GB2232689A

GB2232689A - Improved latch needle

Info

Publication number: GB2232689A
Application number: GB9012141A
Authority: GB
Inventors: Werner Nessmann; Josef Glorius
Original assignee: ESDA STRUMPFKOMBINAT VEB
Current assignee: ESDA STRUMPFKOMBINAT VEB
Priority date: 1989-06-12
Filing date: 1990-05-31
Publication date: 1990-12-19
Also published as: IT1242110B; IT9048036A0; IT9048036A1; DD284925A5; GB9012141D0; DE4012710A1

Abstract

A latch needle (1) for knitting machines has a portion (A) of uniform width in the region of the pivot axis (5) followed by a portion (C) tapering at a constant angle up to the start of spoon portion (6). Preferably, the portion (A) is half the length of the latch from the pivot and the angle of taper of portion (C) is 45 DEG . <IMAGE>

Description

IMPROVED LATCH TYPE NEEDLE DESCRIPTION This invention relates to an improved latch type needle for use with hosiery and knitting machines.

When manufacturing hosiery and knitted articles, plaiting is frequently achieved by feeding two different threads separately to the needles in such a way that, during knitting, these threads retain their position relative to one another so that one thread acts as the main thread and is visible on the wrong side of the article whereas the other thread acts as the plaiting thread and is visible on the right side of the article.

Various technical means have been used in the past to make plaiting a more reliable production process. For instance, it is known from the prior art that the thread carrier is designed so that the plaiting thread and the main thread are guided through two different openings in the thread carrier in such a manner that differentiated feeding angles are produced whereby the two threads are inserted next to or on top of one another in the open needle hooks between the needle head and the needle front.

The tension for both threads must be correctly adjusted. Thus, each thread is guided through its own thread tightener. The tension of the main thread is kept slightly tighter so that it is located firmly in the needle head and cannot shift, owing to the greater friction, in front of the plaiting thread.

Experience has shown, however, that the previously known technical means are not sufficient to guarantee the level of reliability required in production to achieve perfect plaiting.

Plaiting faults occur particularly frequently, for example, in hosiery manufactured on twin-cylinder knitting machines of right/right construction or produced as ribbed garments. Because of this alternating looping by needles in the upper and lower needle cylinders, special thread carriers are used to feed the two threads lying adjacent to one another to the needles.

During this thread feeding process, differences in the thread tension from spool to spool or within a spool and differences in the yarns between various spinning batches, dyes or dye lots already lead to frequent plaiting faults.

Another major drawback of this thread feeding process in twin-cylinder machines arises during turning of the heel and tow when, as a result of the change in the direction of rotation of the needle cylinder and particularly at high speeds, the position of the two separately fed threads does not remain constant and the familiar plaiting faults occur. An attempt to improve the guidance of both threads between the needle front and needle hook by supporting the position of the two threads up to the start of looping by means of special movements of stop rods and auxiliary stop rods is also known.

This supporting action by means of stop rods is not effective however if, e.g. for panty hose, there is a substantial difference in the required stitch size between upper leg and ankle, with the result that the altered position of the needle relative to the stop rod does not guarantee reliable and constant feeding of the two threads.

The latch type needles known from the prior art have a reducing latch shank width. This hitherto standard design of needle latch has frequently led to plaiting faults when thread feeding differences occur because the main thread can move under the plaiting thread.

The aim of the invention is to provide an improved latch type needle which is capable of reducing the number of plaiting faults thereby improving knitting quality and increasing productivity.

It is an object of the invention to provide a latch type needle of a design such that the main thread is not pushed under the plaiting thread during the knitting process.

According to the invention there is provided a latch type needle for hosiery and knitting machines, comprising a needle having a shank and a latch pivotable and about an axis and supported in the front of the needle, the needle latch having a shank including a broader portion in the region of the pivot axis which extends over a length (A), calculated from the pivot axis to a point (B), with the broadened portion having a sloped portion (C) tapering away at a specific angle (X) from point (B) up to the start of a spoon portion at the end region of the latch remote from the pivot axis.

In the preferred embodiment, the latch shank is constructed on its inner side from the bore for the pivot axis up to in front of the spoon portion of the latch with a uniform width, the broad latch shank tapering off towards the spoon portion with a slope for holding the main thread in such a way that it does not adversely affect the basic stitch-forming function of the needle latch.

On closure of the latch, a main thread is held in its fixed position by the nose-like projection on the latch shank and is thereby prevented in this needle position from being pushed under a plaiting thread.

The chamfer or slope from the broadened latch shank to the spoon portion of the latch ensures a good sliding transfer of the half-stitch over the opened latch. The slope on the latch is advantageously so selected that the angle between the slope and the latch centre line is in the region of 450.

The advantages of this latch type needle are basically that the number of plaiting faults is reduced, thereby improving knitting quality and increasing productivity.

A preferred needle of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1, is a side view of the head and front region of a latch type needle of the invention, with the needle head open and the latch fully retracted and, Figure 2, is a side view of the head and front region of the latch type needle of Figure 1 but in its closed position adjacent to the needle head.

Referring to the drawings, Figure 1 shows a part of a needle having a front region 2, a needle head 3 and a needle latch 4. The needle latch 4 is mounted to pivot about axis 5 so as to be capable of swivelling in an opening and closing movement.

The broadening of the latch shank to the same width as the latch shank in the region of the axis 5 extends over a length A which is advantageously half the latch length from the pivot axis 5 to the end latch spoon 6.

The broadened portion extends up to point B and from there on graduates, with a slope C at an angle X (preferably in the region of 450 to imaginary latch centre line 7) into the conventionally shaped spoon 6.

Figure 2, shows a part of the needle 1 with the needle latch 4 in its closed position in which the spoon 6 covers the point of the needle head 3. During the movement of the latch into this closed position and during further movement of the needle, main thread 8 is held in the required fixed position, as a result of the broadening according to the invention of the latch shank, by slope C, thereby preventing the main thread 8 from being able to move under the plaiting thread 9.

To sum up therefore, the illustrated preferred embodiment comprises a latch type needle (1) for hosiery and knitting machines having a needle shank (2) and a latch (4) pivotably supported on axis (5) in the front region (2) of the needle. The needle (1) has a broadening of the latch shank (2) to the same width as the latch shank in the region of the pivot axis (5) over a specific length (A), calculated from the pivot axis (5) to the point (B), with the broadened portion tapering away at a specific angle (X) from point (B) up to the start of spoon portion (6). Preferably, the broadened portion of the latch shank is half the distance from the pivot axis (5) to the end of the spoon (6) and slope (C) which tapers from the point (B) to the start of the spoon portion (6) is 450.

Claims

1. A latch type needle for hosiery and knitting machines, comprising a needle having a shank and a latch pivotable and about an axis and supported in the front of the needle, the needle latch having a shank including a broader portion in the region of the pivot axis which extends over a length (A), calculated from the pivot axis to a point (B), with the broadened portion having a sloped portion (C) tapering away at a specific angle (X) from point (B) up to the start of a spoon portion at the end region of the latch remote from the pivot axis.

2. A latch type needle according to claim 1, wherein the length (A) of the broadened portion of the latch shank is half the distance from the pivot axis to the end of the spoon portion.

3. A latch type needle according to claim 1, wherein the angle (X) of the sloped portion (C) is 450.

4. A latch type needle according to claim 3, wherein a main thread can be held by the sloped portion (C) of the broadened latch shank thereby preventing it from being pushed under a plaiting thread.

5. An improved latch needle substantially as herein described with reference to the accompanying drawings.