Redundant safety lock mechanism

A surgical instrument having an axis, the surgical instrument comprising:

• a housing having forward and rearward ends;
• a motor mounted on the housing adjacent the rearward end;
• a tool implement having a recess spaced from one end;
• a tubular shaft having a bore and an aperture and being located within the housing for receiving the tool implement in the bore adjacent the forward end, the shaft aligning with the axis and being rotated by the motor;
• a locking element which moves radially inward into the aperture to engage the recess on the tool implement in a locking position, and which moves radially outward out of the aperture and the recess to a released position wherein the tool implement may be disengaged from the tubular shaft;
• an actuation sleeve surrounding the shaft and operably associated with the locking element, the actuation sleeve being axially movable between locked and released positions to permit movement of the locking element between its locked and released positions;
• a coaxial safety sleeve which is rotatable between locked and unlocked positions relative to the actuation sleeve;
• and
• a pin secured to the actuation sleeve or the safety sleeve and a mating slot in the other of the actuation sleeve and safety sleeve, whereby, when the actuation sleeve is in its unlocked position, the pin registers with the slot to allow the actuation sleeve to move axially between its locked and released positions, and when the safety sleeve is in its locked position, the pin is misaligned with the slot for preventing the actuation sleeve from moving from its locked position.

A surgical instrument having an axis and a motor, comprising:

• a housing having forward and rearward ends;
• a motor mounted on the housing adjacent the rearward end;
• a tool implement having a recess spaced from one end;
• a tubular shaft having a bore and an aperture and being located within the housing for receiving the tool implement at the forward end, the shaft aligning with the axis and being rotated by the motor;
• a locking element which moves radially inward into the aperture to engage the recess on the tool implement in a locking position, and which moves radially outward out of the aperture to a released position wherein the tool implement may be disengaged from the tubular shaft;
• an actuation sleeve surrounding the shaft and operatively associated with the locking element, the actuation sleeve being axially movable between locked and released positions to permit movement of the locking element between its locked and released positions;
• a coaxial safety sleeve which is rotatable between locked and unlocked positions relative to the actuation sleeve, the safety sleeve being located axially rearward and radially outward of the actuation sleeve;
• a pin secured to the safety sleeve and a mating slot in the actuation sleeve, whereby, when the safety sleeve is in its unlocked position, the pin registers with the slot to allow the actuation sleeve to move axially between its locked and released positions, and when the safety sleeve is in its locked position, the pin is misaligned with the slot for preventing the actuation sleeve from moving from its locked position;
• a ball and detent operatively associated with the safety sleeve to releasably retain the safety sleeve in its locked position.