just another planetary gear unicycle...

Hi!

How long have I been waiting to post this message…

And now it´s just one day after Greg Harpers announcment of the first
panetary gear unicycle. So OK, that´s life: here´s the second!

I´ve been thinking about this since the unicycling across Minnesota
tour (perhaps Andy and Roger remember?) and now work ist finished. 1.5
hours ago I had the great feeling of riding a 26" unicycle geared up
by ratio 1.57 to a 41". It was similar to riding Roger Davis´ Coker
with 102(?) mm cranks at European Juggling Convention 2001 in
Rotterdam. But it is only 6.65 kg.

It is based on the same planetary gear principle like Greg Harper´s
hub (but i have not stolen the idea, I think, my CAD-drawings were
finished before the first posting of Greg here in the newsgroup).

I have put my CAD-drawings, pictures of the finished unicycle and two
short videos (!) on my homepage. But for the avi files you need divx4
codec. You can download it from http://www.divx.com/divx/

OK, I hope you can access this page and watch the avis´s

That´s my homepage:

<a href="http://people.freenet.de/unifrank/index_engl.htm">http://people.freenet.de/unifrank/index_engl.htm</a>

There are also some pictures of the unicycle tour across greece,
September 2000. That was a unsupported (no support vehicle) tour from
Thessaloniki to Athens (we rode 540km). I made this tour with Sven
Wittorf and Erik Kolb (he´s the one with the recumbent unicycle on
Been there, done that) Great fun!

By the way: I just wrote about geared unicycles on Been there, Done
that…

Shouldn´t there be two more names now???

CU!

Unifrank

Awesome. Any plans for mass-production? :slight_smile:

Frank-

VERY cool. And with a larger wheel and higher gear ratio. Your videos are like looking at things I have ridden and held in my hands.

Did you measure the pedal backlash? If so, how much?

I know you had planned to use more aluminum than me. What is the final weight of your hub?

Did you use the design approach that you wanted to keep secret or is this a standard planetary gear approach?

Beautiful machine work. Did you do it yourself? Are there any welds?

Do you find it awkward to freemount, like a Coker?

Congratulations on what is obviously a successful project.

Es ist zer schnell?

Hi Frank,

Great to see you are there with your hub, you will be a beast with that!
you were bad enough with your 28".

My Coker only has 110mm cranks on it at the moment, I have 102 to put on it
but have not got around to doing it yet, has anyone tried it yet? I have
had 50mm cranks on but that was silly and only for 100m and I didn’t do it,
Miark did it to my Coker when I wasn’t looking. :slight_smile:

Roger


The UK’s Unicycle Source
http://www.unicycle.uk.com


----- Original Message -----
From: “Unifrank” <einrad@epost.de>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Wednesday, February 20, 2002 9:20 PM
Subject: just another planetary gear unicycle…

> Hi!
>
> How long have I been waiting to post this message…
>
> And now it´s just one day after Greg Harpers announcment of the first
> panetary gear unicycle. So OK, that´s life: here´s the second!
>
> I´ve been thinking about this since the unicycling across Minnesota
> tour (perhaps Andy and Roger remember?) and now work ist finished. 1.5
> hours ago I had the great feeling of riding a 26" unicycle geared up
> by ratio 1.57 to a 41". It was similar to riding Roger Davis´ Coker
> with 102(?) mm cranks at European Juggling Convention 2001 in
> Rotterdam. But it is only 6.65 kg.
>
> It is based on the same planetary gear principle like Greg Harper´s
> hub (but i have not stolen the idea, I think, my CAD-drawings were
> finished before the first posting of Greg here in the newsgroup).
>
> I have put my CAD-drawings, pictures of the finished unicycle and two
> short videos (!) on my homepage. But for the avi files you need divx4
> codec. You can download it from http://www.divx.com/divx/
>
> OK, I hope you can access this page and watch the avis´s
>
> That´s my homepage:
>
> http://people.freenet.de/unifrank/index_engl.htm
>
> There are also some pictures of the unicycle tour across greece,
> September 2000. That was a unsupported (no support vehicle) tour from
> Thessaloniki to Athens (we rode 540km). I made this tour with Sven
> Wittorf and Erik Kolb (he´s the one with the recumbent unicycle on
> Been there, done that) Great fun!
>
> By the way: I just wrote about geared unicycles on Been there, Done
> that…
>
> Shouldn´t there be two more names now???
>
> CU!
>
> Unifrank
>


> rec.sport.unicycling mailing list -
www.unicycling.org/mailman/listinfo/rsu

Nice one Frank,
Very honourable of you not to steal Harpers thunder!

Cool animations.

Are you bringing your beast to Unicon and/or Eurocycle?

Hmm - the unlimited racing stakes are hotting up I’d like to see you riding
against short-cranked Cokers and Harpunis!

Leo

On Wed, 20 Feb 2002 22:08:07 +0000 (UTC), AccordNSX
<forum.member@unicyclist.com> wrote:

>Awesome. Any plans for mass-production?

Ask me another day. Not after a week of thinking in 1/100mm. It´s such
a lot of work to build such a hub. But on the other hand: I have used
parts for the gears which are quite easy to get. They are from a
shimano 7-speed-hub which i found on a flea marked for about 7 EUROs
(a bit more in dollars, but not much more). I think the shift
mechanism was broken. But i was only interested in the gears. Within 2
months I got 2 other hubs of the same type. And when I asked for some
special parts in a bike shop I saw two of these hubs (used) in a box,
they had been replaced. So it´s no problem to get the gears. The ball
bearings cost about 45 EUROs. Then you need a normal unicycle hub and
someone who can machine some very exact steel and aluminium parts.

The mechanic who made these parts for me said that it would be not
much more work to build 5 instead of 1 part (when the machine is set
up for one part you can easily make another one). But before you all
send your orders: This one has been made to be demonstration object
for our institute (I´m working at a university) and there will be no
mass-production. But if there is anybody else who wants to produce
such a hub, I can send him the drawings.

UniFrank

On Wed, 20 Feb 2002 22:18:06 +0000 (UTC), harper
<forum.member@unicyclist.com> wrote:

>Frank-

>VERY cool. And with a larger wheel and higher gear ratio.
>Your videos are like looking at things I have ridden and held in my
>hands.

I know!

>Did you measure the pedal backlash? If so, how much?

There is some, it is less than 1mm at the pedal on 150mm cranks. You
feel it when you ride but there are no problems at all.

>I
>know you had planned to use more aluminum than me. What is the final
>weight of your hub?

It was 1.246 kg without the outer (6203) ball bearings and the part
that connects to the fork. so the complete hub (6203 are 65.4 g each)
should be less than 1.5 kg.

>Did you use the design approach that you wanted
>to keep secret or is this a standard planetary gear approach?

The secret what I wanted to keep was using parts from a shimano inter
7 hub. It seems very easy to get used (with broken shift mechanism?)
ones here. It´s jest the same planetary principle that you used.

>Beautiful machine work. Did you do it yourself?

No, I´m working at a university institute and the steel and aluminium
parts werde made by our experienced machanics.

>Are there any welds?

No, none at all!!!

>Do you find it awkward to freemount, like a Coker?

I just had 5 rides in the building (it´s night in germany and it´s
raining) then I started to set up the homepage. And i didn´t try to
freemount. I thought i could never ride it when i first got on this
one but it felt familiar after 2 minutes. I surely will be able to
freemount but it feels very similar to a coker with short cranks.

>Congratulations
>on what is obviously a successful project.

Back to you! You were the first!

>Es ist zer schnell?

Oh ja, verdammt (damned, f***ing,…) schnell! :wink:

UniFrank

On Wed, 20 Feb 2002 22:32:28 GMT, “Leo White” <leo.white@tesco.net>
wrote:

>Nice one Frank,
>Very honourable of you not to steal Harpers thunder!
>
>Cool animations.

Thanks!

>Are you bringing your beast to Unicon and/or Eurocycle?

No/yes. I will not go to Unicon but I will definitely be at Eurocycle.

>Hmm - the unlimited racing stakes are hotting up I’d like to see you riding
>against short-cranked Cokers and Harpunis!

I would really love to do the 10k unlimited but the flights are really
expensive.

CU in Bremen!

UniFrank

I would like to see detailed drawings if you have them readily available. Can they be posted on your web site? I think you mailed me some sketches in the past, but not dimensioned drawings. I can view AutoCAD r14 dwg files.

Thanks. Let’s get together and race these things. Or maybe hire jockeys to race them for us.

On Wed, 20 Feb 2002 22:48:56 GMT, einrad@epost.de (Unifrank) wrote:

>On Wed, 20 Feb 2002 22:18:06 +0000 (UTC), harper
><forum.member@unicyclist.com> wrote:
>
>>Frank-

...

>>Do you find it awkward to freemount, like a Coker?
>
>I just had 5 rides in the building (it´s night in germany and it´s
>raining) then I started to set up the homepage. And i didn´t try to
>freemount. I thought i could never ride it when i first got on this
>one but it felt familiar after 2 minutes. I surely will be able to
>freemount but it feels very similar to a coker with short cranks.

Update on this one: I have just taken this beast to try freemounting.
The 3rd attempt succeeded and now it´s no problem at all.

>UniFrank

On Wed, 20 Feb 2002 22:48:56 GMT, einrad@epost.de (Unifrank) wrote:

>On Wed, 20 Feb 2002 22:18:06 +0000 (UTC), harper
><forum.member@unicyclist.com> wrote:
>
>>Frank-

...

>>Do you find it awkward to freemount, like a Coker?
>
>I just had 5 rides in the building (it´s night in germany and it´s
>raining) then I started to set up the homepage. And i didn´t try to
>freemount. I thought i could never ride it when i first got on this
>one but it felt familiar after 2 minutes. I surely will be able to
>freemount but it feels very similar to a coker with short cranks.

Update on this one: I have just taken this beast to try freemounting.
The 3rd attempt succeeded and now it´s no problem at all.

>UniFrank

Frank-

If there are no welds, I am very interested in the sun-gear-to-sun-cage connection and the axle-to-planet-cage connection. If you have success with some kind of press fit or keyed fit I would like to try to reproduce those joints. My axle-planet-cage is machined from one piece of steel and that operation could be simplified greatly if a press fit works. It also would have eliminated the problem I had locating the planet shaft holes. My sun gear assembly is welded and I would like to eliminate that weld.

I just took my (I’m trying to think of names here…uni.5?) for the 3 mile ride I generally take on my Coker. The uni.5 was every bit as fast and much more responsive and noticeably lighter than the Coker. There is a very steep hill climb on the ride so I got to stress it going up and down and nothing loosened up or got damaged. The ride with the 24x2.125 Kenda tire was no where near as cushy or comfortable as the Coker. The esthetic appeal was much less with no mouths agape at the sight of a GIANT wheel. No one seemed to know that there was a geared hub inside.

But…ja ist zer schnell…ich kochen mein Unterwasche!!

Ya gotta love the banter, and feel a little jelous being on the outside: two mad scientists discussing re-animation.

Greg: How did you gauge when to cut the flow of electricity to the cerabellum?

Frank: A hamster is used as a fuse. Did you use the old kite-and-lightning thing for power?

Greg: Why? I’v got kids. They took turns pedaling the generator. Can it say your name yet?

Frank: Almost. It tends to mumble the ‘enstien’ part, though…

Christopher

I don’t have kids any more. I’ve got adults. My youngest is 21.

You guys blow me away more and more everyday. One of these days I’ll have a Unicycle breakthrough that the whole community can benefit from. Now this is where one of you becomes smart and patents the damn thing.

On Wed, 20 Feb 2002 23:07:57 +0000 (UTC), harper
<forum.member@unicyclist.com> wrote:

>I would like to see detailed drawings if you have them readily
>available. Can they be posted on your web site? I think you mailed me
>some sketches in the past, but not dimensioned drawings. I can view
>AutoCAD r14 dwg files.

The files are AutoCAD 2000 with Mechanical Desktop. I don´t know if
you can open these files in r14. I can mail you these files and you
can check it out. But now I will drive home and go to sleep :wink:

CU!

UniFrank

Re: just another planetary gear unicycle…

On Thu, 21 Feb 2002 01:18:02 +0000 (UTC), harper
<forum.member@unicyclist.com> wrote:

>Frank-

>

>If there are no welds, I am very interested in the sun-gear-
>to-sun-cage connection and the axle-to-planet-cage connection. If you
>have success with some kind of press fit or keyed fit I would like to
>try to reproduce those joints.

I have added two pictures of these parts on the homepage. The first is
the part which connects the axle to the planet cage. The connection to
the axle is a press fit and the connection to the planet cage provided
by the shape of 12 notches (?) and 3 screws.

The second picture shows the part that hols the sun pinion (which has
a saw-teethed inner surface). It is firmly pressed onto and locked by
a (seeger-) ring.

UniFrank

The sawtooth sun gear of course looks like it was designed for engagement in one direction only. This would make sense because it is from a bicycle hub. Have you tried pedaling it backwards?

What is a seeger ring?

The planet cage engagement piece looks really strong. Was it difficult to machine? It looks a little complex to manufacture.

Re: just another planetary gear unicycle…

On Thu, 21 Feb 2002 10:00:27 -0600, harper
<harper.fmyy@timelimit.unicyclist.com> wrote:

>What is a seeger ring?
It’s almost the same as a snap ring that you have on your axle as
well. The only difference afaik is that a snap ring has a constant
radial width, whereas a seeger ring is thicker in the middle and
thinner towards the ends, so that it deforms in a circular manner when
stressed. But I’m not sure if this distinction is always adhered to.

Klaas Bil

“To trigger/fool/saturate/overload Echelon, the following has been picked automagically from a database:”
“KMI, Plutonuim, black-ops”

Re: just another planetary gear unicycle…

On Thu, 21 Feb 2002 10:00:27 -0600, harper
<harper.fmyy@timelimit.unicyclist.com> wrote:

>
>The sawtooth sun gear of course looks like it was designed for
>engagement in one direction only. This would make sense because it is
>from a bicycle hub. Have you tried pedaling it backwards?

That´s true, the inner teeth of the sun gear only work in one
direction in the bicycle hub. But the part which it is pressed on in
my hub has the exact negative shape of this geometry. And it is a very
firm press fit. I tried to use a hydraulic bench vice with a maximum
power of 40 kN (4 tons) and it was not enough to slide the sun pinion
onto the connecting part completely. I then used a big mechanical
vice. So it won´t move a bit.

And by the way: when I first attached the wheel to the fork I didn´t
pay attention to the direction. So right now I´m riding in the
“backward” direction.

>What is a seeger ring?

See posting by Klaas. He´s right.

>The planet cage engagement piece looks really strong. Was it difficult
>to machine? It looks a little complex to manufacture.

Yes, it is quite complex. The shape was done with a 6mm milling tool.
The more complex parts of the hub were practised as aluminium
prototypes before they were finally manufactured as steel parts. And:
no CNC was used at all, just exact manual machining.

Greg, what crank size do you use? Yesterday my 150mm cranks felt way
too long so I changed to 125mm. I didn´t ride it up to now and I´m
very curious about which will be the minimum in crank size. And I will
attach a speed computer :wink:

UniFrank