Abstract: The actuating unit mounts a workpiece gripping and transporting jaw assembly and has an elongated hanger rod supporting a first mount boss. A pneumatic cylinder is arranged below the rod and secured to the boss and has a conventional piston and piston rod projecting from the cylinder. The improvement which comprises an elongated guide rod between the cylinder and hanger rod slidably positioned through the mount boss projecting forwardly thereof and at one end supporting a jaw mount assembly having a longitudinal bore. A stroke adjuster collar is secured upon the other end of the guide rod and adapted to limit forward movement of the jaw mount assembly. A rod adapter is movably positioned through the bore of the jaw mount assembly which includes a first mount flange on the forward end thereof. A jaw assembly includes a body having an annular mounting flange at one end mounted upon the first mount flange and adjustably secured thereto.