Abstract: A method and apparatus for automatically changing interchangeable machining tool heads carried by a tool carrier. The tool heads are suspended from an overhead trolleyway by leading and trailing trolleys, with the leading trolley carrying a probe and a vertical finger and the trailing trolley carrying an inclined guide. The vertical finger selectively engages a block carried on an overhead moving chain for moving the tool head toward the tool carrier. The probe extends in the direction of tool head travel and is responsive to proximity of the probe to the inclined guide of another tool head or to a pneumatically-actuated stop for disengaging the vertical finger from the chain. A shuttle bar assembly simultaneously loads and unloads tool heads from the tool carrier by engaging a block on each of the tool heads and moving the tool heads horizontally to loaded and unloaded positions.

Abstract: A mechanical quill and spindle drive mechanism is disclosed wherein the quill is advanced by means of a screw formed about its periphery and cooperating with a driven ball nut. The quill is received within a housing bore and accurately guided for longitudinal movement thereby by means of a sliding engagement with bore surfaces on either side of the nut. The spindle is carried by the quill throughout its longitudinal movement and is rotated by means of a splined drive shaft which maintains a rotative connection therewith by means of a splined connection therebetween.