Patent ID: 8511197

Claim:
A robot arm assembly comprising: a support arm; a lower arm rotatably connected to the support arm, the lower arm comprising a rotating base and two support rings mounted on two ends of the rotating base and received in the rotating base, respectively; an upper arm rotatably connected to the rotating base of the lower arm; a first driver for driving the lower arm; a first transmission partly received in one of the two support rings, and transferring power from the first driver to the rotating base of the lower arm; a second driver driving the upper arm, the second driver positioned on the first driver, and parallel to the first driver; and a second transmission transferring power from the second driver to the upper arm, wherein the first and second drivers are mounted on the support arm, and the second transmission comprises a belt assembly, a beveled gear assembly driven by the belt assembly, and a speed reducer coupled to the upper arm, the beveled gear assembly partly received in the other one of the two support rings.