Impact transducer keyboard apparatus

Claim 2

Keyboard apparatus comprising: support means; a resilient spring member having an end portion secured to said support means, said spring member being cantilevereD for movement in a plane between first and second positions; actuating means in physical contact with a midpoint of said spring member for urging said spring member between said first and second positions upon physical displacement of said actuating means; hammer means connected to said spring member at a location remote from said support means; a piezoelectric element mounted in relationship to said spring member as to be spaced from said hammer means when said spring member is in its first position and to be struck by said hammer means when said spring member moves from its first position to its second position, said piezoelectric element being adapted to generate an electric signal upon being struck by said hammer means; and latching means associated with said spring member for restraining movement of said spring member from its first position to its second position, said latching means including a magnet member magnetically coupling a region of said spring member so that when the energy stored in said spring member resulting from the urging of said spring member towards its second position exceeds a design level, said latching means releases said spring member so that the energy stored in said spring member causes said spring member to move towards its second position to cause said hammer means to strike said piezoelectric element.

Claim 3

Apparatus according to claim 1 further including electric circuit means connected to said piezoelectric element to receive said generated electric signal, said circuit means including unidirectional conductive means for passing said generated electric signals having a first polarity and for inhibiting passage of said generated electric signals having a second polarity opposite from said first polarity.

Claim 4

Apparatus according to claim 2 wherein said circuit means further includes second unidirectional conductive means for passing said generated electric signals having said second polarity, and a load impedance connected to said second unidrectional conductive means for dissipating electric signals having said second polarity.

Claim 5

Apparatus according to claim 1 wherein said actuating means comprises a key-operable lever arm pivotly rotatable about an axis disposed substantially perpendicular to said plane in which said spring member is moveable, and a cam member connected to said lever arm and having a cam surface in physical contact with said midpoint of said spring member, said cam member urging said spring member between said first and second positions upon pivotal rotation of said lever arm.

Claim 6

Keyboard apparatus having a support and having a plurality of keys and a like plurality of signal generating elements, each responsive to the physical movement of individual ones of said keys, each signal generating element comprising: a resilient spring member having an end portion secured to said support, said spring member being cantilevered for movement in a plane between first and second positions; actuating means in physical contact with a midpoint of said spring member for urging said spring member between said first and second positions upon physical displacement of said actuating means; hammer means connected to said spring member at a location remote from said support; a piezoelectric element mounted in relationship to said spring member as to be spaced from said hammer means when said spring member is in its first position and to be struck by said hammer means when said spring member moves from its first position to its second position, said piezoelectric element being adapted to generate an electric signal upon being struck by said hammer means; latching means associated with said spring member for restraining movement of said spring member from its first position to its second position, said latching means including a magnet member magnetically coupling a region of said spring member so that when the energy stored in said spring member resulting from the urging of said spring member towards its second position exceeds a desIgn level, said latching means releases said spring member so that the energy stored in said spring member causes said spring member to move towards its second position to cause said hammer means to strike said piezoelectric element; and electric circuit means connected to said piezoelectric element to receive said generated electric signal, said circuit means including unidirectional conductive means for passing said generated electric signals having a first polarity and for inhibiting passage of said generated electric signals having a second polarity opposite from said first polarity.

Claim 7

Keyboard apparatus having a support and having a plurality of keys and a like plurality of signal generating elements, each responsive to the physical movement of individual ones of said keys, each signal generating element comprising: a resilient spring member having an end portion secured to said support, said spring member being cantilevered for movement in a plane between first and second positions; actuating means in physical contact with a midpoint of said spring member for urging said spring member between said first and second positions upon physical displacement of said actuating means; hammer means connected to said spring member at a location remote from said support; a piezoelectric element mounted in relationship to said spring member as to be spaced from said hammer means when said spring member is in its first position and to be struck by said hammer means when said spring member moves from its first position to its second position, said piezoelectric element being adapted to generate an electric signal upon being struck by said hammer means; latching means associated with said spring member for restraining movement of said spring member from its first position to its second position, said latching means including a magnet member magnetically coupling a region of said spring member so that when the energy stored in said spring member resulting from the urging of said spring member towards its second position exceeds a desIgn level, said latching means releases said spring member so that the energy stored in said spring member causes said spring member to move towards its second position to cause said hammer means to strike said piezoelectric element; and electric circuit means connected to said piezoelectric element to receive said generated electric signal, said circuit means including unidirectional conductive means for passing said generated electric signals having a first polarity and for inhibiting passage of said generated electric signals having a second polarity opposite from said first polarity.

Claim 8

Apparatus according to claim 5 further including second unidirectional conductive means connected to all of said piezoelectric elements for passing generated electric signals having said second polarity, and a load impedance connected to said second unidirectional conductive means for dissipating electric signals having said second polarity.