US Patent 7765891 Robotic compliance mechanism

A mechanism provides compliance between a tool and a robotic arm and includes a base with a first face. The mechanism includes a post assembly with a thrust washer and a mounting post attached to the thrust washer. The thrust washer engages the first face to form a compliance joint that permits a compliance range of sliding translational motion along the first face. The mechanism comprises springs that slideably engage an outer rim surface of the post assembly and providing a compliance force resisting the sliding translational motion. A retainer is mounted to the base and compresses the thrust washer against the first face and limits rotational motion of the assembly out of a plane of the first face.