US3725907A

US3725907A - Pushbutton keyboard system

Info

Publication number: US3725907A
Application number: US00148503A
Authority: US
Inventors: H Boulanger
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 1971-06-01
Filing date: 1971-06-01
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: BR7203542D0; DE7220498U; AU6580374A; DE2226607A1; DE2226607B2; NL167527B; ES403288A1; AR202520A1; SU704477A3; GB1395647A; JPS5616446B1; NL7207456A; KR780000592B1; FR2141133A5; IT958121B; CA966181A; NL167527C

Abstract

A keyboard system in which a plurality of spaced sets of conductive members including U and rivet shaped are arranged at a surface of a support in electrical communication with conductive paths on an opposite surface of the support. A plurality of actuatable conductive elements, one for each set of conductive members, are provided to establish bridging electrical connection between conductive members of a set upon application of a preselected deflecting force to the conductive elements.

Description

United States Patent 91 Boulanger [54] PUSHBUTTON KEYBOARD SYSTEM [75] Henry J. Boulanger, Cumberland,

Assignee: Texas Instruments Dallas,Tex.

Filed: June 1, 1971 Appl. No.: 148,503

Inventor:

[7 3} Incorporated,

[451 Apr. 3, 1973 Krakinowski .200/1 R Redman ..200/l R Primary ExaminerDonald J. Yusko Assistant Examiner-Robert J. Mooney Attorney-Harold Levine, Edward J. Connors, Jr., John A. Haug, James P. McAndrews and Gerald B. Epstein [57] ABSTRACT [5-6] References Cited bets, are provided to establishbridgmg electrlcal connection between conductive members of a set upon UNITED STATES PATENTS application of a preselected deflecting force to the conductive elements. 3,600,528 8/1971 Leposavic ..200/5 3,627,927 12/1971 7 Schmitz ..178/l7 C 17 Claims, 7 Drawing Figures 44 t I m 48 9 I8 I I /4 4 42 PATH-HEDAPM 197a 37257907,

SHEET 1 [IF 5 .5? Henry iBoulcmger- PATENTEUAPM 1973 SHEET l UF 5 5) flemy J. Boa/anger l/VVE/VTOR BY Heng/ Boa/anger PUSHBUTTON KEYBOARD SYSTEM The present invention relates generally to keyboard systems and more particularly is directed to an improved pushbutton keyboard system for establishing electrical connections in response to actuation.

In recent years numerous types of keyboard systems have been developed for use in transmitting coded electrical information for incorporation in various types of business machines such as electronic calculators. Typically such keyboard systems utilize pushbutton members appropriately symbolized in a manner indicative of a numeric or mathematical function generated in response to depression of the pushbutton member to establish electrical connections between various conductive paths and/or various circuit elements coupled to the system in order to achieve a desired function. However, particularly as the cost of associated equipment has decreased dramatically in recent years coupled with an increase in the use and availability of various devices incorporating such systems the need has arisen for extremely inexpensive readily manufacturable keyboard systems which may be economically and accurately produced on a mass production basis with a high degree of accurate repeatability. For example, the need for miniaturized electronic calculators, units for addressing computer systems, credit card verifiers, etc., which necessarily require various types of keyboard arrangements has enormously increased in recent years requiring the provision of inexpensive and extremely durable keyboard systems which may be manufactured in a simple and economical manner on a relatively large volume basis-Particularly, in the computer field the need for durable, inexpensive keyboard systems which can accurately address electrical information either directly to a system or through a remote terminal or the like, while occupying a minimal amount of space, has become increasingly urgent.

Accordingly, it is an object of the present invention to provide an improved keyboard system adapted for selectively establishing electrical interconnections in response to mechanical actuation.

It is another object of the present invention to provide an improved pushbutton keyboard system in which actuation of individual pushbutton members establishes positive electrical interconnections for transmitting electrical information.

It is a further object of the present invention to provide an improved miniaturized pushbutton keyboard system which is relatively rugged and durable and which is extremely economical to fabricate on a mass production basis, and which is adapted for incorporation in various devices, such as electronic calculators, computer systems, etc.

Various additional objects and advantages of the present invention will become readily apparent from the following detailed description and accompanying drawings wherein:

FIG. 1 is an exploded perspective view illustrating a preferred embodiment of a keyboard system in accordance with the present invention;

FIG. 2 is a vertical sectional view through the keyboard system illustrated in FIG. 1;

' FIG. 3 is a partial plan view of the underside of the system illustrated in FIG. 2;

FIG. 4 is an exploded perspective view of an alternative embodiment of a keyboard system similar to that illustrated in FIG. 1;

FIG. 5 is a vertical sectional view through the keyboard system illustrated in FIG. 4;

FIG. 6 is a plan view of the underside of the system illustrated in FIG. 5; and

FIG. 7 is a perspective view illustrating a typical variety of electronic calculator incorporating a keyboard system such as that illustrated in the preceding embodiments.

Referring generally to the drawings, wherein corresponding elements in the various views are indicated by common reference numerals, and in particular initially to FIGS. 1-3, a keyboard system 10 in accordance with the present invention is illustrated. The system generally includes a non-conductive or insulating support member 12 having a generally planar first surface 14 on which a plurality of conductive paths 16 are disposed and arranged in a preselected pattern for transmitting electrical information in response to selective interconnection of portions thereof. At a second opposite surface 18 of the insulating support member 12 a plurality of sets 20 of conductive support members are provided which are arranged in a preselected configuration in electrical communication with first preselected portions of the conductive paths 16. Associated with each of the conductive support members are conductive contact members 22 similarly arranged at the second surface 18 of the insulating supporting layer in electrically isolated relationship with the conductive support members and in electrical communication with second preselected portions 16b of the conductive paths 16. A plurality of selectively actuatable conductive elements 24 are also arranged adjacent the second surface 18 of the insulating support layer and are respectively supported by and maintained in continuous electrical contact with each of the sets 20 of conductive support members and in selective disengagement with the associated conductive contact members 22. The conductive elements 24 are adapted to be deflected into a position of engagement with the conductive contact members 22 in response to the application of a preselected deflecting force thereto so as to establish a bridging electrical contact between one of the sets 20 of conductive support members and its associated conductive contact member 22, thereby electrically connecting the first and second preselected portions 16a, 16b of the conductive paths l6. Actuation of the conductive elements 24 so as to effect the establishment of the aforementioned bridging electrical connection may be effected in various ways, but in the illustrated embodiment it is accomplished by the provision of a plurality of manually actuatable pushbutton members 26 which are carried in a suitable casing 28 supported adjacent the second surface 18 of the insulating support member 12 whereby the application of a preselected deflecting force to the conductive elements 24 is effected by actuation of a selected pushbutton member 26 by the application of a mechanical force thereto such as through the fingertips of an operator. As a result of manual actuation of a selected pushbutton member 26 the preselected deflecting force is applied to the conductive element to effect deflection thereof into a position of engagement with the conductive contact member 22, thereby establishing the bridging electrical connection between the set of conductive support members 20 and the conductive contact member 22 and hence establishing an electrical connection between the first and second preselected portions 16a, 16b respectively of the conductive paths 16. In addition, if desired, a suitable device such as an integrated circuit shown in phantom and indicated generally by the reference numeral 30 may be carried by the insulating support member 12 and suitably connected to selected portions of the conductive paths 16 so as to process the signals established by the interconnection of various portions of the conductive paths in response to the establishment of the bridging electrical connections. Similarly, if desired, a power supply (not shown) may be also carried on the support member 12 to provide a selfcontained composite unit, or an external source of power may be utilized as the sole source of power or as an additional or alternative energy source.

More particularly, the insulating support member 12 is fabricated of a relatively rigid, non-conductive material which is adapted to provide support for the keyboard system, as well as associated electronic circuitry, power supplies, display means, etc., when the unit is to be incorporated in an electronic calculator system, a computer input system, etc. In this regard the member 12 may be fabricated of a suitable, relatively rigid, insulation material such as epoxy bonded glass cloth generally sold under the trade description G- by the Formica Company. The material may have a thickness of approximately 1 16th inch which has been generally found sufficient to provide adequate mechanical strength for a miniaturized device of this nature. As previously mentioned, the conductive paths 16 including the first and second preselected portions thereof 16a, 1612 respectively are arranged in a desired pattern at the first surface 14 (the underside of the support member 12, as illustrated in FIG. 2) in order to permit the transmission of electrical information in response to selective interconnection of various portions of the conductive paths upon the establishment of the bridging electrical connections. The pattern of conductive paths may be deposited on the surface 14 of the support layer utilizing conventional printed circuit art techniques, such as masking, etching, engraving etc. In addition, a plurality of apertures 32 are provided extending through the thickness of the support member 12 between the first surface 14 and the second surface 18 thereof so as to permit the selective establishment of electrical communication between the conductive paths at the surface 14 and the conductive support members 20 and contact members 22 arranged at the opposite surface 18. In this regard the apertures may be provided prior to or subsequent to the deposition of the conductive paths, thereby providing a pre-punched support board prepared for further fabrication operations.

In the illustrated embodiment the sets of conductive support members 20 are arranged to define a plurality of spaced 'sets of pairs of generally U-shaped, conductive members preferably comprising staples arranged at the surface 18 of the support layer 12. Such an arrangement has been found to be extremely advantageous in achieving enhanced case of fabrication of the system since the staples may be readily inserted through the apertures 32 in the pre-punched support member 12 utilizing suitable high-speed automated stapling equipment. Similarly, electrical communication may be conveniently established between these staples and selected portions of the conductive paths 16. As shown, the staples 20 each include a main body portion 34 of a generally looped configuration terminating in a pair of legs 36 which are received within the apertures 32 in the support layer 12. The apertures 32 are of a size sufficient to accommodate the legs 36 in a close-fitting relationship, while the outer ends of the legs are crimped against the surface 14 and are in contact with the selected portions of the conductive paths 16, such as the first preselected portions 16a. Consequently, a rigid mechanical connection is established and the electrical contact may be improved by soldering the crimped portions of the legs into position. In addition, as shown, the main body portion 34 of each of the staples comprising the plurality of sets of support members projects a first preselected distance outwardly from the surface 18 of the support member 12 so as to define conductive support areas spaced from the surface 18 for carrying the conductive elements 24. Similarly, the associated conductive contact members 22 are also illustrated as generally U-shaped conductive members, preferably comprising staples each having a main body portion 38 which terminates in a pair of legs 40 which project through apertures 42 extending through the thickness of the support member 12 similarly to the appertures 32, but providing communication with other portions of the conductive paths 16, such as the second preselected portions 16b. The legs 40 extend through the apertures 42 with the outer ends thereof being crimped against the surface 14 of the support layer 12 preferably in contact with other portions of the conductive paths 16, such as the second preselected portions 16b. The apertures 42 are of a size sufficient to accommodate the legs 40 of the staple 22 while the outer ends of the legs 40 are crimped against the surface 14 in contact with the second preselected portions 16b of the conductive paths to rigidly secure the staple to the member 12. In addition, the outer ends of the legs 40 crimped in position against the second preselected portions 16b of the conductive paths 16 may be soldered in this position to provide an improved electrical contact as shown. One of the contact staples 22 is arranged intermediate each of the pairs of support staples 20 and may be of slightly smaller gauge such that its main body portion 38 projects outwardly from the surface 18 a second preselected distance different than the first preselected distance which the body portion 34 of the support stapl'es 20 projects from the surfaces so as to facilitate maintenance of selective disengagement between the conductive elements 24 and the contact staples 22, as will be subsequently explained. The conductive support staples 20 and the conductive contact staples may be fabricated of various materials and material combinations depending upon the properties desired. For example, in one preferred embodiment the staples are fabricated of gold-plated nickel wire in order to provide a relatively non-reactive material having good surface contact properties. As other examples, the staples may be fabricated of goldplated stainless with a flash of nickel intermediate the central portion is subjected to a preselected deflecting force while automatically returning to its original position upon removal of the force, whereby the element is provided with a memory function. Of course, segments of other hollow bodies having double curved surfaces may be utilized in providing the conductive elements. The element 24 may be arranged such that it undergoes a snap-action deflection into its overcenter position in order to establish the aforementioned bridging electrical contact. In this regard referring particularly to FIG. 2, one of the elements indicated by the numeral 24a is shown in its overcenter position in response to actua- 7 tion by a depressed pushbutton member indicated by reference numeral 26a. However, it should be noted that in certain instances the central portion of conductive element 24 may be sufficiently closely spaced to the contact staple 22 that the element 24 need not be completely deflected into its overcenter position in order to contact the staple 22 for establishing the requisite bridging contact. Thus, upon application of the preselected deflecting force to the central portion of the conductive element 24 in response to actuation or depression of the pushbutton member 26 the element 24 is caused to undergo a snap-action deflection into its overcenter position. In addition, as a result of this snap-action deflection a tactile feed-back is provided which may be sensed in the finger tips of the operator actuating a particular pushbutton. Furthermore, an audible acknowledgment of deflection may accompany the snap-action deflection which may be further sensed by the operator as an additional indication of actuation of a pushbutton member to transmit a desired electrical signal. The conductive elements 24 preferably comprise gold-plated stainless steel discs and in one preferred embodiment may be fabricated of A.I.S.I. (American Iron and Steel Institute) Type 302 Stainless Steel, which comprises by weight approximately 0.15 percent carbon, 2.00 percent (max.) manganese, 1.00 percent (max.) silicon, 17 percent to 19 percent chromium, 8 percent to percent nickel and the balance iron, with a thin gold plating over its exposed contact surfaces.

Each of the conductive elements 24 is maintained in axial registry with the conductive contact staple 22 as sociated with each of the sets of support staples with the central portion thereof spaced from the contact staple 22. The marginal edges of the conductive elements 24 are supported on the main body portions 34 of the support staples 20 of each set such that the conductive element 24 is in continuous electrical contacttherewith and hence with the first preselected portions 16a of the conductive paths 16. Similarly, the central portion of the conductive elements 24 which are in registry with the main body portions 38 of the contact staples 22 remain in selective disengagement with the contact staples until deflected by actuation of a pushbutton member 26, whereupon the bridging electrical connection is established between a set of conductive support staples 20 and its associated conductive contact staple 22 and hence between the first and second preselected portions 16a, 16b of the conductive path 16.

In order to further support each of the conductive elements 24 and provide lateral restraint therefor a carrier sheet of insulating material 44 is disposed adjacent the surface l3 of the support member 12 overlying the plurality of sets of conductive support staples 20 and associated conductive contact staples 22. The sheet 44 includes a plurality of apertures 46 which are of a size sufficient to accommodate the conductive elements 24 therein and arranged in registry with the plurality of sets of conductive support staples 20 and the associated conductive contact staples 22. More particularly, the conductive elements 24 are disposed within the apertures 46, which are of a size slightly larger than the spacing intermediate the staples comprising each of the sets of conductive support staples. Accordingly the sheet 44 maybe maintained essentially in abutment with the surface 18 of the support member 12 with the main body portions 34 of the conductive support staples 20 which support the elements 24 extending slightly into the apertures 46. The conductive elements 24 are arranged within the apertures 46 and have opposed marginal portions resting on the main body portions 34 of the conductive support staples 20. Thus, support, as well as lateral restraint for the conductive elements 24 is provided. In addition, as may be noted, particularly in FIG. ll, each of the apertures 46 is of a preselected shape including a pair of opposed parallel walls 46a which are of a generally straight-line configuration, these generally straight-line wall portions being arranged to bound the main body portions 34 of the conductive support staples 20 which extend into the apertures 46. The other pair of opposed wall portions 46b of each of the apertures 46 are arranged in a generally curvilinear configuration curving outwardly from the center of the apertures 46 so as to more efficiently accommodate the generally circular conductive elements or discs 24. In this regard by virtue of providing the apertures 46 having a shape as illustrated certain advantages are achieved in that the overall space occupied by the apertures is minimized, since only one of the two dimensions of the apertures are increased while the other dimension is minimized, thereby maximizing the amount of material which remains to define the layer 44 in'order to enhance its structural strength and rigidity. This is advantageous in view of the small size of the layer 44 and the large number of apertures which are employed. The sheet 44 may be fabricated of a suitable nonconductive material such as a suitable glass cloth reinforced epoxy. In addition, the marginal portions of the sheet 44 which extend beyond the sets of support staples 20 at opposed sides of the support board 12 preferably are bonded or sealed to the marginal portions of support member 12 so as to facilitate the formation of an environmentally sealed unit.

In certain instances, it has been found desirable to further restrain the conductive elements 24 in their respective positions by providing a relatively thin, flexible sheet or film of an insulating force transmitting over-layer sheet or film 48, as shown, which is arranged intermediate the sheet 44 and the casing 28 which supports the pushbutton members 26. The over-layer 48 may comprise a material, such aspolyethylene terephthalate, commonly sold under the trade name Mylar, and may be suitably bonded or sealed to the exposed surface of the layer 44 and hence functions to prevent the conductive elements 24 from-inadvertently being removed or falling fromvtheir desired positions within the apertures 46, as well'as completing an environmental seal for the unit.

The pushbutton members 26 are each appropriately symbolized at their outer exposed surfaces in a manner indicative of the electronic function associated with actuation of a selected pushbutton member which establishes the requisite bridging electrical connection between the conductive support staples 20 and the conductive contact staple 22 and hence between the first and second preselected portions 16a, 16b of the conductive paths 16. In addition, each of the pushbutton similarly fabricated of a suitable rigid, non-conductive plastic material, or the like. In this regard each of the pushbutton members 26'include a flanged portion 52 which integrally extends from one pair of opposed lower edge surfaces thereof. These flange portions 52 are, adapted to be received within accommodating channels or slots 54 inthe casing 28 when the members 26 are positioned in the casing 28 to preclude lateral motion of the pushbutton elements 26 within the casing, while, permitting movement of the pushbutton members normal to the planar surface of the casing 28 upon actuation thereof. In addition, the casing 28 includes a pair of depending flange members 56 the spacing therebetween' being of'a size sufficient to accommodate the marginal edge portions 12a, 12b of the support member 12 if it is desired to provide an environmental seal between these marginal edge portions 12a, 12b and the inner surfaces of the flange members 56, when the casing 28 positioned in abutment with the overlayer sheet 48 with the pushbutton members aligned with the respective'conductive elements 24. Thus, in operation the pushbutton members are precluded from lateral movement within the casing but support staples 20 associated therewith.

Referring now to FIGS. 4-6 an alternate embodiment of a keyboard system similar to that illustrated in FIGS. 1-3 is shown in which a modified arrangement for carrying the conductive elements is provided. More particularly, in this embodiment a support member. of insulating material similar to the support member 12 is provided having a preselected pattern of conductive paths 62 arranged at a first surface 64vthereof while a plurality of sets of conductive supportmembers 66 are arranged at a second opposed surface 68of the board with an associated conductive contact member 70 being provided associated with each of the sets of con- .body ofth emembers 26. The casing 28 may be ductive support members spaced from and electrically isolated from the set of support members. The conductive support members 66 are adapted to be disposed in cooperating apertures 72 which are provided extending through the thickness of the support board between the first and

second surfaces

64, 68 so as to permit electrical communication to be established between each set of conductive support members 66 and first preselected portions 62a of the conductive paths 62,

when these conductive support membersare inserted the sets of conductive support members 66 is adapted to define a generally planar support area for supportingly receiving a conductive element 76 similar to the conductive element-24. The conductive element 76 is supported in continuous electrical contact with the set of support member 66 and hence in contact with the first preselected portions 62a of the conductive paths 62. In addition, the conductive element 76 remains in, selective disengagement with the associated conductive contact member and accordingly, each set of support members remains electrically isolated from its associated contact member 70 until deflection of the conductive element 76 is effected. Such deflection is accomplished in a mannersimilar to that described'in connection with the preceding embodiment in response to theapplication of a preselected deflecting force to the conductive element 76 to establish engagement between the conductive element 76 and the conductive contact member 70, thereby establishing a bridging electrical contact between the set of conductive support members 66 and the conductive contact member 70 and hence between the first and preselected

portions

62a, 62b of the conductive paths 62. The application of the preselected deflecting force to the conductive element 76 is again accomplished by the provision of a plurality of pushbutton members 78 maintained in registry with the respective conductive elements 76 such that actuation or depression of a pushbutton member 78 is effective to cause deflection of a conductive element in order to cause it to engage its associated conductive contact member thereby establishing the requisite bridging electrical contact. The pushbutton members 78 are similarly carried within a suitable support casing 80 which includes a plurality of slots 82 for receiving the body of the pushbutton members 78 therein, the pushbutton members being movable from a retracted to an actuating position in response to the application of a mechanical force to the exposed surfaces thereof, such as by manual actuation As previously mentioned, in accordance with an important advantage of the present invention a keyboard system is provided which is particularly suitable for fabrication by rapid, accurate, and inexpensive mass production techniques. The embodiment illustrated in FIGS. 4-6 similarly provides such advantages in that the support board 60 may be similarly provided in a prepunched configuration including the apertures 72, 74 for accommodating the conductive support members and the conductive contact members, while a desired pattern of conductive paths may be deposited on the surface 64 thereof utilizing conventional printed circuit art techniques to permit the selected electrical connections to be made between respective portions of the conductive paths. However, rather than employing staples, as in the preceding embodiment each of the sets of conductive support members 66 preferably comprises a plurality of collared rivets each of which includes a shank 82 and a flanged collar 84 with the shank adapted to be inserted in the aperture 72 while the collar 84 rests against the surface 68 of the support board, a portion of the shank projecting outwardly therefrom and the opposite end 86 of the shank is crimped against the surface 64 of the support member 60 in electrical contact with the first preselected portions 62a of the conductive path 62, thereby mechanically restraining the rivet in position with respect to the support member and the conductive path 62. In addition, the crimped end 86may be soldered in position to assure a good electrical contact with the first preselected conductive path 62a. In the illustrated embodiment each set 66 includes four of the previously described rivets arranged to define a generally enclosed area with the flanged collar portions 84 of each of the rivets defining a generally planar support area for the conductive element 76. It should be noted that a lesser or greater number of rivets, of course, may be utilized; In addition, the associated conductive contact member 70 is arranged generally centrally within the area defined by the four rivets 66 and preferably comprises a headed rivet including a shank portion 88 which is disposed within the aperture 74 with one end 90 being crimped against the surface 64 of the support board 60 as shown while its opposite end terminates in a head 92 of a larger diameter than the aperture 74 such that the rivet 70 is mechanically restrained with respect to the 1-3. The element 76 is arranged such that it similarly undergoes deflection movement into its overcenter position in order to establish the aforementioned bridging electrical contact between the set of support rivets 66 and the contact rivet 70 and hence between the first and second

preselected portions

62a, 62b of a preselected deflecting force to the central portion of V the conductive element 76 in response to actuation or depression of the selected pushbutton member 78 the element 76 is caused to undergo a snap-action deflection into its overcenter position and engages the head support member 60, subsequent to the crimping of its end 90 against the surface 64. The crimped end 90 is in electrical contact with the second preselected conductive path 62b and similarly may be soldered in position to assure a good electrical contact therewith. In addition, as shown the head 92 of the rivet 70 may be displaced outwardly from the surface 68 of the support member a lesser distance than the collar 84 of the support rivets 66 such that the central portion of the conductive element 76 may be maintained in selective disengagement therewith, as will now be explained in detail.

More particularly, the conductive elements 76 are generally similar to the elements 24, as described in connection with the embodiment illustrated in FIGS.

92 of the contact rivet thereby establishing an abrupt, instantaneous and positive bridging electrical contact between the support rivets 66 and the contact rivet 70 and hence between the first. and second

preselected portions

62a, 62b of the conductive paths 62. In addition, similarly to the preceding embodiment, as a result of this snap-action deflection a tactile feedback is provided which may be sensed in the finger tips of the operator actuating a particular push-button, and an audible acknowledgment of deflection may accompany the snap-action deflection and may be further sensed by the operator as an additional indication of actuation of a pushbutton member to transmit a desired electrical signal.

In order to further aid in maintaining the elements 76 -in position as well as to facilitate the formation of an environmental seal, it has been found advantageous in certain instances to provide an overlayer 94 of a flexible force transmitting material arranged intermediate the pushbutton members 78 and the conductive elements 76. In this regard lateral movement of the conductive elements 76 is precluded by virtue of the disposition of the elements 76 within the area defined by each of the sets of support rivets 66 resting on the flanged collar portions 84, with the marginal edges of the conductive elements 76 being laterally restrained by the portions of the shanks 82 which project outwardly beyond the collars 84. However, in order to prevent the elements 76 from being inadvertently removed from or falling from the unit the overlayer 94 may be provided, as shown, and may be suitably bonded to the marginal edge portions of the support board 60 to form an environmental seal. The overlayer 94 may be fabricated of a strong, flexible, thin insulation material, such as polyethylene terephthalate, commonly sold under the trade name Mylar.

As previously mentioned, the pushbutton elements 78 are suitably carried within the slots 82 in the casing and as shown have outer exposed surfaces which are appropriately symbolized in accordance with the electrical information which is to be transmitted in response to actuation thereof. In addition, a generally centrally located protruding member 96 extends from response to actuation or depression of the pushbutton members 78. A pushbutton member 780 is illustrated in FIG. in its depressed -or actuated condition to show the establishment of the bridging electrical contact between the set of conductive support rivets 66 and the conductive contact rivet 70, whereby the requisite bridging electrical contact is established between selected portions of the conductive paths 62. Each of the pushbutton members 78, similar to the preceding embodiment, also may include a pair of opposed flanges 97 which are adapted to be received in cooperating channels 98 in the wall of the slots 82 in the casing to provide improved lateral support for the pushbutton members 76. The casing 80 also preferably includes a pair of depending flange portions 99 extending along its longitudinal edges spaced apart a distance slightly greater than the lateral dimension of the support member 60 so that the inner portions of the flanges 99 may be sealed to the marginal edges of the support member 60 if it is desired to provide an environmentally sealed unit. The casing 80 as well as the pushbutton members 78 may be fabricated of a suitable insulating plastic material.

In operation it may be seen that similarly to the embodiment illustrated in FIGS.- 1-3 the actuation or depression of a selected pushbutton member 78 effects deflection of its associated conductive element 76 so as to effect the establishment of the bridging electrical contact between the support rivets 66 and the contact rivet 70 and hence between the first and second

preselected portion

62a, 62b of the conductive paths 62 so as to permit the transmission of an appropriate electrical signal. In addition, as illustrated in FIGS. 4 and 6, if desired, suitable semiconductor devices or the like illustrated in phantom as a dual-in-line package integrated circuit 100 may be provided with its lead members 102 extending through suitable apertures 104 in the support board 60 and maintained in contact with requisite portions of the conductive paths 62 so as to selective couple the various circuit elements thereof (not shown) to the paths 62 in order to process the electronic information being transmitted upon interconnection of selected portions of the conductive paths. Similarly, if desired, a suitable power supply means (not shown) may be also mounted on the support member 60.

. Referring to the FIG. 7 embodiment a composite unit indicated generally by the reference numeral 104 is illustrated, including a plurality of pushbutton members 106 supported within a causing 108 which is mounted in overlying relationship with a support board 110 which may include conductive support areas, conductive contact areas, conductive elements, conductive paths etc., all as shown and described in the preceding embodiments. In addition, the unit 104 includes a visual display window 1 12 so as to provide a visual indication of operation of the unit when it is being utilized as an electronic calculator, for example, as an input to a computer system, etc. Similarly, if desired, the unit 104 may include a suitable print out mechanism to provide a permanent record, if desired.

Thus, a unique keyboard system has been described in detail in which a particularly advantageous bridging electrical contact system is provided the system being 'particularly adapted for incorporation in various systems such as electronic calculators, computer systems, etc.

Various changes and modifications in the abovedescribed embodiments will be readily apparent to those skilled in the art and any of such changes of modifications are deemed to be within the spirit and scope of the present invention as set forth in the appended claims.

I claim:

1. A selectively energizable keyboard system comprising an electrically insulating support member having a generally planar first surface on which a plurality of conductive paths are disposed arranged in a preselected pattern adapted to transmit electrical information in response to selective interconnection of por-' tions of said paths,

a plurality of spaced apart setsof conductive support members arranged in a preselected configuration at a second opposite surface of said support member in electrical communication with first preselected portions of said paths,

conductive contact members associated with each of said plurality of sets of conductive support members, said contact members being arranged at said second surface of said support member each in electrically isolated relationship with its associated conductive support member and in electrical communication with second preselected portions of said paths, and

a plurality of selectively actuatable conductive elements adjacent said second surface, one of said elements being supported by and maintained in continuous electrical contact with each of said sets of conductive support'members and in selective disengagement with said conductive contact member, said conductive elements being adapted to be deflected into a position of engagement with said conductive contact member so as to establish an electrical connection between said first and said second preselected portions of said paths in response to the application of a preselected deflecting force to said conductive element.

2. A-system in accordance with claim 1 wherein means are provided for applying the preselected deflecting force to said conductive elements, including a plurality of pushbutton members adapted. to. be manually actuated to apply the deflecting force to said conductive elements to effect deflection thereof into a position of engagement with said conductive contact member, each of said pushbutton members having a force applying surface in registration with a conductive element and another surface adapted to be symbolized in a manner indicative of the electrical information transmitted in response to the establishment of the electrical connection between said first and said second preselected portions of said paths.

3. A system in accordance with claim 1- wherein each of said sets of conductive support members-include a plurality of spaced first metallic members arranged to define at least a partially enclosed area at said second surface of said insulating support member, said first metallic members extending through said insulating support member and terminating in electrical contact with said first preselected portions of said conductive paths.

, support for said conductive element.

6. A system in accordance with claim 5 wherein said second metallic members project outwardly a second preselected distance less than said first preselected distance from said second surface of said insulating support member so as to remain spaced from said conductive element until said conductive element is deflected into engagement therewith so as to establish the bridging electrical connection between the set of conductive support members and the associated conductive contact member.

7. A system in accordance with claim 6 wherein said conductive elements are each of a generally circular configurationhaving marginal edge portions supported on the generally planar support defined by said first metallic members and a generally central portion maintained in selective disengagement with and adapted to be deflected into engagement with said conductive contact member, said conductive elements each having a convex surface of curvature adapted to receive the preselected deflecting force in registration with an associated conductive contact member, said convex surface being adapted to be deflected into a concave configuration in engagement with said conductive contact member in response to the application of the preselected force.

8. A system in accordance with claim 7 wherein a relatively thin flexible insulating, force-transmitting overlayer is secured to said insulating support board in overlying relationship with respect to said conductive elements so as to maintain said conductive elements in a position supported by said first, metallic members.

9. A system in accordance with claim 6 wherein said first metallic members each comprise a generally U- shaped member including a pair of legs extending through apertures in said insulating support member and being rigidly crimped into position at said first sur face of said insulating support member in electrical contact with said first preselected portions of said conductive paths and an integral body member joining said legs, said body being supported at said second surface of said insulating support member and projecting outwardly therefrom said first preselected distance, and said second metallic members each comprise a generally U-shaped member including a pair of legs extending'through apertures in said insulating support member and being rigidly crimped into position at said first surface of said insulating support member in electrical contact with said second preselected portions of said conductive paths and an integral body member joining said legs, said body being supported at said second surface of said insulating support member and projecting outwardly therefrom said second preselected distance.

10. A system in accordance with claim 9 wherein said first metallic members comprise a pair of staples secured to said insulating support member, each of said sets of conductive support members includingsaid pair of staples separated by a preselected distance to define the generally planar support for said conductive elements, and said second metallic member comprises another staple secured to said insulating support member intermediate said pair of staples.

11. A system in accordance with claim 10 wherein said conductive elements are each of a generally circular configuration having opposed marginal potions supported on said pair of staples and having a generally central portion spaced from and maintained in selective disengagement with said another staple and adapted to be deflected into engagement with said another staple in response to the application of the preselected deflecting force to said conductive element thereby establishing a bridging electrical contact between said pair of staples and said another staple so as to effect an electrical connection between said first and second preselected portions of said conductive paths.

12. A system in accordance with claim 6 wherein said first metallic members each include a shank extending through an aperture in said insulating support member and having an annular collar at one end of a greater diameter than the aperture to preclude complete passage of said shank through the aperture, said collar abutting said second surface of said insulating support member and defining a portion of the planar support for one of said conductive elements, the opposite end of said shank being crimped against said first surface of said insulating support member to effect rigid emplacement of said first metallic member, and said second metallic member each include a shank extending through an aperture in said insulating support member and having a head at one end of a greater diameter than the aperture to preclude complete passage of the shank therethrough, said head abutting said second surface of said insulating support member, the opposite end of said shank being cramped against said first surface of said insulating support member to effect rigid emplacement of said second metallic member.

13. A system in accordance with claim 12 wherein said first metallic members comprise collared rivets secured to said insulating support member, each of said sets of conductive support members including a plurality of collared rivets spaced to accommodate said conductive elements in supporting relationship on said annular collars, and said second metallic member comprises a headed rivet generally centrally located with respect to said set of collared rivets.

14. A system in accordance with claim 13 wherein said conductive elements are each of a generally circular configuration having a marginal boundary supported on said annular collars of said collared rivets and having a generally central portion spaced from and maintained in selective disengagement with said headed rivet and adapted to be deflected into engagement therewith in response to the application of the preselected deflecting force to said conductive element thereby establishing a bridging electrical contact between said set of collared rivets and said headed rivet so as to effect an electrical connection between said first and second preselected portions of said conductive paths.

15 A selectively energizable keyboard system comprising an electrically insulating support board having a first surface carrying a plurality of conductive paths arranged in a preselected pattern and adapted to transmit electrical information in response to selective interconnection of portions thereof,

a plurality of spaced sets of conductive staples arranged in a preselected configuration at a second opposite surface of said support board to define a plurality of generally planar support areas the ends of each of said staples extending through apertures in said support board and terminating in electrical contact with first preselected portions of said conductive paths,

a plurality of associated conductive staples at said second surface, one of said associated staples being arranged intermediate the staples in each of said sets and electrically isolated therefrom, the ends of each of said associated staples extending through apertures in said support board and terminating in electrical contact with second preselected portions of said conductive paths,

a. plurality of selectively actuatable, generally circular, conductive discs adapted to undergoflexing movement in response to the application of a preselected deflecting force thereto respectively disposed on said planar support areas with marginal portions thereof supported by and maintained in substantially stationary electrical contact with said sets of conductive staples and the central portion thereof is selective disengagement with said associated conductive staples, the central portions of said conductive discs being adapted to be deflected into a position of engagement with said associated conductive staples so as to establish a bridging electrical contact between a set of conductive staples and its associated conductive staple, thereby electrically connecting said first and second preselected portions of said conductive paths in response to the application of a preselected deflecting force to said conductive element,

an overlayer of insulating material supported at said second surface of said support board, said overlayer including a plurality of apertures exposing said sets of conductive staples and said associated staples, said apertures being adapted to accommodate said conductive discs to restrain lateral 1 movement thereof while permitting deflection thereof, and means for applying the preselected deflecting force to said conductive discs including a plurality of pushbutton members adapted to be manually actuated to apply the preselected deflecting force to said conductive discs to effect deflection of the central portion thereof into a position of engagement with said associated conductive staple, each of said pushbutton members havinga force applying surface in registration with a conductive disc and an exposed surface adapted to be symbolized in a manner indicative of the electrical information transmitted in response to the establishment of the electrical connection between said first and second portions of said conductive paths.

16. In an electronic calculator;

a pushbutton keyboard system adapted to enter electrical information in response to actuation, said keyboard system including an insulating support board having a first surface on which a plurality of conductive paths are arranged in a preselected pattern and adapted to transmit electrical information in response to energization thereof, 1

a plurality of spaced sets of conductive support members arranged in a preselected configuration at a second opposite surface of said insulating support board to define a plurality of support areas spaced from said second surface and in electrical communication with first preselected portions of said conductive paths, 7

a plurality of conductive contact members associated with said plurality of support members one of said contact members being arranged within the area defined by each of said sets of contact members and in electrical communication with second preselected portions of said conductive paths,

a plurality of selectively actuatable, generally circular, conductive discs respectively disposed on said support areas with marginal portions thereof supported by and maintained in substantially stationary electrical contact with said support members the central portions thereof being in selective disengagement with said associated contact members and being adapted to be deflected into a position of engagement with said associated contact member in response to the application thereto of a preselected deflecting force so as to establish a bridging electrical connection between a set of conductive support members and its associated conductive contact member, thereby electrically connecting said first and said second preselected portions of said conductive paths,

means disposed adjacent said second surface for restraining movement of said conductive disc's other than flexing movement thereof, and

means for applying the preselected deflecting force to said conductive elements including a plurality of pushbutton members adapted to be actuated to apply the preselected deflecting force to said conductive discs to effect deflection of the: central portion thereof into a position of engagement with the associated conductive contact member, each of said pushbutton members having a force applying surface adjacent a conductive disc and an exposed surface adapted to be symbolized in a manner indicative of the electrical information to be transmitted by the establishment of the bridging electrical connection between said first and second portions of said first and second conductive paths.

17. A selectively energizable keyboard system comprising an electrically insulating support member having a generally planar first surface on which a plurality of conductive paths are disposed arranged in a preselected pattern adapted to transmit electrical information in response to selective interconnection of pottions of said paths, I

a plurality of spaced apart generally U-shaped first conductive members arranged in a preselected configuration at a second opposite surface of said support member, the ends of each first member extending through apertures in the support member and terminating in electrical communication with first preselected portions of said paths,

a plurality of generally U-shaped second conductive members, a second member associated with each of said first conductive members, said second conductive members being arranged at said second surface of said support member each in electrically isolated relationship with its associated first conductive member, the ends of each second member extending through apertures in the support member and terminating in electrical communication with second preselected portions of said paths,

a plurality of selectively actuatable conductive ele-

Claims

1. A selectively energizable keyboard system comprising an electrically insulating support member having a generally planar first surface on which a plurality of conductive paths are disposed arranged in a preselected pattern adapted to transmit electrical information in response to selective interconnection of portions of said paths, a plurality of spaced apart sets of conductive support members arranged in a preselected configuration at a second opposite surface of said support member in electrical communication with first preselected portions of said paths, conductive contact members associated with each of said plurality of sets of conductive support members, said contact members being arranged at said second surface of said support member eaCh in electrically isolated relationship with its associated conductive support member and in electrical communication with second preselected portions of said paths, and a plurality of selectively actuatable conductive elements adjacent said second surface, one of said elements being supported by and maintained in continuous electrical contact with each of said sets of conductive support members and in selective disengagement with said conductive contact member, said conductive elements being adapted to be deflected into a position of engagement with said conductive contact member so as to establish an electrical connection between said first and said second preselected portions of said paths in response to the application of a preselected deflecting force to said conductive element.

2. A system in accordance with claim 1 wherein means are provided for applying the preselected deflecting force to said conductive elements, including a plurality of pushbutton members adapted to be manually actuated to apply the deflecting force to said conductive elements to effect deflection thereof into a position of engagement with said conductive contact member, each of said pushbutton members having a force applying surface in registration with a conductive element and another surface adapted to be symbolized in a manner indicative of the electrical information transmitted in response to the establishment of the electrical connection between said first and said second preselected portions of said paths.

3. A system in accordance with claim 1 wherein each of said sets of conductive support members include a plurality of spaced first metallic members arranged to define at least a partially enclosed area at said second surface of said insulating support member, said first metallic members extending through said insulating support member and terminating in electrical contact with said first preselected portions of said conductive paths.

4. A system in accordance with claim 3 wherein said conductive contact members each comprise a second metallic member arranged generally centrally within said partially enclosed area at said second surface of said insulating support member, said second metallic member extending through said insulating support member and terminating in electrical contact with said second preselected portions of said conductive paths.

5. A system in accordance with claim 4 wherein said first metallic members project outwardly a first preselected distance from said second surface of said insulating support member to define a generally planar support for said conductive element.

7. A system in accordance with claim 6 wherein said conductive elements are each of a generally circular configuration having marginal edge portions supported on the generally planar support defined by said first metallic members and a generally central portion maintained in selective disengagement with and adapted to be deflected into engagement with said conductive contact member, said conductive elements each having a convex surface of curvature adapted to receive the preselected deflecting force in registration with an associated conductive contact member, said convex surface being adapted to be deflected into a concave configuration in engagement with said conductive contact member in response to the application of the preselected force.

8. A system in accordance with claim 7 wherein a relatively thin flexible insulating, force-transmitting overlayer is secured to said insulating support boarD in overlying relationship with respect to said conductive elements so as to maintain said conductive elements in a position supported by said first metallic members.

9. A system in accordance with claim 6 wherein said first metallic members each comprise a generally U-shaped member including a pair of legs extending through apertures in said insulating support member and being rigidly crimped into position at said first surface of said insulating support member in electrical contact with said first preselected portions of said conductive paths and an integral body member joining said legs, said body being supported at said second surface of said insulating support member and projecting outwardly therefrom said first preselected distance, and said second metallic members each comprise a generally U-shaped member including a pair of legs extending through apertures in said insulating support member and being rigidly crimped into position at said first surface of said insulating support member in electrical contact with said second preselected portions of said conductive paths and an integral body member joining said legs, said body being supported at said second surface of said insulating support member and projecting outwardly therefrom said second preselected distance.

10. A system in accordance with claim 9 wherein said first metallic members comprise a pair of staples secured to said insulating support member, each of said sets of conductive support members including said pair of staples separated by a preselected distance to define the generally planar support for said conductive elements, and said second metallic member comprises another staple secured to said insulating support member intermediate said pair of staples.

15. A selectively energizable keyboard system comprising an electrically insulating support board having a first surface carrying a plurality of conductive paths arranged in a preselected pattern and adapted to transmit electrical information in response to selective interconnection of portions thereof, a plurality of spaced sets of conductive staples arranged in a preselected configuration at a second opposite surface of said support board to define a plurality of generally planar support areas the ends of each of said staples extending through apertures in said support board and terminating in electrical contact with first preselected portions of said conductive paths, a plurality of associated conductive staples at said second surface, one of said associated staples being arranged intermediate the staples in each of said sets and electrically isolated therefrom, the ends of each of said associated staples extending through apertures in said support board and terminating in electrical contact with second preselected portions of said conductive paths, a plurality of selectively actuatable, generally circular, conductive discs adapted to undergo flexing movement in response to the application of a preselected deflecting force thereto respectively disposed on said planar support areas with marginal portions thereof supported by and maintained in substantially stationary electrical contact with said sets of conductive staples and the central portion thereof is selective disengagement with said associated conductive staples, the central portions of said conductive discs being adapted to be deflected into a position of engagement with said associated conductive staples so as to establish a bridging electrical contact between a set of conductive staples and its associated conductive staple, thereby electrically connecting said first and second preselected portions of said conductive paths in response to the application of a preselected deflecting force to said conductive element, an overlayer of insulating material supported at said second surface of said support board, said overlayer including a plurality of apertures exposing said sets of conductive staples and said associated staples, said apertures being adapted to accommodate said conductive discs to restrain lateral movement thereof while permitting deflection thereof, and means for applying the preselected deflecting force to said conductive discs including a plurality of pushbutton members adapted to be manually actuated to apply the preselected deflecting force to said conductive discs to effect deflection of the central portion thereof into a position of engagement with said associated conductive staple, each of said pushbutton members having a force applying surface in registration with a conductive disc and an exposed surface adapted to be symbolized in a manner indicative of the electrical information transmitted in response to the establishment of the electrical connection between said first and second portions of said conductive paths.

16. In an electronic calculator; a pushbutton keyboard system adapted to enter electrical information in response to actuation, said keyboard system including an insulating support board having a first surface on which a plurality of conductive paths are arranged in a presElected pattern and adapted to transmit electrical information in response to energization thereof, a plurality of spaced sets of conductive support members arranged in a preselected configuration at a second opposite surface of said insulating support board to define a plurality of support areas spaced from said second surface and in electrical communication with first preselected portions of said conductive paths, a plurality of conductive contact members associated with said plurality of support members one of said contact members being arranged within the area defined by each of said sets of contact members and in electrical communication with second preselected portions of said conductive paths, a plurality of selectively actuatable, generally circular, conductive discs respectively disposed on said support areas with marginal portions thereof supported by and maintained in substantially stationary electrical contact with said support members the central portions thereof being in selective disengagement with said associated contact members and being adapted to be deflected into a position of engagement with said associated contact member in response to the application thereto of a preselected deflecting force so as to establish a bridging electrical connection between a set of conductive support members and its associated conductive contact member, thereby electrically connecting said first and said second preselected portions of said conductive paths, means disposed adjacent said second surface for restraining movement of said conductive discs other than flexing movement thereof, and means for applying the preselected deflecting force to said conductive elements including a plurality of pushbutton members adapted to be actuated to apply the preselected deflecting force to said conductive discs to effect deflection of the central portion thereof into a position of engagement with the associated conductive contact member, each of said pushbutton members having a force applying surface adjacent a conductive disc and an exposed surface adapted to be symbolized in a manner indicative of the electrical information to be transmitted by the establishment of the bridging electrical connection between said first and second portions of said first and second conductive paths.

17. A selectively energizable keyboard system comprising an electrically insulating support member having a generally planar first surface on which a plurality of conductive paths are disposed arranged in a preselected pattern adapted to transmit electrical information in response to selective interconnection of portions of said paths, a plurality of spaced apart generally U-shaped first conductive members arranged in a preselected configuration at a second opposite surface of said support member, the ends of each first member extending through apertures in the support member and terminating in electrical communication with first preselected portions of said paths, a plurality of generally U-shaped second conductive members, a second member associated with each of said first conductive members, said second conductive members being arranged at said second surface of said support member each in electrically isolated relationship with its associated first conductive member, the ends of each second member extending through apertures in the support member and terminating in electrical communication with second preselected portions of said paths, a plurality of selectively actuatable conductive elements, and means mounting said conductive elements adjacent said second surface, a respective element being mounted contiguous to each second conductive member and its associated first conductive member, said conductive elements being adapted to be deflected into a position of engagement with their respective first and second conductive contact members so as to establish an electrical connection between said first and said second preselected portions of said paths in response to the application of a preselected deflecting force to said conductive elements.