Electronic musical instrument keying assembly providing a minimum of electrical noise

Claim 2

In an electronic musical instrument which includes a manually operable switch for connecting an amplifier input to a signal source that has first and second terminals, and in which the switch includes a first sheet-like switch member that is easily deformable into contact with another switch element, and in which the first sheet-like switch member is connected to the amplifier while the switch element is connected to the second terminal of the signal source, the improvement comprising: a second sheet-like member of easily deformable insulative material fixed facewise to said first sheet-like switch member and a third sheet-like shielding member of easily deformable electrically conductive material fixed facewise to said second sheet-like member on a face thereof opposite said sheet-like switch member; and means coupled to said third sheet-like shielding member and to said first signal source terminal for preventing rapid changes in their potential with respect to each other, whereby to prevent vibration of the first switch member with respect to its shield.

Claim 3

The improvement described in claim 1 wherein: said musical instrument includes a plurality of additional switch elements arranged in a row; and said first sheet-like switch member and said second and third sheet-like members are of elastomeric material and are held in a taut condition in extension along said row of switch elements.

Claim 4

The improvement described in claim 1 wherein: said means for preventing rapid changes in potential connects said shielding member and said first source terminal together to maintain them at the same potential.

Claim 5

An electronic musical instruement switch comprising: a support; an electrically conductive member mounted on said support, said member having a convex contact portion facing away from said support; a contact strip of electrically conductive and easily stretched and deformed elastic material; means for supporting said contact strip in a taut condition so it is spaced from said convex contact portion but can be deflected against it; manually operable means for deforming said contact strip against said convex contact portion; a strip of elastic insulative material fixed facewise to a face of said contact strip which lies opposite the face thereof which is nearest said conductive member; a second strip of elastic electrically conductive material fixed facewise to a face of said strip of insulative material which is opposite said first named strip of conductive material; a signal generator having a grounded first terminal and having a second terminal coupled to said conductive member; an amplifier; means for coupling the input of said amPlifier to said first named strip of conductive material, and means for grounding said second strip of conductive material.

Claim 6

An electronic musical instruement switch comprising: a support; an electrically conductive member mounted on said support, said member having a convex contact portion facing away from said support; a contact strip of electrically conductive and easily stretched and deformed elastic material; means for supporting said contact strip in a taut condition so it is spaced from said convex contact portion but can be deflected against it; manually operable means for deforming said contact strip against said convex contact portion; a strip of elastic insulative material fixed facewise to a face of said contact strip which lies opposite the face thereof which is nearest said conductive member; a second strip of elastic electrically conductive material fixed facewise to a face of said strip of insulative material which is opposite said first named strip of conductive material; a signal generator having a grounded first terminal and having a second terminal coupled to said conductive member; an amplifier; means for coupling the input of said amPlifier to said first named strip of conductive material, and means for grounding said second strip of conductive material.

Claim 7

An electronic musical instrument switch comprising: a support; an electrically conductive contact member mounted on said support; a sandwich which includes a first strip of elastic conductive material, a second strip of elastic insulative material disposed facewise against said first strip, and a third strip of elastic conductive material disposed facewise against said second strip on a face thereof which is opposite said first strip, the opposite faces of said second strip respectively fixed to said first and third strips to maintain said first and third strips at a constant distance; means for supporting said sandwich so that said first strip thereof is spaced from said contact member but can deflect against it; manually operable key means for selectively pressing against said third strip to cause said first strip to deflect against said contact member; a signal source having first and second terminals; means for coupling said second terminal of said signal source to said contact member; an amplifier; means for coupling the input of said amplifier to said first strip of said sandwich; and means electrically coupled to said first terminal of said signal generator and said third strip of said sandwich for maintaining said first terminal at a constant potential with respect to said third strip.

Claim 8

An electronic musical instrument switch comprising: a support; an electrically conductive contact member mounted on said support; a sandwich which includes a first strip of elastic conductive material, a second strip of elastic insulative material disposed facewise against said first strip, and a third strip of elastic conductive material disposed facewise against said second strip on a face thereof which is opposite said first strip, the opposite faces of said second strip respectively fixed to said first and third strips to maintain said first and third strips at a constant distance; means for supporting said sandwich so that said first strip thereof is spaced from said contact member but can deflect against it; manually operable key means for selectively pressing against said third strip to cause said first strip to deflect against said contact member; a signal source having first and second terminals; means for coupling said second terminal of said signal source to said contact member; an amplifier; means for coupling the input of said amplifier to said first strip of said sandwich; and means electrically coupled to said first terminal of said signal generator and said third strip of said sandwich for maintaining said first terminal at a constant potential with respect to said third strip.