GB2175925A - Circular knitting machine with an improved patterning device - Google Patents

Abstract

A patterning device for a circular knitting machine comprises a rotary support 21,25,26 on which a plurality of needle drives 20 are mounted so as to be pivoted between an inoperative (upright) and an operative (horizontal) position in accordance with pattern requirements, drivers in operative position being carried by the rotating support into engagement with cam means 28,29 or 30 which imparts to the drivers and to associated feet 17a,b,c engaged thereby a knitting stroke in the longitudinal direction of the needles. The three cams means 28,29,30 are respectively configured to lift the associated drivers and needle in a clearing, tucking and backing (sic) stroke. The invention is particularly intended for a rib machine with sinkers 4 which move in counter motion to the needles. <IMAGE>

Description

SPECIFICATION Circular knitting machine with an improved patterning device The present invention relates to a circular knitting machine patterning device having particular but not exclusive application to R/L circular rib knitting machines.

A known form of circular knitting machine consists of needles which can be moved in their longitudinal direction in grooves of a needle cylinder, sinkers which project between the needles and can be moved transverse to the needles and in the latters' longitudinal direction by a sinker cam formed from like segments each belonging to a respective knitting system, so as to enable the distance required for forming a stitch to be covered partly by the needles guiding the yarn and partly by the sinkers, and an outer pattern drum per system, which can be rotated about its shaft by the needle cylinder and the surface of which is provided with grooves, whose spacing corresponds to that of the needles or an integral multiple thereof, for accommodating needle drivers which can be expelled according to the pattern by three fixed cams arranged one above the other on the outer circumference of the drum, so as to cause the latch needles which are to be moved to carry out a backing, tucking or knitting movement.

This machine can achieve high operating speeds, due to the fact that, during the loopforming process, not only do the needles execute their drawing-off movement, but the sinkers, via which the yarn is formed into loops, are also moved in the opposite direction, so that the distance required for forming a stitch is covered partly by the needles guiding the yarn and partly by the sinkers (DE-OS 33 11 361) However the disadvantage of this machine lies in the fact that it can only produce campatterned articles.Individual needle selection by means of a two- or three-way technique, as is usual in conventional right-left circular knitting machines (DE-OS 3 222 744) by swinging the needles or the needle drivers away from a single clearing cam per system, cannot be carried out by machines of the type in question, as the clearing cams, provided for knitting, tucking and backing, of the needle cam are completely different.

A pattern drum of the above-mentioned type has been proposed in order to overcome this disadvantage. However this pattern drum, which is distinguished from conventional, obli que pattern wheels (DE-OS 2 121 789) by its obvious advantages as regards space, has the disadvantage that the needle drivers have to be manually inserted in the grooves of the drum, according to the pattern, so as to en sure that they are associated with the correct cams as required by the pattern. The insertion of the needle drivers in the drum is a timeconsuming and expensive procedure, which requires the drum to be removed from the machine and the latter to be dismantled.

An object of the invention is therefore to reduce the time required for pattern changing and the costs that this entails, and to increase the productivity of the machine. More particularly, an object of the invention is to provide a machine in which the needle drivers of the patterning device can be programmed manually or by an appropriate device in the machine, yet which is of simple, space-saving construction and allows economic manufacture.

According to the invention there is provided a circular knitting machine comprising a rotary needle cylinder with a plurality of needles slidably mounted thereon to perform knitting strokes, a rotary patterning device including a plurality of needle drivers, and cam means for moving the needle drivers upon rotation of the patterning device said needle drivers being pivotably mounted for selective rotational movement between an inoperative position and an operative position for cooperating with said cam means upon rotation of the device to move the needles to perform knitting strokes.

Preferably, the needle drivers have associated therewith releasable locking means which may comprise a cover plate which is associated certain ones of the needle drivers and can be moved against a spring resistance.

The invention described above is explained in detail in the following with reference to an embodiment. In the accompanying drawings: Figure 1 is a partial section through the needle cylinder of circular knitting machine fitted with a patterning device, according to the invention, Figure 2 is a partial view of the needle cylinder cam and the drum cam and Figure 3 is a section Ill-Ill according to Figure 1.

The latch needles 1 of a circular knitting machine are mounted in grooves 2 of a needle cylinder 3 so as to be displaceable in the longitudinal direction. A sinker 4 is arranged between each two latch needles 1, engages over the needle cylinder edge 5 and is provided with a loop-forming edge 6 and a foot 7 which engages in a sinker cam 8. Each sinker 4 is mounted on a lever 9 which can be pivoted about its pivot 12 by two radially acting cams 10: 11. The sinker cam 8, which is formed from like segments 13, each assocated with a knitting system, is mounted on a fixed bearing ring 14 of the machine, each segment 13 being secured to a support 15.

Each latch needle 1 is provided with a loopforming and guide foot 16, which engages in a cam 16a, and is connected to an intermediate driver 17, which is in each case provided with three clearing feet 17a; 17b; 17c, so as to move with this intermediate driver. Each knitting system of the circular knitting machine is provided with a pattern drum 19, which can be driven by the needle cylinder 3 via a spur gear 18 and in which needle drivers 20, arranged one above the other at three levels and radially pivotable in a vertical plane, are inserted. For this purpose the needle drivers 20 are mounted in a respective sinker 21, each of which is held at the top and bottom in radial grooves 22; 23 by two disks 25; 26 which can be fixed on the shaft 24 of the drum 19.In order to prevent the sinkers 21 from falling out of the drum 19, their feet 21a; 21b are inserted in annular grooves 25a, 26a in the disks 25; 26. A small spacer plate 27 is inserted between each two sinkers 21 and simply engages at the top and bottom in the annular grooves 25a; 26a in the disks 25; 26.

The needle drivers 20 can be pivoted between an active position, in which they are approximately horizontal, and an inactive position.

In the active position the needle drivers 20 can be pivoted according to the pattern by a cam, which is associated with the needle drivers 20 of each level and which in each case consists of a lower clearing part 28a; 29a; 30a and an upper covering part 28b; 29b; 30b, and can thus influence one of the three clearing feet 17a; 17b; 17c of the intermediate needle driver 17. In the inactive position the needle drivers 20 of each level are approximately vertical and fixed in position by a cover plate 31, which is pushed onto the drum shaft 24 and can be moved against the force of a spring 32. For this purpose each cover plate 31 is provided with an annular groove 33, against the outer flange of which the ends of the needle drivers 20 come to rest in their inactive position.The stationary cam parts 28a; 28b; 29a; 29b and 30; 30b, which are provided to actuate the needle drivers 20 when in their inactive position, are all mounted by means of their bearing plates 34a; 34b; 35a; 35b and 36a; 36b on two stationary bars 37, which extend parallel to the shaft 24 of the drum 19, and are separated from one another by a respective spacer sleeve 38 which can be pushed onto the bars 34.

The method of operation of the circular knitting machine according to the invention is described in greater detail in the following: Before entering a knitting system (see arrow A in Figure 2), the needles 1 are adjusted to a uniform level by the stitch cam 16a of the preceding knitting system. This ensures that the clearing feet 17a; 17b; 1 7c of the intermediate drivers 17 are exactly above (clearing feet 17a; 17b) or below (clearing foot 17c) the needle drivers 20 which are in their active position.The needle drivers 20 are progammed such that only one of three needle drivers 20 arranged one above the other in a vertical plane is in each case in its active position, i.e. only one of three needle drivers 20 arranged at different levels one above the other in the drum 19 is active and can act on the corresponding clearing foot 17a; 1 7b or 17c of the intermediate driver 17.

If, for example, the needle driver 20 the upper level is in its active, approximately horizontal position, it is swivelled by the cam 28a; 28b associated with this level such that the corresponding latch needle 1 is raised into the latch-clearing position by the intermediate driver 17 influenced by the needle driver via the foot 17a. However, if a needle driver 20, riased by the cam 29a; 29b, of the central level acts on the clearin9 foot 17b, associated with this needle driver, of the intermediate driver 17, the relevant latch needle 1 will be raised by the latter for tucking.

Finally, if a needle driver 20 of the lower level is in its active position, it is pivoted by the cam 30a; 30b associated with this level such that the corresponding latch needle 1 is caused to carry out a backing action by the intermediate driver 17 influenced by the needle driver 20 via the foot 17c. The transmission between the needle cylinder 3 and the pattern drum 19 ensures that the needle drivers 20 are moved in synchronism with the needles 1 or the intermediate drivers 17.

Once the needles 1 have been raised by the cam parts 29a; 28b or 29a, 29b or 30a; 30b acting on the needle drivers 20, in accordance with the pattern, they are lowered by the stitch cam 16a acting on their loop-forming and guide feet 16 and simultaneously adjusted to a uniform height, so that the celaring feet 17a; 17b; 1 7c of the intermediate drivers 17 again take up the position shown in Figure 1 in relation to the needle drivers 20 in their active position and the latter can carry out a needle selection.

The movement of the sinker 4 in the needle raising direction and transverse to the latter remains the same in each knitting system irrespective of which latch needles 1 are raised in accordance with the pattern. In fact, after the loop has been cleared, the sinkers 4 at each latch clearing point are moved in a manner known per se against the drawing off movement of the associated needles 1 (by the respective segment 13 of the sinker cam) and outwards transverse to the latter (by the cam 11, which acts on the lever 9) and, after the stitch has been cast off, against the needle raising direction (again by the segment 13) and inwards transverse to the latter (by the cam 10, which also acts on the lever 9) (see Figures 1 and 2).

The pattern device according to the invention enables the needles 1 to be raised, according to the pattern, for knitting, tucking and backing, while always ensuring a direct, controlled guidance of the needles 1.

To change the pattern all that is required is to move the cover plate 31 upwards in stages against the force of the respective spring 32 and swivel the needle drivers 20 into their active or inactive position, according to the pattern. This can be carried out both manually and by means of a suitable device mounted directly on the machine in an area B of the circumference of the drum (see Figure 2).

The separation of the drum and needle cylinder drive, which is necessary in order to programme the drum, can be achieved by an appropriate cutoff coupling between the gear wheel 18 and the drum 19.

Following re-programming, the needle drivers 20 are locked in the inactive position by the cover plate 31, which rests against the corresponding disk 25 of each level under the action of the spring 32.

Claims (10)

1. A circular knitting machine comprising a rotary needle cylinder with a plurality of needles slidably mounted thereon to perform knitting strokes, a rotary patterning device including a plurality of needle drivers, and cam means for moving the needle drivers upon rotation of the patterning device said needle drivers being pivotably mounted for selective rotational movement between an inperative position and an operative position for cooperating with said cam means upon rotation of the device to move the needles selectively to perform knitting strokes.

2. A circular knitting machine according to claim 1 including first second and third of said drivers for backing tucking and knitting movement, said drivers being spaced axially along the axis of rotation of the patterning device.

3. A circular knitting machine according to claim 1 or 2 wherein the needle drivers have associated therewith releasable means to hold the drivers in said operative position.

4. A circular knitting machine according to claim 3 wherein the patterning device includes a rotary shaft on which the needle drivers are mounted, and the locking means includes a cover plate baised by spring means along the shaft towards a respective said needle driver.

5. A circular knitting machine according to any preceding claim including sinkers, and sinker cams for moving the sinkers in such a manner that stitch formation is achieved by a combined movement of the needles and sinkers relative to the needle cylinder.

6. A circular knitting machine according to any preceding claim including means for selectively moving said needle drivers between said operative and inoperative positions.

7. A circular knitting machine substantially as hereinbefore described with reference to the accompanying drawings.

8. Pattern device for circular knitting machines, in particular R/L circular rib knitting machines, comprising needles which can be moved in their longitudinal direction in the gooves of the needle cylinder, sinkers which project between the needles and can be moved transverse to the needles and in the latters' longitudinal direction by a sinker cam formed from like segments each belonging to a respective knitting system, so as to enable the distance required for forming a stitch to be covered partly by the needles guiding the yarn and partly by the sinkers, and an outer pattern drum per system, which can be rotated about its shaft by the needle cylinder and the surface of which is provided with grooves, whose spacing corresponds to that of the needles or an integral multiple thereof, for accomodating needle drivers which can be expelled according to the pattern by three fixed cams arranged one above the other on the outer circumference of the drum, so as to cause the latch needles which are to be moved to carry out a backing, tucking or knitting movement, wherein the needle drivers, the pivot of which is in the grooves of the drum, are mounted one above the other at three levels in a vertical plane so as to be pivotable in the radial direction between an active and an inactive position, and that in the active position they are in which they are approximately vertical and no longer influenced by the cams they are fixed by a releasable locking element.

9. Pattern device according to claim 8 wherein the detachable locking element consists of a cover plate which is in each case associated with the needle drivers of one level, can be moved against a spring resistance along the drum shaft and the outer flange of which fixes the drivers in their inactive position.

10. Pattern device according to claim 8 wherein the swivel bearing for the needle drivers is in each case formed in a sinker and the sinkers of one level, in the same way as small spacer plates formed between the sinkers, are held at the top and bottom in a disk which can be pushed onto the drum shaft.