US Patent 8079578 Universal holding fixture

A universal holding fixture assembly includes a plurality of linear actuators supported by the fixture and adapted to engage and support a workpiece relative to the fixture. A linear displacement member is supported by a housing and adapted to move between retracted and extended positions. An end effector assembly is operatively supported by the linear actuator and adapted to engage the workpiece when the linear displacement member is in its extended position. A sensor is operatively supported by the end effector assembly and is responsive to contact with the workpiece to establish a datum of the position of the linear actuator relative to the workpiece.