Diaphragm chuck

A diaphragm chuck comprising a support having a central axis, a generally circular, resiliently flexible diaphragm concentric with said central axis and having its outer periphery fixedly connected to said support, actuator means on said support engageable with the diaphragm for flexing it axially about its periphery as a fulcrum, a plurality of circumferentially spaced individual jaws fixedly mounted on the diaphragm around a circle concentric with said central axis, said jaws being disposed radially inwardly from the outer periphery thereof and projecting axially outwardly from said diaphragm, the axially outer end portions of said jaws being displaced radially in an arcuate path in response to flexing of the diaphragm, a circumferentially continuous ring, means releasably mounting said ring on said jaws in a circumferentially fixed position, said ring having a plurality of radially movable pins thereon registering with said jaws, said jaws having axially extending shoulders thereon engaging one end of said pins, the opposite ends of said pins having means thereon for gripping a peripheral surface of a workpiece whereby, when the diaphragm is flexed axially in one direction, said pins are retracted sufficiently to receive a workpiece and, thereafter, when the diaphragm is flexed axially in the opposite direction, the axially extending shoulders on said jaws displace said pins radially to firmly clamp the workpiece, said ring having a plurality of flanges thereon extending radially in one direction, said jaws having flanges thereon extending radially in the opposite direction and overlying the flanges on the ring, the arcuate space between the flanges on successive jaws being greater than the arcuate extent of the flanges on the ring so that the ring can be positioned with the flanges thereon located between the flanges on the jaws and then rotated to position the flanges on the ring behind the flanges on the jaws.