Keyboard integrated pointing device

• US 5,499,041 A
• Filed: 10/13/1994
• Issued: 03/12/1996
• Est. Priority Date: 07/24/1990
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Incontrol Solutions, Inc.
• Inventors: Brandenburg, Eric L., Straayer, David H., Franz, Patrick J.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Saras, Steven J.
• Application Number:
  US08/322,956
• Time in Patent Office: 516 Days
• Field of Search: 345/156, 345/157, 345/168, 345/172, 345/184, 200/5 A, 200/6 A, 200/5 R, 200/511, 200/513, 338/99, 338/114, 341/27, 341/34
• US Class Current: 345/174
• CPC Class Codes: G05G 2009/04762 Force transducer, e.g. strain gauge
• CPC Class Codes: G05G 9/047 the controlling member being movable by hand about orthogonal axes, e.g. joysticks for switches H01H25/04
• CPC Class Codes: G06F 3/0213 Arrangements providing an integrated pointing device in a keyboard, e.g. trackball, mini-joystick for pointing devices integrated in a laptop computer G06F1/169; joysticks G05G9/047; constructional details of pointing devices G06F3/033
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: H01H 13/70 having a plurality of operating members associated with different sets of contacts, e.g. keyboard mounting together a plurality of independent switches H02B
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 13/807 characterised by the spatial arrangement of the contact sites, e.g. superimposed sites
• CPC Class Codes: H01H 2003/0293 with an integrated touch switch
• CPC Class Codes: H01H 2201/02 Piezo element
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: H01H 2221/012 Joy stick type
• CPC Class Codes: H01H 2225/018 Consecutive operations
• CPC Class Codes: H01H 2225/03 Different type of switches
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such
• CPC Class Codes: H01H 2239/052 Strain gauge

Abstract

A keyswitch-integrated pointing assembly in which a plurality of substantially planar force sensing elements are disposed on a planar surface adjacent a keyswitch on a keyboard. The keyswitch includes a plunger which extends downwardly from a key cap for actuating a switch at the lower end of vertical key cap travel. The key cap engages an indexing surface when fully depressed which transmits force applied to the key cap to the force sensing elements. The force sensing elements are sandwiched between a pair of opposing plates thereby biasing the elements into a substantially linear operating region when no force is applied to the key cap.

Claims

1. A pointing device for cursor control comprising:

an actuator assembly having an elongate plunger along a central vertical axis and having at one end a plurality of co-planar actuator surfaces arrayed initially in a horizontal plane;

a generally flat, rigid base located opposite the actuator surfaces;

generally planar force sensing means sandwiched between the base plate and the actuator surfaces, the force sensing means including at least three force sensing elements symmetrically disposed about the central vertical axis of the plunger and substantially registered with the actuator surfaces, each force sensing element responsive to a generally perpendicular force and each having a respective near-linear region of operation;

pre-load means including a compressed resiliently elastic member for urging the actuator assembly and the force sensing means together, thereby maintaining the actuator surfaces in constant contact with all of the force sensing elements to provide a common pre-load force on each force sensing element;

the pre-load means arranged to provide adequate compression so as to drive each of the force sensing elements into its respective near-linear region of operation;

fastener means connecting the actuator means and base plate together, said fastener means arranged to allow slight lateral movement of the actuator surfaces in a horizontal plane and corresponding tilting of the co-planar actuator surfaces from the initial horizontal position in response to a lateral external force imparted to the actuator assembly so as to impart an increasing force on at least one of the force sensing elements adjacent a downwardly tilting actuator surface and a decreasing force on at least one other of the force sensing elements adjacent an upwardly tilting actuator surface, thereby providing a differential signal to increase sensitivity of the pointing device.

2. A pointing device for cursor control according to claim 1 wherein the pointing device is disposed in a computer keyboard that includes a rubber dome sheet, and the device is arranged so that the rubber dome sheet extends between the actuator surfaces and the corresponding force sensing elements for disbursing forces applied through the actuator surfaces to the force sensing elements.

3. A pointing device for cursor control according to claim 1 further comprising a single, flat, rigid backup plate, disposed in parallel to and below the base plate;

and wherein the preload elastic member extends between the backup plate and the base plate.

4. A pointing device for cursor control according to claim 1 further comprising a fixed, rigid top plate, extending over the actuator assembly;

and wherein the preload elastic member extends between the top plate and the actuator assembly.

5. A computer keyboard for typing and cursor control having a plurality of keys for typing mounted on a reference plate, at least one key comprising:

a typing switch contact located on the reference plate and linked to a designated character;

a plurality of force sensing elements symmetrically disposed about and operated independent from the typing switch contact;

an actuator assembly including an elongate plunger moveable in a vertical direction and having a contacting end registered over and biased vertically away from the typing switch contact and a keycap engaged with the plunger and capable of transmitting to the plunger a downward vertical force imparted to the keycap by a user thereby contacting the plunger with the typing switch contact, the actuator further including protruding actuator surfaces each disposed in constant contact with a corresponding one of the force sensing elements under a common pre-load force and capable of asymmetrically transmitting a lateral force imparted to the keycap to the symmetrically disposed force sensing elements;

means for maintaining the common pre-load force applied to all of the force sensing elements so that the force sensors do not exhibit a null zone in operation;

and means responsive to a non-vertical external force applied to the actuator for effecting a decreasing resistance in at least one of the force sensors and an increasing resistance in at least one other of the force sensors, thereby providing a differential signal that increases sensitivity of the pointing device.