Abstract: Resilient attachment members interconnect a pair of flat plates of a movement detector pad and are preferably disposed in the corners of these flat plates. A piezoelectric transducer is disposed centrally between the plates to generate signals when the plates move with respect to one another. In one embodiment the resilient attachment members each have a connector pin which is connected to one of the plates and extends into a pin receiving hollow node formed in the other plates and projecting above an inner surface of the other plate. The end of the connector pin has lateral projections to engage within the node when both plates are spaced apart a predetermined distance by the pressure of helical springs which are disposed about each pin and its associated node. During movement of the pin within the node the pin is in substantially friction free movement whereby not to corrupt the movement signal generated by the piezoelectric crystal.

Abstract: Resilient attachment members interconnect a pair of flat plates of a movement detector pad and are preferably disposed in the corners of these flat plates. A piezoelectric transducer is disposed centrally between the plates to generate signals when the plates move with respect to one another. In one embodiment the resilient attachment members each have a connector pin which is connected to one of the plates and extends into a pin receiving hollow node formed in the other plates and projecting above an inner surface of the other plate. The end of the connector pin has lateral projections to engage within the node when both plates are spaced apart a predetermined distance by the pressure of helical springs which are disposed about each pin and its associated node. During movement of the pin within the node the pin is in substantially friction free movement whereby not to corrupt the movement signal generated by the piezoelectric crystal.