Chain Driven Dynamo

On 11/4/2015 2:56 PM, Frank Krygowski wrote:
On 11/4/2015 12:43 PM, sms wrote:
Forget tire driven dynamos that wear out the sidewall of
the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html


Love the Chinglish. That's always a sign of a top quality
product, right? ;-)

I guess we're now going to be treated to SMS "guerrilla
marketing" for all AliExpress bike items.

What's your cut on these, Steve?

For those unfamiliar with "guerrilla marketing," Scharf says
on one of his sites "I receive a small percentage of sales
when you use these links." And on another page: "We
believe in guerilla marketing. We engage with the all
segments of the bicycling community in the promotion of our
products."

So, I guess we're engaged!


Yeah, I don't click those either. Search shows it at Amazon.

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

On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html

Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 11/4/2015 5:20 PM, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html

Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


A roller? That's a great idea. Maybe it could run against
the tire? Wonder why no one ever thought of that.

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

On 2015-11-04 15:35, AMuzi wrote:
On 11/4/2015 5:20 PM, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html


Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


A roller? That's a great idea. Maybe it could run against the tire?
Wonder why no one ever thought of that.


Do you know why roller dynamos fell from grace? In the 80's they were
all the rage with serious longhaul cyclists and then some time in the
90's ... poof ... gone.

--
Regards, Joerg

http://www.analogconsultants.com/

On Wed, 04 Nov 2015 15:44:54 -0800, Joerg
wrote:

Do you know why roller dynamos fell from grace? In the 80's they were
all the rage with serious longhaul cyclists and then some time in the
90's ... poof ... gone.

Cheap white LED's hit the market in about 1997, which made battery
powered bicycle lighting practical.
http://www.osram.com/osram_com/news-and-knowledge/led-home/professional-knowledge/led-basics/led-history/index.jsp
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 11/4/2015 3:44 PM, Joerg wrote:

Do you know why roller dynamos fell from grace? In the 80's they were
all the rage with serious longhaul cyclists and then some time in the
90's ... poof ... gone.

My touring bicycle even had internal wiring for a bottom bracket roller
dynamo. The Sanyo roller dynamo made a brief reappearance a couple of
years ago, then disappeared again
http://www.peterwhitecycles.com/images/products/Lights/sant110bb.jpg.

There's a crude looking one available again, see
http://www.amazon.com/dp/B00Q8770WU.

On 05/11/15 09:20, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html

Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


Any bicycle with a rear derailleur already has a pair of sprockets with
the chain wrapped around. Could at least be used to keep the battery
charged that runs electronic gear shift mechanisms these days.

--
JS

James wrote:
On 05/11/15 09:20, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html

Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


Any bicycle with a rear derailleur already has a pair of sprockets with
the chain wrapped around. Could at least be used to keep the battery
charged that runs electronic gear shift mechanisms these days.


That makes some sense. After all, if you're not pedalling, you probably
have no need to shift, so the odds of matching power delivery and power
requirements looks good.

On Thu, 05 Nov 2015 05:46:39 GMT, Ralph Barone
wrote:

James wrote:
On 05/11/15 09:20, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html

Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


Any bicycle with a rear derailleur already has a pair of sprockets with
the chain wrapped around. Could at least be used to keep the battery
charged that runs electronic gear shift mechanisms these days.


That makes some sense. After all, if you're not pedalling, you probably
have no need to shift, so the odds of matching power delivery and power
requirements looks good.

You missed the part about "used to keep the battery charged"?

--
cheers,

John B.

On Thursday, November 5, 2015 at 12:44:51 AM UTC+1, Joerg wrote:
On 2015-11-04 15:35, AMuzi wrote:
On 11/4/2015 5:20 PM, Jeff Liebermann wrote:
On Wed, 4 Nov 2015 09:43:59 -0800, sms
wrote:

Forget tire driven dynamos that wear out the sidewall of the tire, or
expensive hub dynamos that require a new wheel.

http://www.aliexpress.com/item/Action-Bicycle-Dynamo-Chain-Dynamo-BICYCLE-GENERATOR-5V-Output-for-Mobile-Phone-MP3-Music-Angel-Flashlight/531798718.html


Ummm... I wonder how long the plastic thingy that keeps the chain from
popping out of the dynamo sprocket will last? A problem with all
chain and sprocket arrangements is that they only work well if the
chain is partly wrapped around the sprocket. Any other arrangement,
such as this linear configuration, results in the chain trying to lift
itself away from the sprocket. Only the plastic thingy keeps the
chain from skipping teeth or just skimming the tops of the gear teeth.
Since the sprocket teeth are cut at about a 45 degree angle, about
half of the chain drive force is directed perpendicular to the
sprocket center, which then tries to pull the chain away from the
sprocket.

The good news is that the dynamo doesn't produce much power (maybe 10
watts for USB?), and therefore offers little resistance. It's half
this force that produces the power, while the other half tries to pull
the chain away from the sprocket, grind the chain into the plastic
thingy, and produce some additional drag.

Instead of a plastic friction pad thiny, maybe a roller or two
instead?


A roller? That's a great idea. Maybe it could run against the tire?
Wonder why no one ever thought of that.


Do you know why roller dynamos fell from grace? In the 80's they were
all the rage with serious longhaul cyclists and then some time in the
90's ... poof ... gone.

--
Regards, Joerg

http://www.analogconsultants.com/

That was because hub dyno's became available for a fair price, a much better solution. Here we were glad we got rid of the bottle dyno's which today only are used in cheap 'Walmart' bikes.

Lou