JP7764566B2 - Operation switch with operation support function, emergency stop switch with operation support function and operation switch - Google Patents

Description

The present invention relates to an operation switch with an operation assistance function that has an operating section that can be manually pressed, an emergency stop switch with an operation assistance function, and an operation switch.

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.

When the emergency stop switch's push button is not 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 force strong enough to overcome the holding force of this mechanical latch mechanism.

Furthermore, with emergency stop switches, the operator must be very close to the switch when pressing the push button; they cannot be operated from a distance. As a result, there was a demand for an emergency stop switch with an operation assistance function that would allow for safer operation assistance even from a distance.

The present invention was made in consideration of these conventional circumstances, 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.

The emergency stop switch with operation assistance function according to the present invention includes 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 is 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 the second force to the operating shaft when energized, at least in the first state.

According to the present invention, before the push button is manually or assistedly depressed, 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 depressed or assisted, 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 applying means is an actuator, and the actuator applies the second force to the operating shaft when energized, at least in the first state. Therefore, to manually depress the push button, an external pressing force must be applied in the direction of depression of the push button, which is the direction of application of the first force. This prevents accidental manual depression without using a mechanical latch mechanism. Furthermore, to manually reset the push button, an external pulling force must be applied to the push button in the same direction as the direction of application of the second force. This prevents easy manual reset without using a mechanical latch mechanism. In this way, an emergency stop switch with an operation support function that does not have a mechanical latch mechanism can be realized.

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

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

In the present invention, the first actuating means is a compression spring and the second actuating means is an electromagnetic solenoid.

The present invention further includes a detection unit that detects changes in the state of the contacts.

The present invention further includes a holding means that applies a holding force to the operating shaft from the outer periphery.

As described above, according to the present invention, not only can an emergency stop switch without a mechanical latch mechanism be realized, but also safer operation assistance can be easily provided with fail-safe measures taken into consideration.

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. FIG. 1 shows the state of the emergency stop switch (FIG. 1) when the push button is manually pressed. 1 shows the state of the emergency stop switch (FIG. 1) after the push button has been manually pressed. This shows the emergency stop switch (FIG. 1) in the middle of a manual reset operation of the push button. 1 shows the state of the emergency stop switch (FIG. 1) after the push button has been manually reset. This shows the state of the emergency stop switch (FIG. 1) when assisting the operation of the push button. 1 shows the state of the emergency stop switch (FIG. 1) after a recovery operation from the push button operation support. 1 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 (FIG. 1), showing the change when the push button is manually depressed. 1 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 (FIG. 1), and shows the change during a manual return operation of the push button. 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. 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 a push button is pressed. This shows the state of the emergency stop switch (FIG. 10) when the push button is manually pressed. This shows the state of the emergency stop switch (FIG. 10) after the push button has been manually pressed. This shows the state of the emergency stop switch (FIG. 10) when the push button is manually reset. This shows the state of the emergency stop switch (FIG. 10) after the push button has been manually reset. This shows the state of the emergency stop switch (FIG. 10) when assisting the operation of the push button. This shows the state of the emergency stop switch (FIG. 10) after the return operation from the push button operation support. 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 a push button is pressed. This shows the state of the emergency stop switch (FIG. 17) when the push button is manually pressed. In the emergency stop switch (FIG. 17), the state in which the electromagnetic solenoid is turned off after the push button is manually pressed is shown. This shows the state of the emergency stop switch (FIG. 19) when the push button is manually reset.

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 an operation assistance function (hereinafter simply referred to as the "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).

1 to 7 show a vertical cross section of an 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 below). Also, for convenience of explanation, the up-down direction in each figure will be referred to as the up-down direction. 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).

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) 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 so as to be movable in the axial direction within a housing 10A and a housing 10B that is integrally formed below the housing 10A. 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 .

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 a downward elastic repulsive force (i.e., in the direction along which the push button 2 is pressed) 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 the first force F1. The first force F1 of the compression spring 4 acts in a direction that opens the contacts 11.

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. Within 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 below. Both the fixed iron core 52 and the plunger 53 are 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 top of the housing 10B and a cylindrical portion 52B extending downward. The plunger 53 has a recess 53a opening upward, and the cylindrical portion 52B of the fixed iron core 52 is housed within the recess 53a. The upper end 53b of the plunger 53 is capable of abutting against the lower surface 52a of the fixed base 52A of the fixed iron core 52. Note that before the push button 2 shown in Figure 1 is pressed, current is supplied to the electromagnetic solenoid 5, and the solenoid body 51 is excited; 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 figures and other embodiments.

Inside the housing 10B, the operating shaft 3 has flanges 31 and 32 that protrude from the outer periphery and are spaced apart in the axial direction. Flange 31 is located within the recess 53a of the plunger 53, and flange 32 is located below the plunger 53.

When current is supplied to the electromagnetic solenoid 5 (i.e., when it is 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 is acting on the operating shaft 3 from the plunger 53 via the flange portion 31 (i.e., in the opposite direction to the downward first force F1 acting from the compression spring 4); here, the upward force acting from the solenoid body 51 is referred to as the second force F2.

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 the ON state (first state) with the movable contact ₁₁₂ in contact with the fixed contact ₁₁₁ (see FIG. 1).

The first force F1 is the downward elastic repulsive force of the compression spring 4. Because 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 linear graph F1 in Figure 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 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.

Next, as shown in Figure 2, when the operator applies a pressing force F to the push button 2, the operating shaft 3 moves downward along with the push button 2.

At this time, the flange portion 31 of the operating shaft 3 abuts against the bottom of the recess 53a of the plunger 53, and the operating shaft 3 is subjected to an upward second force F2 from the plunger 53 via the flange portion 31. The operating shaft 3 moves downward while resisting this second force F2, but as the operating shaft 3 moves downward, the depression stroke of the push button 2 increases, and so the second force F2 gradually decreases, as shown by graph F2 in Figure 8A.

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 Figure 8A.

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 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).

As described above, according to this embodiment, before the push button 2 is manually depressed, 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. After the push button 2 is manually depressed, 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 depress the push button 2, an external pressing force F must be applied to the push button 2 in the direction in which the first force F1 acts, i.e., the pushing direction of the push button 2. This prevents accidental manual depression without the need for a mechanical latch mechanism.

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).

From this state, as shown in Figure 4, when the operator applies a pulling force F' to the push button 2 and pulls it, the operating shaft 3 moves upward along with the push button 2.

At this time, the flange portion 31 of the operating shaft 3 abuts against the bottom of the recess 53a of the plunger 53, and the operating shaft 3 is subjected to an upward second force F2 from the plunger 53 via the flange portion 31. The operating shaft 3 moves upward while being subjected to the action of the second force F2, but as the operating shaft 3 moves upward, the depression stroke of the push button 2 becomes smaller, and so the second force F2 gradually increases, as shown by graph F2 in Figure 8B.

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 against 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 graph F1 in Figure 8B.

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).

If 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).

As described above, according to this embodiment, before the push button 2 is manually reset, 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. After the push button 2 is manually reset, 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 reset the push button 2, an external tensile force must be applied to the push button 2 in the same direction as the second force. This makes it possible to prevent manual resetting without using a mechanical latch mechanism.

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

Next, to assist the operation of the push button 2, from the state before manual operation of the push button 2 shown in Figure 1, the current supply to the electromagnetic solenoid 5 is stopped and the solenoid body 51 is de-energized, as shown in Figure 6.

As a result, 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.

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. This means that even if the operator does not actually press the push button 2 directly, the same contact switching operation as if the push button 2 had been pressed can be easily and safely performed on behalf of the operator, 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.

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 is stopped, causing the push button 2 to return to a pressed-in state, allowing for safer operation assistance. This makes it possible to realize an emergency stop switch with an operation assistance function that takes fail-safe measures into consideration.

Next, when current is supplied to the electromagnetic solenoid 5 from the state shown in Figure 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 Figure 7. In this state, if the operator applies an upward pulling force to the push button 2, the push button 2 will return to the state it was in before it was pressed (see Figure 7).

Second Example
9 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, in which the same reference numerals as those in the first embodiment denote the same or corresponding parts.

As shown in FIG. 9 , the upper end of the operating shaft 3 is connected to the inside of the push button 2. The operating shaft 3 has a protruding portion 35 protruding from its outer periphery. The protruding portion 35 has a tapered surface ₃₅₁ disposed on its upper side and a vertically extending vertical wall surface ₃₅₂ disposed below it. Meanwhile, a plurality of abutment blocks 6 are provided on the housing side, elastically abutting against the vertical wall surface ₃₅₂ of the protruding portion 35. The abutment blocks 6 are biased toward the protruding portion 35 by the elastic repulsive force of compression springs 7. The abutment blocks 6 have abutment surfaces ₆₁ that abut against the vertical wall surface ₃₅₂ of the protruding portion 35. The abutment blocks 6 and the compression springs 7 are housed in a housing 12 provided on the housing side, and the abutment blocks 6 are movable in the left-right direction within the housing 12 as shown in the figure. The housing 12 also 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 a holding means for applying a pressing force, that is, a holding force, in the radial direction to the vertical wall surface ₃₅₂ of the protruding portion 35 of the operating shaft 3 .

Since a pressing force from the abutment block 6 acts on the upright wall surface ₃₅₂ of the protrusion 35 of the operating shaft 3, a frictional force in the opposite direction to the movement direction of the operating shaft 3 acts on the operating shaft 3 when the push button 2 is pressed and when it is returned to its original position.

In other words, when the push button 2 is pressed, the frictional force caused by the pressing force from the contact block 6 acts upward on the operating shaft 3 and contributes to the second force F2. This prevents the transition from F2 > F1 to F2 < F1 in a small stroke, as shown in Figure 8A of the first embodiment. This prevents the push button 2 from being manually pressed inadvertently. For example, the push button 2 can be prevented from easily moving in the pressing direction even when subjected to vibrations or impacts.

Furthermore, after the push button 2 is pressed, the abutment block 6 abuts against the tapered surface _35-1 of the protrusion 35 of the operating shaft 3. To return the push button 2 from this state, the operating shaft 3 must be moved upward while the abutment block 6 is retracted, and the operating shaft 3 must be moved upward by abutting the abutment block 6 against the vertical wall surface _35-2 of the protrusion 35 of the operating shaft 3. At this time, a downward frictional force acts on the operating shaft 3, contributing 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), the transition from F1 > F2 to F1 < F2 in FIG. 8B of the first embodiment is prevented from occurring with a large stroke. This prevents the push button 2 from being easily returned manually. The pressing force (holding force) provided by the abutment block 6 and compression spring 7 is set to a magnitude that does not interfere with the operation assistance of the push button 2.

<Third Example>
10 to 16 are diagrams illustrating an emergency stop switch with an operation assistance function (emergency stop switch) according to a third embodiment of the present invention. Fig. 10 shows the state before the push button of the emergency stop switch is pressed, Fig. 11 shows the state when the push button is manually pressed, Fig. 12 shows the state after the push button is manually pressed, Fig. 13 shows the state when the push button is manually reset, Fig. 14 shows the state after the push button is manually reset, Fig. 15 shows the state when the push button is being assisted for operation, and Fig. 16 shows the state after the manual reset from the assisted push button operation. In these figures, the same reference numerals as in the first embodiment indicate the same or corresponding parts.

This third embodiment differs from the first embodiment in that the operating shaft 3 in the first embodiment is composed of two operating shafts 3A and 3B, and in that a compression spring 8 has been added as the first' operating means.

That is, as shown in FIG. 10, in the emergency stop switch 1, a first operating shaft 3A extending in the axial direction (up and down) 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 that it can move axially. 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 located 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.

Within the housing 10B, a second operating shaft 3B is disposed below the first operating shaft 3A, extending in the axial direction (vertical direction) and passing 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.

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, the 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 in line with the pressing direction of the push button 2.

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, the first force F1, the first' force F1', and the second force F2 are at their maximum, and 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 contact 11 is in the ON state (first state) with the movable contact ₁₁₂ in contact with the fixed contact ₁₁₁ (see FIG. 10).

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

Here, first force F1 and first' force F1' are the elastic repulsive forces of compression springs 4 and 8, respectively. Because the length of compression springs 4 and 8 increases as the depression stroke of push button 2 increases, first force F1 and first' force F1' decrease as the depression stroke of push button 2 increases. Furthermore, second force F1 is a force resulting from the action of the electromagnetic force of solenoid body 51 of electromagnetic solenoid 5, and decreases as the depression stroke of push button 2 increases (see curved graph F2 in Figure 8A). Therefore, first force F1, first' force F1', and second force F2 have magnitudes that correspond to the depression stroke of push button 2.

In the state in which the push button 2 is 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 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).

As described above, according to this embodiment, before the push button 2 is manually depressed, 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. After the push button 2 is manually depressed, 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 depress the push button 2, an external pressing force F must be applied 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. This prevents accidental manual depression without the need for a mechanical latch mechanism.

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 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).

From this state, as shown in Figure 13, when the operator applies a pulling force F' to the push button 2 and pulls it, the first operating shaft 3A moves upward along 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 and 3B are subjected to the action of the upward second force F2 from the solenoid body 51, while moving against the downward first force F1 from the compression spring 4 and the downward first force F1' from the compression spring 8.

Here, first force F1 and first' force F1' are elastic repulsive forces from compression springs 4 and 8, respectively. Because the lengths of compression springs 4 and 8 shorten as the depression stroke of push button 2 decreases, first force F1 and first' force F1' increase as the depression stroke of push button 2 decreases. Furthermore, second force F1 is a force resulting from the action of the electromagnetic force of solenoid body 51 of electromagnetic solenoid 5, and increases as the depression stroke of push button 2 decreases (see curved graph F2 in Figure 8B). Therefore, first force F1, first' force F1', and second force F2 have magnitudes that correspond to the depression stroke of push button 2.

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 during this reset operation, the contact 11 will return to the OFF state (second state shown in FIG. 12) due to the inequality above.

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).

As described above, according to this embodiment, before the push button 2 is manually reset, 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 from the action of the solenoid body 51, and the contact 11 is in the OFF state. After the push button 2 is manually reset, the second force F2 from 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 reset the push button 2, an external tensile force must be applied to the push button 2 in the same direction as the second force. This makes it possible to prevent manual resetting without using a mechanical latch mechanism.

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

Next, to assist in the operation of the push button 2, from the state before manual operation of the push button 2 shown in Figure 10, the current supply to the electromagnetic solenoid 5 is stopped and the solenoid body 51 is de-energized as shown in Figure 15.

As a result, the plunger 53 is no longer subjected to the electromagnetic force from the solenoid body 51, 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 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 FIG. 15). At this time, the bottom 53d of the plunger 53 abuts against the flange portion 32 of the operating shaft 3.

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. This means that even if the operator does not actually press the push button 2 directly, the same contact switching operation as if the push button 2 had been pressed can be easily and safely performed on behalf of the operator, 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.

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 is stopped, causing the push button 2 to return to a pressed-in state, allowing for safer operation assistance. This makes it possible to realize an emergency stop switch with an operation assistance function that takes fail-safe measures into consideration.

Next, when current is supplied to the electromagnetic solenoid 5 from the state shown in Figure 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 Figure 16. In this state, if the operator applies an upward pulling force to the push button 2, the push button 2 will return to the state it was in before it was pressed.

<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 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.

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 operation of the push button 2, the completion of the return operation of the push button 2, and the operation support of the emergency stop switch 1, 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.

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 the ON state (first state) with the movable contact ₁₁₂ in contact with the fixed contact ₁₁₁ , and the monitor contact 15 is in the OFF state with the movable contact ₁₅₂ separated from the fixed contact ₁₅₁ (see FIG. 17).

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 contact 11 switches to the OFF state (second state) with the movable contact ₁₁₂ separated from the fixed contact ₁₁₁ , and the monitor contact 15 switches to the ON state with the movable contact ₁₅₂ contacting the fixed contact ₁₅₁ (see Figure 18).

Based on the contact signal from the monitor contact 15, as shown in Figure 19, the current supply to the electromagnetic solenoid 5 is stopped, de-energizing the solenoid body 51. This eliminates the electromagnetic force acting on the plunger 53 from the solenoid body 51, 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.

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 .

The state shown in Figure 19 is similar to the state shown in Figure 15, which shows the state in the third embodiment where operational assistance is provided before the push button 2 is pressed (and 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 is provided for the push button 2.

When the operating shaft is composed 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 manual reset of the push button 2 and power being supplied to the electromagnetic solenoid 5 are met. This improves the safety of the emergency stop switch and is expected to prevent accidents.

Fifth Example
In the first embodiment, an example was shown in which current was 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).

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.

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.

Eighth Example
In 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-operated) actuator may be used.

Even in this case, if a break (fault) occurs in the wiring (path) 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 the push button 2 to enter a pressed-in state, allowing for safer operation assistance, thereby realizing an emergency stop switch with an operation assistance function that takes fail-safe into consideration.

<Tenth Example>
In the above-described embodiments, an example has been shown in which the 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.

<Eleventh Example>
The ON/OFF state of the monitor contact 15 in the fourth embodiment may be reversed, i.e., the monitor contact may be turned ON before the push button 2 is pressed, and may be turned OFF after the push button 2 is manually pressed or after operation assistance is provided.

[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.

[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.

The present invention is useful for operation switches with operation assistance functions that have an operating section that can be manually depressed, emergency stop switches with operation assistance functions, and operation switches.

1: Emergency stop switch with operation support function (operation switch with operation support function)

2: Push button (operation part)

3: Operating shaft 3A: First operating shaft 3B: Second operating shaft

4: Compression spring (first acting means)

5: Electromagnetic solenoid 51: Solenoid body (second acting means)

6, 7: Holding means

8: Compression spring (first' acting means)

11: Contact point

15: Monitor contact (detection part)

F1: First force F1': First' force F2: Second force

Japanese Patent Application Laid-Open No. 2001-35302 (see FIG. 1)

Claims (5)

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