Safety switch

Abstract

To provide a safety switch capable of simplifying the structure, suppressing an increase in power consumption, securely locking an actuator, and improving the reliability.SOLUTION: A safety switch 1 for switching the output state of a switch is constructed by the cooperation of an actuator 2 and a switch body 3. In this case, the actuator 2 has a locking bolt 21 with a tip 22 that can be inserted into the switch body 3. The switch body 3 includes a reciprocating rod 30 and a lock lever 31 that is swingably provided at the tip of the rod 30 and capable of locking the tip 22 of the locking bolt 21 inserted into the switch body 3.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a safety switch that switches the output state of a switch by the cooperation of an actuator and a switch body.

Background Art

[0002] At the entrances and exits of dangerous areas where industrial machines such as machine tools and industrial robots are installed, safety switches that turn on / off according to the opening and closing state of the door are provided.

[0003] Generally, a safety switch includes an actuator disposed on the door side, and a switch body disposed on the wall side and having a cam that rotates by the insertion of the actuator and an operation rod that moves according to the movement of the cam. When the actuator on the door side is inserted into the switch body on the wall side when the door is closed, the door is locked by locking the actuator via the cam and the operation rod, and the contacts are switched by the movement of the operation rod inside the switch body (see FIG. 1 of Japanese Patent Laid-Open No. 2005-294047, etc.).

[0004] In such a safety switch, by using an actuator with a special shape and a cam with a corresponding complex shape, the door is prevented from being locked illegally. On the other hand, if a safety switch that does not use a cam is constructed, the production of a cam with a complex shape becomes unnecessary, and the structure can be simplified.

[0005] Therefore, it is conceivable to directly lock the actuator with the operation rod. In that case, it is assumed that an excessive force directly acts on the operation rod from the actuator as the door opens and closes. Therefore, increasing the shaft diameter of the operation rod to increase the rigidity of the operation rod is one solution, but in that case, the operation rod becomes larger and heavier, and a large amount of power consumption is required to operate the operation rod.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of such a conventional situation, and the problem to be solved by the present invention is to provide a safety switch that can simplify the structure and suppress an increase in power consumption. Further, the present invention aims to reliably lock the actuator and improve the reliability. Safety switch Moreover, in such a safety switch, the present invention aims to surely prevent unauthorized locking.

Means for Solving the Problems

[0007] The safety switch according to the present invention switches the output state of the switch by the cooperation of an actuator and a switch body. The actuator includes a locking bolt having a tip portion that can be inserted into the switch body, and the switch body includes a reciprocating rod and a locking lever that is swingably provided at the tip of the rod and can lock the tip portion of the locking bolt inserted into the switch body. Also, the lock lever is configured to be able to take a lock position where the tip of the locking bolt is locked as it swings along with the movement of the rod, and an unlocking position where the locked state of the tip is released. Further, when the tip of the locking bolt is not inserted into the switch body, the lock lever is configured to swing to an excessive position beyond the lock position.

[0008] In the present invention, when the tip portion of the locking bolt of the actuator is inserted into the bolt insertion hole of the switch body, the swingable locking lever of the switch body locks the tip portion of the locking bolt.

[0009] Thus, according to the present invention, since a cam with a complicated shape is not required to lock the actuator, the structure can be simplified. Also, since the actuator is not directly locked by the rod, the rod does not become large, and an increase in power consumption can be suppressed. Further, according to the present invention, since the locking lever provided at the tip of the rod locks the actuator, the actuator can be surely locked and the reliability as a safety switch can be improved.

[0010] In the present invention, the locking bolt has a shaft portion and a tip portion that is disposed at the tip of the shaft portion and has a larger diameter than the shaft portion, and the locking lever is provided so as to be engageable with a step between the tip portion and the shaft portion.

[0011] In the present invention, the tip surface of the tip portion of the locking bolt has a convex arc-shaped surface or a tapered surface.

[0012] In the present invention, the locking lever includes a shaft support portion pivotally supported by the switch body and a locking convex portion that can engage and disengage the tip portion of the locking bolt in a detachable manner, and is swingably engaged with the tip of the rod at an intermediate position between the shaft support portion and the locking convex portion.

[0015] The present invention further includes proximity detection means for detecting the approach of the actuator and the switch body.

[0016] In the present invention, the proximity detection means has ID information. Thereby, unauthorized locking of the actuator can be reliably prevented.

[0017] The present invention further includes position detection means for detecting the swinging position of the locking lever.

[0018] The present invention further includes proximity detection means for detecting the approach of the actuator and the switch body and position detection means for detecting the swinging position of the locking lever, and outputs a safety signal or an error signal based on the detection results of the proximity detection means and the position detection means.

[0019] In the present invention, when the proximity detection means detects the approach of the actuator and the switch body and the position detection means detects the swinging position at the time of locking of the locking lever, a safety signal is output.

Advantages of the Invention

[0020] As described above, according to the safety switch of the present invention, the structure can be simplified and an increase in power consumption can be suppressed. Further, according to the present invention, the actuator can be reliably locked and the reliability can be improved.

Brief Description of the Drawings

[0021]

Figure 1

Figure 1A

Figure 2

Figure 2A

Figure 3

Figure 3A

Figure 4

Figure 5

Figure 5A

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 11A

Modes for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. <First Embodiment> Figs. 1 to 5A are diagrams for explaining a safety switch according to a first embodiment of the present invention. Figs. 1, 2, and 3 are schematic longitudinal sectional views of the safety switch, showing the operation of each member in chronological order when the actuator is inserted into the switch body. Figs. 1A, 2A, and 3A are schematic cross-sectional views of the safety switch, corresponding to Figs. 1, 2, and 3 respectively. Fig. 4 is a schematic block diagram of the control unit of the safety switch. Fig. 5 is a flowchart by the control unit. Fig. 5A is a diagram showing a list of details of normal operation and abnormal operation in the safety switch. In the following description, the vertical direction in Figs. 1, 2, and 3 will be referred to as the vertical direction.

[0023] As shown in FIGS. 1 and 1A, the safety switch 1 according to this embodiment includes, for example, an actuator 2 disposed on a slide-type movable door (not shown) and a switch body 3 disposed on, for example, a wall or a fixed door (not shown). As the movable door opens and closes, the actuator 2 moves in the left-right direction shown in the figure and is inserted into and removed from the switch body 3, so that the actuator 2 cooperates with the switch body 3 to switch the output state of a switch (not shown) inside the switch body 3. FIG. 1 shows a state in which the movable door is being closed and the movable door is slightly open, and the actuator 2 that moves with the movable door is in a state before being inserted into the switch body 3.

[0024] The actuator 2 has a base 20 attached to the movable door and a locking bolt 21 protruding from the base 20. The locking bolt 21 has, for example, a columnar shaft portion 21A extending in the axial direction and a tip portion 22 disposed at the tip of the shaft portion 21A and insertable into the switch body 3. The tip portion 22 is, for example, a hemispherical protrusion, a member having a larger diameter than the shaft portion 21A, and has a convex arc-shaped surface (or tapered surface) 22a that is a tip surface disposed on the tip side and a flat surface 22b disposed on the rear end side and extending in a direction orthogonal to the axial direction. The tip of the shaft portion 21A is integrally connected to the flat surface 22b. The flat surface 22b forms a step with respect to the tip of the shaft portion 21A. A substantially cylindrical flange portion 23 protruding radially outward is provided at a substantially central portion of the shaft portion 21A. The flange portion 23 has a cylindrical outer peripheral surface 23a. The outer peripheral surface 23a preferably has substantially the same outer diameter as the inner diameter of the actuator insertion hole 3a (or the outer diameter of the tip portion 22) described later. Further, an RF tag 6 is attached (or embedded) to the surface 20A of the base 20 of the actuator 2 that faces the switch body 3.

[0025] As shown in FIGS. 1 and 1A, the switch body 3 has an actuator insertion hole 3a for inserting the tip 22 of the actuator 2. The actuator insertion hole 3a is, for example, a hole having a circular cross-section that opens at one end of the switch body 3, extends in the axial direction of the locking bolt 21 of the actuator 2, and has a tapered surface 3b that tapers inwardly towards the interior of the switch body 3 at its open end. The tapered surface 3b functions as a guide surface when the tip 22 of the actuator 2 is inserted into the actuator insertion hole 3a.

[0026] The switch body 3 has a rod 30 provided so as to be reciprocable in the vertical direction, and a lock lever 31 provided at the tip 30a of the rod 30 so as to be swingable in the vertical direction. The lock lever 31 is a member having a substantially strip shape in plan view (see FIG. 1A), has a shaft support portion 31A (FIG. 1A) pivotally supported by the switch body 3 so as to be rotatable in the vertical direction on the base end side (right side in the drawing), and a locking convex portion 31B as a locking portion capable of locking the tip 22 of the locking bolt 21 on the tip side (left side in the drawing). The locking convex portion 31B is provided so as to be capable of engaging and disengaging with a step in the flat surface 22b of the tip 22 of the locking bolt 21. A rectangular through-hole 31c penetrating the lock lever 31 in the vertical direction is formed at an intermediate position between the shaft support portion 31A and the locking convex portion 31B of the lock lever 31, and a bifurcated engaging portion 31d extending from the shaft support portion 31A side is provided in the through-hole 31c. An engaging recess (a circumferential groove in this example) 30b is formed at a position below the tip 30a of the rod 30, and when the engaging portion 31d of the lock lever 31 engages with the engaging recess 30b of the rod 30, the lock lever 31 swings in the vertical direction around the axis O (FIG. 1) of the shaft support portion 31A as the rod 30 reciprocates in the vertical direction.

[0027] The lock lever 31 can take a lock position (FIG. 3 (described later)) in which it swings upward to lock the tip 22 of the locking bolt 21, and a lock release position (FIG. 1) in which it swings downward to release the locked state of the tip 22 of the locking bolt 21.

[0028] Although not shown, position detection means for detecting the swing position of the lock lever 31 is provided. The position detection means is constituted by, for example, a photoelectric sensor (transmission type or reflection type). In the case of a transmission type photoelectric sensor, it is constituted by oppositely arranging a light projecting section that incorporates a light source and projects light, and a light receiving section that incorporates a light receiving element for receiving the projected light from the light projecting section. The light projecting section and the light receiving section of the photoelectric sensor are arranged at a position where the light from the light projecting section is blocked, for example, by the locking convex portion 31B (or the vicinity of the shaft support portion 31A) of the lock lever 31 that swings upward and moves to the locked position when the lock lever 31 moves to the locked position. That is, the light projecting and receiving sections are arranged on both sides of the locking convex portion 31B (or the vicinity of the shaft support portion 31A) of the lock lever 31 in the locked position with the locking convex portion 31B (or the vicinity of the shaft support portion 31A) of the lock lever 31 in the locked position interposed therebetween. In this case, if the light from the light projecting section is blocked, the lock lever 31 is in the locked position, and if the light from the light projecting section is received by the light receiving section, the lock lever 31 is in a position other than the locked position (for example, the unlocked position). become 。

[0029] Note that since the lock lever 31 is swingably connected to the tip 30a of the rod 30, the swing position of the lock lever 31, that is, the swing angle, is in a correlation with the movement amount of the rod 30. Therefore, the position detection means such as a photoelectric sensor may be arranged at a position where the up-and-down movement of the rod 30 can be detected (for example, the position of a detected portion (not shown) provided on the rod 30). In that case, by detecting the position of the rod 30, the swing position of the lock lever 31 is indirectly detected.

[0030] A solenoid 4 is provided at the lower part of the rod 30. The solenoid 4 has a solenoid body 40 formed by a coil disposed around the rod 30. When current is supplied to the solenoid body 40, the rod 30 is configured to be pulled downward by the electromagnetic force generated in the solenoid body 40. In FIG. 1 (and similarly in FIG. 2 and the second embodiment described later), the solenoid body 40 is shown in thick lines to indicate that current is being supplied to the solenoid body 40. A compression spring 5 is disposed at the lower end of the rod 30, and the compression spring 5 constantly biases the rod 30 upward.

[0031] Also, an RFID (radio frequency identifier) reader 7 is attached (or embedded) to a surface 3A of the switch body 3 that faces the actuator 2. The RFID reader 7 is disposed at a position facing the RF tag 6 of the actuator 2 and is for reading the ID information stored in the RF tag 6. An approach detection means for detecting the approach of the actuator 2 and the switch body 3 is constituted by the RFID composed of these RF tag 6 and RFID reader 7.

[0032] The safety switch 1 includes a control unit 100 as shown in FIG. 4. The control unit 100 has a microcomputer 101. The microcomputer 101 includes a CPU, a memory (such as a ROM and a RAM), etc. An RFID reader 7 and the above-described photoelectric sensor 102 are connected to the input side of the microcomputer 101. An electromagnetic solenoid 4, a safety signal output unit 103, an error signal output unit 104, and an error display unit 105 are connected to the output side of the microcomputer 101.

[0033] Next, an example of the control flow by the control unit 100 will be described with reference to FIGS. 1 to 4 and using FIG. 5. Note that FIG. 5 shows the state until the movable door transitions from the open state to the closed state (open → closed), and the case where the movable door transitions from the closed state to the open state (closed → open) is omitted.

[0034] When the program starts, in step S1 of FIG. 5, the solenoid is turned on. That is, current is supplied to the solenoid body 40 of the electromagnetic solenoid 4. Then, due to the electromagnetic force generated in the solenoid body 40, the rod 30 is pulled in against the elastic repulsive force of the compression spring 5 and moves downward (see FIG. 1). At this time, the lock lever 31 provided at the tip 30a of the rod 30 so as to be swingable in the vertical direction swings downward around the axis O of the shaft support portion 31A, and the locking convex portion 31B at the tip moves to the unlocking position (FIG. 1) where it sinks downward from the inner peripheral surface of the actuator insertion hole 3a. This unlocking position is detected by the photoelectric sensor 102 (FIG. 4).

[0035] Next, in step S2, it waits for the RF tag 6 to be detected. When the movable door is moved in the closing direction (right direction in the figure) from the state shown in FIG. 1, the actuator 2 approaches the switch body 3, and as shown in FIGS. 2 and 2A, the locking bolt 21 of the actuator 2 is inserted into the actuator insertion hole 3a of the switch body 3. At this time, the tip portion 22 of the locking bolt 21 is located above the lock lever 31 inside the switch body 3.

[0036] When the locking bolt 21 is inserted into the actuator insertion hole 3a, not only the tip portion 22 of the locking bolt 21 but also the flange portion 23a is inserted into the actuator insertion hole 3a in the same way, and the outer peripheral surface of the flange portion 23a is in contact with the inner peripheral surface of the actuator insertion hole 3a. Thereby, the locking bolt 21 is centered (positioned) with respect to the actuator insertion hole 3a so that the central axis of the locking bolt 21 coincides with the central axis of the actuator insertion hole 3a. Also, when the locking bolt 21 is inserted into the actuator insertion hole 3a, the RF tag 6 of the actuator 2 approaches the RFID reader 7 of the switch body 3 and the two are arranged in proximity (see FIG. 2). When the RFID reader 7 detects the RF tag 6, it proceeds to step S3.

[0037] In step S3, the ID information stored in the RF tag 6 is read by the RFID reader 7. If the read ID information matches the normal / proper one, the determination in step S3 becomes "Yes" and the process proceeds to step S4.

[0038] In step S4, the solenoid is turned OFF. That is, the supply of current to the solenoid body 40 of the electromagnetic solenoid 4 is stopped. Then, since the electromagnetic force generated in the solenoid body 40 disappears, the rod 30 moves upward due to the elastic repulsive force of the compression spring 5 acting on the lower end of the rod 30. At this time, the lock lever 31 provided swingably in the vertical direction at the tip 30a of the rod 30 swings upward around the axis O of the shaft support portion 31A, and the locking convex portion 31B at the tip projects upward from the inner peripheral surface of the actuator insertion hole 3a. Then, as shown in FIG. 3, the locking surface 31b of the locking convex portion 31B of the lock lever 31 locks the flat surface 22b of the tip portion 22 of the locking bolt 21 from below, thereby locking the locking bolt 21 via the tip portion 22. At this time, the lock lever 31 is arranged at the lock position (FIG. 3). This lock position is detected by the photoelectric sensor 102 (FIG. 4).

[0039] Next, in step S5, it is determined whether or not the lock lever 31 is at the lock position. As described above, if it is detected by the photoelectric sensor 102 that the lock lever 31 has moved to the lock position, the determination in step S5 becomes "Yes" and the process proceeds to step S6.

[0040] In step S6, a safety signal (operation permission signal) is output from the safety signal output unit 103 (FIG. 4). The output safety signal is input to a controller (not shown) of a machine such as a robot installed inside the door, and based on this safety signal, the machine can be driven.

[0041] On the other hand, in step S3, if the read ID information does not match the regular / proper one, the determination in step S3 is "No", and the process proceeds to step S7. In step S7, an error signal is output from the error signal output unit 104 (Fig. 4). Next, in step S8, based on the error signal output in step S7, an error display (for example, a display indicating ID mismatch, etc.) is performed on the error display unit 105 (Fig. 4).

[0042] Also, in step S5, if it is determined that the lock lever 31 is not in the locked position, the determination in step S5 is "No", and the process proceeds to step S9. As a case where the lock lever 31 is not arranged in the locked position, a case where the locking bolt 21 is not inserted into the actuator insertion hole 3a and only the RF tag is brought close to the RFID reader 7 can be considered. In that case, although the lock lever 31 rises, since the locking bolt 21 is not inserted, the lock lever 31 rises beyond the locked position (i.e., over-rises) and moves to the excess position. In this case, the photoelectric sensor 102 does not detect the locked position of the lock lever 31. In step S9, an error signal is output from the error signal output unit 104 (Fig. 4). Next, in step S10, based on the error signal output in step S9, an error display (for example, a display indicating no locking bolt, etc.) is performed on the error display unit 105 (Fig. 4).

[0043] Next, in step S11, the solenoid is turned ON. That is, by supplying current to the solenoid body 40 of the electromagnetic solenoid 4 to move the rod 30 downward, the lock lever 31 is swung downward and moved to the unlock position (Fig. 1). After the process in step S11, the program returns to step S2, and the processes of steps S2 to S5 are repeated. When only the RF tag is brought close to the RFID reader 7 without inserting the locking bolt 21 into the actuator insertion hole 3a, the processes of step S2 → S3 → S4 → S5 → S9 → S10 → S11 are repeated. At this time, if the RF tag is moved away from the RFID reader 7, the system enters a standby state at the position of step S2.

[0044] Thus, according to this embodiment, since a cam with a complex shape is not required to lock the actuator 2, the structure can be simplified. Also, since the actuator 2 is not directly locked by the rod 30, the rod 30 does not become large-sized, and an increase in power consumption can be suppressed. Furthermore, according to this embodiment, since the lock lever 31 provided at the tip 30a of the rod 30 locks the actuator 2, the actuator 2 can be reliably locked, and the reliability as the safety switch 1 can be improved. Moreover, according to this embodiment, since the RF tag 6 stores the ID information, unauthorized locking of the actuator 2 can be surely prevented.

[0045] In this embodiment, as shown in the flow of steps S2 to S11 described above, a safety signal or an error signal is output based on the detection results of the proximity detection means using RFID composed of the RF tag 6 and the RFID reader 7, and the position detection means composed of the photoelectric sensor 102. Also, as shown in the flow of steps S2 to S6, the proximity detection means detects the approach of the actuator 2 and the switch body 3, and when the position detection means detects the swing position at the time of locking of the lock lever 31, that is, the lock position, a safety signal is output. Therefore, the reliability as the safety switch 1 can be further improved.

[0046] Here, FIG. 5A shows the details of the normal operation and abnormal operation of the safety switch 1 described above. The normal operation of the safety switch 1 is shown as No. 1-A and 1-B in the figure. In the door open (OPEN) state shown as No. 1-A, the locking bolt 21 is not inserted into the switch body 3, there is no detection by RFID, the solenoid body 40 is energized, the lock lever 31 is in the unlocked position, and the machine inside the door has stopped operating (refer to step S1 in FIGS. 1 and 5). At this time, the door is in the unlocked state, and neither an error signal nor a safety signal is output. In the door closed (CLOSED) state shown as No. 1-B, the locking bolt 21 is inserted into the switch body 3, detection by RFID is performed, the solenoid body 40 is de-energized, the lock lever 31 is in the locked position, the door is locked, no error signal is output, and a safety signal is output (refer to steps S2→S3→S4→S5→S6 in FIGS. 3 and 5). As a result, the machine inside the door is operating.

[0047] The abnormal operation of the safety switch 1 is shown as No. 2-A to 3-B in the figure. In the door open (OPEN) state shown as No. 2-A, the locking bolt 21 is not inserted into the switch body 3, detection by RFID is performed by approaching only the RF tag (refer to paragraph

[0042] ), the solenoid body 40 is de-energized, the lock lever 31 is in the over-risen over-position, the door is not locked, no safety signal is output, and an error signal is output (refer to steps S5→S9 in FIG. 5). As a result, the machine inside the door has stopped operating. In the door closed (CLOSED) state shown as No. 2-B, the locking bolt 21 is inserted into the switch body 3, there is no detection by RFID because the RF tag does not approach, the solenoid body 40 is energized, the lock lever 31 is in the unlocked position, the door is not locked, and neither an error signal nor a safety signal is output. At this time, the program is in a standby state at step S2 in FIG. 5, and the machine inside the door has stopped operating.

[0048] In the door closed state shown in No.2-C, although the locking bolt 21 is inserted into the switch body 3 and detection by RFID is performed because an RF tag approaches, since the RF tag is different, the solenoid body 40 remains energized due to an ID mismatch. The lock lever 31 is in the unlocking position, the door is not locked, and neither an error signal nor a safety signal is output. At this time, the program is in a standby state at step S2 of FIG. 5, and the machinery inside the door has stopped operating.

[0049] In the door open state shown in No.3-A, since the power supply of the control circuit is OFF, the solenoid body 40 is de-energized, and since the locking bolt 21 is not inserted into the switch body 3, the lock lever 31 is in an over-elevated over-position and there is no detection by RFID. At this time, the door is in an unlocked state and neither an error signal nor a safety signal can be output. Regarding the door blockage (CLOSED) state, it corresponds to the state where the door is closed from the door open (OPEN) state shown in No.3-A. When the locking bolt 21 is inserted into the switch body 3, the tip 22 of the locking bolt 21 gradually pushes down the lock lever 31 in the over-position, causing the lock lever 31 to shift to the locking position, locking the locking bolt 21 and locking the door. At this time, since a safety signal cannot be output, the machinery inside the door has stopped operating.

[0050] After the operation of the machinery inside the door has stopped, upon receiving an unlocking signal from the machinery side, current is supplied to the electromagnetic solenoid 4 to move the rod 30 downward, thereby releasing the locked state of the locking bolt 21 by the lock lever 31. As a result, the door becomes unlocked and can be opened.

[0051] <Second Embodiment> Figs. 6 and 7 are schematic longitudinal sectional configuration diagrams for explaining a safety switch according to a second embodiment of the present invention, showing the operations of respective members in chronological order when an actuator is inserted into a switch body. The vertical direction and the horizontal direction in each figure are referred to as the vertical direction and the horizontal direction, respectively. In these figures, the same reference numerals as those in the first embodiment denote the same or corresponding parts. Fig. 6 corresponds to Fig. 1 of the first embodiment, and Fig. 7 corresponds to Fig. 3 of the first embodiment.

[0052] In the first embodiment, position detecting means for detecting the rocking position of the lock lever 31 is not shown, but in this second embodiment, the position detecting means is shown. As shown in Fig. 6, the lower end of the rod 30 branches into two forks and extends downward respectively, having a first lower end portion 30C and a second lower end portion 30D. The second lower end portion 30D extends further downward than the first lower end portion 30C, and a through hole 30d in the horizontal direction is formed at its lower end. On both the left and right sides sandwiching the first lower end portion 30C, as position detecting means, for example, a photoelectric sensor (transmission type (or reflection type)) is provided. The photoelectric sensor is configured by oppositely arranging a light projecting portion 102a having a built-in light source for projecting light and a light receiving portion 102b having a built-in light receiving element for receiving the projected light from the light projecting portion 102a. Similarly, on both the left and right sides sandwiching the second lower end portion 30D, as position detecting means, for example, a photoelectric sensor (transmission type (or reflection type)) is provided. The photoelectric sensor is configured by oppositely arranging a light projecting portion 102c having a built-in light source for projecting light and a light receiving portion 102d having a built-in light receiving element for receiving the projected light from the light projecting portion 102c.

[0053] Therefore, in the second embodiment, the position detecting means directly detects the vertical position of the rod 30, thereby indirectly detecting the rocking position, that is, the rocking angle of the lock lever 31 interlocked with the vertical movement of the rod 30.

[0054] Regarding the safety switch 1 according to this second embodiment as well, it is provided with the same control unit 100 (FIG. 4) as in the first embodiment, and the control unit 100 processes according to the same flowchart as in the above embodiment.

[0055] That is, when the program starts, in step S1 of FIG. 5, the solenoid is turned on. That is, current is supplied to the solenoid body 40 of the electromagnetic solenoid 4 (see FIG. 6). Then, due to the electromagnetic force generated in the solenoid body 40, the rod 30 is pulled in while resisting the elastic repulsive force of the compression spring 5 and moves downward (see FIG. 6). At this time, the lock lever 31 provided swingably in the vertical direction at the tip 30a of the rod 30 swings downward around the axis O of the shaft support portion 31A, and the locking convex portion 31B at the tip moves to the unlocking position (FIG. 6) where it sinks downward from the inner peripheral surface of the actuator insertion hole 3a.

[0056] When the lock lever 31 is in the unlocking position, as shown in FIG. 6, the first lower end portion 30C of the rod 30 blocks the light projected from the light projecting portion 102a to the light receiving portion 102b of the photoelectric sensor, and the photoelectric sensor is OFF. Similarly, the second lower end portion 30D of the rod 30 blocks the light projected from the light projecting portion 102c to the light receiving portion 102d of the photoelectric sensor, and the photoelectric sensor is also OFF. Thereby, based on the OFF signals from the respective photoelectric sensors, the unlocking position of the lock lever 31 is detected.

[0057] Next, in step S2, it waits for the RF tag 6 to be detected. When the movable door is moved in the closing direction (right direction in the figure) from the state shown in FIG. 6, the actuator 2 approaches the switch body 3, and the locking bolt 21 of the actuator 2 is inserted into the actuator insertion hole 3a of the switch body 3. At this time, although not shown, the tip portion 22 of the locking bolt 21 is located above the lock lever 31 inside the switch body 3, and the RF tag 6 of the actuator 2 approaches and is disposed in proximity to the RFID reader 7 of the switch body 3. When the RFID reader 7 detects the RF tag 6, it proceeds to step S3.

[0058] In step S3, the ID information stored in the RF tag 6 is read by the RFID reader 7. If the read ID information matches the regular / proper one, the determination in step S3 becomes "Yes", and the process proceeds to step S4.

[0059] In step S4, the solenoid is turned OFF. That is, the supply of current to the solenoid body 40 of the electromagnetic solenoid 4 is stopped. Then, since the electromagnetic force generated in the solenoid body 40 disappears, the rod 30 moves upward due to the elastic repulsive force of the compression spring 5 acting on the lower end of the rod 30. At this time, the lock lever 31 provided so as to be vertically swingable at the tip 30a of the rod 30 swings upward around the axis O of the shaft support portion 31A, and the locking convex portion 31B at the tip projects upward from the inner peripheral surface of the actuator insertion hole 3a. Then, as shown in FIG. 7, the locking surface 31b of the locking convex portion 31B of the lock lever 31 locks the flat surface 22b of the tip portion 22 of the locking bolt 21 from below, thereby locking the locking bolt 21 via the tip portion 22. At this time, the lock lever 31 is disposed at the lock position (FIG. 7).

[0060] When the lock lever 31 is in the lock position, as shown in FIG. 7, the first lower end portion 30C of the rod 30 does not block the light projected from the light projecting portion 102a to the light receiving portion 102b of the photoelectric sensor, and the photoelectric sensor is ON. On the other hand, the second lower end portion 30D of the rod 30 is disposed at a position where the through hole 30d faces the light projecting portion 102c and the light receiving portion 102d of the photoelectric sensor, and the light projected from the light projecting portion 102c passes through the through hole 30d and is received by the light receiving portion 102d, whereby the photoelectric sensor is also ON. Thus, based on the ON signals from the respective photoelectric sensors, the lock position of the lock lever 31 is detected.

[0061] Next, in step S5, it is determined whether or not the lock lever 31 is in the lock position. As described above, if it is detected by the photoelectric sensor 102 that the lock lever 31 has shifted to the lock position, the determination in step S5 becomes "Yes", and the process proceeds to step S6.

[0062] In step S6, a safety signal (operation permission signal) is output from the safety signal output unit 103 (Fig. 4). The output safety signal is input to a controller (not shown) of a machine such as a robot installed inside the door, and based on the safety signal, the machine can be driven.

[0063] On the other hand, in step S3, if the read ID information does not match the normal / appropriate one, the determination in step S3 becomes "No", and the process proceeds to step S7. In step S7, an error signal is output from the error signal output unit 104 (Fig. 4). Next, in step S8, based on the error signal output in step S7, an error display (for example, a display such as ID mismatch) is performed on the error display unit 105 (Fig. 4).

[0064] Also, in step S5, if it is determined that the lock lever 31 is not in the locked position, the determination in step S5 becomes "No", and the process proceeds to step S9. As a case where the lock lever 31 is not arranged in the locked position, for example, when the locking bolt 21 is not inserted into the actuator insertion hole 3a and only the RF tag is brought close to the RFID reader 7 (No. 2-A in Fig. 5A). In that case, the lock lever 31 rises, but since the locking bolt 21 is not inserted, the lock lever 31 rises beyond the locked position (i.e., over-rises) and moves to the excess position. In this case, the photoelectric sensor 102 does not detect the locked position of the lock lever 31. Also, the excess position of this lock lever 31 can be detected by the photoelectric sensor 102 (see Fig. 8 and paragraph

[0071] described later). In step S9, an error signal is output from the error signal output unit 104 (Fig. 4). In step S10, based on the error signal output in step S9, an error display (for example, a display such as no locking bolt) is performed on the error display unit 105 (Fig. 4).

[0065] Next, in step S11, the solenoid is turned ON. That is, a current is supplied to the solenoid body 40 of the electromagnetic solenoid 4 to move the rod 30 downward, thereby swinging the lock lever 31 downward and moving it to the unlock position (FIG. 6). After the process in step S11, the program returns to step S2, and the processes of steps S2 to S5 are repeated. When only the RF tag is brought close to the RFID reader 7 without inserting the lock bolt 21 into the actuator insertion hole 3a, the processes of step S2 → S3 → S4 → S5 → S9 → S10 → S11 are repeated. At this time, if the RF tag is moved away from the RFID reader 7, it enters the standby state at the position of step S2.

[0066] As described above, according to this embodiment, since a cam with a complicated shape is not required to lock the actuator 2, the structure can be simplified. Further, since the actuator 2 is not directly locked by the rod 30, the rod 30 does not become large-sized, and an increase in power consumption can be suppressed. Furthermore, according to this embodiment, since the lock lever 31 provided at the tip 30a of the rod 30 locks the actuator 2, the actuator 2 can be reliably locked, and the reliability as the safety switch 1 can be improved. Moreover, according to this embodiment, since the RF tag 6 stores the ID information, unauthorized locking of the actuator 2 can be reliably prevented.

[0067] In this embodiment, as shown in the flow of steps S2 to S11 described above, a safety signal or an error signal is output based on the detection results of the proximity detection means using RFID composed of the RF tag 6 and the RFID reader 7 and the position detection means composed of the photoelectric sensor 102. Further, as shown in the flow of steps S2 to S6, the proximity detection means detects the approach of the actuator 2 and the switch body 3, and when the position detection means detects the swing position at the time of locking of the lock lever 31, that is, the lock position, a safety signal is output. Therefore, the reliability as the safety switch 1 can be further improved.

[0068] <The Third Embodiment> Figures 8 to 11A are diagrams for explaining the safety switch according to the third embodiment of the present invention. Figures 8 to 10 are schematic longitudinal sectional configuration diagrams of the safety switch, showing the operations of the respective members when the actuator is inserted into the switch body in chronological order. Figure 11 is a flowchart by the control unit, and Figure 11A is a diagram showing a list of details of normal operation and abnormal operation in the safety switch. In Figures 8 to 10, the vertical direction and the horizontal direction will be referred to as the vertical direction and the horizontal direction, respectively. In these figures, the same reference numerals as those in the first and second embodiments indicate the same or corresponding parts.

[0069] The configuration (mechanical structure) of the safety switch 1 in the third embodiment is the same as that of the safety switch 1 shown in the second embodiment. However, in this third embodiment, the control method is different from that of the second embodiment. Note that Figure 11 shows the situation until the movable door shifts from the open state to the closed state (open → closed), and the case where the movable door shifts from the closed state to the open state (closed → open) is omitted.

[0070] When the program starts, at step T1 in Figure 11, it is determined whether the lock lever 31 is in an excessive position beyond the lock position. At the start of the program, the solenoid is in the OFF state. Therefore, no current is supplied to the solenoid body 40 of the electromagnetic solenoid 4, or the supply current to the solenoid body 40 has been stopped (see Figure 8). At this time, since no electromagnetic force is generated in the solenoid body 40, the rod 30 moves upward due to the elastic repulsive force of the compression spring 5, and the lock lever 31 swings upward around the axis O of the shaft support portion 31A. At this point, since the locking bolt 21 is not inserted into the actuator insertion hole 3a, the lock lever 31 moves further upward beyond the lock position (i.e., over-rises) and moves to the excessive position (see Figure 8). At this time, the locking convex portion 31B at the tip of the lock lever 31 protrudes upward from the inner peripheral surface of the actuator insertion hole 3a (see Figure 8).

[0071] When the lock lever 31 is in the excessive position, as shown in FIG. 8, the first lower end portion 30C of the rod 30 does not block the light projected from the light projecting portion 102a to the light receiving portion 102b of the photoelectric sensor, and the photoelectric sensor is ON. On the other hand, the second lower end portion 30D of the rod 30 is arranged at a position where the lowermost end portion faces the light projecting portion 102c and the light receiving portion 102d of the photoelectric sensor, and the light projected from the light projecting portion 102c is blocked by the lowermost end portion, and the photoelectric sensor is OFF. Thus, based on the ON signal and OFF signal from each photoelectric sensor, the excessive position of the lock lever 31 is detected. Thereby, the determination in step T1 becomes "Yes", and the process proceeds to step T2.

[0072] When the locking bolt 21 of the actuator 2 is inserted into the actuator insertion hole 3a from the state shown in FIG. 8 where the lock lever 31 is in the excessive position, as shown in FIG. 9, the convex arc-shaped surface 22a of the tip portion 22 of the locking bolt 21 abuts against the locking convex portion 31B of the lock lever 31. When the locking bolt 21 is further inserted into the actuator insertion hole 3a from this state, the convex arc-shaped surface 22a of the tip portion 22 of the locking bolt 21 swings the lock lever 31 downward and moves the rod 30 downward via the lock lever 31. At this time, the rod 30 moves downward against the elastic repulsive force of the compression spring 5, and during the downward movement of the rod 30, the rod 30 is constantly biased upward by the action of the elastic repulsive force of the compression spring 5. Then, at the moment when the flat surface 22b of the tip portion 22 of the locking bolt 21 exceeds the locking surface 31b of the locking convex portion 31B of the lock lever 31, the lock lever 31 swings upward, and the locking surface 31b of the locking convex portion 31B of the lock lever 31 locks the flat surface 22b of the tip portion 22 of the locking bolt 21 from below (see FIG. 9). Thereby, the locking bolt 21 is locked, and at this time, the lock lever 31 is arranged at the locking position (FIG. 10).

[0073] When the lock lever 31 is in the locked position, as shown in FIG. 10, the first lower end portion 30C of the rod 30 does not block the light projected from the light projecting portion 102a to the light receiving portion 102b of the photoelectric sensor, and the photoelectric sensor is ON. On the other hand, the second lower end portion 30D of the rod 30 is disposed at a position where the through hole 30d faces the light projecting portion 102c and the light receiving portion 102d of the photoelectric sensor, and the light projected from the light projecting portion 102c passes through the through hole 30d and is received by the light receiving portion 102d. Thus, the photoelectric sensor is also ON. Based on the ON signals from the respective photoelectric sensors, the locked position of the lock lever 31 is detected.

[0074] On the other hand, in step T2, it is waiting for the lock lever 31 to move to the locked position. If the lock lever 31 moves to the locked position, the determination in step T2 becomes "Yes" and the process proceeds to step T3. In step T3, the RFID is enabled, that is, the RF tag 6 is set to a detectable state. Next, in step T4, it is determined whether the RF tag 6 has been detected.

[0075] When the locking bolt 21 finishes inserting into the actuator insertion hole 3a, the RF tag 6 on the actuator 2 side is detected by the RFID reader 7 on the switch body 3 side. Thus, the determination in step T4 becomes "Yes" and the process proceeds to step T5.

[0076] In step T5, the ID information stored in the RF tag 6 is read by the RFID reader 7, and it is determined whether the read ID information matches the normal / appropriate one. If the ID information matches, the process proceeds to step T6.

[0077] In step T6, a safety signal (operation permission signal) is output from the safety signal output unit 103 (FIG. 4). The output safety signal is input to a controller (not shown) of a machine such as a robot installed inside the door, and based on the safety signal, the machine can be driven.

[0078] On the other hand, in step T4, if it is determined that the RF tag 6 is not detected, the determination in step T4 becomes "No" and the process proceeds to step T7. Also, even if the RFID is detected in step T4 and the process proceeds to step T5, but the ID is determined to be inconsistent in step T5, the process also proceeds to step T7. In step T7, an error signal is output from the error signal output unit 104 (Fig. 4). In step T8, based on the error signal output in step T7, an error display (for example, a display such as "no (regular) RF tag") is performed on the error display unit 105 (Fig. 4).

[0079] Next, in step T9, the solenoid is turned on. That is, a current is supplied to the solenoid body 40 of the electromagnetic solenoid 4 to move the rod 30 downward, thereby swinging the lock lever 31 downward and moving it to the unlock position. The movement to the unlock position is detected by each photoelectric sensor (see paragraphs

[0055] ~

[0056] ).

[0080] Thus, according to this embodiment, since a cam with a complicated shape is not required to lock the actuator 2, the structure can be simplified. Also, since the rod 30 does not directly lock the actuator 2, the rod 30 does not become large, and an increase in power consumption can be suppressed. Furthermore, according to this embodiment, since the lock lever 31 provided at the tip 30a of the rod 30 locks the actuator 2, the actuator 2 can be reliably locked and the reliability as the safety switch 1 can be improved. Moreover, according to this embodiment, since the RF tag 6 stores the ID information, unauthorized locking of the actuator 2 can be reliably prevented.

[0081] In this embodiment, as shown in the flow of steps T1 to T9 described above, a safety signal or an error signal is output based on the detection results of the position detection means composed of the photoelectric sensor 102 and the proximity detection means by RFID composed of the RF tag 6 and the RFID reader 7. Further, as shown in the flow of steps T1 to T6, when the position detection means detects the rocking position at the time of locking of the lock lever 31, that is, the lock position, and the proximity detection means detects the proximity of the actuator 2 and the switch body 3, a safety signal is output. Therefore, the reliability as the safety switch 1 can be further improved.

[0082] In the first embodiment, it is necessary to continuously supply current to the electromagnetic solenoid 4 while the door is open. However, in this third embodiment, it is not necessary, and current only needs to be supplied to the electromagnetic solenoid 4 only when releasing the locked state after an error occurs. Therefore, power consumption can be reduced.

[0083] Here, FIG. 11A shows the details of the normal operation and abnormal operation of the safety switch 1 described above. The normal operation of the safety switch 1 is shown in Nos. 1 to 3 in the figure. No. 1 is in the door open (OPEN) state, before the locking bolt 21 is inserted into the switch body 3. The solenoid body 40 is de-energized, the lock lever 31 is arranged at an over-position beyond the lock position, the RFID is invalid and there is no detection by RFID, the door is in the unlocked state, and neither an error signal nor a safety signal is output (see step T1 in FIGS. 8 and 11). At this time, the machine inside the door has stopped operating. No. 2 is during the transition from the door open (OPEN) state of No. 1 to the door closed (CLOSED) state. The locking bolt 21 is being inserted into the switch body 3. The solenoid body 40 is de-energized, the lock lever 31 is being pushed down by the locking bolt 21 and moving towards the lock position. The RFID is invalid and there is no detection by RFID. The machine inside the door has stopped operating (see step T2 in FIGS. 9 and 11). No. 3 is in the door closed (CLOSED) state after transitioning from No. 2. The locking bolt 21 has completed insertion into the switch body 3. The solenoid body 40 is de-energized, the lock lever 31 is arranged at the lock position. Triggered by this, the RFID is valid and detection is performed by RFID. At this time, the door is in the locked state, no error signal is output, and a safety signal is output (see steps T3 to T6 in FIGS. 10 and 11). The machine inside the door is operating.

[0084] The abnormal operations of the safety switch 1 are shown as No. 4a, 4b, and 5 in the figure. In the operation mode shown as No. 4a, from the state where the solenoid body 40 is non-excited and the lock lever 31 is arranged at the excessive position in the door closed (CLOSED) state, the locking bolt 21 is inserted into the switch body 3, and the locking bolt 21 is once locked by the lock lever 31 (see steps T1 - T2 in FIGS. 8 - 10 and FIG. 11). However, since the RF tag is not detected by the valid RFID, the solenoid body 40 is excited to lower the lock lever 31 (steps T3→T4→T7→T8→T9 in FIG. 11). At this time, an error signal of RFID non-detection is output and the safety signal is not output, the door is in the unlocked state, and the machine inside the door stops operating. The operation mode of No. 4a is an example of RFID non-detection. However, the operation mode shown as No. 4b is an example where the RFID has a different ID, and other conditions are the same as those of No. 4a. In this case, similar to the case of No. 4a, after the locking bolt 21 inserted into the switch body 3 is once locked by the lock lever 31 (see steps T1 - T2 in FIGS. 8 - 10 and FIG. 11), since the normal RF tag is not detected by the valid RFID, the solenoid body 40 is excited to lower the lock lever 31, unlock the door, and output an error signal indicating different IDs (see steps T4→T5→T7→T8→T9 in FIG. 11). The operation mode shown as No. 5 is an example where, from the state where the solenoid body 40 is non-excited and the lock lever 31 is arranged at the excessive position in the door closed (CLOSED) state (see step T1 in FIGS. 8 and 11), only the RF tag is brought close to the RFID reader without inserting the locking bolt 21 into the switch body 3. In this case, since the lock lever 31 does not move to the locking position, the program stops at step T2. At this time, the door is in the unlocked state, and neither the error signal nor the safety signal is output.

[0085] After the operation of the machine inside the door stops, the unlocking button (not shown) becomes operable. When the operator operates the unlocking button, current is supplied to the electromagnetic solenoid 4 and the rod 30 moves downward. As a result, the locking state of the locking bolt 21 by the locking lever 31 is released. In this way, the door becomes unlocked and can be opened.

[0086] <Example 4> In the first to third embodiments described above, an example using RFID is shown as the proximity detection means for detecting the approach of the actuator 2 and the switch body 3. However, the application of the present invention is not limited to this. Other sensors (for example, non-contact ID sensors, etc.) may be adopted.

[0087] 〔Other Modification Examples〕 The above-described embodiments and each modification example should be regarded only as illustrative examples of the present invention in every respect and are not limiting. Those skilled in the art related to the present invention can construct various modification examples and other embodiments that adopt the principles of the present invention without departing from the spirit and essential features of the present invention when considering the above teachings even without explicit description in this specification.

Industrial Applicability

[0088] The present invention is useful for a safety switch that switches the output state of the switch by the cooperation of the actuator and the switch body.

Explanation of Reference Numerals

[0089] 1: Safety switch 2: Actuator 21: Locking bolt 21A: Shaft portion 22: Tip portion 22a: Convex arc-shaped surface (tip surface) 22b: Flat surface 3: Switch body 30: Rod 30a: Tip 31: Lock lever 31A: Shaft support part 31B: Locking convex part 6, 7: Proximity detection means 6: RF tag 7: RFID reader 102, 102a - 102d: Photoelectric sensor (position detection means) 103: Safety signal output part 104: Error signal output part

Prior art documents

Patent documents

[0090]

Patent Document 1

Claims

1. A safety switch that switches the output state of the switch by the cooperation of an actuator and a switch body, wherein the actuator includes a locking bolt having a tip that can be inserted into the switch body, the switch body includes a reciprocating rod and a locking lever that is swingably provided at the tip of the rod and can lock the tip of the locking bolt inserted into the switch body, the locking lever can take a locking position in which the locking lever swings with the movement of the rod to lock the tip of the locking bolt and a unlocking position in which the locked state of the tip is released, when the tip of the locking bolt is not inserted into the switch body, the locking lever swings to an excessive position beyond the locking position, characterized in that it is a safety switch.

2. In Claim 1, the locking bolt has a shaft portion and a tip portion disposed at the tip of the shaft portion and having a larger diameter than the shaft portion, and the locking lever is provided so as to be lockable to a step between the tip portion and the shaft portion, characterized in that it is a safety switch.

3. In Claim 1 or 2, the tip surface of the tip portion of the locking bolt has a convex arc-shaped surface or a tapered surface, characterized in that it is a safety switch.

4. In any one of Claims 1 to 3, the locking lever includes a shaft support portion pivotally supported by the switch body and a locking convex portion that can detachably lock the tip portion of the locking bolt, and is swingably engaged with the tip of the rod at an intermediate position between the shaft support portion and the locking convex portion, characterized in that it is a safety switch.

5. In Claim 1, further comprising proximity detection means for detecting the approach of the actuator and the switch body, characterized in that it is a safety switch.

6. In Claim 5, the proximity detection means has ID information, characterized in that it is a safety switch.

7. In Claim 1, further comprising position detection means for detecting the swing position of the locking lever, characterized in that it is a safety switch.

8. In Claim 1, further comprising proximity detection means for detecting the approach of the actuator and the switch body, and position detection means for detecting the swing position of the locking lever, Based on the detection results of the proximity detection means and the position detection means, it outputs a safety signal or outputs an error signal. A safety switch characterized by this.

9. In claim 8, When the proximity detection means detects the proximity of the actuator and the switch body, and the position detection means detects the swinging position when the lock lever is locked, a safety signal is output. A safety switch characterized by this.

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