Replaceable gang head machine tool

A replaceable gang head machine tool unit comprising a base, a slide table mounted on said base for movement between retracted and advanced positions, an annular rail on said machine base including a rear stationary portion and a front movable portion, a plurality of gang heads mounted on said rail for travel thereon, said gang heads being disposed in angular spaced relation on said rail, a rotatable index table mounted on said base above said rail in coaxial relation therewith, means detachably connecting said index table to said gang heads to advance the gang heads on said rail in accordance with the rotation of said index table, said gang heads successively passing through an operating position, a working unit carried on said slide table and movable therewith between a rearward inoperative position and a forward operative position, said gang heads in said operating position being proximate said working unit in said rearward operative position thereof, means on said working unit and on said gang heads for (a) detachably coupling said working unit with the particular gang head at said operating position as said working unit advances from said rearward inoperative position to said forward operative position and (b) for releasing the coupled gang head from said working unit as said working unit travels from said forward operative position to said rearward inoperative position, said means which detachably connects the index table with the gang heads comprising a pin and slot connection in which a pin is slidably movable in a slot and separable therefrom, said index table having grooves therein forming a Geneva gear, and means for driving said index table in rotation including a drive motor and a Geneva pin driven by said motor and engaged in the grooves in the index table to effect stepwise rotation of said index table.