JPH083457B2 - Switch with failure prediction function - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a switch capable of knowing a failure state in advance.

[Prior art and its problems]

Conventionally, there are a plunger type limit switch having a snap-action switch built into the housing and having an operating plunger protruding to the outside of the housing, and a roller lever type limit switch for converting the rotational movement of the roller lever into a linear movement.

However, in these switches, cutting oil adheres between the operation plunger and the head, or between the rotating shaft supporting the roller lever and the head, and the cutting oil solidifies or the cutting powder adheres to the operation plunger. There is a possibility that the roller lever and the movable portion including them may cause a return failure, or overtravel, that is, insufficient movement after the operation, or, in the roller lever type, an operation failure, that is, a setting failure due to wear of the roller.

On the other hand, the built-in switch may cause contact failure due to welding of contacts or dust adhering to the contacts, or breakage of the movable contact plate, which may cause product failure in the mechanical device using the switch. , It may be necessary to stop the production line to repair the switch.

[Object of the Invention]

In view of such conventional problems, the present invention solves various drawbacks of a built-in switch, especially a snap-action switch, and also improves the setting of operators such as a switch operating plunger and a lever, and a movable part of the switch. The purpose is to know the recovery failure in advance.

[Outline of Invention]

In order to achieve the object, the present invention replaces the switch built in the housing with a snap-action switch, uses an optical sensor, and the optical sensor is arranged along the moving direction of the actuator that optically opens and closes the optical sensor. Two sets of optical sensors are provided. While the outputs from these two sets of optical sensors are provided, one optical sensor obtains a switch output, the other optical sensor obtains a diagnostic output, and one optical sensor outputs no output. In this case, one of the photosensors is judged to be defective, and instead, the diagnostic output of the other photosensor is changed from the output that appears next to the switch output, and even when one photosensor fails. The output signal of the switch is continuously obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIG. 1 and FIG. 2, the housing 1
The head 3 is detachably attached to one end, that is, the head, on the axis of the. A rotary shaft 4 is arranged in this head so as to extend in a direction intersecting the axis of the housing 1. One end of the rotary shaft 4, that is, a portion protruding from the head 3, is connected with an operator 5, that is, one end of a lever, and a roller 6 is rotatably supported at a free end of the lever. A cam portion 7 having a flat surface is formed on a portion of the rotary shaft 4 located inside the head 3,
A cup plunger 8 is in contact with one surface of the cam portion by a spring 9. One end of the internal plunger 11 is in contact with the other surface of the cam portion 7, and the other end extends into the housing 1. This internal plunger converts the rotational movement of the operating element 5, that is, the rotary shaft 4, into a linear movement along the axis of the housing 1. A diaphragm seal 12 is provided between the housing 1 and the head 3 to control the seal therebetween, and an inner plunger 11 penetrates airtightly through a central portion of the seal. A built-in switch 13 is housed in the housing 1. This switch is the third
As shown in the figure, it has a case 14, and this case has an actuator.
15 are arranged along the axis thereof. This actuator is formed of a non-translucent material in the shape of an elongated plate, and has a first position along the axis of the case 14, that is, a free position before movement,
It is reciprocally supported between the second position, that is, the operating position after the movement. A plunger 17 is connected to one end of the actuator, and the plunger projects to the outside of the case 14. A cap-shaped seal member 18 is provided between the plunger and the case 14 to control the seal between them. Further, a spring 19 is provided between the other end of the operator 15 and the case 14, and the operator 15 is always urged to the first position, that is, the free position side by this spring.

Further, one end of the operating lever 21 is provided with a pin 22 in the housing 1.
It is rotatably supported by its free end, which abuts against the plunger 17, and the middle part thereof has an internal plunger 11.
Abut with the other end of. Thereby, the actuator 15 is interlocked with the movement of the operator 5.

Two optical sensors 23, that is, a first optical sensor 23a and a second optical sensor 23b are accommodated in the case 14.
This optical sensor is a light emitting element 25 that optically opposes each other.
And a light receiving element 26, and a predetermined space is provided between both elements. The two optical sensors 23a and 23b are arranged so that the operator 15 optically separates the light projecting element 25 and the light receiving element 26 from each other and maintains a predetermined interval in the moving direction of the operator 15. It is arranged.

On the other hand, the actuator 15 has a pair of translucent windows 27, 28 for selectively guiding the light from the respective light projecting elements 25 of the optical sensors 23a, 23b to the light receiving element 26 in the moving direction thereof, that is, the axial center of the case 14. They are spaced apart from each other in the line direction. The two translucent windows and the two optical sensors 23a, 23b have a positional relationship such that the operation start time of one optical sensor 23a and the operation start time of the other optical sensor 23b are different from each other when the actuator 15 is moved. Have And in this embodiment, the first
Optical sensor 23a is set to output as a switch, and when the actuator 15 moves from the first position to the second position, it works before the second optical sensor 23b,
It outputs the operation output as a switch. The actuator 15 is the second
When returning from the position of to the first position, the first optical sensor 23a returns after the second optical sensor 23b returns,
At this time, the return output is set.

On the other hand, the second optical sensor 23b is for outputting a normal diagnostic output, and outputs the diagnostic output after the first optical sensor 23a outputs the operation output and before the first optical sensor 23a outputs the return output. Is set to output a return signal.

In FIG. 4, the case 14 is covered with a cover 29, and an electronic circuit board 30 forming an electronic circuit is attached to the cover 29.

The opening of the housing 1 is covered with a cover 31.

In the above structure, when the operating element 5, that is, the lever rotates from the free state about the rotary shaft 4, the amount of rotation thereof is changed into a linear change amount of the internal plunger 11, and the operator 15 is further pressed through the lever. When this actuator is in the free position, as shown in FIG. 5 (a), the light emitted from the light projecting element 25 of both optical sensors 23a and 23b is blocked by the operator 15 and reaches the light receiving element 26. do not do.

Next, when the actuator 15 reaches the position shown in FIG. 5B in the process of moving from the free position to the operating position against the spring 19, the first transparent window 27 causes the first transparent window 27 to move the first position. The light emitted from the light projecting element 25 of the optical sensor 23a reaches the light receiving element 26. The resultant operating output as switch from the first optical sensor 23a, as shown at time t ₁ of FIG. 6 is issued.

Further, when the operator 5 reaches a predetermined rotation amount, the actuator 15 reaches the position shown in FIG. 5C, and the light emitted from the light projecting element 25 of the second optical sensor 23b by the second light transmitting window 28 is emitted. Is its light receiving element 26
The second optical sensor as shown at time t ₂ in FIG.
23b emits a diagnostic signal. In this state, both optical sensors 23a and 23b are operating.

At this time, when the overtravel is insufficient, that is, when the operator 15 starts to return after the first optical sensor 23a operates and before the second optical sensor 23b operates, the setting of the operator 5 is defective, that is, the operator 15 is sufficient. Then, the failure prediction output indicating that the setting is defective is performed assuming that it has not moved to the operating position. As shown in FIG. 6, this detection is performed at the time t _1, that is, at the time when the first optical sensor 23a is operated, by a timer counter (not shown) starts counting, and then the second counter is reached until a predetermined count is reached. This is done when the optical sensor 23b of does not operate.

Next, when the operating element 5 is in a sufficient operating position, that is, the operating element 15 is in the second position, the external force applied to the operating element 5 is removed, and the operating element is moved to its original position by the spring 9 and the cup plunger 8. Start returning to. At the same time, the actuator 15 is moved to the second position by the urging force of the spring 19 as shown in FIG.
From the first position, that is, the operating position, toward the first position, that is, the free position. Its actuator 15 as opposed to the by connexion prior to block light reaching the light receiving element 26 from the light projecting element 25 of the second optical sensor 23b at time t ₃ of Figure 6. That is, the second optical sensor 23b returns. At this point in time, a timer counter for defective recovery (not shown) starts counting.

When the operator 5 is completely returned to the original position and the actuator 15 is returned to the first position, that is, the free position, at the time t ₄ in FIG. 6, the operator 15 projects the first optical sensor 23a. The light from the optical element 25 to the light receiving element 26 is blocked, and a return output as a switch is emitted. At the same time, the timer counter stops counting.

At this time, when the count number of the timer counter becomes equal to or more than the preset value, a failure prediction signal is output. On the contrary, if the count number is smaller than the default value, the timer counter is initialized.

Next, the actuator 15 moves from the first position to the second position again, and even when the time point t ₅ in FIG. 6 is reached, the first optical sensor 23
a does not work, it actuator 15 continues to move, the optical sensor when the second optical sensor 23b issues a diagnostic output when it reaches the time point t ₆ of the drawing than the first optical sensor 23a Also outputs the output first, and this determines that the first optical sensor 23a has failed. At the same time, this fault condition is displayed externally.

Then, when the actuator 15 enters the return operation, the time point t _{7 in} FIG.
In, the second optical sensor 23b is restored, but the actuator 15 is further moved, and even when the time point t ₃ in the figure is reached, the first optical sensor 23a is out of order because it is out of order. Further, the actuator 15 returns to the first position as it is.

Further actuator 15 is aerodrome moved from the first position to the second position, the first as well as the optimum connexion also time t ₅ to time t ₉ in FIG. 6
The optical sensor 23a does not output an operation output.

Then, when the actuator 15 further moves and reaches the time point t ₁₀ in FIG. 6, the second optical sensor 23b outputs an output, but from this time point, the output is not the diagnostic output, that is, the operation output of the switch instead of the diagnostic output. And the actuator 15 reaches the second position.

Next, when the actuator 15 begins to aerodrome returned from the second position to the first position, the second optical sensor 23b is restored at time t ₁₁ of FIG. 6, at the same time emits the return output of the switch.

Similarly, the switch output, that is, the operation output and the return output thereof are output only by the second optical sensor 23b.

Control of output signals of these switches and failure prediction control can be performed by using a computer, for example, a microcomputer.

That is, while the actuator 15 reciprocates between the first and second positions, while the outputs of both the optical sensors 23a and 23b are present, the switch output is obtained by the first optical sensor 23a and the second optical sensor 23a is obtained. Although the diagnostic output is obtained by the sensor 23b, when the output of the first optical sensor 23a is exhausted, the failure of the first optical sensor is diagnosed by the second optical sensor 23b, and the second sensor 23b is further diagnosed. The diagnostic output of is changed to the switch output from the next output.

In addition, the setting failure of the manipulator 5 is the number of counts from the output time point of the first operating optical sensor, and the two optical sensors 23a, 23
This is done by detecting the operating state of b.

Further, the defective return of the movable part such as the operator 5, that is, the lever, the rotary shaft 4, the cup plunger 8, the internal plunger 11, the operating lever 21 or the operator 15 is detected by the count number from the output time point of the optical sensor which has previously returned. To be done.

Further, although the roller lever type is shown as the manipulator 5, a lever can be used for a normal lever type, and an external plunger can be used for a plunger type.

The block diagram shown in FIG. 7 is for predicting a switch failure by using a well-known computer, and the CPU 34 is a normal CPU including an arithmetic unit, a control unit, a memory, and a timer counter.
Has all the functions of a CPU. The CPU includes a driver circuit 35, 35 for driving the light emitting elements 25, 25 and a light receiving circuit 36, 36 for converting an optical signal from the light receiving element 26, 26 into an electric signal.
Are connected respectively. The CPU 34 has a constant voltage circuit 37,
Control output driver circuit 38, control output display circuit 39, output transistor diagnostic circuit 40, failure prediction output driver circuit
41, a failure prediction display circuit 42, etc. are connected, a control output display circuit 39 has an indicator light 43, a failure prediction display circuit 42 has an indicator light 44, and a control output driver circuit 38 has a transistor 45. Further, the transistor 46 is connected to the failure prediction output driver circuit 41, respectively.

The power source 47 is connected between the terminal a and the ground G, the load 48 is connected between the terminals a and b, and the load 49 is connected between the terminals a and c.

〔The invention's effect〕

Since the present invention uses an optical contact, that is, an optical switching element instead of the mechanical contact as the internal switch as described above, it causes contact welding, breakage of the movable contact plate, dust, etc., like the snap action switch. There is no risk of contact failure due to adhesion to the contacts.

Further, the present invention obtains a switch output from one optical sensor while the output of two optical sensors is present, and a diagnostic output from the other optical sensor. When one optical sensor fails, the other optical sensor is diagnosed. Since the output is changed to the switch output, the switch output can be secured continuously.

In the process of moving the actuator from the first position to the second position, when one optical sensor operates and the other optical sensor does not operate, a defect in the operating position of the actuator can be detected. If the set position is displaced due to loosening of the screw or the like during use of the switch, it can be known before the output of the switch is lost.

Moreover, since the return failure of the movable part is detected by measuring the return time difference between both sensors, when the movement of the movable part begins to become slower than the set value, that is, before the complete return failure occurs. You can know the condition.

[Brief description of drawings]

FIG. 1 is a front view showing a switch according to the present invention with a cover removed, FIG. 2 is a side sectional view, FIG. 3 is an enlarged front view of a built-in switch, FIG. 4 is an exploded perspective view of the built-in switch, and FIG. Is a front view showing the operating state of the built-in switch, FIG. 6 is a waveform diagram showing the output state of the built-in switch, and FIG. 7 is a block circuit diagram. 1 ... Housing, 3 ... Head, 4 ... Rotation axis, 5 ...
… Operator, 6 …… Roller, 7 …… Cam part, 8 …… Cap plunger, 9 …… Spring, 11 …… Internal plunger, 12 …… Diaphragm seal, 13 …… Built-in switch, 14 …… Case, 15 …… Operator, 17 …… Plunger, 18 …… Seal member, 19 …… Spring, 21 …… Actuating lever, 22 …… Pin, 23 …… Optical sensor, 25 …… Emitting element, 26 …… Receiving light Element, 27 …… Transparent window, 28 …… Transparent window, 29
... cover, 30 ... electronic circuit board, 31 ... cover, 34 ...
… CPU, 35 …… Driver circuit, 36 …… Light receiving circuit, 37…
… Constant voltage circuit, 38 …… Control output driver circuit, 39 ……
Control output display circuit, 40 ... Output transistor control circuit,
41 …… Failure prediction output driver circuit, 42 …… Failure prediction display circuit, 43 …… Indicator lamp, 44 …… Indicator lamp, 45 …… Transistor, 46 …… Transistor, 47 …… Power supply, 48 …… Load,
49 …… Load.

Claims (4)

[Claims] 1. An operator (5) driven by an external force is supported so as to move relative to a housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
And two optical sensors are housed in the optical sensor so that the light projecting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). A pair of translucent windows (27) (28), which are arranged at a predetermined interval, and which further selectively guide light from the respective light projecting elements to the respective light receiving elements in the actuator (15). Are spaced apart from each other in the direction of movement thereof, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) is moved, the operation start time of one optical sensor is There is a positional relationship such that the return time of the other optical sensor is earlier than the start time of the operation and the return time of the other optical sensor is earlier than the return time of the one optical sensor, and the actuator (15) is from the first position. In the process of reciprocating between the second positions Then, the operation output of the switch is obtained by the one optical sensor that operates first, and in the process of the actuator (15) returning from the second position to the first position, the one optical sensor that returns later switches the switch. In the process of reciprocating the actuator (15) between the first position and the second position while the output of both the optical sensors (23) is being output, When the switch output is obtained and the output of the other optical sensor is output, but the output of the switch of one optical sensor does not appear, it is determined that the one optical sensor whose output does not appear is a failure. A switch with a failure prediction function that changes the output of the other optical sensor that continues to operate from the next output to the switch output. 2. An operator (5) driven by an external force is supported so as to move relative to the housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
And two optical sensors are housed in the optical sensor so that the light projecting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). A pair of translucent windows (27) (28), which are arranged at a predetermined interval, and which further selectively guide light from the respective light projecting elements to the respective light receiving elements in the actuator (15). Are spaced apart from each other in the direction of movement thereof, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) is moved, the operation start time of one optical sensor is There is a positional relationship such that the return time of the other optical sensor is earlier than the start time of the movement and the return time of the other optical sensor is earlier than the return time of the one optical sensor, and the actuator (15) is moved from the first position. In the process of reciprocating between the second positions Then, the operation output of the switch is obtained by the one optical sensor that operates first, and in the process of the actuator (15) returning from the second position to the first position, the one optical sensor that returns later switches the switch. In the process of reciprocating the actuator (15) between the first position and the second position while obtaining the return output of, when one optical sensor operates and the other optical sensor does not operate, Detecting a defect in the operating position of the actuator (15), and when the output of one optical sensor disappears even though there is an output of the other optical sensor, this output no longer appears. A switch with a failure prediction function, which is characterized by determining that the optical sensor of the above is a failure and changing the output of the other optical sensor which continues to operate from the next output to the switch output. 3. An operator (5) driven by an external force is supported so as to move relative to the housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
And two optical sensors are housed in the optical sensor so that the light projecting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). A pair of translucent windows (27) (28), which are arranged at a predetermined interval, and which further selectively guide light from the respective light projecting elements to the respective light receiving elements in the actuator (15). Are spaced apart from each other in the direction of movement thereof, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) is moved, the operation start time of one optical sensor is There is a positional relationship such that the return time of the other optical sensor is earlier than the start time of the operation and the return time of the other optical sensor is earlier than the return time of the one optical sensor, and the actuator (15) is from the first position. In the process of reciprocating between the second positions Then, the operation output of the switch is obtained by the one optical sensor that operates first, and in the process of the operation element (15) returning from the second position to the first position, the one optical sensor returning later switches the switch. Of the return error of the movable part by measuring the return time difference between the two optical sensors (23) when the actuator (15) returns from the second position to the first position. Also, when the switch output of one optical sensor disappears even though the output of the other optical sensor does not appear, it is judged that one optical sensor whose output has stopped appearing as a failure and operation continues. A switch with a failure prediction function that changes the output of the other optical sensor from the next output to the switch output. 4. An operator (5) driven by an external force is supported so as to move relative to the housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
And two optical sensors are housed in the optical sensor so that the light projecting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). A pair of translucent windows (27) (28), which are arranged at a predetermined interval, and which further selectively guide light from the respective light projecting elements to the respective light receiving elements in the actuator (15). Are spaced apart from each other in the direction of movement thereof, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) is moved, the operation start time of one optical sensor is There is a positional relationship such that the return time of the other optical sensor is earlier than the start time of the operation and the return time of the other optical sensor is earlier than the return time of the one optical sensor, and the actuator (15) is from the first position. In the process of reciprocating between the second positions Then, the operation output of the switch is obtained by the one optical sensor that operates first, and in the process of the actuator (15) returning from the second position to the first position, the one optical sensor that returns later switches the switch. In the process of reciprocating the actuator (15) between the first position and the second position while obtaining the return output of, when one optical sensor operates and the other optical sensor does not operate, A defect in the operating position of the operator (15) is detected, and the operator (15) moves from the second position to the first position.
Detecting the return failure of the movable part by measuring the return time difference of both the optical sensors (23) when returning to the position of, and the output of the other optical sensor despite the output of the other optical sensor. When the switch output does not appear, it is judged that one of the optical sensors where this output does not appear is a failure, and the output of the other optical sensor that continues to operate is changed from the next output to the switch output. A switch with a characteristic failure prediction function.