GB2237035A

GB2237035A - Compound needle for knitting machines

Info

Publication number: GB2237035A
Application number: GB9021148A
Authority: GB
Inventors: Masahiro Shima
Original assignee: Shima Seiki Mfg Ltd
Current assignee: Shima Seiki Mfg Ltd
Priority date: 1989-10-03
Filing date: 1990-09-28
Publication date: 1991-04-24
Anticipated expiration: 2010-09-28
Also published as: IT1242058B; GB9021148D0; GB2237035B; IT9048327A1; JPH03119160A; JPH0466941B2; IT9048327A0; ES2026020A6; FR2652593A1

Abstract

A compound needle comprises a needle stem (2) provided with a slider groove (8) and a slider (3) slidably fitted in the slider groove of the needle stem, a cam surface (12) being formed in a portion of a guide surface in the bottom of the slider groove to be in contact with a tongue (14) of the slider, so that the tip of the tongue is raised from the groove bottom and approaches the hook (5) from within the hook as the slider is advanced. The needle may be a transfer needle with a resilient member on its side. <IMAGE>

Description

COMPOUND NEEDLE FOR KNITTING MACHINES SPECIFICATION The present invention relates to a compound needle for knitting machines.

A known compound needle comprises a needle stem and a slider slidably fitted in the needle stem, with the needle stem and the slider being operated respectively by individual cams. As shown in Figs. 4 to 6, this known compound needle 51 consists of a needle stem 52, a slider 53 slidably fitted in the needle stem 52, and a jack 54 engaging the slider 53.

A slider groove 55 formed in the needle stem 52 to receive the slider 53 has a uniform depth, and the lower edge of the slider 53 in sliding contact with the bottom surface of the slider groove 55 is straight.

Therefore, a tongue 56 of the slider 53 advances along a straight path towards the hook 57 of the needle stem 52, and hence the slider 53 must slide along a plane on the level of the hook 57 to close the hook 57 by the tongue 56 of the slider 53. Accordingly, the slider 53 must be held at a height Y (Fig.5) by the throat 58 of the needle stem 52. When such known compound needles are used in an array for knitting, a yarn 60 extending between a feeder 59 and a sinker 61 extends in a straight line and in contact with the throats 58 of the fully raised compound needles 52 as shown in Fig. 5 in side elevation.When the needle stem 52 of the compound needle 51a descends to catch the yarn 60 with its hook 57a, it is possible that the tip of the hook 57a may stick in the yarn 60 or that the hook 57 may fail to catch the yarn 60, because the yarn 60 is raised by the throat 58 of the descending adjacent compound needle 5lob, with the result that a stable knitting operation cannot be achieved.

During the knitting operation, the greater the height Y of the throat of the shank, the greater is the frictional resistance of the needle acting on the loop retained by the needle. Such a large frictional resistance may cause yarn breakage or may form irregular stitches. Such a problem may be lessened by increasing the length of a portion of the needle stem between the hook 57 and the throat 58 of a width Y, but this requires an increase in the stroke of the needle stem.

In view of the foregoing problems of the conventional compound needle, it is an object of the present invention to provide a compound needle consisting of a needle stem having a comparatively small throat width, namely, size of the throat with respect to the direction along the depth of the needle groove, and capable of applying a comparatively small frictional resistance to the old loop retained by the needle, and having a slider capable of advancing to the hook of the needle stem without sticking in the yarn fed to the hook.

In accordance with the present invention, a compound needle for knitting machines comprises a needle stem provided with a slider groove, and a slider slidably fitted in the slider groove of the needle stem, wherein a cam surface is formed. in a portion of a guide surface formed in the bottom of the slider groove to be in contact with the tongue of the slider, and the slider is raised from the bottom of the slider groove by the cam surface formed in the bottom of the slider groove as the slider advances towards the hook of the needle stem so that the tongue of the slider comes into contact with the hook of the needle stem.

In a preferred embodiment the slider slidably fitted in the needle stem is driven for advancement by a slider operating cam which engages the butt of the slider so that the tongue of the slider approaches the hook of the needle stem. The lower edge of the head portion of the slider slides along the cam surface formed in the bottom surface of the slider groove so that the tongue of the slider is raised gradually in the slider groove as the tongue of the slider approaches the hook of the needle stem. Consequently, the tongue approaches the hook of the needle stem from the side of the shank and finally closes the hook.

Thus, the tongue of the slider comes into contact with the hook without sticking in the yarn being caught by the hook. Since the needle stem has a comparatively narrow throat, a comparatively small frictional resistance acts on the old loop retained by the needle stem while the needle stem moves vertically.

In order that the invention may be more fully understood, one embodiment of needle in accordance with the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a side elevation of a preferred embodiment of compound needle according to the present invention.

Fig. 2 is a longitudinal sectional view of the head portion of the compound needle of Fig. 1; Figs. 3a, 3b, 3c and 3d are side elevations of the head portion of the compound needle of Fig. 1, showing sequential stages of movement of the slider; Fig. 4 is a side elevation of a conventional compound needle; Fig. 5 is an enlarged side elevation of the hook of the known compound needle of Fig. 4; and Fig. 6 is a front view of assistance in explaining the movement of an array of the conventional compound needles for a knitting operation.

A compound needle embodying the present invention consists of a needle stem 2, a slider 3 and a needle jack 4. The needle stem 2 has one end provided with a hook 5 and the other end engaging the needle jack 4. The needle stem 2 and the needle jack 4 may be formed as a single piece. When used as a transfer needle, the compound needle 1 is provided on its side surface with an elastic transfer piece 6. A slider groove 8 for receiving the slider 3 is formed in the upper surface of the needle stem 2 with a shape conforming to that of the slider 3. The slider groove 8 has a deep section 9 at a portion near the hook 5, and a shallow section 10 over the other portion. The deep section 9 corresponds to the throat 11 of the needle stem 2. A cam surface 12 is formed in the bottom surface of the deep section 9. The cam surface 12 is inclined upwards towards the hook 5.The width X of the throat 11 is smaller than the width Y of the throat of the conventional compound needle.

The slider 3 is provided with a tongue 14 at its front end 13. The lower edge of the front end 13 is curved in the shape of a part-circular arc to form a sliding edge 15. When the slider 3 is fitted in the slider groove 8, the sliding edge 15 rests on the bottom surface 9 of the slider groove 8. The slider 3 is provided with a slider butt 16.

As shown in Fig. 1, the rear end of the shank 17 of the slider 3 is held between fingers 18 of the needle jack 4 so as to slide within a U-shaped slot defined by the fingers 18.

When the compound needle is inserted in a needle groove, the shank 17 of the slider 3 is in the shallow section 10 of the slider groove 8 of the needle stem 2, and the front end 13 of the same is in the deep section 9 of the slider groove 8 of the needle stem 2 with the sliding edge 13 resting on the cam surface 12 in the deep section 9 of the slider groove 8 of the needle stem 2.

The slider 3 is driven for sliding movement within the slider groove 8 of the needle stem 2 by a slider operating cam (not shown) that engages the slider butt 16. In the state shown in Fig. 3a, in which the slider 3 is fully retracted to its rearmost position within the needle stem 2, the tongue 14 of the slider 3 is sunk in the deep section 9 of the slider groove 8. When the slider operating cam (not shown) engages the slider butt 16 to advance (to raise) the slider 3 towards the hook 5, the sliding edge 15 of the front end 13 of the slider 3 slides along the cam surface 12 formed in the deep section 9, so that the tongue 14 of the slider 3 is raised gradually and appears from the deep section 9 of the slider groove 8 as the slider 3 moves towards the hook 5. That is, the vertical distance, as viewed in Fig. 3a, between the tip of the tongue 14 and the front end of the cam surface 12 in the deep section 9 increases gradually as the slider 3 moves towards the hook 5 from an amount H in the state shown in Fig. 3a to H' in the state shown in Fig. 3b, to H" in the state shown in Fig. 3c, and then to H'" in the state shown in Fig. 3d. Since the tip of the tongue 14 of the slider 3 approaches the hook 5 from inside the hook 5, the tongue 14 of the slider 3 moves without sticking in the yarn being fed to the compound needle.

As is apparent from the foregoing description, the tongue of the slider of the compound needle in accordance with the present invention approaches the hook of the needle stem from inside the hook as the slider advances towards the hook, so that the yarn being fed to the hook is never caught by the tongue and hence yarn breakage and faulty stitches are prevented.

Furthermore, since the slider moves in such a manner, the width of the throat of the needle stem may be comparatively small, so that the throat applies a comparatively small frictional resistance on the old loop retained by the needle stem when the needle stem moves vertically. Consequently, the yarn is less strained, and yarn breakage and irregular stitches attributable to the stitching action of the compound needle are prevented.

Claims

CLAIMS:

1. A compound needle for knitting machines comprising a needle stem provided with a slider groove, and a slider slidably fitted in the slider groove of the needle stem, wherein a cam surface is formed in a portion of a guide surface formed in the bottom of the slider groove to be in contact with the tongue of the slider, and the slider is raised from the bottom of the slider groove by the cam surface formed in the bottom of the slider groove as the slider advances towards the hook of the needle stem so that the tongue of the slider comes into contact with the hook of the needle body.

2. A compound needle as claimed in claim 1, wherein a lower edge of a front end of said slider is curved in the shape of a part-circular arc to form a sliding edge.

3. A compound needle as claimed in claim 1 or 2, which is provided on the side surface thereof with an elastic transfer piece for use as a transfer needle.

4. A compound needle for knitting machines substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.