Surgical drill having a brake that, upon the drill bit penetrating through bone, prevents further insertion of the drill

1. A surgical drill assembly comprising:

a handpiece with a motor, a chuck attached to the motor for releasably holding a drill bit to the motor so the drill bit can be rotated by the motor;

a telescoping member having opposed proximal and distal ends, a proximal section of the telescoping member moveably mounted to the handpiece to allow the telescoping member to move proximally and distally along the handpiece and a stop attached to the distal end of the telescoping member so as to be located at a distal end of the drill assembly;

a brake assembly is attached to said handpiece, said brake assembly including a member having:

a brake that is moveably attached to said handpiece to move between engaged and disengaged positions with the telescoping member, wherein when the brake is in the engaged position with the telescoping member, said brake stops movement of the telescoping member; and

an actuator, that in response to a command signal, selectively moves said brake from the disengaged position to the engaged position;

wherein the telescoping member comprises a plurality of teeth, and the brake comprises a plunger moveable between the engaged and disengaged positions, such that the plunger is configured to engage the teeth of the telescoping member when the plunger is in the engaged position and the plunger is configured to disengage the teeth of the telescoping member when the plunger is in the disengaged position.

2. The surgical drill of claim 1 , wherein:

the handpiece has an end: and

said brake and said actuator are mounted to the handpiece so as to be located adjacent to the end of said handpiece.

3. The surgical drill assembly of claim 1 , wherein:

said plurality of teeth of said telescoping member extends proximally to distally along the telescoping member; and

said brake is formed with a tooth dimensioned to, when the brake is in the engaged position seat between said plurality of teeth of said telescoping member.

4. The surgical drill assembly of claim 1 further including the actuator that normally holds the brake in the disengaged position.

5. The surgical drill assembly of claim 1 , wherein said actuator is a solenoid.

6. The surgical drill assembly of claim 1 , wherein:

a sensor is mounted to said handpiece to monitor when said drill bit penetrates through bone and asserts a sensor signal indicative of when the drill penetrates through bone;

a control circuit is mounted to said handpiece to receive from said sensor the sensor signal indicative of when said drill bit penetrates through bone and, in response to receipt of the sensor signal, asserts the command signal to said actuator that causes said actuator to move said brake from the disengaged position to the engaged position.

7. The surgical drill assembly of claim 6 , wherein said motor is an electrically powered motor; and said sensor is configured to monitor when the drill bit penetrates bone by monitoring current draw of said motor.

8. The surgical drill assembly of claim 1 , further including a depth gauge mounted to the handpiece to monitor the movement of the telescoping member.

9. A surgical drill assembly comprising:

a handpiece with a motor, a chuck attached to said motor for releasably holding a drill bit to said motor so the drill bit can be rotated by the motor;

a telescoping member having opposed proximal and distal ends, a proximal section of the telescoping member moveably mounted to the handpiece to allow the telescoping member to move proximally and distally along the handpiece and a stop attached to the distal end of the telescoping member so as to be located at a distal end of the drill assembly, where at least a portion of said telescoping member is located proximal to the drill bit and is at least partially contained in the handpiece; and

a brake that is moveably attached to said handpiece to move between engaged and disengaged positions with the telescoping member, wherein when the brake is in the engaged position with the telescoping member, said brake stops movement of the telescoping member; and

an actuator, that in response to a command signal, selectively moves said brake from the disengaged position to the engaged position;

said motor has a rotor with an axially extending throughbore;

a portion of said telescoping member is slidably disposed in the throughbore of the motor rotor and extends out of a proximal end of the motor rotor; and

said brake is mounted to the handpiece so as to be located proximal to the motor so as to engage a portion of the telescoping member that extends proximally from the motor.

10. A surgical drill comprising:

a handpiece with a motor, a chuck attached to the motor for releasably holding a drill bit to the motor so the drill bit can be rotated by the motor;

a telescoping member having opposed proximal and distal ends, a proximal section of the telescoping member moveably mounted to the handpiece to allow the telescoping member to move proximally and distally along the handpiece, the distal end shaped to abut tissue adjacent tissue into which the drill bit bores; and

a retraction assembly attached to the telescoping member and capable of, simultaneously with actuation of the motor to rotate the drill bit retracting the telescoping member proximally so the distal end of the telescoping member is retracted proximally away from a distal end tip of the drill bit, wherein said retraction assembly is connected to said motor so that said motor, simultaneously with the rotation of the drill bit, causes the retraction assembly to retract the telescoping member proximally;

wherein the telescoping member is a sleeve that is disposed over the drill bit.

11. The surgical drill assembly of claim 1 , wherein the actuator comprises a solenoid configured to be energized and move the plunger to the engaged position where the plunger engages with the plurality of teeth of the telescoping member.