PUSHBUTTON KEYBOARD SWITCH ASSEMBLY WITH IMPROVED OVER CENTER DIAPHRAGM CONTACT

• US 3,684,842 A
• Filed: 07/01/1970
• Issued: 08/15/1972
• Est. Priority Date: 07/01/1970
• Status: Expired due to Term

• Current Assignee: Henry J. Boulanger
• Original Assignee: Henry J. Boulanger
• Inventors: Boulanger, Henry J.
• Primary Examiner(s): Scott, J. R.
• Application Number:
  US05/051,464
• Time in Patent Office: 776 Days
• Field of Search: 200/5R,5A,46,86R,159B 340/166R
• US Class Current: 200/5.00R
• CPC Class Codes: G04C 3/005 Multiple switches G04C3/004 takes precedence
• CPC Class Codes: H01H 13/7006 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
• CPC Class Codes: H01H 2203/026 on different planes
• CPC Class Codes: H01H 2205/03 Apertured plate
• CPC Class Codes: H01H 2215/036 Metallic disc
• CPC Class Codes: H01H 2227/026 Separate dome contact
• CPC Class Codes: H01H 2233/004 One molded part
• CPC Class Codes: H04M 1/23 Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof by improving visibility H04M1/22

Abstract

A selectively energizable keyboard system is disclosed including a plurality of selectively actuatable pushbutton members having exposed surfaces adapted to be symbolized in accordance with electronic functions generated by actuation of the pushbutton members, and having opposed surfaces adapted to transmit force in response to actuation. A plurality of conductive elements are supported in registration with the opposed surfaces of the pushbutton members, each having a dished surface of curvature when in an unactuated condition and adapted to be deflected into an over-center position in response to application of force by a pushbutton member. A conductive member having a plurality of contact areas in electrical contact with the conductive elements is arranged adjacent the set of conductive elements. In addition, a plurality of conductive paths are arranged at a surface of a support member facing the conductive member. Each of the conductive paths is adapted to be electrically connected to the conductive member through one of the conductive elements, when the conductive element is deflected into its over-center position.

Claims

1. A selectively energizable keyboard system comprising a set of selectively operable pushbutton members each movable in one direction from a retracted to an activating position, each of said pushbutton members having an exposed surface adapted to receive the application of a preselected mechanical force to effect movement into said activating position and having an opposed surface adapted to transmit said force, a set of conductive elements in registration with respective opposed surface of said pushbutton members, each of said elements having a dished surface of curvature when in an unactuated condition, said surface being in abutment with said opposed surface of one of said pushbutton members and adapted to be deflected into an over-center position in response to the application of said preselected force transmitted by actuation of said pushbutton member, a generally planar conductive member disposed adjacent said set of conductive elements, said conductive member including a plurality of contact sections arranged in electrical contact with said conductive elements, and a support member having a plurality of conductive paths arranged at a surface thereof in spaced facing relationship with said plurality of sections of said conductive member, selected ones of said conductive paths being electrically connected to said conductive member through a bridging electrical connection established between said conductive member and one of said conductive elements only when said conductive element is in an over-center position.

2. A system in accordance with claim 1 wherein means are provided for supportingly carrying and restraining said set of conductive elements against lateral movement relative to said opposed surfaces of said pushbutton members and relative to said conductive paths to assure positive electrical contact between said conductive elements and said selected conductive paths through said conductive elements in response to actuation of preselected pushbutton members.

3. A system in accordance with claim 1 wherein said conductive elements preclude electrical contact between said conductive paths and said conductive member until respective conductive elements are subjected to said preselected force required for deflection into its over-center position in response to actuation by an associated pushbutton member, said preselected force being at least partially stored to effect an aBrupt snap-action deflection of said conductive element into its over-center position, thereby effecting a positive instantaneous electrical contact between said conductive member and said selected conductive path through said conductive element.

4. A system in accordance with claim 3 wherein said pushbutton members are adapted to be individually manually actuatable and said conductive elements are adapted to produce a tactile stimulation transmittable through said associated pushbutton member in response to the snap-action deflection into the over-center position.

5. A system in accordance with claim 3 wherein each of said conductive elements is of a generally circular configuration having a preselected diameter, said conductive member includes a plurality of generally circular apertures, said apertures being in axial registration with said conductive elements and having a diameter less than said preselected diameter but sufficient to accommodate deflection of the central portion of said conductive elements therethrough, and at least a portion of each of said conductive paths is arranged in registration with said apertures to permit the making of a bridging electrical connection between each of said paths and the conductive member through the conductive element in response to deflection thereof.

6. A system in accordance with claim 5 wherein each of said apertures in said conductive member is defined by an annular contact area circumscribing said aperture, said annular contact area being in electrical contact with an associated one of said conductive elements to effect selective electrical contact between the conductive path in registration with said aperture and said annular contact area through said conductive element.

7. A system in accordance with claim 6 wherein each of said conductive elements is provided with a generally centrally located protuberance facing one of said conductive paths through said apertures in said conductive elements to enhance electrical engagement between said conductive element, said conductive member, and said conductive path.

8. A system in accordance with claim 7 wherein a layer of insulating material is disposed intermediate said conductive member and the surface of said member at which said plurality of conductive paths are arranged, said layer of insulating material having a plurality of apertures of a preselected size in axial registration with said apertures in said conductive members and with said conductive elements, said apertures in said layer of insulation material each being of a size sufficient to permit passage therethrough of said protuberance on said conductive element into electrical contact with one of said conductive paths to effect the establishment of a bridging electrical contact between said conductive member and said conductive path when said conductive element is deflected into its over-center position.

9. A system in accordance with claim 6 wherein a generally cylindrical protrusion is provided defining said opposed surface of each of said pushbutton members for selectively engaging said conductive elements in response to actuation of said pushbutton member, said protrusion being in axial alignment with an associated conductive element and having a surface of engagement with said conductive element of a diameter having an area equal to approximately one-third of the surface area of the conductive element in order to cause snap-action deflection of said conductive element thereby effecting positive establishment of the bridging electrical contact in response to actuation of said pushbutton member.

10. A system in accordance with claim 9 wherein said pushbutton members are fabricated, at least in part, of a resilient material adapted to store energy in response to mechanical actuation, said stored energy being transmitted to an associated conductive element upon engagement with said opposed surface of said pushbutton member to produce a positive snap-action deflection of said conductive element intO electrical contact with said conductive member and one of said selected conductive paths.

11. A system in accordance with claim 3 wherein each of said pushbutton members is symbolized in a manner indicative of the electronic function established by the conductive path electrically contacted by said conductive member in response to actuation of said pushbutton member.

12. A system in accordance with claim 11 wherein terminals pads are provided at preselected locations on said support member in electrical contact with said conductive paths and in registration with said conductive elements and at least one semiconductor device is provided having a plurality of circuit elements at a surface thereof adapted to be electrically coupled to selected terminal pads, said circuit elements being adapted to generate selected electrical functions in response to the electrical contact established between said conductive layer and a conductive path upon actuation of a pushbutton member.

13. A system in accordance with claim 12 wherein said conductive layer is adopted to be connected to a source of electrical power so as to effect electrical energization of selected circuit elements of said semiconductor device in response to actuation of a pushbutton member.

14. A system in accordance with claim 13 wherein means are provided for generating an indication of the electrical function represented by actuation of a pushbutton member.

15. A system in accordance with claim 13 wherein said support member for said conductive paths comprises a relatively rigid layer of insulation material, and said terminal pads include enlarged contact portions defined by integral extensions of said conductive path, said semiconductor device is supported on said rigid layer of insulation material adjacent said terminal pads, and said means for generating an electrical function are supported on said rigid layer of insulation material.

16. A pushbutton keyboard system adapted to generate electrical information in response to actuation thereof comprising a support member having a generally planar surface at which a plurality of conductive paths are arranged in a preselected pattern and adapted to transmit electrical information in response to energization thereof, a generally planar sheet of conductive material disposed in spaced, facing relationship with said pattern of conductive paths, said sheet of conductive material including a plurality of contact areas adapted to be selectively electrically coupled to portions of said conductive paths for effecting energization thereof, a plurality of selectively actuatable conductive elements disposed in electrical contact with said contact areas and in selective disengagement with said portions of said conductive paths, said conductive elements being adapted to be individually deflected into a position of engagement with said portions of said conductive paths in response to the application of a preselected deflecting force thereto, thereby effecting an instantaneous bridging electrical contact between said conductive sheet and one of said conductive paths, and means for applying the preselected deflecting force to said conductive elements including a plurality of pushbutton members adapted to be manually actuated to apply the preselected deflecting force to said conductive elements to effect deflection thereof into said position of engagement with said conductive paths, each of said pushbutton members including a force applying surface adjacent an associated conductive element and an exposed surface adapted to be symbolized in a manner indicative of the electrical information to be transmitted by the establishment of electrical contact between said conductive layer and said portion of said conductive path.

17. A system in accordance with claim 16 wherein said conductive elements are each of a generally circular configuration having a convex surface of curvature in facing engagement with the force applying surface of said pushbutton memBer, said convex surface being adapted to be deflected into a concave configuration in response to the application of the preselected force by said force applying surface, thereby establishing the bridging electrical contact between said conductive layer and one of said conductive paths.

18. A system in accordance with claim 16 wherein said conductive element is adapted to be deflected a maximum distance in response to the application of minimum preselected deflecting force.

19. A system in accordance with claim 17 wherein means are provided for supportingly carrying said conductive elements in a manner permitting snap-action deflection of said convex surface into a concave surface while precluding lateral movement of said conductive elements to maintain alignment between said conductive elements and said portions of said conductive paths.

20. A system in accordance with claim 19 wherein said means for supportingly carrying said conductive elements comprises a sheet of insulation material having a plurality of apertures for accommodating said conductive elements and the rims of said conductive elements are maintained in generally sealed relationship with the walls of said apertures to permit deflection of said conductive elements through said apertures in response to actuation by said pushbutton members.

21. A system in accordance with claim 20 wherein said conductive sheet is disposed between said sheet of insulation material carrying said conductive elements and said generally planar surface of said support member, said conductive sheet having a plurality of apertures in axial registration with said apertures in said sheet of insulation material, said apertures in said conductive sheet being of a smaller diameter than said apertures in said sheet of insulation material to define annular contact areas circumscribing said apertures in said sheet of conductive material, said annular contact areas being in engagement with said conductive elements and adapted to permit deflection of the central portion of the conductive elements through said apertures while restraining peripheral movement of said conductive elements.

22. A system in accordance with claim 21 wherein a spacer sheet of insulation material is provided intermediate said conductive sheet and said pattern of conductive paths at said generally planar surface of said support member, said spacer sheet having a plurality of apertures in axial registration with said apertures in said sheet of conductive material and exposing said portions of said conductive paths, said apertures in said spacer sheet being of a diameter equal to or less than the diameter of said apertures in said conductive sheet to maintain said conductive layer electrically insulated from said conductive paths until deflection of said conductive elements is effected to establish the bridging electrical contact between said annular contact areas of said conductive layer and said exposed conductive paths through said apertures in said spacer sheet.

23. A system in accordance with claim 22 wherein said generally conductive elements each include a dimpled protrusion extending toward said conductive paths, said protrusions being of a size less than the size of said apertures in said spacer sheet and being adapted to pass through said apertures in response to deflection of said conductive elements so as to facilitate the establishment of electrical contact with said conductive paths.

24. A system in accordance with claim 23 wherein said support member comprises a sheet of epoxy bonded glass cloth, said conductive paths comprise gold-plated copper, said spacer sheet comprises polyethylene terephthalate resin, said conductive sheet comprises gold-plated brass, said conductive elements comprise gold-plated type 302 stainless steel, said sheet of insulation for carrying said conductive elements comprises epoxy bonded glass cloth and said pushbutton key members comprise an elastomer.

25. A system in accordance with claim 24 wherein said gold-Plated copper conductive paths have a thickness of approximately 0.003 inches, said spacer sheet has a thickness of approximately 0.0045 inches, said gold-plated brass conductive sheet has a thickness of approximately 0.002 inches, said conductive elements have a thickness of approximately 0.004 inches, said sheet of epoxy bonded glass cloth has a thickness of approximately 0.015 inches, and said dimpled protrusion extends approximately 0.004 inches from the surface of said conductive element.

26. A system in accordance with claim 22 wherein a plurality of terminal members are provided at preselected locations adjacent one end of said support layer in electrical contact with said conductive paths, at least one semiconductor device is disposed adjacent said one end of said support layer having a plurality of circuit elements at a surface thereof electrically coupled to selected terminal members, said circuit elements being adapted to perform electrical functions in response to the establishment of electrical contact between said conductive sheet and one of said conductive paths upon deflection of a conductive element, thereby generating the electrical information.

27. A system in accordance with claim 26 wherein said conductive sheet is adapted to be electrically connected to a source of electrical power so as to selectively supply electrical power to said circuit elements upon the establishment of contact between said conductive sheet and said conductive paths through said conductive elements.

28. A system in accordance with claim 27 wherein means are provided supported by said support member electrically coupled to said semiconductor device for generating an indication of the electrical information generated by actuation of one of said pushbutton members.

29. In an electronic calculator;

a pushbutton keyboard system adapted to enter electrical information in response to actuation, said keyboard system including a support member having a generally planar surface at which a plurality of conductive paths are arranged in a preselected pattern and adapted to transmit electrical information in response to energization thereof, a generally planar sheet of conductive material disposed in spaced, facing relationship with said pattern of conductive paths, said sheet of conductive material including a plurality of contact areas adapted to be selectively electrically coupled to portions of said conductive paths for effecting energization thereof, a plurality of selectively actuatable conductive elements disposed in electrical contact with said contact areas and in selective disengagement with said portions of said conductive paths, said conductive elements being adapted to be individually deflected into a position of engagement with said portions of said conductive paths in response to the application of a preselected deflecting force thereto, thereby effecting an instantaneous bridging electrical contact between said conductive sheet and one of said conductive paths, and means for applying the preselected deflecting force to said conductive elements including a plurality of pushbutton members adapted to be manually actuated to apply the preselected deflecting force to said conductive elements to effect deflection thereof into said position of engagement with said conductive paths, each of said pushbutton members including a force applying surface adjacent an associated conductive element and an exposed surface adapted to be symbolized in a manner indicative of the electrical information to be transmitted by the establishment of electrical contact between said conductive layer and said portion of said conductive path;

at least one semiconductor device supported on said support member, said semiconductor device having a plurality of circuit elements at a surface thereof, electrically coupled to said conductive paths, said circuit elements being adapted to generate electrical signals in response to electrical information applied tHereto from said conductive paths upon the establishment of electrical contact between said conductive sheet and said conductive paths; and

indicating means supported by said support member in communication with said semiconductor device for providing an indication of the electrical signals generated in response to information applied to said circuit elements.

30. A multiple switching system comprising in combination:

a plurality of spaced actuating members selectively movable from a first to a second position;

a plurality of contact elements respectively contiguous with said actuating members, each of said elements having a double curved outer surface with a selected area thereof being contiguous to a selected portion of said actuating members, said elements being selectively movable from a first to a second position in response to selective movement of said actuating members;

a support member adjacent to but spaced from said elements and having a plurality of spaced contacts formed thereon respectively positioned adjacent to but spaced from said elements;

an array of conductive areas respectively arranged intermediate said elements and said contacts; and

means for holding said actuating members, said elements, said support member, and said conductive areas in relative position;

whereby when said actuating members are selectively moved from their first to their second position, said respective element is moved from its first to its second position into contact with its respective spaced contact and electrically connects its respective conductive area to its respective spaced contact and when said actuating members are selectively moved from their second to their first position, said respective element automatically moves from its second to its first position out of contact with its respective spaced contact and electrically disconnects its respective conductive area from its respective spaced contact.

31. The multiple switching system of claim 30 wherein each of said contact elements have an over-center second position when a selected portion thereof is subjected to an axial force, said elements automatically returning to their first position when said axial force is removed.

32. The multiple switching system of claim 31 wherein each of said contact elements are segments of an oblique spheroid.