A drill chuck assembly. The drill chuck assembly includes a rapid change mechanism configured to retain a drill bit shank inserted therein. The drill chuck assembly includes a body having a bore with a trilobe cross-section that is configured to receive a triangular and hexagonally shaped drill bit shank, interchangeably. The bore includes a slot positioned in each lobe that slidably contains a detent ball therein. A collar is affixed annularly around the body and defines a channel extending around the body. A sleeve is slidably mounted around the body. The sleeve includes a tapered end that is slidably disposed within the channel and has circular apertures that are in communication with the slots of the bore for reception of the detent balls. The sleeve is spring biased towards the collar, which forces the detent balls against an angular wall within the channel. The angular wall in turn forces the detent balls laterally towards a center of the bore, thereby exerting a force on a drill bit shank inserted into the bore and preventing the withdrawal of the shank from the bore. When the bias force of the sleeve is counteracted by sliding the sleeve about its longitudinal axis, the detent balls move outwardly along the angular wall, thereby relieving the force exerted onto the shank by the wall and allowing the shank to be withdrawn.

A quick-change system for a tool holder comprises a machine-side receiving fixture having a hollow-cylindrical extension on which a switching sleeve is displaceably held. Automatic angular alignment of the tool holder upon introduction into the hollow-cylindrical extension of the receiving fixture is enabled by an alignment of the points of the star-shaped end face on the cylindrical holding portion of the tool holder, upon impact against a first set of three balls angularly spaced 120 apart. Once the tool holder has aligned itself in this way, then the first balls make their way into the longitudinal grooves of the cylindrical holding portion, whereby a rotationally fixed coupling is achieved. Upon the further insertion into the hollow-cylindrical extension, an axial securement finally occurs when a second set of three balls are displaced radially inward into associated depressions on the cylindrical holding portion.