A spatial 4-bar linkage (pink rockers, violet cranks and green conrods) is used for converting oscillation into continuous rotation.
Washing tub is fixed to the base. Washing cage is fixed to the violet crank.
For easy start do not stop the machine at dead positions of the 4-bar linkage (where the violet crank and the green conrod are in line).
This mechanism may be used for the machine in video:
/watch?v=UMyhP0aeVLw