Robotic tool changer coupling mechanism with increased torsional rigidity and reduced freeplay

Abstract

To substantially eliminate torsional freeplay in a robotic tool changer having a ball-lock coupling mechanism, scallop-like features in the form of cross-contact recesses are formed in at least one of, and preferably both of, a bearing race in a tool assembly at the points of contact of rolling members, and in the opposing inner surfaces of bores containing the rolling members in a master assembly. The cross-contact recesses are sized and shaped to receive a rolling member, but have a central void, or channel, perpendicular to the rolling member's motion in torsional freeplay, which does not contact the rolling member. The cross-contact recess contacts the rolling member at contact areas on either side of the central void. These contact areas impart two separate contact forces on the rolling member, both angled toward the center of the rolling member and hence operative to prevent side-to-side movement, or rocking, of the rolling member within the cross-contact recess, and hence substantially eliminating torsional freeplay of the robotic tool changer.