Active braking electrical surgical instrument and method for braking such an instrument

An electrically powered surgical instrument, comprising:

• a surgical end effector having at least one actuation assembly to effect a surgical procedure when actuated;
• a handle mechanically coupled with the end effector and having a shell;
• an electric motor disposed within the shell and having:
• power terminals at which the motor can be supplied with power;
• and
• a drive train operatively coupled to the at least one actuation assembly to actuate the at least one actuation assembly when the motor is supplied with power;
• a power supply switch at the handle that selectively controls a supply of power to the motor, the power supply switch having:
• a break-before-make switching configuration;
• a power-supplying state in which power is supplied to the motor;
• and
• a power-removed state in which power is not supplied to the motor;
• and
• a post-termination braking circuit having the power supply switch as a component thereof, the post-termination braking circuit electrically short-circuiting the power terminals of the motor with the power-removed state of the power supply switch.

A method for post-termination braking of an electrical motor in an electrically powered surgical instrument, which comprises:

• coupling a surgical end effector to a handle having a shell, the end effector having at least one actuation assembly to effect a surgical procedure;
• mechanically coupling a drive train of an electric motor to the actuation assembly, the motor having a permanent magnetic field, the motor and drive train being disposed within the shell, and at least one of the motor, the drive train, and the actuation assembly having an inertia-induced over-stroke characteristic after powered operation;
• actuating the actuation assembly by selectively supplying the motor with power with a break-before-make power supply switch of a post-termination braking circuit, the break-before-make power supply switch having an off state that ceases supply of power to the motor;
• and
• upon ceasing supply of power to the motor, short-circuiting power terminals of the still-spinning motor with the off state of the power supply switch to create an electrically generated magnetic field in opposition to the permanent magnetic field.