Parallel encoded piezoelectric keyboard switch and array

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:

• 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.

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 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.

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 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.