> New idea for a group trick! A group of, say, six auto-giraffers ride in a > circle. Then everyone gets launched synchronously. While airborne, the unis > continue in a circle such that the riders come down on the next uni in line, > until the riders finally get back “home”. And so is born "Unicycles juggle > riders!"
I thought this was funny enough to send to some friends. Here is the reply
from one of them:
:Well there is also one more alternative. For example those riders who :are not
going fast enough can probably use the new curry patent formula. :It involves
going out for an exceedingly hot madras - you know the kind. :Once back eat some
fart pellets. Use the new space shuttle toilet seat :idea and connect the output
to a jet engine. :When the jugglers are in the air let them have an automatic
firing :mechanism so that they can jump even higher. The mechanism could take :the form of a lighted match (easy to do). Then we could have some mega :giraffes and hey presto - orbiting jugglers! :Erm sorry danny and everyone
else. Had to be said. Please send all mail :via a Akuma. :Cheers : :±-------------------------------------±-------------------------------------+ Mail from : Enigma | E-mail : py3mwl@midge.bath.ac.uk | :±-------------------------------------±-------------------------------------+ Everybody should believe in something - I believe I’ll have another drink. | :±----------------------------------------------------------------------------+ Life is a sexually transmitted disease, and it is 100 per cent fatal | :±----------------------------------------------------------------------------+
A shaft drive unicycle sounds like it would have some advantages, but I would
have to agree that it would probably end up being fairly heavy.
>My thought, although I hadn’t written it “out loud”, was to use very light >metals, such as aluminum for the shaft, and rather small gears, for exactly >that reason
Small, light aluminum gears would be nice, but would they stand up to the load
placed on them? Your legs can put out a pretty decent amount of torque and a
unicycle wouldn’t be much good if you had to worry about stressing the gears all
the time. Even if the gears did stand up initially, the aluminum would probably
wear fairly quickly and there go the tight tolerances somebody mentioned you
would need. There’s also the occasional collision with the ground.
> >My thought, although I hadn’t written it “out loud”, was to use very light > >metals, such as aluminum for the shaft, and rather small gears, for exactly > >that reason > > Small, light aluminum gears would be nice, but would they stand up to the > load placed on them? Your legs can put out a pretty decent amount of torque > and a unicycle wouldn’t be much good if you had to worry about stressing the > gears all the time. Even if the gears did stand up initially, the aluminum > would probably wear fairly quickly and there go the tight tolerances > somebody mentioned you would need. There’s also the occasional collision > with the ground. > > Alec
Alec,
Although I didn’t spell it out, I meant aluminum for the shaft only, steel for
the gears, for the reasons you mention.
How about a composite unicycle? If some of the major components of the unicycle
such as the frame or seatpost were made of fiberglass (or carbon fiber) you
might be able to achieve a significant weight reduction. This might make up for
some extra weight in the drivetrain.
Also, perhaps a small unicycle, say with a one foot shaft, as a proof of concept
model. If it worked well you could then go on to bigger and better unicycles…
> > “Unicycles juggle riders!” > > I thought this was funny enough to send to some friends. Here is the reply > from one of them: > > :Well there is also one more alternative. For example those riders who :are > not going fast enough can probably use the new curry patent formula. :It > involves going out for an exceedingly hot madras - you know the kind. :Once > back eat some fart pellets. Use the new space shuttle toilet seat :idea and > connect the output to a jet engine. :When the jugglers are in the air let them > have an automatic firing :mechanism so that they can jump even higher. The > mechanism could take :the form of a lighted match (easy to do). Then we could > have some mega :giraffes and hey presto - orbiting jugglers! :Erm sorry danny > and everyone else. Had to be said. Please send all mail :via a Akuma. :Cheers > : > :±----------------------------------±-------------------------------------+ > Mail from : Enigma | E-mail : py3mwl@midge.bath.ac.uk | > :±----------------------------------±-------------------------------------+ > Everybody should believe in something-I believe I’ll have another drink. | > :±-------------------------------------------------------------------------+ > Life is a sexually transmitted disease, and it is 100 per cent fatal | > :±-------------------------------------------------------------------------+
As they used to say back in the 50’s, “Now you’re cookin with gas!”
> >I’m looking forward to people’s reactions. Is this feasible? Is it desirable? > >What do you think? > > >> Mark > > cient for transmitting power) > > Toothed gears of any kind must be machined ultra precise to avoid backlash. > > The other drawback I can think of is inertia. Since a shaft drive with > beveled gears at each end will be heavier, it will be harder to change from > forward ped > > Dennis Kathrens >
I get your drift, Dennis. (I think, anyway - I lost part of your lines due to
different line lengths or something in your email).
My thought, although I hadn’t written it “out loud”, was to use very light
metals, such as aluminum for the shaft, and rather small gears, for exactly that
reason. But I’m not terribly worried about it because if you’ve ever held a
chain and sprockets, you know they’re not feathers. And the weight of giraffes
is very variable, too, based on materials and design differences.
But yeah, gear lash and the cost of eliminating it could be a show stopper, even
if weight isn’t. Still, it might be interesting to do one, even if it’s
flawed, as a proof-of-concept (or disproof, as the case may be). And there
again, with people riding various bizarre constructs like
2.5 wheel giraffes, maybe a little gear lash isn’t the end of the world?
BTW, sorry I’ve been off-line for a few days - busy at work, ya know. I’ve been
scribbling on napkins, playing with ideas. I’ve got a few, but I’m still
sketching. Keep those “cards and letters” coming!
Mark Schecter <schecter@tfs.com> wrote: >What would be the point of converting to shaft drive? To reiterate the original >idea, it was to allow variation in the distance between crank and wheel axle >(with a splined connection between two parts of the shaft), so that bouncing on >the seat could compress a spring without changing the distance from the seat to >the pedals. > >Frankly, I think that is insufficient reason to go to all the trouble of >converting to shaft drive. > >However, I’m wondering, would there be some other advantages in converting to >shaft drive (without multiple gears)? I’ll list some thoughts for yer-alls’ >reactions: > >Shaft drive would have these advantages: > > * eliminate chain stretch > * clean up the giraffe, reducing external grease > * look better > * might be less vulnerable to damage when (if!) dropped > * might make gearing changes easier (static, not on-the-fly) > * might provide a path to multiple gears (later!) > * can you think of others?
Yes! Would not get caught in pants!!!
>On the other hand, shaft drive would have these disadvantages: > > * requires developing the mechanism, not exactly a trivial task > * might be heavier > * because it’s different from bicycle parts, it could cost more > * might have problems with free play/gear lash, in other words, > slop in the transition from pushing to pulling. > * can you think of others? > >I’m looking forward to people’s reactions. Is this feasible? Is it desirable? >What do you think?
Old bicycles, around the turn of the century or 1980’s, used shaft drive. I’ve
seen them ridden in shows in recent years, so they must work. The same
technology might work for a giraffe. A limited amount of “slop” in the drive
system is acceptable, as many riders of Schwinn Giraffes may be familiar. If
your crankshaft clicks back and forth in that little hole in the top sprocket,
you know what I’m talking about, and you also know it’s not anything to stop you
from any kind of riding.
Somebody should build one of these things!
John Foss, President International Unicycling Federation unifoss@cerfnet.com
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