JPH08203370A - Safety switch device - Google Patents

Abstract

PURPOSE: To provide a safety switch device which can surely keep a door or the like from opening unless a high-temperature portion is cooled while industrial machinery or the like is in a complete stopped state. CONSTITUTION: This safety switch device comprises a switching actuator 4 mounted on a door D, etc., and a main body portion 1 secured into place in such a way that the switching actuator 4 is drawn into and out of it by the opening and closing of the door D, etc. The main body portion 1 is provided with a safety switch S1 which is switched so that main circuits P3, P4 for supplying power to machines, etc., are turned on and off by the drawing in and out of the switching actuator 4; a lock mechanism that locks the inserted switching actuator 4 automatically and mechanically to prevent the actuator 4 from being drawn out; and a solenoid 34 for unlocking the lock mechanism. The device is also provided with a timer TM which is actuated by the input of an off detection signal at the detection of the cutoff of the supply of power to the machines, etc., to measure a certain period of time and a timer switch S3 which is inserted into and connected to the power supply circuits P5, P6 of the solenoid 34 and turned on when the timer TM has measured the period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the operation of an internal machine when a door for a doorway of a room or factory in which an industrial machine is installed or a protective door provided in a danger zone of the industrial machine itself is opened. Automatically stop the machine and prevent the machine from operating unless the doors and protective doors are completely closed to prevent the human body from being caught in an industrial machine. The present invention relates to a safety switch device.

[0002]

2. Description of the Related Art Conventionally, for example, in Europe, maintenance work for industrial machines has been used as a means for preventing accidents caused by a third person accidentally turning on power during maintenance work on industrial machines. Prior to the procedure, a worker must remove all fuses from the fuse-type blade switch and put them in their pockets before starting work.In the United States, maintenance workers should not turn on the power after shutting it off. It is locked with a key, and the management method for ensuring the safety of such maintenance work is legally required. However, with such a management method that relies on the awareness of the worker himself, there is a risk that the worker will forget it and lose its effect.

Therefore, in the case where a dangerous industrial machine which is liable to be caught or damaged by a human body is installed, the door of a doorway of a room or factory where the machine is installed or the industrial machine is installed. By installing a safety switch device that automatically detects the opening and closing of the protective door and turns it on and off, it is prohibited to enter a hazardous area, or an internal installation as long as a human body exists in a room or factory. It is advisable to prohibit operation of the machine or to prevent it from operating unless the protective door is closed.

As a conventional safety switch device used for such an application, when a door is closed, a switching actuator attached to the door is inserted into a switch main body portion to switch the switch portion, whereby The power supply circuit to the installed industrial machine is closed to enable the industrial machine to operate, and the lock mechanism automatically locks the switching actuator, that is, mechanically locks the door so that it cannot be opened. It is like this. on the other hand,
When the power supply to the industrial machine is cut off, the programmable controller circuit controls the power supply to the solenoid by the operation off detection signal, the solenoid is excited and the lock mechanism releases the lock, and the door can be opened. It is configured to be in a state.

[0005]

By the way, in many cases, when the lock by the above-mentioned lock mechanism is released, the fact that the door can be opened is displayed outside by the lighting of the indicator lamp or the like. . When the door is opened after checking the display, the switching actuator is removed from the switch body and the switch is switched, opening the power supply circuit to industrial machinery and making the machine inoperable. Maintained. However, industrial machinery, etc.
Even if the power supply is cut off, the operation cannot be stopped immediately, and the operation continues for a while due to its own inertial force. Therefore, if the door is immediately opened to enter the inside by checking the above-mentioned display, there is a problem that a very dangerous situation occurs. Further, in an industrial machine in which heat is received during operation to raise the temperature of the housing and the like, it takes a considerable amount of time to cool the hot portion even if the operation is stopped. In such an industrial machine, even if the door is opened in a state where the operation is completely stopped, there is a risk of touching a hot part and getting burned.

Further, due to a programming error of the programmable controller or some abnormality, a signal for exciting the solenoid may be erroneously input even though the operation-off detection signal is not output. In such a case, even though the industrial machine is operating, the lock by the lock mechanism is released and the door can be opened,
Moreover, the state is displayed on the indicator light. In such a case, if the door is unintentionally opened by relying only on the indication that the door can be opened by the indicator light, a serious accident may occur.

Therefore, an object of the present invention is to provide a safety switch device capable of surely prohibiting the opening of a door or the like unless an industrial machine or the like is in a completely stopped state or a hot place is cooled. It is what

[0008]

A safety switch device according to claim 1 of the present invention, which is proposed to achieve the above object, comprises a switching actuator attached to a movable member such as a door and an opening / closing of the door. The switching actuator is fixedly inserted and removed, and a main circuit for supplying power to a machine or the like is closed or opened by inserting or removing the switching actuator into or from the main body. A safety switch that can be switched,
Includes a lock mechanism that automatically and mechanically locks the inserted switching actuator to prevent it from being pulled out, and a lock release solenoid for this lock mechanism. There is provided a timer that is activated by the input of the operation-off detection signal and that measures a certain time, and a timer switch that is connected to the solenoid power supply circuit and that is turned on when the timer times out.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the safety switch device of the present invention further includes a display section for displaying the ON state of the timer switch and a power supply circuit for the solenoid. A push button switch that is inserted and connected and that is turned on by a pressing operation is provided.

[0010]

According to the safety switch device of the first aspect, when the door to which the switching actuator is attached is opened, the safety switch opens the main circuit for supplying power to the machine or the like. , The machine is kept inoperable. Next, when the door is closed, the switching actuator is inserted into the main body portion to switch the safety switch, and the safety switch closes the main circuit for supplying power to the machine to put the machine in an operable state. At the same time, since the lock mechanism automatically and mechanically locks the switching actuator so as to prevent the switching actuator from being pulled out, opening of the door is surely prohibited during the operation of the industrial machine.

Next, when the power supply circuit is cut off by the operation of stopping the operation of the machine or the like, the operation-off detection signal that detects it is input to the timer, and the timer is activated to start the timekeeping operation for a fixed time. To do. When the timer finishes counting a certain amount of time, the timer switch is turned on and the power supply circuit of the solenoid is closed, the solenoid is excited and the lock by the lock mechanism is released, and the door can be opened only at this point. . Therefore, the time from the stop of power supply to the industrial machinery installed inside until it is completely stopped, or the temperature of the industrial machine that has been heated up due to the operation is stopped and the part that has reached high temperature is cooled. If you measure the time until it is set and set the measured time as the time measured by the timer, it will be locked by the locking mechanism unless the machine is completely stopped or the hot part does not cool. Is not released and the door can be opened when the machine is completely stopped or cooled. As a result, it is possible to reliably prevent accidents such as being caught in a machine that continues to operate due to inertial force, or being burned due to contact with a hot spot.

According to the safety switch device of the second aspect, the lock by the lock mechanism is not released unless the push button switch is pressed after confirming the display on the display unit. Therefore, even if the timer is mistakenly started and the time is up due to a programming error or some abnormality in the pluggable controller, the lock by the lock mechanism is not released at that point, and after confirming the display on the display unit, A confirmation operation for pressing the push button switch is required. Therefore, for example, by displaying a caution for operation in the vicinity of the push button switch, it is possible to detect the operation of the machine by the noise generated inside before the push operation of the push button switch. Therefore, it is possible to prevent the door from being inadvertently opened by relying on the display of the indicator lamp as in the conventional case.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. 1 to 4 are electric circuit diagrams in each state showing a safety switch device according to an embodiment of the present invention, and FIG. 5 is a timing chart thereof. 1 to 5 are the gist of the present invention,
In order to facilitate understanding of the present invention, first, FIGS.
The schematic configuration of the safety switch device of the present invention will be described below.

FIG. 6 shows a perspective view of the mounted state. In the figure, the safety switch device of the present invention comprises a main body portion in which a solenoid unit 2 is connected to one side portion of the switch main body unit 1. The main body portion and the switching actuator 4 attached to the door D are combined. Furthermore, the switch body unit 1
Is composed of a switch portion 1a and a passive operation portion 1b which is operated by inserting and removing the switching actuator 4 by opening and closing the door D to switch the switch portion 1a. Insertion holes 1c and 1d into which the switching actuator 4 is inserted when the door D is closed are formed in the lid of the passive operation portion 1b. In this embodiment, the switching actuator 4 can be arranged to be inserted and removed by selecting one of two directions orthogonal to the switch body unit 1.
It has two insertion holes 1c and 1d. The body portion is attached by screwing the attachment piece 2a of the solenoid unit 2.

Next, FIG. 7 showing a plan view of the switch main body unit 1 in a state where the lid is removed and FIG. 7 sequentially showing an operation process of inserting and removing the switching actuator 4 in the passive operating portion 1b of the switch main body unit 1. 8 (a) ~
(C) will be described. The switching actuator 4, which is attached to a movable body such as the door D separately from the main body portion fixed at a predetermined location, has a predetermined step on the tip surface thereof, and has two kinds of three operation pressing surfaces 4a, 4b. Further, an escape hole 4c for a cam-shaped plate, which will be described later, and a return pressing surface 4d formed of a hole edge surface of the escape 4c are integrally formed.

In FIG. 7, in the passive operation portion 1b, a driving cam-shaped plate 8 and a pair of regulating cam-shaped members located on both sides of the supporting shaft 7 spanned between a pair of support bases 6. The plate 9 and the plate 9 are rotatably mounted so as to be overlapped with each other and independently of each other. As shown in FIG. 8, each of the cam-shaped plates 8 and 9 has two notches of the same shape formed corresponding to each of the two insertion holes 1c and 1d. The pressure receiving portions 10 and 11 for operation are formed in the section, and the pressure receiving portions 12 and 13 for the return are formed in the other side portion, respectively. Further, the cam-shaped plates 8 and 9 are respectively formed with guide cam holes 15 and 16 through which the single cam follower pin 14 is inserted, and the cam end follower pins 14 at the start ends of the cam holes 15 and 16 are engaged. The locking holes 17 and 18 to be inserted are shown in FIG.
As clearly shown in (c), they are formed so as to communicate with each other in a protruding state, and the peripheral end portions in the vicinity of the guide cam holes 15 and 16 are cut out to form engagement step portions 19 and 20, respectively.

The lock lever 21 serves as a lock mechanism for automatically and mechanically locking the passive operating portion 1b in the switching state of the switch portion 1a when the switching actuator 4 is inserted. Above them, they are movably arranged in a state orthogonal to these. That is, the lock lever 21 is engaged with the base bar 22 located above the cam-shaped plates 8 and 9 and orthogonal thereto, and with the engagement step portions 19 and 20 of the cam-shaped plates 8 and 9, respectively. U-shaped locking rods 23 are integrally extended, and actuating pieces 24 are vertically provided from both ends of the base bar 22 so as to be positioned on both left and right sides of the passive operating portion 1b. .

Further, the lock lever 21 has its upper portions at both ends pressed and urged by the coil spring 25 from the front side, and the lower ends of the respective actuating pieces 24 are urged and pressed by the coil spring 26 from the rear side. 8A to 8C are always urged to rotate in the clockwise direction in FIGS. Is held. Further, the operating rod 27 protruding from the solenoid unit 2 attached to the side portion of the switch body unit 1 is inserted through the insertion hole (not shown) of the switch body unit 1 to the front side of the lower end portion of the one operation piece 24. Is abutted against.

The operation of the above configuration will be briefly described. Door D
When the switch actuator 4 is opened and the switching actuator 4 is removed from the switch body unit 1, the driving cam-shaped plate 8 and the regulating cam-shaped plate 9 are used for their respective actuations, as shown in FIG. 8A. A state in which the pressure receiving portions 12 and 13 are stationary with a rotational phase difference that substantially matches the steps of the corresponding pressing surfaces 4a and 4b of the switching actuator 4, and the guide cam holes 15 and 16 can guide the cam follower pin 14. Are polymerized in conformity with each other. Therefore, unless each cam-shaped plate 8 or 9 is rotated by the switching actuator 4 while maintaining the initial rotational phase difference, that is, even if a member other than the switching actuator 4 is inserted and operated, the cam follower pin 14 does not operate. The cam portions 8 and 9 are engaged with the locking holes 17 or 18 to prevent rotation of the cam-shaped plates 8 and 9, and
The switching operation of a is prevented.

Then, by the switching actuator 4 inserted into the switch body unit 1, each cam-shaped plate 8,
When 9 is rotated counterclockwise in FIGS. 8A to 8C, the cam follower pin 14 moves the guide cam hole 1 into the guide cam hole 1.
8A to 8C against the biasing force of the return spring 30 by being pushed rearward along 5 and 16 and being guided by the id portions 29 on both sides of the guide body 28. Is moved in the direction. When the cam follower pin 14 is moved to the position shown in FIG. 8B, both the switch changeover member 31 having the cam follower pin 14 fixed to the front end and the switch changeover body 32 connected thereto are rearward (upper side in FIG. 7). The safety switch S1 of the switch unit 1a, which will be described later, is switched from the normally closed contact to the normally open contact.

When the safety switch S1 is switched, the cam-shaped plates 8,
As shown in FIG. 8B, the locking rod 23 of the lock lever 21 slidably contacting the peripheral end surface of 9 engages with the engaging step portions 19 and 20, and the cam-shaped plates 8 and 9 are illustrated. Block the clockwise rotation at 8. Therefore, the switching actuator 4
Even if it tries to move in the pulling-out direction, that is, to open the door D, the return pressing surface 4d of the switching actuator 4 has the return pressure receiving surfaces 12 and 13 of the cam-shaped plates 8 and 9 in the rotation blocking state. To automatically and mechanically lock the safety switch S1 in the switching state in which the normally open contact is ON.

Next, when the solenoid of the solenoid unit 2 is suction-driven by the operation-off detection signal when the power supply to the machine is cut off, the operation rod 27 is operated in the direction of the arrow in FIG. 24 is pushed, the lock lever 21 is rotated counterclockwise, the lock is released, and the door D is opened.

Next, FIGS. 1 to 5, which is the subject matter of the present invention, will be described. 1 to 4, an auxiliary circuit port P to which a programmable controller or the like is connected
1 and P2, the normally-closed contact b of the safety switch S1 incorporated in the switch portion 1a of the switch body unit 1
1 are connected in series. The signal between the auxiliary circuit ports P1 and P2 is inverted and output by the inverter IV. In addition, a safety switch S is provided between the main circuit (safety circuit) ports P3 and P4 for controlling energization of a machine or the like.
One normally open contact a1 is connected in series.

A solenoid 34, an illuminated push button switch section 35, a timer circuit 36, and a power source indicator light 37 composed of an LED are connected in parallel between the solenoid power source ports P5 and P6. The illuminated push button switch 35 portion is configured by a push button switch S2 and a display portion DP including an LED. The timer circuit 36 is composed of a timer TM that counts a fixed time by inputting an operation-off signal that detects the interruption of power supply to a machine or the like, and a timer switch S3 that is turned on when the timer TM times out.
The timer TM indicates the time from the time when the power supply of the industrial machine installed internally is completely stopped to the time when the power supply is cut off, or the position where the temperature of the industrial machine is raised after the power supply is stopped due to the operation. A clocking time is set in advance, which measures the time until the cooling state is reached. Timer switch S3
Is returned to the off state by the non-excitation detection signal of the solenoid 34. Further, the solenoid 34 has a diode 38 for protection.

Next, the operation of the above embodiment will be described with reference to the timing chart of FIG. Door D opens and switching actuator 4 switches main unit 1
When the safety switch S1 is off, the normally open contact a1 of the safety switch S1 is in the off state and the main circuit ports P3 and P4 are open, so that power is supplied to the machine. The circuit is interrupted and the machine remains held in a non-operational state. That is, when the door D is open, the machine does not operate even if the operation switch or the like is turned on. In addition, the auxiliary circuit port P1,
Between P2, normally closed contact b1 of safety switch S1 in ON state
The circuit closed state by is inverted by the inverter IV and is open, and the control system of the machine is also cut off.

When the machine is operated, when the door D is closed as shown in FIG. 6, the safety switch S1 is switched by the switching actuator 4 inserted in the main body as shown in FIG. The contact a1 is turned on. As a result, the main circuit ports P3 and P4 are closed to make the machine operable, and the auxiliary circuit ports P1 and P2 are also closed to make the machine control system of the programmable controller operable. Become. At this time, as shown in FIG. 8B, the switching actuator 4 is locked by the lock mechanism so as not to be pulled out, and the door D is kept in a safe state in which the opening is prohibited.

Further, in order to stop the running machine,
When operated to stop the power supply to the machine, FIG. 5 (a)
As shown in FIG.
Input to M. As a result, the timer TM starts the clocking operation for the set fixed time T, as shown in FIG. At this time, the internally installed machine continues to operate due to inertial force. When this machine is in a complete stop state, or when the high temperature place is completely cooled,
2 and 5 when the timer TM times out.
As shown in (c), the timer switch S3 is turned on. At the same time, as shown in FIG. 5D, the display portion DP of the illuminated push button switch portion 35 is powered by the solenoid power source ports P5 and P6 through the on-state timer switch S3 and lights up, and the machine is completely turned on. In the stopped state,
In addition, the fact that the location where the temperature is high is cooled is notified.

After the operator confirms the notification on the display portion DP, as shown in FIGS. 3 and 5 (e), when the push button switch S2 is pressed and turned on, the timer switch S3 and the timer switch S3 both turned on. Power is supplied to the solenoid 34 from the solenoid power supply ports P5 and P6 through the push button switch S2, and the solenoid 34 is excited as shown in FIG. 5 (f) to lock the switching actuator 4 by the lock mechanism in FIG. The door D is released as shown in FIG. 3 and the door D becomes openable only at this point. FIG. 5 (c),
As shown in (f), the timer switch S3 returns to the off state when the solenoid 34 is de-energized. In this way, unless the machine installed inside is completely stopped, the lock mechanism will not release the lock, and when the machine is completely stopped or the hot part is completely cooled. For the first time, the door can be opened.
Therefore, it is possible to reliably prevent accidents such as being caught in a machine that continues to operate due to inertial force, or touching a high temperature location and causing burns.

In the above embodiment, the lock by the lock mechanism is not released unless the push button switch S2 is pressed after confirming the display on the display portion DP. Therefore, even if the timer TM is mistakenly started and the time is up due to a programming error of the pluggable controller or some abnormality, even if the internal machine is operating, the lock by the lock mechanism will still occur at that time. Since it is not released, it is possible to prevent the door D from being unintentionally opened by seeing the display on the display unit DP. That is, a confirmation operation of pressing the push button switch S2 after confirming the display on the display unit DP is required.
For example, if a note such as "Please check that the operation sound of the machine is not heard before pressing" is written near the push button of the push button switch S2, the push button switch S2
Before the pressing operation of, the operator can detect the operation of the machine by the noise or the like generated inside. Therefore, as in the conventional case, only the display of the indicator light DP is relied upon to inadvertently open the door D.
It is possible to reliably prevent the opening of the.

[0030]

As described above, according to the safety switch device of the present invention, the time from the stop of power supply to the industrial machine installed inside until the machine is completely stopped, or the operation, A timer measures the time it takes for a high temperature part of an industrial machine that is heated to a high temperature to be completely cooled, and the lock mechanism allows the lock to be released when the timer expires. It is possible to reliably prohibit the opening of the door unless it is in a different stopped state, and it is possible to prevent accidents such as being caught in a machine that continues to operate due to inertial force, or being burned by touching a hot spot.

Further, the lock mechanism cannot release the lock unless a display section for displaying the time-out of the timer is provided and the push button switch is inserted and connected to the power supply circuit of the solenoid and the push button switch is pressed. With the configuration, even if the timer is mistakenly started and the time is up due to a programming error or some abnormality in the pluggable controller, the lock by the lock mechanism is not released immediately at that point, and the display on the display is displayed. After confirmation, a confirmation operation of pressing the push button switch is required. Therefore, if precautions for operation are written near the push button switch, it is possible to detect the operation of the machine by the noise generated inside before the push button switch is pressed, and it is possible to detect the operation of the indicator lamp as in the past. You can prevent accidentally opening the door by trusting the display.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an operating state of a machine according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing a state in which a timer has timed out in the embodiment.

FIG. 3 is an electric circuit diagram showing a state where a push button switch in the embodiment is turned on.

FIG. 4 is an electric circuit diagram showing a state in which a door is opened in the above embodiment.

5A to 5F are timing charts of the above-described embodiment.

FIG. 6 is a perspective view showing a mounting state of the above embodiment.

FIG. 7 is a plan view of the switch body unit according to the above embodiment with a cover body removed.

8A to 8C are right side views sequentially showing a part of the operation process of the switch main body unit in the embodiment.

[Explanation of symbols]

1 Switch Main Unit (Main Body) 4 Switching Actuator 21 Lock Lever (Lock Mechanism) 34 Solenoid S1 Safety Switch S2 Push Button Switch TM Timer S3 Timer Switch DP Display P5, P6 Solenoid Power Port (Solenoid Power Supply Circuit) P3 , P4 Main circuit port (power supply main circuit) D Door

Claims (2)

[Claims] 1. A switching actuator attached to a movable member such as a door, and a main body portion fixed to insert and remove the switching actuator when the door is opened and closed. The main body portion includes the switching actuator. Safety switch that can be switched to close and open the main circuit for power supply to the machine by inserting and removing the power switch, and automatically and mechanically to prevent the inserted switching actuator from being pulled out. A lock mechanism for locking the lock mechanism and a solenoid for unlocking the lock mechanism, and a timer for starting a fixed time by inputting an operation-off detection signal that detects interruption of power supply to a machine, and the solenoid. And a timer switch that is turned on when the timer times out Safety switch device characterized by 2. The display device according to claim 1, further comprising a display unit for displaying an ON state of the timer switch, and a push button switch which is inserted and connected to a power supply circuit of the solenoid and which is turned on by a pressing operation. Switch device for safety.