US3899648A - Nodally operated push-button switch - Google Patents

Abstract

A snap-action operable push-button switch has a metal contact of rectangular shape having a pair of rectangular holes at both sides of a central stripe integrally formed therewith, the central stripe being bent toward one side thereof and the metal contact also having a pair of rectangular resilient contact pieces integrally extended therefrom in a size smaller than the size of the rectangular holes.

Description

United States Patent Murata Aug. 12, 1975 [54] NODALLY OPERATED PUSH-BUTTON 3,286,045 1 1/1966 Clark, Sr. et a1 200/5 R SWITCH 3,707,609 l2/l972 Dapot et al. t t. 200/159 B 3,749,859 7/1973 Webb et al 200/5 R [75] Inventor; Taneo Murata, Tokyo, Japan 3,749,872 7/1973 Foster 200/159 A [73] Assignee: Alps Electric Co., Ltd., Tokyo,

Japan Primary ExaminerDavid Smith, Jr. [22] Fued;Man 3 19 Attorney, Agent, or Firm-Guy W. Shoup Appl. No.: 450,865

Foreign Application Priority Data Mar. 16, 1973 Japan 48-30685 U.S. Cl. 200/5 R; 200/5 A; 200/67 DB; 200/159 B Int. Cl HOlh 5/30; HOlh 13/64 Field of Search 200/67 DB, 159 A, 159 B, 200/5 R, 5 A, 67 DA; 174/100 P References CitedUNITED STATES PATENTS 2/1917 Landis 200/67 DB [57] ABSTRACT A snap-action operable push-button switch has a metal contact of rectangular shape having a pair of rectangular holes at both sides of a central stripe integrally formed therewith, the central stripe being bent toward one side thereof and the metal contact also having a pair of rectangular resilient contact pieces integrally extended therefrom in a size smaller than the size of the rectangular holes.

4 Claims, 14 Drawing Figures PAIENTEU AUG 1 2197s SPEET F/G.6A

NODALLY OPERATED PUSH-BUTTON SWITCH BACKGROUND OF THE INVENTION This invention relates to a snap-action (nodally) operable push-button switch used for terminal equipment of electronic device.

It is an objective of the present invention to provide a snap-action operable push-button switch having improved electric characteristics; improved contacting sensitivity, and permitting rapid assembly for high productivity of the siwtch.

It is another objective of the present invention to provide a snap-action operable push-button switch which makes point contact with stationary contacts on a printed circuit substrate and may also positively separate therefrom.

It is a further objective of the present invention to provide a snap-action operable push-button switch which may make contact softly and may also provide sufficient play for knob (push-button) movement.

It is still another objective of the present invention to provide a snap-action operable push-button switch which may simplify the assembling process, reduce the number of wiring parts, and to simplify the wiring process so as to economically assemble small electronic computers such as desk or hand electronic calculators.

It is still another objective of the present invention to provide an operable push-button switch which is advantageous for producing the push-buttons in relatively small numbers and with various types of buttons.

SUMMARY OF THE INVENTION According to the present invention, the operable push-button switch, as one aspect, comprises a plurality of operating units mounted in a frame. Each unit has a sliding lever (not a pivoting lever), a flexible conductive contacting plate with resilient contact pieces, an insulating plate, a coil spring, and a case for enclosing the aforesaid parts to form a multi-key push-button assembly. The contacting plate includes a bent potion (a center strip) formed at the center and bent reversely upon depression and also including resilient contact pieces formed integrally with the bent portion thereby providing a snap action or toggle like (nodal) operation.

These and other objects, features, and advantages of the push-button switch according to the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. IA is a top plane view of the assembly of the snap-action push-button switch of the invention;

FIG. 1B is an enlarged sectional view of the switch taken along the line IB-IB in FIG. 1A.

FIG. 2 is a perspective exploded view of the essential parts of the switch of the invention;

FIG. 3A is a perspective view, partly broken away, of the back of the frame;

FIG. 3B is a perspective view of the back of the case of the switch, partly cut out;

FIG. 3C is a perspective view of the back of the lever, partly cut out of the switch;

FIG. 4 is a side sectional view of the operating unit of the switch of the present invention;

FIG. 5 is an enlarged side sectional view, in the engaged state, of the knob and the lever of the switch of the present invention;

FIGS. 6A and 6B are enlarged perspective views of the flexible contacting plate, in two steps of its manufacture;

FIGS. 7A to 7C are explanatory views of the operation of the flexible contacting plate which deforms at the central stripe thereof upon depression. Wherein FIG. 7A shows the state of the contacting plate before it has been deformed, FIG. 7B shows the state of the contacting plate deforming upon the switch is closed, and FIG. 7C shows the state of the contacting plate mostly deformed; and

FIG. 8 is a side sectional view of the essential part of another embodiment of the switch using a rubber resilient spring instead of the coil spring of the prior embodiment.

Referring now to the drawings, numeral 1 indicates knobs (push-buttons), 2 a frame and 3 an operating unit. Theoperating unit 3 includes a case 4, asliding lever 5, acoil spring 6, a flexibleconductive contacting plate 7, and aninsulating plate 8.Numeral 9 is a printed circuit substrate, and 10 are screws for mounting the printedcircuit substrate 9 to theframe 2.

The snap-action nodally operable push-button of the present invention comprises oneframe 2, one printed circuit substrate, and plurality of operating units 3 (composed as above) and a plurality of knobs to form a multi-key push-button assembly.

The knobs (push-buttons) l are made of synthetic plastic resin, and, as shown in FIG. 5, have an integralcylindrical mounting shaft 11 engaged into ahole 24 of thelever 5 at the lower center thereof. Eachshaft 11 hasintegral projections 12, 12 which oppositely project from both sides of the end of theshaft 11 so that the knob l and thelever 5 are held together. Theroot portion 13 of theshaft 11 is tapered.

As shown in FIG. 2, theframe 2 is made of synthetic plastic resin, and has pluralrectangular holes 14 aligned in a manner crossing at right angles for slidably engaging thelevers 5. Theframe 2 also has corresponding rectangular holes 15 (see FIG. 3A) formed stepwise to theholes 14 on the back of theframe 2 for engaging the rectangular cases 4. Each of the cases 4 (see FIG. 4) includes a small-sizedrectangular portion 18 and large-sizedrectangular portion 19. Theframe 2 has a plurality ofthread holes 17 to receive thescrews 10 for mounting the printed circuit to theframe 2, at its peripheral edge and intermediate portion.

The cases 4 of theoperating units 3 are made of synthetic plastic resin. Each case 4 has a small-sized hollowrectangular portion 18 and large-sized hollowrectangular portion 19 integrally formed therewith, andstep 16 formed between therectangular portions 18 and 19. As shown in FIG. 4, thelever 5 is slidably engaged with the inner wall of the small-sized hollowrectangular portion 18. The outer walls of the small-sized and large-sized hollowrectangular portions 18 and 19 are engaged with theholes 15 of theframe 2, respectively.

As shown in FIG. 38 aseat 20 is formed at the lower edge of the large-sized hollowrectangular portion 19 for mounting themovable contacting plate 7 to theinsulating plate 8.Projections 21 are provided at the respective comers of theseat 20 for fixing themovable contacting plate 7 and theinsulating plate 8.Legs 22 are projected at the opposite surfaces of the large-sized hollowrectangular portions 19 for securing the case 4 to the printedcircuit substrate 9, andclaws 23 are integrally projected from the end of thelegs 22, respectively outwardly. Thelegs 22 are resilient, and when thelegs 22 are inserted into therectangular holes 36 formed at the printedcircuit substrate 9 under pres sure, theclaws 23 of thelegs 22 are engaged with the edges of therectangular holes 36 so that the cases 4 are secured to the printedcircuit substrate 9.

As shown in FIG. 3C, the sliding lever is made of synthetic plastic resin and has ahole 24 formed at its upper central portion thereof for engaging theshaft 11 of the knob 1 and theprojections 12.Lever 5 has ahole 25 for holdingcoil spring 6, thehole 25 being of a larger diameter than thehole 24 at the lower portion thereof, and astep 26 being formed between thehole 24 and 25.Stoppers 27 are formed at the lower portion of thelever 5 for preventing thelever 5, after having been inserted into the case 4, from being discharged out. Thestoppers 27 are in contact with thestep 16 of the case 4. Thecoil spring 6 is inserted into thehole 25 of thelever 5 in a manner that one end thereof is engaged with thestep 26 and the other end thereof is contacted with the center of theniovable contacting plate 7 to urge the movable contactingplate 7 and also to return thelever 5. Thelever 5 slides within an opening and is not a pivoting lever.

The flexible conductive contactingplate 7 is, for example, made of phosphorus bronze thin metal plate having electroconductivity and resiliency. Theplate 7 is punched, in the shape as shown in FIG. 6A, in such a manner that a pair of rectangular holes are formed at both sides ofcentral stripe 28. Thestripe 28 is integrally formed with the plate and a pair of rectangular resilient contact pieces are integrally extended from the vicinity of the center of thestripe 28 in a size, and a shape, smaller than the size of the holes. Both side edges 29 of theplate 7 are parallel with thecentral stripe 28 and are drawn (or formed with any alternative process) into a bump so as to shorten the side edges compared to thecentral stripe 28 as shown in FIG. 6B. Thecentral stripe 28 is bent with the result that theresilient contact pieces 30 extend from thecentral stripe 28. The contact pieces change direction relative to the curve of thecentral stripe 28, Le. they are tangential to the curve. The contact points 31, provided at the ends of theresilient contact pieces 30 are bent to the other side, (downwardly as seen in FIG. 6B). When the center of the bent portion ofcentral stripe 28 is depressed, the bent portion is reversely bent (see FIG. 7B) and when the depression is released, the bent portion returns to the original bent state by the resiliency of thecenter stripe 28. There are providedholes 32 at the respective four corners of the movable contactingplate 7 for engaging (fitting upon) with theprojections 21 of the case 4.

The insulatingplate 8 is made of synthetic plastic resin film, and is sized to meet the size of theseat 20 of the case 4. There are providedholes 33 at the respective comers of the rectangular insulatingplate 8 for engaging with theprojections 21 of the case 4. There are also formedrectangular holes 34 in the insulatingplate 8 for inserting the free ends of theresilient contact pieces 30, respectively. Therectangular holes 34 also enable the contact points 31 (at the ends of the resilient contact pieces 30) to make contact with thestationary contacts 35 of the printedcircuit substrate 9. The insulatingplate 8 insulates (other than its holes 34) the movable contactingplate 7 from the printedcircuit substrate 9.

The desired circuit is formed on the printedcircuit substrate 9. The pluralstationary contacts 35 are to be contacted with the contact points 31 of theresilient contact pieces 30. The printedcircuit substrate 9 also has plural pairs ofrectangular holes 36 formed therethrough for inserting thelegs 22, which mount the cases 4. Since the oblique surfaces of theclaws 23 are contacted with the edges of therectangular holes 36, when thelegs 22 of the cases 4 are inserted into therectangular holes 36 and the cases 4 strongly depressed, thelegs 22 are bent inside so that the ends of theclaws 23 pass through the rectangular holes 36. Simultaneously the bent portions of thelegs 22 are returned to their original states by their resiliency with the result that theclaws 23 are engaged with the edges of therectangular holes 36 so that the cases 4 are secured to the printedcircuit substrate 9. There are also providedplural holes 37 at the printedcircuit substrate 9 for inserting thescrews 10. The mounting of the printedcircuit substrate 9 to theframe 2 may be made by alternative means instead of thescrews 10.

Assemblying of the snap-action nodally operable push-button switch of the present invention will now be described.

The slidinglever 5 is inserted into the small-sized hollowrectangular portion 18 of the case 4, thecoil spring 6 is then inserted into thehole 25 of thelever 5, the bent portion of the movable contactingplate 7 is placed at the side of thecoil spring 6 so that theholes 32 of the four corners are engaged with theprojections 21 of the four corners of the case 4, the movable contactingplate 7 is mounted to the case 4, theholes 33 of the four corners of the insulatingplate 8 are engaged with theprojections 21 of the four corners of the case 4 in the state that therectangular holes 34 of the insulatingplate 8 coincide with thestationary contacts 35 of the printedcircuit substrate 9, and the insulatingplate 8 is mounted to the case, then theprojections 21 of the case 4 are punched, and then the movable contactingplate 7 and the insulatingplate 8 are fixed to the case 4, and thus theoperating unit 3 is assembled.

As shown in FIG. 4, the assembledoperating unit 3 is so constructed that the central stripe of the movable contactingplate 7 is bent upwardly as shown in the drawing, so as to push upwardly thecoil spring 6. Thecoil spring 6 urges upwardly thelever 5 with the result that thestoppers 27 of thelever 5 are contacted with thestep 16 of the case 4 so as to prevent thelever 5 from being discharged out. The desired number of the operatingunits 3 are previously assembled, and then thelegs 22 of the case 4 of theoperating unit 3 are press-fitted within a pair ofrectangular holes 35 of the printedcircuit substrate 9, and then theclaws 23 of thelegs 22 are engaged with the edges of the pair ofrectangular holes 36 so that the operatingunits 3 are secured to the printed circuit substrate. Thus, a desired number ofoperating units 3 are mounted to the printedcircuit substrate 9.

Then, the cases 4 of therespective operating units 3 are engaged with the holes l5 of theframe 2, i.e., theframe 2 is located onplural operating units 3, and then screws 10 are inserted intoplural holes 37 of the printed circuit substrate and are screwed with the thread holes 17 of theframe 2 and are then tightened so as to secure the printedcircuit substrate 9 to theframe 2, and the operatingunits 3 are fixed between the printedcircuit substrate 9 and theframe 2. Then, the mountingshafts 11 of the respective knobs 1 are engaged so as to press-fit theprojections 12 to theholes 24 of thelevers 5 presented at theholes 14 of theframe 2 thereon, and then the knobs 1 are turned at 90 so as not to be discharged out from thelever 5 to complete the assembling.

Then, the operation of the nodally operable pushbutton switch of the present invention will now be described.

Thecentral stripe 28 of the movable contactingplate 7 of the push-button switch, assembled but not yet operated, is bent upwardly as in FIG. 7A. At the side of thelever 5, the free ends of theresilient contact pieces 30 are also directed upwardly. The contact points 31 (at the free ends of the resilient contact pieces 30) are separated from thestationary contacts 35 of the printedcircuit substrate 9, and the push-button switch is in its open state. The bent portion of thecentral stripe 28 of the movable contactingplate 7 pushes the lever S and the knobs 1 upwardly, and thestoppers 27 of the lever S are contacted with thestep 16 of the case 4 to hold the lever S in the stopped state.

When the knob 1 is now depressed, thelever 5 compresses thecoil spring 6, whichspring 6 urges the center of thecentral stripe 28 of the movable contactingplate 7. When thecoil spring 6 is compressed to a certain degree, thecentral stripe 28 is also started to be in flexure, and when thecoil spring 6 is further compressed, thecentral stripe 28 cannot endure the depression so that thecentral stripe 28 is abruptly deformed from the state shown in FIG. 7A to that shown in FIG. 713, with the result that the center of thecentral stripe 28 is reversely bent and the inclined direction of theresilient contact pieces 30 are also abruptly changed so that the contact points 31 are abruptly moved downwardly. The contact points 31 are then positively contacted with thestationary contacts 35 of the printedcircuit substrate 9, and then the circuit is closed. The reversing speed of thecentral stripe 28 of the movable contactingplate 7 when reversely bent is faster than the moving speed of the knob 1 up to that time, (a type of toggle action), and the depression to the knob 1 when reversely bent is abruptly reduced, and accordingly the knob l is nodally moved. When the knob l is further depressed even after the circuit is closed, thecoil spring 6 and thecentral stripe 28 of the movable contactingplate 7 are further compressed so that thecentral stripe 28 of the movable contactingplate 7 becomes as shown in FIG. 7C so as to provide sufficient moving allowance of the knob 1. When the depression is released, thecentral stripe 28 of the movable contactingplate 7 urges thecoil spring 6, by its own resiliency, and returns to its original bent state and thecoil spring 6 is also returned to its original state by its resiliency thereof so as to simultaneously return the knob 1.

A resilient member such asspring 38, see FIG. 8, formed of rubber of rubber resilient material as shown in FIG. 8 may be used instead of thecoil spring 6.

The following advantages and effects can be provided by the nodally operable push-button switch of the invention:

It should be understood from the foregoing description that since the nodally operable push-button switch of the present invention comprises the movable contactingplate 7 which is shortened at theedges 29 by drawing so that the opening and closing of the switch is nodally conducted and the switch also comprises spherical contact points 31 at the free end of theresilient contact pieces 30 so as to effect point-contact with thestationary contacts 35 on the printedcircuit substrate 9, positive separation of thepoint contacts 35 can be attained so as to improve the electric characteristics.

It should also be understood that since thecoil spring 6, such as resilient material made of rubber or rubber substance, is disposed between the movable contactingplate 7 and thelever 5 in the switch of the invention, the contacting sensitivity of the contacts is soft and the play of the moving degree of the knob 1 may be sufficiently provided so as to improve the contacting sensitivity.

It should also be understood that since the nodally operable push-button switch of the invention comprises wiring portion of operational circuit, stationary contacts and circuit portion of push-button switch formed on one printed circuit substrate and said operational circuit mounted at the wiring portion of the operational circuit, operating units mounted at the pushbutton switch portion as one-touch operation type sim ply assembled compared with the conventional desk type electronic computer which as separate pushbutton portion and operational circuit portion and lead wires for connection the former to the latter, the assembling process, wiring parts and the number of wiring processes can be reduced so as to assemble the desk type electronic computer less expensively.

It should also be understood that since the knobs 1 andframe 2 andoperation units 3 are combined with the printedcircuit substrate 9 in the switch of the present invention, so that when push-button switches for different key numbers are produced, only the designs of printed circuit substrate and theframe 2 may be changed and when different design of the knob l is necessary, only the knob l of different design may be formed and may be mounted thereto, it is advantageous for producing small numbers and various types of pushbutton switches.

What is claimed is:

l. A nodally operable push-button switch comprising a case, and a flexible conducting metal plate, said plate having a normally curved central stripe and a pair of rectangular holes at both sides of said central stripe integrally formed therewith and also having a pair of resilient contact pieces integrally extended therefrom smaller than the size of the holes, and opposite side edges of said metal plate being drawn so that they are shorter than the said central stripe.

2. A nodally operable push-button switch as set forth in claim 1, further comprising a lever mounted slidably into said case, and a resilient means disposed between the said curved central stripe and said lever.

3. A nodally operable push-button switch as set forth inclaim 2, further comprising a printed circuit substrate having stationary contacts, and a frame. said case having legs with claws integrally projected therefrom said claws being engaged with holes provided in said printed circuit substrate, said lever being slidably inserted into said case, and an insulating plate provided on said printed circuit substrate and having a pair of rectangular holes formed therethrough for contacting said stationary contacts.

4. A nodally operable push-button switch as set forth in claim 1, further comprising a printed circuit substrate having a plurality of stationary contacts, a frame having a plurality of holes aligned in a manner crossing at right angles with each other, a plurality of cases each having legs, each of said legs having claw portion for engaging with said printed circuit substrate, a lever slidably inserted into said case, a movable contacting plate disposed at the bottom of said case, said contacting plate having a central strip with a bent portion and having a pair of rectangular holes at both sides of central stripe integrally formed therewith and also having a pair of rectangular resilient contact pieces integrally extended therefrom which are smaller than the size of the holes, and opposite side edges of said metal plate being drawn to be shorter than the central stripe of said metal plate, an insulating plate having a pair of rectangular holes for contacting the stationary contacts provided on said printed circuit substrate, said lever having a spring hole, a resilient material inserted between the spring holes of said lever and the bent portion of said movable contacting plate to form an operating unit, a plurality of said operating units mounted to said printed circuit substrate and said frame, and a plurality of knobs with mounting shafts engaged with the holes of said levers, said levers being slidably inserted into the holes of said frame.

Claims (4)

1. A nodally operable push-button switch comprising a case, and a flexible conducting metal plate, said plate having a normally curved central stripe and a pair of rectangular holes at both sides of said central stripe integrally formed therewith and also having a pair of resilient contact pieces integrally extended therefrom smaller than the size of the holes, and opposite side edges of said metal plate being drawn so that they are shorter than the said central stripe.

2. A nodally operable push-button switch as set forth in claim 1, further comprising a lever mounted slidably into said case, and a resilient means disposed between the said curved central stripe and said lever.

3. A nodally operable push-button switch as set forth in claim 2, further comprising a printed circuit substrate having stationary contacts, and a frame, said case having legs with claws integrally projected therefrom said claws being engaged with holes provided in said printed circuit substrate, said lever being slidably inserted into said case, and an insulating plate provided on said printed circuit substrate and having a pair of rectangular holes formed therethrough for contacting said stationary contacts.

4. A nodally operable push-button switch as set forth in claim 1, further comprising a printed circuit substrate having a plurality of stationary contacts, a frame having a plurality of holes aligned in a manner crossing at right angles with each other, a plurality of cases each having legs, each of said legs having claw portion for engaging with said printed circuit substrate, a lever slidably inserted into said case, a movable contacting plate disposed at the bottom of said case, said contacting plate having a central strip with a bent portion and having a pair of rectangular holes at both sides of central stripe integrally formed therewith and also having a pair of rectangular resilient contact pieces integrally extended therefrom which are smaller than the size of the holes, and opposite side edges of said metal plate being drawn to be shorter than the central stripe of said metal plate, an insulating plate having a pair of rectangular holes for contacting the stationary contacts provided on said printed circuit substrate, said lever having a spring hole, a resilient material inserted between the spring holes of said lever and the bent portion of said movable contacting plate to form an operating unit, a plurality of said operating units mounted to said printed circuit substrate and said frame, and a plurality of knobs with mounting shafts engaged with the holes of said levers, said levers being slidably inserted into the holes of said frame.

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