GB2062019A

GB2062019A - Cam system for double-cylinder knitting-machine

Info

Publication number: GB2062019A
Application number: GB8030595A
Authority: GB
Original assignee: Elitex Zavody Textilniho; Elitex
Current assignee: Elitex Zavody Textilniho; Elitex
Priority date: 1979-09-28
Filing date: 1980-09-23
Publication date: 1981-05-20
Also published as: GB2062019B; DE3034785A1; IT8024940A0; IT1209356B; CS209007B1; DE3034785C2

Abstract

A cam system for two cylinder circular knitting machines for manufacturing hosiery and similar goods, has at least one feed for reciprocatory knitting, comprising both a left and a right clearing cam 11,12 and a triangular central cam 13. To avoid yarn disturbance or breakage, in the path A of the inoperative lifted needles or sliders are made, for either direction of rotation of the needle cylinder, on the central cam 13, behind each other, two lifting edges 130, 131 or 132, 133 for lifting the needles or sliders to an elevated position in which their upper ends are situated above the hooks of the knock over sinkers to prevent yarn from entering the latter and between them, on a cam part situated above the central cam, a retracting edge 211, 213, is made for retracting the needles or sliders to the original lifted position. <IMAGE>

Description

SPECIFICATION Cam system of two cylinder circular knitting machines for manufacturing hosiery and similar goods The present invention relates to a cam system for two cylinder circular knitting machines for manufacturing hosiery and similar goods, with at least one feed for reciprocatory knitting.

It is well known that in two cylinder knitting machines for manufacturing hosiery and similar goods, upon reciprocatory knitting heel or toe parts, the free yarn laid over the needle shanks is extended when being caught below the hooks of the knock over sinkers. The repeatedly cleared knock over sinkers bends the yarn between the needle shanks at a time, at which the preceding, already before cleared knock over sinker is still at the pointof maximum clearing, and thus cannot release the free yarn between the needle shanks.

Thus, yarn breakage takes place. This disadvantage is mitigated in the machines by a spring loaded sinker at the clearing point, or a special modification of the sinker rings at the clearing, which makes possible a slight opening of the knock over sinkers by the pull of the tensioned yarn, thus preventing a disturbance, or even breakage of the free yarn. However, in machines with coarse needle pitch, even those two methods are insufficient for preventing the free yarn to get into the hooks of the knock over sinkers, just because of the pitch and the thickness of the needles, or knock over sinkers.

The purpose of the present invention is to mitigate the above disadvantages, particularly for machines with rough needle pitch.

According to the invention there is provided a cam system for two cylinder circular knitting machines for manufacturing hosiery and similar goods, with at least one feed for reciprocatory knitting, comprising both a left and right cam and a triangular central cam, wherein in the path of the inoperative lifted needles or sliders for each direction of rotation of the needle cylinder are made on the central cam, behind each other, two lifting edges for lifting the needles or sliders to a height, in which their upper ends are situated above the hooks of knock over sinkers and between them, on a cam part situated above the central cam is made a retracting edge for retracting the needles or sliders to the original lifted position.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing in which Fig. 1 represents the cams of the feed for reciprocatory knitting together with the needle latch guide and the course of the path of knock over sinkers, bent for 900; and Fig. 2 is a partial axial section through the needle cylinder, representing the position of the slider above the hook of the knock over sinker.

A two cylinder circular knitting machine for manufacturing hosiery and similar goods is provided with a lower needle cylinder 1 (Fig. 2) and an upper, not represented needle cylinder. The lower needle cylinder 1 is mounted on an inner insertion piece 2, on which is fixed a withdrawing tube 3. In the tricks 4 of the lower needle cylinder 1 are mounted sliders 5 for holding needles 6 and below them further, not represented known jacks and selecting jacks. The needles 6 co-operate, upon loop forming, with knock over sinkers 7, which are mounted inside the tricks of sinker ring 8 and controlled by cam rings 9 and 10.

The machine is provided with two feeds of the same type, of which only one is specified for the purpose of explaining the present invention. In the path of the lower butts 51 of sliders 5 are mounted both the left and the right cam 11 and 12 (Fig. 1), a central cam 13 of triangular shape and an auxiliary cam 14. Furthermore, there are the left and right rising cams 1 5 and 1 6. In the path of the upper butts 52 of sliders 5 is arranged the left and right cam 17 and 18, a central auxiliary cam 1 9 and narrowing picker 20. For the purpose of guiding sliders 5, there is a cam ring 21, and a latch guide 22 for guiding the needle latches of needles 6.

Upon reciprocatory knitting, the distribution of needles 6 in operative and inoperative positions is performed in a known manner. For the direction of rotation S of needle cylinder 1 pass the lower butts 51 of lifted inoperative sliders 5 along path A and the lower butts 51 of operative sliders 5 along path B. The butts of the knock over sinkers 7 pass then along path C in both directions of knitting S and S'.

Upon reciprocatory knitting, guide V lays through opening 0 yarn P in the latch guide 22.

Upon rotation in direction S, when the first needles 6 of the inoperative group arrive at the point of laying yarn P, or at the opening 0, the knock over sinkers 7 are opened and, by lifting butts 51 of inoperative sliders 5 along lifting edge 1 30 of central cam 1 3 to an elevated inoperative position, the tips of sliders 5 are lifted above the hooks of the knock over sinkers 7, yarn P thus cannot be laid into the hooks of the opened knock over sinkers 7, as can be seen in Fig. 2. The tips of the sliders 5 are thus lifted from path D to path E.

However, immediately thereafter, the tips of sliders 5 are retracted along path E by means of retracting edge 211 of cam ring 21 , for the purpose of avoiding friction of yarn P between the tip of sliders 5 and the latch guide 22, and lifted again to the original level by lifting edge 131 of central cam 1 3. At that height, the inoperative sliders 5 move as far as the retracting edge 212 of cam ring 21, by means of which they are retracted into the original position, i.e. the tips into path D.

As can be seen, the sliders 5 are actually lifted to a higher level than the usual inoperative position at the point in front of the opening 0 as far as point II, at which the knock over sinkers 7 are closed, as can be seen from the course of path C of the butts of knock over sinkers 7. In that range of opened knock over sinkers 7 yarn P can be introduced into the needle hooks upon rotating in direction S, and therefore the tips of needle jacks 5 are blocking yarn P.

In a similar manner, upon rotation of needle cylinder 1 in the direction S', it is necessary to avoid that yarn P penetrates the open hooks of knock over sinkers 7 between opening 0 and point I, at which the knock over sinkers 7 are opened, as can be seen from the course of path C. This is again secured by lifting edge 132 of central cam 13, retracting edge 213 of cam ring 21, lifting edge 133 of central cam 13 and retracting edge 214 of cam ring 21. The said edges are symmetrical to edges 130, 21 1, 131 and 212 and their purpose identical.

Within the scope of the present invention, it is possible to use a central cam within the path of the upper butts of the sliders, retracting being possible to be performed by another cam part than the cam ring. The main advantage of the present invention consists in that penetration of yarn into the hooks of the opened knock over sinkers is safely prevented, whereby any yarn disturbance is avoided.

Claims

1. A cam system for two cylinder circular knitting machines for manufacturing hosiery and similar goods, with at least one feed for reciprocatory knitting, comprising both a left and right cam and a triangular central cam, wherein in the path of the inoperative lifted needles or sliders for each direction of rotation of the needle cylinder are made on the central cam behind each other two lifting edges for lifting the needles or sliders to a height, in which their upper ends are situated above the hooks of knock over sinkers and between them, on a cam part situated above the central cam is made a retracting edge for retracting the needles or sliders to the original lifted position.

2. A cam system as claimed in Claim 1, wherein the central cam is arranged within the path of lower butts of the needles or sliders.

3. A cam system for two cylinder circular knitting machines, substantially as hereinbefore described with reference to the accompanying drawing.