one-way clutch questions

I have an application that I need to rotate a shaft at about 3 rpm. The shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104 teeth on the ratchet. I want to use a gearmotor and chain drive to move the last 6 steps stopped by a limit switch. I don't think I'll need a brake and the ratchet wheel has 2 pressure brakes on it to take the jar out of the ratchet. I also want the gearmotor to "walk" the shaft around for troubleshooting. All my other machines use an 2.5" air cylinder mechanism to advance the ratchet the extra teeth. One of these cylinders is $600 plus the rest of the mechanism for $1000. I think the gearmotor will be cheaper and better.
My question: I want a one-way clutch so the chain drive will just coast while the machine ratchets. Is there a one-way clutch that I can mount on the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the clutch?
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Mcmaster has lots of variations on those. The ones I've used are called "One-Way Locking Steel Needle-Roller Bearings" available up to 1" shaft. Standard looking needle roller bearing assembly, acts as a bearing one way, locks tight the other. Torque capacity might not be high enough for your use.
Tom Gardner wrote:

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Tom Gardner wrote:

Perhaps check the one way bearings on http://www.mcmaster.com
The overrunning clutch couplings they have don't seem to quite be it, but at your low speeds might work.
Pete C.
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Tom Gardner wrote:

Google "sprag" such as these:

http://www.renold.com/Renold/web/site/Products/SpragClutchFreewheels/Sprag_Clutch_Index.asp
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On Wed, 22 Feb 2006 22:36:09 GMT, "Tom Gardner"

Google sprag or roller ramp clutch. A quick check shows the following company has something that might work.
http://www.renold.com/Renold/web/site/Products/SpragClutchFreewheels/Sprag_Clutch_Index.asp
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EXACTLY!!! Thanks!
wrote:

http://www.renold.com/Renold/web/site/Products/SpragClutchFreewheels/Sprag_Clutch_Index.asp
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the
and
plus
cheaper
If you do or can use cycle chain then cycle freewheels would be a cheap solution.
You can, however, only obtain versions that clutch in one direction...
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On Wed, 22 Feb 2006 22:36:09 GMT, "Tom Gardner"

Horton Air Clutch with a solenoid to disengage power train when you want it to coast. Ive got about 30 of them.
Tom...perhaps its time to make a road trip to Taft..I think Ive got Stuff you need. Free to you.
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3
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