I have a setup where a stepper motor turns a timing pulley, which in turn turns another pulley clockwise on a shaft. When the stepper motor is not turning, I want the shaft to be able to rotate freely clockwise (counter-clockwise would be OK too, but there won’t be any forces in that direction).
I’ve been looking at one way bearings, but another possibility is to just loosen the timing belt somehow, and then re-tension it when the stepper needs to drive the shaft again. Can anyone advise me how I would do something like this?
Is simply removing power from the stepper an option (there will be some inherent torque to overcome, but a magnitude smaller than if the motor was powered)?
You could add a third (free spinning) pulley system on a servo which keeps tension on the timing belt but moves it away from the motor’s pulley.
If you can provide more insight into the project, we may be able to propose additional options.
Removing power from the stepper wouldn’t help (already tried it). There’s still too much torque.
I have an old digital flip-clock. I want to use the stepper to automatically set the time (received by GPS). I had everything working great and then I discovered that the shaft for setting the time rotates as the clock advances. So the stepper motor set the time OK, but then the clock stopped advancing because the clock’s motor couldn’t turn the shaft.
I thought of getting rid of the clock’s motor and having the stepper advance the time every minute, but that’s a lot noisier.
Alan said it - a clutch of some sort seems best.
If the torque during rotation is not too strong, even two disks with magnets would work.
Experiment with the magnets to get the right force to be able to manually rotate it when it’s not powered.
