Operation switch with operation support function, emergency stop switch with operation support function and operation switch

Abstract

To enable safer operation support without a mechanical latch mechanism.SOLUTION: An emergency stop switch 1 with an operation support function includes a push button 2 that can be manually pushed in, an operation axis 3 connected to the push button, a compression spring 4 that exerts first force F1 along the pushing direction of the push button 2 on the operation shaft 3, and a solenoid body 51 that acts second force F2 in the direction opposite to the action direction of the first force F1 on the operation shaft 3. Before the manual pushing operation of the push button 2, the second force F2 is larger than the first force F1 and a contact 11 is in the ON state. After the manual push operation of the push button 2 or after the operation support of the push button 2, the first force F1 is larger than the second force F2, and the contact 11 is in the OFF state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an operation switch with an operation support function, an emergency stop switch with an operation support function, and an operation switch, which have an operation portion that can be manually pressed. [Background technology]

[0002] An emergency stop switch generally has a push button that can be pressed by an operator, an operating shaft that moves when the push button is pressed, and contacts that are made and broken in response to the movement of the operating shaft (see Figure 1 of JP 2001-35302 A). When the push button is pressed, the operating shaft moves and the contacts switch from an ON state to an OFF state, thereby interrupting the electrical circuit and bringing the machine or system to an emergency stop. Summary of the Invention [Problem to be solved by the invention]

[0003] Before the push button of an emergency stop switch is pressed (i.e., when the contacts are in the ON state), the push button is held in place by a mechanical latch mechanism, and in order for an operator to press the push button, they must apply a pressing force sufficient to overcome the holding force of this mechanical latch mechanism.

[0004] Furthermore, with emergency stop switches, the operator must be very close to the switch when pressing the push button, and cannot operate it from a distance. Therefore, there was a demand for an emergency stop switch with an operation assistance function that would enable safer operation assistance even from a distance.

[0005] The present invention has been made in consideration of the above-described conventional situation, and the problem that the present invention aims to solve is to provide an operation switch with an operation assistance function, an emergency stop switch with an operation assistance function, and an operation switch that do not have a mechanical latch mechanism and can provide operation assistance more safely. [Means for solving the problem]

[0006] The emergency stop switch with operation assistance function according to the present invention comprises a push button that can be pressed manually or with operation assistance, an operating shaft connected to the push button for switching contacts, first acting means for applying a first force to the operating shaft in the direction in which the push button is pressed, and second acting means for applying a second force to the operating shaft in a direction opposite to the direction in which the first force applied by the first acting means. Before the push button is pressed manually or with operation assistance, the second force applied by the second acting means is greater than the first force applied by the first acting means, and the contacts are in a first state. After the push button is pressed manually or with operation assistance, the first force applied by the first acting means is greater than the second force applied by the second acting means, and the contacts are in a second state different from the first state. The second acting means is an actuator, and the actuator applies a second force to the operating shaft when energized, at least in the first state.

[0007] According to the present invention, before the push button is pressed manually or by operational assistance, the second force by the second acting means is greater than the first force by the first acting means, and the contacts are in a first state, and after the push button is pressed manually or by operational assistance, the first force by the first acting means is greater than the second force by the second acting means, and the contacts are in a second state different from the first state. The second acting means is an actuator, and the actuator applies a second force to the operating shaft when energized, at least in the first state. Therefore, to manually press the push button, an external pressing force must be applied in the pushing direction of the push button, which is the direction of action of the first force, thereby preventing accidental manual pressing without using a mechanical latch mechanism. Moreover, to manually return the push button, an external pulling force must be applied to the push button in the same direction as the acting direction of the second force, thereby preventing easy manual return without using a mechanical latch mechanism. In this way, an emergency stop switch with an operation assistance function that does not have a mechanical latch mechanism can be realized.

[0008] Furthermore, according to the present invention, before the push button is manually pressed, if the second force applied by the second acting means is made smaller than the first force applied by the first acting means, the contacts will transition from the first state to the second state, making it easy to provide operational assistance. Furthermore, according to the present invention, the second acting means is an actuator, and the actuator applies a second force to the operating shaft when energized at least in the first state, thereby realizing an operating switch with an operation assistance function that takes fail-safe into consideration and is capable of providing safer operation assistance.

[0009] In the present invention, the first acting means is an elastic member.

[0011] In the present invention, the first acting means is a compression spring, and the second acting means is an electromagnetic solenoid.

[0014] The present invention further comprises a detection unit that detects a change in the state of the contact.

[0015] The present invention further comprises a holding means for applying a holding force to the operating shaft from the outer periphery side. [Effects of the Invention]

[0025] As described above, according to the present invention, a locking mechanism without a mechanical latch mechanism is provided. Bad Not only can a permanent stop switch be realized, but it also makes it easier to provide safer operational assistance with fail-safe measures taken into consideration. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic vertical cross-sectional view of an emergency stop switch according to a first embodiment of the present invention, showing a state before a push button is pressed. [Figure 2] This shows the state of the emergency stop switch (Fig. 1) when the push button is manually pressed. [Figure 3] This shows the state of the emergency stop switch (FIG. 1) after the push button has been manually pressed. [Figure 4] This shows the state of the emergency stop switch (Fig. 1) during manual reset operation of the push button. [Figure 5]This shows the state of the emergency stop switch (Fig. 1) after the push button has been manually reset. [Figure 6] This shows the state of the emergency stop switch (Fig. 1) when assisting with the operation of the push button. [Figure 7] This shows the state of the emergency stop switch (FIG. 1) after the return operation from the push button operation support. [Figure 8A] This is a graph showing the relationship between the first force F1 applied by the first acting means and the second force F2 applied by the second acting means and the depression stroke of the push button in the emergency stop switch (Figure 1), and shows the changes when the push button is manually depressed. [Figure 8B] This is a graph showing the relationship between the first force F1 applied by the first acting means and the second force F2 applied by the second acting means and the depression stroke of the push button in the emergency stop switch (Figure 1), and shows the change during the manual return operation of the push button. [Figure 9] FIG. 10 is a schematic vertical cross-sectional view of a push button portion of an emergency stop switch according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a schematic vertical cross-sectional view of an emergency stop switch according to a third embodiment of the present invention, showing a state before the push button is pressed. [Figure 11] This shows the state of the emergency stop switch (FIG. 10) when the push button is manually pressed. [Figure 12] This shows the state of the emergency stop switch (FIG. 10) after the push button has been manually pressed. [Figure 13] This shows the state of the emergency stop switch (FIG. 10) when the push button is manually reset. [Figure 14] This shows the state of the emergency stop switch (FIG. 10) after the push button has been manually reset. [Figure 15] This shows the state of the emergency stop switch (FIG. 10) when assisting with the operation of the push button. [Figure 16]This shows the state of the emergency stop switch (FIG. 10) after the return operation from the push button operation support. [Figure 17] FIG. 10 is a schematic vertical cross-sectional view of an emergency stop switch according to a fourth embodiment of the present invention, showing a state before the push button is pressed. [Figure 18] This shows the state of the emergency stop switch (FIG. 17) when the push button is manually pressed. [Figure 19] In the emergency stop switch (FIG. 17), the electromagnetic solenoid is turned off after the push button is manually pressed. [Figure 20] This shows the state of the emergency stop switch (FIG. 19) when the push button is manually reset. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. <First Example> 1 to 8B are diagrams illustrating an emergency stop switch with operation assistance function (hereinafter simply referred to as "emergency stop switch") according to a first embodiment of the present invention. Fig. 1 shows the state of the emergency stop switch before the push button is pressed, Fig. 2 shows the state during manual pressing of the push button, Fig. 3 shows the state after manual pressing of the push button, Fig. 4 shows the state during manual reset of the push button, Fig. 5 shows the state after manual reset of the push button, Fig. 6 shows the state during operation assistance of the push button, and Fig. 7 shows the state after manual reset of the push button from operation assistance. Figs. 8A and 8B are graphs showing the relationship between the first force F1 applied by the first application means and the second force F2 applied by the second application means and the depression stroke of the push button. Roman numerals I to V in Figs. 8A and 8B correspond to the states shown in Figs. 1 to 5, respectively (see Roman numerals I to V at the bottom of Figs. 1 to 5).

[0028] 1 to 7 show a vertical cross section of the emergency stop switch, but for convenience of illustration, hatching representing a cross section is omitted in some parts of each figure (the same applies to the other embodiments described below). downward In this first embodiment, an emergency stop switch is used as an example of an operation switch (the same applies to the other embodiments below).

[0029] As shown in FIG. 1, the emergency stop switch 1 has a push button (operating unit) 2 that can be manually depressed. An operating shaft 3 extending in the axial direction (up and down direction) is disposed below the push button 2. The upper end of the operating shaft 3 is connected to the lower part of the push button 2. The operating shaft 3 is supported inside a housing 10A and a housing 10B that is integrally provided below the housing 10A so as to be movable in the axial direction. A contact (main contact) 11 is provided at the lower end of the operating shaft 3. The contact 11 has a fixed contact 111 and a movable contact 112 that is connected to the lower end of the operating shaft 3 and moves together with the operating shaft 3 to open and close relative to the fixed contact 111.

[0030] Inside the housing 10A, the operating shaft 3 is provided with a flange portion 30 that protrudes from the outer periphery. A compression spring (first acting means) 4 is disposed above the flange portion 30 and around the operating shaft 3. The upper end of the compression spring 4 is in pressure contact with the inner wall surface of the housing 10A, and the lower end is in pressure contact with the flange portion 30. The compression spring 4 exerts an elastic repulsive force downward (i.e., in the direction along the pressing direction of the push button 2) on the operating shaft 3 via the flange portion 30; here, this downward elastic repulsive force of the compression spring 4 is referred to as a first force F1. The first force F1 of the compression spring 4 acts in a direction that opens the contacts 11.

[0031] An electromagnetic solenoid 5 is provided inside the housing 10B. The electromagnetic solenoid 5 has a solenoid body (second operating means) 51 made of a coil. In the internal space of the solenoid body 51, a fixed iron core 52 is fixed to the upper side, and a cylindrical plunger (movable iron core) 53 is disposed on the lower side. The fixed iron core 52 and the plunger 53 are both made of magnetic material and have vertical through holes 52c and 53c, respectively, through which the operating shaft 3 is movably inserted. The fixed iron core 52 has a fixed base 52A fixed to the upper part of the housing 10B and a cylindrical portion 52B extending downward therefrom. The plunger 53 has a recess 53a that opens upward, and the cylindrical portion 52B of the fixed iron core 52 is housed in the recess 53a. An upper end 53b of the plunger 53 is arranged to be able to come into contact with a lower surface 52a of a fixed base 52A of the fixed iron core 52. Note that before the push button 2 shown in Fig. 1 is pressed, a current is supplied to the electromagnetic solenoid 5 and the solenoid body 51 is excited, and to clearly indicate this, the solenoid body 51 is shown in bold in the figure. This method of representation is the same in the following drawings and other embodiments.

[0032] Inside the housing 10B, flanges 31 and 32 are provided on the operating shaft 3, protruding from the outer periphery and spaced apart in the axial direction. The flange 31 is disposed within the recess 53a of the plunger 53, and the flange 32 is disposed below the plunger 53.

[0033] When current is supplied to the electromagnetic solenoid 5 (i.e., energized) and the solenoid body 51 is excited, the solenoid body 51 exerts an upward force on the plunger 53. At this time, an upward force (i.e., in the opposite direction to the downward first force F1 due to the compression spring 4) is acting on the operating shaft 3 from the plunger 53 via the flange portion 31, and here the upward force due to the action of the solenoid body 51 is referred to as the second force F2.

[0034] Next, the effects of this embodiment will be described. 1, before the push button 2 is pressed, the upper end 53b of the plunger 53 abuts against the lower surface 52a of the fixed base 52A of the fixed iron core 52. At this time, as shown by "I" in FIG. 8A, the pressing stroke of the push button 2 is 0 (mm), the first force F1 and the second force F2 are at their maximum, and the magnitude relationship between the first force F1 and the second force F2 is F2>F1 At this time, the contact 11 is in an ON state (first state) with the movable contact 112 in contact with the fixed contact 111 (see FIG. 1).

[0035] The first force F1 is a downward elastic repulsive force of the compression spring 4, and since the length of the compression spring 4 increases as the depression stroke of the push button 2 increases, the first force F1 decreases as the depression stroke of the push button 2 increases (see the straight line graph F1 in FIG. 8A). The second force is an upward force caused by the electromagnetic force of the solenoid body 51 of the electromagnetic solenoid 5, and decreases as the depression stroke of the push button 2 increases (see the curved line graph F2 in the same figure). Therefore, the magnitudes of the first force F1 and the second force F2 are determined according to the depression stroke of the push button 2.

[0036] Next, as shown in FIG. 2, when the operator applies a pressing force F to the push button 2 to press it down, the operating shaft 3 moves downward together with the push button 2.

[0037] At this time, flange portion 31 of operating shaft 3 abuts against the bottom of recess 53a of plunger 53, and plunger 53 acts on operating shaft 3 with a second upward force F2 via flange portion 31. Operating shaft 3 moves downward while resisting second force F2, but as operating shaft 3 moves downward, the depression stroke of push button 2 increases, and so second force F2 gradually decreases, as shown by graph F2 in Fig. 8A.

[0038] Meanwhile, the elastic repulsive force of the compression spring 4 acts on the flange portion 30 of the operating shaft 3, and the operating shaft 3 is subjected to a downward first force F1 from the compression spring 4 via the flange portion 30. The operating shaft 3 moves downward while being subjected to the action of the first force F1, but as the operating shaft 3 moves downward, the depression stroke of the push button 2 increases, and so the first force F1 gradually decreases, as shown by the graph F1 in FIG. 8A.

[0039] In the state in which the push button 2 shown in FIG. 2 is being pressed, a predetermined pressing stroke is generated in the push button 2 as shown by "II" in FIG. 8A. At this time, the magnitude relationship between the first force F1 and the second force F2 is as follows: F1>F2 At this time, the contact 11 is in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 2).

[0040] As described above, according to this embodiment, before the push button 2 is manually pressed, the second force F2 generated by the solenoid body 51 is greater than the first force F1 generated by the compression spring 4, and the contact 11 is in the ON state, and after the push button 2 is manually pressed, the first force F1 generated by the compression spring 4 is greater than the second force F2 generated by the solenoid body 51, and the contact 11 is in the OFF state. Therefore, to manually press the push button 2, it is necessary to apply an external pressing force F to the push button 2 in the pressing direction of the push button 2, which is the direction in which the first force F1 acts. This makes it possible to prevent accidental manual pressing without using a mechanical latch mechanism.

[0041] Next, in the state after the push button 2 is pressed as shown in FIG. 3, as shown in "III" in FIG. 8B (similar to "II" in FIG. 8A), a predetermined pressing stroke is generated in the push button 2, and at this time, the magnitude relationship between the first force F1 and the second force F2 is F1>F2 At this time, the contact 11 is in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 3).

[0042] From this state, as shown in FIG. 4, when the operator applies a pulling force F' to the push button 2 and pulls the push button 2, the operating shaft 3 moves upward together with the push button 2.

[0043] At this time, flange portion 31 of operating shaft 3 abuts against the bottom of recess 53a of plunger 53, and plunger 53 acts on operating shaft 3 with a second upward force F2 via flange portion 31. Operating shaft 3 moves upward while being acted upon by second force F2, but as operating shaft 3 moves upward, the depression stroke of push button 2 becomes smaller, and so second force F2 gradually increases, as shown by graph F2 in FIG. 8B.

[0044] Meanwhile, the elastic repulsive force of the compression spring 4 acts on the flange portion 30 of the operating shaft 3, and the operating shaft 3 is subjected to a downward first force F1 from the compression spring 4 via the flange portion 30. The operating shaft 3 moves upward while resisting the first force F1, but as the operating shaft 3 moves upward, the depression stroke of the push button 2 becomes smaller, and so the first force F1 gradually increases, as shown by the graph F1 in Fig. 8B.

[0045] In the state in which the push button 2 is in the middle of its return movement shown in FIG. 4, as shown by "IV" in FIG. 8B, there is still a pressing stroke remaining in the push button 2, and at this time, the magnitude relationship between the first force F1 and the second force F2 is F1>F2 At this time, the contact 11 is still in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 4).

[0046] When the push button 2 is further pulled from this state to move the operating shaft 3 upward, the push button 2 transitions to the state after the return operation, as shown in Figure 5. At this time, the upper end 53b of the plunger 53 abuts against the lower surface 52a of the fixed base 52A of the fixed iron core 52. As shown by "V" in Figure 8B, the depression stroke of the push button 2 is 0 (mm), the first force F1 and the second force F2 are at their maximum, and the magnitude relationship between the first force F1 and the second force F2 is F2>F1 At this time, the contact 11 is switched to the ON state (first state) with the movable contact 112 in contact with the fixed contact 111 (see FIG. 5).

[0047] As described above, according to this embodiment, before the push button 2 is manually returned to its original position, the first force F1 from the compression spring 4 is greater than the second force F2 from the solenoid body 51, and the contact 11 is in the OFF state, and after the push button 2 is manually returned to its original position, the second force F2 from the solenoid body 51 is greater than the first force F1 from the compression spring 4, and the contact 11 is in the ON state. Therefore, to manually return the push button 2, it is necessary to apply an external tensile force to the push button 2 in the same direction as the second force acts, and this makes it possible to prevent manual return operation from being easily performed without using a mechanical latch mechanism.

[0048] In this way, an emergency stop switch without a mechanical latch mechanism can be realized.

[0049] Next, to assist the operation of the push button 2, the state before the manual operation of the push button 2 shown in FIG. 1 is changed to the state shown in FIG. 6, in which the current supply to the electromagnetic solenoid 5 is stopped and the solenoid body 51 is de-energized.

[0050] Then, the electromagnetic force from the solenoid body 51 no longer acts on the plunger 53, and the second force F2 from the plunger 53 no longer acts on the operating shaft 3. As a result, the only force acting on the operating shaft 3 is the first force F1 from the compression spring 4. The operating shaft 3 moves downward under the action of this first force F1, and the plunger 53 also moves downward accordingly. At this time, the contact 11 is in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 6). Also, at this time, the bottom 53d of the plunger 53 abuts against the flange portion 32 of the operating shaft 3.

[0051] As described above, according to this embodiment, if the current supply to the electromagnetic solenoid 5 is stopped before the push button 2 is manually pressed, the contacts will transition from the ON state to the OFF state, so that even if the worker does not actually press the push button 2 directly, a contact switching operation similar to that performed when the push button is pressed can be easily and safely performed on behalf of the worker, allowing operation assistance to be provided from a location distant from the emergency stop switch 1. In this case, the current supply to the electromagnetic solenoid 5 can be stopped based on an operation assistance signal issued from a location distant from the emergency stop switch 1.

[0052] Furthermore, according to this embodiment, even if a break occurs in the wiring supplying current to the electromagnetic solenoid 5 or if the system experiences a power outage, the current supply to the electromagnetic solenoid 5 will stop and the push button 2 will be in a pressed-in state, making it possible to provide operation assistance more safely, thereby realizing an emergency stop switch with an operation assistance function that takes fail-safe into consideration.

[0053] Next, when current is supplied to the electromagnetic solenoid 5 from the state shown in FIG. 6 to excite the solenoid body 51, the second force F2 acting from the plunger 53 to the operating shaft 3 is restored, as shown in FIG. 7. In this state, when the operator applies an upward pulling force to the push button 2, the push button 2 returns to the state it was in before being pressed (see FIG. 7).

[0054] <Second Example> FIG. 9 is a schematic longitudinal sectional view of the push button portion in the emergency stop switch according to the second embodiment of the present invention. In the figure, the same reference numerals as those in the first embodiment denote the same or corresponding parts.

[0055] As shown in FIG. 9, the upper end of the operating shaft 3 is connected inside the push button 2. The operating shaft 3 is provided with a protruding portion 35 that protrudes from the outer periphery. The protruding portion 35 has a tapered surface 351 disposed on the upper side and a vertical wall surface 352 disposed on the lower side thereof and extending in the vertical direction. On the other hand, on the housing side, a plurality of contact blocks 6 that elastically contact the vertical wall surface 352 of the protruding portion 35 are provided. The contact block 6 is biased toward the protruding portion 35 by the elastic repulsive force of the compression spring 7. The contact block 6 has a contact surface 61 that contacts the vertical wall surface 352 of the protruding portion 35. The contact block 6 and the compression spring 7 are accommodated in a housing portion 12 provided on the housing side, and the contact block 6 is movable in the left-right direction shown in the figure within the housing portion 12. Further, the housing portion 12 has a through hole 12a through which the operating shaft 3 is inserted in the vertical direction. The contact block 6 and the compression spring 7 function as holding means for applying a radial pressing force, that is, a holding force, to the vertical wall surface 352 of the protruding portion 35 of the operating shaft 3.

[0056] When a pressing force from the contact block 6 acts on the vertical wall surface 352 of the protruding portion 35 of the operating shaft 3, a frictional force in the direction opposite to the moving direction of the operating shaft 3 acts on the operating shaft 3 during the pushing operation and the return operation of the push button 2.

[0057] That is, during the pushing operation of the push button 2, the frictional force accompanying the action of the pressing force from the contact block 6 acts upward on the operating shaft 3 and adds to the second force F2. Therefore, in FIG. 8A of the first embodiment, the transition from F2 > F1 to F2 < F1 can be prevented from occurring with a small stroke. As a result, the manual pushing operation of the push button 2 can be prevented from being inadvertently performed. For example, even if vibrations, impacts, or the like act, the push button 2 can be prevented from easily moving in the pushing direction.

[0058] Also, after the push button 2 is pushed in, the contact block 6 is in contact with the tapered surface 351 of the protruding portion 35 of the operating shaft 3. From this state, to perform the return operation of the push button 2, while retracting the contact block 6, the operating shaft 3 needs to be moved upward, and the contact block 6 needs to be brought into contact with the vertical wall surface 352 of the protruding portion 35 of the operating shaft 3 to move the operating shaft 3 upward. At this time, a downward frictional force acts on the operating shaft 3 and adds to the first force F1. Therefore, during the return operation of the push button 2 (i.e., during the movement of the operating shaft 3), in FIG. 8B of the first embodiment, the transition from F1>F2 to F1<F2 can be prevented from occurring with a large stroke. As a result, the manual return operation of the push button 2 can be made difficult to perform. Note that the pressing force (holding force) by the contact block 6 and the compression spring 7 is set to a magnitude that does not interfere with the operation assistance of the push button 2.

[0059] <Third Embodiment> FIGS. 10 to 16 are diagrams for explaining an emergency stop switch with an operation assistance function (emergency stop switch) according to the third embodiment of the present invention. FIG. 10 shows the state before the push button of the emergency stop switch is pushed in, FIG. 11 shows the state during the manual pushing-in operation of the push button, FIG. 12 shows the state after the manual pushing-in operation of the push button, FIG. 13 shows the state during the manual return operation of the push button, FIG. 14 shows the state after the manual return operation of the push button, FIG. 15 shows the state during the operation assistance of the push button, and FIG. 16 shows the state after the manual return operation from the state during the operation assistance of the push button. In these figures, the same reference numerals as those in the first embodiment indicate the same or corresponding parts.

[0060] In this third embodiment, it is different from the first embodiment in that the operating shaft 3 in the first embodiment is composed of two operating shafts 3A and 3B, and a compression spring 8 as the first' acting means is added.

[0061] That is, as shown in FIG. 10, in the emergency stop switch 1, a first operating shaft 3A extending in the axial direction (vertical direction) is disposed below the push button (operating unit) 2. In this example, an operating shaft with a larger diameter than the operating shaft 3 of the first embodiment is used. The upper end of the first operating shaft 3A is connected to the lower part of the push button 2. The first operating shaft 3A is supported inside the housing 10A so as to be movable in the axial direction. A boss portion 30A is provided below the flange portion 30 of the first operating shaft 3A. The boss portion 30A has a diameter larger than the inner diameter of the through-hole 52c of the fixed iron core 52 disposed below it. A first force F1, which is the elastic repulsive force of the compression spring (first acting means) 4, acts downward on the first operating shaft 3A via the flange portion 30.

[0062] Within the housing 10B, a second operating shaft 3B is disposed below the first operating shaft 3A. The second operating shaft 3B extends in the axial direction (vertical direction) and passes through the through-hole 52c of the fixed iron core 52. In the state before the push button 2 is pressed as shown in FIG. 10, the upper end of the second operating shaft 3B extends into the housing 10A and abuts against the lower end of the boss portion 30A of the first operating shaft 3A. The second operating shaft 3B is provided separately from the first operating shaft 3A and is separable from the first operating shaft 3A. The second operating shaft 3B is supported within the housing 10B so as to be movable in the axial direction. A contact (main contact) 11 consisting of a fixed contact 111 and a movable contact 112 is provided at the lower end of the second operating shaft 3B. A second force F2 acts upward on the second operating shaft 3B from the plunger 53 via the flange portion 31 due to the action of the solenoid body (second acting means) 51, which is excited by supplying current to the electromagnetic solenoid 5.

[0063] A compression spring (first' acting means) 8 is disposed around the second operating shaft 3B within the recess 53a of the plunger 53 of the electromagnetic solenoid 5. The upper end of the compression spring 8 is in pressure contact with the lower end of the cylindrical portion 52B of the fixed iron core 52, and the lower end is in pressure contact with the flange portion 31 of the second operating shaft 3B. As a result, a first' force F1', which is the elastic repulsive force of the compression spring 8, acts on the second operating shaft 3B via the flange portion 31 in a downward direction along the pressing direction of the push button 2.

[0064] Next, the effects of this embodiment will be described. In the state before the push button 2 is pressed as shown in FIG. 10, the upper end 53b of the plunger 53 is in contact with the lower surface 52a of the fixed base 52A of the fixed iron core 52, and the first force F1, the first' force F1', and the second force F2 are at their maximum. The magnitude relationship between the resultant force of the first force F1 and the first' force F1' and the second force F2 is as follows: F2>F1+F1' At this time, the contact 11 is in an ON state (first state) with the movable contact 112 in contact with the fixed contact 111 (see FIG. 10).

[0065] Next, as shown in FIG. 11, when the operator applies a pressing force F to the push button 2 to press it down, the first operating shaft 3A moves downward together with the push button 2. A The first operating shaft 3A moves until the lower end of boss portion 30A abuts against the upper surface of fixed base 52A of fixed iron core 52. At this time, the upper end of second operating shaft 3B abuts against the lower end of boss portion 30A of first operating shaft 3A, so second operating shaft 3B moves downward together with first operating shaft 3A. At this time, first operating shaft 3A is acted upon by a first downward force F1 by compression spring 4, while second operating shaft 3B is acted upon by a first downward force F1' by compression spring 8, and moves while resisting a second upward force F2 by the action of solenoid body 51.

[0066] Here, the first force F1 and the first' force F1' are elastic repulsive forces of the compression springs 4 and 8, respectively. Since the lengths of the compression springs 4 and 8 increase as the depression stroke of the push button 2 increases, the first force F1 and the first' force F1' decrease as the depression stroke of the push button 2 increases. The second force is a force caused by the action of the electromagnetic force of the solenoid body 51 of the electromagnetic solenoid 5, and decreases as the depression stroke of the push button 2 increases (see the curved graph F2 in FIG. 8A). Therefore, the magnitudes of the first force F1, the first' force F1', and the second force F2 correspond to the depression stroke of the push button 2.

[0067] In the state in which the push button 2 is being pressed as shown in FIG. 11, the magnitude relationship between the resultant force of the first force F1 and the first force F1' and the second force F2 is as follows: F1+F1'>F2 At this time, the contact 11 is in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 11).

[0068] As described above, according to this embodiment, before the push button 2 is manually pressed, the second force F2 generated by the solenoid body 51 is greater than the resultant force of the first force F1 generated by the compression spring 4 and the first' force F1' generated by the compression spring 8, and the contact 11 is in the ON state, and after the push button 2 is manually pressed, the resultant force of the first force F1 generated by the compression spring 4 and the first' force F1' generated by the compression spring 8 is greater than the second force F2 generated by the solenoid body 51, and the contact 11 is in the OFF state. Therefore, to manually press the push button 2, it is necessary to apply an external pressing force F to the push button 2 in the pressing direction of the push button 2, which is the direction in which the resultant force of the first force F1 and the first' force F1' acts, and this makes it possible to prevent accidental manual pressing without using a mechanical latch mechanism.

[0069] Next, in the state after the push button 2 is pressed as shown in FIG. 12, the magnitude relationship between the resultant force of the first force F1 and the first force F1' and the second force F2 is as follows: F1+F1'>F2 At this time, the contact 11 is in the OFF state (second state) with the movable contact 112 separated from the fixed contact 111 (see FIG. 12).

[0070] 13, when the operator applies a pulling force F' to the push button 2 and pulls it, the first operating shaft 3A moves upward together with the push button 2. Because the upper end of the second operating shaft 3B abuts against the lower end of the boss portion 30A of the first operating shaft 3A, the second operating shaft 3B moves upward together with the first operating shaft 3A. At this time, the first and second operating shafts 3A, 3B move against the downward first force F1 from the compression spring 4 and the downward first force F1' from the compression spring 8 while being acted upon by the upward second force F2 from the solenoid body 51.

[0071] Here, the first force F1 and the first' force F1' are elastic repulsive forces of the compression springs 4 and 8, respectively. Since the lengths of the compression springs 4 and 8 shorten as the depression stroke of the push button 2 decreases, the first force F1 and the first' force F1' increase as the depression stroke of the push button 2 decreases. The second force is a force caused by the action of the electromagnetic force of the solenoid body 51 of the electromagnetic solenoid 5, and increases as the depression stroke of the push button 2 decreases (see the curved graph F2 in FIG. 8B). Therefore, the magnitudes of the first force F1, the first' force F1', and the second force F2 correspond to the depression stroke of the push button 2.

[0072] In the state in which the push button 2 is in the middle of its return operation shown in FIG. 13, the magnitude relationship between the resultant force of the first force F1 and the first force F1' and the second force F2 is F1+F1'>F2 At this time, the movable contact 112 is separated from the fixed contact 111, and the contact 11 is still in the OFF state (second state) (see FIG. 13). If the operator releases the push button 2 while the return operation is in progress, the contact 11 will return to the OFF state (the second state shown in FIG. 12) due to the inequality above.

[0073] When the first and second operating shafts 3A and 3B move further upward together with the push button 2 from this state, the push button 2 transitions to the state after the return operation shown in Figure 14. At this time, the upper end 53b of the plunger 53 abuts against the lower surface 52a of the fixed base 52A of the fixed iron core 52, and the first force F1, the first' force F1', and the second force F2 are at their maximum. In this state, the magnitude relationship between the resultant force of the first force F1 and the first' force F1' and the second force F2 is F2>F1+F1' At this time, the movable contact 112 is in contact with the fixed contact 111, and the contact 11 is switched to the ON state (first state) (see FIG. 14).

[0074] As described above, according to this embodiment, before the push button 2 is manually returned to its original position, the resultant force of the first force F1 from the compression spring 4 and the first' force F1' from the compression spring 8 is greater than the second force F2 caused by the action of the solenoid body 51, and the contact 11 is in the OFF state, and after the push button 2 is manually returned to its original position, the second force F2 caused by the action of the solenoid body 51 is greater than the resultant force of the first force F1 from the compression spring 4 and the first' force F1' from the compression spring 8, and the contact 11 is in the ON state. Therefore, to manually return the push button 2, it is necessary to apply an external tensile force to the push button 2 in the same direction as the acting direction of the second force, which makes it possible to prevent manual return from being easily performed without using a mechanical latch mechanism.

[0075] In this way, an emergency stop switch without a mechanical latch mechanism can be realized.

[0076] Next, to assist in the operation of the push button 2, the state before the manual operation of the push button 2 shown in FIG. 10 is changed to the state shown in FIG. 15, where the current supply to the electromagnetic solenoid 5 is stopped and the solenoid body 51 is de-energized.

[0077] Then, the electromagnetic force from the solenoid body 51 no longer acts on the plunger 53, and the second force F2 from the plunger 53 no longer acts on the second operating shaft 3B. As a result, the only force acting on the second operating shaft 3B is the first force F1' from the compression spring 8. The second operating shaft 3B moves downward under the action of this first force F1', and the plunger 53 also moves downward. Because the downward first force F1 from the compression spring 4 acts on the first operating shaft 3A, the first operating shaft 3A moves downward together with the second operating shaft 3B. At this time, the movable contact 112 is separated from the fixed contact 111, and the contact 11 is switched to the OFF state (second state) (see Figure 15). At this time, the bottom 53d of the plunger 53 abuts against the flange portion 32 of the operating shaft 3.

[0078] As described above, according to this embodiment, if the current supply to the electromagnetic solenoid 5 is stopped before the push button 2 is manually pressed, the contacts will transition from the ON state to the OFF state, so that even if the worker does not actually press the push button 2 directly, a contact switching operation similar to that performed when the push button is pressed can be easily and safely performed on behalf of the worker, allowing operation assistance to be provided from a location distant from the emergency stop switch 1. In this case, the current supply to the electromagnetic solenoid 5 can be stopped based on an operation assistance signal issued from a location distant from the emergency stop switch 1.

[0079] Furthermore, according to this embodiment, even if a break occurs in the wiring supplying current to the electromagnetic solenoid 5 or if the system experiences a power outage, the current supply to the electromagnetic solenoid 5 will stop and the push button 2 will be in a pressed-in state, making it possible to provide operation assistance more safely, thereby realizing an emergency stop switch with an operation assistance function that takes fail-safe into consideration.

[0080] Next, when current is supplied to the electromagnetic solenoid 5 from the state shown in FIG. 15 to excite the solenoid body 51, the second force F2 acting from the plunger 53 to the second operating shaft 3B is restored, as shown in FIG. 16. In this state, when the operator applies an upward pulling force to the push button 2, the push button 2 returns to the state it was in before being pressed.

[0081] <Fourth Example> 17 to 20 are diagrams illustrating an emergency stop switch with operation assistance function (emergency stop switch) according to a fourth embodiment of the present invention. Fig. 17 shows the state before the push button of the emergency stop switch is pressed, Fig. 18 shows the state when the push button is manually pressed, Fig. 19 shows the state when operation assistance is provided for the push button, and Fig. 20 shows the state after manual reset operation from the operation assistance for the push button. In these figures, the same reference numerals as those in the third embodiment indicate the same or corresponding parts.

[0082] The fourth embodiment differs from the third embodiment in that a monitor contact (detector) 15 is provided at the lower end of the second operating shaft 3B. The monitor contact 15 detects, by movement of the second operating shaft 3B, changes in the state of the contact (main contact) caused by the push button 2 being pressed, the completion of the return operation of the push button 2, and the operation of the emergency stop switch 1 being assisted, and has a fixed contact 151 and a movable contact 152 that is connected to the second operating shaft 3B and moves together with the second operating shaft 3B to open and close relative to the fixed contact 151. The drive of the electromagnetic solenoid 5 is controlled based on a signal from the monitor contact 15.

[0083] Next, the effects of this embodiment will be described. In the state before the push button 2 is pressed as shown in FIG. 17, the contact (main contact) 11 is in an ON state (first state) with the movable contact 112 in contact with the fixed contact 111, and the monitor contact 15 is in an OFF state with the movable contact 152 separated from the fixed contact 151. (See Figure 17).

[0084] Next, as shown in Figure 18, when the operator applies a pressing force F to the push button 2 to press it in, the first operating shaft 3A moves downward together with the push button 2. Because the upper end of the second operating shaft 3B abuts against the lower end of the boss portion 30A of the first operating shaft 3A, the second operating shaft 3B moves downward together with the first operating shaft 3A. At this time, the movable contact 112 of the contact 11 is separated from the fixed contact 111, and the contact 11 switches to the OFF state (second state), and the movable contact 152 of the monitor contact 15 comes into contact with the fixed contact 151, and the monitor contact 15 switches to the ON state (see Figure 18).

[0085] 19, based on the contact signal of the monitor contact 15, the current supply to the electromagnetic solenoid 5 is stopped and the solenoid body 51 is de-energized. Then, the electromagnetic force from the solenoid body 51 no longer acts on the plunger 53, and the second force F2 from the plunger 53 no longer acts on the second operating shaft 3B. As a result, the only force acting on the second operating shaft 3B is the first force F1' from the compression spring 8.

[0086] 20, when the operator applies a pulling force F' to the push button 2 and pulls it, the push button 2 moves upward and the first operating shaft 3A also moves upward, but at this time, the second operating shaft 3B is not receiving the second force F2 from the plunger 53, so the second operating shaft 3B cannot follow the upward movement of the first operating shaft 3A and is separated from the first operating shaft 3A and remains inside the housing 10 (see FIG. 20). As a result, as shown in FIG. 20, the contact 11 remains in the OFF state (second state) in which the movable contact 112 is separated from the fixed contact 111.

[0087] The state shown in FIG. 19 is similar to the state shown in FIG. 15, which shows the state in the third embodiment where operational assistance has been provided before the push button 2 is pressed (therefore, the provision of operational assistance can also be detected by the monitor contact 15). Therefore, when the push button 2 is returned to its original position after the solenoid body 51 is de-energized, the second operating shaft 3B does not follow the upward movement of the first operating shaft 3A but remains inside the housing 10, leaving the contact 11 in the OFF state. This occurs not only after the push button 2 is manually pressed, but also after operational assistance has been provided for the push button 2.

[0088] In cases where the operating shaft is made up of a first operating shaft 3A and a separable second operating shaft 3B, as in the third and fourth embodiments, if no current is supplied to the electromagnetic solenoid 5, the contact 11 cannot be turned ON (i.e., the emergency stop state cannot be reset) even if the push button 2 is manually reset. In other words, the emergency stop state cannot be reset unless the two conditions of the manual reset operation of the push button 2 and the supply of current to the electromagnetic solenoid 5 are met. This improves the safety of the emergency stop switch and is expected to prevent accidents.

[0089] <Fifth Example> In the first embodiment, an example was shown in which current is constantly supplied to the electromagnetic solenoid 5 except when assisting the operation of the push button 2, but the application of the present invention is not limited to this. Current may be supplied to the electromagnetic solenoid 5 at least when the contact 1 is in the ON state (i.e., the first state, i.e., the state before the push button 2 is pressed).

[0090] <Sixth Example> In the first embodiment, the current supply to the electromagnetic solenoid 5 is stopped when assisting the operation of the push button 2, but the application of the present invention is not limited to this. The current supplied to the electromagnetic solenoid 5 may be limited to reduce the second force F2 acting on the operating shaft 3 from the plunger 53, thereby making the relational expression F1>F2 valid.

[0091] <Seventh Example> In each of the above-described embodiments, after the current supply to the electromagnetic solenoid 5 is stopped and operation of the push button 2 is assisted, a signal such as an RFID (Radio Frequency Identification) signal may be used as a signal to allow the current supply to the electromagnetic solenoid 5 again. In this case, after the worker has performed an emergency stop and confirmed the safety of the device, the RF tag carried by each worker may be read by a tag reader.

[0092] <Eighth Example> In each of the above-described embodiments, the solenoid body 51 of the electromagnetic solenoid 5 is used as the second operating means according to the present invention, but the application of the present invention is not limited to this. Instead of the electromagnetic solenoid 5, a cylinder, a motor, or other (electric / electrically-driven) actuator may be used.

[0093] Even in this case, if a break (fault) occurs in the wiring (path) for supplying power to the (electric / electric) actuator, or if the system experiences a power outage, the power supply to the (electric / electric) actuator will be stopped, causing push button 2 to be pressed in, allowing for safer operation assistance, thereby realizing an emergency stop switch with an operation assistance function that takes fail-safe into consideration.

[0094] <Tenth Example> In each of the above-described embodiments, an example has been shown in which a compression spring 4 is used as the elastic member, but an elastic member such as a tension (coil) spring, a torsion (coil) spring, or a leaf spring may be used instead of the compression spring 4. The tension spring is disposed, for example, below the flange portion 30 of the operating shaft 3, and applies a first downward force F to the operating shaft 3.

[0095] <Eleventh Example> The ON / OFF state of the monitor contact 15 in the fourth embodiment may be reversed. That is, the monitor contact may be set to ON before the push button 2 is pressed, and may be set to OFF after the push button 2 is manually pressed or after operation assistance is provided.

[0096] [Other Modifications] The above-described embodiments are to be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains will be able to devise various modifications and other embodiments that incorporate the principles of the present invention, even if not expressly described herein, without departing from the spirit and essential characteristics thereof, when taking into account the teachings set forth above.

[0097] [Other application examples] In each of the above embodiments, an emergency stop switch has been described as an example of an operation switch according to the present invention, but the application of the present invention is not limited to this, and the present invention can also be applied to push button switches other than emergency stop switches. [Industrial Applicability]

[0098] INDUSTRIAL APPLICABILITY The present invention is useful for an operation switch with an operation assist function, an emergency stop switch with an operation assist function, and an operation switch that have an operation portion that can be manually pressed. [Explanation of symbols]

[0099] 1: Emergency stop switch with operation support function (operation switch with operation support function) 2: Push button (operation part) 3: Operation axis 3A: First operating axis 3B: Second axis of action 4: Compression spring (first acting means) 5: Electromagnetic solenoid 51: Solenoid body (second acting means) 6, 7: Retention means 8: Compression spring (first' action means) 11: Contact 15: Monitor contact (detection part) F1: First Force F1': First Force F2: Second Power [Prior art documents] [Patent documents]

[0100] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-35302 (see FIG. 1)

Claims

1. Emergency stop switches with operation support functions A push button that can be pressed manually or with operation assistance; an operating shaft connected to the push button for switching the contact; a first applying means for applying a first force to the operating shaft in a pressing direction of the push button; a second acting means for applying a second force to the operating shaft in a direction opposite to the direction of application of the first force by the first acting means, before the push button is manually or by operation assistance, the second force applied by the second applying means is greater than the first force applied by the first applying means, and the contacts are in a first state; after the push button is manually pressed and after operation assistance of the push button is performed, the first force applied by the first applying means is greater than the second force applied by the second applying means, and the contacts are in a second state different from the first state; the second acting means is an actuator, and the actuator acts on the operating shaft when energized, at least in the first state; An emergency stop switch with an operation support function.

2. In claim 1, the first acting means is an elastic member; An emergency stop switch with an operation support function.

3. In claim 1, The first actuating means is a compression spring, and the second actuating means is an electromagnetic solenoid. An emergency stop switch with an operation support function.

4. In claim 1, Further comprising a detection unit that detects a change in the state of the contact. An emergency stop switch with an operation support function.

5. In claim 1, Further provided is a holding means for applying a holding force to the operating shaft from the outer circumferential side. An emergency stop switch with an operation support function.

Images