Mechanical lockout for ultrasonic surgical instrument

An ultrasonic surgical instrument, comprising:

• (a) an ultrasonic transducer;
• (b) a handle assembly supporting the ultrasonic transducer, wherein the handle assembly includes:
• (i) a housing;
• and
• (ii) an ultrasonic blade acoustically coupled with the ultrasonic transducer;
• (c) a clamp arm assembly including a clamp arm;
• and
• (d) at least one lockout member having a body that includes a lockout feature, wherein the lockout feature includes at least one of a curve, a change in angle, a slot, or a proximal extrusion from the body,
• wherein in the locked configuration, the lockout feature prevents rotation of the clamp arm relative to the ultrasonic blade, and
• wherein in the unlocked configuration, the lockout feature allows rotation of the clamp arm relative to the ultrasonic blade.

A method of operating an ultrasonic surgical instrument, wherein the ultrasonic surgical instrument comprises:

• (a) an ultrasonic transducer;
• (b) a handle assembly supporting the ultrasonic transducer, wherein the handle assembly includes:
• (i) a housing;
• and (ii) an ultrasonic blade acoustically coupled with the ultrasonic transducer;
• (c) a clamp arm assembly including a clamp arm;
• and (d) a mechanical lockout assembly configured to switch between at least an unlocked configuration and a locked configuration, wherein the method comprises:
• (a) inhibiting the operator input feature from activating the instrument while in the locked configuration when the handle assembly and the clamp arm assembly are partially coupled together, wherein inhibiting rotation of the clamp arm provides instant feedback to an operator;
• (b) coupling the handle assembly and the clamp arm assembly completely together to disarm the locking assembly;
• and
• (c) activating the instrument using the operator input feature when in the unlocked configuration.