Spindle lock with impacting capability

Claim 1

A power tool comprisng, a housing, a spindle journaled in the housing, a spindle lock member rotating with the spindle inside the housing, a recess in the perimeter of the lock member having substantial angular embrace, a lock pin reciprocably mounted in the housing for movement between an inactive position and an operative position in which it projects into said recess, means biasing the lock pin to its inactive position, blocking means coaxial with the spindle and extending radially beyond the lock member into the path of movement of the lock pin to prevent movement of the lock pin to its operative position, means biasing the blocking means into frictional engagement with the lock member so it normally rotates with the lock member but may be restrained from such rotation, said blocking means having an opening therein permitting passage of the lock pin therethrough when the lock pin is aligned with the opening but precluding entry of the lock pin when the blocking means is rotating at high speed, a major dimension of the cross-section of said lock pin being substantially less than the angular embrace of said recess whereby said spindle is capable of substantial angular movement relative to the lock pin when the lock pin is in its operative position to permit impacting the ends of the recess against the lock pin.