JPH083456B2 - Switch with failure prediction function - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a switch capable of knowing a failure state in advance, and is particularly suitable for a switch that focuses on recovery failure.

[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 chips adhere to the operation plunger and the roller. There is a risk that the lever and the movable part including these may cause a return failure.

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]

SUMMARY OF THE INVENTION In view of such conventional problems, the present invention aims to improve various drawbacks of a built-in switch, especially a snap-action switch, and to detect in advance a return failure in a movable part such as an operation plunger and a lever of the switch. It is what

[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, and the operation output is obtained by the optical sensor that operates later and the return output is obtained by the optical sensor that returns later, and the difference in the return time of both optical sensors is measured. By doing so, it is possible to predict the return failure of the movable part.

〔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. Then, in both of the optical sensors 23a and 23b, 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. Is installed in.

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 1 is covered with a 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 the amount of direct change of the internal plunger 11, and the operator 15 is 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. At this time, as shown at time t ₁ in FIG. 6, the first optical sensor 23a is turned on, but the operation output as the switch is not output.

Further, when the operating element 5 reaches a sufficient operation amount, that is, a predetermined rotation amount, the operating element 15 reaches the position shown in FIG. 5C, and the second light transmitting window 28 allows the second optical sensor 23b and the light projecting element. The light emitted from 25 reaches the light receiving element 26, and the optical sensor 23b in FIG. 2 is turned on as shown at time t ₂ in FIG. 6 to generate an operation output as a switch. In this state both optical sensors
23a and 23b are operating.

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. Block light that actuator 15 leading to the light-receiving element 26 from the light projecting element 25 of the second optical sensor 23b at time t ₃ of FIG. 6 as opposed to by connexion prior thereto. That is, the second optical sensor 23b is restored and its output signal is turned off, but the return output of the switch is not output. At this point in time, a timer counter for poor 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 turned off. As a result, the return output of the switch is output. At this 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.

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

Further, the defective return of the movable parts such as the operating element 5, that is, the lever, the rotary shaft 4, the cup plunger 8, the internal plunger 11, the operating lever 21 or the operating element 15 is detected by the count number from the output point of the optical sensor which is returned later. It

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.

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 fixing pressure 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, according to the present invention, the two optical sensors and the two translucent windows are arranged in a positional relationship such 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 later. Since the operation output is obtained by the operating optical sensor, and the return output is obtained by the optical sensor that returns later, the return failure of the movable part can be easily detected by measuring the return time difference between both sensors. In particular, when the movement of the movable part starts to become slower than the set value, the restoration failure can be predicted before the complete restoration failure.

[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, 41 ... Failure prediction output driver circuit, 42 ... Failure prediction display circuit, 43 ... Indicator light, 44 ... Indicator light, 45 ... Transistor, 46 ... Transistor, 47 ...
Power supply, 48 ... load, 49 ... load.

Claims (1)

[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 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 differs from the starting time of the operation, and an operation output is obtained by an optical sensor that operates later, and The actuator (15) moves from the second position to the In the process of moving to the position of 1, the return output is obtained by the optical sensor that returns later, and the return of both the optical sensors (23) when the actuator (15) returns from the second position to the first position. A switch with a failure prediction function, which detects a return failure of a movable part by measuring a time difference.