OT: Ratcheting bearing?

I have something that matches this description. Looks like a needle bearing around a shaft, two of 'em, one on each end. one way rotation each.

This one is marked "Torrington By the way. I recall a clicking sound made by some geared bicycles

You know, I need to start reading ahead before I start writing. Saab used just this sort of thing from 1949 to around 1970 on the driveshaft between engines and transmission, here's a link with a great graphic and explaination of how it works:

Scroll down the page to the sprag style torrington bearings.

Yeah, OK, it's a roller type sprag bearing, the inside of the cups look like the inside of a needle bearing and the shaft is described previously.

Thanks for the link, I have several old Saabs, and the freewheel is no longer available. I have a tranny to rebuild and might be able to use these to improve the design (or at least match it with something I can actually get).

On Fri, 17 Aug 2007 22:41:13 GMT, with neither quill nor qualm, John Doe quickly quoth:

No, not really, unless the diameter of the needle sprag is smaller than the deformities and gouges on the shaft.

Got lathe? Turn one yourself!

-- Seen on a bumper sticker: ARM THE HOMELESS

Torrington specifies a shaft hardness of Rc58, finish about 16 uinch, and a diameter of .2500/.2495

Go back to McMaster and order p/n 6061K411, which is a 3" length of linear (Thomson) shaft, and it'll be about as close as you're going to get to the specs in an off-the-shelf part. If you really need 1" long, you'll have to use carbide tools in a lathe or an abrasive disc to cut it.

A 1/4" dowel pin would also work, but will be a few tenths over .250 nominal diameter - probably won't matter and should be available locally 1" long.

you are right. it just didnt look correct until I stopped.

Yep,yep ,yep ... I think MSC has them

Go look at the rope rewind mechanism on your lawnmower. I'm sure you'll see the simplicity of its ratchet.

Maybe not what you want, but a starting point for thought.

technomaNge

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How do you match the shaft with the spring?

Are there matched pairs made of common springs and shafts?

Could you just go with the same inner and outer diameter for the spring and the shaft?

Those are my questions.

If an extension spring can be put on the motor shaft sticking outwards toward the drive shaft, and be longer than the drive shaft it's going to slide onto, there could be a momentary and even flexible application of the one-way drive shaft? It would just have to easily slide onto and off of the drive shaft, and still grip in the forward direction.

The motor is a 36 V DC cordless drill motor. Even applied at about half power, it might produce more torque than the one-way needle bearings I ordered.

The drive shaft will go between a pair of wheels on my in-line skates, for a roller drive. There is a limited amount of space between wheels because that's how in-line skates traverse rough terrain. I would like to make an in-line wheel skateboard too (after figuring out how to steer the thing).

Thanks to the replies. I'm just wallowing in the possibilities presented here in this thread. Wish I'd asked/known about spring clutches and needle bearing clutches many months ago.

slight

The ones I'm familiar with have a spring that is a sliding fit on the shaft. The tension / actuating arm puts friction on the free end, winding the spring and grabbing the shaft, so there is quite a size tolerance over which it should work. Just make sure that the spring is loose enough that the shaft doesn't grab in the unwound state, and that the actuator applies enough drag to wind the spring until it does grab.

AWEM

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Unfortunately, I need a one-way needle bearing outer diameter of no more than about 5/8" but a foot pounds rating to suit a 24 to 36 V DC motor. It goes between two in-line skate wheels as a roller drive. I'm kind of planning on doing other similar things with stuff discussed in this thread. But I'll ask further in another thread. Thanks.

Ultra simple (making it easy to build) and plenty of power to the wheels/ground. I might refer to some pictures tomorrow.

Um. Your torque spec as stated isn't useful.

Sounds interesting.