device that applies braking force proportional to speed?

Hi, I'm helping a team of students make a brake-assist device for a two-wheeled walker. 

We were wondering if there are mechanical brakes out there that apply a force proportional to the speed.  A circular damper, is how we would describe it, I think.  Or something like a gas shock (the things on screen doors and car trunks) but with a circular motion rather than a linear stroke.  Anyone have any ideas?  Anything that's commercially available, small, and somewhat inexpensive is fair game.  Bonus points for things that can be made by hand..  Thanks!

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drakesword7 years ago
Or an old school centrifugal ball brake. Look at old elevator safety brakes.
lemonie7 years ago
Electric brakes. AKA "dynamic braking" or "rheostatc braking", or "regenerative braking"

Fit an electric motor/generator, activate by switching it to power an electric heater.

www.trains.com/trn/default.aspx

L
_mattb (author)  lemonie7 years ago
I've heard that idea tossed around; I think we could experiment with it easily.  The trick, as I see it, would be to make it small and light enough that it's not cumbersome.
lemonie _mattb7 years ago
small and light enough that it's not cumbersome.
Electrical generators may weigh a bit, but the electric load-bank could be rather light. Think about clever-mechanical activation (non-human) and I don't think you'd beat "light" by much, if at all. It's simple enough to do today (if you've got the parts)

L

Kiteman7 years ago
A governor that triggers a switch at a certain point?
NachoMahma7 years ago
.  Hold the bell of a centrifugal clutch still and you have a brake.