GB2256442A

GB2256442A - Mechanical take-off device for circular knitting machine

Info

Publication number: GB2256442A
Application number: GB9211655A
Authority: GB
Inventors: Milan Fucik
Original assignee: Uniplet AS
Current assignee: Uniplet AS
Priority date: 1991-06-07
Filing date: 1992-06-02
Publication date: 1992-12-09
Anticipated expiration: 2012-06-02
Also published as: ITMI921381A0; ITMI921381A1; JPH05195389A; CS175091A3; GB2256442B; CZ279622B6; IT1270880B; GB9211655D0

Abstract

A take-off device for a circular knitting, especially a double-cylinder, machine consists of two cooperating co-axial take- off elements (6, 7) between which knitwork is caused to pass one (6) being stationary and one (7) rotary and which are provided with helical surfaces (61, 71) of opposite thread. The helical surfaces may be provided on outer and inner surfaces of coaxial cylindrical members in another embodiment. Suction may also be provided. <IMAGE>

Description

MECHANICAL TAKE-OFF DEVICE FOR CIRCULAR KNITTING MACHINES The invention relates to a mechanical take-off device for circular knitting machines, especially double-cylinder, hosiery manufacturing machines, the device comprising two coaxial, each other adjacent round take-off elements of which one is rotatable, and between which knitwork is caused to pass.

A double-cylinder circular knitting machine for manufacturing hosiery, provided with a device of the above-mentioned type, wherein one of the take-off elements has an active surface with a helical pattern, is known. This helical surface is designed for cooperating with another round surface of a mating take-off element, said surface being provided with centripetal grooves for guiding the knitwork in wale direction. In operation, the two elements bear upon each other so that the element with helical surface which e. g. is not rotatable - cause the knitwork to move away from needles whereas the second element holds the knitwork and prevents it from being shortened in the course direction.

Although such device is reliable in operation, it is disadvantageous particularly when being used for processing threads from natural, relatively hard fibrous materials. In this case, especially when knitting the heel portion of a hose, while the knitwork is withdrawn in a single direction only, there occurs cutting off of the knitwork in regions between the increasing heel and instep or vamp portions thereof.

It is an object of the present invention to eliminate the drawbacks of prior art as hereinabove referred to and to provide an improved take-off device of this type, wherein the two take-off elements thereof are provided each with a helical, knitwork engaging surface, the leads of such helices being opposite each other.

An advantage of the invention is in the fact that the knitwork walls, both from the face and back thereof, are actually "screwed" while the opposite leads of helical patterns prevent the knitwork from being shortened. Apart from this, due to the perfect mutual engagement of the two surfaces with the knitwork therebetween, it is not necessary to thrust the two take-off elements to each other by a minimum force.

A preferred embodiment of the invention will hereinafter be described with reference to the accompanying schematic drawing in which Fig. 1 is a fragmentary axial sectional view of the two needle cylinders of circular knitting machine provided with the take-off device; and Fig. 2 is top view showing the opposite leads of helices on the two take-off elements, when viewed in the direction of take-off device axis.

As can be seen in the drawing, and particularly Figure 1 thereof, a well-known double-cylinder circular knitting machine comprises an upper needle cylinder 1 and a lower needle cylinder 2 in the respective longitudinal tricks of which there are provided well-known double-headed needles and needle controlling sinkers. In the lower cylinder 2, said needles cooperate with knock-over sinkers 3 while in the upper needle cylinder 1 with press-off sinkers 4.

The lower round take-off element 6 is fixedly attached to a stationary take-off tube 5 and its upper conical front has a helical surface 61 in the form of a helix with left-hand lead.

The upper round take-off element 7 is provided on its lower front with a corresponding surface 71 whose helical pattern has right-hand lead. As can be seen in Figure 2 of the drawing, the two leads of the helices 61, 71 have one and the same angle of inclination so that the helices intersect each other in some points.

The upper round take-off element 7 is mounted for reciprocation in a lower carrier ring 10 of press-off sinkers 4 and is fixed to vertically movable rods 8.

The rods 8 are received in said ring 10 as well as in an upper carrier ring 11 of the press-off sinkers 4. As a result of the foregoing, the lower round take-off element 6 does not rotate in operation with the lower needle cylinder 2 whereas the upper round take-off element 7 and the upper needle cylinder 1 are adapted to rotate together.

In operation, when knitting the hose welt, the knitwork increases, due to an in-knitted elastic thread, towards the centre while the upper round take-off element 7 is lifted into its uppermost position along the rods 8 by means of a well-known cam mechanism (not shown). After the welt has been completed, the upper element 7 is lowered and forces thus the knitwork onto the lower round take-off element 6. Simultaneously, a vacuum take-off is set in operation whereby the increasing knitwork is withdrawn downwards on the surface 61. The actual take-off step takes place so that the revolving knitwork is engaged from its face by the helical surface 71 and is displaced, owing to the lead of helical pattern, radially to the centre. In the same way and direction, the knitwork is displaced by the helical surface 61. It is to be understood that the knitwork is displaced only, since the opposite leads mutually annihilate their helical effects in the lead direction so that no shortening of the knitwork occurs.

Within the invention scope, it is also possible to provide the respective helical patterns on the outer, or on the inner cylindrical surfaces of two coaxial round take-off elements.

It is another advantage of the invention that the knitwork is actually stressed between the two take-off elements solely in the points of intersection of the two helices. Since this point, due to the relative motion of the elements, permanently changes its position, the knitwork is prevented from being cut through.

The device of the invention can be used in both double-cylinder, hosiery manufacturing knitting machines and single-cylinder machines to improve the withdrawal of heavy goods.

Claims

1. A mechanical take-off device for circular knitting machines, especially double-cylinder, hosiery manufacturing machines, comprising two coaxial round take-off elements bearing on each other and forming a passage for knitwork, the device being characterized in that the two take-off elements (6, 7) each have a network engaging surface provided with a helical pattern of opposite lead, respectively.

2. A mechanical take-off device according to Claim 1, wherein the mutually opposite leads of the two knitwork engaging surfaces (61, 71) have one and the same angle of inclination.