GB2160550A - Cam system of a double-cylinder circular knitting machine - Google Patents

Abstract

The invention relates to a cam system of a double-cylinder circular knitting machine for the production of hosiery and the like goods with at least one knitting feed where in the path of a first butt (31) of each of the control jacks (3) there are left and right stitch cams (4, 6) and a central retracting cam (5). Axially aligned with the central cam (5) in the path of a second butt (32) of each of the control jacks (3) there is arranged a freely swingable double-sided retracting cam (7), the cam (7) taking over the control of the jacks (3) when the butt (31) passes between cams (5) and (4) or (6). <IMAGE>

Description

SPECIFICATION Cam system of a double-cylinder circular knitting machine The invention relates to a cam system of a doublecylinder circular knitting machine for the production of hosiery and the like goods with at least one knitting feed.

It is known that double-cylinder knitting machines for the production of hosiery goods are provided with knitting feeds designed for reciprocatory knitting of heels and toes. Said knitting feeds are provided with a left and a right stitch cam and a central cam which control the upper butts of the needle control jacks. The central cam is double-sided and retracts the needles to such a position that the butts of the control jacks are safely guided onto the working edges of the left and of the right stitch cam. But such arrangement of the central cam presents the following disadvantages.When changing stitch length the vertical portion of the beginning of the working edge of the stitch cam varies and for this reason the central cam must sink sufficiently deep which in turn has a disadvantage that the latches of the needles being retracted do not follow the latch guide and the needles get closed with consequent faults in laying the threads.

The object of the invention is to eliminate the above mentioned disadvantages. According to the invention there is provided a cam system for a double-cylinder circular knitting machine for the production of hosiery and the like goods with at least one knitting feed wherein in the path of a first butt of each of the needle control jacks are left and a right stitch cam and a central retracting cam, and vertically aligned with the central cam in the path of a second butt of each of the control jacks there is arranged a freely swingable double-sided retracting cam.An embodiment of the invention will now be described by way of example, with reference to the accompanying drawing, in which: Figure 1 shows an arrangement of the cams of a knitting feed to control the needle jacks with illustrated needle latches guide; and Figure 2 shows an axial section of the swingable cam mounting in the cambox.

A double-cylinder circular knitting machine for the production of hosiery and the like goods is provided,with a needle cylinder 1 in the longitudinal tricks of which there are shiftably movable double-hook needles 2 being held in control jacks 3 under which there are located further, not shown, jacks. The machine is provided with two knitting feeds, while to illustrate the invention only the cams controlling the control jacks 3 in the first knitting feed are illustrated. The first knitting feed contains a vertically adjustable left stitch cam 4, a central retracting cam 5 and a vertically adjustable right stitch cam 6, located in the path of upper butts 31 of control jacks 3.In the path of the lower butts 32 under the double-sided central retracting cam 5 there is a freely swingable double-sided retractable-cam 7 and beside it there is an auxiliary left retracting cam 8 and a right retracting cam 9.

Guide 10 is used to guide the latches of needles 2.

The double-sided retracting cam 7 is mounted by its pin 71 swingable in sleeve 11, while it is secured by a catch 12. The sleeve 11 is fixedly screwed by not shown screws to the cambox 13.

The axis of the pin 71 and of the sleeve 11 is inclined to the surface of the needle cylinder 1 so as to get the double-sided retracting cam 7 in both of its end positions as near as possible to the needle cylinder 1 and thus also to the butts 32. The distance between the beginning of each working edge of double-sided retracting cam 7 and the end of each working edge of the central retracting cam 5 in less than the distance between the upper edges of butts 31 and 32. Furthermore, the distance between the end of each working edge of the doublesided retracting cam 7 and the beginning of the working edge of each of the left and the right stitch cams 4, 6 in their lowest positions i.e. in the case of highest stitch length, is greater than the distance between the upper edges of butts 31, 32.

The operation of the above described arrangement is as follows. During rotary knitting in the direction S first the upper butts 31 of control jacks 3 impact the central cam 5 from the right, central cam 5 performs their partial horizontal direction until the moment when the lower butts 32 impact the double-sided retracting cam 7 which leans against the left auxiliary retracting cam 8 and are further retracted by said cam 8. Double-sided retracting cam 7 lowers the needles 2 into the position where the upper butts 31 get against the working edge of the left retracting cam 4 which further retracts them. The double-sided retracting cam 7 is switched into the position where it leans against the auxiliary left retracting cam 8 and is held there by the action of passing lower butts 32.

The courses of the butts 31 and 32 are in paths A and B. The latches of the needles 2 then precisely follow the guide 10 as is evident from the course of the curve C until closely before the position when the thread is laid into the hooks.

During reciprocatory knitting when the needles 2 pass in the first reverse revolution in the direction S1 first the upper butts 32 of the working group of control jacks 3 impact the central cam 5 from the left, they are partially retracted and then the control jacks 3 move in horizontal direction until the moment when the lower butts 32 impact the double-sided retracting cam 7 which is still in the position as when turning in the direction S. The first lower butt 32 switches by its pressure the doublesided retracting cam 7 over into the second position, shown in dashed line, until it leans against the auxiliary right retracting cam 9. Lower butts 32 and the control jacks 3 are retracted to the level of the right clearing cam 6 which retracts them by means of the upper butts 31 while the needles 2 form stitches.The courses of the butts 31, 32 are mirror images of paths A and B, as well as the course of the latches of the needles 2. When the working group of needles 2 has passed through the knitting feed, the direction of rotation changes from the direction S1 to the direction S and the needles 2 and the control jacks 3 pass through the knitting feed in the above described way as in rotary knitting.

The cam system may be modified so the cams 7, 8 and 9 are located in the path of the upper butts 31 and the cams 4, 5 and 6 are located in the path of the lower butts 32 of the control jacks 3.

Because retraction of the needles and of their control jacks towards the stitch cam is performed by two cams it is possible to perform delayed sinking of the needle and thus following of the latch guide by the needle latches is improved. Further the use of a double-sided retracting swingable cam permits safe retraction of the needle so that at any adjusted stitch length there is no danger of impact of a butt of the control jack against the beginning of the working edge of each of the stitch cams. Finally because the needle latch is guided further over the latch guide its stabilization takes place, which effects better laying of the thread.

Claims (3)

1. A cam system for a double-cylinder circular knitting machine for the production of hosiery and the like goods with at least one knitting feed wherein in the path of a first butt of each of the needle control jacks there are a left and a right stitch cam and a central retracting cam, and vertically aligned with the central in the path of a second butt of each of the control jacks there is arranged a freely swingable double-sided retracting cam.

2. A cam system according to claim 1, wherein the freely swingable double-sided retracting cam is in the path of lower butts of the control jacks, the distance between the beginning of each working edge of the freely swingable double-sided retracting cam and the end of each working edge of the central cam in less than the distance between the upper edges of the butts of the control jacks, and the distance between the end of each working edge of the freely swingable double-sided retracting cam and the beginning of the working edge of each of the left and right stitch cams is greater than the distance between the upper edges of the butts of the control jacks.

3. A cam system for a double-cylinder circular knitting machine, substantially as hereinbefore described with reference to the accompanying drawing.