GB2174414A

GB2174414A - Single-cylinder circular knitting machine

Info

Publication number: GB2174414A
Application number: GB08607619A
Authority: GB
Inventors: Jaromir Kucera; Jan Kollmann; Jiri Oliva; Josef Pialek; Jan Zona; Ruzena Prochazkova; Kvetoslava Kovarikova
Original assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Current assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Priority date: 1985-04-03
Filing date: 1986-03-26
Publication date: 1986-11-05
Also published as: GB2174414B; IT8619965A0; GB8607619D0; DE3609178A1; IT1189190B; CS251880B1; CS246285A1; IT8619965A1

Abstract

The invention relates to a single-cylinder circular knitting machine for the production of hosiery and the like goods in rotary and reciprocatory knitting in at least one knitting feed with thread guides to which is assigned a device to move them into operational and non-operational positions. The invention solves the problem of elimination of catching the thread in knock-over sinkers belonging to raised non-operating needles 2 in reciprocatory running by moving the operating guide (12) into a raised position during passage of the non-operating needles (2) through the knitting feed, this being effected by a device consisting of a power element (14) assigned to the guide (12), switching means for the power element (14) and control means for the switching means. The power element may be an electromagnet or pneumatic cylinder and piston, the switching means may be an electric switch or air valve and the control means may be a cam. <IMAGE>

Description

SPECIFICATION Single-cylinder circular knitting machine This invention relates to a single-cylinder circular knitting machine for the production of hosiery and like goods by rotary and reciprocatory knitting in at least one knitting feed with thread guides.

It is known that in small diameter knitting machines for the production of hosiery and like goods undesirable closing of the thread in the hook of opened knock-over sinkers during reciprocatory knitting of heels or toes takes place, which is frequently a cause of the thread breakage during reciprocatory knitting.

Said disadvantage is eliminated by the use of auxiliary knock-over sinkers, the so-called bluff-sinkers, which close the hooks of opened knock-over sinkers so that they are not able to catch the thread. But said solution considerably complicates the design and control of the sinker cams. Further known solutions are sinker cams which are arranged so that in the place where the thread can be taken up, the knock-over sinkers are closed and immediately afterwards opened again so that the thread cannot get into the hooks. Further there are double-cylinder knitting machines known, where to avoid taking up the thread needle guide jacks or shaped needle shanks are used, but this cannot be applied in singlecylinder machines with regard to the differences as compared with double-cylinder machines.

According to the invention there is provided a single-cylinder circular knitting machine for the production of hosiery and like goods in rotary and reciprocatory knitting in at least one knitting feed with thread guides, comprising a device to move the operating guide into a raised position during passage of non-operating needles through the knitting feed during reciprocatory knitting, the device comprising a power element assigned to the guide, switching means for the power element, and a control device for the switching means.

The advantage of the invention consists in its simplicity and consequently in the possibility of simple design of the sinker ring cover with regard to high speeds of knitting and with regard to reciprocatory knitting in two knitting feeds.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic partial axial section of a needle cylinder, illustrating the operational position of the heel thread guide, when it lays the thread into the operating needles; Figure 2 is the same as Fig. 1, but the heel thread guide is in a raised position, when the non-operating needles are passing it; Figure 3 is a schematic track of operating needles through the knitting feed, illustrating the laying of the thread; Figure 4 illustrates schematically the position of the thread in operating needles when the guide is raised during passage of non-operating needles through the knitting feed; and Figure 5 illustrates schematically the control elements of the device to control the guide.

A known single-cylinder circular knitting machine for the production of hosiery and the like goods is provided with needle cylinder 1, in the longitudinal tricks of which there are needles 2 co-operating with knock-over sinkers 3 when forming the stitches. The machine is provided with a knitting feed for reciprocatory knitting which is provided in the track of the needles 2 with left and right stitch cams 4 and 5 (Fig. 3), with respective guard cams 4' and 5' and central cam 6 and raising cams 7, 8. Knock-over sinkers 3 are controlled by external and internal rings 9, 10 fixedly arranged in the cover 11. The threads are laid by means of guides of which only the heel thread guide 12 is illustrated to explain the invention.

The guides are controlled in a known way by vertically displaceable rods 13 which in turn are controlled by a not shown mechanical transmission by the control drum of the machine. To the end of the heel thread guide 12 is fixed an armature 14' of the electromagnet 14, the armature 14' being a swingable element of a device designed to move the guide into a raised position during passage of the non-operating needles 2' through the knitting feed. The device further contains a switch 15 connected to the circuit of the coil of the electromagnet 14. The switch 15 is assigned to the rotating cam 16 which controls its function and thus also the function of the electromagnet 14. The electric circuit of the electromagnet 14 and of the switch 15 further contains a switch 17, the function of which is controlled by the control device of the machine for example by a control drum.

The above described device operates as follows. During rotary knitting the switch 17 is off, so that the switch 15 and the electromagnet 14 are not energised and are thus out of operation. The guides are introduced into their function by means of rods 13. During reciprocatory knitting of the heel only the heel thread guide 12 operates and it is held in operation by the action of the spring 12', while the guide lays the thread P into the needles 2.

The track of the heads of the needles 2 through the knitting feed is illustrated in dashand-dotted line p (Fig. 3), while catching of the thread P or the beginning of forming the stitches takes place on the knock-over levei 0.

The angle a of laying the thread is acute. The switch 17 is closed, so that the switch 15 and the electromagnet 14 are energised. After passage of the last operating needle 2 which knits the longest heel course over the stitch cam 4, the armature 14' of the electromagnet 14 pulls the arm of the heel thread guide 12 against the action of the spring 12' and raises the guide 12 into a raised position, as illustrated in Fig. 2. Due to raising the heel thread guide 12 a change in the angle of the thread laying to a 1 (Fig. 4) takes place, said angle a 1 being less acute than the angle a. Thus it is impossible that the thread P be laid under the noses of opened knock-over sinkers 3 and no damage to the thread can take place.When the needle cylinder 1 turns to its limit position, the electromagnet 14 releases its armature 14' and the spring 12' returns the heel thread guide 12 back into operative position.

The whole cycle runs then in the same way but in the reverse direction of rotation. The electromagnet 14 is controlled by the switch 15, which interrupts the current supply into the electromagnet winding. The switch 15, or its function, is then controlled by the drive-on lobe of the cam 16, while the beginning and the end of the drive-on lobe of the cam 16 controls the moment of switching on and off the switch 15 and corresponds actually as to the time to the track of the non-operating needles 2' around the heel thread guide 12 within the range of the lowest number of nonoperating needles. During further knitting of reciprocatory heels, the heel courses are narrowed and then widened, due to which the arc of non-operating needles 2' changes. But this has practially no effect on actual knitting and on the possibility of catching the thread P in the knock-over sinkers.

Within the scope of the invention it is also possible to control the heel thread guide 12 by a pneumatic system, while the power element of the device, i.e. the electromagnet is replaced by a cylinder with a piston, which is connected with the guide. Further the switching member, i.e. the switch 15 is replaced by a feeding valve and its control element may be also a cam. The feeding valves are in this case connected to their air box of a pneumatic system.

Claims

1. A single-cylinder circular knitting machine for the production of hosiery and like goods in rotary and reciprocatory knitting in at least one knitting feed with thread guides, comprising a device to move the operating guide into a raised position during passage of non-operting needles through the knitting feed during reciprocatory knitting, the device comprising a power element assigned to the guide, switching means for the power element, and a control device for the switching means.

2. A single-cylinder circular knitting machine as claimed in claim 1, wherein to the guide is assigned an armature of an electromagnet, into the winding of which a first switch is connected, to the first switch is assigned a rotary cam, while a second switch is introduced into the electric circuit of the first switch.

3. A single-cylinder circular knitting machine substantially as hereinbefore described with reference to the accompanying drawings.