US3854018A - Multiple circuit selector switch assembly having movable contact means adapted to retain itself in closed circuit position - Google Patents

Abstract

A switch assembly has an apertured grate superimposed upon a contact board on which a plurality of independent electrical contacts are located. The apertures in the grate are respectively associated with the contacts to expose the contacts through the grate. A cross-curved elongated contact strip is operatively connected to the grate on the side thereof opposite the contacts in a predetermined position and configuration such that the strip is flexed between its points of connection to the grate in order to form a single projection which extends into one of the apertures and engages the contact associated therewith. The cross-curved contact strip flattens at the projection within the aperture because of the flexing of the strip, and thus holds the strip in that aperture until the strip is urged through another aperture in the grate, either manually or by a pushbutton or the like, thereby causing the projection in the strip to occur at the other aperture and relieving the projection at the aperture in which it was previously formed.

Description

United States Patent [191 Reynolds et al.

[4 1 Dec. 10, 1974 [75] inventors: Charles Edward Reynolds, Camp Hill; Harold Oakley Woolley, Jr.,

Hershey, both of Pa.

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: June 14, 1973 [21] Appl. No.: 370,096

521 U.S. Cl. 200/5 A, 200/5 E, 200/16 R,

200/16 D, 200/159 B, 200/275, 200/284 51 1m. Cl. ..,,H0lh 13/74, HOlh 15/02 [58] Field of Search 20011 R, 5 R, 5 A, 5 E,

200/5 EA, 5 EB, 6 R, 6 B, 16 R, 85 R, 86 R, 86 A,6l.54-61.57, 159 B, 259,260, 275,

Goll 200/86 R X 3,699,294 10/1972 Sudduth 200/5 A X 3,715,541 2/1973 Koenig 200/85 A UX 3,742,157 6/1973 Leposavic 200/5 A Primary Examiner-James R. Scott [57] ABSTRACT A switch assembly has an apertured grate superimposed upon a contact board on which a plurality of independent electrical contacts are located. The apertures in the grate are respectively associated with the contacts to expose the contacts through the grate. A cross-curved elongated contact strip is operatively connected to the grate on the side thereof opposite the contacts in a predetermined position and configuration such that the strip is flexed between its points of connection to the grate in order to form a single projection which extends into one of the apertures and engages the contact associated therewith. The crosscurved contact strip flattens at the projection within the aperture because of the flexing of the strip, and thus holds the strip in that aperture until the strip is urged through another aperture in the grate, either manually or by a pushbutton or the like, thereby causing the projection in the strip to occur at the other aperture and relieving the projection at the aperture in which it was previously formedl 14 Claims, 11 Drawing Figures I I l I PATENTEU EEC] 01974 SHEET 10F 4 PATENTEBBEBIOW 3.854318 sum ear &

PATENTEL, DEC 1 0I974 sum 3 0r a The present invention relates to electrical switches, and more particularly to a selector switch which permits one circuit to be selected from a group of circuits.

Selector switches of various types have been previously proposed which will enable an operator to select one circuit from a group of circuits in order to perform a desired operation. Typically, such selector switches are provided with a plurality of pushbutton control members that are movable between two operative positions and interconnected with each other such that as any one of the control members is moved to one of its operative positions acontrol member previously in that operative position is returned to its other operative position. The problem with such pushbutton selector switches is that they require relatively complex arrangements of springs, plates or levers for interconnecting the respective control members in order that they operate in the desired manner. Moreover, the numberof control members or pushbuttons which can be operatively associated with each other in the control device is usually limited because of the complexity of the interconnections required to control the positions of the pushbuttons. Also, because of the complexity of such previously proposed pushbutton selector switches, it is relatively difficult to assemble the components in their housings and thus a relatively large amount of hand labor is required in order to complete the assembly. As a result, it is not possible to obtain a rapid production rate in the manufacture of such selector switches.

Accordingly, it is an object of the present invention movablecomponents. 1 A I Yet another object of the present invention is to provide a selector switch by which one circuit can be conveniently selected from a series of circuits.

Another objecto'f the present invention is to provide a selector switch which is relatively-inexpensive to produce and is durable in use. I

Another object of' the present invention is to provide a pushbutton device which requires a minimum of force in order to make the selected contact, and yet has sufficient strength to maintain the contact at all times until another circuit is selected.

In accordance with an aspect of the present invention a selector switch assembly is provided by which individual circuits can be selected by the engagement of a contact strip with contact elements positioned on a printed circuit board. The switchincludes a contact or printed circuit board having electrical contacts located thereon and an apertured grate which is operatively connected to the contact board on the side thereof containing the electrical contacts. The grate has a plurality of apertures formed therein which are respectively associated with each of the individual electrical contacts on the'contact board, therebyto expose the contacts through the grate. A resilient electrically conductive to provide a selector switch which has a minimum of common contact strip is operatively connected to the grate atthe opposite end portions thereof. The contact stripis cross-curved about its longitudinal axis and its length between the points'of connection thereof to the grate is greater than the distance between the points of connection so that the strip is thus flexed into a projection which extends towards and enters one of the apertures in the grate. As a result, the projection engages the contact member associated with the aperture in which it has entered.

Because of the cross-curved construction of the common contact strip, the strip has an unstable column strength and thus flattens across its width at the projection in an aperture; the flattening of the strip in this manner holds the strip in that aperture until the strip is urged through another aperture in the grate, either manually or by a pushbutton, thus causing the projection to occur at the other aperture and relieving the projection of the strip at the first aperture. As a' result, the first contact is broken and a new contact is made.

In one embodiment, means are provided for automatically relieving the projection when manual pressure is removed, whereby the switch can be used to make intermittent contacts.

, The above, and other objects, features and advantages of this invention, will be apparent in the following detailed description of illustrative embodiments thereof which are to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a selector switch constructed in accordance with one embodiment of the present invention;

FIG. 2 is an enlarged exploded perspective view of the selector switch illustrated in FIG. 1;

FIG. 3a is a sectional view taken alone line 3-3 of FIG. 1; 7

,FIG. 3b is a partial sectional view similar to FIG. 3a

.of another embodiment of the invention;

FIGS. 4 and 5 are sectional views of the contact strip used in the present invention taken along lines 4+4 and 5-5 respectively in FIG. 3a;

FIG. 6 is a sectional view, similar to FIG. 3, of another embodiment of the present invention;

FIG. 7 is a sectional view similar to FIG. 6, of yet another embodiment of the present invention;

FIG. 8 is asectional view of still another embodiment of the present invention; and 4 FIGS. 9 and 10 are partial exploded perspective views of two additional embodiments of the invention.

Referring now to the drawing in detail, and initially to FIGS. 1 and 2 thereof, it is seen that'a selector switch 10, constructed in accordance with the present invention, includes a plurality of pushbuttons l2 slidably includes a printedcircuit board element 16, also referred to hereinafter as a contact element or contact board, on which a plurality ofcontacts 18 are formed or otherwise positioned in any conventional manner in electrical contact withcircuit connections 15. Agrate plate 20, preferably formed of an electrical insulation material, is superimposed on theside 22 ofcontact board 16 on whichcontacts 18 are printed. The grate is provided with a plurality ofindependent apertures 24 which are located in the plate to be directly above and associated withindividual contact members 18, so that those contacts are exposed through the grate.

Acommon contact element 26 in the form of an elongated electrically conductive strip is provided in the switch assembly in order to allow an operator to make selective contact with thecontacts 18, thereby to select the desired electrical circuit. As would be apparent to those skilled in the art, the common connector strip may be connected in any convenient manner through external circuits to a source of current so as to form a complete electrical circuit with the circuits to which connectors are connected when the contact between the connector strip 26' and therespective contacts 18 is made, in the manner described hereinafter. However, in the embodiment of the invention illustrated in the drawing,connector strip 26 is provided with a permanent bend or corrugation 26' adjacent oneend 30 thereof, which corrugation extends through an opening 24' in grate into permanent contact with a contact 18' which is connected through a connector 15' on the printed circuit board to a source of current. Alternatively, corrugation can be eliminated andstrip 26 connected to the current source by a wire lead or the like in any convenient manner.

Contact strip 26 is connected tograte plate 20 and to contactboard 16, in any convenient manner, and preferably byrivets 28, as illustrated inFIGS. l and 2, at the opposite ends thereof. The contact strip is provided as a cross-curved metallic element (preferably of thin spring steel), i.e. an element which is curved about its longitudinal axis, transversely of its width. This is most clearly illustrated in the sectionalview of FIG. 4, wherein it is seen that in the normal relaxed configuration of thestrip 26,the strip maintainsa curved configuration in cross-section.

v In accordance with the present invention, the length of thestrip 26 between the points of connection '27 thereof to grate 20 is selected tobe somewhat longer than the distance betweenrivets 28. As a'result of this differential in' length, thestrip 26 will be flexed be tween itsends 30, i.e. between therivets 28, so as to form aprojection 32, as seen in FIG. 3. The difference inlength between the length of thestrip 26 and'the dis tance between therivets 28 determines the size ofprojections 32 and'that difference is selected so thatprojection 32 will contact one of thecontacts 18 through itsassociated aperture 24 ingrate plate 20. The selection of whichcontact 18 is engagedbyprojection 32 is made by depressing one of thebuttons 12, as described hereinafter. It'is noted that formation or movement ofprojection 32 does not effect corrugation 26' since, the latter is located on the other side of rivet 28'; thus the contact between'corrugation 26' and-contact 18' is always madeJ In addition,strip 26 may have gold strips or the like plated or otherwise secured thereto at the locations on its lower surface with which it engagescontacts 18. Such strips will allow the switch to accommodate heavy current flows therethrough.

Superimposed abovegrate 20 andcontact strip 26 is acover plate 33 connected to the switch'assembly byrivets 28.Cover plate 33 has a plurality ofapertures 34 formed therein which slidably receive pushbuttons 1 2. The latter have a complementary configuration in plan to the configuration ofapertures 24 and are provided with laterally extendingflanges 36 which prevent the buttons from being inadvertently withdrawn from the assembly. The buttons are freely slidably mounted in theapertures 34, except as limited by theflanges 36, and haveprojection portions 38 which are located to engage theupper surface 40 ofcontact strip 26, as seen most clearly in FIG. 3. In addition, an insulatingpad 42 is positioned between theprojections 38 ofpushbuttons 12 and theupper surface 40 ofcontact strip 26. Theinsulator pad 42 is preferably formed of a waterproof material such as nylon or silicon rubber and it serves to protect against inadvertent contacts with thestrip 26 throughplate 33 which may cause shorting in the circuits connected toconnectors 15. However, in certain applications this strip may be eliminated.

In the illustrative switch of the present invention, as shown in FIGS. l-3, the switch is adapted to be operated intermittently, that is contact of thestrip 26 with acontact 18 is maintained only as long as abutton 12 is held depressed. When the button is relieved, the strip will automatically return to a position out of engagement with the contact board. This is accomplished by the provision of a pair ofspacers 44 located at the opposite ends of the switch assembly. These spacers holdcover plate 33 sufficiently abovegrate plate 20 to accommodate the curved cross-sectional configuration ofcontact strip 26 and have downwardly bent ends 45 which engagestrip 26. The bent ends 45 ofspacers 44 bend strip 26'downwardly slightly into opening 47 inboard 20 and hold the strip bent at these locations thereby normally taking up the extra length of the strip betweenrivets 28 so that the strip normally remains straightabove grate 20. Thus, when one of the buttons, e.g. 12b, is depressed, it forms theprojection 32 and causes it to engage its associatedcontact 18b, as seen in FIG. 3, thereby urgingstrip 26 at its ends upwardly against bent ends 45 of the spacers. However, as soon as the pressure on button is relieved, the spring force of the bent ends of the spacers willovercome the tendency ofstrip 26 to maintainprojection 32 and thus will bend the strip intoopening 47, relieveprojection 32, and return the strip to its straight configuration overopening 24. On the other hand, where it is desired that thestrip 26 maintain its contact with acontact 18 for extended periods, i.e. not be intermittently operated, then the bent ends 45 ofspacers 44 are eliminated. In that case, as described hereinafter, thestrip 26, because of its configuration, will holdprojection 32 in contact with the selected contact until anotherbutton 12 is pushed.

This latter form of the invention is shown in FIG. 3b wherein it is seen that in the assembled configuration ofswitch 10, without the bent spacer ends 45,strip 26 is flexed, due to the differential in length between its ends and the points ofconnection 28 ongrate 20 so that aprojection 32 is automatically formed which will enter one of theapertures 24 in the grate and contact one ofthecontacts 18 oncontact board 16. Thus, for example, as shown in FIG. 3b, one of thecontacts 18b is engaged by theprojection 32. In that position thebutton 12b is, .in effect, depressed and slides into its lowermost position under the influence of gravity. On

the other hand, the remainingbuttons 12 remain in their uppermost position resting on theupper surface 40 ofstrip 26. In this position the buttons also prevent theprojection 32 from forming in a direction away fromgrate 20.

As a result of the cross-curved configuration ofstrip 26, the strip has an unstable column strength which makes it relatively easy to bend to formprojection 32. However, when the projection is formed, the curved strip tends to flatten out, at the apex of the projection, as illustrated in FIG. 5. (This occurs in all embodiments of the present invention.) This flattening of the crosscurved'band tends to hold the band in the flexed position, i.e. it serves to maintain the configuration ofprojection 32, until an outside force is placed onstrip 26 at some other location. In effect, the cross-curved band acts as an over the center member when the band is flexed into the curved position. That is, atprojection 32 the flexure of the strip causes the curved cross-section thereof to flatten out so that the center portion of the band moves downwardly, as seen in FIGS. 4 and 5, past a position at which the natural resiliency of the band will maintain its curved configuration. Once it has moved past that point, the band will maintain its flat configuration, or possibly even a reverse curved configuration until it is forced back in the opposite direction. This feature of the crosscurved strip enables the strip to maintain theprojection 32 at a fixed location during the operation of the switch of FIG. 3b until anotherbutton 12 is depressed.

It is noted thatalthough thestrip 26 is shown in the drawing as being positioned to curve or open towards grate andcontact 18, the strip can be placed in the reverse position to curve or .open towardscover plate 33 and will still operate in substantially the same manner, i.e. it will still flatten out atprojection 32 to hold the projection in its associatedgrate aperture 24.

When it is desired to engage thecommon contact strip 26 with another contact element, forexample contact 18a in FIG. 3b, pushbutton 12a'is manually-engaged and depressed againststrip 26 and into the aperture 24a associated therewith. As a result of the manual force applied to thepushbutton 12a,band 26 is depressed andprojection 32 is formed in theaperture 240 associated withcontact 18a. Because the force onpushbutton 12a forms theprojection 32 in this aperture, theprojection 32 inaperture 24b is relieved, and the band returns to its curved and relativelystraight I 20. It is noted for the purpose of simplifying thedrawprojection 32 in the selected configuration beneathpushbutton 12b, raising the latter to its uppermost position. Of course, in the embodiment of FIG. 3a this occurs automatically when pressure onpushbutton 12b is relieved due to the biasing effects of the spring bent ends ofspacers 44. In thatcase projection 32 is relieved and is not formed again until another pushbutton, e.g. 12a, is depressed and held down against the bias ofspacers 44. i

Because of the cross-curved configuration ofstrip 26, there is a positive snap action in theswitch assembly so that the contacts betweenthe'strip 26 and thecontacts 18 are made rapidly and positively. That is,projection 32 is rapidly snapped and unsnapped'at the respective locations of the.buttons 12 upon the actuation thereof. Thus, there is a clean, positivea'ction contact in the switch.

In another embodiment of the present invention illustrated in FIG. 6, a toggle switch element is utilized in lieu of thepushbuttons 12. As seen therein the toggle switch comprises an inverted Y-shaped member having astem 52 and a pair oflegs 54, 56 respectively. The toggle is pivotally mounted at 58 in the cover plate'33 of the switch assembly, withlegs 54, 56 being positioned aboverespective apertures 24 formed in grate ing, only twoapertures 24 have been shown in FIG. 6, however, it is to be understood that the switch shown therein can have multiple toggle switches respectively associated withadditional contacts 18 formed onboard 16. In this embodiment of the invention the switch is constructed in a similar manner to theswitch 10 in that acontact board 16 is provided withcontacts 18 formed thereon. Theapertured grate plate 20 is positioned in superimposed relation to the printedcircuit board 16, with theapertures 24 thereof exposing contact elements l8, and a cross-curvedcommon contact strip 26 is mounted above thegrate plate 20 between that plate and thecover 33. As will be appreciated by a careful consideration of FIG. 6, by rotatingtoggle member 50 in opposite directions, as indicated by thearrow 60 in the drawing,legs 54 and 56 will alternately be urged into contact withcommon contact strip 26, causing theprojection 32 to form in theaperture 24 in which the leg is inserted. The switch operates in substantially the same manner as the previously described switch of FIG. 3b in that the cross-curved contact member tends to flatten out in an over-the-center manner, to hold theaperture 24 until theswitch 50 is reversed.

Yet another embodiment of the invention is illustrated in FIG. 7 of the drawing. The switch.70 shown therein is similar in construction to the switch illustrated in FIG. 3b of the drawing, however, in lieu of thepushbutton members 12 aslide element 72 is mounted for sliding movement incover 33 between two extreme positions at the right and left side (not shown) of the switch along a straight path, indicated by the arrow 74, aboveopenings 24 ingrate 20.Slide element 72 has aresilient arm 76 secured thereto which is'adapted to slidingly engage theupper surface 40 of the crosscurvedcommon contact strip 26. As illustrated in FIG. 7, withleg 76 engaging thecontact strip 26 in this manner, it depresses the strip and formsprojection 32 therein which engages the contact element'l8a associated with theaperture 24 ingrate plate 20 thereabove. When theslide 72 is moved towards'the right, theleg 76 thereof causes theprojection 32 to be formed in thesuccessive apertures 24 while relieving theprojection v 32 in a prior aperture by applying sufficient force to the strip to overcome its tendency to hold the projection in the prioraperture. I

Another embodiment of the present invention is illustrated in FIG. 8 of the drawing. This embodiment is similar to that illustrated in FIG. 3, except that thepushbuttons 12 have been eliminated therefrom so that the switch can be directly operated manually. Thus, switch 80 includes acontact board 16 havingelectrical contacts 18 formed thereonat predetermined spaced locations along itsupper surface 22. Agrate 20 is mountedabovecontact board 16 in superimposed relation with theapertures 24 thereof respectively located above thecontacts 18. In addition, a cross-curvedmetallic contact strip 26 is mounted above andadjacent grate 20, with its length being selected to be larger than the distance between the points ofconnection 28 of the contact element to the grate so contact to form theprojection 32 therein.Cover 33 provides a series ofapertures 34 through which a finger can" be inserted to engage thecontact strip 26.'Theapertures 34 serve to confine the fingerpressure to the proper area over the desiredcontact element 18. i

In this embodiment of the invention thecontact strip 26 may be provided with an insulated coating on its exposed side, i.e. on its side facing theapertures 34. Alternatively, in certain applications, the contact element need not be insulated. For example, theselector switch 80 may be used in a vending machine wherein the selection is made prior to insertion in a coin in the machine; in that case there is no current through the switch until the coin is deposited. Thus, the purchaser simply makes a selection by inserting a finger in a selectedaperture 34 in order to urge thecontact strip 26 into engagement with theappropriate contact 18, thereby moving theprojection 32 into theappropriate aperture 24 adjacent the selected contact, and then deposits his coin. At that point, his finger is removed from the switch and the coin activates an additional switch which supplies current to the circuit. Thus, no insulation ofstrip 26 will be required.

In this embodiment of the invention the cross-curved contact strip operates in substantially the same manner as the embodiments which were previously described in that the curved configuration thereof provides unstable column strength in the strip which permits the strip to be readily flexed in the desired direction and which holds the flexed strip withprojection 32 in the appro-' priate aperture until an outside force is applied to the strip throughaseparate aperture 24.

FIGS. 9 and 10 of the drawings illustrate a portion of two additional embodiments of the present invention which are similar in construction to-the embodiment of FIG. 3b. Each of these embodiments is provided-with a contact strip compliance means 90, 100, respectively, formed therein. These compliance means serve to apply a compressive force in the longitudinal direction oftheirassociated contact strip 26, which aids the strip in maintaining theprojection 32 in a fixed position until an outside force is applied to the strip at another location. The compliance members are useful in the switches of the present invention because high tolerances between the respective lengths'of the contact 'strip 26, between the apertures or points ofconnection 27"therein, and the distance between therivets 28, such as is required to properly form theprojections 32, are sometimes difficult to produce, particularlyv in mass production operations. More specifically, in the structure of the present invention, particularly in the'embodiments described above, theprojection 32 is formedby the compression efiected upon the contact strip26 because of the greater length between the apertures or connection points 27 in the contact strip and the distance between therivets 28. Thus, the differential in these. distances or lengths is highly important in effecting the formation of theprojections 32 and small variations in the amount of this difference can seriously effect the operation of the switch. On the other hand, by the embodiments'of the invention shown in FIGS. 9 and 10 of the drawings, thecompliance members 90, 100, serve to apply a compression bias to thecontact strip 26 so that any variation in the toleranceof the -respective lengths of the strip and the distance between the points of connection, is overcome by the compression imposed on the strip from the compliance means.

More specifically; the Compliance means 90 shown in the modification of the switch'assembly in FIG. 9 of the drawings consists of a preformed and permanent corrugation in one end of thestrip 26 on the same side of theopening 27 therein as theprojections 32 to be formed.

Thecorrugation 90 is located to enter anopening 92 between itsopenings 27, but also by the corrugation or crimp in the strip provided by the compliance means 90. Thus, a bias compression stress or force is placed on thestrip 26 along its longitudinal axis by the compliance means 90. This force will hold theprojections 32 formed in the switch in a stable configuration until another pushbutton is pushed to form theprojection 32 at a different location, i.e. in adifferent aperture 24.

The embodiment of the invention illustrated in FIG. 10 of the drawing operates on the same principle as the compliance means discussed above with respect to FIG. 9. In this case, however, thecross-curved strip 26 is provided with anenlarged portion 102 having acentral aperture 104 formedtherein in order to define a pair of thin legs or connectingstrips 106. By this construction, when the switch is assembled withstrip 26 secured through itsopenings 27 to therivets 28, the strip is compressed to form aprojection 32 because of the difference between its length betweenopenings 27 and the distance between therivets 28. However, any difference in tolerance is accommodated by the compliance means 100, since thethin legs 106 thereof apply a longitudinal compressive force to the contact strip in the mounted assembly. Accordingly, the strip is maintained in compression and theprojections 32 formed therein will be held in a fixed position even if the relative lengths betweenopenings 27 and rivets 28 are not exactly correct. Thelegs 106, since they are formed of the same spring steel material as thestrip 26, have a relatively highspring rate, i.e. they constitute a relatively stiff spring which maintains a substantial compression stress on thestrip 26 to insure that theprojections 32 when formed hold their position and contact with their associated contact 'member l8.

Accordingly, it is seen that a relatively simple and inexpensive switch assembly is provided wherein only a single'moving part is utilized to provide a selection between a plurality of different electrical circuits. Moreover, this single moving element, i.e. the flexiblecrosscurved strip 26, is constructed so as to maintain the selected position as a result of its own configuration and strength rather than as a result of the application of outside forces by springs, latches or the like'as are required in previously proposed devices. As a further-result of the relatively simple construction of the invention, the switch assembly is inexpensive to produce and can be manufactured at relatively high production rates.

It will be apparent from the foregoing description that thecross-curved strip 26 should be of a suitable spring material for best results in the practice of the invention. Spring steel, preferably stainless spring steel, having the physical properties of the strip used to manufacture steel tape measures is a highly satisfactory material for thestrip 26. Other alloys such as berillum copper, phosphor bronze, or a suitable spring brass can be used.

Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of this invention.

What is claimed is:

l. A switch assembly comprising a contact board having a plurality of electrical contacts positioned thereon, an apertured grate operatively connected to said contact board adjacent said electrical contacts and having a plurality of apertures formed therein respectively associated with each of said electrical contacts to expose said contacts through the grate, and a resilient electrically conductive contact strip having opposite end portions respectively operatively connected to opposite ends of said grate at predetermined points of connection on the side of said grate opposite said contact board, said contact strip being cross-curved about its longitudinal axis, transversely of its width; the distance between said predetermined points of connection on said grate being less than the length of said contact strip between said points of connection whereby a portion of said strip is flexed into a projection extending towards and entering one of the apertures in said grate to engage the contact member associated with said one aperture; said cross-curved contact strip being flattened across its width at said projection by the flexing of thestrip thereby holding the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection and flattening of the strip at said one aperture; and means for maintaining one portion of said contact strip in electrical connection with an electrical conductor at all times, whereby said strip operates to provide an electrical connection between said conductor and a selected one of said contacts at substantially all times, in accordance with the selected location of said projection. 7 i

- 2 A switch device as defined in claim 1 wherein said grate is formed of an electrical insulating material.

3. A switch as defined in claim 1 including a cover plate operatively connected to said grate, said cover plate being located on the side of said contact strip'opposite saidgrate and having a plurality of apertures formed therein in position to be in alignment with the apertures in said grate. a

'4. A' switch asdefined inclaim 3 including a strip of insulating material positioned over said contact strip on the side thereof adjacent said cover plate.

5. A switch as defined inclaim 3 including a plurality of pushbuttons respectively slidably mounted in the ap ertures in said cover plate for movement towards and away from said contact board and having first end portions positioned adjacent said contact strip and adapted to be respectively urged into engagement with said strip and into their associated apertures in said grate to flex said strip and form said projection at their associated aperture in the grate to contact their associated contact member with said strip.

6. The switch as defined inclaim 3 wherein said contact strip is positioned with one curved side thereof opening towards said grate.

7. The switch as defined inclaim 3 including at least one toggle member pivotally mounted in said cover plate above and adjacent a pair of apertures therein; said toggle member including a pair of leg members positioned'to respectively enter said pair of apertures in said cover upon pivotal movement of said toggle be tween first and second positions.

8. The switch as defined in claim 1 including a cover plate operatively connected to said grate, said cover plate being located on the side of said contact strip opposite said grate and having an elongated aperture formed therein in substantially vertical alignment with the apertures in said grate; and an insulative slide member slidably mounted in said cover plate above said contact strip for movement in the aperture of the cover between first and second positions with respect to the apertures in said grate, said slide member having a resilient leg adapted to slidably engage said contact strip, said leg member being adapted to urge said contact strip into the aperture in the grate therebelow to form said projection.

9. The switch as defined inclaim 3 wherein said contact strip is formed of thin spring steel.

10. A switch assembly comprising, a contact board having a plurality of electrical contacts positioned thereon, a grate superimposed on and operatively connected to said contact board and having a plurality of apertures therein including apertures respectively located with respect to the contacts for exposing the contacts through the grate, and a cross-curved elongated contact strip operatively connected to said grate on the side thereof opposite said contacts in a predetermined position whereby the strip is flexed between its points of operative connection to the grate to form a projection extending into one of said apertures wherein the cross-curved strip is flattened across its width at said projection by the flexing of the strip thereby to hold the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection at said one aperture; and means for maintaining one portion of said contact strip in electrical connection with an electrical conductor at all times, hereby said strip operates to provide an electrical connection between said conductor and a selected one of said contacts in accordance with the selected location of said projection.

11. The switch assembly as defined in claim, 10 wherein said contact strip. has opposite end portions respectively connected to said grate at predetermined points of connection; the distance between said predetermined points of connection being less than the length of said contact strip between said points of connection whereby upon application of a force in a direction normal to said contact strip and towards said grate, said strip is flexed into a projection extending towards and entering one of the apertures in said grate to engage the contact member associated with said one aperture.

12. The switch assembly as defined in claim 11 including means in said assembly engaging said contact strip for urging the strip into a straight configuration above the apertures in said grate.

13. The switch assembly as defined in claim 11 wherein said distance and said lengths are selected in predetermined relation to each other such that flexing of said strip holds the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection at said one aperture.

' 14. The switch assembly as defined in claim 13 wherein said means comprises means for maintaining said one portion of said contact strip in'engagement with one of said electrical contacts on said board at all times.

Claims (14)

1. A switch assembly comprising a contact board having a plurality of electrical contacts positioned thereon, an apertured grate operatively connected to said contact board adjacent said electrical contacts and having a plurality of apertures formed therein respectively associated with each of said electrical contacts to expose said contacts through the grate, and a resilient electrically conductive contact strip having opposite end portions respectively operatively connected to opposite ends of said grate at predetermined points of connection on the side of said grate opposite said contact board, said contact strip being cross-curved about its longitudinal axis, transversely of its width; the distance between said predetermined points of connection on said grate being less than the length of said contact strip between said points of connection whereby a portion of said strip is flexed into a projection extending towards and entering one of the apertures in said grate to engage the contact member associated with said one aperture; said cross-curved contact strip being flattened across its width at said projection by the flexing of the strip thereby holding the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection and flattening of the strip at said one aperture; and means for maintaining one portion of said contact strip in electrical connection with an electrical conductor at all times, whereby said strip operates to provide an electrical connection between said conductor and a selected one of said contacts at substantially all times, in accordance with the selected location of said projection.

2. A switch device as defined in claim 1 wherein said grate is formed of an electrical insulating material.

3. A switch as defined in claim 1 including a cover plate operatively connected to said grate, said cover plate being located on the side of said contact strip opposite said grate and having a plurality of apertures formed therein in position to be in alignment with the apertures in said grate.

4. A switch as defined in claim 3 including a strip of insulating material positioned over said contact strip on the side thereof adjacent said cover plate.

5. A switch as defined in claim 3 including a plurality of pushbuttons respectively slidably mounted in the apertures in said cover plate for movement towards and away from said contact board and having first end portions positioned adjacent said contact strip and adapted to be respectively urged into engagement with said strip and into their associated apertures in said grate to flex said strip and form said projection at their associated aperture in the grate to contact their associated contact member with said strip.

6. The switch as defined in claim 3 wherein said contact strip is positioned with one curved side thereof opening towards said grate.

7. The switch as defined in claim 3 including at least one toggle member pivotally mounted in said cover plate above and adjacent a pair of apertures therein; said toggle member including a pair of leg members positioned to respectively enter said pair of apertures in said cover upon pivotal movement of said toggle between first and second positions.

8. The switch as defined in claim 1 including a cover plate operatively connected to said grate, said cover plate being located on the side of said contact strip opposite said grate and having an elongated aperture formed therein in substantially vertical alignment with the apertures in said grate; and an insulative slide member slidably mounted in said cover plate above said contact strip for movement in the aperture of the cover between first and second positions with respect to the apertures in said grate, said slide member having a resilient leg adapted to slidably engage said contact strip, said leg member being adapted to urge said contact strip into the aperture in the grate therebelow to form said projection.

9. The switch as defined in claim 3 wherein said contact strip is formed of thin spring steel.

10. A switch assembly comprising, a contact board having a plurality of electrical contacts positioned thereon, a grate superimposed on and operatively connected to said contact board and having a plurality of apertures therein including apertures respectively located with respect to the contacts for exposing the contacts through the grate, and a cross-curved elongated contact strip operatively connected to said grate on the side thereof opposite said contacts in a predetermined position whereby the strip is flexed between its points of operative connection to the grate to form a projection extending into one of said apertures wherein the cross-curved strip is flattened across its width at said projection by the flexing of the strip thereby to hold the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection at said one aperture; and means for maintaining one portion of said contact strip in electrical connection with an electrical conductor at all times, hereby said strip operates to provide an electrical connection between said conductor and a selected one of said contacts in accordance with the selected location of said projection.

11. The switch assembly as defined in claim 10 wherein said contact strip has opposite end portions respectively connected to said grate at predetermined points of connection; the distance between said predetermined points of connection being less than the length of said contact strip between said points of connEction whereby upon application of a force in a direction normal to said contact strip and towards said grate, said strip is flexed into a projection extending towards and entering one of the apertures in said grate to engage the contact member associated with said one aperture.

12. The switch assembly as defined in claim 11 including means in said assembly engaging said contact strip for urging the strip into a straight configuration above the apertures in said grate.

13. The switch assembly as defined in claim 11 wherein said distance and said lengths are selected in predetermined relation to each other such that flexing of said strip holds the strip in said one aperture until the strip is urged through another aperture in said grate, causing said projection to occur at said another aperture and relieving the projection at said one aperture.

14. The switch assembly as defined in claim 13 wherein said means comprises means for maintaining said one portion of said contact strip in engagement with one of said electrical contacts on said board at all times.

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