GB2136832A

GB2136832A - Thread motion detector

Info

Publication number: GB2136832A
Application number: GB08405246A
Authority: GB
Inventors: Otakar Curda; Jaroslav Maxa
Original assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Current assignee: Elitex Zavody Textilniho; Elitex Koncern Textilniho Strojirenstvi
Priority date: 1983-03-18
Filing date: 1984-02-29
Publication date: 1984-09-26
Also published as: CS246465B1; IT1196054B; IT8420079A0; GB8405246D0; DE3407012A1

Abstract

A thread motion detector, particularly for circular knitting machines for manufacturing hosiery and similar goods which is controlled by means of a microcomputer, comprises an arm (1) with at least one thread guide (2) and a spring (4), said spring (4) bearing against a piezoelectric converter (5), which is wired into the control circuit of the machine. The running thread causes oscillation of the arm (1) which produces a signal indicative of correct operation. When the thread is not running the machine is stopped. <IMAGE>

Description

SPECIFICATION Thread motion control The present invention relates to a thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods.

The control devices hitherto known, which are used in small diameter knitting machines, respond upon thread tension, thread breakage or run-out of thread. The said control devices are designed on both the principles, either contact or contactless. The disadvantage of the said devices consists in that they do not respond upon thread breakage in proximity of the needle cylinder or in the thread guide, when e.g. the thread is trapped in the guide and its tension is neither increased nor released. If, in that feed, a plurality of threads is simultaneously fed, then the machine continues its operation upon the mentioned failure with a reduced number of threads, thus producing rejects. Due to the steadily increasing production rate of knitting machines, an increased number of rejects is thus produced for the reason as mentioned above, which can be detected only by the attendant.

The purpose of the present invention consists in removing the above mentioned disadvantage.

According to the invention there is provided a thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods, comprising an arm with at least one thread guide, with a spring attached thereto, which bears against a piezoelectric converter which is wired into the control circuit of the machine.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 represents the arrangement of the thread control in side view; Figure 2 shows the arms with the thread passages; and Figure 3 shows the wiring of the thread control.

A known one cylinder circular knitting machine for manufacturing hosiery and similar goods is provided with feeds, to which threads are fed in accordance with the number of thread guides provided in each feed. In each feed, a thread motion control for controlling machine stoppage is arranged. The actual thread motion control consists of arm 1, which is disposed vertically and of which the upper end is bent horizontally, four thread passage eyes 2 (Fig. 2) being provided for the threads P1,P2, P3, P4 which are guided from the bobbins to the separate thread guides (not represented) of one feed.In arm 1, pin 3 is mounted, on which compression spring 4 is fitted, of which the other end bears against the piezoelectric converter 5, which is fixed to the second vertical arm 6 of the control, both arms 1 and 6 being fixed to block 7, which is arranged on the guide frame (not represented). The swing of arm 1 is limited by stops 8, which prevent the damaging of the piezoelectric converter 5.

The piezoelectric converter 5 is connected to a non-inverting input of operation amplifier 9 (Fig. 3), of which the amplification is adjusted by means of resistors 10 and 11 wired thereto. To the output of operation amplifier 9 a circuit 1 2 for detection and evaluation of the signal for further evaluating circuits, e.g.

the controlling microcomputer of the machine, is wired. Furthermore, switch 13 and output terminal 14 are wired behind circuit 12, for the purpose of interconnecting a certain group of thread motion controls to make possible a restriction of the number of conductors to be interconnected.

The device specified above operates as follows: During the knitting operation, only one thread guide is mostly operative. So, e.g.

thread P, is fed to the needles and passes through passage 2 in a slightly bent direction, thus causing an oscillation of arm 1, due to the friction with passage 2, said oscillation being transmitted by spring 4 to the piezoelectric converter 5. Spring 4 is designed in such manner as to transmit useful oscillation of arm 1 to the piezoelectric converter 5, and preventing simultaneously its damaging.

The signal is transmitted via operation amplifier 9 and circuit 1 2 to terminal 14 and therefrom to the controlling microcomputer of the machine. This microcomputer secures by its program the testing of the separate thread motion controls in the separate feeds, according to the knitting program.

The main advantage of the present invention consists in that the feeding of threads to the machine at the time at which it should take place is reliably checked. In the opposite case, i.e. when the thread does not move, the machine is stopped by the command from the microcomputer. Instead of a passage eye, it is also possible to apply another thread guiding means, e.g. a suitably shaped wire attached to arm 1.

The present invention can be advantageously applied in circular knitting machines in such cases, in which a plurality of threads is fed to one feed. The present invention can be applied also in other branches of the textile industry, in which thread motion checking is necessary.

1. A thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods, comprising an arm with at least one thread guide, with a spring attached thereto, which bears against a piezo

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Thread motion control The present invention relates to a thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods. The control devices hitherto known, which are used in small diameter knitting machines, respond upon thread tension, thread breakage or run-out of thread. The said control devices are designed on both the principles, either contact or contactless. The disadvantage of the said devices consists in that they do not respond upon thread breakage in proximity of the needle cylinder or in the thread guide, when e.g. the thread is trapped in the guide and its tension is neither increased nor released. If, in that feed, a plurality of threads is simultaneously fed, then the machine continues its operation upon the mentioned failure with a reduced number of threads, thus producing rejects. Due to the steadily increasing production rate of knitting machines, an increased number of rejects is thus produced for the reason as mentioned above, which can be detected only by the attendant. The purpose of the present invention consists in removing the above mentioned disadvantage. According to the invention there is provided a thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods, comprising an arm with at least one thread guide, with a spring attached thereto, which bears against a piezoelectric converter which is wired into the control circuit of the machine. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 represents the arrangement of the thread control in side view; Figure 2 shows the arms with the thread passages; and Figure 3 shows the wiring of the thread control. A known one cylinder circular knitting machine for manufacturing hosiery and similar goods is provided with feeds, to which threads are fed in accordance with the number of thread guides provided in each feed. In each feed, a thread motion control for controlling machine stoppage is arranged. The actual thread motion control consists of arm 1, which is disposed vertically and of which the upper end is bent horizontally, four thread passage eyes 2 (Fig. 2) being provided for the threads P1,P2, P3, P4 which are guided from the bobbins to the separate thread guides (not represented) of one feed.In arm 1, pin 3 is mounted, on which compression spring 4 is fitted, of which the other end bears against the piezoelectric converter 5, which is fixed to the second vertical arm 6 of the control, both arms 1 and 6 being fixed to block 7, which is arranged on the guide frame (not represented). The swing of arm 1 is limited by stops 8, which prevent the damaging of the piezoelectric converter 5. The piezoelectric converter 5 is connected to a non-inverting input of operation amplifier 9 (Fig. 3), of which the amplification is adjusted by means of resistors 10 and 11 wired thereto. To the output of operation amplifier 9 a circuit 1 2 for detection and evaluation of the signal for further evaluating circuits, e.g. the controlling microcomputer of the machine, is wired. Furthermore, switch 13 and output terminal 14 are wired behind circuit 12, for the purpose of interconnecting a certain group of thread motion controls to make possible a restriction of the number of conductors to be interconnected. The device specified above operates as follows: During the knitting operation, only one thread guide is mostly operative. So, e.g. thread P, is fed to the needles and passes through passage 2 in a slightly bent direction, thus causing an oscillation of arm 1, due to the friction with passage 2, said oscillation being transmitted by spring 4 to the piezoelectric converter 5. Spring 4 is designed in such manner as to transmit useful oscillation of arm 1 to the piezoelectric converter 5, and preventing simultaneously its damaging. The signal is transmitted via operation amplifier 9 and circuit 1 2 to terminal 14 and therefrom to the controlling microcomputer of the machine. This microcomputer secures by its program the testing of the separate thread motion controls in the separate feeds, according to the knitting program. The main advantage of the present invention consists in that the feeding of threads to the machine at the time at which it should take place is reliably checked. In the opposite case, i.e. when the thread does not move, the machine is stopped by the command from the microcomputer. Instead of a passage eye, it is also possible to apply another thread guiding means, e.g. a suitably shaped wire attached to arm 1. The present invention can be advantageously applied in circular knitting machines in such cases, in which a plurality of threads is fed to one feed. The present invention can be applied also in other branches of the textile industry, in which thread motion checking is necessary. CLAIMS

1. A thread motion control, particularly for circular knitting machines for manufacturing hosiery and similar goods, comprising an arm with at least one thread guide, with a spring attached thereto, which bears against a piezo electric converter which is wired into the control circuit of the machine.

2. A control as claimed in Claim 1, wherein a pin is mounted in the arm, on which is fitted a compression spring, said arm being disposed vertically, while its upper part, in which the thread guide is provided, is bent horizontally.

3. A thread motion control substantially as hereinbefore described with reference to the accompanying drawing.