Some car seats use only two teeth on the height adjustment control to get a suitable gear ratio. The two teeth are often just a loop of (springy) wire, arranged so that both teeth mesh in the intermediate positions to provide locking.

Interesting explanation of a drive type new to me. (Though I could have done with a bit less “philosophy”).

I wonder the true shape of the teeth, or lobes, in a fully-designed cycloidal gear-box.

His models, like Malcolm’s rack-and-pinion, seem to use the “knuckle” or “hollows-and-rounds” gear form – fine for demonstrating the principle but not real gearing.

Knuckle teeth were used in the long-past, for heavy, rough applications such as slow-moving winches, but they incur a lot of friction by rubbing rather than rolling action, and the velocity ratio varies within each tooth action.

So do the proper cycloidal gear-boxes use some sophisticated tooth form… if so, what?

Interesting Michael

H