High speed spindle and draw bar assembly

摘要

A machine tool high speed spindle assembly and draw bar assembly, wherein the spindle assembly includes a hollow, rotary spindle shaft, and the draw bar assembly is nonrotational relative to the spindle shaft. The draw bar assembly is axially movable within the hollow rotary spindle shaft, and it includes a tool holder gripping means. The draw bar assembly rotates with the hollow rotary spindle shaft during a machining operation. The draw bar assembly with its tool holder gripping means is moved by an actuator means between an operative position for retaining a tool holder or the like in the spindle shaft, and an inoperative position to permit a tool holder or the like to be removed from or inserted into the spindle shaft. A spindle shaft holding or gripping means retains the hollow rotary spindle shaft in a stationary position when the draw bar actuator means moves the draw bar assembly between said operative and inoperative positions. The draw bar assembly actuator means and spindle shaft holding means each comprise collet means having relatively movable collet members and collet clamp ring members. The draw bar assembly actuator means and spindle shaft holding means are free from the spindle shaft and have no physical contact with said shaft during a machine tool operation.