure on the knitting and if the knitting machine is a double system machine, in which case «pairs of presser feet mounted as described above, on a common support, are provided, one pair for each system of knitting cams, then each of the two presser feet operative during any traverse can adjust to different heights in relation to the needle beds.

This is important because the trailing operative presser foot in any traverse acts on knitted fabric containing one additional course compared with the leading presser foot since the leading presser foot co-operates in the formation of that additional course.

In the presser foot assembly described above with reference to the drawings, the length of the slot 22 may be varied according to the gauge of the knitting machine with which it is used, so that in fine gauge machines the degree of movement permitted to the presser foot or presser feet is less than in coarser gauge machines.

Claims (6)

1. CLAIMS:1. A presser foot assembly for a flat knitting machine, comprising a support mountable on the machine for movement along the needle array, a supporting arm carried on said support, at 5 least one presser foot mounted on said supporting arm for guided displacement in relation to said supporting arm, and resilient means arranged to urge the presser foot or presser feet in a direction away from said support.

2. A presser foot assembly as claimed in claim 1, wherein 10 said presser foot is, or said presser feet are, fixed to a part slidably mounted in relation to said supporting arm and said resilient means comprise one or more springs.

3. A presser foot assembly as claimed in claim 2, wherein said slidably mounted part is located in a channel on said 15 supporting arm.

4. A presser foot assembly as claimed in claim 3, wherein said slidably mounted part is retained in said channel by a plate which covers the channel.

5. A presser foot assembly substantially as hereinbefore 2o described with reference to, and as illustrated in, the accompanying drawings.

6. A flat knitting machine including a presser foot assembly as claimed in any of the preceding claims.