what was the bicycle with the variable-tooth sprocket?

On 7/22/2012 5:34 AM, Doug Cimperman wrote:
On 7/21/2012 10:41 PM, DirtRoadie wrote:
On Jul 21, 5:56 pm, Doug Cimperman wrote:
All over the maker blog sites today is this guy who has designed a
variable-tooth sprocket for
bicycles:http://www.blendernation.com/2012/07...variable-tooth...


Somebody already did this some years back though, I remember seeing the
video showing a working example (the actual bike with this setup). You
held a hand-control lever and then pedaled forward or backward to change
the effective sprocket size. Does anybody else remember what I'm talking
about?

I don't know if it was ever an actual product offered for sale, it may
have only gotten to the prototype stage.

This is one of those holy grail concepts that MANY have attempted.
I do remember a commercial version that used a group of small
planetary cogs positioned to create a more-or-less circular array (an
effective chainring), with each small each cogs movable to allow the
radius of the array to be varied. I can't recall the name and don't
know whether it was patented. It may have been related to an
"automatic" shifting device.
This is similar in concept with the group of small cogs:
http://www.google.com/patents/US3969...intsec=drawing

But with regard to the cited concept, here's a patent from '01 -
probably not the century you were expecting though
http://www.google.com/patents/US672962?printsec=drawing

DR

test test??

god dammit. charter ****ing sucks, keeps losing the actual messages.......

On 7/22/2012 5:35 AM, Doug Cimperman wrote:
On 7/22/2012 5:34 AM, Doug Cimperman wrote:
On 7/21/2012 10:41 PM, DirtRoadie wrote:
On Jul 21, 5:56 pm, Doug Cimperman wrote:
All over the maker blog sites today is this guy who has designed a
variable-tooth sprocket for
bicycles:http://www.blendernation.com/2012/07...variable-tooth...



Somebody already did this some years back though, I remember seeing the
video showing a working example (the actual bike with this setup). You
held a hand-control lever and then pedaled forward or backward to
change
the effective sprocket size. Does anybody else remember what I'm
talking
about?

I don't know if it was ever an actual product offered for sale, it may
have only gotten to the prototype stage.

This is one of those holy grail concepts that MANY have attempted.
I do remember a commercial version that used a group of small
planetary cogs positioned to create a more-or-less circular array (an
effective chainring), with each small each cogs movable to allow the
radius of the array to be varied. I can't recall the name and don't
know whether it was patented. It may have been related to an
"automatic" shifting device.
This is similar in concept with the group of small cogs:
http://www.google.com/patents/US3969...intsec=drawing

But with regard to the cited concept, here's a patent from '01 -
probably not the century you were expecting though
http://www.google.com/patents/US672962?printsec=drawing

DR

test test??

god dammit. charter ****ing sucks, keeps losing the actual messages.......


this one from 1980 operates and looks exactly like what I recall-
http://www.patentgenius.com/patent/4493678.html

i might have seen it on TV I guess. or maybe the guy was still plugging
away into the 1990's

On 7/21/2012 6:56 PM, Doug Cimperman wrote:
All over the maker blog sites today is this guy who has
designed a variable-tooth sprocket for bicycles:
http://www.blendernation.com/2012/07...bike-sprocket/


Somebody already did this some years back though, I remember
seeing the video showing a working example (the actual bike
with this setup). You held a hand-control lever and then
pedaled forward or backward to change the effective sprocket
size. Does anybody else remember what I'm talking about?

I don't know if it was ever an actual product offered for
sale, it may have only gotten to the prototype stage.

Among others there was the Tokheim Variable system

Patent:
http://www.freepatentsonline.com/3861227.html

This 1985 patent references prior art to 1903:
http://www.freepatentsonline.com/4493678.html

video !
http://www.youtube.com/watch?v=EoMJl...ature=youtu.be

Which shows a rear change system. The one I recall was a
variable front of similar design.


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

Per Doug Cimperman:
this one from 1980 operates and looks exactly like what I recall-
http://www.patentgenius.com/patent/4493678.html

i might have seen it on TV I guess. or maybe the guy was still plugging
away into the 1990's

Sounds like NuVinci is still alive and kicking:
http://www.parktool.com/blog/calvins...Vinci-360-Hub+
--
Pete Cresswell

In 1996, I test-rode a bike with a prototype of the
mechanism described in US patent 5,516,132 and shown at
http://minortriad.com/cvt.html

The number of teeth effectively varies.
It's impractical for several reasons
but it did work when I rode it.

Tom Ace

On Jul 22, 12:56*am, Doug Cimperman wrote:
All over the maker blog sites today is this guy who has designed a
variable-tooth sprocket for bicycles:http://www.blendernation.com/2012/07...variable-tooth...

Somebody already did this some years back though, I remember seeing the
video showing a working example (the actual bike with this setup). You
held a hand-control lever and then pedaled forward or backward to change
the effective sprocket size. Does anybody else remember what I'm talking
about?

I don't know if it was ever an actual product offered for sale, it may
have only gotten to the prototype stage.


A variable tooth chainring was produced under the name Deal-drive by
Michael(?) Deal. Developed about 1980/1 , possibly marketed in 1984,
I don't know if there were any sales.

On 07-22-2012 11:43, (PeteCresswell) wrote:
Per Doug Cimperman:
this one from 1980 operates and looks exactly like what I recall-
http://www.patentgenius.com/patent/4493678.html

i might have seen it on TV I guess. or maybe the guy was still plugging
away into the 1990's

Sounds like NuVinci is still alive and kicking:
http://www.parktool.com/blog/calvins...Vinci-360-Hub+

http://nuvinci.informe.com/forum/


--
Wes Groleau

If you put garbage in a computer nothing comes out but garbage.
But this garbage, having passed through a very expensive machine,
is somehow ennobled and none dare criticize it.

Per Wes Groleau:
Sounds like NuVinci is still alive and kicking:
http://www.parktool.com/blog/calvins...Vinci-360-Hub+

http://nuvinci.informe.com/forum/

Seems like NuVincis can be had for under $400... although I can't
figure out if they take disc brakes.

OTOH, I just looked at a Rohloff price: Twelve-Hundred Bucks !!!!

I think I paid something around 800 for mine.... Talk about
inflation...

--
Pete Cresswell

On 7/22/2012 6:54 PM, (PeteCresswell) wrote:
Per Wes Groleau:
Sounds like NuVinci is still alive and kicking:
http://www.parktool.com/blog/calvins...Vinci-360-Hub+

http://nuvinci.informe.com/forum/

Seems like NuVincis can be had for under $400... although I can't
figure out if they take disc brakes.

OTOH, I just looked at a Rohloff price: Twelve-Hundred Bucks !!!!

I think I paid something around 800 for mine.... Talk about
inflation...


Staton (a online retailer selling kits and parts for motorized bicycles)
used to list a gas-engine kit based on the NuVinci. This had a 2 HP
engine driving a ~40T sprocket on the cog-side of the hub itself--so the
engine power was being transmitted through the CVT-drive of the hub.

Which was pretty surprising, because NONE of the other IGH's are
anywhere near strong enough for that. People have attached engines onto
the Nexus and Sturmey-Archer hubs and had them fail within days of only
moderate use. They must be used as an intermediate drive, so that they
aren't ever under much torque.

,,,,

Non-engine bicycle enthusiasts dislike the NuVinci because apparently it
has more internal drag than any other hub.

On 07-22-2012 19:54, (PeteCresswell) wrote:
Seems like NuVincis can be had for under $400... although I can't
figure out if they take disc brakes.

Conversion kit has MSRP of $400 US

Available with disk brake, rim brake, or ... pull brake? Something I'd
never heard of, unless it's what I called a "coaster brake" when I was a
kid.

--
Wes Groleau

“Ideas are more powerful than guns,
We would not let our enemies have guns;
why should we let them have ideas?�
— Jozef Stalin