GB2198753A

GB2198753A - Device to control a movable cam in knitting machines

Info

Publication number: GB2198753A
Application number: GB08728408A
Authority: GB
Inventors: Milan Fucik; Zdenek Rebeka; Miroslav Kopecny
Original assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Current assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Priority date: 1986-12-11
Filing date: 1987-12-04
Publication date: 1988-06-22
Anticipated expiration: 2007-12-04
Also published as: IT1223250B; IT8722934A0; DE3740720A1; GB8728408D0; GB2198753B; CS920786A1; CS261117B1

Description

1 f, f Device to control a Movable Cam

Description

2198753 The invention relates to a device to control a movable cam in a knitting machine, especially to control needles, jacks and the like by means of an electric motor such as a step motor or servomotor controlled by electronic programming device.

A small diameter circular knitting machine is known where the stitch density controlling cams, as described in EP 185 266, are each individually controlled by a step motor being kinematically coupled with the stitch density controlling cam holder. The actual kinematical coupling consists of a cam arranged on the shaft of a step motor, the cam leaning against a bearing arranged on a pin being fixed in said axially movable stitch density controlling cam holder. Further the machines of said types are provided also with radially movable cams which can be also controlled by a step motor. Nevertheless a kinematic transmission like that to control the stitch densitv controlling cams, ie an external cam, is not satisfactory, because with regard to its dimensions it is not able to secure respective postions of the radially movable cam.

The disadvantage of the above described device to control the stitch density controlling cam or radially movable cam is that each of said cams requires another arrangement of kinematic coupling, consequently it is _ierent s, necessary tc produce more parts of dil hapes and hence to use various technologies when machining them.

According to the invention there is provided a device to control a movable cam in a knitting machine, especially to control needles, j a c k s, e t c", by means of an electric motor controlled by an electronic programming device of the machine, wherein the electric motor is fixedly arranged on a holder of the cam while it is kine- matically coupled with a stationary part of the machine.

2 - 1) The main advantage of the invention is the fact that fixing of the electric motor directly on a slide enables i t s arbitrary arrangement, o r directing of its output shaf t towards the direction of the cam motion and thus the use of the same kinematic coupling with a stationary part of the machine, what results in unification of technologies of the elements of kinematic c o u p I i n g. Further, the possibility of different fixing does not limit the built-up space around the needle cylinder. When a screw drive is used, it is possible to use electric motors of a very low power.

Embodiments of the invention will now be described, bN- wav of example, with reference to the accompanying drawings, in which:- FiR I is a vertical S e C t i o n of a stitch density controlling cam with illustrated fixing of an electric motor and its kinematic coupling via a screw drive to a stationary part of the machine; Fig 2 is the same as Fig 1 but kinematic coupling is by a front cam; Fis 3 s h ow s the arranzement of a r) e 1 e c t r i c r. o t o r o: a radially movable car., with illustrated kinematic coupling via a screw transmission to a cam-box; and Fig 4 is the same as Fig 3, but kinematic coupling is realised by a front cam.

A known single-cylinder circular knitting machine production of hosiery goods is provide with a N-linder I in which there are needles 2 and f or the needle c.

f urther knowr,, n o t shown jacks. In ea_ 1,nitting fee there is a holder 4 arranged axially movably in a cam-boy.

On said holder 4 there is fixed a stitch density controlling cam, 5 designed to lower its counter-cam together with the needles 2. Holder 4 is provided with a horizontal arm in which is vertically fixed an electric motor 6. The electric motor 6 may be a step motor or a servomotor, while its rotation is controlled by a known, not m 1 r 1 shown, electronic programming device of the machine. The shaft of the electric motor 6 is provided with an external thread, by said thread the shaft is screwed into an internal thread in a horizontal projection 31 of the cam-box 3 creating thus a kinematic coupling of the electric motor 6 with the cam-box 3.

During the operation of the machine, for example when regularly decreasing the density in the leg portion, the current is'supplied to electric motor 6 by electronic programming device according to a programme which rotates the shaft clockwise. The shaft of the electric motor 6 is screwed into the opening in the projection 31 of the cam-box 3, consequently the electric motor 6 and thus the holder 4 or the stitch density controlling cam 5 are axially lowered. This increases lowering of the needles 2 and the fabric density is decreased. During f urther operation, the current of opposite polarity reverses the electric motor 6 shaft rotation and the density of the fabric mav be increased.

Kinematic coupling of the electric motor 6 with a StatLionary part c,-' the machine may lue r-,.'-.'.sed fror example by a front cam 7 (Fig 2) fixed at the end of the shaft of the electric motor 6. The working face of the front cam 7 leans, for example, against a fixed stop 8 which is fixed to the cam-box 3 or to the flange of the machine, in the case of a double-cylinder machine. Holder 4 ofthe stitch density controlling cam 5 is in this case under the action of a compression sprin? 9 arranRed in an. opening in the cam-bey 3. 1 Pstead fixed stop 8 it is possible to use a bearing and the front cam 7 leans against the outer race of said bearing to decrease friction. The bearing is arranged on a pin in the cambox 3.

The operation of said device is the same as that of the device, where kinematic coupling is a screw - 4 coupling, with the difference in that motion of the stitch density controlling cam 5 upwards is realised by the force of the compression spring 9.

Further, the device according to' the invention may be used to control a radially movable cam 10 (Fig 3) which is assigned to lower butts of intermediate jacks 11 located under the not shown needles in the needle cylinder 1. Radially movable cam 10 serves to raise the needles and it is arranged slidably in the cam-box 3 by means of its holder 12. At the end of the holder 12 there is a bush, in which there is horizontally arranged the electric motor 6'. The shaft of the electric motor 6' is also provided with a thread which is screwed into ai opepi n- in the cam-box 3. The electric motor 6' is also a Ste- r- .Dtor or a servomotor and, it is connected with electronic programming device of the machine.

Kinematic coupling with a stationary part of the machine or with the cam-box 3 may be performed also by means of a front cam 7' which leans against the pro- trusion of the cam-box 3. On the holder 12 there is 1 - a t e d movable 27 0 -- --r-.pression spring 9' leaning against radia!2.,.cam., 10 and against the cam-box 3 for the reason to force the front cam 7 onto said projection.

The butts of intermediate jacks 11 are of different heights. motor 6' according The current is then supplied into the electric to the programme of knitting by a commap.-I f rom, the electronic programming device. Due to the rctatio: of the shaft the electric motor 6' in both cases eS hor:Lz,.nally and the radiall y movable ca!-. s thus adjusted to influence the butts of intermediate jacks 11 Within the scope of the invention unified parts of kinematic coupling can be used to control various types of cams in circular knitting machines for the production of hosiery goods and electric motors can be accordingly 1 r j 16 variously arranged according to the requirements f or the built-up space. So, for example, to control the radially movable cam the electric motor may be directly in the axis of the cam holder and its kinematic coupling may bear against the stop on the machine f lange, making the space around the needle cylinder free. Said kinematic coupling may be for example realised so that in the shaft of the electric motor there is an opening with an internal thread into which is screwed an externally threaded pin. Alternatively the shaft may-be provided with a helical groove into which reaches from the side a fixed pin, etc. The arrangement according to the invention may be used also in other types of knitting machines, even i flat knitting machines.

6 -

Claims

1-5 2. A device to control a movable cam in a knitting m a c h i n e, especially to control n e e d 1 e s, j a c k s, etc, by m e a n s o f a n e I e c t r i c motor controlled b y a n electronic programming device of the machine, wherein the electric motor is fixedly arranged on a holder of the cam, while it is kinematically coupled with a stationary part of the machine.

2. A device as claimed in claim I wherein the shaf t of the electric motor is provided with a thread which is screwed into a stationary part of the machine.

3. A device as claimed in claim 1 wherein a cam is f ixed to the shaf t of the electric motor, said cam leaning against a stationary part of the machine, for example against the cam-box, while the movable holder of the cam is springloaded.

4. A device to control a movable cam in a knitting machine, substantially as hereinbefore described with referencEto Fig I of the accompanying drawings.

to contrc- a movable cam in a knitL-Jng machine, substantially as hereinbefore described with reference to Fig 2 of the accompanying drawings.

6. A device to control a movable cam in a knitting machine, substantiallv as hereinbefore described with reference to Fig 3 of the accompanying drawings.

7. A device to control a movable cam in a knitting ne, as hereinbefore described W4 th reference to Fiz 4 of the accompanying drawings.

1 Publi-shed 1988 at The Patent Office. State House. 66 71 High Holborn, London WC1R 4Tr FVrther copies may be obtained from The Patent Office, Sa2es B-anch. St May Cray Orpington!',eril BR5 3RD Printed by Multiplex techiuques ltd St Maiv Cray Kent Con 1187 1 1