Push switch

Abstract

Fixed contacts 11, 12, 13 and 14 are provided on the bottom face 10B of recess 10A in switch housing 10. Two contact-receptors 10C, 10D are disposed at corners so as to confront each other on the bottom face 10B. Outer rim 15B of domed movable contact 15 made of thin metal plate and bowed upwardly is placed on the receptors so that a lower face of top 15A of movable contact 15 faces fixed contacts 11, 12, 13 and 14. Flexible film 16 is fixed so that film 16 covers recess 10A and accommodates domed movable contact 15.

Description

FIELD OF THE INVENTION

The present invention relates to a push switch used in portable electronic devices including a cellular phone, a headphone stereo cassette and the like.

BACKGROUND ART

Recently, portable electronic devices have been downsized and thinned remarkably. Thus, the demand for the push switches used in these portable electronic devices to also be downsized and thinned has been strong.

A conventional push switch is described hereinafter with reference to FIGS. 14 and 15 . FIG. 14 is a front cross sectional view of the conventional push switch. FIG. 15 is a plan view of a switch housing illustrating a fixed contact of the switch shown in FIG. 14 .

The conventional push switch shown in FIGS. 14 and 15 comprises a switch housing 1 shaped as a box and made of insulated resin, a central fixed contact 2 disposed at the center of a bottom face of a recess in switch housing 1 , coupling terminals 2 A, 2 B extending from the central fixed contact 2 to the outside of switch housing 1 , an outside fixed contact 3 disposed on a periphery of the recess of switch housing 1 , coupling terminals 3 A, 3 B extending from the outside fixed contact 3 to the outside of switch housing 1 , a domed movable contact 4 bowed upwardly, made of a thin metallic plate and accommodated in the recess so that its outer rim is placed on outside-fixed-contact 3 of switch housing 1 , and a flexible film 5 covering the recess which accommodates domed-movable contact 4 .

Coupling, terminals 2 A, 2 B, 3 A and 3 B are insert-molded with switch housing 1 and led outside the housing 1 . Film 5 has bonding agent 5 A on its lower face. Film 5 adheres to upper face of the periphery of the recess due to bonding agent 5 A. A small and thin push switch is thus structured.

An operation of the push switch structured above is described hereinafter. First, film 5 is depressed downwardly, then top section 4 A of domed movable contact 4 is bent and elastically deformed. This elastic deformation brings top section 4 A into contact with central fixed contact 2 . Therefore, outside fixed contact 3 becomes electrically connected to central fixed contact 2 via domed movable contact 4 . In other words, the push switch is turned on. When the depressing force is removed, movable contact 4 restores itself to an original place shown in FIG. 14 due to its elastic restoring force (i.e., the push switch is turned off).

However, in the conventional push switch discussed above, coupling terminals 2 A, 2 B are electrically connected to the central fixed contact, and coupling terminal 3 A, 3 B are electrically connected to the outside fixed contact. These four terminals 2 A, 2 B, 3 A and 3 B are led outside switch housing 1 . When the conventional push switch is mounted onto a printed wired board, a wiring for the push switch must be coupled to at least one of terminals 2 A and 2 B. In the same manner, the wiring also must be coupled to at least one of terminals 3 A and 3 B. Thus, the circuit wiring is routed with some restrictions in a design stage. As a result, when a-printed-wiring-circuit including the conventional push switch is designed, a subject electronic device to be designed encounters restrictions of downsizing and thinning.

SUMMARY OF THE INVENTION

The present invention addresses the problem discussed above, and aims to provide a push switch which allows increased flexibility in the design of a printed wiring board. As a result, restrictions in the design of a thin and compact electronic device can be reduced.

To achieve the object, the push switch of the present invention includes at least three fixed contacts disposed electrically independently on a bottom face at a recess of a switch housing shaped as a box and made of insulated resin. Coupling terminals extend from these fixed contacts and are led out externally, and contact-receptors are provided at corners of the bottom face of the recess. A domed movable contact has a center section which is bowed upwardly, and the movable contact is placed on the contact-receptors and accommodated in the recess of the switch housing, and a lid covers the recess and is fixed to the switch housing.

When the push switch structured above is depressed, the domed movable contact is reversed and brought into contact with the plural fixed contacts simultaneously. Therefore, two random coupling terminals led out from the plural fixed contacts can have a switch function. As a result, a push switch, which allows increased flexibility in the design of a printed wiring board and reduces restrictions in the design of a thin and compact electronic device, is obtainable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front cross sectional view of a push switch in accordance with a first exemplary embodiment of the present invention.

FIG. 2 is an exploded perspective view of the push switch shown in FIG. 1 .

FIG. 3 is a plan view of a switch housing illustrating fixed contacts of the push switch shown in FIG. 1 .

FIG. 4 is a perspective view of the switch housing illustrating another shape of the fixed contacts of the push switch shown in FIG. 1 .

FIG. 5 is a front cross sectional view of another form of a domed movable contact of the push switch shown in FIG. 1 .

FIG. 6 is an exploded perspective view of a push switch in accordance with a second exemplary embodiment of the present invention.

FIG. 7 is a plan view of a switch housing illustrating fixed contacts of the push switch shown in FIG. 6 .

FIG. 8 is a plan view illustrating a contact slip of the push switch shown in FIG. 6 in the switch housing.

FIG. 9 is a plan view illustrating another form of the contact slip of the push switch in FIG. 6 housed in the switch housing.

FIG. 10 is a front cross sectional view of a push switch in accordance with a third exemplary embodiment of the present invention.

FIG. 11 is an exploded perspective view of the push switch shown in FIG. 10 .

FIG. 12 is a lateral cross section of a push switch in accordance with a fourth exemplary embodiment of the present invention.

FIG. 13 is an exploded perspective view of the push switch shown in FIG. 12 .

FIG. 14 is a front cross sectional view of a conventional push switch.

FIG. 15 is a plan view of a switch housing illustrating fixed contacts of the conventional push switch shown in FIG. 14 .

DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention are demonstrated hereinafter with reference to the accompanying drawings FIG. 1 through FIG. 13 .

EXEMPLARY EMBODIMENT 1

FIG. 1 is a front cross sectional view of a push switch in accordance with the first exemplary embodiment of the present invention. FIG. 2 is an exploded perspective view of the push switch shown in FIG. 1 . The push switch in accordance with the first exemplary embodiment includes a switch housing 10 open upwardly and made of insulated resin. Four fixed contacts 11 , 12 , 13 and 14 are disposed at a center section on bottom face 10 B of recess 10 A of switch housing 10 . Two contact-receptors 10 C, 10 D form a step and are disposed on bottom face 10 B of switch housing 10 so that the two receptors face each other. Domed movable contact 15 is bowed upwardly, and is made of thin metallic plate and accommodated in the recess 10 A of switch case 10 and placed on contact-receptors 10 C, 10 D. A cover made of flexible film 16 covers recess 10 A of the switch housing.

The four fixed contacts 11 , 12 , 13 and 14 have contact points 11 A, 12 A, 13 A and 14 A whose upper faces protrude. Outer rim 15 B of movable contact 15 is placed on receptors 10 C, 10 D, which form step and are disposed on bottom face 10 B of switch housing 10 so as to face each other. Contact-receptors 10 C, 10 D are formed so as to avoid (be separated from) the four fixed contacts ( 11 , 12 , 13 and 14 ). The lower face of top section 15 A of domed movable contact 15 faces four fixed contacts 11 , 12 , 13 and 14 . Flexible film 16 has bonding agent 16 A on its lower face, and is bonded to an upper face of switch housing 10 due to bonding agent 16 A. From respective fixed contacts 11 , 12 , 13 and 14 , coupling terminals 11 B, 12 B, 13 B and 14 B are led to the outside of switch housing 10 . As shown in FIG. 3 , respective fixed contacts 11 , 12 , 13 and 14 are fixed to bottom face 10 B of switch housing 10 by insert-molding, and they are electrically independent (i.e., not electrically connected). These fixed contacts and coupling terminals are made by punching the same thin metallic plate. The punched fixed contacts and the coupling terminals are insert-molded when the switch housing is molded with insulated resin. As a result, the fixed contacts and the coupling terminals can be made from one material, so that materials and processes are streamlined on the push switch, and the switch housing can be manufactured efficiently.

An operation of the push switch structured as discussed above is demonstrated hereinafter. When flexible film 16 is depressed downwardly, top section 15 A of domed movable contact 15 is elastically deformed. This deformation brings the lower face of top section 15 A into contact with the four contact sections 11 A, 12 A, 13 A and 14 A. When the depression is stopped, movable contact 15 restores itself to its original form by its own restoring force (i.e., the push switch is turned off).

Through the depressing operation, four fixed contacts 11 , 12 , 13 and 14 , electrically independent of each other, are electrically connected to each other simultaneously via domed movable contact 15 , which is made of electrically-conductive metal. When the depressing is stopped, respective fixed contacts 11 , 12 , 13 and 14 are no longer electrically connected to each other simultaneously. As a result, two terminals randomly selected from coupling terminals 11 B, 12 B, 13 B and 14 B extended from each fixed contact 11 , 12 , 13 and 14 function as a switch. In other words, when film 16 is depressed downwardly, the selected two terminals are electrically connected, and when the depressing is stopped, the two selected terminals are not electrically connected.

The push switch used in this first embodiment can have a switch function between the two coupling terminals led out from two fixed contacts randomly selected from the plural fixed contacts. Therefore, an arbitrary combination of the coupling terminals can increase the flexibility in the design of a printed wiring board.

Since respective terminals are independent of each other, another switch can be formed between one terminal and the others. This is another advantage of this embodiment.

The fixed contacts in this embodiment are described together with a protruded contact section of the domed movable contact. However, as shown in FIG. 4 , fixed contacts 21 , 22 , 23 and 24 embossed on bottom face 20 B of recess 20 A of switch housing 20 can be brought into contact with the domed movable contact in a stable manner.

Further as shown in FIG. 5 , domed movable contact 25 can have a protrusion 25 A on its lower face, and the protrusion faces the fixed contacts. This protrusion 25 A allows the domed movable contact to be brought into contact with respective fixed contacts in a stable manner.

The push switch shown in FIGS. 3 , 4 and used in the first embodiment is described with four fixed contacts. When a switch has three fixed contacts, two terminals out of three extended from the respective contacts are randomly selected, and those two terminals can function as a switch. When a switch has five or more fixed contacts, two terminals randomly selected out of the terminals extended from the respective contacts can function as a switch. Therefore, an arbitrary combination of respective terminals can increase the amount of flexibility in the design of a printed wiring board.

EXEMPLARY EMBODIMENT 2

FIG. 6 is an exploded perspective view of a push switch in accordance with the second exemplary embodiment of the present invention. FIG. 7 is a plan view of a switch housing illustrating fixed contacts of the push switch shown in FIG. 6 . The push switch shown in FIGS. 6 and 7 used in the second embodiment includes a switch housing 30 open upwardly, and four fixed contacts 31 , 32 , 33 and 34 are disposed electrically independently on bottom face 30 B of recess 30 A in switch housing 30 . A contact slip 35 approximately shaped as a fork and made of elastic thin metallic plate, is accommodated in recess 30 A. A domed movable contact 36 is bowed upwardly, and is made of elastic thin metallic plate and placed on contact slip 35 . A cover formed of flexible film 37 covers domed movable contact 36 .

Four fixed contacts 31 , 32 , 33 and 34 are disposed electrically independently (i.e., not electrically connected) on bottom face 30 B of the recess and insert-molded. The four contacts have protrudedly processed contact sections 31 A, 32 A, 33 A and 34 A on their upper faces. Two contact-receptors 30 C, 30 D forming a step are disposed on bottom face 30 B so that they face each other. Receptors 30 C and 30 D are formed to avoid (i.e., be separated from) the four fixed contacts 31 , 32 , 33 and 34 . Coupling terminals 31 B, 32 B, 33 B and 34 B extending from respective fixed contacts are led out outside switch housing 30 . Flexible film 37 has bonding agent 37 A on its lower face, and film 37 covers recess 30 A and is fixed to the upper face of housing 30 due to bonding agent 37 A.

As shown in FIG. 7 , three contact sections 32 A, 33 A and 34 A out of four fixed contacts are placed in one side of bottom face 30 B and aligned. The remaining contact section 31 A is located on the other side of the bottom face 30 B opposite the three contact sections.

Contact slip 35 shown in FIG. 8 , a plan view, is accommodated in switch housing 30 . Contact slip 35 includes two supporting sections 35 A and 35 B, both shaped as arcs and extending along both sides of the inner rim of recess 30 A, a center section 35 C including contact section 35 I formed between two supporting sections 35 A and 35 B, an arm 35 E extending from center section 35 C, moderately curved upwardly and having three-sectioned fork 35 D on its end, and contact sections 35 J, 35 K and 35 L downwardly protruding from tips 35 F, 35 G and 35 H extended from three-sectioned fork 35 D.

Two supporting sections 35 A and 35 B are placed above two contact-receptors 30 C and 30 D. Four contact sections 35 I, 35 J, 35 K and 35 L are placed corresponding to contact sections 31 A, 32 A, 33 A and 34 A of fixed contacts 31 , 32 , 33 and 34 . Normally, contact sections 35 J, 35 K and 35 L are spaced a given distance apart from contact sections 32 A, 33 A and 34 A, and face respectively toward each other. On the other hand, contact section 35 I is disposed so that it is always brought into contact with contact section 31 A of fixed contact 31 .

An operation of the push switch structured above and used in the second embodiment is demonstrated hereinafter.

Flexible film 37 is depressed downwardly, then domed movable contact 36 is bent and elastically deformed. This deformation allows top section 36 A to depress three-sectioned fork 35 D of contact section 35 . This depression bends arm 35 E downwardly. This downward bending allows contact sections 35 J, 35 K and 35 L provided on tips 35 F, 35 G and 35 H to be brought into contact with corresponding contact sections 32 A, 33 A and 34 A. Then this contact allows respective fixed contacts 31 , 32 , 33 and 34 , which are electrically independent, to be electrically connected to each other simultaneously via contact slip 35 .

According to the second embodiment, the domed movable contact is elastically deformed, so that the respective contact sections ( 35 F, 35 G and 35 H) of the three-sectioned fork of the arm end are brought into contact with the corresponding contact sections of the fixed contacts. In other words, top section 36 A of the movable contact elastically deformed is brought into contact with the three-sectioned fork 35 D, then fork 35 D moves responsive to-the movement of the movable contact. Then the contact sections ( 35 F, 35 G and 35 H) of the fork's tips move toward the corresponding fixed contacts ( 32 A, 33 A and 34 A) responsive to the movement of the fork. The moving quantity of respective contact sections ( 35 F, 35 G and 35 H) of the fork's tips is greater than that of the three-sectioned fork 35 D.

In the operation discussed above, the area of top section 36 A brought into contact with three-sectioned fork 35 D is smaller than the total area of the plural fixed contacts ( 31 A, 32 A, 33 A and 34 A). However, top section 36 A depresses three-sectioned fork 35 D, so that respective contact sections of the tip of fork 35 D keep contact with corresponding fixed contacts disposed on bottom face 30 B in a stable manner.

The contact sections ( 35 F, 35 G and 35 H) of the fork's tips can be arranged at given intervals. Therefore, the fixed contacts ( 32 A, 33 A and 34 A) are arranged with given insulated spaces on bottom face 30 B, and respective fixed contacts are kept electrically independent of each other. Further, arm 35 E can be extended, so that the characteristics of service life with respect to the repeated depressions of the switch can be improved.

In the push switch in accordance with the first embodiment, domed movable contact 15 is brought into contact directly with the fixed contacts ( 11 A, 12 A, 13 A and 14 A) placed on bottom face 10 B. Therefore, respective contacts are packed closely together, and are thus spaced with narrow intervals. On the other hand, the fixed contacts ( 32 A, 33 A, and 34 A) of the second embodiment can be spaced at wider intervals than those in the first embodiment. As a result, the push switch in accordance with the second embodiment can be used at a relatively higher voltage.

FIG. 9 is a plan view of a switch housing accommodating another form of the contact slip shown in FIG. 6. A push switch shown in FIG. 9 comprises switch housing 40 of which the upper face open. Two contact-receptors 40 C, 40 D forming a step, face each other and are disposed on bottom face 40 B of recess 40 A of switch housing 40 . This structure is the same as described in FIG. 6 .

One contact-receptor 40 C forming a step is selected from the group of contacts 41 , 42 , 43 and 44 , and the selected fixed contact 41 is protrudedly formed. The remaining three contacts 42 , 43 and 44 are disposed at the center of bottom face 40 B. As in the first embodiment, respective fixed contacts 41 , 42 , 43 and 44 are electrically independent and conductive to respective coupling terminals 41 B, 42 B, 43 B and 44 B externally disposed of switch housing 40 .

Outer rim 45 A of contact slip 45 accommodated in recess 40 A of switch housing 40 is approximately shaped as a donut, and a part of the donut is cut off. First end 45 B of the cut-off section is placed on step-like contact-receptor 40 C formed of fixed contact 41 . Arm 45 E extends from second end 45 C toward the center of recess 40 A upwardly in a moderate manner. Arm 45 E couples with three-sectioned-fork 45 D crossing at right angles at the center of recess 40 A. End 45 B and three-sectioned-fork's tips 45 F, 45 G and 45 H have protruded contact sections 451 , 45 J, 45 K and 45 L respectively.

Domed movable contact 46 and flexible film 47 have the same structure as described in FIG. 6 and FIG. 7 . The push switch structured as shown in FIG. 9 works the same as that described in FIG. 6 and FIG. 7 . The push switch shown in FIG. 9 forms a switch by combining two random coupling terminals out of four extended from respective fixed electrically independent contacts. Further, these four terminals can be simultaneously turned on by one depressing. This action is the same as what has been done in the first embodiment.

According to the push-switch shown in FIG. 9 , it is the three-sectioned fork of the contact slip that is deformed by depressing due to the deformation of the domed movable contact. A length between the contact receptor and the three sectioned fork can be longer than the bent portion of the contact slip described in FIG. 6 and FIG. 7 . This structure allows the push switch shown in FIG. 9 to have an extended service life with respect to repeated depressions.

EXEMPLARY EMBODIMENT 3

FIG. 10 is a front cross sectional view of a push switch in accordance with the third exemplary embodiment of the present invention. FIG. 11 is an exploded perspective view of the push switch shown in FIG. 10 .

The opening of switch housing 50 of the third embodiment forms a step, i.e., recess 50 A and recess 50 E. Recess 50 A (the opening of the first step) has the same structure as recess 30 A of switch housing 30 shown in FIGS. 6 and 7 of the second embodiment. Recess 50 A has a round shape and has four fixed contacts 51 , 52 , 53 and 54 electrically independent (i.e., not electrically connected) on bottom face 50 B. Respective fixed contacts 51 , 52 , 53 and 54 have plural protruded contact sections 51 A, 52 A, 53 A and 54 A. Two contact-receptors 50 C and 50 D are provided at nooks on bottom face 50 B. Recess 50 A accommodates contact slip 35 and domed movable contact 36 in the same manner as in the second embodiment. Flexible film 55 having bonding agent 55 A on its lower face is rigidly disposed on the upper face of the opening of the first step. Push-button 56 made of insulated resin is placed on recess 50 E-an opening of the second step. Push-button 56 comprises flange 56 B and operating section 56 C having an upper section smaller than flange 56 B. Flange 56 B has protrusion 56 A which depresses top 36 A of domed movable contact 36 .

Cover plate 57 is made of thin metal plate, and the metal is a rigid material such as stainless steel and has a hole 57 A through which operating section 56 C extends at the center. The cover plate 57 is mounted to switch housing 50 . Cover plate 57 is provided so that it covers the entire opening of switch housing 50 . As a result, push-button 56 is held ready to be depressed.

An operation of the push switch structured as discussed above is demonstrated hereinafter. First, push-button 56 is depressed downwardly so that protrusion 56 A on the lower face pushes down top 36 A of domed movable contact 36 , so that contact 36 is deformed. When the deformed amount exceeds a given (predetermined) amount, domed movable contact 36 elastically deforms itself gradually and depresses down the three-sectioned fork 35 D of arm 35 E of contact slip 35 downwardly. This depression allows three contact sections 35 J, 35 K and 35 L provided at tips 35 F, 35 G and 35 H of fork 35 D to contact corresponding contact sections 52 A 53 A and 54 A of fixed contacts 52 , 53 and 54 provided on bottom face 50 B of switch housing 50 . This contact allows respective fixed contacts 5 l, 52 , 53 and 54 , which are electrically independent, to be simultaneously electrically connected to each other. This conductive operation is the same as that in the second embodiment.

According to the third embodiment, even if the push-button is depressed out of the operating center axis, the domed movable contact is depressed at a given spot due to the protrusion provided on the lower face of the push-button. Therefore, the push switch of the third embodiment advantageously has a stable operation tactile and stable contact.

EXEMPLARY EMBODIMENT 4

FIG. 12 is a lateral cross section of a push switch in accordance with the fourth exemplary embodiment of the present invention. FIG. 13 is an exploded perspective view of the push switch shown in FIG. 12 .

The opening of switch housing 60 of the fourth embodiment forms a step, i.e., recess 60 A and recess 60 E. Recess 60 A (the opening of the first step) has the same structure as recess 50 A of switch housing 50 shown in FIGS. 10 and 11 of the third embodiment. Recess 60 A has a round shape and has four fixed electrically independent contacts 61 , 62 , 63 and 64 on bottom face 60 B. Upper faces of respective contacts 61 , 62 , 63 and 64 have plural protruded contact sections 61 A, 62 A, 63 A and 64 A. Two contact-receptors 60 C and 60 D are provided at nooks on bottom face 60 B. Recess 60 A accommodates contact slip 35 and domed movable contact 36 , as in the third embodiment. Flexible film 55 having bonding agent 55 A on its lower face is rigidly disposed on the upper face of the switch housing 60 .

The first step of this fourth embodiment has the same structure as that of the third embodiment. Opening 60 E of the second step shown in FIG. 13 is formed by four side-walls 60 F and 60 G shaped as “L” side-walls surrounding opening 60 E. The four “L” shaped side-walls are formed on the upper face of first opening 60 A, and push-button 65 made of insulated resin is provided in opening 60 E of the second step. Push-button 65 is depressed in a lateral direction. Push-button 65 includes an operating section 65 A to be depressed, tongue 65 C extending from the center of face 65 B opposite to the face of operating section 65 A depressed toward the center of switch housing 60 , and frame 65 D surrounding tongue 65 C.

Push-button 65 is placed such that operating section 65 A protrudes between two “L” shaped side-walls forming opening 60 E of the second step. Further, frame 65 D of push-button 65 is arranged such that the frame slides with the inside of side-wall 60 G of the “L” shaped side-wall.

Cover plate 66 is mounted to switch housing 60 so that plate 66 covers opening 60 E of the second step where push-button 65 is placed. Cover plate 66 is made of thin metal plate having rigidity, such as stainless steel, and has a “V” shaped wedge 66 A extending downwardly at the center. The slanted face of the wedge 66 A is brought into contact with the tip of tongue 65 C of push-button 65 .

Next, an operation of the push switch structure discussed above is demonstrated hereinafter. First, operating section 65 A of push-button 65 is depressed laterally, then frame 65 D moves horizontally guided by side-wall 60 G of switch housing 60 . This movement allows the tip of tongue 65 C of push-button 65 to be bent downwardly along the slanted face of wedge 66 A of cover plate 66 . This downward bending forces the tip of tongue 65 C to push the top 36 A of domed movable contact 36 just under flexible film 55 .

Then this depressing force elastically deforms domed movable contact 36 , and the lower face of top 36 A of the contact depresses three-sectioned fork 35 D of contact slip 35 . Three contact sections 35 J, 35 K and 35 L provided at the tips of fork 35 D are brought into contact with corresponding contact sections 62 A, 63 A and 64 A of the fixed contacts. These contacts allow respective fixed electrically independent contacts 62 , 63 and 64 to be simultaneously electrically connected to each other. As a result, push switch 60 is turned on.

When the depressing force on operating section 65 A of push-button 65 is removed, the elastic restoring force of domed movable contact 36 works. Therefore, the resultant of two restoring forces-elastic restoring force of movable contact 36 and restoring force of bending tongue 65 C-works. As a result, tongue 65 C returns to its original position along the slanted face of “V” shaped wedge 66 A of cover plate 66 , and domed movable contact 36 is restored to its original condition. Push-button 65 is pressed back to its original place, i.e., the position before it is depressed. Thus the switch is turned off.

According to the embodiments previously described, in addition to the advantages of the second and third embodiments, a simply structured and thin push switch can be obtained by making an operating direction parallel to the plane to which the push switch is mounted.

The “V” shaped wedge disposed at the center of the cover plate may only form a slant toward the switch center, and its shape can be formed by cutting, bending or combining other parts.

In the third and fourth embodiments, a flexible film is used in the description. However, in the push-button, the flexible film can be omitted, so that the number of materials used for the switch can be reduced.

In the second through the fourth embodiments, protruded contact sections provided on the upper faces of four fixed contacts are used in the description. However, recessed contact sections having a narrower width than that of the protruded contact sections can be used. In this case, multi-contacts are prepared thanks to the combination of protrusions and recesses. As a result, stable contact can be expected.

Industrial Applicability

At least three fixed electrically independent contacts are prepared, and two random coupling terminals can have a switch function. Therefore, the push switch of the present invention provides great flexibility to engineers for designing a printed wiring board, and reduces restrictions for designing a compact and thin electronic device.

Claims

1. A push switch comprising:a switch housing formed of insulating resin and having a recess; at least four fixed contacts arranged on a bottom face of said recess so as to be electrically independent of each other; a plurality of electrically independent coupling terminals, each of said coupling terminals being electrically connected to a respective one of said fixed contacts and extending outside of said switch housing; a pair of contact-receptors formed on said bottom face of said recess so that each contact-receptor forms a step on said bottom face, and said contact-receptors being arranged so as to be separated from said fixed contacts; a domed movable contact formed of elastic metal sheet, said domed movable contact being arranged in said recess such that a center of said movable contact protrudes upwardly; a flexible cover rigidly mounted to said switch housing so as to cover said recess; and a contact slip arranged between said at least four fixed contacts and said domed movable contact, said contact slip being formed of elastic metal sheet and having a plurality of contact sections corresponding to said at least four fixed contacts; wherein said contact slip and.said domed movable contact are arranged such that: an outer rim of said contract slip is supported on said contact-receptors; an outer rim of said domed movable contact is supported on said contact slip; one of said contact sections of said contact slip permanently contacts a respective one of said fixed contacts, and a remaining group of said contact sections is operable to move between a non-contact position, whereat said remaining group of said contact sections do not electrically contact a remaining group of fixed contacts, and a contact position, whereat said remaining group of said contact sections electrically contact a remaining group of fixed contacts; and said domed movable contact is operable to push said remaining group of said contact sections from said non-contact position to said contact position so as to simultaneously electrically couple said remaining group of said contact sections and said remaining group of fixed contacts when said flexible cover is pushed against said domed movable contact.

2. The push switch of claim 1, wherein said fixed contacts protrude from said bottom face of said recess of said switch housing.

3. The push switch of claim 1, wherein each of said contact sections of said contact slip has a protrusion extending toward said bottom face of said recess, said contact sections being arranged so that each of said contact sections corresponds to a respective one of said fixed contacts.

4. The push switch of claim 1, wherein said domed movable contact has a protrusion extending toward said bottom face of said recess such that when said domed movable contact is pushed, said protrusion is brought into contact with said contact slip.

5. The push switch of claim 1, wherein each of said fixed contacts is integrally formed with a respective one of said coupling terminals from a metal sheet, and each of said fixed contacts and said coupling terminals is insert-molded with insulating resin to form said switch housing.

6. The push switch of claim 1, further comprising:a push-button having an inner protrusion and being arranged on said flexible cover such that said inner protrusion presses against said flexible cover when said push-button is pushed, said flexible cover comprising a first cover; and a rigid second cover mounted to said switch housing and having a hole, said push-button having an outer protrusion and being arranged such that said outer protrusion is operable to move through said hole of said second cover.

7. The push switch of claim 6, wherein said fixed contacts protrude from said bottom face of said recess of said switch housing.

8. The push switch of claim 6, wherein each of said contact sections of said contact slip has a protrusion extending toward said bottom face of said recess, said contact sections being arranged so that each of said contact sections corresponds to a respective one of said fixed contacts.

9. The push switch of claim 6, wherein said domed movable contact has a protrusion extending toward said bottom face of said recess such that when said domed movable contact is pushed, said protrusion of said domed movable contact is brought into contact with said contact slip.

10. The push switch of claim 6, wherein each of said fixed contacts is integrally formed with a respective one of said coupling terminals from a metal sheet, and each of said fixed contacts and said coupling terminals is insert-molded with insulating resin to form said switch housing.

11. The push switch of claim 1, wherein said flexible cover comprises a first cover, said push switch further comprising:a second cover formed of insulating resin, having a lateral recess on a side thereof, and having a bent section arranged in said lateral recess, said lateral recess having an opening; and a push-button for depressing said first cover, said push-button being mounted through said opening in said lateral recess of said second cover, and being operable to move through said opening, said bent section being arranged so as to guide a tip of said push-button downward when said push-button is pushed laterally such that said tip contacts said bent section.

12. The push switch of claim 11, wherein said fixed contacts protrude from said bottom face of said recess of said switch housing.

13. The push switch of claim 11, wherein each of said contact sections of said contact slip has a protrusion extending toward said bottom face of said recess of said switch housing, said contact sections being arranged so that each of said contact sections corresponds to a respective one of said fixed contacts.

14. The push switch of claim 11, wherein said domed movable contact has a protrusion extending toward said bottom face of said recess of said switch housing such that when said domed movable contact is pushed, said protrusion is brought into contact with said contact slip.

15. The push switch of claim 11, wherein each of said fixed contacts is integrally formed with a respective one of said coupling terminals from a metal sheet, and each of said fixed contact and said coupling terminals is insert-molded with insulating resin to form said switch housing.