Abstract: A machining center of the type incorporating a spindle for driving tools wherein the spindle is movable rectilinearly along the axis of the spindle for engaging tool holders to move tool holders, and tools secured thereto, into an operative position wherein the tools contact a work piece. The rotational speed of the spindle, as well as its rectilinear motion, is controlled by a programmed numerical control center which also controls the bed upon which the work piece is mounted; the bed is movable, at predetermined rates, in the X, Y and Z directions. A positioning means, such as turret or carousel, is positioned beneath the spindle and is used to hold several tool holders, each of which supports tools for use in the machining operation. The tool holders are temporarily secured in the positioning means and are removed therefrom through the operation of the lowering spindle; the tool holders are formed in three sections, the first of which contacts and is driven by the rotating spindle.

Abstract: A tool holder for machine tools particularly adapted for use in turret structures having a plurality of retainers for holding a plurality of such tool holders each carrying a different tool such as a drill, tap, reamer or other metal working tool. The disclosure relates to a mechanically actuated tool holder having mechanical locking means adapted to snap into annular retainers in a turret structure of a mechanical tool and wherein locking means alternately is operable to hold the tool holder in the turret retainer ring and to lock the tool holder onto an annular ledge of a stub means carried by a rotatable and reciprocable machine tool driving spindle.