Ratchet/slip bearing?

[Ianworld]

I've found over the years that before i should try to make anything i should always see if i can just buy it. Right now what I'm looking for is a bearing that slips in one direction. Think like a ratchet, it will catch in one direction but spin freely in the other. Its what you find in bicycle rear wheels that allows you to pedal but also slip. If anybody knows what the name of such a bearing is I would be quite thankful if you could divulge your knowledge to me. Even better is if you know where i can find one.

~Ian

[sanddrag]

Typically it is called a one-way-bearing. I'm not sure where to get it. What are you trying to do? Can you use a ratchet, or do you need a bearing.

[Al Skierkiewicz]

I've found over the years that before i should try to make anything i should always see if i can just buy it. Right now what I'm looking for is a bearing that slips in one direction. Think like a ratchet, it will catch in one direction but spin freely in the other. Its what you find in bicycle rear wheels that allows you to pedal but also slip. If anybody knows what the name of such a bearing is I would be quite thankful if you could divulge your knowledge to me. Even better is if you know where i can find one.

~Ian
The term is "clutch bearings" and they are available from McMaster-Carr, p1014 of catalog 109 or just search on their website.

[greencactus3]

how large a one do you need? you can buy small one way bearings for rc cars (oneway pulleys/oneway diffs) in many hobby stores

[coreyjon]

-Or if you have any of the old bikes around, you could always find away to salvage just the clutch bearing-Or, you can order a nice shiny new one from McMC. I've used them in the past in projects not relating to robotics, and last year when I wanted a unidirectional drive system for the robot ascender, so that it would not backdrive both globe motors, I used a system found on many boat trailers, It was possible to back drive, by pulling the spring loaded latch back - and forcing it all the way up to hit a saftey limit switch (so that the drivers couldnt try to fight the one way mechanism in game) then you could run the system backwards to rewind the spool. What do you have in mind for the clutch bearing? that is if it isnt top secret.

[team222badbrad]

http://www.zxz-bearings.com/onewaybrg.htm

[team222badbrad]

http://www.smallparts.com/

Search for roller clutches

They have up to 3/4 inside diameter