Geneva Escapment Wheel
Geneva Wheel
Geneva wheel in wood by Pierre Olivier.
The Geneva escapement wheel mechanism creates incremental rotation. Arm B is fixed to rotating wheel A. As A & B rotate, C rotates incrementally by 90 degrees for each full rotation of A & B. The Geneva escapement is particularly elegant in that the motion of C accelerates and decelerates smoothly.
The Geneva, also referred to as the Maltese cross, was originally used in mechanical watches. Normally the driven wheel has four slots to create 90 degree steps. However there can be more slots creating smaller angle steps.