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A receptacle bolted to a tire rim contains retractable vanes inside,
which can be deployed to boost traction.
Using the example of an off-road vehicle which is stuck in the dirtor
snow, with tires spinning and unable to grip - the vanes would
deploy, projecting out of a receptacle bolted the
tire rims, to extend
in a radial direction, giving more traction in the dirt.
A solenoid switch would be used to unlock the vanes to allow them
to deploy. The rapid rotation of the tires would generate the
centrifugal force necessary to ensure the vanes extend fully outward
in a radial direction. Their length when fully extended would be
greater than the radius of the tire.
As soon as the vehicle is free, and tire RPM is slowed down, then
the vanes can be retracted back into the receptacle.
Go ahead and jump to the 3:00 mark. [2 fries shy of a happy meal, Nov 04 2020]
link to image of them [sanman, Nov 04 2020]
[2 fries shy of a happy meal, Nov 05 2020]
||The hub caps would be larger diameter, and that diameter
would exceed the radial thickness of the tire itself, as is
common on many sportier vehicles today.
||To produce traction, the vanes would have to bear the
weight of the vehicle, and would do this by locking into
place, once they have extended out. This would be
accomplished by the rapid rotation of the tires, and the
centrifugal force generated by them. Each vane would
independently extend out and lock into place, as its
particular spot on the tire rotated upward away from the
ground (7 o'clock position onward?)
As the arc-position of each vane rotates upward and away
from the ground, it's free to fully extend outward since it's
not bearing the load of the vehicle.
Once each vane locks into place, then it will stay fully
extended even as its particular spot on the tire rotates to
the load-bearing ground-facing position (5 o'clock position
Thus all the vanes don't extend out and lock in exact
simultaneous unison, but rather in quick succession as they
quickly rotate along the rotational arc of the tire.
The outer portion of each vane would have more mass,
which will help it to catch more centrifugal acceleration to
aid it in extending outwards, and this mass would also
contribute to load-bearing sturdiness.
||Okay, I should have said tire rims - let me revise. What I meant
is that you can have tire rims that are large, while the
surrounding tire isn't that much larger than the rims.
||[kdf] If they're made of a strong alloy, then why would the
vanes break like the wooden post shown by that farm
||Never mind what I said about sport vehicles. I'm talking
about large diameter rims. Surely that's not hard to picture.
And so that large rim-diameter provides ample space in
which to stow the vanes, which can project out to extend
beyond the radius of the tire itself.
||Yes, the vanes would deploy with the wheels slipping -- the
fact that the wheels are slipping is why you're seeking to
deploy the vanes in the first place -- to aid your wheels in
no longer slipping.
||[kdf] - It would be an electronic signal to a solenoid that
would cause the vanes to become available, while the RPM
would then drag them out. Until and unless the solenoid
switches, then no amount of RPM will allow the vanes to
||Many years ago, I remember an article (or possibly an ad...)
in a science magazine for the "static" version of this (Google
was no help finding them...).
Basically it was a (strong) plastic paddle wheel that was
bolted to the wheel (using the normal wheel-hub bolts), to
aid with traction in mud/swamp etc. Not larger than the
tyre diameter, though, so you could drive normally with
them attached. I think they were called "Bog Clogs".
||"Bog Clogs"... hmm... sounds like they were onto something.
See the new link I've attached.
||[kdf]; nice find.
[sanman]; yup, just like that, although I thought they were
smaller (relative to the wheel...).
||That pic is from a Japanese mini-truck, so that's why they
look bigger relative to the vehicle
||Perhaps if the inner portion of the steel wheel, the flared
portion at the lip that retains the tire bead, were flared
more dramatically such that notches could be cut in the
perimeter. Vanes that might sprout from the hubs could
splay across the tire tread and hook into these notches
and then not flail and break.
||This reminds me of a toy from when I was a kid.
||I think there is some confusion caused by regional terminology. When I use "tire" (or "tyre") I mean just the rubber part. The wheel bolts onto the hub. The tyre goes onto the rim of the wheel. When a car gets a flat tyre, I get out the spare wheel - which has a tyre on it. To change a wheel, I use a hub spanner (wrench). To change a tyre, I use tyre levers (irons) and curses. When [sanman] says //tire//, he means wheel.
||4x4's of the 70's and early 80's used to have manual locking
wheel hubs that you turned to engage. This could be
something similar with some sort of cam system to deploy.
||However, the unsprung jounce weight would be horrid. It
would want to be a temporary bolt-on, not a permanent add.