Switch device

Abstract

A switch device includes an operation unit having a pushbutton for performing a pushing operation; a switch unit separably joined to the operation unit, the switch unit including an opening-closing contact mechanism opened or closed in conjunction with the pushing operation of the pushbutton of the operation unit, and a rotary drive plate rotating between a standby position and a usage position; and an engagement portion engaging the operation unit to the rotary drive plate to rotary-drive the rotary drive plate from the standby position to the usage position when the operation unit is attached to the switch unit. The operation unit is detached from or attached to the switch unit to set the opening-closing contact mechanism in respectively predetermined opening-closing states.

Claims

1. A switch device comprising: an operation unit having a pushbutton for performing a pushing operation; a switch unit detachably attached to the operation unit, the switch unit including an opening-closing contact mechanism opened or closed in conjunction with the pushing operation of the pushbutton of the operation unit, and a rotary drive plate rotating between a standby position and a usage position; and an engagement portion provided at the operation unit, the engagement portion engaging the operation unit to the rotary drive plate to rotary-drive the rotary drive plate from the standby position to the usage position when the operation unit is attached to the switch unit, wherein the rotary drive plate is arranged so that in the standby position, the rotary drive plate drives the opening-closing contact mechanism to be in an opening-closing state where the operation unit is in an operation state, and in the usage position, the rotary drive plate drives the opening-closing contact mechanism to be in the opening-closing state where the operation unit is in a standby state, and the operation unit is detached from or attached to the switch unit to set the opening-closing contact mechanism in respectively predetermined opening-closing states.

2. The switch device according to claim 1, wherein the opening-closing contact mechanism includes a contact spring urging an opening-closing contact of the opening-closing contact mechanism in a direction to be in the opening-closing state where the operation unit is in the standby state.

3. The switch device according to claim 1, wherein the rotary drive plate includes a cam piece at one end thereof driving the opening-closing contact mechanism.

4. The switch device according to claim 1, wherein the rotary drive plate of the switch unit includes a return spring returning the rotary drive plate from the usage position to the standby position when the switch unit is separated from the operation unit.

5. The switch device according to claim 1, wherein the engagement portion engaging the operation unit to the rotary drive plate includes an engagement groove provided at the operation unit or the rotary drive plate and inclined in an axial direction, and an engagement protrusion provided at the rotary drive plate or the operation unit to engage the engagement groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a partially cut-out perspective view illustrating the entire structure of the switch device of a present embodiment.

(2) FIG. 2(a), 2(b) depict the structure of the pushbutton portion of the present embodiment, wherein FIG. 2(a) is a partially cut-out exploded perspective view and FIG. 2(b) is a partially cut-out perspective view of the assembled state.

(3) FIG. 3 is a partially cut-out exploded perspective view of the structure of the operation unit main body of the present embodiment.

(4) FIG. 4 is a partially cut-out exploded perspective view of the structure of the operation unit of the present embodiment.

(5) FIG. 5(a), 5(b) illustrate the operation of the operation unit of the present embodiment, wherein FIG. 5(a) is a partially cut-out perspective view illustrating the locked state at the standby position, and FIG. 5(b) is a partially cut-out perspective view illustrating the locked state at the pushing operation position.

(6) FIG. 6 is an exploded perspective view of the switch device of the present embodiment.

(7) FIG. 7 is an exploded perspective view of the switch unit of the switch device of present embodiment.

(8) FIG. 8 is a front view of the rotary drive plate used in the switch device of the present embodiment.

(9) FIGS. 9(a)-9(d) illustrate the process of joining the operation unit and switch unit of the switch device of the present embodiment.

(10) FIG. 10(a), 10(b) illustrate the joined state of the operation unit and switch unit of the switch device of the present embodiment, wherein FIG. 10(a) depicts the state in which the operation unit and switch unit are separated, and FIG. 10(b) depicts the state in which the operation unit and switch unit are joined together.

(11) FIG. 11 is a partially cut-out perspective view illustrating the operation state of the switch device of the present embodiment.

(12) FIG. 12 is a diagram of the conventional switch device.

(13) FIG. 13(a), 13(b) are explanatory drawings of the operation state of the conventional switch device.

(14) FIG. 14 is a diagram illustrating the operation unit of the conventional switch device.

DETAILED DESCRIPTION OF THE INVENTION

(15) An embodiment of the invention will be explained hereinbelow in detail with reference to the drawings.

(16) FIGS. 1 to 11 depict an example of the switch device to be used as a pushbutton switch for emergency stop in accordance with the present embodiment.

(17) In FIG. 1, the reference numeral 1 refers to a switch device provided with an operation unit 10 and a switch unit 20 which are arranged to be joinable to each other and separable from each other.

(18) The operation unit 10 transmits an external operating force to the switch unit 20 and opens/closes an opening/closing contact mechanism located inside the switch unit 20. The operation unit includes a pushbutton 12 and an operation unit main body 11 that supports the pushbutton.

(19) As shown in detail in FIG. 2, the pushbutton 12 is assembled with a push rod 13 through a pushbutton return spring 14 constituted by a twisted coil spring.

(20) When the aforementioned components are assembled, initially, a bent portion 14a at one end of the return spring 14 is inserted in and engaged with an engagement groove 12b of the pushbutton 12. A distal end portion of the push rod 13 is inserted into the spring 14 engaged with the pushbutton 12, and a bent portion 14b at the other end of the spring 14 is inserted in and engaged with a fixing hole 13e of the push rod 13. In this state, the pushbutton 12 is rotated rightward, a pair of engagement protrusions 12c located inside the pushbutton 12 is aligned with a pair of L-shaped engagement grooves 13d on the outer circumference of the distal end portion of the push rod 13, and then the push rod 13 is inserted into the pushbutton 12, and the engagement protrusions 12c and the engagement grooves 13d are engaged with each other. As a result, the pushbutton 12 and the push rod 13 are joined through the return spring 14 so as to be rotatable relative to each other within a predetermined angular range, as depicted in FIG. 2(b).

(21) The operation unit 10 is formed by joining the operation unit main body 11 to the pushbutton 12 of the above-described structure. As shown in detail in FIG. 3, a lock holder 17 provided with a pair of holding grooves 17b is inserted into the operation unit main body 11. A lock pin 15 and a lock spring 16 are inserted into the respective holding grooves 17b of the lock holder 17 and held therein. The lock holder 17 inserted into the operation unit main body 11 is pushed in until the engagement protrusion 17a is engaged with an engagement hole 11h provided in the inner wall of a cylindrical upper body portion 11 of the operation unit main body 11, thereby fixing the lock holder 17 to the operation unit main body 11. The lock pin 15 held in the lock holder 17 which has been fixed inside the operation unit main body 11 is elastically pushed by the lock spring 16, and the distal end of the lock pin 15 protrudes toward the inner side of the lock holder 17, as depicted in FIG. 4.

(22) The assembly of the pushbutton 12, the push rod 13, and the return spring 14 is inserted from above into the operation unit main body 11. In this case, the lock pin 15 which is pressed inward by the lock spring 16 on the main body 11 side pushes the push rod 13 such as to ride over the receding-protruding section on the outer circumference of the push rod 13 and be locked in a first recess 13a for locking. Then, a trigger spring 18 and a push body 19 are inserted from below into the operation unit main body 11, an engagement hole 19a in the push body 19 is engaged with an engagement protrusion 13f at the lower end side of the push rod 13, the main body 11 and the pushbutton 12 are integrally joined, and the operation unit 10 is formed.

(23) The operation unit main body 11 and the pushbutton 12 are joined to be capable of moving in the axial direction and rotation direction with respect to each other. However, since two rotation suppressing protrusions 11j are provided with a spacing of angle C on the inner side of the upper portion of the operation unit main body 11, and a rotation suppressing protrusion 12d corresponding thereto and located on the pushbutton 12 is fitted between the two protrusions 11j, the range of rotation of the pushbutton 12 relative to the operation unit main body 11 is restricted to the range of angle C. Further, when the push rod 13 is inserted into the operation unit main body 11, a rotation preventing protrusion 11k provided inside the operation unit main body 11 correspondingly to a rotation preventing groove 13g provided in the axial direction on the outer circumference of the push rod 13 engages with the rotation preventing groove 13g, thereby preventing the push rod 13 from rotating relative to the operation unit main body 11 and allowing only the vertical (axial) movement.

(24) The engagement of the engagement protrusion 12c of the pushbutton 12 with the L-shaped engagement groove 13d of the push rod 13 allows the pushbutton 12 to be rotated within a range of a rotation angle D (see FIG. 4) relative to the push rod 13, but in a range of angle C in which the rotation relative the operation unit main body 11 can be performed, the pushbutton 12 is stopped by the L-shaped engagement groove 13d of the push rod 13.

(25) In the operation unit 10 having such a structure, in a standby state before the pushbutton 12 is pushed, the return spring 14 pushes up the pushbutton 12, and the lock pin 15 is engaged with the first recess 13a provided on the outer circumference of the intermediate portion of the push rod 13, thereby locking the push rod 13 in this position. Therefore, the pushbutton 12 is held, this position serving as a standby position. The lock pin 15 is supported by the lock holder 17 through the lock spring 16 to be radially retractable inside the operation unit main body 11.

(26) When the pushbutton 12 is pushed axially by a predetermined force or a stronger force, the push rod 13 receives this force and the inclined upper wall of the recess 13a pushes the lock pin 15 in the outer circumferential direction against the lock spring 16, thereby releasing the engagement of the recess 13a and the lock pin 15, and pushing the push rod 13 over the lock pin 15. The lock pin 15 that came out of the recess 13a engages with a second recess 13b in the upper portion of the recess 13a and holds the pushbutton 12 and the push rod 13 in the pushing operation position thereof.

(27) The push rod 13 is arranged to push down the push body 19, which is linked to a movable contactor holder 22 of the switch unit through the trigger spring 18, by such a pushing operation. The lower end of the push body 19 hits the upper end of the movable contactor holder 22 of the switch unit 20, pushes the movable contactor holder down, and opens/closes the opening-closing contact mechanism of the switch unit 20 (see FIG. 1).

(28) Further, a fixing thread 11d is provided on the outer circumference of the body portion 11c below a flange portion 11b of the operation unit main body 11. A fastening nut 11e is screwed onto the thread 11d to fasten and fix the operation unit 10 to a panel such as a control panel. An axial engagement groove 11f (see FIG. 6) for connecting and engaging the operation unit 10 and the switch unit 20 is provided on the outer circumference on the lower end side of the body portion 11c of the operation unit main body 11. As shown in detail in FIGS. 9(a)-9(d), the engagement groove 11f is provided with an axial inclined portion 11f-1 which rises obliquely from a lower end to the upper left side, a horizontal portion 11f-2 which is connected at the upper end of the inclined portion 11f-1 and extends in the horizontal direction, and a vertical portion 11f-3 that is connected at the right end of the horizontal portion 11f-2 and extends slightly upward in the vertical direction.

(29) An engagement groove 11g for engagement with an engagement ridge 21b extending axially at the inner circumference of a cylindrical portion 21a of a switch unit main body 21 of the switch unit 20 is additionally provided at the outer circumference of the lower body portion 11c of the operation unit main body 11 (see FIG. 6).

(30) The switch unit 20 that is detachably connected to such an operation unit 10 is explained below.

(31) As depicted in FIGS. 1 and 6, the switch unit 20 is provided with the rectangular box-shaped switch unit main body 21. The main body 21 is provided with at least one pair of fixed contacts 25-1a, 25-2b integrally connected to each pair of output terminals 25a, 25b that is fixedly disposed at the lower end side of the main body. The references with the letter (a) attached thereto represent normally open contacts which are usually open, that are, the contacts constituting the so-called (a) contacts, and the references with the letter (b) attached thereto represent normally closed contacts which are usually closed, that are, the contacts constituting the so-called (b) contacts.

(32) Further, as shown in detail in FIG. 6, the movable contactor holder 22 that holds movable contactors 26a, 26b in the form of bridging pieces provided with a pair of movable contacts 26-1a, 26-2b at the two ends is accommodated movably in the vertical direction inside the main body 21 through a contact spring 27 imparting an urging force to the contacts. The normally open movable contact 26-1a and the normally closed movable contact 26-2b held by the movable contactor holder 22 are disposed facing the normally open fixed contact 25-1a and the normally closed fixed contact 25-2b, and form the opening-closing contact mechanism. In this case, the contact spring 27 is formed from a compressive coil spring and generates an urging force in the direction pushing the movable contactor holder 22 upward. As a result, when the pushbutton 12 is in the usual standby state (state in which the pushbutton 12 is not pushed), as depicted in FIG. 1, the normally open movable contact 26-1a which is held by the movable contactor holder 22 is placed in a state of separation from the fixed contact 25-1a, and the normally closed movable contact 26-2b is placed in a state of contacting the fixed contact 25-2b. This is the opening-closing state of the opening-closing mechanism at the time the operation unit is in the standby state.

(33) Further, as depicted in FIGS. 6 and 7, the cylindrical portion 21a having cut-out portions 21c in parts thereof, the cut-out portions 21c facing each other, is formed protruding at the upper portion of the switch unit main body 21 in order to join a rotary drive portion 30.

(34) The rotary drive portion 30 is provided with a rotary cover 31, a rotary drive plate 32, and a rotary drive spring 33. Engagement protrusions 32b formed at the inner circumferential side of the rotary drive plate 32, which is formed to be split in two substantially semicylindrical portions, are inserted in and engaged with a pair of semicircular-arc grooves 21d formed at the outer circumference of the cylindrical portion 21a of the switch unit main body 21, thereby rotatably supporting the rotary drive plate 32 with the cylindrical portion 21a. A cam piece 32a having a cam surface inclined in the circumferential direction is partially formed at the lower end of the rotary drive plate 32. As shown in FIG. 8, the cam piece 32a has at the lower end thereof an inclined cam surface which connects together a position with a larger height Hh and a position with a smaller height Hl from the upper end of the rotary drive plate 32. The cam piece 32a penetrates into the main body through a through hole 21e (see FIG. 7) in the upper wall of the switch unit main body 21, and the cam surface is joined to the upper surface of a pressure-receiving piece 22b that is formed in a protruding condition on the outer circumferential side of the movable contactor holder 22 that holds the movable contacts 26-1a, 26-2b (see FIGS. 1 and 6).

(35) The rotary drive plate 32 supported by the cylindrical portion 21a of the switch unit main body 21 is covered from above with the rotary cover 31. The rotary drive spring 33 formed from a twisted coil spring is inserted between the rotary cover 31 and the rotary drive plate 32, and the two ends of the rotary coil spring are engaged. For this purpose, a round fitting hole 31a that fits the cylindrical portion 21a of the switch unit main body 21 is provided in the central portion of the rotary cover 31, and a fitting hole 31b that fits the upper protrusion 32d of the rotary drive plate 32 is provided outside the round fitting hole 31a. Further, a protrusion 31c engaging with the engagement groove 11f provided in the lower body portion 11c of the operation unit main body 11 is formed protruding at a position facing the inner circumference of the fitting hole 31a.

(36) When the rotary cover 31 is covered on the rotary drive plate 32, the distal end portion of the cylindrical portion 21a of the switch unit main body 21 is loosely fitted to the fitting hole 31a of the rotary cover 31, and the rotary cover 31 is rotatably supported on the switch unit main body 21. Further, at this time, the protrusion 32d at the upper portion of the rotary drive plate 32 is fitted to the fitting hole 31b of the rotary cover 31, and the rotary cover 31 and the rotary drive plate 32 are joined integrally together. Therefore, the rotary cover 31 and the rotary drive plate 32 are integrally rotatably supported by the cylindrical portion 21a of the switch unit main body 21. The rotary drive spring 33 mounted between the rotary cover 31 and the cylindrical portion 21a of the switch unit main body 21 is locked at one end to the cylindrical portion 21a and locked at the other end to the rotary cover 31, whereby elastic restoration forces are applied in the axial and rotation directions to the rotary cover 31 and the rotary drive plate 32.

(37) When the operation unit 10 and the switch unit 20 arranged in the above-described manner are separated from each other, as depicted in FIG. 10(a), the rotary drive portion 30 located on the switch unit main body 21 is rotated rightward, as shown by an arrow R, by the restoration force of the rotary drive spring 33 and placed at a standby position which is slightly shifted from the position of alignment with the switch unit main body 21. As a result, the rotary drive plate 32 located inside the rotary drive portion 30 is also placed at a standby position, and the cam piece 32a formed in a protruding state at the lower end of the rotary drive plate is joined to the pressure-receiving piece 22b of the movable contactor holder 22 at a position with the larger height Hh (see FIGS. 7 and 8). As a consequence, the movable contactor holder 22 is pushed deeply downward according to the height Hh of the cam piece 32a against the urging force of the contact spring 27. Therefore, in the opening-closing contact portion of an (a) contact arrangement, the normally open movable contact 26-1a contacts the normally open fixed contact 25-1a and becomes a switch-on state. In the opening-closing contact portion of a (b) contact arrangement, the normally open movable contact 26-2b separates from the normally open fixed contact 25-2b, and becomes a switch-off state. Such an opening-closing state of the opening-closing contact portion is the same as the opening-closing state at the time of the standby state of the operation unit in a state in which the operation unit 10 is joined to the switch unit 20.

(38) The procedure by which the operation unit 10 is thus joined to the switch unit 20, in which the rotary drive portion 30 is placed at the standby position, to obtain the usage state will be explained hereinbelow with reference to FIGS. 9(a)-9(d).

(39) The lower body portion 11c of the main body 11 of the operation unit 10 is inserted from above into the cylindrical portion 21a of the switch unit 20 in which the rotary drive portion 30 is placed at the standby position. For this purpose, initially, as depicted in FIG. 9(a), the protrusion 31c of the rotary cover 31, which protrudes inward of the cylindrical portion 21a of the switch unit main body 21, and the second protrusion 32c of the rotary drive plate 32 are fitted into the engagement groove 11f on the outer circumference of the lower body portion 11c of the operation unit main body 11. Then, the operation unit 10 and the switch unit 20 are aligned such that the ridge 21b provided at the cylindrical portion 21a of the main body 21 of the switch unit 20 is inserted into the engagement groove 11g of the operation unit main body 11.

(40) Once such an alignment is attained, the lower body portion 11c of the operation unit main body 11 is inserted from above into the cylindrical portion 21a of the switch unit 20, in which the rotary drive portion 30 is placed at the standby position, and pushed down while the protrusions 31c, 32c are fitted to the engagement groove 11f, and the engagement ridge 21b is fitted to the engagement groove 11g (FIG. 9(b)). As the operation unit 10 is pushed, the protrusion 31c of the rotary cover 31 and the protrusion 32c of the rotary plate 32, which are fitted with the engagement groove 11f, are pushed by the inner wall of the inclined portion 11f-1 of the engagement groove 11f and moved leftward, as shown by an arrow L. Therefore, the rotary cover 31 and the rotary plate 32 are rotated to the left while twisting the rotary drive spring 33.

(41) When the protrusion 31c of the rotary cover 31 and the protrusion 32c of the rotary plate 32 reach the horizontal portion 11f-2 of the engagement groove 11f, as shown in FIG. 9(c), the protrusions are rotated rightward, as shown by the arrow R, by the restoration force of the rotary drive spring 33 twisted by the rotation of the rotary cover 31 and the rotary plate 32. As a result, the protrusions 31c and 32c move to the right end of the horizontal portion 11f-2 of the engagement groove 11f. Further, since the rotary cover 31 is also driven upward by the axial restoration force of the rotary return spring 33, the rotary cover 31 rises and only the protrusion 31c of the rotary cover 31 moves into the vertical portion 11f-3 of the engagement groove 11f, as depicted in FIG. 9(d). As a result, the protrusion 31c of the rotary cover 31 is locked to the vertical portion 11f-3 of the engagement groove 11f of the operation unit 11. Therefore, the rotary drive portion 30 is fixed and cannot rotate with respect to the body portion 11a of the operation unit main body 10.

(42) The operation unit 10 is thus inserted to the very end into the rotary drive portion 30, and becomes the usable state when the operation unit 10 is joined to the switch unit 20, as shown in FIG. 10(b). In this state, the rotary drive portion 30 is fixed in alignment with the usage position of the main body 21 of the switch unit 20. When the rotary drive portion 30 is placed at this position, the rotary plate 32 located inside thereof rotates leftward, as shown by the arrow L, together with the rotary drive portion 30. Therefore, the joining position of the rotary drive plate 32 and the pressure-receiving piece 22b of the movable contactor holder 22 of the switch unit 20 becomes a low position with the height Hl of the cam piece 32a, and the movable contactor holder 22 is pushed up to the position with the height Hl of the cam piece 32a by the contact spring 27. As a result, the normally open movable contact 26-1a held by the movable contactor holder 22 separates from the normally open fixed contact 25-1a, the normally closed movable contact 26-2b and the normally closed fixed contact 25-2b are closed, and the opening-closing contact portion becomes an opening-closing state at the time of the standby state.

(43) When the switch unit 20 and the operation unit 10 are separated from each other from the joined state thereof, the operations may be performed according to a procedure reversed with respect to the joining procedure illustrated by FIG. 9(a)-9(d). However, unless the rotary cover 31 is pushed down to a position at which the protrusion 31c overlaps the protrusion 32c of the rotary drive plate 32 in the state shown in FIG. 9(d), the rotary cover 31 cannot be rotated, therefore, it is necessary to perform the operation of pushing down the rotary cover 31.

(44) In the switch device 1 depicted in FIG. 1, the operation unit 10 is thus joined to the switch unit 20 and placed in the standby state. In this state, the rotary drive plate 32 of the rotary drive portion 30 pushes the pressure-receiving piece 22a of the movable contactor holder 22 of the switch unit 20 at a position with a small height Hl of the cam piece 32a. Therefore, the rotary drive plate 32 is in a standby position at which the movable contactor holder 22 is pushed up. As a result, the normally open movable contact 26-1a and the normally open fixed contact 25-1a are separated from each other and become the switch-off state, and the normally closed movable contact 26-2b and the normally closed fixed contact 25-2b are closed and become the switch-on state.

(45) When the pushbutton 12 of the operation unit 10 is pushed in the direction of an arrow P, as depicted in FIG. 11, the push rod 13 is pushed down in response thereto. Therefore, the lock pin 15 rides over a step 13c located between the two recesses of the push rod 13 joined to the pushbutton 12, engages with the upper recess 13b, and holds the pushbutton 12 at the pushing operation position. In response to the downward pushing of the push rod 13, the push body 19 is pushed down through the trigger spring 18. As a result, the upper end of the movable contactor holder 22 of the switch unit 20 abutting against the push body 19 is pushed down against the urging force of the contact spring 27. Therefore, the normally open movable contact 26-1a and the normally open fixed contact 25-1a are closed and become the switch-on state, and the normally closed movable contact 26-2b and the normally closed fixed contact 25-2b are separated from each other and become the switch-off state. This is the opening-closing state of the opening-closing contact mechanism at the time the operation unit 10 is in the pushing operation state.

(46) In order to return the switch device 1 in such an operation state to the standby state such as depicted in FIG. 1, the pushbutton 12 is turned in the direction of the arrow displayed on the surface of the pushbutton 12 and the locked state caused by the lock pin 15 is released.

(47) In order to facilitate such an operation of releasing the locked state, as shown in FIG. 5, cam portions 11m and 12e having inclined surfaces that rise from right to left along the circumference are provided facing each other on the inner circumference of the operation unit main body 11 of the operation unit 10 and the outer circumference of the inner wall of the pushbutton 12 facing thereto.

(48) In the standby state before the pushing operation of the pushbutton 12, the lock pin 15 is engaged with the recess 13a in the lower part of the push rod 13 joined to the pushbutton 12, as depicted in FIG. 5(a), and the locked state is maintained. Therefore, the pushbutton 1 is at the push-up position, and the cam portion 11m of the operation unit main body 11 is separated from the cam portion 12e of the pushbutton 12.

(49) In the operation state in which the pushbutton 12 has been pushed, the lock pin 15 engages with the recess in the upper part of the push rod 13 and the locked state is maintained. Therefore, the pushbutton 12 is at the push-down position, the cam portion 12e of the pushbutton 12 approaches the cam portion 11m of the operation unit main body 11, and practically no gap is present therebetween.

(50) When the pushbutton 12 is rotated from this state to the right in the preset range of rotation angle C described hereinabove, the cam surface of the cam portion 12e of the pushbutton 12 comes into contact with the cam surface of the cam portion 11m of the operation unit main body 11 and is pushed up along this cam surface. The push rod 13 rises accordingly, and the recess 13a located in the lower part thereof engages with the lock pin 15 and returns to the original standby position.

(51) When the locked state at the operation position created by the lock pin 15 is thus released, the movable contactor holder 22, the push rod 13, and the pushbutton 12 are pushed by the restoration forces of the contact spring 27 and the trigger spring 18, and returned to the position of the standby state. The pushbutton 12 is returned to the original rotation position by the twisted return spring 14 and becomes the standby state depicted in FIG. 1.

(52) If by any chance an accident occurs such that the switch unit 20 of the switch device 1 separates from the operation unit 10, as depicted in FIG. 10(a), since the operation unit 10 and the rotary drive portion 30 are not joined together anymore, the rotary drive portion 30 is rotated to the right, as shown by the arrow R, by the restoration force of the internal rotary return spring 33 and returns to the standby position depicted in FIG. 10(a). At the same time, the rotary drive plate 32 located inside the rotary drive portion 30 is also rotated. Therefore, the cam piece 32a applies pressure to the pressure-receiving piece 22a of the movable contactor holder 22 at a position with a large height Hh of the cam piece 32a. As a result, the movable contactor holder 22 is pushed downward. Therefore, the normally closed movable contact 26-2b and the normally closed fixed contact 25-2b are separated from each other and become the switch-off state, the normally open movable contact 26-1a and the normally open fixed contact 25-1a are closed and become a switch-on state, and the opening-closing contact mechanism becomes the state same as the opening-closing state at the time the operation unit is in the operation state. Therefore, the switch device can be used as an emergency safety switch.

(53) In the switch device 1 of the invention, in a state in which the rotary drive portion 30 is placed at the usage position and the pushbutton 12 is in the standby state, as depicted in FIG. 1, the movable contacts of the opening-closing contact portion of the switch unit 20 are urged by the contact spring 27 in the direction of separating the opening-closing portion of the (a) contact and in the direction of closing the opening-closing portion of the (b) contact. Therefore, even when an impact force is applied to the switch device in this state, an erroneous operation such that closes the opening-closing portion of the (a) contact and separates the opening-closing portion of the (b) contact cannot occur. As a result, the operation reliability can be increased.

EXPLANATION OF REFERENCE NUMERALS

(54) 1switch device, 10operation unit, 11operation unit main body, 12pushbutton, 13push rod, 20switch unit, 21switch unit main body, 22movable contactor holder, 25-1anormally open fixed contact; 25-2bnormally closed fixed contact, 26-1anormally open movable contact, 26-2bnormally closed movable contact, 27contact spring, 30rotary drive portion, 31rotary cover, 32rotary drive plate, 32acam piece, 33rotary return spring