Parallel encoded piezoelectric keyboard switch and array
First Claim
1. A keyboard switch for transducing a mechanical depression force applied to a key member into electrical signals representing that key member, said switch comprising:
- a housing;
an actuator member movable depressionally and elevationally in said housing in a first direction in response to depression and elevation, respectively, of said key member;
a snap action spring member which snaps between first and second stable positions generally along said first direction;
means linking said actuator member to said snap action spring member for snapping said snap action spring member from said first position to said second position in response to a predetermined depression of said actuator member from a rest position, and for snapping said spring member from said second position to said first position in response to a predetermined elevation position of said actuator;
a plurality of spaced piezoelectric transducer means for providing respective electrical signals when subjected to mechanical stress;
a common impact-receiving member secured to each of said transducer members for transmitting to said transducer members mechanical forces which are applied to said impact-receiving member;
support means positionally fixed in said housing and disposed in contact with each of said transducer members such that said transducer members are disposed between said support means and said impact-receiving means;
percussion applicator means secured to said snap action spring members such that said percussion applicator means forcefully percussively impacts directly against said impact-receiving member to mechanically stress said transducer members against said support means when said snap action spring member snaps from said first position to said second position; and
return bias means for continuously urging said actuator in a direction to elevate said actuator member beyond said predetermined elevation and toward said rest position.
3 Assignments
0 Petitions
Accused Products
Abstract
A keyboard switch includes a plurality of spaced piezoelectric transducers secured to a common strike plate which is selectively impacted to actuate all of the transducers in response to switch actuation. The switch includes a snap action spring member carrying an impact member which impacts the strike plate as the spring member snaps to its actuated state when the switch is depressed . The spring member causes the impact member to maintain a compressive force against the strike plate, maintaining the transducers actuated while the key remains depressed and for a short interval after the key is released. An array of such switches on a keyboard is disposed over a plurality of parallel data lines which electrically contact one or more transducers at each switch in accordance with a switch indentification code. The parallel binary number appearing on the lines is received by processing circuitry which identifies each depressed key by its code. By maintaining compressive forces on the transducers, the system facilitates character processing and generation of certain specialized character functions.
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Citations
25 Claims
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1. A keyboard switch for transducing a mechanical depression force applied to a key member into electrical signals representing that key member, said switch comprising:
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a housing; an actuator member movable depressionally and elevationally in said housing in a first direction in response to depression and elevation, respectively, of said key member; a snap action spring member which snaps between first and second stable positions generally along said first direction; means linking said actuator member to said snap action spring member for snapping said snap action spring member from said first position to said second position in response to a predetermined depression of said actuator member from a rest position, and for snapping said spring member from said second position to said first position in response to a predetermined elevation position of said actuator; a plurality of spaced piezoelectric transducer means for providing respective electrical signals when subjected to mechanical stress; a common impact-receiving member secured to each of said transducer members for transmitting to said transducer members mechanical forces which are applied to said impact-receiving member; support means positionally fixed in said housing and disposed in contact with each of said transducer members such that said transducer members are disposed between said support means and said impact-receiving means; percussion applicator means secured to said snap action spring members such that said percussion applicator means forcefully percussively impacts directly against said impact-receiving member to mechanically stress said transducer members against said support means when said snap action spring member snaps from said first position to said second position; and return bias means for continuously urging said actuator in a direction to elevate said actuator member beyond said predetermined elevation and toward said rest position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. In an electrical keyboard assembly of the type wherein individual keyboard switches in an array are selectively actuable to apply an n-bit binary number in parallel on n respective common data lines, a processing circuit for processing said n-bit binary numbers comprising:
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n resettable latch means, each connected to a respective data line to receive signals appearing on that line and provide a data signal representing the binary state of the received signals; n clocked register means, each responsive to application of a gating signal thereto for entering therein the data signal provided by a respective latch means; and timer means responsive to application of a trigger signal thereto for providing said gating signal after elapse of a first predetermined time interval following application of said trigger signal, and for providing a reset signal to reset each of said latch means after elapse of a second predetermined time interval following application of said trigger signal, said second predetermined time interval being longer than said first predetermined time interval. - View Dependent Claims (20, 21)
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22. A keyboard switch for transducing a mechanical depression force applied to a key member into electrical signals representing that key member, said switch comprising;
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a housing; an actuator member movable depressionally and elevationally in said housing in a first direction in response to depression and elevation, respectively, of said key member; a plurality of spaced piezoelectric transducer means for providing respective electrical signals when subjected to mechanical stress; a common impact-receiving member secured to each of said transducer members for transmitting to said transducer members mechanical forces which are applied to said impact-receiving member; support means positionally fixed in said housing and disposed in contact with each of said transducer members such that said transducer members are disposed between said support means and said impact-receiving means; percussion applicator means actuable by said actuator member for forcefully impacting against said impact-receiving member to substantially equally mechanically stress said transducer members; and an assembly comprising a plurality of said keyboard switches positionally arranged in an array of columns and rows, said assembly further comprising; a plurality of spaced parallel electrically conductive tracks, comprising part of said suport means in each of said plurality of keyboard switches, extending in respective generally serpentine paths which pass adjacent each switch, each track being in electrical contact with a respective transducer member at selected keyboard switches; electrically insulative means disposed between preselected transducer members at each of said keyboard switches and their respective adjacent track such that a different combination of transducer members contacts the conductive tracks at each keyboard switch to define a unique combination of such contacts identifying that keyboard switch; and circuit means connected to said tracks for detecting electrical signals applied thereto from said transducer members. - View Dependent Claims (23, 24)
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25. A keyboard switch for transducing a mechanical depression force applied to a key member into electrical signals representing that key member, said switch comprising;
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a housing; an actuator member movable depressionally and elevationally in said housing in a first direction in response to depression and elevation, respectively, of said key member; a plurality of spaced piezoelectric transducer means for providing respective electrical signals when subjected to mechanical stress; a common impact-receiving member secured to each of said transducer members for transmitting to said transducer members mechanical forces which are applied to said impact-receiving member; support means positionally fixed in said housing and disposed in contact with each of said transducer members such that said transducer members are disposed between said support means and said impact-receiving means; percussion applicator means actuable by said actuator member for forcefully impacting against said impact-receiving member to substantially equally mechanically stress said transducer members; and wherein said support means comprises a plurality of electrically conductive members, each being electrically coupled to a respective piezoelectric transducer member to receive respective electrical signals from said transducer members.
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Specification