JPS6445009A - Piezoelectric cable for towing - Google Patents

Abstract

PURPOSE:To prevent effects of other than acoustic waves by attaching the terminal surfaces of a pair of piezoelectric elements of different polarization in the diametrical direction coaxially with each other through an insulating plate, connecting inner electrodes with each other, and enclosing insulating oil through flexible electric cores at the center. CONSTITUTION:Insulating oil is filled in flexible tubes for preventing short- circuit of electrodes of lead wires 9a, 9b and cylindrical piezoelectric elements 5a, 5b. If acoustic waves are transmitted from the circumference of the flexible tubes, a signal voltage is produced at the cylindrical piezoelectric elements 5a, 5b of each wave receiving element 3 and it is taken out from the lead wires 9a, 9b. In the meanwhile, if tensile force is applied axially to the left from a core conductor 2, the element 5a is pressed by inertial force in the right inside to an insulating plate 4 to shrink axially and expand diametrically. The element 5b is deformed in the opposite direction. Since polarity of produced charges in the elements 5a, 5b is the same for inner and outer electrodes, potential difference is not produced at the lead wires 9a, 9b wired at outer electrodes 7a, 7b. Produced charges offset each other to deformation in the perpendicular direction to the axis.