JPS5914465Y2 - Thread breakage detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a thread breakage detection device for a thread winding machine in a spinning factory.

Conventionally, a large number of yarn winding and unwinding devices are used in a spinning factory, and yarn breakage often occurs during the process.

It is necessary to quickly detect this thread breakage and take appropriate measures, and for this purpose a number of thread breakage detectors are used that utilize cam mechanisms or electrical contacts.

However, both are mechanically operated and are prone to breakdowns.
There are problems such as it is not suitable for high-speed operation, and it is necessary to apply a relatively large tension in advance to ensure reliable operation.

For this purpose, a method has been developed in which the vibration of the running thread or its position is detected using various detection elements such as charging elements, piezoelectric elements, or moving coils, but the electronic detection methods described above have high detection sensitivity and may be There are problems such as floating thread hairs, noise such as mechanical vibrations, or operation due to external signals unnecessary for soft inspection.To prevent these problems, measures such as supporting each detection element with an elastic body are taken. Although countermeasures have been taken, there is a drawback in that even these countermeasures cannot effectively prevent malfunctions.

An object of the present invention is to provide a yarn breakage detection device that can effectively distinguish between vibrations generated during yarn travel and mechanically induced external vibrations, and detect yarn breakages without malfunction. The object of the present invention is to eliminate the above-mentioned conventional drawbacks.

Hereinafter, the configuration of an embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is an electrical block diagram of this embodiment, in which the thread 2 released from the spindle 1 is wound onto the bobbin 3 of the winding machine, and the running thread 2 comes into sliding contact with the detection piece 4 and is detected by the arrow shown in the figure. The detection piece 4 is fixed to a piezoelectric element 5, and the output of the piezoelectric element 5 is input to a frequency discrimination circuit 6, and the output thereof is input to a voltage amplification circuit 7. It passes through a rectifying and smoothing circuit 8 and a voltage discrimination circuit 9, and its output is input to an output circuit 10.

Next, the operation of this embodiment will be explained with reference to the frequency discrimination characteristic diagram in FIG. 2 and the electric circuit diagram in FIG. 3.

When the thread 2 is wound around the bobbin 3, vibrations corresponding to the running speed of the thread 2 generated by sliding on the detection piece 4 are applied to the piezoelectric element 5, and the piezoelectric element 5 generates an electrical signal corresponding to the mechanical vibration. It is converted into a frequency (hereinafter simply referred to as signal voltage).

The frequency of the above-mentioned signal voltage is discriminated by a frequency discrimination circuit 6 which is a bypass active filter (single feedback type) consisting of R1-R6, C, C2 and an OP amplifier IC shown in FIG. (The characteristics of the discrimination circuit 6 are shown in FIG. 2), and the low frequency range is
Of the cut off signal voltage, only the high frequency portion corresponding to the running speed of the yarn 2 is output, and this signal is converted into a signal voltage of constant amplitude by the voltage amplification circuit 7 comprising the OP amplifier IC2.

The constant amplitude voltage is converted into an average value signal voltage by a rectifying and smoothing circuit 8 including a diode D□, a capacitor C5, and a resistor RIO.

Further, the average value signal voltage ■S is input to the inverting terminal of the voltage discrimination circuit 9 (voltage comparator) having hysteresis characteristics, while the reference voltage V obtained by R0□, R12, R13 and ■R1.

compared to As a result, if the result is ■5〈■o, the yarn is not running and the yarn is broken), and if V8〉■o, it is determined that the yarn is running, and when there is no running, the output of the OP amplifier IC3 is H.
level, and becomes L level when running, and the above output signal is input to the base of the output transistor Tr1 via the Zener diode ZD2, conducts or opens the transistor Tr1, and is connected to the collector. It is output via a pull-up resistor R15, and the output signal is used as an input signal to a stop device or for other driving purposes via a relay.

Further, in the above embodiment, a bypass, active filter circuit is used as the frequency discrimination circuit 6, but a bandpass or band elimination type frequency discrimination circuit 6 may be used.
It is also possible to use a plurality of magnetostrictive mechanical force filters to extract the change in vibration frequency immediately before yarn breakage, and to issue a prevention command to the machine before yarn breakage.

As mentioned above, since the running speed of the yarn 2 and the vibration frequency generated thereby are in a proportional relationship, if the cutoff frequency of the frequency discrimination circuit 6 is made to match the frequency generated by the running of the yarn 2,
There is an effect that thread breakage can be detected in a stable state without being affected by frequency fluctuations when the thread 2 starts running, and also without being affected by vibration frequencies generated by mechanical devices.

In addition, the cutoff frequency can be changed by simply changing the circuit constants of the frequency discrimination circuit 6, and since the frequency can be changed continuously, it is possible to easily cope with changes in the yarn count or running speed of the yarn 2. (However, if the frequency discrimination circuit has a passband width, the above effect can be obtained without adjustment.

). Next, the effects of the present invention will be explained.

The present invention consists of a piezoelectric element that comes into contact with the linear running part of the thread and generates an output at a frequency corresponding to the running speed of the thread, and a frequency discrimination system that allows only the output of a specific frequency from the piezoelectric element to pass when the thread is running normally. an amplifier circuit that amplifies the output from the frequency discrimination circuit; a rectifier and smoothing circuit that rectifies and smoothes the output from the amplifier circuit; The yarn breakage detection device includes a voltage discrimination circuit that generates an output by comparing it with a set reference voltage, and an output circuit that operates based on the output from the voltage discrimination circuit.

As a result, the present invention can detect normal running of the thread and thread breakage with high precision without applying almost any contact pressure to the thread.
Moreover, since yarn breakage detection can be performed at any position in the straight line travel of the yarn, the yarn breakage detection device of the present invention can be easily installed not only in winders but also in various textile machines where yarn travels. In particular, in the present invention, it is possible to reliably distinguish between yarn running and mechanical vibration without imparting any running resistance to the yarn as it is being wound, and without being affected by mechanical vibration. In addition to being able to reliably detect yarn breakage, it is also possible to easily detect a decrease in yarn running speed due to abnormal clutch/brake operation or belt loosening during winding.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a characteristic diagram showing its frequency discrimination characteristics, and FIG. 3 is its electrical circuit diagram. 2... Thread, 4... Sensing piece, 5...
...Piezoelectric element, 6...Frequency discrimination circuit, 7...
...Amplification circuit, 8... Rectification and smoothing circuit, 9.
...Voltage discrimination circuit, 10...Output circuit.

Claims (1)

[Scope of utility model registration request] a piezoelectric element that comes into contact with a linearly running portion of the thread and generates an output at a frequency corresponding to the running speed of the thread; a frequency discrimination circuit that passes only the output of a specific frequency from the piezoelectric element when the thread is normally running; an amplifier circuit that amplifies the output from the frequency discrimination circuit; a rectifier and smoothing circuit that rectifies and smoothes the output from the amplifier circuit; and a preset standard for the output from the rectifier and smoother circuit to correspond to normal running of the yarn. A thread breakage detection device comprising: a voltage discrimination circuit that generates an output by comparing the voltage; and an output circuit that operates based on the output from the voltage discrimination circuit.