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. This system is used to demonstrate the transmission of power at right angle without the use of any gear or gear drives.
image/source: Live Tech Point
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.
Here is a wonderful mechanism that carries force through a 90 degree bend. Translating rotational motion around an axis usually involves gears, which can quickly become complicated, inflexible and clumsy-looking, often ugly.
This mechanism allows for motion transmission at 90 degree angles between the driver and the driven shafts. This method only work when you want the same velocity that you have in the input in your output.