Keyboard switch having a deformable membrane formed of cellular urethane

A keyboard for a musical instrument having a plurality of elongated key assemblies with each key assembly comprising

• a plurality of elongated keys each having a rearwardly extending actuating means with an upper and a lower nonresilient actuator,
• a first and a second switch, each having a substrate with at least one fixed contact thereon, a deformable membrane having a movable electrically conductive coating disposed directly thereon, said coating positioned adjacent said fixed contact and adapted for moving into and out of electrical connection with said fixed contact for completing a circuit therebetween, means for mounting said first switch to be engaged by the lower actuator when the key is in its lower position and means for mounting said second switch to be engaged by the upper actuator when the key is in its upper position, the key being maintained normally engaging the deformable membrane of said first switch to maintain said first switch normally closed, and
• said deformable membrane being formed of mechanically frothed open cell cellular urethane foam whereby upon actuation the deformable membrane distributes and absorbs the actuation force without damage to the keyboard switches and upon release the deformable membrane springs back to its undeformed shape retracting the movable coating from the fixed contact.