One way bearing for filament retraction

[ScrewYouGravity]

Hi everyone,

I am currently working on an upgrade to a 3D printer filament spool holder. I have been looking for a passive system which allows the free turning of a spool in one direction and engages is with a motor in the other direction.

I have experimented with one way bearings however I have only been able to come up with a system where the motor does not engage when activated as it is in the same "free wheel" direction as the spool. Does anyone have an example of a design which does this and allows you to engage the motor in the direction opposite to the required freewheeling direction?

Thank you for your help!

 

[Compositepro]

What is an acceptable torque for "free-wheeling"? Will a slip clutch which has equal torque in either direction work for your application? The clutch can also be turned-off to free-wheel.

 

[3DDave]

Such as a bicycle free-wheel?

 

[TugboatEng]

You need a magnetic clutch.

 

[ScrewYouGravity]

Thanks all for your replies.

The free-wheeling resistance has to be very low to avoid causing issues in the print. An active slip clutch or magnetic clutch would work to engage/disengage the motor, I was just wondering whether there was a passive solution I hadn't yet discovered.

Unfortunately the powered direction is opposed to that of a bicycle free-wheel. I will keep investigating miniature clutches to find the best option. Thank you!

 

[3DDave]

Reversing the direction the filament spool is loaded will reverse the action needed from a freewheel; similarly, changing which side of the freewheel is fixed reverses the freewheel action. Finally, adding an idler will reverse the action.