Suspension MUni

Discussion in 'rec.sport.unicycling archive' started by Pete66, Jul 5, 2004.

  1. Rayden

    Rayden Guest



  2. I like the idea of having the bands arranged as spokes,
    because it would undoubtedly be a lot lighter, and probably
    cheaper, but I can see that the rim would move side to side
    a lot as well.

    John, hope the exam went well.

    --
    theamazingmolio - A Unicylist, a juggler, and a prat

    Luke Duller ([email protected])
    Never trust anything you read on the internet
    ------------------------------------------------------------------------
    theamazingmolio's Profile: http://www.unicyclist.com/profile/5931
    View this thread: http://www.unicyclist.com/thread/32510
     
  3. Rayden

    Rayden Guest

    Ken Cline wrote:
    > *"Rayden"
    > <[email protected]> writes:
    >
    > > Ok here is a question. Shock absorber versus spring. We
    > > have all
    > been
    > > assuming shocks would be better but why? There has to be
    > > a reason.
    > Of
    > > course we could build a protype of each and see but I
    > > dont think
    > that is
    > > going to happen.
    >
    > I don't think dampers are a good idea. First, after
    > compression during a drop, dampers would tend to make the
    > wheel roll unevenly (eccentrically). Second, work dont on
    > the damper would be wasted energy.
    >
    > Ken *

    If you have a spring you need some kind of damper i think.
    If not you would just bounce forever. Possibly your legs
    would do the dampening and you wouldn't need them. I think
    this is getting to the point where the answers will only
    come from building one and testing.

    --
    Rayden
    ------------------------------------------------------------------------
    Rayden's Profile: http://www.unicyclist.com/profile/264
    View this thread: http://www.unicyclist.com/thread/32510
     
  4. Nickjb

    Nickjb Guest

    Ken Cline wrote:
    > * ... Second, work dont on the damper would be
    > wasted energy.
    >
    > Ken *

    This arguement is used against using suspension in mountain
    biking but I know from my own experience and from the racing
    world that overall it saves energy.

    --
    nickjb - one wheel short
    ------------------------------------------------------------------------
    nickjb's Profile: http://www.unicyclist.com/profile/1074
    View this thread: http://www.unicyclist.com/thread/32510
     
  5. Thinuniking

    Thinuniking Guest

  6. Napalm

    Napalm Guest

    Right, firstly Rayden the amount of time you put into all
    your wonderful diagrams is admirable, and the ideas behind
    them bloddy excellent. I was just thinking, if the uni would
    only be good for dropping etc as said before somewhere
    wouldnt it be easier to make suspension cranks- like semi
    bendy ones. I realise that a suspension seatpost would be
    nesecarry otherwise there goes fathers day. Well my ideas
    from the land of ignorance, Keep up the awesome work, Mark

    --
    napalm - unicycle trampolinist

    all you have to do to learn to fly is to throw yourself at the ground
    and miss
    ------------------------------------------------------------------------
    napalm's Profile: http://www.unicyclist.com/profile/3952
    View this thread: http://www.unicyclist.com/thread/32510
     
  7. Ken Cline wrote:
    > *First, after compression during a drop, dampers would
    > tend to make the wheel roll unevenly (eccentrically).
    > Second, work dont on the damper would be wasted energy.*
    It wouldn't be a huge amount of damping. If it was just a
    spring, then as soon as you hit a small bump you'd just be
    bonucing up and down almost constantly, which would be a
    bit disconcerting and it would mean the wheel would be
    eccentric a lot of the time. The shock absorbers just
    absorb the energy of the spring, so that the spring
    compresses on drops / bumps then extend back to original
    length and stay there, without wobbling. (or suppressing
    the 2nd order oscillatory term of the control equation,
    just to sound posh)

    The shock absorbers might waste some energy from pedalling
    if they weren't quite set up right, so thatsome of the
    springs where slightly compressed while riding. Mainly
    they would absorb the forces from dropping which otherwise
    you have to absorb through rolling out, collapsing your
    body, etc.

    Bendy cranks sound like a recipe for falling off lots,
    although it might be fun to try.

    The other thought that has occured for Rayden's idea is that
    with it being a parrallelogram there's nothing stopping you
    from having 2 or more of these, which might make the wheel
    stronger / stiffer in the rotational direction.

    John

    P.S. The exam went fine, cheers. It was digital electronics,
    it's just 's and 1's, right?

    --
    johnhimsworth - Nullus Anxietas

    What if the hokey cokey really is what it's all about?
    ------------------------------------------------------------------------
    johnhimsworth's Profile: http://www.unicyclist.com/profile/1788
    View this thread: http://www.unicyclist.com/thread/32510
     
  8. Carjug

    Carjug Guest

  9. Rayden

    Rayden Guest

  10. Rayden

    Rayden Guest

  11. Rayden

    Rayden Guest

    napalm wrote:
    > *Right, firstly Rayden the amount of time you put into all
    > your wonderful diagrams is admirable, and the ideas behind
    > them bloddy excellent. I was just thinking, if the uni
    > would only be good for dropping etc as said before
    > somewhere wouldnt it be easier to make suspension cranks-
    > like semi bendy ones. I realise that a suspension seatpost
    > would be nesecarry otherwise there goes fathers day. Well
    > my ideas from the land of ignorance, Keep up the awesome
    > work, Mark *

    Bendy cranks... You can do the design on those. I don't see
    any use for them.

    johnhimsworth wrote:
    > * The other thought that has occured for Rayden's idea is
    > that with it being a parrallelogram there's nothing
    > stopping you from having 2 or more of these, which might
    > make the wheel stronger / stiffer in the rotational
    > direction.*

    Good point. I added a model of that. Looks really funky but
    I don't see why it wouldn't work.

    --
    Rayden
    ------------------------------------------------------------------------
    Rayden's Profile: http://www.unicyclist.com/profile/264
    View this thread: http://www.unicyclist.com/thread/32510
     
  12. Pete66

    Pete66 Guest

    What exactly are you considering getting a patent for?
    With talk like that, I'm starting to feel kinda glad I
    didn't post the 3d models and animations of my 100%
    working version!

    Pete

    PS this thread has become an epic!

    --
    pete66 - Level 4 Unicyclist
    ------------------------------------------------------------------------
    pete66's Profile: http://www.unicyclist.com/profile/4812
    View this thread: http://www.unicyclist.com/thread/32510
     
  13. Rayden

    Rayden Guest

    Like I said I don't know anything about getting a patent.

    I may be naive but if you can prove you had the idea first
    no one else can patent it. So if you were to show us it
    would still be your idea, unless someone else showed they
    had thought of it before you.

    I'm not sure I want to patent it. I prefer to think about
    such things with other people. I certainly wouldn't want to
    come up with a great idea and then have no one do anything
    with it because I had the patent and I didn't do anything.

    --
    Rayden
    ------------------------------------------------------------------------
    Rayden's Profile: http://www.unicyclist.com/profile/264
    View this thread: http://www.unicyclist.com/thread/32510
     
  14. Johnfoss

    Johnfoss Guest

    I don't know if it's different from country to country, but
    I think patent applications usually (or used to) require a
    working model of the idea (assuming it's for something you
    can build a model of).

    Though one person might get the basic idea in their head,
    another person might be the one to actually build it, then
    do all the tweaks and rethinks necessary to get it to
    finally work. Who deserves the credit then?

    An example of this is the Unicycling Society of America.
    Charlotte Fox Rogers (one of the charter members)
    indicated to Bill Jenack in a letter in the late 60s that
    this would be a good idea. Bill started the organization
    in 1973. He gets the credit. Though somebody else may have
    thought of the idea years before, she didn't do the work
    to make it happen. Plus Bill may have thought of it 10
    years before that.

    Same applies to selling unicycles online. I thought that
    would be the best way to get quality products to people with
    actual useful information about unicycling. But I didn't do
    it. When John Drummond contacted me in early 1999 about
    doing it, I jumped all over the idea and offered to help.
    But he did all the work, and deserves all the credit.

    The parallelogram idea looks interesting, but I'm not sure
    how those parallelograms are supposed to work. Do they
    eliminate the problem of windup?

    So far, suspending the axle within the wheel looks like a
    fascinating engineering challenge, but I don't see us
    getting to a solution that doesn't weigh as much as several
    Coker wheels. To combine the shock-absorbing abilities with
    the necessary lateral and drive-direction stiffness, it
    seems like lots of materials will be required.

    So, at risk of taking this already-long post in a different
    direction, how about we use some kind of conventional
    suspension on the wheel, and run the pedals off a drivetrain
    that can compensate? In other words, keep the pedals on
    either side of the wheel, but have the wheel suspended. This
    would still probably be quite a bit heavier than a normal
    wheel, but might be easier to figure out mentally without
    building working models!

    I thought of it first... :p

    --
    johnfoss - Walkin' on the edge

    John Foss, the Uni-Cyclone
    "jfoss" at "unicycling.com"
    www.unicycling.com

    "We choose to go to the Moon in this decade and do the other things, not
    because they are easy, but because they are hard." -- John F. Kennedy,
    1961
    ------------------------------------------------------------------------
    johnfoss's Profile: http://www.unicyclist.com/profile/832
    View this thread: http://www.unicyclist.com/thread/32510
     
  15. Vincelemay

    Vincelemay Guest

    Originally posted by johnfoss
    > I thought of it first...

    Hey John, I know that I'm just teasing all of you again by
    not showing you my suspended muni design, but it's a little
    bit because of what you said above. From last september,
    I've spend countless hours working on a working prototype.
    Now that it's all conceived and the production plans are
    made, I don't want to screw all the work and let a japanese
    cie get all the credit for the first fully suspended
    unicycle. As for patent pending of the machine, I'm on it.
    (don't worry Rayden and pete, it's not the same design as
    yours):p Sorry but I guess you'll have to wait until late
    summer to see it in action.

    --
    vincelemay - Quebec unicyclist
    ------------------------------------------------------------------------
    vincelemay's Profile: http://www.unicyclist.com/profile/5812
    View this thread: http://www.unicyclist.com/thread/32510
     
  16. Cyberbellum

    Cyberbellum Guest

    Wow. You spend time at work for a week and come back to a
    thread and find it's 6 pages long!

    johnfoss wrote:
    > *I don't know if it's different from country to country,
    > but I think patent applications usually (or used to)
    > require a working model of the idea (assuming it's for
    > something you can build a model of).*

    It's a "used to" in the United States. And your protection
    for "thinking of it first" expires one year after publishing
    the idea. I believe posting in this forum counts as
    publishing so if you want to patent you're idea you've got
    less than 365 days to get an application into the proper
    format and submitted. Legal expenses for doing this with an
    original mechanical design generally run from $4,000.00 to
    $9,000.00. Applying for patents in other countries add
    roughly another $10,000.00, but are necessary if you are
    concerned by infringements from foreign manufacturers.

    --
    cyberbellum - Level 1.0 rider!

    Optimists think the glass is half full. Pesimists think the glass is
    half empty. Engineers think the glass is too big.
    ------------------------------------------------------------------------
    cyberbellum's Profile: http://www.unicyclist.com/profile/4550
    View this thread: http://www.unicyclist.com/thread/32510
     
  17. Cyberbellum

    Cyberbellum Guest

    [EngineeringHat]

    The discussion has proceeded far enough that some clear
    design requirements can be stated:

    1) The wheel/suspension system must be rotationally stiff;
    i.e., torque applied to the hub must transfer directly to
    the rim with minimal windup.

    2) The wheel/suspension system must be radially soft; i.e.,
    opposing forces applied at the rim and hub should
    compress the wheel between those two points.

    3) Some level of radial damping is desireable, level to be
    determined through experimentation.

    4) Radial springiness is desireable; again, level TBD
    through experimentation.

    5) The rim must track rigidly in a plane passing through the
    hub at the central point and normal (at right angles) to
    the hub rotational axis.

    6) The wheel/suspension system should be as light as
    possible; weight TBD through design.

    The rest of the requirements concern the standar "-
    illities"; reliablity, maintainability, marketablity,
    and so forth:

    7) The wheel/suspension system should be as durable as
    possible; durability TBD through market resistance.

    8) The wheel/suspension system should be as simple and
    reparable as possible.

    9) etc...

    [/EngineeringHat]

    If I can figure out how to post a powerpoint slide I'll
    submit a design to the discussion.

    Tim

    --
    cyberbellum - Level 1.0 rider!

    Optimists think the glass is half full. Pesimists think the glass is
    half empty. Engineers think the glass is too big.
    ------------------------------------------------------------------------
    cyberbellum's Profile: http://www.unicyclist.com/profile/4550
    View this thread: http://www.unicyclist.com/thread/32510
     
  18. Cyberbellum

    Cyberbellum Guest

    Here are a few of the key ideas:

    1) The sub-rim/spokes/conventional rim structure is light,
    stiff and allows a wheel to be built with any rim/tire
    combination.

    2) The shock/spring mechanisms are as tangential as possible
    so that they resist rotational motions well and radial
    motions poorly.

    3) The pivots and shock/spring mechanisms would be designed
    to resist lateral motions as much as possible to keep the
    wheel rotating in a plane centered on and perpendicular
    to the hub axis.

    Thoughts?

    +-------------------------------------------------------
    ---------+
    | Attachment filename: slide1.jpg |
    |Download attachment:
    http://www.unicyclist.com/attachment/211476| +-------------------------------------------------------
    ---------+

    --
    cyberbellum - Level 1.0 rider!

    Optimists think the glass is half full. Pesimists think the glass is
    half empty. Engineers think the glass is too big.
    ------------------------------------------------------------------------
    cyberbellum's Profile: http://www.unicyclist.com/profile/4550
    View this thread: http://www.unicyclist.com/thread/32510
     
  19. Rayden

    Rayden Guest

    I already had an idea of doing what Cyberbellum did. Good
    idea putting the spokes on the outside of the suspension.
    But I still like my parallelogram design which would
    eliminate windup, while his would only minimize it. Putting
    them at a tanget to the hub is a good idea though, if that
    design were to be used.

    John, I will think about putting the wheel on a seperate
    suspension from the pedals.

    +-------------------------------------------------------
    ---------+
    | Attachment filename: prototype3.jpg |
    |Download attachment:
    http://www.unicyclist.com/attachment/211614| +-------------------------------------------------------
    ---------+

    --
    Rayden
    ------------------------------------------------------------------------
    Rayden's Profile: http://www.unicyclist.com/profile/264
    View this thread: http://www.unicyclist.com/thread/32510
     
  20. Vincelemay

    Vincelemay Guest

    Ooohhhh! That suspension wheel is becoming really great!:cool:

    Those are all nice ideas, but you should also think in 3D
    when you're designing. I do like your parallelogram-
    stifening bars-, maybe it could be like a 4 bars structure
    to avoid side-to-side twisting (brake rubbing). My 2 cents.
    Keep on the good engeneering!

    Vincent

    --
    vincelemay - Quebec unicyclist
    ------------------------------------------------------------------------
    vincelemay's Profile: http://www.unicyclist.com/profile/5812
    View this thread: http://www.unicyclist.com/thread/32510
     
Loading...
Loading...