A rotary indexing table comprises a stationary gear mounted on a base, a rotary drive mounted within the base and carrying a first crank arm, and a planetary gear on the first crank arm engaging the stationary gear. A second crank arm is mounted on the planetary gear, and has a freely rotatable drive stub which engages and drives a radially directed force receiving member mounted on a rotatable table. The rotation axis of the freely rotatable drive stub overlies the circumference of the planetary gear; and as the planetary gear rotates, the drive stub is coupled to the force receiving member so as to freely move along it in a reciprocating manner. When the longitudinal axis of the first and second crank arms are aligned, the indexing table is locked in place and cannot be moved by an external force. One of the stationary gear and the planetary gear comprises a gear assembly having two identical gears, one of which is slightly rotationally offset with respect to the other, so that there is no backlash between the gears no matter which direction the planetary gear is rotating as it moves around the periphery of the stationary gear.

The invention relates to a workpiece support assembly including an indexing unit adapted for the automated adjustment of a workpiece being machined. The assembly includes a central support column having at least one indexing unit secured thereto. The indexing unit includes a base member integrated with the central support column, a main body to which a workpiece may be selectively secured and a locking assembly permitting the selective locking and rotation of the main body relative to the base member. The main body is mounted on the base member for selective rotation required to rotate a workpiece as mounted.

An indexing device and method is provided to selectively orient work pieces at predetermined angular positions and hold the work pieces at those positions. The indexing device has a rotary member rotatably coupled to a support and a trigger pivotally coupled to the support. The rotary member holds a fixture and has a plurality of index pins extending from the rotary member at equally spaced about the axis of rotation. The trigger operates a stop assembly to engage holes in the rotary member to position the working holding fixture at the desired position. The indexing device is constructed such that the trigger and one of the index pins can be simultaneously contacted by a control member. The trigger includes an elongated contact surface along which the control member translates to contact the index pins and rotate the rotary member.