Touch responsive keying unit for electronic musical instruments

Claim 3

Apparatus as set forth in claim 1 wherein: said stationary plate comprises an electrically conductive material sandwiched between two sheets of insulating flexible material; and said movable plate comprises an electrically conductive U-shaped portion forming a receiving channel through which said stationary plate is positioned, whereby in the rest position said movable plate does not substantially overlap the electrically conductive material of said stationary plate but does overlap in proportion to the force applied to one of said keys.

Claim 4

Apparatus as set forth in claim 1 wherein said linking means comprises: a beam member for contacting said key; an L-shaped drive member pivotally connected to said beam member; a rod for contacting said drive member during its downward movement and causing it to rotate counterclockwise about said pivot connection; and a receiving block with a curved surface for engagement with said drive member.

Claim 5

Apparatus as set forth in claim 3 wherein said receiving block is positioned so that said curved surface slopes upward from the horizontal and said drive means engages said surface.

Claim 6

Apparatus as set forth in claim 4 wherein said receiving block is connected to said movable capacitor plate whereby the downward movement of the receiving block causes the movable plate to travel toward a momentary overlap condition with said stationary plate.

Claim 7

Apparatus set forth in claim 1 wherein: said movable plate and said stationary plate are in a non-overlapping rest position prior to key depression; and, said velocity transducer further comprises restraining means for returning said movable plate to said rest position after said temporary overlap regardless of maintained key depression by the instrument player.

Claim 8

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for providing an AC signal; a velocity transducer connected to said source means and to said keys for passing said AC signal in proportion to the force applied to one of said keys during the time interval taken to depress one of said keys; and, circuit means responsive to said passed AC signal and comprising: input impedance means responsive to said passed AC signal for varying the value of impedance; a voltage source connected to said input impedance means; and, storage means responsive to said input impedance means for receiving a proportion of said voltage and producing a voltage discharge envelope to control said tone circuit.

Claim 9

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for providing an AC signal; a velocity transducer connected to said source means and to said keys for passing said AC signal in proportion to the force applied to one of said keys during the time interval taken to depress one of said keys; and, circuit means responsive to said passed AC signal and comprising: input impedance means responsive to said passed AC signal for varying the value of impedance; a voltage source connected to said input impedance means; and, storage means responsive to said input impedance means for receiving a proportion of said voltage and producing a voltage discharge envelope to control said tone circuit.

Claim 10

Apparatus as set forth in claim 7 further comprising: a keyboard contact for closing each time one of said keys is depressed and connected to said voltage source; a percussive circuit responsive to the closure of said keyboard contact and connected in parallel to said storage means for producing a voltage pulse, whereby said percussive circuit produces said voltage pulse each time one of said keys is depressed regardless of the force applied.

Claim 11

Apparatus as set forth in claim 8 further comprising: a dual slope discharge circuit connected in parallel to said storage means for dissipating the voltage stored on said storage means.

Claim 12

Apparatus as set forth in claim 9 wherein said dual slope discharge circuit comprises in parallel: a rapid discharge circuit including in series a blocking non-linear circuit element and a first resistor and connected to said keyboard contact; and a slow discharge circuit including a second resistor wherein the resistance value of said second resistor is much greater than the resistance value of said first resistor.

Claim 13

Apparatus as set forth in claim 10 wherein said storage means discharges through said slow discharge circuit when said keyboard contact remains closed and discharges through said rapid discharge circuit when said keyboard contact is released.

Claim 14

Apparatus as set forth in claim 10 wherein the level of the voltage signal discharge envelope is proportioned to the force applied to one of said keys when said voltage signal proportional to said input impedance is higher than said voltage pulse produced from said percussive circuit.

Claim 15

Apparatus as set forth in claim 12 wherein said storage means discharges through said rapid discharge circuit when said keyboard contact is released and discharges partially through said rapid discharge circuit then partially through said slow discharge circuit when said keyboard contact remains closed.

Claim 16

Apparatus as set forth in claim 10 further comprising: a sustain circuit connected to said slow discharge circuit and to said rapid discharge circuit.

Claim 17

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for generating an AC signal; touch responsive means connected to said keys and said source means and comprising: linking means for transferring the force applied to one of said keys during the time interval taken to depress one of said keys; and, capacitor means responsive to said linking means for momentarily varying the value of capacitance in proportion to said force and responsive to said source means for passing said AC signal in proportion to said value of capacitance; said capacitor means comprising: a stationary plate comprising an electrically conductive material sandwiched between two sheets of insulating flexible material; a movable plate comprising an electrically conductive U-shaped portion forming a receiving channel through which said stationary plate is positioned, said electrically conductive material of said stationary plate and said electrically conductive portion of said movable plate are in a nonoverlapping rest position prior to key depression; and, said electrically conductive portion of said movable plate responsive to said linking means overlaps said electrically conductive material of said stationary plate in proportion to the depressive force applied to one of said keys causing the value of the capacitance to increase with the degree of electrically conductive plate area overlap; and, circuit means responsive to said passed AC signal for producing a voltage signal envelope to control said tone circuit.

Claim 18

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for generating an AC signal; touch responsive means connected to said keys and said source means and comprising: linking means for transferring the force applied to one of said keys during the time interval taken to depress one of said keys; and, capacitor means responsive to said linking means for momentarily varying the value of capacitance in proportion to said force and responsive to said source means for passing said AC signal in proportion to said value of capacitance; said capacitor means comprising: a stationary plate comprising an electrically conductive material sandwiched between two sheets of insulating flexible material; a movable plate comprising an electrically conductive U-shaped portion forming a receiving channel through which said stationary plate is positioned, said electrically conductive material of said stationary plate and said electrically conductive portion of said movable plate are in a nonoverlapping rest position prior to key depression; and, said electrically conductive portion of said movable plate responsive to said linking means overlaps said electrically conductive material of said stationary plate in proportion to the depressive force applied to one of said keys causing the value of the capacitance to increase with the degree of electrically conductive plate area overlap; and, circuit means responsive to said passed AC signal for producing a voltage signal envelope to control said tone circuit.

Claim 19

Apparatus as set forth in claim 15 wherein said linking means comprises: a beam member for contacting said key, an L-shaped drive member pivotally connected to said beam member, a rod for contacting said drive member during its downward movement and causing it to rotate counterclockwise about said pivot connection, a receiving block having curved surface for engagement with said drive member and connected to said movable plate, said receiving block positioned so that said curved surface slopes upward from the horizontal whereby the downward movement of said receiving block causes said movable plate to travel toward an overlap condition with said stationary plate; and restraining means for returning said movable plate to the rest position.

Claim 20

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for generating an AC signal; touch responsive means connected to said keys and said source means and comprising: linking means for transferring the force applied to one of said keys during the time interval taken to depress one of said keys; and, capacitor means responsive to said linking means for momentarily varying the value of capacitance in proportion to said force and responsive to said source means for passing said AC signal in proportion to said value of capacitance; and, circuit means responsive to said passed AC signal and comprising: input impedance means responsive to said passed AC signal for varying the value of impedance; a voltage source connected to said input impedance means; and, storage means responsive to said input impedance means for receiving a proportion of said voltage and producing a voltage discharge envelope to contol said tone circuit.

Claim 21

Apparatus for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: source means for generating an AC signal; touch responsive means connected to said keys and said source means and comprising: linking means for transferring the force applied to one of said keys during the time interval taken to depress one of said keys; and, capacitor means responsive to said linking means for momentarily varying the value of capacitance in proportion to said force and responsive to said source means for passing said AC signal in proportion to said value of capacitance; and, circuit means responsive to said passed AC signal and comprising: input impedance means responsive to said passed AC signal for varying the value of impedance; a voltage source connected to said input impedance means; and, storage means responsive to said input impedance means for receiving a proportion of said voltage and producing a voltage discharge envelope to contol said tone circuit.

Claim 22

Apparatus as set forth in claim 17 further comprising: a keyboard contact for closing each time one of said keys is depressed and connected to said voltage source; a percussive circuit responsive to the closure of said keyboard contact and connected in parallel to said storage means for producing a voltage pulse, whereby said percussive circuit produces said voltage pulse each time one of said keys is depressed regardless of the force applied.

Claim 23

Apparatus as set forth in claim 18 further comprising a dual slope discharge circuit connected in parallel to said storage means for discharging the voltage stored on said storage means and comprises in parallel: a rapid discharge circuit including in series a blocking non-linear circuit element and a first resistor and connected to said keyboard contact; and a slow discharge circuit including a second resistor wherein the resistance value of said second resistor is much greater than the resistance value of said first resistor.

Claim 24

Apparatus as set forth in claim 19 wherein said storage means discharges through said slow discharge circuit when said keyboard contact remains closed and discharges through said rapid discharge circuit when said keyboard contact is released.

Claim 25

Apparatus as set forth in claim 20 wherein: the level of the voltage signal discharge envelope is proportioned to the force applied to one of said keys when said voltage signal proportional to said input impedance is higher than said voltage pulse produced from said percussive circuit; and said storage means discharges through said rapid discharge circuit when said keyboard contact is released and discharges partially through said rapid discharge circuit then partially through said slow discharge circuit when said keyboard contact remains closed.

Claim 26

Apparatus as set forth in claim 19 further comprising: a sustain circuit connected to said slow discharge circuit and to said rapid discharge circuit.

Claim 27

A circuit for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: input means for receiving an input signal proportional to the force applied to one of said keys; a keyboard contact for closing each time one of said keys is depressed; a percussive circuit responsive to said closure of said keyboard contact for producing a voltage pulse independent of said force applied to said keys; storage means responsive to said input means and said percussive circuit for producing a voltage discharge envelope to control said tone circuit; said percussive circuit connected in parallel to said storage means; and, a dual slope discharge circuit connected in parallel to said storage means and including in parallel; a rapid discharge circuit including in series a blocking non-linear circuit element and a first resistor and connected to said keyboard contact; and, a slow discharge circuit including a second resistor wherein the resistance value of said second resistor is much greater than the resistance value of said first resistor.

Claim 28

A circuit for use in an electronic musical instrument having a plurality of juxtapositioned keys forming a keyboard and a tone circuit to produce a different tone signal output corresponding to the depression of each of said keys comprising: input means for receiving an input signal proportional to the force applied to one of said keys; a keyboard contact for closing each time one of said keys is depressed; a percussive circuit responsive to said closure of said keyboard contact for producing a voltage pulse independent of said force applied to said keys; storage means responsive to said input means and said percussive circuit for producing a voltage discharge envelope to control said tone circuit; said percussive circuit connected in parallel to said storage means; and, a dual slope discharge circuit connected in parallel to said storage means and including in parallel; a rapid discharge circuit including in series a blocking non-linear circuit element and a first resistor and connected to said keyboard contact; and, a slow discharge circuit including a second resistor wherein the resistance value of said second resistor is much greater than the resistance value of said first resistor.

Claim 29

A circuit as set forth in claim 23 wherein the level of said voltage discharge envelope is proportional to the force applied to one of said keys when said input signal is larger than said voltage pulse produced from said percussive circuit.

Claim 30

A circuit as set forth in claim 24 wherein said storage means discharges through said rapid discharge circuit when said keyboard contact is released and discharges partially through said rapid discharge circuit then partially through said slow discharge circuit when said keyboard contact remains closed.

Claim 31

A circuit as set forth in claim 23 further comprising: a sustain circuit connected to said slow discharge circuit and to said rapid discharge circuit.