Abstract: An end effector for use with a robotic mechanism is disclosed which is capable of grasping cylindrical workpieces having a varying diameter off center and holding it with six degrees of freedom. The end effector has a plurality of sets of fingers, each set having three fingers which radially approach and retract from the workpiece with a spacing of 120 degrees between the movement direction of the fingers. The movement of each of the fingers in a set are coplanar, and the planar movement of each set of fingers are parallel with each other. Each finger is actuated by its own hydraulic cylinder which causes it to independently engage the workpiece. The cylinders are hydraulically operated by a hydraulic system having a pressurizing pump for flowing fluid from a tank through a bidirectional valve to a series of pilot operated check valves and then to the cylinders. The setting of the bidirectional valve determines whether the fingers grasp the workpiece or release it.

Abstract: An apparatus which acquires individual articles having a substantially cylindrical aperture therein from a supply of roughly aligned articles in a storage bin. The apparatus grips the article on the interior wall of the cylindrical aperture therein. The gripper is moved to retract the article from the storage bin. The article is then moved to a receiving member which aligns the longitudinal axis of the cylindrical aperture of the article substantially parallel or coincidental with the longitudinal axis of the receiving member.

Abstract: A wrench has a pair of jaws which oppose each other to define the wrench opening. One of these jaws is pivotally mounted on the wrench body while the other may be fixed and integral with the wrench body. The pivotal jaw pivots in opposite directions so as to close the wrench opening and engage and drive a nut or bolt head when turned one way and to open the wrench opening and turn freely about the nut or bolt when turned the opposite way. The pivot about which the pivotal jaw rotates is on the same side of the wrench opening as the pivotal jaw itself such that the sum of the moments of the forces on the pivotal jaw close the jaw and align it with the nut or bolt head automatically at the start of the forward or driving stroke without any lost rotational motion or the need for springs or special cam surfaces.