JPH083458B2 - 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]

2. Description of the Related Art Conventionally, there are a plunger type limit switch having a snap action switch incorporated in a housing and having an operating plunger protruding to the outside of the housing, and a roller lever type limit switch for converting a rotational movement of a 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 possibility that the lever and the movable portion including them may cause a return failure, overtravel, that is, a shortage of movement after the operation, or in the roller lever type, an operation failure or 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 improves various drawbacks of a built-in switch, especially a snap-action switch, and when one of the switch elements fails, the failure is determined and the switch output is The purpose is to continue to secure.

[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 of optical sensors are provided, and while the outputs from these two sets of optical sensors are present, an operation output is obtained by an optical sensor that operates later, and a return output is obtained by an optical sensor that returns later. When the output of No. 1 is lost, one of the optical sensors is judged to be in failure, and the other optical sensor is used instead to continue the switch output.

〔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 and 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 when the actuator 15 is moved. Have And in this embodiment, the actuator
When 15 moves from the first position to the second position, it works before the second optical sensor 23b, but at this time, the operation output as the switch is not output. 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, it is set to output a return output as a switch.

On the other hand, it operates after the operation of the first optical sensor 23a, and at this time point, an operation output as a switch is output. Further, the second optical sensor is set so as to output a diagnostic output before the first optical sensor 23a outputs a switch return output.

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.

When the operating element 5, that is, the lever rotates from the free state about the rotary shaft 4 in the above-mentioned configuration, the amount of rotation thereof is changed into a linear change amount 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, in the process in which the actuator 15 moves from the free position toward the operating position against the spring 19, when it reaches the position shown in FIG. 5B, the first light transmitting window 27 causes the first light to pass through. The light emitted from the light projecting element 25 of the sensor 23a reaches the light receiving element 26 thereof. First optical sensor 23a, as shown at time t ₁ of FIG. 6 at this time to operate.

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 signal, and the operation output as a switch is output. 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 on the operating element 5 is removed, and this operation is returned to its original position by the spring 9 and the cup plunger 8. Start returning. 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 is restored, and at this time, a timer counter for restoration failure (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 is restored. As a result, a return output as a switch is output, and 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 again moves from the first position to the second position, and when the time point t ₅ in FIG. 6 is reached, the first optical sensor 23
Although a is operated, as actuator 15 continues to move, the second optical sensor 23b when it reaches the time point t ₆ in FIG does not issue a diagnostic output, connexion by the this second optical sensor 23b
Is judged to have 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.
Not of course return signal of the second optical sensor 23b in the further actuator 15 moves and reaches the point t ₈ of the drawing, the first optical sensor 23a issues a return output. Further, the actuator 15 returns to the first position as it is.

Hereinafter, there is no signal from the second optical sensor 23b, that is, a diagnostic output, and only the switch output by the first optical sensor 23a is output, and only this output is continuously output.

Also when the first optical sensor 23a and second light sensor 23b is operating together properly, the first optical sensor fails, the signal at time t ₁₅ of FIG. 6 is a Natsuta not appear, signal is issued from the second optical sensor 23b at time t _16,
This signal determines that the first optical sensor 23a has failed. At the same time, this fault condition is displayed externally. Then the second optical sensor 23b is restored at time t ₁₇ in the figure, the first optical sensor 23a is reached at time t ₁₈ will not issue a return output to have failed, actuator 15 as it is Return to the first position.

Further, when the operator 15 moves from the first position toward the second position and reaches the time point t ₁₉ in FIG. 6, the first optical sensor 23a does not output the operation output as at the time point t ₁₅ .

And further moves actuator 15, but upon reaching the time point t ₂₀ of FIG. 6 second optical sensor 23b issues an output, rather than diagnostic output from this point, namely the operation output of Daitsute switch to 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, at the time t ₂₁ of FIG. 6 to return a second light sensor 23b is, 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 sensor 23b obtains the diagnostic output, when the output of one of the optical sensors is exhausted, the other optical sensor continues the switch output.

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, according to the present invention, while the actuator 15 reciprocates between the first and second positions, while one optical sensor outputs the switch output while the other optical sensor outputs, the other optical sensor diagnoses. Although the output is obtained, the switch operation is not interrupted because the switch output is continued by the other optical sensor when the output of one of the optical sensors is exhausted.

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

[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 (2)

[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). Also, an operator (15) which is interlocked with the operator (5) is reciprocally supported between a first position and a second position, and has a predetermined interval in the housing (1). With a light emitting element (2
5) and the light receiving element (26)
3), two of these optical sensors are arranged so that the light emitting element and the light receiving element are optically separated by the actuator (15) and in the moving direction of the actuator (15). Arrange them at a certain interval,
Further, the actuator (15) is provided with a pair of translucent windows (27) (28) which selectively guide light from the respective light projecting elements to the respective light receiving elements and are spaced apart from each other in the moving direction. The two translucent windows and the both optical sensors (23) are arranged such that the operation start time of one optical sensor is earlier than the operation start time of the other optical sensor when the actuator (15) is moved, and the other. Has a positional relationship such that the return time of the optical sensor is earlier than the return time of one optical sensor, and the actuator (15) reciprocates between the first position and the second position. In the process, the operation output of the switch is obtained by the other optical sensor that operates later, and in the process that the actuator (15) returns from the second position to the first position, the one optical sensor that returns later switches the switch. And get the return output of In the process in which the actuator (15) reciprocates between the first position and the second position, while the outputs of both the optical sensors (23) are present, the other optical sensor that operates later outputs the switch output. This output is obtained when the output of one of the optical sensors returns and the output of one of the optical sensors disappears, but the switch output of the other optical sensor ceases to appear. A switch with a failure prediction function, which determines that the optical sensor that has stopped appearing is a failure and changes the output of the 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). Also, an operator (15) which is interlocked with the operator (5) is reciprocally supported between a first position and a second position, and has a predetermined interval in the housing (1). With a light emitting element (2
5) and the light receiving element (26)
3), two of these optical sensors are arranged so that the light emitting element and the light receiving element are optically separated by the actuator (15) and in the moving direction of the actuator (15). Arrange them at a certain interval,
Further, the actuator (15) is provided with a pair of translucent windows (27) (28) which selectively guide light from the respective light projecting elements to the respective light receiving elements and are spaced apart from each other in the moving direction. The two translucent windows and the both optical sensors (23) are arranged such that the operation start time of one optical sensor is earlier than the operation start time of the other optical sensor when the actuator (15) is moved, and the other. Has a positional relationship such that the return time of the optical sensor is earlier than the return time of one optical sensor, and the actuator (15) reciprocates between the first position and the second position. In the process, the operation output of the switch is obtained by the other optical sensor that operates later, and in the process that the actuator (15) returns from the second position to the first position, the one optical sensor that returns later switches the switch. Return output of If the output of the other optical sensor disappears even though there is an output of one optical sensor, it is judged that the optical sensor whose output does not appear is a failure, and the operation is continued. A switch with a failure prediction function that changes the output of the existing optical sensor from the next output to the switch output.