GB2061327A

GB2061327A - A needle control and selection mechanism for a knitting

Info

Publication number: GB2061327A
Application number: GB8029078A
Authority: GB
Original assignee: SCHAFFHAUSER STRICKMASCHF
Current assignee: SCHAFFHAUSER STRICKMASCHF
Priority date: 1979-09-26
Filing date: 1980-09-09
Publication date: 1981-05-13
Also published as: IT1129175B; CH649109A5; IT8068451A0; JPS6047948B2; ES8105799A1; GB2061327B; DE2938835A1; ES495320A0; JPS5653252A; DE2938835C3; DE2938835B2

Abstract

Needles 12 in a flat bed knitting machine each have a respective jack 13 having a combined selection and expulsion (or rejection) butt 21 cooperative with selection cam arrangements, each of which comprises a pair of cam parts 23a and 23b which are of substantially- identical mirror image configuration relative to one another and of which the upstream one (23a in Fig. 3) serves by its surface 25 to pivot the jacks 13 into dispositions in which ends 22 thereof are brought into the range of influence of electromagnetic selection members 17 and the downstream one (23b) serves by its face 24 to bring into operation selected jacks which are repelled by the members 17. <IMAGE>

Description

SPECIFICATION A needle control and selection mechanism for a knitting machine This invention relates to a needle control and selection mechanism for a knitting machine, more especially a flat knitting machine, having cam parts, and having electromagnetic selection members which are energisable in accordance with a desired pattern, and having needles which are mounted so as to be longitudinally displaceable in needle beds, and having needle jacks which are associated with the needles and which are mounted so as to be longitudinally displaceable and swingable and which can be applied, against the force of a restoring spring, by means of pressure cam parts, against the electromagnetic selection members.

Arrangements of this kind are known, for example, from German Offenlegungsschrift No.

1 6 35 900, German Patent No. 21 53 428 and German Offenlegungsschrift No. 1 9 52 827.

The problem underlying the invention is to design the needle control and selection mechanism for an electrically-controlled knitting machine constructionally so as to be as simple as possible without impairing its operating reliability.

In accordance with the invention, the problem posed is solved by providing a needle control and selection mechanism for a knitting machine, more especially a flat knitting machine, having cam parts, and having electromagnetic selection members which are energisable in accordance with a pattern, and having needles which are mounted so as to be longitudinally displaceable in needle beds, and having needle jacks which are associated with the needles and which are mounted so as to be longitudinally displaceable and swingable and which can be applied, against the force of a restoring spring, by means of pressure cam parts, against the electromagnetic selection members, characterised by the provision, in the selection region of the cam, of at least two selection cam parts, of mirror-image configuration, which are arranged so as to be staggered relative to one another transversely to the machine's direction of run and are countercurrently adjustable and which each have both a run-up surface, which is effective perpendicularly to the cam plane, and an expulsion surface, which is effective in the cam plane, for the needle jacks which are each provided with a combined selection and expulsion butt, and in that the electromagnetic selection members act from below or behind on ends of the needle jacks which project beyond the outer longitudinal edge of the needle beds.

In the needle control and selection mechanism of the invention, the electromagnetic selection members (which are preferably permanent magnets having cast-off coils) act on the ends of the needle jacks which project beyond the needle bed edge. In this region magnetic stray-flux formation is less than in the case of electromagnetic selection members which are located in the region of the machine bed, which favours accurate selection of the individual needles.

Because use is made of combined selection cam parts which can be employed both as pressure cam parts and expulsion cam parts, cam production is favoured. The pairs of selection cam parts, of mirror image configuration with respect to one another, co-operate with one another in such a way that, as related to flat knitting machines, the selection cam part which is to the front in the respective direction of travel of the carriage acts as a pressure cam part, whilst the following selection cam part causes expulsion of the selected needle jacks. In the other carriage movement, the function of the two selection cam parts is interchanged. Upon each carriage stroke reversal, the two selection cam parts are adjusted in opposite directions.At the selection points, in the mechanism in accordance with the invention, the needle jacks are engaged, after only very short cast-off path, assisted by the restoring spring, by the expulsion surface of a selection cam part. The expulsion surfaces of the selection cam parts, which are adjustable in opposite directions in pairs, can, in this respect, advantageously extend obliquely in the sense of an undercut formation in the direction of the cam plate, so that the appropriately obliquely extending expulsion edge of the jack butt of the needle jack is drawn at the expulsion surface completely into the jack butt path as soon as the jack butt runs up, by an edge thereof, onto the expulsion surface. This favours rapid selection and increases operational reliability.

The mechanism in accordance with the invention has the further advantage that the adjustment of the two countercurrently-adjustable selection cam parts can be checked at any time and can if necessary be re-adjusted, without the cam plate of the carriage having to be removed for that purpose. The cam plate can have, in those regions where the two countercurrentlyadjustable selection cam parts adjoin one another, viewing perforations which allow the selection points and the immediately adjoining attachment points of the expulsion surfaces of the selection cam part pairs to be visible from the reverse side of the cam plate.

The countercurrent adjustment of all of the selection cam part pairs of a cam plate, of which one has to be arranged between each consecutive knitting system pair, can in accordance with the invention be effected by means of a common adjusting slide which is movable in the direction of travel of the carriage and which is provided with switching cams. Adjusting sliders and switching dogs are advantageously arranged on the reverse side of the cam plate and co-operate with switching bodies which are connected rigidly to cam parts arranged on the front side of the cam plate and which can have stop recesses for the switching cams. The movement of the adjusting slider at the carriage reversal points can be effected by mechanical impingement of the adjusting slider ends.Advantageously, however, it is effected by means of electrical actuating members which are arranged together with other electromechanical actuating members on the carriage. The selection cam parts of the respective two-sided outer cams of the cam plate are so constructed that only one of these cam parts is arranged so as to be adjustable.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a fragmentary cross-section through the outer edge region of a needle bed of a flat (or straight bar) knitting machine and the associated portion of the cam plate, illustrating a preferred embodiment of the invention; Fig. 2 is a view comparable with Fig. 1, but in which the cross-section is taken in the cam portion at a different point from the section of Fig. 1; Fig. 3 is a plan view of the cam parts of a cam plate, together with a representation of a needle and a needle jack, being parts of the arrangements illustrated in Figs. 1 and 2; Fig. 4 is a view similar to Fig. 3, but illustrating cam part positions for a direction of travel of the carriage which is opposite as compared with Fig.

3; and Fig. 5 shows a partial plan view of the reverse side of the cam plate and its control arrangement for the selection cam parts.

The cross-sectional views of Figs. 1 and 2 show the outer edge portion of a needle bed 10 of a flat knitting machine. The section extends through a needle bed groove 11, in which are accommodated a needle 12 evident as a whole from Fig. 3 and a needle jack 13. Of the carriage which is longitudinally displaceable in known manner over the needle bed 10, only a cam plate 14 is shown, to the outer edse of which is screwed a retaining stirrup 1 5 for attachment of magnet holders 16. Only one such magnet holder 16, with one selection magnet 17, is shown. The selection magnet 17 is a permanent magnet having a cast-off coil which is energisable in accordance with the desired pattern and the poles of which project as far as into the plane of the bottom of the needle bed groove 11 directly beside the outer edge 1 8 of the needle bed 10.

Adjusting sliders, switching dogs and switching bodies shown in Fig. 5 are not shown in Figs 1 and 2 for reasons of clarity.

The needle jack 13 is designed as a swivel jack which is under the bias of a spring 19 supported against the base of the needle bed groove 11. The needle jack 13 has, at its inner end, a restoring butt 20 and in its central region a combined selection and expulsion butt 21, and forms, with its end 22 projecting beyond the outer edge 18 of the needle bed 10, an armature for the selection magnets 17. The combined selection and expulsion butt 21 of the needle jack 13 cooperates with selection cam parts 23a and 23b which are arranged in pairs and the construction of which will be explained in more detail in connection with Figs. 3 and 4.Fig. 1 shows the needle jack 1 3 directly prior to needle selection, when it is swung inwards by a selection cam part 23 against the force of the spring 19 into the needle bed 10, so that its armature end 22 is applied to a selection magnet 1 7.

Fig. 2 shows the needle jack 13 immediately after it has been selected, i.e. its armature end 22 has been knocked off, by energising of the selection magnet 17, from the selection magnet and its combined selection and expulsion butt 21 has passed into the region of influence of the expulsion surface 24 of a selection cam part 23.

Figs. 3 and 4 show part of the cam of the carriage of the machine. Here only the cam parts in the external selection region A are of interest. Of the selection magnets 17 which are similarly fastened to the carriage, two are indicated by broken lines. They are aligned at the transition point between the selection cam parts 23 which are arranged in each case, side-by-side in pairs and which are designated in Figs. 3 and 4 for differentiation by the references 23a and 23b. The selection cam parts 23a and 23b of a selection cam part pair are designed so as to be of identical but mirror image configuration and each has a run-up surface which is effective perpendicularly to the needle bed plane and to the cam plate 14 and an expulsion surface 24 which is effective in the cam plane in the needle expulsion direction.

Evident from Fig. 1 are the run-up surface 23 and its effect; Fig. 2 shows the expulsion surface 24 and its effect. Fig. 2 also shows that the expulsion surface 24 extends obliquely in the sense of an undercut formation in the direction of the cam plate 14 and that the expulsion edge of the combined selection and expulsion butt 21 of the needle jack 13 has a correspondingly obliquelyextending expulsion edge. Through this obliquity the result is achieved that the expulsion butt is attracted, or drawn up, onto the selection cam part 23 in the direction of the cam plate as soon as it passes, after casting-off of a needle jack by a selection magnet 17, into the region of influence of the selection cam part 23, which in each case follows in the direction of run-through, of a selection cam part pair.In Fig. 3, in which the selection cam parts 23 are switched for a runthrough of the needles and jacks through the cam tracks in the direction of the arrow 26, the following selection cam part is the selection cam part 23b. In the case of the cam parts switched in accordance with Fig. 4 in the direction of passage 27, it is the selection cam part 23a.

Figs. 3 and 4 reveal, for the two selection cam parts 23a and 23b of each selection cam part pair, guide slots 28 which extend transversely to the longitudinal adjustment movement of the carriage which is indicated by the arrows 38, 39. In the direction of these slots 28, the two selection cam parts 23a and 23b can be adjusted countercurrently to one another from the position evident from Fig. 3 into the position evident from Fig. 4, and vice versa, according to the direction of travel of the carriage. The adjusting mechanism will be explained hereinunder in connection with Fig. 5.As a result of the staggered arrangement of the two selection cam parts 23a and 23b and the interchanging, occurring upon each carriage reversal, of the displacement position of the two selection cam parts it is ensured that, in the region of the selection point characterised by a selection magnet 17, initially the selection cam part which is to the front in the respective direction of passage of the carriage -- that is in Fig. 3 the selection cam part 23a - becomes effective with its run-up surface 25, whilst the selection cam part 23b which follows in the direction of passage of the carriage acts with its expulsion surface 24 on the cast-off needle jacks 1 3.As a result of the staggered arrangement of the respectively following selection cam part of a selection cam part pair, the run-up surface 25 thereof cannot affect the butts 21 of the needle jacks.

Figs. 3 and 4 reveal at the actual selection point, namely at the transition point between the two selection cam parts 23a and 23b of a selection cam part pair, a passage aperture 29 in the cam plate 14. Through this passage aperture 29 the attachment position of the expulsion surfaces 24 of the selection cam parts 23 with regard to the cast-off jack butts 21 can be checked for adjustment.

Fig. 5 shows the adjusting arrangement for the selection cam part pairs 23a/23b. Each selection cam part 23a,23b is connected through the guide slots 28 of the cam plate 14 to a switching body 30a or 30b which are arranged on the reverse side of the cam plate 14. Each switching body has a lateral stop nose 31 and a detent incision or recess 32. The lateral stop nose 31 co-operates with an adjusting eccentric 33 with which a final position of the switching bodies. 30, and therewith of the associated selection cam part 23, can be adjusted. The switching bodies are forced by springs 40 shown in Fig. 5 into this one end position in which the switching body 30b is to be found in Fig. 5. The springs 40 are arranged in the slots 28.The other switching position of the switching bodies 30a and 30b is determined by switching dogs 34 or 35 which are fastened to a switching rod 37 which is adjustable in the direction of the double arrow 36 shown in Fig. 5 and which is common to all the selection cam parts of the cam plate. In their switching position the switching dogs 34 engage into the recess 32 of the switching bodies, as is the case in Fig. 5 with the switching dog 34 and the switching body 30a.

From the above, it will be understood that the position, shown in Fig. 1, of the needle jack 13 is controlled by the run-up surface 25 of the selection cam part, being moved to the front in each case in the direction of passage of the carriage, of a selection cam part pair 23. If the selection magnet 1 7 is not energised, the needle jack 13 remains held in this position until the selection and expulsion butt 21 has slid away over the adjoint-point of the expulsion surface 24 of the following selection cam part of the selection cam part pair 23a/23b. The needles then remain in the non-knitting position. With a selection magnet 1 7 energised at the selection point, the needle butt 1 3 is, on the other hand, cast-off or repelled out of the selection position evident from Fig. 1, so that its selection and expulsion butt 21 is grasped by the expulsion surface 24 of the following selection cam part of the selection cam part pair 23a/23b.

The corresponding needle 12 is then moved into the knitting or tucking or stitch-transfer position, depending on how the other cam parts, not of interest here, of the system are switched.

Claims

1. A needle control and selection mechanism for a knitting machine, more especially a flat knitting machine, having cam parts, and having electromagnetic selection members which are energisable in accordance with a pattern, and having needles which are mounted so as to be longitudinally displaceable in needle beds, and having needle jacks which are associated with the needles and which are mounted so as to be longitudinally displaceable and swingable and which can be applied, against the force of a restoring spring, by means of pressure cam parts, against the electromagnetic selection members, characterised by the provision, in the selection region of the cam, of at least two selection cam parts, of mirror-image configuration, which are arranged so as to be staggered relative to one another transversely to the machine's direction of run and are countercurrently adjustable and which each have both a run-up surface, which is effective perpendicularly to the cam plane, and an expulsion surface, which is effective in the cam plane, for the needle jacks which are each provided with a combined selection and expulsion butt, and in that the electromagnetic selection members act from below cr behind on ends of the needle jacks which project beyond the outer longitudinal edge of the needle beds.

2. A needle control and selection mechanism as claimed in claim 1, characterised in that the selection cam part which is in each case to the front in the direction of travel of the machine prepares the needle jack selection, and the selection cam part which is in each case to the rear brings about a selection which has been made.

3. A needle control and selection mechanism as claimed in claim 1 or 2, characterised in that the electromagnetic selection members are connected, by at least one stirrup engaging around the free ends of the needle jacks, to the cam plate.

4. A needle control and selection mechanism as claimed in claims 1,2 or 3, characterised in that the cam plate has viewing perforations in those regions where two countercurrently-adjustable selection cam parts border one another.

5. A needle control and selection mechanism as claimed in any preceding claim characterised in that the selection point lies between the two selection cam parts which form a pair and between two neighbouring systems and in that, in the direction of travel of the machine, the selection cam parts overlap knitting cam parts of these neighbouring systems.

6. A needle control and selection mechanism as claimed in any preceding claim characterised in that the expulsion surfaces of the selection cam parts which are countercurrently adjustable in pairs extend obliquely in the sense of an undercut formation in the direction of the cam plate and the combined selection and expulsion butt of each needle jack has an appropriately obliquely extending expulsion edge.

7. A needle control and selection mechanism as claimed in any preceding claim characterised in that the countercurrent adjustment of all of the selection cam part pairs of a cam plate is effected by means of a common adjusting rod which is movable in the direction of travel of the machine and which is provided with switching cams engageable in stop recesses of the selection cam parts or switching parts which are connected rigidly thereto, and in that the selection cam parts are under spring loading.

8. A needle control and selection mechanism as claimed in claim 7, characterised in that the adjusting rod is arranged on the reverse of the cam plate and is displaceable at the carriage reversal points by means of electrical or mechanical actuating members.

9. A needle control and selection mechanism as claimed in any preceding claim characterised in that the one position of the cam parts of a selection cam part pair is in each case determined by an adjustable stop eccentric.

10. A needle control and selection mechanism as claimed in any preceding claim characterised in that at least a part of the selection cam part pairs is associated with two neighbouring systems and in the one direction of travel of the machine influences the one system and in the other direction of travel of the machine influences the other system.

11. A needle control and selection mechanism for a knitting machine substantially as hereinbefore described with reference to the accompanying drawings.