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fun in the snow
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Friction Inducing Bearing?

03/06/2012 9:41 AM

Looking for a means of providing rotational friction to a 1" shaft rotating aprox. 40 rpm. It has to provide aprox 2 ft/lbs of friction(torque) in either direction

Thanks
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Crabtree
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#1

Re: friction inducing bearing?

03/06/2012 9:48 AM

A "brake", then?

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fun in the snow
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#2
In reply to #1

Re: friction inducing bearing?

03/06/2012 9:55 AM

thought of it but would not stand up to 12 hr day - 7 day week use :(
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Mikerho
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#4
In reply to #2

Re: friction inducing bearing?

03/06/2012 10:04 AM

Yes it would. They are used all the time in web-based manufacturing. It is a way of controlling tension. Here are some pneumatically actuated brakes:

http://www.rmhoffman.com/distribution_products/pneumatic_hydraulic_brakes_clutches/

and some electromagnetic brakes:

http://www.rmhoffman.com/distribution_products/electromagnetic_brakes_clutches/

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lyn
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#6
In reply to #4

Re: friction inducing bearing?

03/06/2012 10:36 AM

Why didn't I think of that? Used to do a lot of work with Sheldahl, among others.

GA.
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Crabtree
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#5
In reply to #2

Re: friction inducing bearing?

03/06/2012 10:05 AM

Well, you might have put that in the original posting.

2ft.lb x 40rpm x 2π radian per revolution ≈ 500ft.lb/min or most of a horsepower. Easy-peasy.

Are you going to say what this shaft does or are the rest of us to be kept in the dark or something?

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fun in the snow
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#7
In reply to #5

Re: friction inducing bearing?

03/06/2012 10:38 AM

sorry for the lack of info - what i am doind is having multiple shafts, that are mounted on a reel, follow a cam via a cam arm and follower. reel is travelling at 40 rpm. shaft on reel is travelling in opposite direction but i need some way to control the wild rotaional rattle caused by the cam follower having to leave the cam in two lacations in its rotation( its over center rotations). have developed the use of a belt system and a pulley mounted on the shaft to provide with adequate frition( via belt slipping on th pulley) but found that i am gaining too much variance as the belt wears or gets wet :(.
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lyn
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#8
In reply to #7

Re: friction inducing bearing?

03/06/2012 10:41 AM

Check out Mikerho's suggestion. I've seen web machines that run around the clock for 5 or even7 days a week.

Back when times were better, I should say.
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Codemaster
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#9
In reply to #5

Re: friction inducing bearing?

03/06/2012 12:32 PM

No, a horsepower = 550 ft.lb/s, 33000 ft.lb/minute'

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Crabtree
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#10
In reply to #9

Re: friction inducing bearing?

03/08/2012 3:40 AM

Ooops! Sorry. I'm better used to working in metric.

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Doorman
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#3
In reply to #1

Re: friction inducing bearing?

03/06/2012 9:59 AM

What ho! I think you've got it, old bean. A technology brakethrough!

[edit] Maybe a brake of the magnetic variety?

[edit again] What other secret criteria are there to consider?

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Codemaster (1); Crabtree (3); Doorman (1); fun in the snow (2); lyn (2); Mikerho (1)

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