geneva
A 6-slot Geneva wheel
The driving pin enters a radial slot, carries the wheel through 60°, and leaves. The centre distance is not free: it must be crank ÷ sin(180°/6) = 60.00 so that the pin enters *along* the slot, with the crank and slot perpendicular. That is the mechanism's one design requirement and it is what makes the driven wheel start and stop from rest — measured here at 1.5e-3 against a peak of 1.000. What it does not fix is the acceleration, which peaks at 1.35 and is why film sprocket holes tear.
Prescribed motiondraggable: driver anglewide
Where it is used
- Stopping thirty times a second Prescribed motion
- The escapement that could not alternate Drawn wrongly
- The gear with its teeth cut away Motion that stops
- Detached, and safe while detached Motion that stops
- Two pins and no dwell at all Motion that stops
- The disc decides the pin count Motion that stops
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