US Patent 7762156 Cable-driven wrist mechanism for robot arms

A cable driven wrist mechanism for a robot arm which executes a rolling motion and a pitching motion. The wrist mechanism includes a first drive body and a second drive body which are independently driven. The wrist mechanism includes first and second rotary bodies which are connected to the first and second rotary bodies. The wrist mechanism further includes a third drive body perpendicular to the first and second drive bodies. At least two cables are connected between the drive bodies and the rotary bodies in a criss-cross manner to transmit forces of the first and second rotary bodies to the third rotary body.