GB2043714A - Compound needle for knitting machines - Google Patents

Abstract

A compound needle for a knitting machine has a hook member (10) with a hook (106), and a slider member (20) having one end portion (204) to close the hook (106). Below the hook (106), the hook member has a recess (110) to receive the end portion (204) when the hook is opened by relative lifting of the hook member (10). The hook member has a recess (112) to receive a tongue (210) on the slider member and the cooperating upper edges (112b and 210b) of these cam the end portion (204) outwardly as the hook member (10) retracts relative to the slider member (20). This movement also carries a loop out of the hook (106) to be cast off over the hook (106). <IMAGE>

Description

SPECIFICATION Compound needle for knitting machines The invention relates to a compound needle for knitting machines, in particular circular knitting machines, having a hook member and a hookclosing slider member, wherein the hook member below its hook comprises a slot extending parallel to the needle guide surfaces of the knitting machine, for receiving the upper end region of the slider member, and the hook member and the slider member are provided with co-operating slide edges for displacing the upper end region of the slider member out of the slot during the lowering of the hook member relatively to the slider member.

In a known compound needle of this kind (German Patent Specification 292226) in which the slider member is arranged on the side of the hook member remote from the hook, the hook member has below the hook a slot which extends between the two longitudinal edges of the hook member and through which engages an obliquely upwardly and outwardly extending tip of the upper end region of the slider member.The longitudinal edge facing the hook and extending obliquely upwardly and outwardly, of the upper end region of the slider member as well as the upper limiting edge extending likewise obliquely upwardly and outwardly, of the slot of the hook member form the co-operating slide edges which effect that when they are abutting each other and the hook member is being lowered relatively to the slider member, the upper tip of the slider member issues from the hook member on the side facing the hook and together with the hook encloses the thread freshly inserted into the compound needle.In the region above and below the slide edge of the hook member the latter is enlarged on its side facing the hook, so that during the displacement of the hook member the loop-forming portion of the thread must slide onto the slope produced thereby, is extended thereby and consequently highly stressed at high knitting speeds; this may go so far that welding occurs in the thread, since strong friction occurs when the loop-forming portion slides onto the so-called needle front, as a consequence of the elongation of the said portion. In consequence of the elongation of the loop-forming portion when it slides onto the needle front and the resistance produced by friction, the loop-forming portion of the thread is additionally driven in the directtion of the needle movement.This may have the consequence that the loop-forming portion does not travel under the tip of the slider member and consequently is not cast off over the needle hook during the retraction move mentofthe needle. However, the known compound needle has still further serious disadvantages. In the longitudinal direction of the needle, the slot in the hook member has a substantially larger extent than the upper end region of the slider member engaging into this slot; since the slider member is carried over the edge of this slot in the driving out and withdrawal direction, the hook member must be displaced relatively far out, in order that the loopforming portion of the thread sliding onto the needle front travels under the upper end of the tip of the slider member.Therefore the known construction necessitates a long needle stroke; this has a disadvantageous effect in respect of the knitting speed attainable, and moreover the friction problems between needle and loop-forming thread portion are further aggravated thereby. Finally only relatively long loops can be knitted by means of the known compound needle, since the slider member is arranged below or within, respectively, the hook member, whereby the loop length is increased by the width of the slider member.

An object of the invention is to provide a compound needle which permits higher knitting speeds owing to decreased friction stress of the thread to be knitted.

According to the invention the longitudinal edge of the hook member facing the free end of the hook extends approximately parallel to the displacement direction of the hook member at least to slightly below the upper end of the slider member when this assumes its lower end position in relation to the hook member and the slider member is provided with a butt or a transversely bent portion for retaining the slider member during a portion of the withdrawal movement of the hook member. It is known that a deceleration of the respective needle portion between the walls guiding the needle, e.g. of a needle cylinder, can be obtained by means of a transversely bent or domed portion extending across the needle plane.

Since the hook member below the hook does not have at least initially a rising edge, the loop-forming portion of the thread held by the hook member during the outward drive is not elongated, so that for this reason alone the stressing of the thread is far less than with the known compound needle. Since, furthermore, the slider member can be retained in its upper end position when the casting off movement of the hook member starts, the compound needle according to the invention can be operated with a much smaller needle stroke than in the prior art, and since the compound needle according to the invention can be constructed without difficulty in such a manner that the slide edges for outward displacement of the upper end region of the slider member become effective even at the start of the withdrawal movement of the hook member, for this reason, too, a part of the relative movement between the loopforming portion and the known compound needle is omitted. In the construction according to the invention, the loop to be cast off is lifted by the upper region of the slider member without friction transversely to the longitudinal direction of the needle and is then thrown off over the downwardly moving hook member. Finally, in the compound needle according to the invention, the slider member may be located without difficulty on the side of the hook of the hook member, so that shorter loops can be produced by the compound needle according to the invention than by the known construction discussed above.

In a preferred constructional form of the compound needle according to the invention the slider member below its upper end region comprises an inwardly directed tongue and the hook member comprises a correspondingly shaped cut-out, wherein limiting edges of the tongue and the cut-out facing the hook form the obliquely outwardly and upwardly extending slide edges. In this wcly a far better stability of the compound needle is obtained than in the known construction described above.

Furthermore, limiting edges of the tongue and the cut-out which face away from the hook and extend likewise upwardly and outwardly may be utilised with advantage for guiding the slider member back again against the hook member upon outward displacement of the latter.

Further features, advantages and details of the invention are clear from the accompanying claims andlorfrom the following description of a preferred constructional form of the compound needle according to the invention and the cam path for the control of this compound needle. Reference should now be made to the accompanying drawings, in which: Figure lisa side view of the compound needle; Figure 1a is a side view of the upper end of the hook member of the compound needle on a larger scale than in Figure 1; Figures 2 to 5 show the compound needle in various positions during the loop forming process; Figure 6 is a section on the line 6-6 in Figure 2 of the compound needle; and Figure 7 is a view of the cam paths for controlling the compound needle considered from the needle.

The compound needle illustrated in Figure 1 consists of a hook member 10 and a slider member 20 each of which has a butt 102 and 202, respectively. It is particularly advantageous when the hook member comprises a shank of rectangular zig-zag configuration, such as illustrated at 104; by this construction of a region located between the head of the needle and the butt of the hook member, head fractures due to injurious longitudinal oscillations are avoided.

The hook member has a hook 106 which faces away from the needle bed and which is supported by a shank region 108 which has an edge 108a facing outwardly and which extends at least approximately in the longitudinal direction of the needle. The rise angle a indicated in Figure la amounts to at most 15". Below the shank region 108, the hook member 10 comprises a central recess in the form of a pocket or a slot 110 which is bounded by an edge 11 ova which, considered from the slider member 20, is of concave configuration, namely preferably in the manner of a circular arc.

It is of particular advantage that the hook member 10 below the slot 110 comprises a cut-out 112 which is bounded at the bottom by a driver edge 11 2a and at the top by a slide edge 11 2b and comprises preferably a stepped bottom.

A further cut-out 114 which according to the invention is bounded at the top by a driver edge 1 14a is located therebelow.

The upper end region of the slider member 20 is cranked in the direction of the hook member 10, that is to say first in the direction of the shank of the hook member and then angled again in the direction of the hook 106. Furthermore the upper end region of the slider member 20 is constructed in the form of a curved tip 204 which is convex in the direction of the hook member 10 and for the upper end of which the hook 106 advantageously has a small slot 106a into which the tip 204 can engage. In the same manner as the slot 110, the slot 106a is formed centrally in the hook member 10. As has been indicated by the line 206, the slider member 20 is of reduced thickness in the region of the tip 204 than below this tip where the thickness of the slider member 20 corresponds at least approximately to that of the hook member 10.

In contrast, the thickness in the region of the tip 204 is adjusted to the width of the slots 1 06a and 110, so that the tip can engage into these slots or can be received by the slot 110, respectively. It is further noteworthy that an edge 204a of the tip 204 facing the hook member 10 has the same configuration as the edge 1 10a of the slot 110 of the hook member, and that the outer edge facing away from the hook member 10, of the tip 204 of the slider member is rectilinear and extends in the longitudinal direction of the needle.

Below the tip 204, the slider member 20 is provided with a tongue 210 which according to the invention corresponds to the shape of the cut-out 112 of the hook member 10 and at the bottom comprises a driver edge 21 0a and at the top comprises a slide edge 21 Ob . The preferred constructional form of the slider member comprises in the region of the butt 202 as well as thereabove a projection 214 which is bounded at the top by a driver edge 214a. In place of the butt 202, a sharply bent-away part of the lower end of the slider member 20 may protrude from the plane of the drawing.

As may be seen from Figure 6, in which the needle bed is to be formed by the periphery of the needle cylinder 30 of a circular knitting machine and by ledges 32 inserted into same, the compound needle according to the invention is so dimensioned that the tongue 210 of the slider member 20 projects far into the needle tricks 34 formed between the ledges 32, whereby the compound needle receives particularly good stability.

Figure 7 illustrates a view of the so-called cam surface of a circular knitting machine for the employment of the compound needle according to the invention, namely considered from the needles, and the cam tracks 44, 46 formed by the guide edges 36, 38, 40, 42 are provided for receiving the needle butts 102,202.

Because of the configuration according to the invention of the cam tracks as well as the driver edges and the slide edges of the compound needle, the following functioning of the compound needle is obtained, which is to be described with reference to Figures 2 - 5 (the numerals 2,3,4 and 5 given in brackets in Figure 7 indicate those locations of the cam tracks at which the parts of the compound needle assume the positions illustrated in the Figures with the same number). There remains to be added hereto that the Figure 3 illustrated the hook member 10 broken away at the location of the slots 110 and 106a.

The two members 10 and 20 of the compound needle are illustrated in Figure 2 in the respective lowest position in which the hook 106 and the tip 204 enclose the respective lastformed loop-forming portions 50 of a knitted hose 52. As indicated by the arrow in the hook member 10 in Figure 2, there begins then the upward displacement of the hook member, while the slider member 20 is still retained by its butt 202 in a horizontally extending region of the cam track 46, until the driver edge 1 12a of the hook member is placed against the driver edge 210a of the slider member, such as illustrated in Figure 3.

In the course of this first part of the outward displacement of the hook member 10 the tongue 210 of the slider member slides into the cut-out 112 of the hook member and the tip 204 slides into the slot 110.

Thereafter the two parts together are displaced furthertowards the top, as indicated by the two arrows in Figure 3, namely so far that the hook member and the siider member 10 and 20, respectively, assume the positions illustrated in Figure 4.

During this part of the displacement movement the loop-forming portion 50 of the thread slides downwards along the edge 108a of the hook member 10 and thereby passes by the upper end of the tip 204 of the slider member 20, the said end being completely received by the slot 110. At the same time a fresh thread 54 is inserted into the hook 106.

When the hook member 10 is drawn off downwardly by means of its butt 102 in the cam track 44, as indicated by the arrow in Figure 4, while a horizontally extending region of the cam track 46 retains the butt 202 of the slider member and thereby fixed the vertical position thereof, the upper region of the slider member 20 is swung outwards in a radial direction in consequence of the edges 102b and 21 or, whereby the old loop-forming portion 50 is drawn outwards without sliding friction. In this swing movement the upper regions of the inner edge 204a of the tip 204 and the edge 11 Oa of the slot 110 provide an assisting effect. The situation attained thereby is illustrated in Figure 5 which makes also clear that the fresh thread 54 has then be enclosed by the hook 106 and the tip 204.When the two needle members are drawn off further in a downward direction, as this is to be indicated by the two arrows in Figure 5-such drawing-off movement may be effected either alone by the butt 102 of the hook member and the two driver edges 114a and 214a, or by the two butts 102 and 202 as well as appropriately shaped regions of the cam track 44 and 46-the loop portion 50 of the old loop is cast off over the head of the hook 106 and a new loopforming portion is formed by the fresh thread 54.

The sequence of the positions according to Figures 2 et seq. is then repeated.

Furthermore, dial needles 60 have been indicated in Figure 4 by dash-dotted lines; these may likewise be constructed in the form of compound needles according to the invention.

Finally, for reasons of safety, attention is additionally directed to the fact that the cam tracks in Figure 7 are traversed by the needles from the left to the right - in machines with a stationary needle bed and moving cams the cams illustrated in Figure 7 would travel from the right to the left.

Thus the invention has provided a compound needle which is characterised above all by the fact that the respective old loop slides upon the tip of the slider member after a short needle displacement, without being forced over obliquely downwardly and outwardly rising portions of the hook member.

The tip of the slider member is received thereby completely by the hook member and it lifts the loop thereafter transversely to the needle displacement direction, whereby without sliding friction the same result is obtained as if the hook member were to possess an obliquely downwardly and outwardly rising edge. Moreover the compound needle according to the invention possesses great stability, since the hook member is located under or within, respectively, the slider member and the tongue of the latter engages deeply between the ledges 32.

The compound needle according to the invention is suitable for all loop-forming machines, i.e. therefore for circular knitting machines and flat bed knitting machines, for warp knitting machines and Raschel knitting machines, and so forth.

Claims (7)

1. Compound needle for knitting machines having a hook member and a hook-closing slider member, wherein the hook member has below its hook a slot for receiving an upper end region of the slider member and furthermore the hook member and the slider member are provided with cooperating obliquely outwardly and upwardly directed slide edges for displacing the upper end region of the slide member out of the slot during lowering of the hook member relative to the slider member, wherein the longitudinal edge of the hook member facing the free end of the hook, from the hook to at least slightly below the upper end of the slider member when this assumes its lowermost position in relation to the hook member, extends approximately parallel to the displacement direction of the hook member, and wherein the slider member is provided with means for retaining the slider member during a portion of the retraction movement of the hook member, characterized in that the slot is constructed in the form of a pocket which receives the upper end region of the slider member, that the slider member below its upper end region comprises an inwardly directed tongue and the hook member comprises a correspondingly shaped cutout, that boundary edges facing the hook, of the tongue and the cut-out form the slide edges, and that the slide edges as well as the outer longitudinal edge of the upper end region of the slider member are so constructed that during displacement of the latter out of the slot the loop to be cast off can be lifted by the upper end region of the slider member without substantial movement relatively to the latter trans verselytothe longitudinal direction of the needle as far as the outer edge of the hook.

2. Compound needle as claimed in claim 1, characterised in that the slider member is cranked at the top in the direction of the hook member

3. Compound needle as claimed in claim 1 or 2, characterised in that the outer edge remote from the hook member of the tip of the slider member is approximately rectilinear and extends in the lon gitudinal direction of the needle.

4. Compound needle as claimed in any of claims 1 to 2 characterised in that the slot is bounded in the direction of the hook by an edge which extends obliquely upwardly and outwardly, and the upper end region of the slider member comprises a correspondingly inclined edge on its side facing the hook member and is constructed in the form of a tip shaped in such a mannerthatthe latter is received completely by the slot when the slider member assumes its lower end position relatively to the hook member.

5. Compound needle as claimed in any of claims 1 to 4 characterised in that boundry edges of the tongue and the cut-out which are facing away from the hook and extend obliquely outwardly and upwardly from effective return guide edges for the slider member when the hook member is driven out relatively to the slider member.

6. Compound needles as claimed in any one of the preceding claims, characterised in that the longitudinal edge of the hook member facing the slider member forms a rise angle a of less than 15 to the displacement direction below the hook.

7. A compound needle substantially as herein before described with reference to the accompanying drawings.