GB2179964A - Circular knitting machine - Google Patents

Abstract

A circular knitting machine has needles 1 mounted for longitudinal movement on a needle cylinder 3 under the control of needle cams 16, 18. Sinkers 4 are pivotally mounted on sinker drivers 7 that are moved longitudinally of the needles 1 by sinker driver cams 10. The sinkers 4 are pivoted radially inwardly and outwardly of the cylinder 3 by cam control surfaces 8, 9 that are radially adjustable by rotation of a thumbscrew 28 which operates adjustment cams 23, 24. The knitting machine has particular application to producing single yarn backing fabrics for which large sinker movements may be needed. <IMAGE>

Description

SPECIFICATION Circular knitting machine The invention reUatesto a cí rcu la krriiring: ma chine and has pa rticularb-ut rrot excl usive aporbationto a R/L circular rib knitting machine for producing single yarn backing fabrics.

Aknown circular knitting machine for producing single yarn backing fabrics consists of needles mov able in their longitudinal direction in grooves of a needle cylinder by a needle cam, and holding-down and knockoversinkerswhich are arranged between the needles, for movement in the longitudinal direc tion ofthe needles andtransversetothe latter. The sinkers each comprise a pivotally mounted, two armed lever. Two sinker cam control surfacesacton the lever arms, one ofthe sinker cam control surfaces moving the head ofthe holding-down and knockover sinker radially ofthe cylinder in one direction and the other moving it radially in the opposite direction. Each sinker is mounted so asto swivel about a horizontal swivel axis at an associated pivot point on the needle cylinder.In order to enable the sinkers to be moved in the longitudinal direction of the needles, they are provided in the area of their swivel bearing point with a foot which engages in a sinker cam groove su rrounding the needle cylinder (DE-OS 3246 512; DE-OS 3330530).

As the foot carries out the same radial swivelling movement as the holding-down and knockover sink ers, a forced guidance ofthis foot, which would prevent wear and permit a smooth sinker movement, cannot be implemented, asthesinkercam groove must havethe necessary clearance to enablethe sinker, or its foot, to swivel in the cam groove.

Furthermore, the necessary clearance has a disadvan tageous effect on the quality of thefinished article, particularly as regards the possibility of obtaining a uniform mesh structure.

When certain articles are produced, for example single yarn backing fabrics, which require the holdingdown and knockoversinkersto cover a relatively long distance, it is not possible to control the sinker movement in a reliable manner in the case of circular knitting machines according to the prior art.

An object ofthe invention is therefore to ensure that the produced articles will be of uniform quality, irrespective of the distance to be covered by the holding-down and knockover sinkers when swivelling in the radial direction, so as to broaden the field of use of the circular knitting machine and prevent excessive wear of the sinkers or cam parts.

Another object of the invention is to develop a circular knitting machine that allows precise control of boththeswivelling movement ofthe holding-down and knockover sinkers in a direction radially of the needle cylinder and the movement ofthe holdingdown and knockoversinkers in the longitudinal direction ofthe needles, irrespective ofthe extent of each movement and independently of one another.

According to the invention there is provided a circular knitting machine comprising a rotary needle cylinder,apiuralityofneedles mountedforlongitu- dinal movement on the cylinder, a plurality of sinkers for cooperating with the needles to perform knitting strokEesrthesirgkers being pivotally mounted on sinker driversr,nou!nted'formovementlongitudinallyofthe needles, sinker cam means for pivotally moving the sinkers radially inwardly or outwardly ofthe cylinder upon rotation thereof, and sinker driver cam means for moving the sinker drivers longitudinally ofthe needles upon rotation of the cylinder.

Preferably the sinkers each include a pivotal connection to a said sinker driver, and first and second lever arms extending from said pivotal connection, and said sinker cam means includes first and second sinker cam control surfaces forcammingly engaging said lever arms respectively.

Preferably, the control surfaces can be moved partially inthe radial direction so asto adjustthe loop length of a laid-in-yarn, and the two sinker cam control surfacescan be adjusted in the radial direction and in opposite directions to one another by a common adjusting element provided for each knitting system.

Preferably, the mobile parts ofthe sinker cam control surfaces are provided on slides which can be moved against spring resistance by a respective cam, the common adjusting element representing a shaft connecting the two cams.

Preferably, also the sinker driver cam can also be adjusted in the longitudinal direction ofthe needles.

The invention will now be explained in detail in the following with reference to an embodiment. In the accompanying drawings: Figure 1 is a partial section 1-1 through the needle cylinder of a circular knitting machine according to the invention, and Figure 2 is a partial development ofthe needle- and sinker cam.

Latch needles 1 of the circular knitting machine according to the invention are mounted so as to be moveable in the longitudinal direction in the grooves 2 ofthe needle cylinder 3. Asinker4 is in each case arranged between two latch needles 1, engages over the needle cylinder edge and is provided in a known mannerwith two chamfers 5; 6.

Each sinker4 is mounted on a sinker driver 7 so as to swivel in the radial direction in relation to the needle cylinder 3 and can be acted upon in its radial direction bytwosinkercam control surfaces 8; 9which are formed according to the system at radially acting cam parts8a; 8b; 8cor9a; 9b; 9c.

The sinker drivers 7 are in each case provided with a foot 1 1,which engages in a sinkerdriver cam 10with respective cam parts 1 0a; 10b; 1 Ocwhich are adjustable in height and belong to a particularsystem, and are arranged in the grooves 12 of an annular component 13 mounted on the needle cylinder 3, the grooves l2oftheannularcomponent 13 being arranged in a staggered manner in the grooves 2 ofthe needle cylinder 3.

Thecircularknitting machine is configured for knitting single yarn backing fabrics. Accordingly, each latch needle 1 is provided with a control foot 14 and a pattern foot 15a or 15b. In orderto produce a 1:2 single yarn backing fabric, the needles are used in such a way that each third needle 1 has a pattern foot 15awhile all other needles I have a pattern foot 1 sub.

Cam parts 1617 are provided to guide the pattern feet 15a; whereas the cam parts 18; 19 guidethe pattern feet 15b and the cam parts 20 the control foot 14.

The cam construction shown in Figure 2 forthree sequential knitting systems is continuously repeated about the entire circumference of the needle cylinder.

In orderto adjustthe loop length ofthe laid-in yarn, the parts 8a and 9a ofthe sinker cam control surfaces 8; 9 of the knitting system shown on the right-hand side in Figure 2 can be adjusted in the radial direction and in opposite directions to one another.

Forthis purpose the parts 8a, 9a ofthe sinker cam control surfaces 8; 9 are provided on slides 21,22 which can be moved in opposite directions against the force of a compression spring by two circular cams 23; 24. The cams 23; 24 are rigidly connected to a shaft 27, theupperendofwhichcarriesa knurled nut28for setting the required loop length ofthe laid-in yarn.

The method of operation ofthe circular knitting machine is explained in detail in the following: When the latch needle 1 enters the knitting system shown on the right-hand side in Figure 2 the latch needles 1 provided with a clearing foot 15a are raised bythecam partl6,whilethesinkers4aresimul- taneously retracted in the axial direction via the foot 11 of the sinker drivers 7 bythe cam part 1 0a of the sinker cam 1 and swivelled radially inwards by the adjustable part 8a ofthe sinkercam control surface, so asto enable the laid-in yarn to be caught and formed into loops in a mannerwhich is known peruse. All the other needles 1 are drawn off by means oftheir feet 1 Sb engaging the cam part 18, and carry outa backing movement.

The binding yarn is delivered to all the needles 1 at the central cam system in Figure 2. For this purpose the cam part 19 raises the needles 1 provided with a pattern foot 15b, while all the latch needles 1 are subsequentlywithdrawnbythecam pa rts 17 or 19.

The binding yarn enmeshesthe laid-in yarn which has been caught by the latch needles 1 provided with a pattern foot 15a. When the needles 1 are moved downwards bythe cam parts 17 or 19 and the holding-down sinkers 4 are moved outwards by the radiallyactingcam part9bofthesinkercamcontrol surface 9, the binding yarn is looped overthe lower edge ofthe upperchamfer6 ofthe holding-down and knockover sinker4; the stitch is not cast off, but remainsontheclosed needle head and is held bythe lowersinker chamfer 6. The sinker movement in the axial direction caused bythe cam part10bofthesinker cam 10 acting on the feet 11 ofthe sinker drivers 7 is essentially in the direction opposite to that ofthe needles.

The back yarn is delivered to all the needles 1 at the knitting system on the left-hand side in Figure 2. For this purpose the needles 1 are firstly raised by the cam part 20 by means of their central foot 14. When the needles 1 are retracted, the holding down sinkers 4 are swivelled outwards by the radially acting cam part 9a and the binding and back yarn is looped over the lower edge of the lower sinker chamfer 5 in a manner which is known per se.

The sinker4 is moved out in the axial direction by the cam part 10e of the sinker cam 10 in a direction approximately opposite-to that of the needle movement.

The invention thus guarantees precise control, which is free from play, of both the axial and the radial movement ofthe sinker 4. In particular, it enables single yarn backing fabrics ofthe required quality to be produced on mach ines of the type in question and the loop length ofthe laid-in yarn to be accurately adjusted, without however being restricted to machinesfor producing single yarn backing fabrics.

Claims (9)

1. A circular knitting machine comprising a rotary needle cylinder, a plurality of needles mounted for longitudinal movement on the cylinder, a plurality of sinkers for cooperating with the needles to perform knitting strokes, the sinkers being pivotally mounted on sinker drivers mounted for movement longitudinally of the needles, sinker cam means for pivotally moving the sinkers radially inwardly or outwardly of the cylinder upon rotation thereof, and sinker driver cam means for moving the sinker drivers tongitudinallyofthe needles upon rotation ofthe cylinder.

2. A circular knitting machine according to claim 1, wherein the sinkers each include a pivotal connection to a said sinker driver, and first and second lever arms extending from said pivotal connection, and said sinker cam means includes first and second sinker cam control surfacesforcamminglyengaging said lever arms respectively.

3. A circular knitting machine according to claim 2 including adjustment meansfor concurrently adjusting the positions of the sinker cam surfaces radially of the needle cylinder.

4. A circular knitting machine according to claim 3 wherein said sinker cam control surfaces are mounted en slides movable againsttheforce of spring means by rotary cams mounted on a common shaft.

5. A circular knitting machine according to any preceding claim including means for adjusting the longitudinal position ofthe cam driver means.

6. Multisystem circular knitting machine, in particulara R/Lcircular rib knitting machine for producing single yarn backing fabrics, comprising needles which can be moved in their longitudinal direction in the grooves ofthe needle cylinder by a needle cam, and holding-down and knockoversinkers which are arranged between the needles, can be moved in the longitudinal direction ofthe needles and transverse to the latter and comprise a shaft formed as a two-armed lever, on which two sinker cam control surfaces, each of which acts on one ofthe lever arms, are provided on both sides of its bearing point, one ofthese sinker cam control surfaces moving the hed ofthe holding-down and knockover sinkertransversely in one direction and the other moving it transversely in the opposite direction, characterised in that the shaft ofthe holding-down and knockover sinker is mounted so as to swivel on a sinker driverwhich is also arranged between the needles and which can be moved in the longitudinal direction of the needles in the grooves, which are arranged in a staggered manner with respecttothe grooves in the needle cylinder, of an annular component mounted on the needle cylinder by means of a sinker cam arranged between the sinker cam control surfaces andthe needle cam.

7. Circular knitting machine according to claim 6 characterised in that the two sinker cam control surfaces at the knitting systems whose function is to deliverthe laid-in yarn can be moved partically in the radial direction so as to adjust the loop length of the laid-in yarn, and that the mobile parts of the two sinker cam control surfaces can be adjusted in the radial direction and in opposite directions to one another by a common adjusting element provided for each system.

8. Circular knitting machine according to claims 7 characterised in thatthe adjustable parts ofthesinker cam control surfaces are provided on slides which can be moved against spring resistance by a respective cam the common adjusting element representing a shaft connecting the two cams.

9. Acircular knitting machine substantially as herein described with reference to the accompanying drawings.