JPH0565608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a timing abnormality detection circuit for detecting an abnormality in the generation timing of a position signal from a proximity switch in a loom and stopping the loom.

Prior Art Conventionally, this type of timing abnormality detection circuit for a loom has not been known.

Problems to be Solved by the Invention Figures 2 and 3 show an example of a waterjet type loom. In this waterjet type loom, the warp threads 1 are opened and closed by a heald frame (not shown), and when the heald frame is opened, the weft threads 3 are injected together with water from the nozzle 2 and inserted into the opening of the warp threads 1.
The weft 3 is driven into the cloth 5 by the reed 4, and the cloth 5 is woven. The reed 4 is normally at the home position shown in Fig. 2, and each time the weft 3 is inserted into the opening of the warp 1 from the nozzle 2, it advances to the position shown in Fig. 3 and returns to the home position after driving the weft 3. Return to position. The tip of the weft yarn 3 ejected from the nozzle 2 reaches the catch cord 6, is driven in by the reed 4, and is captured by the catch cord 6 as the catch cord 6 is twisted by the spindle 7. The cutter guide 8 and the feeler head 9 are integrally fixed to the reed 4, and when the reed 4 moves forward, the weft 3
One end portion of is cut by cutter 10. Cloth 5
The catch cord 6 is wound up in the direction of the arrow as the cloth is woven, and the cutter 11 is wound around the weft 3.
Cut the other end. There are always three to five weft yarns (residual yarns) 12 that have not been cut by the cutter 11, and the feeler head 9 detects the weft yarns 3 when the reed 4 moves forward. The filler head 9 has a pair of electrodes 9 ₁ , 9 ₂
The presence or absence of the weft thread 3 is detected depending on whether or not the weft thread 3 is connected between the electrodes 9 ₁ and 9 ₂ . As shown in Fig. 4, this weft detection signal from the feeler head 9 is extracted and amplified by the amplifier 13 only when the position signal from the proximity switch is input, and the weft is stopped when the weft 3 is not inserted. It is output to the circuit 14. Here, the proximity switch is driven in synchronization with the advance of the reed 4 by a drive unit integrated with the movable system of the loom, and outputs a position signal at the time when the weft 3 being driven by the reed 4 should be detected by the feeler head 9 during driving. Occur. When the position signal from the proximity switch is input, the stop circuit 14 operates the brake 15 to stop the movable system of the loom, thereby stopping the operation of the loom, if the output signal of the amplifier 13 indicates no weft. Stop weaving of cloth. Furthermore, when the stop circuit 14 enters the stop mode or receives a stop signal by pressing an off button, etc., the stop circuit 14 operates the brake 15 in accordance with the position signal.

However, in this loom, if the position signal generation timing becomes abnormal due to a failure of the proximity switch, the amplifier 13 will not be able to extract the weft detection signal from the feeler head 9 at the time when the feeler head 9 should detect the weft 3, and the stop circuit 14 becomes unable to respond to the output signal from the amplifier 13, and problems such as blind weaving (weaving a cloth using only the warp threads 1 without inserting the weft threads 3) may occur.

Means for Solving the Problem The present invention provides a loom which has a means for extracting a weft detection signal from a feeler head using a position signal from a proximity switch, and which stops when the weft is not inserted according to an output signal from this means. , a detection means is provided which detects that the position from the proximity switch continues at the same level for a certain period of time or more and outputs a stop signal.

Function: When the loom is operating normally, the position signal from the proximity switch does not remain at the same level for more than a certain period of time, and the detection means does not output a stop signal. However, if the position signal continues at the same level for a certain period of time due to a failure of the proximity switch, etc., the detection means detects this and outputs a stop signal to stop the loom.

Embodiment As shown in FIG. 1, an embodiment of the present invention is provided with a timing abnormality detection circuit 16 in the waterjet type loom described above to detect when the position signal from the proximity switch continues at the same level for a certain period of time. Then, a stop signal is output to the stop circuit 14, and the brake 15 is activated to stop the movable system of the loom.

As shown in FIG. 5, this timing abnormality detection circuit 16 is composed of signal interval detection means consisting of a differentiating circuit 17, an integrating circuit 18, and a signal synthesizing circuit 19. Differentiate the signal. The integrating circuit 18 integrates a constant voltage with a predetermined time constant, but the differentiating circuit 1
It is reset by the output signal of 7. The signal synthesis circuit 19 operates when a start signal is applied from a circuit not shown, and determines when the output voltage of the integrating circuit 18 exceeds the reference voltage, and outputs a stop signal to the stop circuit 14. When position signals from the proximity switch are input at normal intervals _T1 , the output voltage of the integrating circuit 18 does not reach the reference voltage and the signal combining circuit 19 does not output a stop signal.
When the interval between position signals from the proximity switch becomes a certain interval T ₂ or more, which is larger than the interval T ₁ due to a failure of the proximity switch or a disconnection accident, the output voltage of the integrating circuit 18 exceeds the reference voltage and the signal combining circuit 19
A stop signal is output from the stop circuit 14 to the stop circuit 14.

FIG. 6 shows a specific circuit configuration of this embodiment, and FIG. 7 shows an example of its timing. Capacitor C2 and resistor R1 constitute a differentiating circuit 17, which differentiates the position signal and detects its rise. The capacitor C3, the resistor R2, and the transistor Q1 constitute an integrating circuit 18, and the voltage of the DC power source is integrated by charging the capacitor C3 from the DC power source through the resistor R2. The transistor Q1 is turned on by the output signal of the differentiating circuit 17, and the capacitor C
By discharging the charge of 3, the capacitor C
3 and the integral value by resistor R2 is reset. The siener diode ZD1, the transistor Q2, and the diode D1 constitute a signal synthesis circuit 19, and when the diode D1 is turned off by the start signal,
The output voltage of the integrating circuit 18 is a Zener diode.
It is applied to the base of transistor Q2 via ZD1. The output voltage of the integrating circuit 18 is the Zener voltage of the Zener diode ZD1 and the transistor Q.
When a reference voltage consisting of the sum of the base-emitter voltages of 2 is reached, transistor Q2 is turned on and a bottom level stop signal is output. When the start signal disappears (becomes low level), diode D1
turns on, the cathode side of the Zener diode ZD1 becomes low level, and the transistor Q1 remains off. As shown in Figure 7, the position signal from the proximity switch may not be generated (remains at a low level) or may continue to be generated (remains at a high level) due to a failure of the proximity switch. In either case, the stop signal is output after a time _T2 determined by the time constants of capacitor C3 and resistor R2 has elapsed since the last rise of the position signal.

Effects of the Invention As described above, according to the present invention, there is a means for extracting a weft detection signal from the filler head using a position signal from a proximity switch, and the output signal of this means is used to stop the weft insertion when the weft insertion is not performed. In a loom, when it detects that the position signal from the proximity switch has remained at the same level for a certain period of time, it issues a stop signal and stops the loom, so it detects an abnormality in the timing of the position signal generation due to a malfunction of the proximity switch, etc. can be stopped,
It becomes possible to prevent defects such as blind weaving due to the above abnormality.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a circuit section of an example of a loom to which the present invention is applied, Figs. 2 and 3 are plan views showing different states of an example of a loom, and Fig. 4 shows a circuit section of the same loom. FIG. 5 is a block diagram showing one embodiment of the present invention, FIG. 6 is a circuit diagram specifically showing the same embodiment, and FIG. 7 is a timing chart showing a timing example of the same embodiment. 16... Signal interval detection means.

Claims (1)

[Claims] 1. A feeler head that is provided integrally with the reed and detects the weft yarn when the reed moves forward, and a proximity switch that is driven in synchronization with the forward movement of the reed and generates a position signal.
and a means for extracting a weft detection signal by the feeler head based on the position signal from the proximity switch, and in a loom that stops when the weft is not inserted according to the output signal of the means, the position signal from the proximity switch is used. 1. A timing abnormality detection circuit for a loom, comprising a detection means for detecting that the loom has remained at the same level for a certain period of time and outputting a stop signal to stop the loom.