It is a constant velocity joint. There is a spherical joint between pink shaft and green one. For each shaft the opposite contact straight lines must be symmetric about the rotary axis and have a common intersection point with it. Angle between the two shafts reaches up to 30 deg. in this video. The mechanism can not be used for reversing rotation because of large backlash. Visit my blog here: http://bit.ly/2KvJRPc Follow me on