wheel a simple machine consisting of a circular frame with spokes (or a solid disc) that can rotate on a shaft or axle (as in vehicles or other machines)
tooth a means of enforcement; "the treaty had no teeth in it"
worm gear gear consisting of a shaft with screw thread (the worm) that meshes with a toothed wheel (the worm wheel); changes the direction of the axis of rotary motion
cogwheel -
When used attributively Something behaving in similar, jerky, manner as a cogwheel, e. g. cogwheel respiration as a side effect of hyperbaric medicine.