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| One-way shaft torque spanners? |
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| Bogstandard:
They are very good for making starter 'handles' for model ic engines. You can either mount one onto the flywheel of an engine and use a bit of the correct sized rod in an electric drill, or have a spigot on the flywheel, and the bearing mounted in the drill. They automatically freewheel when the engine starts and the speed exceeds the drill speed, and are then just pulled off. Bogs |
| Lew_Merrick_PE:
I use Sprag-type clutches with fair regularity. If you use dowel pins rather than balls, you can get a lot more torque transmitted. Properly designed, the roller elements act like a roller bearing when the shaft over-runs the applied torque. It's a bit harder to make them under-running, but it can be done -- I have only run into that requirement a few times. The main thing is to be sure that the angle on the locking reliefs has a tangent greater than the coefficient of friction between the roller element and the mating shaft. |
| John Hill:
One of the features of a roller ramp type clutch is that there may be very little, near as darnit no, backlash. I have an old electric clock with such a clutch which is vibrated at 50hz by a mains coil. The clutch causes the shaft to turn very slowly but with considerable torque to wind up a big spring. |
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