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

1. A surgical instrument, comprising:

a surgical end effector;

at least one actuator mechanically coupled to the end effector for actuating the end effector;

a handle:

mechanically coupled to the end effector; and

having an electric motor disposed therein and operable to actuate the at least one actuator when the motor is supplied with power;

a post-termination braking circuit including a power supply switch at the handle, the power supply switch having:

a break-before-make switch 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,

the post-termination braking circuit operable to short-circuit the power supplied to the motor when the power supply switch is in the power-removed state.

2. The surgical instrument according to claim 1 , wherein the electric motor includes:

power terminals at which the motor is supplied with power; and

a drive train operatively coupled to the at least one actuator to actuate the at least one actuator when the motor is supplied with power,

wherein the post-termination braking circuit is operable to short-circuit the power terminals of the motor when the power supply switch is in the power-removed state.

3. The surgical instrument according to claim 2 , wherein the drive train has a rotational inertia when operating;

the motor has:

a rotational inertia when spinning; and

a permanent magnetic field; and

the post-termination braking circuit is operable to create an electrically-generated magnetic field in opposition to the permanent magnetic field with the rotational inertia of at least one of the drive train and the motor when short-circuiting the power terminals.

4. The surgical instrument according to claim 1 , wherein the handle further includes a power supply disposed therein and electrically connected to the motor through the post-termination braking circuit.

5. The surgical instrument according to claim 4 , wherein the power supply is a removable battery pack.

6. The surgical instrument according to claim 1 , wherein the power supply switch is a three-position switch including:

a forward position in which the three-position switch is in the power-supplying state and is configured to cause the motor to rotate in a forward direction;

a reverse position in which the three-position switch is in the power-supplying state and is configured to cause the motor to rotate in a reverse direction; and

an off position in which the three-position switch is in the power-removed state and the motor is caused to prevent rotation at the motor.

7. The surgical instrument according to claim 1 , wherein the power supply switch is a double-pole, double throw switch.

8. The surgical instrument according to claim 1 , wherein the end effector, the handle, the motor, the power supply switch, and the post-termination braking circuit are all operable with only a single hand.

9. 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,

the end effector having at least one actuator to effect a surgical procedure, and

the handle having an electric motor disposed therein;

mechanically coupling the motor to the at least one actuator;

actuating the at least one actuator by selectively supplying the motor with power with a break-before-make power supply switch of a post-termination braking circuit, the 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.

10. The method according to claim 9 , wherein:

the step of mechanically coupling the motor to the at least one actuator is carried out by mechanically coupling a drive train of the motor to the at least one actuator;

the motor has a permanent magnetic field;

at least one of the motor, the drive train, and the at least one actuator has an inertia-induced over-stroke characteristic after powered operation; and

the step of short-circuiting the power terminals of the motor creates an electrically generated magnetic field in opposition to the permanent magnetic field.

11. The method according to claim 10 , further comprising counteracting the inertia-induced over-stroke of at least one of the motor, the drive train, and the at least one actuator with the short-circuit.

12. The method according to claim 10 , further comprising carrying out the short-circuiting step to slow the still-spinning motor at a rate that substantially eliminates the inertia-induced over-stroke of at least one of the motor, the drive train, and the at least one actuator.

13. The method according to claim 10 , further comprising providing a power supply within the handle and electrically connecting the power supply to the motor.

14. The method according to claim 13 , wherein the power supply is a removable battery pack.

15. The method according to claim 13 , further comprising carrying out the short-circuiting step without short-circuiting the power supply.

16. The method according to claim 10 , further comprising:

providing a power supply within the handle and electrically connecting the power supply to the motor; and

carrying out the short-circuiting step without short-circuiting the power supply.

17. The method according to claim 10 , wherein the break-before-make power supply switch is a double-pole, double throw switch.