JPH083454B2 - 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 rotary shaft supporting the roller lever and the head, and the cutting oil solidifies or chips adhere to the operation plunger. Otherwise, the roller lever and the movable part including them may cause a return failure, or overtravel, that is, insufficient movement after operation, or in the roller lever type, operation failure or setting failure due to roller wear.

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 uses an optical sensor in place of the snap-action switch in the switch built in the housing, and the optical sensor is arranged along the moving direction of the actuator that optically opens and closes the switch. Two sets of optical sensors are provided, and the operation output is obtained by the optical sensor that operates first and the return output is obtained by the optical sensor that returns later, and the operating element is determined from the operating state of both optical sensors. Of the setting error, or by measuring the difference between the return times of both optical sensors, the return failure of the movable part is predicted.

〔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.
Rotatably supported by its free end abutting the plunger 17 and its middle part 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, 23a and 23b in the case 14
Is housed. This optical sensor is composed of a light projecting element 25 and a light receiving element 26 which are optically opposed to each other, 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, a pair of translucent windows 27, 28 for selectively guiding the light from the light projecting element 25 of the optical sensors 23a, 23b to the light receiving element 26 are provided in the actuator 15 in the moving direction thereof, that is, the thin core wire of the case 14. They are spaced apart from each other in the 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

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 is covered with the cover 31.

In the above structure, when the operator 5, that is, the lever rotates from the free state about the rotary shaft 4, the amount of rotation thereof is changed to a direct change amount of the internal plunger 11, and the operator 15 is pressed through the lever. It 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 photosensors 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 operation element 5 reaches a sufficient operation amount, that is, a predetermined rotation amount, the operation element 15 reaches the position shown in FIG. 5C, and the second light transmitting window 28 allows the light projecting element of the second optical sensor 23b. The light emitted from 25 reaches the light receiving element 26, and the second optical sensor 23b emits a signal as shown at time t ₂ in FIG. 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. As actuator 16 opposite to the by connexion before it blocks the light that reaches 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. In this state, the output signal of the switch is on. At the same time, a timer counter for defective recovery (not shown) starts counting at this point.

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 is restored. As a result, the output signal of the switch is turned off. 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.

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

That is, as the output signal of the switch, of the two optical sensors, the first optical sensor 23a obtains the operation output and the return output as the switch, and the second optical sensor 23b obtains the failure detection signal. That is, the operation output is obtained at time t ₁ in FIG. 6 and the return output is obtained at time t ₄ in FIG.

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 restoration of the movable portion such as the operating element 5, that is, the lever or the rotary shaft 4, the cup plunger 8, the internal plunger 11, the operating lever 21 or the operating element 15 is caused by the output time of the optical sensor which has been restored first, that is, the second optical sensor. It is detected by the number of counts from.

The optical sensor 23 described above can set the relative positional relationship between the optical sensors 23a and 23b and the translucent windows 27 and 28 so that the second optical sensor 23b operates first. Is substantially the same as the embodiment described above.

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. And this CPU has a driver circuit 35, 35 for driving the light emitting elements 25, 25 and a light receiving element.
Light receiving circuits 36, 36 for converting the optical signals from 26, 26 into electric signals are connected, respectively. Further, the CPU 34 includes a fixing pressure circuit 37, a control output driver circuit 38, a control output display circuit 39, an output transistor diagnostic circuit 40, and a failure prediction output driver circuit 4
1, the failure prediction display circuit 42 and the like are connected, the control output display circuit 39 further has an indicator light 43, the failure prediction display circuit 42 has an indicator light 44, and the 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, according to the present invention, the two optical sensors and the two light-transmitting windows are arranged in such a positional relationship that the operation start time of one optical sensor and the operation start time of the other optical sensor are different from each other, and Since the one optical sensor is used for the operation output of the switch and the second optical sensor is used for detecting the failure signal, that is, both optical sensors have independent functions, so that the operating positions of both optical sensors are The deviation can be set to be large. Therefore, the sensitivity in failure prediction detection can be increased.

In addition, since the operating status of both optical sensors is detected to detect the setting error of the operating element, if the setting position shifts due to loosening of the screw etc. while using the switch, the switch output can be obtained. You can know before it runs out.

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 (3)

[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 moving to the second position, One of the operating optical sensors obtains the operation output of the switch, and in the process of the actuator (15) returning from the second position to the first position, the optical sensor returning later obtains the switch return output. In the process in which the actuator (15) moves from the first position to the second position, when one of the photosensors operates first and then the other photosensor does not operate, the manipulator (5) A switch with a failure prediction function, which detects a defect in the operating position of the switch. 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 moving direction, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) moves, one of the optical sensors starts operating and the other optical sensor has In the process of moving the actuator (15) from the first position to the second position, there is a positional relationship that is different from the operation start time, and the operation output of the switch is changed by the optical sensor that operates first. , The actuator (15) is the second In the process of returning from the first position to the first position, the optical sensor returning later obtains the return output of the switch, and both the optical sensors when the actuator (15) returns from the second position to the first position. (23) A switch with a failure prediction function characterized by detecting a failure in the recovery of the movable part by measuring the recovery time difference. 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 moving direction, and both the translucent windows and the both optical sensors (23) are arranged such that when one of the optical sensors (15) moves, one of the optical sensors starts operating and the other of the optical sensors. In the process of moving the actuator (15) from the first position to the second position, there is a positional relationship that is different from the operation start time, and the operation output of the switch is changed by the optical sensor that operates first. And the actuator (15) is the first In the process of moving from the position toward the second position, first, when one optical sensor operates and then the other optical sensor does not operate, a defect in the operating position of the operator (5) is detected and In the process of returning the actuator (15) from the second position to the first position, a return output of the switch is obtained by an optical sensor that returns later, and the actuator (15) further moves from the second position to the first position. A switch with a failure prediction function, characterized by detecting a return failure of a movable part by measuring a return time difference between the both optical sensors (23) when returning to a position.