Abstract: A transmission device is provided, including a first housing, a second housing connected to the first housing, a third housing axially connected to the second housing, an adapter disposed on the third housing, a first power shaft actuating the first housing and the second housing to rotate, a second power shaft actuating the third housing to rotate, and a third power shaft actuating the adapter to rotate. The second and third power shafts are a coaxial structure. The first power shaft is an independent rod. Therefore, a motor loaded with a smaller rotation inertia and being thus cheaper can be used to drive the first power shaft, and the transmission device can have a reduced cost.

Abstract: A load balancing device for a robot arm including a pneumatic cylinder and a piston rod is provided. The pneumatic cylinder, used to store a gas, includes a first chamber, a second chamber and a communicating passage, wherein the communicating passage connects the first chamber and the second chamber. The piston rod has one end connected to the robot arm and the other end slidably disposed in the pneumatic cylinder. The piston rod adjusts the volume and the pressure of the gas in the first chamber and the second chamber according to a load, wherein the first chamber and the second chamber are coaxially disposed in the axial direction of the pneumatic cylinder.