GB2158106A

GB2158106A - Circular knitting machine

Info

Publication number: GB2158106A
Application number: GB08505312A
Authority: GB
Inventors: Dieter Rothe; Dieter Laube; Siegfried Bottger
Original assignee: Kombinat Textima VEB
Current assignee: Kombinat Textima VEB
Priority date: 1984-04-27
Filing date: 1985-03-01
Publication date: 1985-11-06
Also published as: DE3505679A1; GB2158106B; FR2563543B1; DD224889A1; GB8505312D0; FR2563543A1

Abstract

A circular knitting machine comprises a rotary cylindrical needle carrier (5) on which is mounted a plurality of needles (1) and a plurality of sinkers (4). The needles each include a foot (13) which acts as a cam follower and engages in a path defined by a set of stationary needle cams (14) arranged around the cylindrical needle carrier. The sinkers (4) are each provided with a foot (7) which acts as a cam follower and engages in a path (8) defined by sinker cams. On rotation of the needle carrier, the needles and sinkers perform a relative reciprocal movement. Adjustment of the stroke of this reciprocal movement so as to adjust the stitch length is carried out by adjusting the angular position of the needle cams (14) relative to the sinker cams about the axis of the machine, by limited angular rotation of support ring (20), utilising an adjustment screw. <IMAGE>

Description

SPECIFICATION Circular knitting machine This invention relates to a circular knitting machine, particularly but not exclusively a RIL circular knitting machine.

It is known from DE OS 2408924 and 3108041 to provide a circular knitting machine in which needles and associated sinkers are reciprocally mounted on a rotary needle cylinder, the needles and sinkers being slidable lengthwise along respective axes parallel to the rotation axis of the cylinder. The needles and sinkers are provided with cam followers which engage stationery needle and sinker arms adjacent the cylinder, with the result that the cams and sinkers are slid back and forth along their axis to produce knitting. The arrangement is such that for each stitch, part of the movement required is carried out by the needle and part is carried out by the sinker. A substantially continuous cylindrical arrangement of needle and sinker cams is provided around the cylindrical needle carrier, to produce multiple stitch forming operations for each revolution of the needle carrier.This arrangement permits high operating speeds to be obtained.

The stitch length can be adjusted by raising or lowering the sinker cams, i.e moving them parallel to the axis of the needle cylinder.

A central length adjusting system such as is adopted in conventional R/L circular knitting machines, which operates by raising or lowering the needle cylinder is not feasible in this case, because not only the needles but also the sinkers are mounted on the needle cylinder. If it is desired to adjust the stitch length by axial adjustment of the cams, only small adjustments can be made, otherwise large needle movements are required in transition from cam to cam as the cylinder rotates, which may result in breakage of the needles.

The present invention provides an improved means of adjustment.

According to the present invention, there is provided a circular knitting machine comprising a needle and-a sinker each reciprocally mounted on a carrier and each provided with cam follower means, a needle cam and a sinker cam, means for producing relative rotation of the carrier and the cams about an axis in such a manner that the cams engage the cam follower means and produce relative reciprocal movement of the needle and sinker, and means for adjusting the relative angular position of the cams in relation to said axis such as to adjust the relative reciprocal movement of the needle and sinker.

By means of the invention a relatively small angular adjustment of the cams can produce relatively large adjustments of stitch length. When a plurality of needle and sinker cams are utilised, the cam followers may achieve substantially continuous engagement with the cams without substantial discontinuities being produced by the adjustment means in the path of the cam follower for the needle, thus minimising risk of damage to the needle.

The invention will now be described 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 a partial developed projection of the needle lock and sinker lock of the machine, Figure 3 is a partial section along the line II I-Ill of Figure 1, and Figures 4-6 are in each case a highly simplified representation of the needle guide cam and the sinker guide cam of a knitting system of the circular knitting machine according to the invention, when the needle guide cam is displaced relatively to the sinker guide cam in the peripheral direction of the needle cylinder.

The latch needles 1 of the circular knitting machine according to the invention are longitudinally displaceable in the grooves 2 of a rotary needle cylinder rotatable about its longitudinal axis. Between each two latch needles 1 is a sinker 4 which extends over the edge 5 of the needle cylinder and which is provided with a sinker edge 6 and also with a cam follower in the form of a foot 7 which engages sinker cams 29 (Figure 2) which define a sinker lock channel 8. Each sinker 4 is mounted on a lever 9 pivotable about its fulcrum 12 by two radially acting lock cams 10, 11.Each needle 1 has a cam follower in the form of a foot 13 which engages a cam in the form of a needle lock channel 14, the parts being so arranged that the needle cylinder contains four different kinds of latch needle 1 of which the respective feet 13a, 13b, 13c and 13d are situated at different heights on the needle shaft 15. For each type of needle there is thus a different needle lock channel 14a, 14b, 14c or 14d, as the case may be.

The needle lock channels 14a, 14b, 14c and 14d consist of different separate pieces 16, 17, 18 belonging to one system, for circular movement, tucking and knitting respectively, each such piece consisting of two lock parts 16a, 16b, and 17a, 17b, and 18a, 18b respectively. The lock parts 16a, 16b, 17a, 17b, 18a, 18b, forming the needle lock channels 14a, 14b, 14c, 14d are situated on segments 19 mounted on a ring 20 displaceable in the peripheral direction on a fixed supporting ring 21 of the machine (Figure 1 and Figure 2).

For this purpose the ring 20 is fitted with a fork 22 in which is guided a spindle 23 which is mounted between two stops 24a and 24b occupying a fixed position on the supporting ring 21 and of which the spindle nut 25 is positioned between the interior sides 26a and 26b of the said fork 22 (Figure 3).

To enable the sinking depth to be read the ring 20 is fitted with a pointer 27 to which corresponds a fixed graduated scale 28 (Figure 3).

The sinker lock channel made up of similar separate pieces each belonging to a particular system consists on the other hand of lock parts 29a, 29b mounted on a ring 30 in such a way that they are immovable in the peripheral direction, the said ring being screw-connected to fixed columns 31 mounted on the supporting ring 21 (Figure 1 and Figure 2).

The needle guide cam N and the sinker guide cam P corresponding to the lock parts 29a and 29b and belonging to a knitting system are shown in Figures 4, 5 and 6 on highly simplified lines. The distance required for the formation of a stitch of a preselected length and resulting from the relative movement between the needle 1 and the sinker 4 is shown by the resultant R.

If the needle guide cam N is displaced in the direction of the abscissa in relation to the sinker guide cam P which can be easily done by moving the ring 20 in the peripheral direction, the lowest point on the resultant R and thus the sinking depth K, changes, as may be seen from Figures 4-6, from a maximum value K,,,, (Figure 4) via a medium value KI,,, (Figure 5) to a minimum value K,, provided the ascent of the sinker guide cam P, after reaching the sinking depth, is made steeper than that portion of the needle guide cam N which takes the same direction.In order to ensure that the maximum needle expulsion will remain constant despite the change in the sinking depth K,, the ascent of the sinker guide cam P in the zone of maximum needle expulsion, in knitting or tucking, is equal to zero over a range Pcl which corresponds to the maximum possible displacement V,,, of the needle guide cam N in relation to the sinker guide cam P, which displacement, in the example selected, amount to 1;8 of the system width, SB.

The method of operation of the circular knitting machine to which the invention relates will be briefly explained hereinafter : On entering a knitting system (see arrow A in Figure 2) the latch needles 1 will be expelled for the purpose of knitting, 18a, 18b, or tucking, 17a, 17b, or will remain in circular motion, 16a, 16b, according to the arrangement of the feet 13 on the needle shaft 15 and according to the lock parts used, i.e. 16a, 16b, or 17a, 17b, or 18a, 18b.The movement of the sinkers 4 in the direction of needle expulsion and transversely thereto remains the same in each system; the sinkers 4 at each knitting point, after being "locked in", are moved in opposition to the "draw-off" direction of the corresponding needles 1 by the lock part 11, which acts on the lever 9, and, after the "knocking-over" of the stitch, in opposition to the needle expulsion movement, by the lock part 29b, as well as transversally thereto and inwards, by the lock part 10, which likewise acts on the lever 9 (see Figures 1 and 2). To alter the stitch length of the knitted product all that is required is to turn the spindle nut 25 in the appropriate direction.By the rotation of the spindle nut 25 the fork 11, against the inside 26a and 26b of which the spindle nut 25 rests, is moved in the direction of the spindle 23, the maximum adjustment distance being marked S, (see Figure 3). The adjustment of the fork 22 causes a rotation of the ring 20 in the peripheral direction and thus a change in the sinking depth K, as a result of the displacement of the needle guide cam in relation to the sinker guide cam, as has already been explained in detail by reference to Figures 4-6. The particular sinking depth selected in each case can be read from the scale 28 by means of the pointer 27 (Figure 3).

The rotation of the needle lock ring 20 in the peripheral direction therefore provides a simple means of centrally adjusting the strength within a relatively wide range without abandoning the continuous unbroken construction for the needle lock cam.

Conversely, as will be obvious, central strength adjustment could conceivably be obtained by rotating the sinker lock ring 30 in relation to the needle lock ring 20, without dispensing with the advantages offered by the teaching on which the invention is based. It would be equally conceivable for the sinking depth to be obtained by the adjustment, in the peripheral direction, of the lock parts corresponding to separate systems or portions of systems, continuous unbroken needle lock cam and sinker lock cam design still being preserved.

In the present example, the sinker lock parts 29a, 29b in order to allow for manufacturing tolerances, are additionally so constructed as to be individually displaceable in the vertical direction.

Claims

1. A circular knitting machine comprising a needle and a sinker each reciprocally mounted on a carrier and each provided with cam follower means, a needle cam and a sinker cam, means for producing relative rotation of the carrier and the cams about an axis in such a manner that the cams engage the cam follower means and produce relative reciprocal movement of the needle and sinker, and means for adjusting the relative angular position of the cams in relation to said axis such as to adjust the relative reciprocal movement of the needle and sinker.

2. A circular knitting machine according to claim 1 wherein one cycle of said reciprocal movement occurs over a given angle of said rotation about said axis and said adjusting means permits adjustment of the relative angular position of the cams over a range of 119 to 1;7 of said given angle.

3. A circular knitting machine wherein said carrier comprises a rotary cylindrical needle carrier, said sinker cams being mounted on a fixed support, and said adjustment means so arranged to adjust the angular position of the needle cam relative to the rotation axis of the needle carrier.

4. A circular knitting machine according to any preceding claim including a plurality of said needle and sinker cams arranged in respective groups at angularly spaced positions in relation to said axis, said adjustment means being arranged to adjust the relative angular position of the needle cam group and the sinker cam group.

5. A circular knitting machine according to any preceding claim including a plurality of different types of needles mounted for reciprocal movement on the carrier, and needle cams for operating the different needle types selectively.

6. Multi-system circular knitting machine, particularly an RIL circular knitting machine, with needles which are displaceable in their longitudinal direction in the grooves of the needle cylinders, by means of at least one "needle lock cam" formed by separate pieces following one another without a break and each belonging to one system, and between which extend sinkers which are movable transversally to the needles and also in the longitudinal direction of the latter by means of a "sinker cam" likewise formed by separate pieces following one another without a break, in order to cause the stance required for the formation of a stitch to be covered partly by the thread guiding needles and partly by the sinkers, which latter, after reaching the sinking depth, are moved downwards together with the needles in the same direction, characterised by the fact that at each knitting point the ascent of the sinker lock cam formed from similar separate pieces is made steeper after reaching sinking depth than that portion of the needle lock cam which takes the same direction, while the ascent of the sinker lock cam in the zone of the maximum needle expulsion is approximately equal to zero, and the sinker lock cam P and/or the needle lock cam are displaceable, in the peripheral direction, system by system and/or in the entirety, by a distance corresponding to about 1/9 to 1/

7 of the width of a knitting system 5B 7.Circular knitting machine in accordance with Claim 6, characterised by the fact that the needle lock cam N is made up of different separate pieces for circular movement, tucking and knitting, a number of types of needle being provided, the foot of each being positioned at a different height on the needle shaft, so that a needle lock channel is provided for each of them.

8. Circular knitting machine in accordance with claims 6 and 7, characterised by the fact that it is preferably only the needle lock cams that are made displaceable in their entirety in the peripheral direction.

9. Circular knitting machine in accordance with claim 8 characterised by the fact that the needle lock ring bears a fork which is connected thereto fast in rotation and in which is guided a spindle which is situated between two fixed stops and of which the spindle nut is positioned between the interior sides of the said fork.

10. Circular knitting machine in accordance with claim 9, characterised by the fact that the needle lock ring is fitted with a pointer to which corresponds a fixed scale on the supporting ring to enable the sinking depth to be read.

11. A circular knitting machine substantially as herein described with reference to the accompanying drawings.