CN101620944B - Button switch - Google Patents

Abstract

The present invention provides a kind of button switch, which is difficult to generate a partial difference when switching between conducting states of multiple fixed contacts. The button switch includes an operating member 2 arranged in a housing 1 movably up and down and operating by pressing a press part 21, a movable contact piece 3 with movable contact parts 3a, 3b and arranged on the operating member 2 in the housing 1, a wound spring 4 for recovering and located below the press part 21, and a plurality of fixed contacts 6-8 arranged in the housing 1, wherein the public fixed contact 6 is located in a hollow part 4a of the wound spring in a standing mode, such that a first movable contact part 3a of the movable contact piece 3 always contact to the public fixed contact 6 slidingly. Furthermore, on an external side of the hollow part 4a, switching fixed contacts (NO fixed contact 7 and NC fixed contact 8) are arranged nearby the wound spring 4, such that a second movable contact part 3b of the movable contact piece 3 contacts with the two fixed contacts 7, 8 with separation and contact slidingly.

Description

Push-button switch

Technical Field

The present invention relates to a push switch in which a movable contact member that is in slidable contact with a plurality of fixed contacts is held by an operating member, and the operating member is press-fitted to switch the conductive state between the plurality of fixed contacts.

Background

In this push switch, a plurality of movable contact portions are provided on a movable contact member that is held by an operating member and moves back and forth integrally, and when the operating member is pushed in against the urging force of a return elastic member, the movable contact portions are configured to slide with respect to a common fixed contact that is a first fixed contact and a switching fixed contact that is a second fixed contact arranged in a housing. The switching fixed contact is composed of, for example, an NO (normally open) fixed contact and an NC (normally closed) fixed contact, and when the operation member is not operated, a predetermined movable contact portion is brought into sliding contact with the NC fixed contact, and when the operation member is press-fitted with a predetermined stroke, the movable contact portion is separated from the NC fixed contact and brought into sliding contact with the NO fixed contact. The other movable contact portion that is in electrical conduction with the movable contact portion is always in sliding contact with the common fixed contact. Therefore, when the operation member is pushed in, a predetermined movable contact portion is brought into contact with and separated from the switching fixed contact, thereby switching the ON/OFF contacts.

Conventionally, as such a push switch, there is known a push switch in which three fixed contacts and a return coil spring are arranged in a row in a lateral direction in a housing, and a pressing portion of an operating member is projected from directly above the coil spring to above the housing (for example, see patent document 1). In the related conventional example, the operation member is provided with an extension portion extending in the lateral direction in the housing, and the first to third movable contact portions are formed at three positions of the laterally long movable contact member attached to the extension portion. Wherein the first movable contact portion is located in the vicinity of the coil spring, the third movable contact portion is located at the farthest position from the coil spring, and the second movable contact portion is located in the middle of the first movable contact portion and the third movable contact portion. Further, as the three fixed contacts, a common fixed contact that always makes sliding contact with the first movable contact portion, an NO fixed contact that makes sliding contact with the second movable contact portion at the time of press-in operation, and an NC fixed contact that makes sliding contact with the third movable contact portion at the time of non-operation stand in the housing. The three fixed contacts are led out from a connection terminal group provided on the bottom surface of the housing, and the connection terminal group is connected to an external circuit.

In the conventional push-button switch having such a simple configuration, the NC fixed contact and the common fixed contact are brought into conduction via the movable contact member when the operating member is not operated, but when the pressing portion of the operating member is pressed via the actuator pressure, the movable contact member and the operating member are lowered integrally in the case, so that the third movable contact portion is separated from the NC fixed contact, and the second movable contact portion is brought into sliding contact with the NO fixed contact. As a result, the conduction between the NC fixed contact and the common fixed contact is released, and the NO fixed contact and the common fixed contact are in a conductive state, so that the contact switching from OFF to ON is performed. Further, when the relevant press-in operation is performed, the coil spring is compressed directly below the pressing portion of the operating member, and therefore, when the press-in operating force to the pressing portion is removed, the operating member is pressed up to the original position (non-operating position) by the elastic restoring force of the coil spring. As a result, the second movable contact portion is separated from the NO fixed contact, and the third movable contact portion automatically returns to the original state of sliding contact with the NC fixed contact.

Patent document 1: japanese patent laid-open publication No. 2006 and 255154

However, in the conventional push-button switch, the common fixed contact and the switching fixed contact (NO fixed contact and NC fixed contact) are arranged in parallel on the outer side of the return coil spring located directly below the pressing portion of the operating member, and the return coil spring and the switching fixed contact are arranged at positions far apart from each other. That is, the operation member needs to have a slight play and be supported in the housing so as to be capable of reciprocating, and when the operation member is press-fitted, the operation member is easily inclined by an amount corresponding to the backlash (ガタ) in the play, and therefore, there are problems as follows: the slight inclination of the operating member causes variation in the operation timing of contact switching, which leads to a reduction in the ON or OFF accuracy.

Disclosure of Invention

The present invention has been made in view of the above-described circumstances of the prior art, and an object of the present invention is to provide a push switch in which variation in timing of switching operation of conduction states between a plurality of fixed contacts is less likely to occur.

In order to achieve the above object, a push switch according to the present invention includes an operating member having a pressing portion to be press-fitted, a case holding the operating member so as to be capable of reciprocating, a movable contact member held by the operating member and reciprocating in the case, a return elastic member disposed in the case on a side extending in a press-fitting operation direction of the pressing portion and pushing back the operating member to a non-operating position, and a first fixed contact and a second fixed contact provided in the case, the movable contact member having a first movable contact portion in sliding contact with the first fixed contact and a second movable contact portion in sliding contact with the second fixed contact, and a conductive state between the first fixed contact and the second fixed contact being switched by the first movable contact portion and the second movable contact portion in accordance with the press-fitting operation of the pressing portion, wherein the return elastic member has a hollow portion, and the first fixed contact is raised in the hollow portion along a press-in operation direction of the pressing portion.

In the push switch configured as above, since the first fixed contact standing along the push-in operation direction of the pressing portion is disposed in the hollow portion of the restoring elastic member, it is not necessary to make the second fixed contact disposed outside the hollow portion far away from the restoring elastic member. That is, since it is not necessary to largely extend the movable contact member toward the restoring elastic member, even if the operating member is inclined at the time of press-fitting operation, the contact position of the movable contact portion with respect to the fixed contact is not likely to be deviated, and the switching position accuracy of the conduction state between the first fixed contact and the second fixed contact, that is, the so-called ON or OFF accuracy is improved. Further, it is preferable that the coil spring is a restoring elastic member having a hollow portion.

In the above configuration, when the first fixed contact is a common fixed contact which is in sliding contact with the first movable contact portion at all times, the second fixed contact is a switching fixed contact which is in sliding contact with and separated from the second movable contact portion, and the common fixed contact is disposed in the hollow portion, a metal coil spring is used as the elastic member for recovery, and even if the coil spring is in contact with the common fixed contact in the hollow portion due to an impact or the like, the common fixed contact and the first movable contact portion are always in conduction, and therefore, it is difficult to exert an adverse influence on the output of the electric signal.

In the above configuration, the first switching fixed contact and the second switching fixed contact are arranged at positions separated from each other along the direction of pushing operation of the pushing portion, and both the first switching fixed contact and the second switching fixed contact, which are formed of the NO fixed contact and the NC fixed contact, can be arranged in the vicinity of the return elastic member, for example, so that ON or OFF accuracy as contact switching position accuracy can be greatly improved.

In the above configuration, the movable contact member has a holding portion held by the operating member, the first movable contact portion and the second movable contact portion are coupled to the holding portion, the first movable contact portion and the second movable contact portion are arranged in a dispersed manner inside and outside the hollow portion of the elastic member for restoration, and the holding portion located between the first movable contact portion and the second movable contact portion is biased toward the operating member side from one end portion of the elastic member for restoration.

In the above configuration, the first movable contact portion is formed in a shape sandwiching the first fixed contact, and the second movable contact portion is formed in a shape sandwiching the second fixed contact, and in this case, since the contact between each movable contact portion and the corresponding fixed contact is stable, the reliability is high. In this case, if the movable contact member is formed of a metal plate, the holding portion is formed of a plate-like shape, a pair of U-shaped elastic pieces having substantially U-shapes are connected to both sides of the holding portion so that plate surfaces thereof face each other at a predetermined interval, and portions bent in directions approaching each other at distal ends of the U-shaped elastic pieces form the movable contact portions sandwiching the corresponding fixed contacts, the movable contact member operates within an elastic range by the U-shaped elastic pieces, and therefore, the contact with the fixed contacts is further stabilized. In this case, if the first movable contact portion is disposed in the hollow portion of the resilient member for return so that the open sides of the pair of U-shaped resilient pieces face the operating member side, the movable contact member can be easily obtained which can reliably hold the first fixed contact in the hollow portion while avoiding interference with the resilient member for return. In this case, if the other end portion of the resilient member for restoration is held by the mounting portion provided in the housing and the first fixed contact located in the hollow portion is raised from a position shifted from the center of the mounting portion in a direction away from the second fixed contact located outside the hollow portion, a desired space can be easily secured between the resilient member for restoration and the U-shaped resilient piece in the hollow portion, and therefore the U-shaped resilient piece that does not interfere with the resilient member for restoration can be easily formed.

In the push-button switch of the present invention, the first fixed contact standing along the press-in operation direction of the press portion is disposed in the hollow portion of the elastic member for restoration formed of a coil spring or the like, and the second fixed contact can be disposed in the vicinity of the elastic member for restoration on the outside of the hollow portion, so that the contact position of the movable contact portion with respect to the fixed contact portion is less likely to be displaced even if the operation member is tilted at the time of press-in operation. Therefore, even if the operating member is inclined, the timing of the switching operation of the ON state of the push switch between the first fixed contact and the second fixed contact is less likely to vary, and the accuracy of the switching position of ON or OFF can be improved.

Drawings

Fig. 1 is a front view of a push button switch according to an embodiment of the present invention.

Fig. 2 is a sectional view showing a non-operation state of the push switch.

Fig. 3 is an explanatory diagram of an internal configuration corresponding to fig. 2.

Fig. 4 is a sectional view showing a press-in operation state of the push switch.

Fig. 5 is a main part explanatory diagram corresponding to fig. 4, showing a contact state of the movable contact member and the switching fixed contact.

Fig. 6 is a perspective view of a movable contact member used in the push button switch.

Description of the figures

1 casing

2 operating part

3 Movable contact sheet (Movable contact component)

3a first movable contact part

3b second movable contact part

31 holding part (Flat plate part)

4 coil spring (elastic component for recovery)

4a hollow part

5a common terminal

5b, 5c switching terminal

6 common fixed contact (first fixed contact)

7NO fixed contact (switching fixed contact: second fixed contact)

8NC fixed contact (switching fixed contact: second fixed contact)

11 upper shell

12 lower shell

12a spring mounting part (mounting part)

21 pressing part (pressing shaft part)

32. 33U-shaped elastic sheet

Detailed Description

An embodiment of the present invention is explained with reference to the drawings, fig. 1 is a front view of a push button switch according to an embodiment of the present invention, fig. 2 is a sectional view showing a non-operation state of the push button switch, fig. 3 is an explanatory view of an internal structure corresponding to fig. 2, fig. 4 is a sectional view showing a press-in operation state of the push button switch, fig. 5 is an explanatory view of a main portion in a direction orthogonal to fig. 4 showing a contact state of a movable contact member and a switching fixed contact, and fig. 6 is a perspective view of the movable contact member used in the push button switch. In fig. 2 to 5, for the sake of easy understanding, the fixed contacts are indicated by dot regions.

The push-button switch shown in these figures mainly comprises a case 1 having a rectangular box shape (a horizontally long rectangular parallelepiped shape) in plan view, which is formed by combining an upper case 11 and alower case 12, an operatingmember 2 having apressing portion 21 and held in the case 1 movably in the up-down direction, amovable contact piece 3 as a movable contact member fixed to the operatingmember 2 and having first and secondmovable contact portions 3a and 3b, acoil spring 4 as an elastic member for recovery disposed below thepressing portion 21 in the case 1, threeconnection terminals 5a to 5c provided vertically on the bottom surface of thelower case 12, and a common fixedcontact 6 as a first fixed contact and switching fixed contacts (NOfixed contact 7 and NC fixed contact 8) as second fixed contacts led out from therespective connection terminals 5a to 5c into the housing 1.

Anopening 11a is formed in a rectangular upper surface portion of the upper case 11, and a pressing portion (pressing shaft portion) 21 of the operatingmember 2 protrudes upward from the opening 11 a. A dust cover 9 made of a highly flexible elastic material such as rubber is fixed around the opening 11 a. The dust cover 9 is fitted to thepressing portion 21 so as to cover theopening 11a, and functions as a dust-proof cover, and the dust cover 9 is easily elastically deformed in accordance with the vertical movement of thepressing portion 21, so that the operation of theoperation member 2 is not adversely affected. In fig. 4, the dust cover 9 is not shown.

Thelower case 12 is rectangular in plan view, and is formed by embedding a conductive metal plate as a material of theconnection terminals 5a to 5c and the fixedcontacts 6 to 8. The threeconnection terminals 5a to 5c having a columnar shape are constituted by acommon terminal 5a vertically provided on one side portion of thelower case 12, a switching terminal 5b vertically provided on a central portion of thelower case 12, and a switching terminal 5c vertically provided on the other side portion of thelower case 12. Thecommon terminal 5a leads out a common fixedcontact 6 into the housing 1, one switchingterminal 5b leads out an NO (normally open) fixedcontact 7 into the housing 1, and the other switching terminal 5c leads out an NC (normally closed) fixedcontact 8 into the housing 1. Aspring mounting portion 12a is projected from the upper surface side of one side portion of thehousing 12, and the lower end portion of thecoil spring 4 is mounted to the outer peripheral portion of thespring mounting portion 12a, whereby the inner peripheral portion thereof is positioned.

A common fixedcontact 6 having a substantially quadrangular prism shape stands in thehollow portion 4a of thedisc spring 4. The common fixedcontact 6 is provided upright at a position (offset position) outside the center of thespring mounting portion 12a of thelower case 12, specifically, at a position offset in a direction (rightward in fig. 2) away from the NO fixedcontact 7 or the NC fixedcontact 8 located outside thehollow portion 4 a. Both the NO fixedcontact 7 and the NC fixedcontact 8 are disposed outside thehollow portion 4a and in the vicinity of thecoil spring 4, and the NC fixedcontact 8 is disposed in a horizontal posture with a predetermined interval above the NO fixedcontact 7 provided upright on thelower case 12. That is, the common fixedcontact 6, the NO fixedcontact 7, and the NC fixedcontact 8 are arranged to be located on the same plane. As shown in fig. 5, which shows a direction perpendicular to fig. 4, NOfixed contact 7 and NC fixedcontact 8 include a gap portion, and their outer surfaces and inner surfaces are flush with each other. The gap portion is formed by providing an insulating resin material constituting thelower case 12 between the NO fixedcontact 7 and the NC fixedcontact 8.

The operatingmember 2 is formed of synthetic resin, and includes abase portion 22 for holding themovable contact piece 3 and acolumnar pressing portion 21 provided to protrude from thebase portion 22 in the housing 1. Theoperation member 2 is held movably in the up-down direction shown in fig. 2 by abase portion 22 that is substantially rectangular as viewed along the inner wall guide plane of the housing 1 (upper housing 11). Further, thepressing portion 21 guides its up and down movement through theopening 11a of the upper case 11. A holdingportion 31 of themovable contact piece 3 described below, which is biased by the upper end portion of thecoil spring 4, is abutted on the flat top surface of thebase portion 22. That is, thecoil spring 4 is inserted in a compressed state between thebase portion 22 and thespring attachment portion 12a on the lower side, and therefore the operatingmember 2 is elastically biased upward by thecoil spring 4. Further, when pressingportion 21 is pushed and moved downward,operation member 2 is configured not to interfere with common fixedcontact 6, NOfixed contact 7, and NC fixedcontact 8. That is, a concave cutout (not shown) capable of receiving the distal end portion of the common fixedcontact 6 is provided at the lower portion of thebase portion 22 and thepressing portion 21 at a position facing the upper end portion of the common fixedcontact 6. Further, a slit penetrating in the vertical direction is provided at the side end portion of thebase portion 22 on the NO fixedcontact 7 and NC fixedcontact 8 side (left side in fig. 2), and thebase portion 22 is configured not to abut against the NO fixedcontact 7 and NC fixedcontact 8. Fig. 2 and 4 are cross-sectional views taken not at the center of each of the fixedcontacts 6 to 8 but at positions in a state where the firstmovable contact portion 3a and the common fixedcontact 6 are in contact with each other as described below. The pushingportion 21 protrudes upward of the housing 1 through theopening 11a, and the tip end portion of the pushingportion 21 is pushed in by an actuator not shown.

Themovable contact piece 3 is a conductive metal plate formed in the shape shown in fig. 6. Themovable contact piece 3 is configured with a flat plate-like holding portion 31 at the center thereof, which is fixed to the operatingmember 2 by caulking or the like. A pair of U-shapedelastic pieces 32 facing each other in a substantially U-shape in front view are formed at one end ofmovable contact piece 3, and a pair of U-shapedelastic pieces 33 facing each other are similarly formed at the other end ofmovable contact piece 3. That is, a pair of U-shapedelastic pieces 32 and 33 facing each other are integrally formed on both sides of the holdingportion 31. As shown in fig. 6, the holdingportion 31 has a protrudingportion 31a that protrudes outward at a distance greater than the opposing distance between the pair of U-shapedelastic pieces 32 and 33. Then, a pair of projections (not shown) provided on thebase portion 22 of theoperation member 2 are crushed and deformed so as to sandwich the two projectingportions 31a in the width direction as the projecting direction of the projectingportions 31a, and the holdingportion 31 is fixed to thebase portion 22 by caulking or the like. Thereby, themovable contact piece 3 is held by theoperation member 2. The holdingportion 31 is formed of a flat plate portion. Since the upper end portion of thecoil spring 4 abuts on the holdingportion 31, themovable contact piece 3 is biased toward the operatingmember 2 by the elastic force of thecoil spring 4. This prevents themovable contact piece 3 from rattling even if themovable contact piece 3 is not sufficiently fixed to the operatingmember 2. The holdingportion 31 has connectingportions 31b projecting outward in a direction intersecting the extending direction of the projectingportion 31a, and the pair of U-shapedelastic pieces 32 and 33 are connected to the holdingportion 31 by the two connectingportions 31 b. That is, a pair of U-shapedelastic pieces 32 and 33 are formed by bending metal plates whose plate surfaces face each other with a predetermined interval from theconnection portion 31 b. The pair of U-shapedelastic pieces 32 and the pair of U-shapedelastic pieces 33 are formed in a symmetrical shape (plane symmetry) with the center of the holdingportion 31 as a symmetrical plane (a plane in the direction in which the protrudingportion 31a is provided).

Here, the pair of U-shapedelastic pieces 32 and 33 having symmetrical shapes will be described in detail based on the state in which themovable contact piece 3 is assembled as shown in fig. 2 to 4. Further, since the shape is symmetrical, only one pair of U-shapedelastic pieces 32 will be described. The U-shapedelastic piece 32 includes: firstextended portion 32a extended by a predetermined distance fromcoupling portion 31b toward the inner bottom surface side (downward in fig. 6) oflower case 12, and firstextended portion 32a extended outward from the inner bottom surface side end portion oflower case 12

Second extension portion 32b extending to a position facing common fixed contact 6 (obliquely downward to the right in fig. 6), andthird extension portion 32c extending from the end ofsecond extension portion 32b on the common fixedcontact 6 side to a position substantially the same as that ofconnection portion 31b along common fixed contact 6 (upward in fig. 6) substantially in parallel withfirst extension portion 32a, andthird extension portion 32c being inclined toward common fixed contact 6 (see fig. 5). The distal ends of the third extendingportions 32c of the pair of U-shapedelastic pieces 32 are bent in a direction to approach each other, and the bent portions constitute the first movablecontact point portions 3a that are always in sliding contact with the common fixedcontact 6. Similarly, the distal ends of the third extending portions of the pair of U-shapedelastic pieces 33 are also bent in the direction to approach each other, and the bent portions constitute the secondmovable contact portion 3b that is in slidable contact with and separated from the switching fixed contacts (the NO fixedcontact 7 and the NC fixed contact 8).

As shown in fig. 2 to 4, the firstmovable contact portion 3a and the secondmovable contact portion 3b of themovable contact piece 3 are disposed in a dispersed manner inside and outside thehollow portion 4a of thecoil spring 4. That is, the paired U-shapedelastic pieces 32 on one end side of themovable contact piece 3 are inserted into thehollow portion 4a of thecoil spring 4 such that the secondextended portion 32b is the inner bottom surface side of thelower case 12, and the open portion (opening portion) between the firstextended portion 32a and the thirdextended portion 32c is directed toward thepressing portion 21 side of theoperation member 2, i.e., the upper side in fig. 2. The pair of firstmovable contact portions 3a sandwich the common fixedcontact 6 standing in thehollow portion 4 a. As described above, since the common fixedcontact 6 is offset from the center of thespring mounting portion 12a, even if the U-shapedelastic piece 32 for bringing the firstmovable contact portion 3a into sliding contact with the common fixedcontact 6 is disposed in thehollow portion 4a, a sufficient space can be secured between the U-shapedelastic piece 32 and thedisc spring 4. At this time, since the common fixedcontact 6 approaches thedisc spring 4 on the right side in fig. 2, there is a possibility that thedisc spring 4 comes into contact with the common fixedcontact 6 due to an impact or the like. In this case, even if thecoil spring 4 made of a conductive metal material is in contact with the common fixedcontact 6, the common fixedcontact 6 and the firstmovable contact portion 3a are always in conduction, and therefore, the output of the electric signal is not adversely affected. As shown in fig. 2, the secondmovable contact portion 3b of the U-shapedelastic piece 33 paired on the other end side of themovable contact piece 3 sandwiches the NC fixedcontact 8 when the operatingmember 2 is not operated, and when the operatingmember 2 is press-fitted with a predetermined stroke, the secondmovable contact portion 3b is separated from the NC fixedcontact 8 as shown in fig. 4, and sandwiches the NO fixedcontact 7.

In the push-button switch configured as described above, since the operatingmember 2 is pressed to the uppermost position by the urging force of thecoil spring 4 in the non-operation state, as shown in fig. 2, the firstmovable contact portion 3a is brought into contact with the common fixedcontact 6, and the secondmovable contact portion 3b is brought into contact with the NC fixedcontact 8, that is, the NC fixedcontact 8 and the common fixedcontact 6 are brought into conduction by themovable contact piece 3. However, in this state, the secondmovable contact portion 3b does not contact the NO fixedcontact 7, and therefore conduction between the NO fixedcontact 7 and the common fixedcontact 6 is interrupted, and the push switch is turned OFF.

When thepressing portion 21 shown in fig. 2 is pressed by an actuator not shown, thecoil spring 4 is compressed in the housing 1, and themovable contact piece 3 moves down integrally with the operatingmember 2, so that the firstmovable contact portion 3a slides while maintaining a sandwiched posture with respect to the common fixedcontact 6. As shown in fig. 4 and 5, the secondmovable contact portion 3b is separated from the NC fixedcontact 8 and sandwiches the NO fixedcontact 7. As a result, the conduction between NC fixedcontact 8 and common fixedcontact 6 is released, NOfixed contact 7 and common fixedcontact 6 are brought into a conductive state, and the contact switching from OFF to ON is performed. Then, when the pushing operation force to the pushingportion 21 is removed, the operatingmember 2 is pushed up by the elastic restoring force of thecoil spring 4, and therefore, the secondmovable contact portion 3b is separated from the NO fixedcontact 7 and automatically returns to the original OFF state in which it is in sliding contact with the NC fixedcontact 8. In this way, when the secondmovable contact portion 3b slides between the NO fixedcontact 7 and the NC fixedcontact 8 in accordance with the movement of the operatingmember 2 to perform contact switching in the ON/OFF state, in the present embodiment, as shown in fig. 5, the NO fixedcontact 7 and the NC fixedcontact 8 include the gap portions whose outer surfaces and inner surfaces are the same surface, so that the contact pressure can be smoothly slid in a state where it is kept constant, and good contact switching position accuracy can be ensured.

Further, with respect to the holdingportion 31 of themovable contact piece 3, the pair of U-shapedelastic pieces 32 having the firstmovable contact portion 3a and the pair of U-shapedelastic pieces 33 having the secondmovable contact portion 3b are disposed in a dispersed manner inside and outside thehollow portion 4a of thecoil spring 4, and the upper end portion of thecoil spring 4 abuts on the holdingportion 31 to urge the operatingmember 2 side, so that themovable contact piece 3 is less likely to tilt with respect to the operatingmember 2, and therefore the firstmovable contact portion 3a and the secondmovable contact portion 3b are less likely to tilt, thereby improving the contact switching position accuracy. In the present embodiment, the top surface of the operatingmember 2 and the holdingportion 31 of themovable contact piece 3 are opposed to each other on the same plane, so that themovable contact piece 3 is less likely to be inclined with respect to the operatingmember 2, so that the contact switching position accuracy is further improved. In the present embodiment, the upper end portion of thecoil spring 4 is directly brought into contact with the holdingportion 31 to bias themovable contact piece 3 toward the operatingmember 2, but themovable contact piece 3 may be biased toward the operatingmember 2 by a spacer or the like, not shown, between the holdingportion 31 and the upper end portion of thecoil spring 4. Since the holding position (of holding portion 31) ofmovable contact piece 3 is not directly below pressingportion 21 but is shifted to the NO fixedcontact 7 and NC fixedcontact 8 sides, pressingportion 21 can be disposed on the end of common fixedcontact 6 side of housing 1 (the end on the right side of housing 1 in fig. 1, 2, and 4).

As described above, according to the push switch of the present embodiment, the common fixedcontact 6 standing along the pushing direction of the pushingportion 21 is disposed in thehollow portion 4a of thecoil spring 4, and thus the switching fixed contacts (the NO fixedcontact 7 and the NC fixed contact 8) can be disposed in the vicinity of thecoil spring 4 on the outer side of thehollow portion 4 a. That is, since it is not necessary to largely extend themovable contact piece 3 to the side of thecoil spring 4, even if theoperation member 2 is inclined at the time of press-fitting operation, the contact position of the secondmovable contact portion 3b with respect to the switching fixedcontacts 7 and 8 is hardly shifted. Therefore, even if the operatingmember 2 is inclined, the push switch is less likely to be displaced in the timing of the contact switching operation, and the accuracy of the contact switching position of ON or OFF is improved. Further, since the operatingmember 2 and themovable contact piece 3 can be made smaller, it is also easy to adapt to the case where the push switch is made smaller.

In the push-button switch according to the present embodiment, themovable contact portions 3a and 3b of themovable contact piece 3 are formed at the distal ends of the U-shapedelastic pieces 32 and 33 so as to sandwich the common fixedcontact 6 and the switching fixedcontacts 7 and 8, and therefore, themovable contact portions 3a and 3b and the corresponding fixedcontacts 6 to 8 are in stable contact with each other, and reliability is high. That is, by providing the U-shapedelastic pieces 32 and 33, even if themovable contact 3 is not increased in size, since the movable contact operates within a sufficient elastic range, it is possible to reliably bring themovable contact portions 3a and 3b into elastic contact with the corresponding fixedcontacts 6 to 8. Further, by raising the common fixedcontact 6 in sliding contact with the firstmovable contact portion 3a from a position outside the center of thespring mounting portion 12a, a sufficient space is secured between thecoil spring 4 and the U-shapedelastic piece 32 in thehollow portion 4a, so that interference between the U-shapedelastic piece 32 and thecoil spring 4 can be reliably avoided. Further, in the above-described embodiment, the firstmovable contact portion 3a is disposed in thehollow portion 4a of thecoil spring 4 so that the open side of the U-shapedelastic piece 32 faces the operatingmember 2, but the present invention is not limited to this, and for example, the U-shapedelastic piece 32 may be positioned in thehollow portion 4a on thepressing portion 21 side so that the open side of the U-shapedelastic piece 32 faces the lower side which is thespring attachment portion 12a side.

In the above embodiment, the NO fixed contact and the NC fixed contact are disposed in the housing as the switching fixed contact of the second fixed contact, but the switching fixed contact may be configured by only one of the NO fixed contact and the NC fixed contact. The switching fixed contact may be disposed in a hollow portion of a return elastic member such as a coil spring, and the common fixed contact may be disposed outside the hollow portion. The first fixed contact may not be a common fixed contact, and the second fixed contact may not be a switching fixed contact, and the first fixed contact and the second fixed contact may be fixed contacts each having an insulating portion such as resin provided at an upper end portion (operation member side), for example. Therefore, in such a configuration, when the pressing portion of the operating member is pressed, the first movable contact portion is brought into sliding contact with the first fixed contact, and the second movable contact portion is brought into sliding contact with the second fixed contact, whereby the first fixed contact and the second fixed contact are brought into conduction, and the ON state is established. In such a configuration, the first movable contact portion and the second movable contact portion can switch the conductive state between the first fixed contact and the second fixed contact in accordance with the pushing operation of the pushing portion. The insulating portion may be provided at a lower end portion of the fixed contact, and the pressing portion may be pressed to switch the insulating portion from the ON state to the OFF state. Further, the shape of the movable contact member may be appropriately selected, and for example, the movable contact portion may be formed at the tip end portions of a pair of opposed L-shaped elastic pieces provided in the movable contact member.

Claims (9)

1. A push button switch comprising:

an operation member having a pressing portion to which a pressing operation is performed;

a housing for holding the operating member and allowing the operating member to reciprocate;

a movable contact member held by the operating member and reciprocated in the housing;

a restoring elastic member that is disposed in the housing on a side that extends in a pressing operation direction of the pressing portion and that pushes back the operation member to a non-operation position;

a first fixed contact and a second fixed contact disposed within the housing,

wherein,

the movable contact member has a first movable contact portion in sliding contact with the first fixed contact and a second movable contact portion in sliding contact with the second fixed contact,

the first movable contact part and the second movable contact part switch the conduction state between the first fixed contact and the second fixed contact in accordance with the press-in operation of the pressing part,

the push-button switch is characterized in that,

the elastic member for restoration has a hollow portion, and the first fixed contact is raised in the hollow portion along a pressing operation direction of the pressing portion.

2. The push button switch according to claim 1,

the resilient member for recovery is a coil spring.

3. The push button switch according to claim 1,

the first fixed contact is a common fixed contact which is always in sliding contact with the first movable contact portion, the second fixed contact is a switching fixed contact which is in sliding contact with and separated from the second movable contact portion,

the common fixed contact is disposed in the hollow portion.

4. The push button switch according to claim 3,

the switching fixed contact is composed of a first switching fixed contact and a second switching fixed contact,

the first switching fixed contact and the second switching fixed contact are arranged at positions separated from each other along a pressing operation direction of the pressing portion.

5. The push button switch according to claim 2,

the movable contact member has a holding portion held on the operating member,

the first movable contact portion and the second movable contact portion are coupled to the holding portion, respectively, and the first movable contact portion and the second movable contact portion are disposed inside and outside the hollow portion of the restoring elastic member in a dispersed manner, and the holding portion located between the first movable contact portion and the second movable contact portion is biased toward the operating member side by one end portion of the restoring elastic member.

6. The push button switch according to claim 5,

the first movable contact portion is formed in a shape sandwiching the first fixed contact, and the second movable contact portion is formed in a shape sandwiching the second fixed contact.

7. The push button switch according to claim 6,

the movable contact member is formed of a metal plate, and the holding portion is plate-shaped,

a pair of substantially U-shaped elastic pieces having plate surfaces facing each other at a predetermined interval are connected to both sides of the holding portion, respectively, and portions bent in directions in which distal ends of the U-shaped elastic pieces approach each other constitute the movable contact portions sandwiching the corresponding fixed contacts.

8. The push button switch according to claim 7,

the first movable contact portion is disposed in the hollow portion of the resilient member for return such that the open side of the pair of U-shaped resilient pieces faces the operating member side.

9. The push button switch according to claim 8,

the other end portion of the elastic member for restoration is held by a mounting portion provided in the housing, and the first fixed contact located in the hollow portion is raised from a position shifted from the center of the mounting portion in a direction away from the second fixed contact located outside the hollow portion.

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