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Chain Wheels

Circle of chain, "centrifugal force", off-road travel.
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Chain wheels are off-road dune-buggy wheels made like spoked bicycle wheels, with the rim and tire replaced with a circle of heavy chain. Instead of spokes, there is a series of lighter-weight chains that lead from the outer chain through an arrangement of holes in the two hub flanges, as is done with bike spokes. The big difference is that the spoke chains attach to a take-up reel built into the hub, so they can be retracted. The two rim flanges of the hub are fitted with narrow rubber tires for low speed travel.

An off-road vehicle equipped with chain wheels starts off driving on the rubber of the rims, with the spoke chains retracted and the slack sections of the rim chain flopping around. As it picks up speed, the slack of the rim chain is thrown outward by inertia. As speed increases, the centrifugal inertia of the upper portions of the rim chain lifts the wheel hub off the ground. The spoke chains are let out by the reel, and the outer chain assumes a more circular shape.

At top speed, the chain is fully circular, except for the part hitting the ground. The vehicle has raised up, supported by the centrifugal inertia of the chain opposite the ground, transferred through the spoke chains to the hub. The spoke chains, leading to the two sides of the hub, also give side-to-side stability, and allow the vehicle to turn slightly.

The rim chain flexes over obstacles, and provides suspension. The links give plenty of traction. The wheel doesn't collapse under slight braking and cautious turns, and only hangs up when something goes over the rim chain and into the spokes.

An off-road vehicle equipped with chain wheels is a bugger to maintain, hard to operate, unstable, noisy, unsafe to be in or around, and tears up the ground something fierce. Even better, it looks like a formation of flying buzz saws.

baconbrain, Sep 21 2006

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       Interesting.
BJS, Sep 21 2006
  

       Well, this will certainly be higher-impact than the current dune buggies and ATVs that people use to tear up dunes and muddy fields...   

       The inherent danger in using such a device leads me to suspect that part of the intent is to use natural selection against such recreational drivers...
ye_river_xiv, Sep 21 2006
  

       Reminds me of those machines used for clearing minefields. I'm not sure this would work unless you had really massive chains or were moving really fast, but anything involving rattling, unsafe, and most likely impossible technology gets my vote!
discontinuuity, Sep 22 2006
  

       The speed needed to have a centrifugal force big enough to keep the entire car off the ground would be much greater than any speed a dune buggy could achieve. But the idea of having slack chains on wheels is good. The chains would provide better traction on low-traction terrain like sand or mud. There are snow chains, why not have sand chains? And I love the mental image of a formation of flying buzz saws tearing across a sandy beach landscape. A bun to your idea.
Veho, Sep 22 2006
  

       I wonder where you acquired your unfounded faith in centrifugal force.
monk, Feb 25 2007
  

       //The rim chain flexes over obstacles, and provides suspension.// The centrifugal force is sufficient to support the weight of the vehicle, no? So, I don't see that there is any difference (in this respect) from a pneumatic tyre - the support provided by centrifugal force is just the equivalent of pneumatic pressure.
MaxwellBuchanan, Feb 25 2007
  

       //I wonder where you acquired your unfounded faith in centrifugal force.//   

       In a monastery in Tibet, after spending a month living inside a giant prayer wheel.
baconbrain, Feb 25 2007
  

       Hahah...I like that one, brain. Maxwell, I don't think any of us have proof whether this will work or not, so I feel a twinge of regret for saying that. From my standpoint, it is a theoretically but not applicably possible concept.
monk, Feb 26 2007
  

       I think this would work just fine, and as [baconbrain] says, tear up the countryside even more effectively than current 4x4s.   

       It would need a lot of power to get up to cruising (full circle wheels) speed, but once there it would probably be reasonably economical (as 4x4s go, anyway).   

       What's holding the vehicle up isn't really "centrifugal force", it's the inertia of the links of the chain as the radial chains pull them down at the top of their orbit - there's no matching downpull because the bottom links are pushed up by the ground, not pulled up by the radials.   

       But centrifugal force is real and very powerful, popular myth to the contrary notwithstanding - in rotating frames of reference. It's only in non-rotating frames of reference that it's fictional.
Cosh i Pi, Apr 18 2007
  

       Picture?
bungston, Apr 19 2007
  

       Ever realised you were experiencing a tyre breakdown while driving at speeds of more than 100 km/h? If yes, how?
sweet, Apr 19 2007
  

       [sweet] Yes. Tyres aren't usually massive enough to support the weight of a car on the inertia of the treads.
Cosh i Pi, Apr 19 2007
  

       [bigsleep] That was roughly what I did in my head, without actually plugging any numbers in. Anyway, I've seen cars having tyre breakdowns at speed, apart from experiencing it myself a couple of times. You don't get as clear a picture from inside the car, though, and your mind tends to be on other things anyway.   

       [edit] I doubt the treads of your tyres weigh 20kg apiece on a car weighing 1000kg. A quick Google suggests 7-8kg would be nearer the mark.   

       [baconbrain] did say "heavy chains", without putting numbers on it - and clearly if the chains were heavy enough, it would work. Exactly how heavy, I too will leave to someone else. I can't be bothered.
Cosh i Pi, Apr 19 2007
  

       [bigsleep] The other important factor is that unless the road is incredible smooth and even, the force of the car down on each wheel varies rapidly by quite substantial amounts. Even at speeds you might expect to ride on the inertia of the treads, you'll actually hit the rims repeatedly. This is what you feel.   

       In practice of course the tread itself rapidly breaks up once the pressure goes, and anyway the sidewalls lose the ability to keep the tread in line with the rims.
Cosh i Pi, Apr 19 2007
  
      
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