Patent ID: 7367245

Claim:
A joint structure comprising: a first structure; a second structure; a revolute joint for connecting the first structure and the second structure; a rotating guide pulley which is coaxial with a rotating shaft of the revolute joint and arranged so as to be rotatable about the rotating shaft; a fixed guide which is arranged in the first structure, the fixed guide having an arc portion; a movable rotating guide pulley which is arranged in the second structure so as to be relatively movable; a wire which is put round the rotating guide pulley, the movable rotating guide pulley, and the fixed guide in an order of the rotating guide pulley, the movable rotating guide pulley, and the fixed guide; a first drive apparatus, which is included in the first structure, for rotating the second structure about the revolute joint without changing a distance from the movable rotating guide pulley to the rotating guide pulley; and a second drive apparatus, which is included in the first structure, for driving the wire, and moving the movable rotating guide pulley to change the distance to the rotating guide pulley by driving the wire, wherein the second structure is rotated about the revolute joint by driving the first drive apparatus without changing the distance from the movable rotating guide pulley to the rotating guide pulley.