Patent ID: 8529592

Claim:
An ultrasonic treatment instrument comprising: a piezoelectric element assembly which includes a plurality of piezoelectric elements which are aligned with a longitudinal direction, which includes one end and the other end and which is configured to generate ultrasonic vibration; a probe which includes a base end connected to the one end of the piezoelectric element assembly and a tip end extending from the proximal end along the longitudinal direction and which is configured to transmit the ultrasonic vibration from the base end to the tip end and treat a body tissue by the ultrasonic vibration; a backing plate which includes a distal end connected to the other end of the piezoelectric element assembly and a proximal end extending from the distal end of the backing plate along the longitudinal direction; an electrode assembly which is configured to extend from the distal end to the proximal end of the backing plate, which includes a plurality of electrodes respectively clamped between the piezoelectric elements and which is configured to electrify the piezoelectric elements and generate the ultrasonic vibration; a cylinder which is connected to the base end of the probe, which includes a toe end and a heel end and which is configured to locate the piezoelectric element assembly, the backing plate and the electrode assembly therein; and a cylindrical inner cover which includes an inner diameter larger than the backing plate and an outer diameter smaller than the cylinder; wherein: the inner cover is disposed between the backing plate and the electrode assembly, and the electrode assembly is disposed between the cylinder and the inner cover, wherein the cylinder includes a coil shaft having a diameter smaller than that of the cylinder and connected to the heel end of the cylinder; and the backing plate includes a taper with a smooth inclined face at a connecting portion with the coil shaft.