Patent ID: 8286528

Claim:
A robot arm, comprising: a drive gear having a shaft; a gear frame configured to turn about the shaft of the drive gear; a first follower gear configured to turn, in synchronization with the drive gear, about a shaft fixed to the gear frame, in a direction opposite to the turning direction of the drive gear; a transmission control mechanism configured to lock the first follower gear to the drive gear; an arm configured to move in synchronization with the first follower gear; and a collision detection unit configured to detect a collision between the arm and an obstacle, wherein the transmission control mechanism is configured to unlock the first follower gear from the drive gear in response to the detection, by the collision detection unit, of a collision between the arm and the obstacle, and wherein when the first follower gear is locked to the drive gear by the transmission control mechanism, the gear frame turns about the shaft of the drive gear, and when the unlocking is effected, the gear frame is locked so as not to turn about the shaft of the drive gear.