Patent ID: 8475093

Claim:
A clamping unit for releasably holding a tubular shank of a toolholder, comprising: a) a base member with 1) a longitudinal axis extending therethrough; 2) a forwardly facing exterior surface; and 3) a bore extending inwardly from the forwardly facing surface for receiving the toolholder shank; b) a lock rod movable within the base member along the longitudinal axis in a forward and rearward reciprocating motion, wherein the lock rod has at least one longitudinally extending depression and an adjacent ramp, such that in the rearward position locking balls are radially displaced by the ramp to engage the toolholder shank within the base member and in the forward position the locking balls retract into the depression and release the shank from the base member; c) a canister sleeve mounted within the base member bore with the sleeve outer surface adjacent to the bore wall and the sleeve inner surface surrounding at least a portion of the lock rod, wherein the canister sleeve has radial apertures for guiding the locking balls between the lock rod and the tubular toolholder shank; d) a shoulder extending inwardly within the base member bore, wherein the canister sleeve abuts with an intermediate stop ring or directly with the shoulder to limit rearward motion of the canister sleeve; e) a retention bore extending through the base member along a retention bore axis having an axial component extending into the base member bore; f) a slot within the canister sleeve, wherein the slot has a locating surface generally perpendicular to the retention bore axis and has a deflecting surface, wherein the deflecting surface forms a positive angle X with respect to the retention bore axis; and g) a retention bolt threadably mated within the retention bore to contact the canister slot surfaces and clamp the canister sleeve within the base member bore, whereby the retention bolt contacts the locating surface and contacts and is deflected by the deflecting surface in a radial outwardly direction, thereby applying a radially inward and axially rearward force to the canister sleeve.