Patent ID: 8097011

Claim:
A surgical treatment apparatus comprising: a first unit including a first vibration transmission member extended in an axial direction, including an end portion, and configured to transmit ultrasonic vibration, and a first holding member holding the first vibration transmission member; a second unit including a second vibration transmission member extended in an axial direction, including an end portion, and configured to transmit the ultrasonic vibration, a second holding member holding the second vibration transmission member movable in the axial direction of the second vibration transmission member, and an elastic member provided between the second vibration transmission member and the second holding member, configured to be deformed in accordance with a relative arrangement of the second vibration transmission member and the second holding member with respect to the axial direction of the second vibration transmission member to give the second vibration transmission member an elastic force in the axial direction; and a cam mechanism including an actuating receiving portion provided to one of the first holding member and the second holding member, spirally extended around the axial direction, and including a coupling position, and an actuating portion provided to other of the first holding member and the second holding member and configured to be moved along the actuation receiving portion and arranged at the coupling position to couple the first unit and the second unit with each other, arrange the first vibration transmission member and the second vibration transmission member coaxially to abut the end portion of the first vibration transmission member and the end portion of the second vibration transmission member against each other, and adjust a relative arrangement of the first holding member and the second holding member with respect to a coaxial direction to be constant to adjust a deformation amount of the elastic member to be constant, and wherein the cam mechanism changes a pressure angle with respect to a rotation angle such that a rotating operation force amount is fixed in a rotating operation of relatively moving the first holding member and the second holding member in the coaxial direction against the elastic force of the elastic member.