A Hobson’s joint is a type of right-angle constant velocity joint; rods bent 90° are able to transmit torque around a corner because they are all free to turn in their mounting holes in both legs of the coupling.
This system demonstrates efficient gearless transmission of power at right angles. This saves gear manufacturing time and costs along with teeth matching and gear placement issues.
The elbow mechanism is an efficient design of gearless transmission technique and the kinematic system that allows for efficient power/motion transmission at right angles.
This mechanism allows for motion transmission at 90 degree angles between the driver and the driven shafts.Translating rotational motion around an axis usually involves gears, which can quickly become complicated, inflexible and clumsy-looking, often ugly.