Patent ID: 7156005

Claim:
A hand tool having a chuck with a central axial opening where a tool element is movable from a retracted position in said hand tool where it is not in said chuck, through the opening to an extended operative position where at least a portion of said tool element extends from said chuck, said chuck comprising a locking means, configured such that said hand tool element is advanceable from its retracted position to its operative position without user manipulation of said chuck and such that as said tool element reaches its operative position, said locking means automatically engages said tool element and locks it in place in said chuck, such that said tool element then cannot be retracted without user intervention; said locking means comprising a mechanical element biased towards engagement means on said tool element, so that once the mechanical element is engaged with said tool element, said tool element cannot be retracted from its operative position, and further comprising means for retracting said mechanical element, operable by a user to permit said tool element to be retracted.