GB2170827A - A knitting machine - Google Patents

Abstract

A rib circular knitting machine has sinkers 4 which extend between the needles 1 and which are movable both longitudinally and transversely of the needles such that the distance required for the formation of a stitch is covered partly by the needles and partly by the sinkers. The needles 1 are moved by cams 14a, b, c, d for floating, tucking and knitting. The sinkers 4 are moved by sinker cams 8. In order to provide a central quality adjustment system, one common first mounting 21 is provided at each feed for at least the descending zones of the needle cams which are intended for tucking and/or knitting while a separate second mounting rigidly connected to the sinker cams is provided for the needle cams which are intended for the floating, all the first mountings 21 being movable collectively axially to the needle cylinder, in relation to the sinker cams and/or vice versa. The mountings 21 engage an annular groove 25 in a ring 23 adjustable in height by means of a screw thread 22 and a pinion 29. <IMAGE>

Description

SPECIFICATION A knitting machine This invention relates to a knitting machine and has particular application to a circular knitting machine, for example right/left circular knitting machine.

A known type of circular knitting machine includes a needle cylinder with a plurality of longitudinally displaceable needles thereon, the needles being reciprocated longitudinally by needle cams upon rotation of the cylinder. Sinkers are disposed between the needles, the sinkers being moved by sinker cams. The sinkers not only perform their customary transverse movement for detaching stitches from the needles but additionally move longitudinally of the needles so that stitching strokes for the needles are made up of the combined longitudinal movements of the needles and the sinkers. The combined longitudinal movement of the needles and sinkers produces a high operational speed. Examples of such knitting machines are disclosed in DDR unexamined Patent Specification Nos. 2408924; 3108041 and 3246512.

To enable the stitch length to be regulated the sinker cams in this type of machine can be raised and lowered individually. These machines do not allow of a time-saving central strength adjustment, such as effected in conventional right/left circular knitting machines by raising or lowering the needle cylinder, because both the needles and the sinkers are mounted in the needle cylinder.

In order to surmount this drawback and provide a central strength adjustment system it has been proposed that the needle cams and the sinker cams be given a special shape and the required stitch length be adjusted by producing a relative angular displacement of the needle cams and the sinker cams about the axis of the needle cylinder (see DDR Patent Application WP DO 4B/262 383/4).

This does produce a central strength adjustment system but the stitch formation may be disadvantageously effected due to an effective change in the movement of the needles and sinkers, leading to strain on the stitches formed, prevention of an event stitch pattern and thus production of fabrics of inferior quality.

With a view to overcoming these disadvantages the present invention provides a knitting machine comprising a plurality of longitudinally displacea ble needles, a plurality of needle cams for moving the needles longitudinally, a plurality of sinkers movable longitudinally relative to the needles whereby the combined movement of the needles and the sinkers performs stitching strokes, a plural ity of sinker cams for moving the sinkers, and means for moving the sinkers, and means for mov ing collectively the needle cams and/or the sinker cams longitudinally of the needles such as to adjust the length of the stitching strokes.

In a preferred embodiment the present invention provides a multi-system circular knitting machine for example a right/left rib circular knitting ma chine, with needles displaceable in their longitudinal direction in grooves of the needle cylinder by means of a needle cams sinkers extending between the needles and being movable transversely of the needles and also in the longitudinal direction of the latter by means of a sinker cam made of identical parts and, so arranged that the distance required for the formation of a stitch is covered partly by the thread-carrying needles and that the remaining part of the said distance is travelled by the sinker, the needle cams being arranged in groups serving for floating, tucking and/or knitting parts of the needle cam which are intended for floating taking substantially the same form as the parts of the sinker cam characterized in that each group has a common first mounting for at least the descending zones of those cams which are intended for tucking and/or knitting and a separate second mounting rigidly connected to the sinker cam for the needle cams which are intended for floating, all the first mountings for those needle cams which are intended for tucking and/or knitting being movable as a unit axially to the needle cylinder, in relation to the sinker cams and/or vice versa.

Preferably the sinker cams and the second mountings are made integral with the machine frame and all the first mountings are connected with a ring adjustable by means of a screw threading.

Preferably the first and the second mountings take the form of bars positioned vertically, there being one segment associated with each two bars, of which the bar forming the first mounting is laterally guided in the segment and the bar forming the second receiver is rigidly connected to the segement. The bars forming the first mountings may be each provided with a horizontal pin which engages a peripheral goove of the ring adjustable by means of the screw threading.

Preferably the sinker cams are mounted on one common supporting ring of the machine.

The present invention will be explained hereinafter in greater detail by way of example with reference to the accompanying drawings wherein Figure 1 is a partial cross section through the needle cylinder of a circular knitting machine in accordance with the invention.

Figure 2 is view of needle and sinker cams of the knitting machine, Figure 3 is a section along the line Ill-Ill of Figure 2, Figure 4 is a section along the line IV-IV of Figure 2, and Figure 5 is a view similar to Figure 2 of a variant of the knitting machine.

Needles 1 of the circular knitting machine are mounted in a longitudinally displaceable manner in grooves 2 of a needle cylinder 3. Between each two needles 1 is a sinker 4 which extends over the edge 5 of the needle cylinder and which is provided with a looping edge 6, and also with a foot 7 which engages a sinker cam 8. Each sinker 4 is mounted on a lever 9, pivotable about its fulcrum 12 by means of two radially acting cams 10,11.

Each needle 1 has a foot 13 which engages a respective, cam channel 14 of a 4-stage needle cam.

There are four different types of needle 1 present in the cylinder 3, their respective feet 13 a, 13 b, 13 c and 13 d being positioned at different heights on the needle shaft 15. There are thus cams with respective different shaped channels 14a, 14b, 14c and 14d, for each respective type of needle.

The needle cam channels 14a, 14b, 14c, 14d are thus formed in a group of different cams 16, 17, 18 which are for floating, tucking and knitting respectively (Figure 1 & 2).

In addition, each needle 1 is equipped with a second foot 19, to which can be allocated a fifth cam channel 20 if all the needles are to produce the same pattern. If this is the case, the cams 16, 17, 18 are omitted (see Figure 2 and 5, left-hand system).

An adjustable mounting in the form of a bar 21 is provided for moving collectively the cams for tucking and knitting (17,18). In order to obtain a central strength adjustment system all the bars 21 are connected with a ring 23, adjustable longitudinally of the needles 1 by means of a screw thread 22 (in a manner to be described in more detail hereinafter). The connection is achieved by means of a pin 24 provided at the lower end of each bar 21, which engages a continuous annular goove 25 provided in the ring 23. Each cam group is provided, for the purpose of guiding the bars 21, with a segment 26, to which a further bar 27 is securely screwed, to receive those parts 16 of the needle lock which are intended for floating. The segments 26 are mounted on the supporting ring 28 of the machine, this ring being integral with the frame of the knitting machine (not shown).

To adjust the ring 23, a pinion 29 on a shaft 30 received in the support ring 28, engages a toothed rim 31 of the ring 23. The upper end of the shaft 30 has a hexagonal profile 32, so that by rotation of the shaft 30, the longitudinal position of the cam groups is adjusted collectively.

The sinker cams 8, made up of identically similar parts 33 and each belonging to one particular cam group is mounted on a further supporting ring 34 of the machine, this ring being integral with the frame, each part 33 being affixed to a support 35 (Figure 1).

The method of operation of the circular knitting machine will be briefly explained below: On entering a cam group (see arrow A in Figure 2 and 5) the needles 1 are moved longitudinally according to the arrangement of the feet 13 a, 13 b, 13 c, 13 d, and the different cams 16, 17 or 18. The movement of the sinkers 4 both in the longitudinal needle direction and transversely thereto remains the same for each cam group. The combination of the longitudinal movement of the needles and that of the sinkers 4 produces a stitching stroke.The sinkers 4, for each stitching stroke are moved after a clearing action in opposition to the detachment movement of the associated needles 1, by the relevant parts 33 of the sinker cam 8, and also outwards and transversely of the said needles by the cam 11 which acts on the lever 9 and, after the knocking-over of the stitch, in opposition to the needle expulsion movement again by the relevant part 33, as well as inwards and transversely of the said movement by the cam 10 that acts on the lever 9 (Figures 1 and 2).

All that is necessary for regulating the length of the stitch is to turn the shaft 30 in one direction or the other with a ring spanner, placed on the hexagonal section 32. The pinion 23 engaging the toothed rim 31 is thus turned and the ring 31 thereby raised or lowered. The raising or lowering of the ring 23 is transmitted via the pin 24 to the bars 21, as a result of which the cams 17 and 18 of each cam group, which are intended for tucking knitting, are adjusted axially to the needle cylinder 3, with respect to the sinker cam 8 integral with the frame, and the cams 16 which are likewise integral with the frame and serve for floating. If the ring 31 is raised, smaller stitches are obtained as the looping depth is reduced, whereas if the ring is lowered the stitch length is increased.

As an alternative to the example shown a central strength adjustment system can also be achieved if the sinker cams and the needle cams which are intended for floating are positioned on one common support, adjustable axially in respect of the needle cylinder and the needle cams which serve for tucking and knitting are fixed in position on the frame.

It would also be conceivable, without departing from the scope of the present invention, for only the descending zones of the parts of the needle cams which serve for tucking and knitting to be adjusted axially of the needle cylinder and relative to the sinker cams and the needle cams which serve for floating. In this case, as shown in Figure 5, only the descending zones 17a, 18a, of the needle cams which serve for tucking, and knitting, respectively are positioned on the adjustable bar 21, and those parts 16 of the needle cam which serve for floating and those ascending zones 17b, 18b of the needle cams serving for tucking and knitting which expel the needles 1, are mounted on the bar 27 integral with the frame.

Claims (14)

1. A knitting machine comprising a plurality of longitudinally displaceable needles, a plurality of needle cams for moving the needles longitudinally, a plurality of sinkers movable longitudinally relative to the needles whereby the combined movement of the needles and the sinkers performs stitching strokes, a plurality of sinker cams for moving the sinkers, and means for moving collectively the needle cams and/or the sinker cams longitudinally of the needles such as to adjust the length of the stitching strokes.

2. A knitting machine according to claim 1 wherein said plurality of needles are of different types for performing different strokes, and said needle cams are arranged in groups on common mountings, the needle cams in the groups being different types for respectively operating said different needle types.

3. A knitting machine according to claim 3 wherein said collective moving means comprises a member interconnected with said mountings and means for adjusting the position of said member in a direction longitudinally of the needles.

4. A knitting machine according to claim 2 or 3 wherein said moving means is arranged to adjust only the longitudinal position of the needle cams for operating some but not all of said needle types.

5. A knitting machine according to claim 4 wherein said needle cams are for floating, tucking and knitting, and said moving means adjusts the position of only the tucking and/or knitting cams.

6. A knitting machine according to claim 5 wherein are arranged in a parallel cylindrical configuration and the knitting and/or tucking needle cams are mounted on bars extending parallel to the needles, the bars being connected to a rotatable adjustment ring threadingly engaged in a frame such that rotational adjustment of the ring adjusts the positions of the knitting and tucking needle cams longitudinally of the needles.

7. A knitting machine according to claim 6 wherein the floating needle cams are mounted on further bars parallel to the needles but which are not adjustable longitudinally of the needles.

8. A knitting machine according to claim 6 wherein said bars are connected by pins into a common annular groove formed in said ring.

9. A knitting machine according to claim 6 or 8 including a peripheral rack on said ring, and a pinion meshing with the rack to adjust the rotary position of the ring.

10. A knitting machine according to any preceding claim wherein the needle cams are arranged to produce a reciprocal needle motion comprising sequential opposed movements and said moving means is arranged to adjust only portions of the cams for producing one of said opposed movements.

11. A knitting machine according to claim 4 wherein the needle cams are for floating, tucking and knitting, and the moving means is arranged to adjust the position of only the sinker cams and the needle cams for floating.

12. A multi-system circular knitting machine for example a right/left rib circular knitting machine, with needles displaceable in their longitudinal direction in grooves of the needle cylinder by means of a needle cam, sinkers extending between the needles and being movable transversely of the needles and also in the longitudinal direction of the latter by means of sinker cams made of identical parts and so arranged that the distance required for the formation of a stitch is covered partly by the thread-carrying needles and that the remaining part of the said distance is travelled by the sinkers, the needle cams being arranged in groups serving the floating, tucking and/or knitting, parts of the needle cam which are intended for floating taking substantially the same form as the parts of the sinker cam characterized ion that each group has a common first mounting for at least the descending zones of those cams which are intended for tucking and/or knitting and a separate second mounting rigidly connected to the sinker cam for the needle cams which are intended for floating, all the first mountings for those needle cams which are intended for tucking and/or knitting being movable as a unit axially to the needle cylinder, in relation to the sinker cam and/or vice versa.

13. A circular knitting machine substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

14. A circular knitting machine substantially as hereinbefore described with reference to Figure 5 of the accompanying drawings.