US Patent 10414044 Robot arm and robot system

A robot arm includes a first holder and a second holder. The first holder includes a first base portion and a first distal portion. The first distal portion has a first distal thickness smaller than a thickness of the first base portion. The second holder includes a second base and a second distal portion. The second distal portion has a second distal thickness smaller than a thickness of the second base portion. A first rotator is supported by the first distal portion and the second distal portion. A second rotator is supported by the first rotator. A first bevel gear is provided in the first distal portion. Another first bevel gear is provided in the second distal portion. A second bevel gear engages with the first bevel gear and the another first bevel gear.