GB2057517A - Thread guide for knitting machines - Google Patents

Abstract

In order to provide a thread guide which will accommodate knots and other thickened zones without breaking the thread an acute angled downwardly open apex 34a in a guide bar 34 is used as a guide. The apex is inclined downwardly towards the needle hooks which are to take the thread and is preferably inclined to a tangent to the path of the needles to reduce the abruptness of the change of direction of the thread as it leaves the guide. A lower bar 36 prevents the yarn from dropping out of the guide when slack. <IMAGE>

Description

SPECIFICATION Thread guide for knitting machines This invention relates to knitting machines and more particularly to thread guide arrangements for knitting machines.

It is a problem in knitting machines particularly those with a large number of knitting systems, to tuck the thread to be inserted reliably under the hook of the knitting needles. This applies particularly to knitting machines equipped with slide needles, because a slide needle has no needle latch which thrusts the newly inserted thread under the needle hook when the needle latch closes.

Attempts have been made to insert the thread into the small available zone by means of small tubular thread guides which form a conical duct, that these thread guides have not been found satisfactory because fluff accumulates in the conical dust. Aiso, knits or thickened portions in the thread lead to thread breakage. Further, threading up of the thread into such known thread guides is difficult.

It is therefore an object of the invention to provide a thread guide for knitting machines, more particularly for circular knitting machines with slide needles but capable of permitting trouble free threading up of the thread, even in knitting machines with a large number of knitting systems.

To achieve this object, the invention proposes that a thread guide be provided with a thread guide member, forming a downwardly open acute angles groove and the apex of said guide member extends downwardly towards the needle hooks of the needles which are in the forward position and terminates slightly beneath the hooks of the needles into which the thread is to be placed and which are in the forward position. To avoid thread breakage due to knots and thickened portions in the thread it would be sufficient if the thread guide were open at the bottom only in the lower front zone of the guide member but a preferred embodiment of the thread guide according to the invention is substantially entirely open on the underside to enable fluff to drop downwardly.

To prevent the thread dropping out in the downward direction it is advisable to provide a cross-web beneath the apex of the guide member at an adequate distance from guide bar apex and more particularly at a distance from the leading end of the guide member so that it does not obstruct the passage of knots and thickened portions in the thread.

In a preferred embodiment of the thread guide according to the invention a thread guide element is provided in addition to the guide member and is disposed slightly beneath the extension of the guide member apex so that the infed thread bears only on the last-mentioned thread guide element and on the leading end of the guide member apex.

Advantageously, the second thread guide element is situated upstream of the guide member and slightly below the extension of the guide member ground.

The thread guide according to the invention can be produced particularly inexpensively if the guide member is formed by a bent sheet metal stamping. If the above-mentioned cross-web is required it can be formed by a bent tongue of the bent stamping thus dispensing with the need for either manufacturing or attaching an additional component.

To avoid excessive reversal of the thread which is to be inserted and leaves the thread guide, it is advantageous to arrange the thread guide so that the guide member apex forms an acute angle with the operating direction of the needle row so that the thread acquires a component of movement in the operating direction of the needles while the said thread is still in the thread guide.

Since the thread guide according to the invention guides the thread to a position immediately beneath the hook of the knitting needle which has been driven out into the forward position, it is advantageous to couple the thread guide with the cam action which produces the needle swing operation and more particularly to couple it fixedly to the said cam action, a feature which can be achieved by connecting the thread guide support with the conventional adjustable slide of the cam action. This ensures an optimum position for the thread guides in relation to the knitting needle under whose hook the thread is to be inserted and which has been driven out into the forward position.

Further features, details and advantages of the invention are disclosed in the description hereinbelow and the accompanying drawings of a preferred embodiment of the thread guide according to the invention in conjunction with a circular knitting machine whose knitting needles are constructed as slide needles.

In the drawing: Figure 1 is an axial section through a circular knitting machine, showing however only the parts which are essential for understanding the invention; Figure 2 is a perspective view of some cylinder and disc needles of the circular knitting machine according to Figure 1, in the region of a knitting system in conjunction with a preferred embodiment of the thread guide according to the invention; and Figure 3 is a plan view of the thread guide according to Figure 2.

Figure 1 shows a needle cylinder 1 with a row of cylinder needles 12, constructed as slide needles, which are driven into the forward and backward spring position in conventional manner by means of a cylinder cam member. The vertical position of the cylinder needles 12 at the place of maximum forward swing can be selected by means of an adjusting slide 1 6 which is slidable and adjustable in the vertical direction and supports at least those cylinder cam members which are responsible for the forward swing of the cylinder needles 12. Furthermore, a row of dial needles 1 8 is provided which co-operates in conventional manner with the row cylinder needles, which are supported and are driven out and retracted in the radial direction so that no further explanation of corresponding parts of the circular knitting machine is necessary.The dial needles 1 8 are also constructed as slide needles.

According to the invention, a thread guide, referenced generally with the numeral 20, is attached to the adjustable slide 1 6 and is provided with a thread eye 22 and a guide bar member 24 which is constructed in accordance with the invention. The latter will now be explained by reference to Figures 2 and 3.

The guide bar member 24 is constructed as a bent sheet metal stamping and is provided on a support arm 30 with a roof-shaped sheet metal bracket 32 the inside of which forms a guide bar 34. A web 36, bent inwardly and whose free end advantageously extends from opening 38 in the support arm 30, is integrally formed on the bottom region of a rearward edge on one side of the sheet metal bracket 32.

According to the invention, the thread eye 22 is arranged relative to the apex 34a of the guide bar 34 so that the thread 50, which is to be inserted, extends at an acute angle to the guide bar apex 34a and bears against the guide bar surface only in the leading, bottom region of the guide bar apex.

The numeral 12' in Figure 2 refers to the particular cylinder needle which is at that time disposed at its highest position. Figures 1 and 2 clearly show that the leading end 24a of the guide bar member 24 extends into the region immediately beneath the needle hook of the fully extended cylinder needle 12' so that the cylinder needle, which continues to move in the direction of the arrow A (see Figure 2) is able to reliably grip the thread 50 by means of the needle hook in the position 12".

Since the guide bar member 24 according to the invention is open at the bottom, it is impossible for fluff to accumulate therein and since the thread 50 is able to deflect in the downward direction, it follows that neither knots nor thickened portions in the thread could lead to thread breakage.

Finally, the web 36 prevents the thread emerging from the guide bar member 24 is the thread 50 becomes slack.

Claims (10)

1. Thread guide for knitting machines, more particularly for circular knitting machines with slide needles, comprising a guide member which forms an acute angled groove that is open in the downward direction, the apex of said bar extending downwardly at an angle towards the needle hooks and terminates beneath the hooks of the needles in an outer thread receiving position.

2. Thread guide as claimed in claim 1, in which the guide member is substantially completely open on its underside.

3. Thread guide as claimed in claim 2, in which a transverse web is provided beneath the apex of the guide member.

4. Thread guide as claimed in any of the preceding claims, in which a threaded guide element is provided upstream of the guide member and is disposed slightly beneath the extended line of the guide bar apex.

5. Thread guide as claimed in any of the preceding claims, in which the guide member is formed by a moulding of approximately triangular configuration in plan view and in side view.

6. Thread guide as claimed in any of the preceding claims, in which the guide member is formed by a bent sheet metal stamping.

7. Thread guide as claimed in claims 3 and 6, in which the transverse web is formed by a bent tongue of the bent stamping.

8. Thread guide as dlaimed in any of the preceding claims, in which the guide member apex forms an acute angle with the operating direction of the needle row.

9. Thread guide as claimed in any of the preceding claims, in which the guide member is fixedly connected to a cam member which produces the forward swinging movement of the needles.

10. A thread guide arrangement for a knitting machine substantially as hereinbefore described with reference to the accompanying drawings.