Ultrasonic surgical instrument with transducer locking feature

A surgical instrument, comprising:

• (a) an end effector;
• (b) a shaft assembly extending proximally from the end effector along a longitudinal axis, wherein the shaft assembly includes:
• (i) an acoustic waveguide extending along the longitudinal axis;
• (ii) a knob operatively connected to the acoustic waveguide, wherein the knob is configured to be selectively rotated and thereby rotate the acoustic waveguide;
• and
• (c) an integral torque wrench positioned internally to the knob and connected to the knob via a releasable coupling such that the integral torque wrench is configured to rotate with the knob, wherein the releasable coupling is configured to transmit torque from the integral torque wrench to the knob up to a predetermined torque, and wherein the releasable coupling is configured to release the knob as the transmitted torque exceeds the predetermined torque such that the integral torque wrench rotatably slips relative to the knob for inhibiting the transmission of torque through the knob from exceeding the predetermined torque while coupling the acoustic waveguide to an ultrasonic transducer assembly, wherein the integral torque wrench includes:
• (i) a body,
• (ii) a compressible member, and
• (iii) a cam, wherein one of the compressible member and the cam extend from the body and the other of the compressible member and the cam extend from the knob, wherein the compressible member is engaged with the cam to transmit torque therethrough, wherein the cam is configured to compress the compressible member as the torque being transmitted therethrough is increased, and wherein the compressible member is configured to slip from the cam to disengage the compressible member from the cam as the torque being transmitted therethrough exceeds the predetermined torque.

A surgical instrument, comprising:

• (a) an instrument body;
• (b) an ultrasonic transducer assembly rotatably mounted along a longitudinal axis within the instrument body such that the ultrasonic transducer assembly is configured to selectively rotate about the longitudinal axis;
• (c) an acoustic waveguide configured to threadably couple with the ultrasonic transducer assembly;
• and
• (d) an integral torque indicator, including:
• (i) a first member extending from the acoustic waveguide, and
• (ii) a second member extending from the ultrasonic transducer assembly,
• wherein the first and second members are positioned such that the first member is configured to engage the second member as the acoustic waveguide is threadably coupled with the ultrasonic transducer assembly with a predetermined amount of torque, and wherein the first and second members are configured to engage each other to thereby generate a signal indicative of the predetermined amount of torque for a user.