Quick-change chucks

Claim 1

In a quick-change chuck comprising a cylindrical shank having a tubular wall, a tool socket axially slidable within said shank and adapted to receive a tool, an adjusting nut adapted to be screwed upon the font end of said socket for shifting said socket in its axial direction relative to said shank, said nut having a crylindrical neck portion and a peripheral groove within said nEck portion, a guide sleeve surrounding said shank and having on its front end an annular neck of a smaller diameter forming an inner shoulder adapted to abut against the front end of said shank, and having a plurality of transverse bores therein, a plurality of locking balls movable substantially radially within said transverse bores into and out of said peripheral groove, a spring-biased control sleeve surrounding and slidable axially along said guide sleeve for guiding the radial motion of said balls, said shank having a tapped bore and said guide sleeve having a hole substantially in alignment with said tapped bore when said shoulder on said guide sleeve abuts against the front end of said shank, and a setscrew inserted into said hole and screwed into said tapped bore for locking said guide sleeve to said shank, the improvement comprising means for ensuring the abutment of said shoulder on said guide sleeve against said shank so as to prevent movement therebetween consisting in providing said hole in the form of an elongated slot of a certain length extending in the peripheral direction of said guide sleeve and having a width substantially equal to the thickness of said setscrew and having a longitudinal axis slightly inclined relative to a plane extending vertically to the axis of said guide sleeve.