GB1577474A - Fabric tensioning and withdrawing in circular knitting machines - Google Patents

Description

(54) FABRIC TENSIONING AND WITHDRAWING IN CIRCULAR KNITTING MACHINES (71) We, ELITE, koncern textilniho strojirenstvi of Liberec, Czechoslovakia, a Corporate Body organised and existing under the laws of Czechoslovakia do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to fabric tensioning and withdrawing in circular knitting machines.

Two cylinder knitting machines are known, in which a mechanical device is used for withdrawing and tensioning the knitted goods, said device comprising two circular operative elements, of which the vertical motion for the purpose of withdrawing and tensioning the knitted goods is col-.trolled by means of a cam in such a manner that both elements retain and tension the knitted goods alternatingly, whereupon the knitted goods are withdrawn by this alternate engagement. This device has the disadvantage that the knitted goods are withdrawn regularly about the whole circumference of the needle cylinder and thus also at those points at which no further loop courses are formed, whereby the knitted goods are excessively stressed.Further, this device cannot operate upon reciprocatingly knitting a heel or toe part, respectively, as it can be disengaged from operation only about the whole circumference of the needle cylinder.

The disadvantages of the device as specified above are overcome by a further known device in which there are used for the purpose of withdrawal and tensioning knitted goods circular segments arranged in two circles of which each is situated at another level, said segments being mutually staggered. Again in this known device said segments are controlled from a cam and operate in such a manner that one segment retains and the other tensions the knitted goods and vice versa, this operation being performed only about the circumference of the needle cylinder which corresponds to the given extend of co-operating segments. Thus it is possible to tension the knitted goods only at the points of forming loop courses, i.e., at the points of knitting feeds.Further, upon knitting a reverse heel, it is possible to lift one half of the segments into an inoperative position, whereupon the device can perform withdrawal and tensioning of the knitted goods at the point of forming the heel pouch.

However, this device has the disadvantage, that upon alternating the operation of co-operating segments, the knitted goods are released on a larger arc of the needle cylinder, this influencing unfavourably the loop forming, particularly upon knitting goods of cotton yarns, when streaks are formed in the goods in longitudinal direction.

The operative rings are made of elastic and resilient material, e.g. of rubber, in order to achieve a perfect thrust of the ring against the conical extension of the withdrawing tube, whereby the knitted goods are withdrawn along the whole length of the ring. The operation of resilient operative rings is good however, upon longer lasting usage, destruction and rupture of the ring take place due to ageing and fatigue, and thus also arise failures in the actual withdrawing and tensioning operation.

The purpose of the present invention consists in mitigating said disadvantages and in providing a simpler and more effective means for the withdrawal and tensioning of the knitted goods.

According to the present invention there is provided a circular knitting machine wherein vertically displaceable operative elements in the form of rods are arranged in a circle, the lower ends of which mount resilient plates at the lower ends of which plates are provided withdrawing feet of rigid material for cooperation with a frusto-conical extension of an inner withdrawing insert in a needle cylinder.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure I is an axial section through the needle cylinders with the withdrawing means in the upper cylinder; and Figure 2 is a diagram of the positions of separate operative elements in one section of the needle cylinder and of the course of the cam control paths.

A two cylinder circular knitting machine for manufacturing hosiery goods comprises a lower needle cylinder 1 and an upper needle cylinder 2, in the tricks of which are mounted needles (not represented), which co-operate upon forming knitted goods with sinkers 3 and 4. The sinkers 3 are controlled by not denoted cam rings, which are stationarily arranged on a non-rotary withdrawing insert 5 and an inner insert 6. The sinkers 4 are stationary and are arranged on an upper inner insert 7, which is rigidly connected to the upper needle cylinder 2, and to the upper end thereof is fastened a gear wheel 8, which also serves as a bearing for the rotary mounting of needle cylinder 2 on the upper flange 9 of the machine. Via gear wheel 8 and a further mechanical transmission (not shown), the upper needle cylinder 2 is driven from the lower needle cylinder 1.

The actual device for withdrawing and tensioning the knitted goods comprises operative elements 10, at the lower ends of which are mounted resilient plates 11 with fastened withdrawing feet 12 thereon, which are made of hard rigid material, e.g. nylon. The withdrawing feet 12 are provided with two bevels for engagement with the knitted goods, and bear against the frusto-conical extension of withdrawing insert 5, as shown in Figure 2, the knitted goods passing during the knitting operation between said insert 5 and withdrawing feet 12. The working width of each withdrawing foot 12 ranges over several needles, and thus its action upon the knitted goods is over a section of the circumference thereof.

The operative elements 10 are mounted vertically displaceably in body 13 and are loaded by springs 14. Body 13 is stationarily arranged at the upper end of inner insert 7. Inside body 13 a mandrel 15 is screwed, on which is a vertically displaceable rider 16, which is controlled by lever 17 via a mechanical transmission (not represented) from the control drum of the machine, for the purpose of lifting the operative elements 10 into an inoperative position, as specified below.

The operative elements 10 have on their upper ends slidable follower elements 18, said operative elements 10 being alternatingly divided into short ones lox, 103, 105 ... (Figure 2.) the follower elements 181, 183, 185 ... of which bear against cam 19, and long ones 102, 104,106 . the follower elements 182, 184,186 ... of which bear against cam 20. The cams 19, 20 are annular and are arranged stationarily on plate 21, which is mounted on stands 22 on the upper flange 9.

The device according to the present invention operates as follows: Upon rotation of the needle cylinders 1 and 2, body 13 rotates together with the operative elements 10, which follow with their follower elements 18, cams 19 and 20, being pressed thereagainst by springs 14, and performing vertical motions, thus bringing about both tensioning and withdrawing of the knitted goods.

In Figure 2, the embodiment of cams 19 and 20 is represented, which make possible both tensioning and withdrawing of the knitted goods in the following manner, at the loop forming points. The needle cylinders 1 and 2 rotate in the direction S. In the range of lobe 19' of cam 19 the operative elements 102, 104 . . remain in their lower position, while withdrawing feet 12 retain the knitted goods having been withdrawn by them after the preceding contact. The operative elements lOi, 103 ... by means of their follower elements 181, 183 ... contact the lobe 19', and are lifted and then drawn back by springs 14 to their lower position. The growing knitted goods are thus tensioned and withdrawn by means of operative elements 101, 103 ... and the operative elements 102, 104 ... perform the retaining step.Upon further rotation, the operation of operative elements 101, 103 ... and 102, 104 ... is alternated. The operative elements 101, 103 ... remain in their lower position and retain the knitted goods in a tensioned condition caused by means of lobe 19', the operative elements 102, 104 . or their followr elements 182, 184 ... respectively, contacting the lobe 20' of cam 20, are lifted and are withdrawn again by springs 14 into their lower position. The now knitted fabric is thus withdrawn and held in a tensioned condition over its whole circumference.

The actual action of each operative element 10 is as follows: Operative element 10 is lifted to its upper position, and thus with withdrawing feet 12 (Figure 2) becomes disengaged from the knitted goods. The neighbouring withdrawing feet 12 are then situated in the lower position and hold, or tension, the knitted goods. During the upward movement, the withdrawing foot 12 is returned by action of the resilient plate 11 in the direction from the centre, as permitted by the frusto-conical extension of withdrawing insert 5, thus being situated in a position opposite to the upper edge of the conical extension of withdrawing insert 5.Upon backward movement of withdrawing element 10 into the lower position, the withdrawing foot 12 bears at first by the edge of the lower bevel and thereafter also with the edge of the upper bevel against the knitted fabric, and withdraws and tensions it upon lowering along the conical extension of withdrawing insert 5. The resilient plate 11 permits a motion of the withdrawing foot 12 in the direction towards the centre and presses simultaneously with withdrawing foot 12 against the knitted goods.

The whole device can be disengaged from operation in such a manner that lever 17 lifts rider 16, its stops coming into contact with the follower elements 18, whereupon the operative elements 10 are lifted to an inoperative elevated position above cams 19 and 20.

After a modification of construction, it is possible to lift only one half of operative elements 10, whereby the operation of the device when reciprocatingly knitting a heel is made possible.

The provision of several bevels on a withdrawing foot 12, and of the resilient plate 11 is advantageous for various kinds of goods in preventing the damaging of the knitted goods or penetration of the knitted fabric by feet. A further advantage consists in that the withdrawing feet are made of relatively hard material, thus neither ageing, as with rubber, nor wear taking place.

Still another advantage of the present invention resides in that the circumferentiallysectional action of the operative elements makes possible a substantially arbitrary distribution of the lobes on the cams without an accurate arrangement thereof relative to the knitting feeds, and further in that the circumferentially-sectional action and alternating engagement make possible a substantially permanent withdrawal and tensioning of the knitted fabric about the whole circumference of the needle cylinder.

WHAT WE CLAIM IS: 1. A circular knitting machine wherein vertically displaceable operative elements in the form of rods are arrange in a circle, the lower ends of which mount resilient plates at the lower ends of which plates are provided withdrawing feet of rigid material for cooperation with a frusto-conical extension of an inner withdrawing insert in a needle cylinder.

2. A circular knitting machine as claimed in Claim 1, wherein at the upper ends of one group of operative elements is arranged a first cam control path, while a second cam control path is arranged at the upper ends of another group of alternately arranged operative elements.

3. A circular knitting machine as claimed in Claim 2, wherein the lobes on the cam control paths are mutually staggered.

4. A circular knitting machine as claimed in Claim 2 or 3, wherein the upper ends of the operative elements bearing against the cam paths are provided with slidable follower elements.

5. A circular knitting machine substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. direction from the centre, as permitted by the frusto-conical extension of withdrawing insert 5, thus being situated in a position opposite to the upper edge of the conical extension of withdrawing insert 5. Upon backward movement of withdrawing element 10 into the lower position, the withdrawing foot 12 bears at first by the edge of the lower bevel and thereafter also with the edge of the upper bevel against the knitted fabric, and withdraws and tensions it upon lowering along the conical extension of withdrawing insert 5. The resilient plate 11 permits a motion of the withdrawing foot 12 in the direction towards the centre and presses simultaneously with withdrawing foot 12 against the knitted goods. The whole device can be disengaged from operation in such a manner that lever 17 lifts rider 16, its stops coming into contact with the follower elements 18, whereupon the operative elements 10 are lifted to an inoperative elevated position above cams 19 and 20. After a modification of construction, it is possible to lift only one half of operative elements 10, whereby the operation of the device when reciprocatingly knitting a heel is made possible. The provision of several bevels on a withdrawing foot 12, and of the resilient plate 11 is advantageous for various kinds of goods in preventing the damaging of the knitted goods or penetration of the knitted fabric by feet. A further advantage consists in that the withdrawing feet are made of relatively hard material, thus neither ageing, as with rubber, nor wear taking place. Still another advantage of the present invention resides in that the circumferentiallysectional action of the operative elements makes possible a substantially arbitrary distribution of the lobes on the cams without an accurate arrangement thereof relative to the knitting feeds, and further in that the circumferentially-sectional action and alternating engagement make possible a substantially permanent withdrawal and tensioning of the knitted fabric about the whole circumference of the needle cylinder. WHAT WE CLAIM IS:

1. A circular knitting machine wherein vertically displaceable operative elements in the form of rods are arrange in a circle, the lower ends of which mount resilient plates at the lower ends of which plates are provided withdrawing feet of rigid material for cooperation with a frusto-conical extension of an inner withdrawing insert in a needle cylinder.

2. A circular knitting machine as claimed in Claim 1, wherein at the upper ends of one group of operative elements is arranged a first cam control path, while a second cam control path is arranged at the upper ends of another group of alternately arranged operative elements.

3. A circular knitting machine as claimed in Claim 2, wherein the lobes on the cam control paths are mutually staggered.

4. A circular knitting machine as claimed in Claim 2 or 3, wherein the upper ends of the operative elements bearing against the cam paths are provided with slidable follower elements.

5. A circular knitting machine substantially as hereinbefore described with reference to the accompanying drawings.