A switch driving portion includes a lever link mechanism which as a pair of lever members respectively rocking about a rocking fulcrum by interlocking with a push button portion when the push button portion is pushed and arranged so as to be faced each other and in which the both lever members are connected each other at their faced ends by joint members so that they can be folded and slid and a switch operating member for opening or closing a built-in switch when the lever link mechanism is rocked by pushing in the push button portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a push button switch used for an elevator switch and the like.

2. Description of the Related Art

FIGS. 33 and 34show a conventional push button switch. The push button switch S-1has a case90and a setting portion100is set to the case90. Moreover, two fixed terminals91are set to the backs of opposite side faces of the case90and these fixed terminals91respectively have a fixed contact point at their upper faces.

Furthermore, an operating shaft92is movably set to the case90, and a movable piece93is set to the inner end of the operating shaft92so that the fixed terminals91are faced each other and has a movable contact point93aopposite to the fixed contact point91a. Furthermore, a diffusion plate95, character plate94, and key top96are set to the outer end of the operating shaft92so that they are overlapped each other.

Furthermore, the operating shaft92is raised by a return spring97and the movable contact point93aseparates from the fixed contact point91a.

A lamp98is set to a lamp holder99. Then, by setting the case90to a setting destination member (not illustrated) while housing the lamp98and lamp holder99in the case90, the push button switch S-1is constituted. The push button switch S-1uses a directly-under illumination system in which the lamp98is set directly under a push button portion constituted by the diffusion plate95, character plate94, and key top96.

Moreover, by pushing in the key top96of the push button portion by a finger and thereby, pushing in the operating shaft92against the return spring member97, the movable contact point93aof the movable piece93contacts wit the fixed contact point91aof the fixed terminal91, the contact point closes, and the switch is turned on.

When the lamp98lights up, it illuminates the diffusion plate95from its back. Therefore, characters on the character plate94can be seen from the outside of the key top96by the light passing through the diffusion plate95.

However, because the above conventional push button switch S-1is constituted so as to push the key top96, directly move the movable contact point93a, close the contact point portion constituted by the movable contact point93aand fixed contact point91a, and turn on the switch. Therefore, the key top96requires a movement stroke equal to or more than a contact point gap necessary to open or close the contact point of the contact point portion, that is, the opening distance between the contact points91aand93for the contact point portion to be safely turned off. Thus, there is a problem that the whole switch becomes thick.

SUMMARY OF THE INVENTION

The present invention is made to solve the above problems and its object is to provide a push button switch whose thickness can be decreased.

To achieve the above object, a push button switch of the present invention uses a push button switch in which a push button portion and a switch portion are housed in a case so as to open or close the switch portion by pushing in the push button portion, comprising a lever-link mechanism having a pair of lever members which rock about a rocking fulcrum by interlocking with the push button portion when the push button portion is pushed in and are arranged so as to be faced each other, in which the both lever members are connected each other so that they can be folded and slid at their facing ends faced each other and a switch operating member for opening or closing the switch portion when the lever link mechanism is rocked because the push button portion is pushed in.

In the case of the above configuration, by pushing in the push button portion, the push button portion is moved in parallel in its pushed direction by a lever link mechanism and when the lever ling mechanism is operated by pushing in the push button portion, lever members constituting the lever link mechanism are rocked about a rocking fulcrum and thereby, it is possible to operate a switch portion by a switch operating member.

A contact-point gap necessary to open or close the switch portion, that is, an opening distance between contact points for the switch portion to be safely turned off is different from the movement stroke of the push button portion. A movement stroke equal to or more than an opening distance between contact points for a contact portion to be safely turned off has been necessary for a push button portion (key top) so far. However, because the difference between a predetermined movement stroke of the push button portion and a stroke (contact point gap) necessary to open or close the contact point of a switch portion can be adjusted by selecting the lever ratio of a lever member, it is possible to securely operate the switch portion by a small movement stroke of the push button portion.

That is, to securely operate the switch portion by making the movement stroke of the push button portion smaller than the stroke (contact point gap) necessary to open or close the contact point of the switch portion, it is possible to decrease the thickness of the push button switch.

Thus, because the switch portion can be securely operated by making the movement stroke of the push button portion smaller than the stroke (contact point gap) necessary to open or close the switch portion, it is possible to decrease the thickness of the push button switch.

Particularly, because the lever link mechanism has a pair of lever members which rock about a rocking fulcrum and are connected each other so that they can be folded and slid at their facing ends, it is unnecessary to use an elevating link in which two links having been generally used are slidably connected each other at their intermediate portions and it is possible to decrease the thickness of a push button switch.

In this case, the push button portion is constituted by fitting a diffusion plate, character plate, and key top to an operating shaft while lapping them and fixing them to the operating shaft. Moreover, the switch portion corresponds to a tactile switch or mechanical switch serving as a built-in switch.

Moreover, in the case of the above push button switch of the present invention, a pair of lever members is constituted by a wire.

According to the above configuration, a pair of lever members becomes strong, it is tough in shock and it is not broken though a synthetic-resin lever member is weak in shock and it may be broken. Thus, it is possible to contribute to a long-term use of a push button switch.

Moreover, in the case of the above push button switch of the present invention, one lever member is fixed to one joint member at the faced end of one arm and the faced end of the other arm is slidably connected to the other joint member of the other arm, the other lever member is fixed to the other joint at the faced end of one arm, and the faced end of the other arm is slidably connected to one joint to form a lever folding point on a straight line connecting the faced end of the other arm of one lever member with the faced end of the other arm of the other lever member.

According to the above configuration, by pushing in a push button portion, it is possible to move the push button portion in parallel by a lever link mechanism in its pushed direction, rock one and the other lever members constituting the lever link mechanism about their respective rocking fulcrums when the push button portion is pushed in and thereby, the lever link mechanism operates, and joint-move the lever members at a lever folding point. Therefore, it is possible to easily exhibit the parallel-movement function of the lever link mechanism.

Moreover, it is possible to constitute a simple and low lever link mechanism and contribute to decrease of a push button switch in thickness.

Furthermore, in the case of the above push button switch of the present invention, a muffling member for generating a spring force in the direction opposite to the pushed direction of a push button portion when the push button portion is pushed in is set between a switch operating member and a switch portion.

According to the above configuration, because the muffing member is set between the switch operating member and switch portion, when the switch portion is pushed through the muffling member, a pushing force for the switch operating member to push the switch portion is added to the pushing force of the switch operating member. However, because the spring force of the muffling member acts in the direction opposite to the pushed direction of the switch portion, that is, the spring force of the muffling member acts so as to cancel the pushing force of the switch operating member, the collision speed of the movable contact point of the switch portion to the fixed contact point of the switch portion decreases, the collision load between the contact points decreases, and it is possible to eliminate a noise of “click” which is generated when the movable contact point contacts with the fixed contact point.

Moreover, in the case of the above push button switch of the present invention, an illuminating portion for illuminating the front of a push button portion is set to a case so as to cover a switch operating member.

According to the above configuration, it is possible to realize a low structure by lapping a switch operating member on an illuminating portion and it is possible to contribute to decrease of a push button switch in thickness.

In this case, the illuminating portion is constituted by a reflection case, light guiding portion held by the reflection case, and LED module serving as a light source for supplying light to the light guiding portion.

Moreover, in the case of the above push button switch of the present invention, an elastic stopper member with which a push button portion contacts when the push button portion is pushed in is set to a case.

According to the above configuration, when normally pushing the push button portion, the push button portion contacts with a stopper member and because the push button portion can withstand the pressure of the stopper, it is possible to prevent the pressure from influencing components.

Moreover, in the case of the above push button switch of the present invention, a shock absorbing member is set between a case and a clamp of the case.

According to the above configuration, when normally pushing the bush button portion, the bush button portion contacts with the stopper member and is able to withstand the pressure of the stopper member. However, when pushing the bush button at an excessive pressure, the bush button collides with the stopper member and thereby, the stopper member is deflected, the push button portion is supported by the case, and the case is supported by the shock absorbing member. Therefore, it is possible to prevent the push button switch from being broken due to the excessive pressure.

In this case, the shock absorbing member uses an elastic plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A push button switch (embodiment) of the present invention is described below by referring to the accompanying drawings.

FIG. 1is a perspective view of a push button switch of the present invention,FIG. 2is a perspective view of the push button switch while it is set to a clamp,FIG. 3is a schematic perspective view of the push button switch while it is disassembled,FIG. 4is a sectional view taken along the line Y—Y inFIG. 2, andFIG. 5is a sectional view taken along the line Z—Z in FIG.2. For convenience sake of description, anteroposterior direction, horizontal direction, and vertical direction are set as illustrated.

As shown inFIGS. 1to3, an embodiment of a push button switch of the present invention has a case1, a built-in switch2serving as a switch portion to be housed in the case1, a switch driving portion3for operating the built-in switch2set in the case1, an illuminating portion4, and a push button portion5.

As shown inFIG. 10, the case1has a case body1F and the case body1F is formed like a box having a bottom face (lower face)1A, front and rear faces1B and1C, and left and right faces1D and1E and the upper face of the case body is open. Moreover, a securing protrusion1ais formed on the left and right faces1D and1E respectively.

Moreover, as shown inFIGS. 6 and 10, the following portions are formed on the inside1A-1of the bottom face1A of the case body1F: a lever-member setting portion6, switch setting portion7, muffling-member setting portion75, switch-operating-member setting portion76, operating-shaft setting portion22, stopper-member setting portion56, and reflection-case setting portion78. Moreover, as shown inFIG. 11, a substrate setting portion54and a shock-absorption-member setting portion77are formed on the outside1A-2of the bottom face1A.

The lever-member setting portion6is constituted by a left lever-member setting portion6L serving as one lever-member setting portion and a right lever-member setting portion6N serving as the other lever-member setting portion.

The left lever-member setting portion6L is constituted by a lever-inserting long groove7A formed along the left face1D, a hole8formed at the front and rear of the lever-inserting long groove7A respectively at the inside1A-1side of the bottom face1A as shown inFIG. 6, and a lever-arm inserting grooves9F and9R formed at the front and rear at the outside1A-2side of the bottom face1A and front and rear joint-member housings10F and10R serving as holes extending from the inside1A-1side to the outside1A-2side of the bottom face1A as shown in FIG.11.

The lever-arm inserting grooves9F and9R has crank-shaped grooves11F and11R formed on the outside1A-2of the bottom face1A as shown inFIG. 11, the grooves11fand11R have horizontal grooves12F and12R connected to the hole8along the horizontal direction, vertical grooves13F and13R connected to the horizontal grooves12F and12R along the anteroposterior direction, horizontal grooves14F and14R connected to the vertical grooves13F and13R and connected to the joint-member housings10F and10R, and protrusions15F and15R are formed on the vertical grooves13F and13R to constitute front and rear lever fulcrum supports16F and16R.

Moreover, though the right lever-member setting portion6N has the same configuration as the left lever-member setting portion6L, the lever-arm inserting grooves9F and9R are formed in the reverse direction. Therefore, front and rear lever fulcrum supports16F and16R are formed in the reverse direction.

Furthermore, as shown inFIG. 10, the switch setting portion7is constituted by forming a securing hole17aat the bottom of a concave portion17formed at the central portion of the inside1A-1side of the bottom face1A and protrusively forming a cantilever-shaped securing portion18at four corners at the bottom of the concave portion17. A pawl18ais formed on the securing portion18.

Furthermore, the stopper-member setting portion56is formed at four corners of the inside1A-1of the case1as shown in FIG.6.

Furthermore, the switch-operating-member setting portion76is constituted by forming a hole20and a concave portion21at the both sides of the concave portion17of the switch setting portion7as shown in FIG.10. The hole20is connected to the lever-inserting long groove7A of the left lever-member setting portion6L and the concave portion21is connected to the lever-inserting long groove7A of the right lever-member setting portion6N.

Furthermore, the operating-shaft setting portion22is formed along insides of the front and rear faces1B and1C and left and right faces1D and1E of the case body1F as shown in FIG.10and the front and rear of the portion22are formed as grooves23. Furthermore, a pair of securing protrusions25is formed on insides of the front and rear faces1B and1C. Furthermore, a pair of guiding protrusions27is formed on insides of the left and right faces1D and1E.

Furthermore, a rectangular lead-wire hole29is formed from the bottom face1A of the case body1F up to the left face1D.

The built-in switch2is constituted by a tactile switch as shown inFIG. 15, which deflects a built-in movable electrode (not illustrated) constituted by a dome-shaped spring material by pushing a push button30serving as an external operating portion, turns on the movable electrode by bringing a movable contact point (not illustrated) of the movable electrode into contact with a fixed contact point (not illustrated), restores the movable electrode by its return force, and turns off the movable electrode. A securing protrusion32is protrusively formed on the back of a case31of the built-in switch2(refer toFIG. 8) and terminal leads33aand33bare set to side faces of the case31.

Moreover, the built-in switch2is set to the switch setting portion7by inserting and securing the securing protrusion32into and at the securing hole17aof the switch setting portion7as shown in FIG.8and securing the pawl18aof the securing portion18at the shoulder of the case31as shown by a virtual line in FIG.10. Furthermore, a printed circuit board55is set to the substrate setting portion54formed at the outside1A-2side of the bottom face1A of the case1as shown in FIG.5and the terminal leads33aand33bof the built-in switch2are connected to the printed circuit board55.

As shown inFIG. 3, the switch driving portion3has left and right (one and the other) lever members34L and34N, joint members44F and44R for connecting the lever members34L and34N each other, a movable-piece-shaped switch operating member48made of an elastic material (spring-plate material), and a muffling member51formed by a leaf spring. Moreover, left and right lever members34L and34N and the joint members44F and44R constitute a lever link mechanism F (refer to FIG.12).

The left (one) lever member34L is formed by bending a metallic wire as shown in FIG.12. That is, the lever member34L has a linear connecting shaft35, an arm portion38F serving as one arm bent and formed into a crank shape at the both ends of the connecting shaft35, and an arm38R serving as the other arm bent and formed into a crank shape at the rear end of the connecting shaft35.

Moreover, the arm38F has a connecting portion39F orthogonal to the connecting shaft35, a support40F connected to the connecting portion39F and parallel with the connecting shaft35, a connecting portion41F connected to the support40F and orthogonal to the connecting shaft35, and a pin portion42F connected to the connecting portion41F, parallel with the connecting shaft35, and serving as one lever-side fixing portion.

Furthermore, the arm38R has a connecting potion39R orthogonal to the connecting shaft35, a support40R connected to the connecting portion39R and parallel with the connecting shaft35, a connecting portion41R connected to the support40R and orthogonal to the connecting shaft35, and pin portion42R connected to the connecting portion41R, parallel with the connecting shaft35, and serving as one lever-side rocking portion.

Furthermore, the supports40F and40R of the arms38F and38R are located on a parallel line “a” parallel with the connecting shaft35, the connecting portion41F is made shorter than the connecting portion41R, and the axis line “b” of the pin portion42F is displaced from the axis line “c” of the pin portion42R by a dimension “x”.

Furthermore, the right (the other) lever member34N is constituted the same as the left (one) lever member34L is. Furthermore, the right lever member34N is faced with the left lever member34L by rotating a lever member same as the left lever member34L by 180° in the horizontal direction, the pin portion42F of the arm38F serving as one arm of the right lever member34N becomes the other lever-side fixing portion, and the pin portion42R of the arm portion38R serving as the other arm portion becomes the other lever-side sliding portion. The sliding portion is provided with the same symbol as the left lever member34L and its description is omitted.

The joint members44F and44R have a block-shaped member body44A as shown inFIGS. 13 and 14, a pin inserting hole45is formed on the inside44aof the member body44A vertically to the inside44aand moreover, a pin inserting groove46connected to the pin inserting hole45is formed on the inside44a, and the hole45and groove46constitute a joint fixing portion. Moreover, a slide groove potion47serving as a joint-side sliding portion parallel with the pin-inserting-hole potion45is formed on an end face44borthogonal to the inside44aof the member body44A.

The switch operating member48has a strip plate48A formed by a metal leaf as shown inFIG. 16 and aprotruded switch operating portion49is formed at the central portion of the plate48A. Moreover, lever member hangings50L and50N serving as lever-member setting portions are formed at the both ends of the plate port48A.

As shown inFIG. 17, the muffling member51has a strip plate51A formed by a metal leaf as shown in FIG.17and the central portion of the plate51A is formed as a switch contact portion52and the both ends of the plate51A are formed as supports53.

Moreover, as shown inFIGS. 12 and 13, the joint member44F is set to the left (one) lever member34L by inserting the pin portion42F of the arm38F of the member34L into the pin inserting hole45of the joint member44F and the connecting portion41F into the pin inserting groove46and the joint member44R is set to the right (the other) lever member34N by inserting the pin portion42F of the arm38F of the member34N into the pin inserting hole45of the joint member44R and the connecting portion41F into the pin inserting groove46.

Furthermore, the left lever member34L is set to the left-side lever-member setting portion6L of the case1and the right lever member34N is set to the right-side lever-member setting portion6N of the case1and the left and right lever members34L and34N are flexibly connected each other by the joint members44F and44R.

That is, the connecting shaft35of the left lever member34L is inserted into the left lever-inserting long groove7A of the case1as shown in FIG.6and the arm38F of the left lever member34L is inserted into the lever-arm inserting-groove9F of the case1as shown in FIG.7. In this case, the connecting portion39F of the arm38F is inserted into the horizontal groove12F of the lever-arm inserting groove9F, the support40F is inserted into the lever fulcrum support16F, and the connecting portion41F is inserted into the horizontal groove14F. Moreover, the joint member44F is housed in the joint member housing10F.

Furthermore, as shown inFIG. 7, the arm38R of the left lever member34L is inserted into the lever-arm inserting groove9R of the case1. In this case, the connecting portion39R of the arm38R is inserted into the horizontal groove12R of the lever-arm inserting groove9R, the support40R is inserted into the lever fulcrum support16R, and the connecting portion41R is inserted into the horizontal groove14R. Furthermore, the supports40F and40R constitute the rocking fulcrum P of the left lever member34L.

Furthermore, the connecting shaft35of the right lever member34N is inserted into the right lever inserting groove7A of the case1as shown in FIG.6and the arm38R of the right lever member34N is inserted into the lever-arm inserting groove9R of the case1as shown in FIG.7. In this case, the connecting portion39R of the arm38R is inserted into the horizontal groove12R of the lever-arm inserting groove9R, the support40R is inserted into the lever fulcrum support16R, and the connecting portion41R is inserted into the horizontal groove14R. Moreover, the joint member44R is housed in the joint member housing10R.

Furthermore, the arm38F of the right lever member34N is inserted into the lever-arm inserting groove9F of the case1. In this case, the connecting portion39F of the arm38F is inserted into the horizontal groove12F of the lever-arm-inserting groove9F and the support40F is inserted into the lever fulcrum support16F, and the connecting portion41F is inserted into the horizontal groove14F. Furthermore, the supports40F and40R form the rocking fulcrum P of the right lever member43N.

Furthermore, the pin portion42R of the left lever member34L is slidably inserted into the slide groove47of the joint member44R and the pin portion42R of the right lever member34N is slidably inserted into the slide groove47of the joint member44R. A lever folding point Q for the left and right lever members34L and43N is located on a straight line connecting the pin portion42R of the left lever member34L with the pin portion42R of the right lever member34N (refer to FIG.7).

Furthermore, as shown inFIG. 4, a muffling member51is set to a reflection member setting portion75by setting the support53of the member51to the concave portion19of the reflection member setting portion75of the case1while bringing the switch contact portion52at the central portion of the member51into contact with the push button30of the built-in switch2.

Furthermore, the switch operating member48is located at the switch-operating-member setting portion76by hanging the left lever-member hanging portion50L on the connecting shaft35of the left lever member34L and the right lever-member hanging portion50N on the connecting shaft35of the right lever member34N as shown inFIG. 6while bringing the protruded switch operating portion49of the member48into contact with the switch contact portion52of the muffling member51.

Furthermore, a stopper member57made of an elastic material shown inFIG. 22is set to the stopper-member setting portion56formed on the inside1A-1of the bottom face1A of the case1.

The illuminating portion4is constituted by a reflection case60serving as a reflection member shown inFIG. 18, a reflection plate60A serving as a reflection member shown inFIG. 3, a light guiding plate61serving as a light guiding member shown inFIG. 19, and an LED module62serving as a light source shown in FIG.20.

Moreover, the LED module62is set to the side end of the reflection case60. The LED module62is constituted by horizontally arranging a plurality of LEDs62B on a setting substrate62A and each LED62B faces the side end of the light guiding plate61. Furthermore, the light guiding plate61is housed in the reflection case60.

Furthermore, the reflection case60, reflection plate60A, light guiding plate61, and LED module62formed into a unit are set to the reflection-case setting portion78of the case1by turning the reflection case60downward as shown in FIG.4.

The push button portion5is constituted by a key top64made of a transparent resin, character plate65, diffusion plate66, and operating shaft67. A securing portion64ais formed around the key top64as shown in FIG.3.

As shown inFIG. 21, the operating shaft67has a quadrangular-frame-shaped shaft body67A, and a bush-button catching portion68is formed on insides of left and right faces67aand67bof the shaft body67A and a sliding groove71is formed on outer fades of the left and right faces67aand67bfrom upper margins of the outsides downward.

Moreover, a lever contact portion69is formed at lower ends of the left and right faces67aand67bof the shaft body67A. Furthermore, a securing portion70is formed at upper margins of insides of front and rear faces64cand64dof the shaft body67A.

Furthermore, the diffusion plate66and character plate65are overlapped and housed in the operating shaft66to catch the character plate65and diffusion plate66by the push-button catching portion68. Furthermore, by inserting the key top64into the operating shaft67and securing the securing portion70of the operating shaft67at the securing portion64aof the key top64, the key top64, character plate65a, and operating shaft67are formed into a unit.

Furthermore, the operating shaft67thus formed into the unit is inserted into the case1, guiding protrusions27of the left and right faces1D and1E of the case1are slidably inserted into the sliding groove71on the outside of the left and right faces67aand67bof the operating shaft67, and the lever contact portion69formed on the operating shaft67is rotatably brought into contact with the connecting shaft35of the left and right lever members34L and34N as shown in FIG.5.

In this case, the resilience of a movable electrode formed by the spring material of the built-in switch2raises the push button30of the built-in switch2, raises the muffling member51and movable piece48along the push button30, and moreover raises the bush button portion5.

Therefore, the guide protrusion27of the case1is hooked on the lower end71aof the sliding groove71of the operating shaft67and the operating shaft67corresponds to pushing-up by the resilience of the movable electrode to hold the pushing-down stroke of the push button portion5.

Moreover, because the muffling member51and switch operating member48are pushed up by the push button30, the left lever member34L rotates about its rocking fulcrum clockwise as shown inFIG. 26, the right lever member34N rotates about its rocking fulcrum counterclockwise as shown inFIG. 26, and the lever folding point Q of the left and right lever members34L and34N is lowered.

Therefore, as shown inFIG. 9, in the push button switch S constituted as described above, a flat shock absorbing member73made of an elastic material is set to the shock-absorption-member setting portion77of the outer face1A-2of the case1.

As shown inFIG. 25, a clamp74has-a clamp body74F constituted by forming vertical walls74B and74C on left and right margins and setting portions74B and74C on left and right vertical walls74B and74C on a face74A, in which an opening79is formed on the face74A and a securing hole80is formed on the left and right vertical walls74B and74C respectively.

Moreover, as shown inFIG. 2, the push button switch S constituted as described above is set to the clamp74by securing the securing protrusion1aof the case1to the securing hole80of the clamp74. Furthermore, the push button switch S is set to a panel U by inserting the key top64to the opening81of the panel U along the back side of the panel U while protruding the key top64outward, bringing the clamp74into contact with the outer face (back)1A-2side of the push button switch S, bringing the clamp74into contact with the back of the panel U, and setting the clamp74to the panel U by a screw member (not illustrated) at setting portions74B and74C of the clamp74.

In this case, as shown inFIG. 28, the shock absorbing member73contacts with the face74A of the clamp74, the push button portion5is raised by the resilience of the movable electrode, and the lower end of the operating shaft67has a gap T1between the lower end and the stopper member57set to the case1and moreover, a gap T2is present between the push button portion5and the light guiding plate61of the illuminating portion4. Moreover, the gap T1is set to a dimension smaller than the gap T2.

Then, operations of the push button switch S constituted as described above are described below.

By connecting a connector82connected to the printed circuit board55through a lead wire82ato a power source, power is supplied to the built-in switch2connected to the printed circuit board55.

When the operating shaft67is pushed in by pushing in the key top64of the push button portion5by a finger, the lever contact portion69formed on the operating shaft67pushes in the connecting shaft35of the left and right lever members34L and34N. Thereby, the left lever member34L rotates counterclockwise about the rocking fulcrum P of the member34L as shown inFIG. 26, the right lever member34N rotates clockwise about the rocking fulcrum of the member34N as shown inFIG. 26, and the lever folding point Q for the left and right lever members34L and34N is raised as shown in FIG.27. Therefore, the push button portion5moves in parallel.

Thus, because the lever folding point Q for the left and right lever members34L and34N is raised, the switch operating member48moves in the pushed direction of the push button portion5to push in the push button30of the built-in switch2through the muffling member51. Therefore, the movable electrode is pushed in and inverted and the movable contact point of the movable electrode contacts with the fixed contact point to turn on the switch.

In this case, a noise of “click” generated when the movable electrode of the built-in switch2is pushed in and inverted and the movable point of the movable electrode contacts with the fixed contact point is eliminated by the muffling member51.

That is, when the muffling member51is absent and the switch operating member48is set so as to directly contact with the push button30of the built-in switch2, the switch operating member48directly pushes in the push button30of the built-in switch2and thereby, a force for the switch operating member48to push the push button30is added to the pushing force of the push button30, the collision speed of the movable contact point of the movable electrode of the built-in switch2against the fixed contact point is increased, and the collision load between the contact points is increased to generate noises.

However, because the muffling member51is present between the switch operating member48and the push button30of the built-in switch2, the switch operating member48pushes in the push button30of the built-in switch2through the muffling member51and thereby, the spring force of the muffling member51acts in the direction opposite to the pushed direction of the push button30, that is, the switch operating member48acts so as to cancel the pressure for the switch operating member48to push the bush button30, the collision speed of the movable contact point of the movable electrode of the built-in switch2against the fixed contact point decreases, the collision load between the contact points decreases, and noises are eliminated.

Moreover, the LED62B of the LED module62emits light, the light is diffused by the light guiding plate61, spreads in all directions, and is reflected from the reflection case60to illuminate diffusion plate66from its back. Therefore, characters on the character plate65are viewed from the outer side of the key top64serving as the front of the push button portion5by the light passing through the diffusion plate66.

Furthermore, by canceling the pressure of the key top64of the push button portion5, the resilience of the movable electrode formed by the spring material of the built-in switch2pushes up the bush button30of the built-in switch2and the movable contact point of the movable electrode separates from the fixed contact point to turn off the switch. In this case, the muffling member51and switch operating member48along the push button30are pushed up and moreover, the key top64and operating shaft67are pushed up.

Therefore, the left lever member34L rotates clockwise about its rocking fulcrum P as shown inFIG. 27, the right lever member34N rotates counterclockwise abut its rocking fulcrum as shown inFIG. 27, and the lever folding point Q of the left and right lever members34L and34N lowers to become the state shown in FIG.26.

When normally pushing the key top64of the push button portion5, the lower end of the operating shaft67contacts the elastic stopper member57as shown inFIG. 29to correspond to the pressure of the member57. However, when pushing the key top64of the push button portion5at an excessive pressure, the lower end of the operating shaft67collides with the stopper member57as shown inFIG. 30, the stopper member57deflects, collides with the light guiding plate61at the case1side and is supported by the case1, and the case1is supported by the shock absorbing member73. Therefore, the push button switch S is prevented from being broken due to the pressure.

According to the above embodiment, a contact gap necessary to open or close the contact point of the built-in switch2, that is, the opening distance between contact points for the built-in switch2to be safely turned off is different from the movement stroke of the push button portion5. A movement stroke equal to or more than the opening distance between contact points for a contact point portion to be safely turned off has been necessary for a push button portion (key top) so far. However, because it is possible to adjust the difference between a predetermined stroke of the push button portion5and a stroke (contact point gap) necessary to open or close the contact point of the built-in switch2by selecting a lever ratio between the lever members34L and34N, it is possible to securely operate the built-in switch2by the predetermined movement stroke of the push button portion5.

For example, when making the movement stroke of the push button portion5smaller than the stroke (contact point gap) necessary to open or close the contact point of the built-in switch2so as to securely operate the built-in switch2, it is only necessary to use the lever members34L and34N having lever ratios different each other obtained by changing the distance L1 between a pushing-force acting point “a” located on the connecting shaft35and the rocking fulcrum P and the distance L2 between the rocking fulcrum P and the lever folding point Q as shown in FIG.12.

Thus, because the built-in switch2can be securely operated by making the movement stroke of the push button portion5smaller than the stroke (contact point gap) necessary to open or close the contact point of the built-in switch, it is possible to decrease the thickness of the push button switch S.

Moreover, because the push button portion5is moved in its pushing direction in parallel by the lever link mechanism F, it is possible to operate the lever members34L and34N and securely operate the built-in switch2through the switch operating member31even if pushing the push button portion5in accordance with a deviated pushing way.

Particularly, because the lever link mechanism F has a pair of left and right lever members34L and34N which rock about the rocking fulcrum P and the both lever members34L and34N are connected each other so that they can be bent by the joint members44F and44R at the facing end at which the members34L and34N are faced each other, it is unnecessary to use an elevating link constituted by connecting two links having been generally used each other at their intermediate portions and therefore, it is possible to decrease the thickness of the push button switch S.

Moreover, according to this embodiment described above, the both lever members43L and43N are constituted by bending one wire and have the connecting shaft35and arms38F and38R formed at the both ends of the connecting shaft35, fronts of the arms38F and38R are formed into faced ends, the joint member44F is set to the left (one) lever member34L by inserting the pin portion42F of the arm38F into the pin inserting hole45of the joint member44F and the connecting portion41F into the pin inserting groove46, the joint member44R is set to the right (the other) lever member34N by inserting the pin portion42F of the arm38F of the member34N into the pin inserting hole45of the joint member44R and connecting portion41F into the pin inserting groove46, the pin portion42R of the left lever member34L is inserted into the slide groove47of the joint member44F, and the pin portion42R of the right lever member34N is inserted into the slide groove47of the joint member44R so as to form the lever folding point Q for joint-moving the left and right lever members34L and34N on a line “c” connecting the pins42R serving as lever-side sliding portions of the left and right lever members34L and34N each other. Therefore, by pushing the push button portion5, it is possible to move the push button portion5in its bushing direction in parallel by the lever link mechanism F, joint-move the left and right lever members34L and34N constituting the lever link mechanism F at the lever folding point Q by rocking the members34L and34N about their rocking fulcrums P when the lever link mechanism F is operated by pushing in the push button portion5, and easily exhibit the parallel movement function of the lever link mechanism F.

Furthermore, it is possible to form the lever link mechanism F into a simple and low structure and contribute to decrease of the push button switch S in thickness.

Furthermore, according to the above-described embodiment, because a pair of lever members34L and34N is constituted by a metallic wire, they become tough. Therefore, though a lever member made of a synthetic resin is weak in shock and may be broken, a lever member of this embodiment is strong in shock and it is not broken and thereby, it withstands long-term use of the push button switch S. Moreover, a lever member of this embodiment can be inexpensively fabricated.

Furthermore, according to the above embodiment, the switch operating member48has the switch operating portion49at its intermediate portion and the lever-member hanging portions50L and50N at its both ends, in which the left lever-member hanging portion50L is rotatably set to the connecting shaft35of the left lever member34L, the right lever-member hanging portion50N is rotatably set to the connecting shaft35of the right lever member34N, and the switch operating portion49is faced with the push button30of the built-in switch2. Therefore, the lever link mechanism F is able to hold the switch operating member48and by operating the level link mechanism F, the switch operating member48can securely operate the built-in switch2.

Furthermore, according to this embodiment, the push button portion5contacts the connecting shaft35of the left and right lever members34L and34N, the switch operating member48receives an upheaval force for return in the direction opposite to the pushed direction of the push button portion5to join-move the left and right lever members34L and34N so that they become convex at the lever folding point Q. Moreover, because the switch operating member48pushes up the push button portion5, by pushing the push button portion5, the member48moves the push button portion5in its pushed direction by the lever link mechanism F, rocks the left and right lever members34L and34N constituting the lever link mechanism F about the rocking fulcrum P, joint-moves the left and right lever members34L and34N so that they become convex in the direction opposite to the pushed direction at the lever holding point Q and works so as to push down the switch operating member48. Thereby, it is possible to securely operate the built-in switch2and particularly, form the lever link mechanism F into a low structure and contribute to decrease of the push button switch S in thickness.

Furthermore, according to this embodiment, because the muffling member51is present between the switch operating member48and the push button30of the built-in switch2, when the switch operating member48pushes in the push button30of the built-in switch2through the muffling member51, a pressure for the switch operating member48to push the push button30is added to the pushing force by the member48. However, because the spring force of the muffling member51works in the direction opposite to the pushed direction of the push button30, that is, the spring force of the muffling member51acts so as to cancel the pressure, the collision speed of the movable contact point of the built-in switch2against the fixed contact point decreases, the collision load between the contact points decreases, and it is possible to eliminate a noise of “click” generated when the movable contact point contacts the fixed point.

Furthermore, according to this embodiment, by setting the illuminating portion4for illuminating the front of the push button portion5to the case1so as to cover the switch operating member48, it is possible to realize a low structure and contribute to decrease of a push button switch in thickness.

Furthermore, according to this embodiment, when pushing the key top64at an excessive pressure, an end of the operating shaft67collides with the stopper member57, the stopper member57deflects and collides with the illuminating portion4present at the case1side and supported by the case1, and moreover the case1is supported by the shock absorbing member73. Therefore, it is possible to prevent the push button switch S from being broken due to a pressure.

Furthermore, as shown inFIGS. 31 and 32, it is also allowed to form a spring setting hole86at lower ends of four corners of the operating shaft67, set a return coil spring87to these spring setting holes86, and use spring forces of these return coil springs87to return the push button portion5.

As described above, according to a push button switch of the present invention, by pushing a push button portion, it is possible to move the push button portion in parallel in its pushed direction by a lever link mechanism, rock a lever member constituting the lever link mechanism about a rocking fulcrum when the lever link mechanism operates by pushing in the push button portion, and operate a switch portion by a switch operating member.

A contact gap necessary to open or close the contact point of a switch portion, that is, the opening distance between contact points for the switch portion to be safely turned off is different from the movement stroke of a push button portion. Though a movement stroke equal to or more than the opening distance between contact points for a contact point potion to be safely turned off has been necessary so far for a push button portion (key top), it is possible to securely operate the switch portion by a small movement stroke of the push button portion because the difference between a predetermined movement stroke of the push button portion and a stroke (contact point gap) necessary to open or close the switch portion can be adjusted by selecting a lever ratio of a lever member.

That is, to securely operate a switch portion by making the movement stroke of a push button portion smaller than the stroke (contact point gap) necessary to open or close the contact point of the switch portion, it is only necessary to use lever members having lever ratio different each other.

Thus, because a switch portion can be securely operated by making the movement stroke of the push button portion smaller than the stroke (contact point gap) necessary to open or close the contact point of the switch portion, it is possible to decrease the thickness of a push button switch.

Particularly, because a lever link mechanism has a pair of lever members which rock about a rocking fulcrum and the both lever members are constituted by overlapping each other so that they can be folded and slid at their ends faced each other, it is unnecessary to use an elevating link constituted by slidably connecting two links having been generally used at their intermediate portions and it is possible to decrease the thickness of a push button switch.