JPH083453B2 - 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 or the cutting oil. There is a possibility that the roller lever and the movable portion including them may cause a return failure, or overtravel, that is, a shortage of movement after operation, or a roller lever type may cause a malfunction or 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, and uses an optical sensor, which is arranged along the moving direction of an actuator that optically opens and closes the optical sensor. Two sets are provided, one of which outputs an operation output in a light-entering state and the other of which outputs an operation output in a light-shielding state.
Further, when the two light sensors are incident, diagnostic light is provided separately from the light for obtaining the operation output, thereby detecting the deterioration state of the light sensor in both the non-operation state and the operation state of the actuator.

〔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, a first optical sensor 23a and a second optical sensor 23b are accommodated in the case 14. 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. When the operator 15 is moving, one of the both light-transmissive windows and the two light sensors 23a and 23b is at the start time of the operation of the first light sensor 23a and the other time is at the start time of the operation of the second light sensor 23b. They have the same positional relationship, and when one optical sensor 23a is in the light-entering state, the other optical sensor 23b is in the light-shielding state. And one optical sensor 23
The a is set to output an operation output when it is in the light entering state, and the other optical sensor outputs an operation output when it is in the light blocking state.

In addition, from the light emitting element 25 of the optical sensors 23a and 23b to the light receiving element 26
Modulated pulsed light is used as the light projected on.

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.

Now, in FIG. 1, when the operator 5, that is, the lever is rotated from the free state about the rotary shaft 4, its rotation amount is changed into a direct change amount of the internal plunger 11, and further the actuator 15 is operated via the lever. Is pressed. Therefore, when the operator is in the free position, the light emitted from the light projecting element 25 of the first photosensor 23a is blocked by the operator 15 and does not reach the light receiving element 26 as shown in FIG. However, the light emitted from the light projecting element 25 of the second optical sensor 23b reaches the light receiving element 26 through the second light transmitting window 28.

Next, when the actuator 15 reaches the position shown in FIG. 5 (b) in the process of moving from the free position, that is, the first position to the operating position direction, that is, the second position against the spring 19, the first light The light emitted from the light projecting element 25 of the sensor 23a reaches the light receiving element 26 through the first light transmitting window 27. On the contrary, the light emitted from the light projecting element 25 of the second optical sensor 23b is the actuator 15
It is blocked by and does not reach the light receiving element 26. At this time, as shown at the time point t ₁ in FIG. 6, operation outputs are output from both the optical sensors 23a and 23b.

When the operating element 5 reaches a sufficient amount of movement, that is, overtravel, the operating element 15 reaches the second position, and the state shown in FIG. That is, the first optical sensor 23
The light a is in the light entering state, and the second light sensor 23b is in the light blocking state.

Then, when the operating element 5 is in the fully 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 moves to the spring 9 and the cup plunger 8.
Will start to return to the original position. At the same time, the actuator 15 is the fifth
As shown in the figure (b), the urging force of the spring 19 starts the movement from the second position, that is, the operating position, toward the first position, that is, the free position. When the movement progresses further, the sixth
At t ₃ in FIG, block light reaching to the light receiving element 26 from the light projecting element 25 of the first optical sensor 23a as shown in FIG. 5 (b). At the same time, the light emitted from the light projecting element 25 of the second optical sensor 23b reaches the light receiving element 26 through the second light transmitting window 28.
That is, in this state, both optical sensors 23a and 23b are restored.

Further, in the light entering state of both the optical sensors 23a, 23b to the respective light receiving elements 26 from the respective light projecting elements 25 through the cut-off windows 27, 28 of the operator 15, to obtain the operation output of the switch, that is, light of the same waveform, that is, Modulated light L1 is emitted, and in the light entering state of both optical sensors 23a and 23b, from the respective light projecting elements 25 to the respective light receiving elements 26 through the light shielding windows 27 and 28 of the operator 15, separately from the pulse modulated light L1. , Pulse-modulated diagnostic light L ₂ is supplied. That is, pulse-modulated light
L1 and diagnostic light L2 are emitted from each of the optical sensors 23a and 23b. The diagnostic light is set to a value smaller than the light for obtaining the operation output of the switch, or the diagnostic light is set to a value smaller than the pulse number of the modulated light for obtaining the operation output of the optical sensor.

Modulated light for obtaining the operation output of the optical sensor from FIG.
The relationship between L ₁ and modulated light L ₂ for diagnosis is shown. In this figure, the modulated light to obtain the operation output of the optical sensor
L ₁ has a plurality of pulses, for example, 20 between the times t ₁ and t _2.
After the light is emitted, one diagnostic light L ₂ is emitted at time t ₂ . Similarly, from the time t ₄ to the time t ₅ , a plurality of modulated lights L ₁ for obtaining the operation output of the switch are emitted, then at the time t ₅ , one diagnostic light L ₂ is emitted, and at the time t ₆ , the optical sensor. Output is turned off.

Therefore, when the actuator 15 is at the free position, that is, the first position, the diagnostic light L ₂ is emitted from the light projecting element 2 of the second optical sensor 23b.
The light is projected onto the light receiving element 26 from 5. At this time, the light emitting element 2
If the level of the diagnostic light L2 falls below a predetermined level for some reason such as deterioration of the light receiving element 26 or the surface of these elements, or contamination of the surface of these elements, the lowering level of the light received by the light receiving element 26 decreases. Thus, the deterioration state of the second optical sensor 23b is detected.

Further, when the operator 15 is in the operating position, that is, the second position, the diagnostic light L ₂ is projected from the light projecting element 25 of the first optical sensor 23a to the light receiving element 26 thereof, so in this state the first optical sensor The deterioration state of 23a is detected.

When the actuator 15 is in the second position, the modulated light L ₁ for obtaining the operation output of the switch is also projected on the light receiving element 26 together with the diagnostic light L _{2 in} the time relationship shown in FIG.

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 above-mentioned optical sensor 23 is transparent to the optical sensors 23a and 23b so that the first optical sensor 23a outputs an operation output as a switch when the first optical sensor 23a is in the light-shielded state, and the second optical sensor 23b outputs the output when the light is in the incident state. A relative positional relationship with the light windows 27 and 28 can be set, and in this case, the operation is substantially the same as that of the above-described embodiment.

Further, although the roller lever type is shown as the manipulator 5, an ordinary lever having no roller may be used, and in the case of the plunger type, an external plunger may be used.

〔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 operation output is obtained when one light sensor is in the light entering state and the other light sensor is in the light blocking state, and the light for obtaining the operation output when each of the light sensors receives light is Since the diagnostic light is separately provided, the deterioration state of the other optical sensor is diagnosed when the actuator is in the first position, and the deterioration state of one optical sensor is diagnosed when the actuator is in the second position. Therefore, the failure of the optical sensor can be predicted before the operating output of the optical sensor completely disappears.

[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 operation state of the built-in switch, FIG. 6 is a waveform diagram showing the relationship between the operation output of the optical sensor and pulse-modulated light, 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 (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 provided apart from each other in the direction of movement thereof, and both of these light-transmitting windows and the both optical sensors (23) are mainly arranged such that when one optical sensor is in a light-entering state, the other optical sensor is in a light-shielding state. In addition, each light sensor has a smaller amount of light or a smaller number of pulses than the pulsed light and the pulsed light for obtaining an operation output from the light emitting element to the light receiving element when light is incident. Alternately give diagnostic light of value, Each optical sensor (23) judges that the optical sensor (23) in the light entering state is normal when the diagnostic light is above a predetermined level, and when the judgment light is lower than the predetermined level. , The light sensor (23) in the light receiving state is judged to be deteriorated, and the above-mentioned actuator (15)
Is diagnosing the deterioration state of the other optical sensor when is in the first position, and is diagnosing the deterioration state of one of the optical sensors when the actuator (15) is in the second position. Switch with failure prediction function.