JPH0797460B2 - Switch - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention automatically detects a processing opportunity by detecting that an object such as a product to be processed is transferred to a predetermined position in a production line of an unmanned factory. The present invention relates to a switch used for activating various instruments and devices by detecting various objects such as when activating.

(Prior art and its problems) As a conventional switch of this kind, a limit switch is generally used in the past, and it is interlocked with an actuator that is displaced according to contact with an object, and displacement of the actuator due to pressing force from the object or The limit switch is configured to be switched between an on state and an off state upon return by a biasing mechanism such as a spring.

However, in the case of the conventional example having such a configuration, when the frictional force with respect to the displacement of the actuator increases, the return of the actuator to the predetermined position becomes poor, or the intrusion of water is caused by the poor seal of the switch case. Then, the contacts will be short-circuited, and further, contact defects due to welding, breakage, cutting chips or dust caught between the contacts, etc. will occur, and as a result, the object will be transferred to the predetermined position. There was a problem that a predetermined machine or device could not be started, processing defects of the product occurred, and the production line had to be stopped to repair the limit switch. As described above, stopping the production line, even temporarily, affects other production processes, and there is a problem that the production efficiency is significantly reduced.

To prevent this, there is a mechanism that prevents welding of contacts in order to reliably switch the limit switch from ON to OFF, or a peeling mechanism that forcibly turns OFF even if welding occurs. As a result, the frictional force against the displacement of the actuator increases, resulting in defective recovery, or when chips or dust are caught between the contact points of the limit switch and cannot be switched from the off state to the on state. In such cases, we could not deal with it, and we had no choice but to stop the production line and repair it.

(Object of the Invention) The present invention has been made in view of the above circumstances, and can be appropriately repaired by predicting the occurrence of a startup failure of various machines and devices associated with object detection,
The purpose is to prevent the occurrence of startup failure.

(Structure and Effect of the Invention) [Structure] In order to achieve such an object, the present invention has the following structure.

A first switch section, a second switch section that returns after a delay from the first switch section, and an on / off signal of a switch contact given from the first switch section, and responding to a rise of the on / off signal A first input circuit that outputs a detected pulse (first rising edge detection pulse) and a detection pulse corresponding to a falling edge (first falling edge detection pulse), respectively, and a switch contact from the second switch section. A second pulse that is supplied with an on-off signal and outputs a detection pulse (second rising edge detection pulse) corresponding to the rising edge of the on-off signal and a detection pulse (second falling edge detection pulse) corresponding to the falling edge The input circuit and the timer operation is started in response to the first falling detection pulse, A time-up signal is provided which is set longer than the period from the second input circuit to the second fall detection pulse when the second switch section is normal, and the time-up signal is set at the time-up time. And a timer circuit that resets the timer operation in response to the second falling detection pulse given before the time-up, and the timer when the contact of the second switch section is defectively restored. A recovery failure detection circuit section that outputs a failure prediction signal in response to the time-up signal given from the circuit, and a fall detection pulse on the other side of both switch sections when one of the switch sections is short-circuited between contacts In response to the failure, if a seal failure detection circuit that outputs a failure prediction signal and one of the switch parts has a contact failure, It is characterized by the PFA detection circuit including a contact failure detection circuit section for outputting a failure prediction signal in response to the falling of the other side edge detection pulse parts equipped with a.

[Action]

 The operation of this configuration is as follows.

When the contact of the second switch section has a poor recovery, the timer circuit gives a time-up signal to the recovery failure detection circuit section. The failure prediction detection circuit section outputs a failure prediction signal in response to the time-up signal. Further, when the contacts of one switch unit are short-circuited, the fall detection pulse of the switch unit on the other side is given to the seal defect detection circuit unit. A failure prediction signal is output from the seal failure detection circuit section in response to the falling detection pulse. Further, when the contact point of one of the switch sections is defective, the failure prediction signal is output from the contact failure detection circuit section in response to the fall detection pulse given from the input circuit on the other side.

〔effect〕

From the above, according to the present invention, the following effects are exhibited.

In a production line or the like, when a transferred object comes into contact with the actuator or a member interlocked with it, the actuator is displaced accordingly. When the first switch section and the second switch section are configured to be turned on / off according to the displacement of the actuator, an on / off signal is output from each of the first switch section and the second switch section. To be done.

Then, when the object is transferred and the application of the pressing force to the actuator is released, both switch parts are switched from off to on or from on to off. The on / off signals associated with the switching are given to the first input circuit and the second input circuit, respectively. The first input circuit outputs a first rising edge detection pulse corresponding to the rising edge of the on / off signal from the first switch section and a first falling edge detection pulse corresponding to the falling edge. The second input circuit outputs a second rising edge detection pulse corresponding to the rising edge of the on / off signal from the second switch section and a second falling edge detection pulse corresponding to the falling edge.

The timer circuit starts the timer operation in response to the first falling detection pulse, and is reset by the second falling detection pulse when the second switch section is normal. Further, when the contact of the second switch section is in a poor recovery state, the timer circuit outputs a time-up signal. This time-up signal is input to the failure prediction detection circuit.
The failure prediction detection circuit outputs a failure prediction signal in response to the time-up signal. Further, when one of the switch parts has a seal failure or a contact failure, it outputs a failure prediction signal in response to the falling detection pulse from the input circuit on the other side.

Therefore, according to the present invention, an increase in frictional force and swarf,
If the actuator does not return properly due to biting, etc.,
If an abnormality such as a defective seal due to water intrusion or contact failure due to welding or breakage of contacts, bite of cutting chips, etc. occurs, the failure prediction signal from the failure prediction detection circuit causes the switch As a result of being able to perform repairs in advance, it is possible to effectively prevent sudden stoppages of the production line by performing the repairs at night when the production line is stopped. Has come to be able to improve.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of essential parts of a switch according to an embodiment of the present invention. Reference numerals 1 and 2 respectively turn on and off when the transferred object comes into contact with an actuator (not shown) or a member interlocked with it in the production line or the like and the actuator is displaced accordingly, and outputs on / off signals S1 and S2 respectively. The second switch section. In this case, the second switch unit 2 is configured to return later than the first switch unit 1. 3 is given an on / off signal S1 of the switch contact from the first switch unit 1,
And the detection pulse corresponding to the rising edge of the on / off signal S1 (first rising edge detection pulse S3) and the detection pulse corresponding to the falling edge (first falling edge detection pulse S5)
The first input circuit 4 for outputting the ON and OFF signals S2 of the switch contact from the second switch section 2 and the detection pulse corresponding to the rising edge of the ON / OFF signal S2 (second rising edge detection pulse S4 ) And a detection circuit pulse (second falling detection pulse S6) corresponding to the falling edge, respectively.

5 is the second rising edge from the second input circuit 4 when the timer operation is started in response to the first fall detection pulse S5 and the second switch section 2 is normal after the timer operation is started. The time-up signal T is set longer than the period until the falling detection pulse S6 is given.
The timer circuit outputs S7 and resets the timer operation in response to the second falling detection pulse S6 given before the time is up.

Reference numeral 6 denotes a first D flip-flop 6a to which the output of the first switch unit 3 is applied, and an output of the second input circuit 4 and a contact failure of the second switch unit 2 A third D flip-flop 6c as a recovery failure detection circuit section which outputs a failure prediction signal S10 in response to a time-up signal S7 (clock) given from the timer circuit 5,
Seal shortage detection that outputs a failure prediction signal S11 in response to a first falling edge detection pulse S5 (clock) from the first input circuit 3 when a short circuit occurs between contacts of the second switch unit 2 (sealing failure). Failure in response to the second falling detection pulse S6 (clock) given from the second input circuit 4 when the contact between the fourth D flip-flop 6d as the circuit section and the first switch section 1 is defective. The second D flip-flop 6d as a contact failure circuit section that outputs the prediction signal S9
A failure prediction detection circuit including and. Failure prediction detection circuit 6
Is also an OR circuit 6ae that outputs the logical sum of the outputs of the first and third D flip-flops 6a and 6c, the output of the OR circuit 6e, and the outputs of the second and fourth D flip-flops 6b and 6d. It includes an OR circuit 6f that outputs a logical sum of and an inverter 6g.

Reference numeral 7 denotes an RS flip-flop (output circuit) that outputs each output of the first input circuit and the second input circuit 4 as a switch signal S12.

Next, the operation will be described with reference to FIG.

(A) When both switch parts 1 and 2 are normal [See Fig. 2 (a)]. ]: From the first switch unit 1, an on / off signal S1 having a rising time t0 and a falling time t1 is given to the first input circuit 3. In response to this, an ON / OFF signal from the second switch unit 2 having a rising time t0 and a falling time t2.
S2 is provided to the second input circuit 4. Then, the first
The input circuit 3 outputs a first rising detection pulse S3 at time t0 and a first falling detection pulse S5 at time t1, and the second input circuit 4 outputs a second rising detection pulse S5 at time t0. The rising detection pulse S4 and the second falling detection pulse S6 are output at time t2.

The timer circuit 5 is caused to start the timer operation by the first falling detection pulse S5 from the first input circuit 3, and is reset by the second falling detection pulse S6 from the second input circuit 4. To be Therefore, the timer circuit 5 does not output the time-up signal S7.

Further, the failure prediction detection circuit 6 does not output the failure prediction signal S13, and this switch only outputs the switch signal S12 from the output circuit 7.

(B) In the case where the second switch section 2 has a poor recovery [see FIG. 2 (b)]. ]: In this case, from the second input circuit 4, at time t4, the second
Since the falling edge detection pulse S6 of 1 is given to the timer circuit 5, the timer circuit 5 whose timer operation has already been started by the first falling edge detection pulse S5 from the first input circuit 3 Since the time is up at the time t3 before the falling detection pulse S6 is given, the time-up signal S7 is output from the timer circuit 5 as the first signal.
To the third D flip-flop 6a and the third D flip-flop 6c. Then, in this case, since the output of the second input circuit 4 given to the input section D of the third D flip-flop 6c is already at the high level at this time t3, the time-up signal S7 is given. The output of the third D flip-flop 6c thus obtained becomes high level at the time t3, and the high level output (fault prediction signal S1
0) is output as a failure prediction signal S13 from the failure prediction detection circuit 6 via the OR circuits 6e and 6f.

(C) In the case where the second switch section 2 has a poor seal [see FIG. 2 (c)]. ]: In this case, at time t1, the output of the second input circuit 4 is at the low level, so the high level output is given from the inverter 6g to the input part of the fourth D flip-flop 6d. Then, at the time t1, the input section D of the fourth D flip-flop 6d receives from the first input circuit 3 to the first
Since the trailing edge detection pulse S5 of F is supplied as a clock, at the time t1, the fourth D flip-flop
A high level output (fault prediction signal S11) is output from 6d. This high level output is output as a failure prediction signal S13 from the failure prediction detection circuit 6 via the OR circuits 6e and 6f.

(D) When the contact point of the first switch unit 1 is defective [see FIG. 2 (d)]. ]: In this case, since the first switch unit 1 outputs the high-level on / off signal S1, the first input circuit 3 does not output the first falling detection pulse S5.
Therefore, the timer circuit 5 cannot start the timer operation. Then, at time t2, from the second input circuit 4 to the second
When the up-and-down detection pulse S6 (clock) is input to the second D flip-flop 6b, the high level output from the first input circuit 3 is given to the input part of the second D flip-flop 6b. Iraka, the second D flip-flop
The output of 6b outputs a high level output (fault prediction signal S9) at time t2, and the high level output is an OR circuit.
It is output as a failure prediction signal S13 of the failure prediction detection circuit 6 via 6e and 6f.

As described above, according to this embodiment, in the case where each switch section has a defective return, a defective seal, or a contact short circuit, it is output as a failure prediction signal.

[Brief description of drawings]

The drawings relate to an embodiment of the present invention, FIG. 1 is an overall circuit diagram, and FIGS. 2A to 2D are timing charts for explaining the operation. 1 ... First switch section, 2 ... Second switch section, 3
...... First input circuit, 4 ... Second input circuit, 5 ... Timer circuit, 6 ... Failure prediction detection circuit, 7 ... Output circuit.

Claims (1)

[Claims] 1. A first switch section, a second switch section that recovers later than the first switch section, an on / off signal of a switch contact is given from the first switch section, and an on / off thereof is provided. A first input circuit that outputs a detection pulse (first rising detection pulse) corresponding to a rising edge of the signal and a detection pulse (first falling detection pulse) corresponding to a falling edge, and the second switch Is supplied with an ON / OFF signal of the switch contact, and a detection pulse corresponding to the rising edge of the ON / OFF signal (second rising edge detection pulse) and a detection pulse corresponding to the falling edge (second falling edge detection pulse), respectively. A second input circuit for outputting, a timer operation started in response to the first falling detection pulse, and a timer operation It has a time-up time set longer than the period from the start to the time when the second falling detection pulse is given from the second input circuit when the second switch section is normal, and the time A timer circuit that outputs a time-up signal at the time of up, and resets the timer operation in response to the second fall detection pulse given before the time up, and the contact of the second switch section is defectively restored. At the time of, a failure recovery detection circuit section which outputs a failure prediction signal in response to the time-up signal given from the timer circuit, and when one of the switch sections is short-circuited between contacts, Faulty seal detection circuit that outputs a failure prediction signal in response to a fall detection pulse and one of the two switch sections has a contact failure And a failure prediction detection circuit including a contact failure detection circuit section that outputs a failure prediction signal in response to a falling detection pulse on the other side of both switch sections.