Friday, August 28, 2009

pic of proposed system for one-size-fits-all bent belt

D: this system would allow small to large riders to all use one standard size of belt.
For my purposes, it may allow me to adapt the bike to a pre-existing length of industrial toothed belt rated at least 1000 kgf.
Though this requires great care in gearing to avoid too much torque.
It probably favours a fast cadence of 100rpm or higher.

I don't think a front 26" wheel will play well with this.
I was already thinking 24" a the front.
I am unwilling to go down to 20" since the road bumps are felt severely.
Of course a 24"26" wheel layout pretty much requires alloy rims to keep the weighty feel of the spinning centrifugal momentum down.
I am not worried much about the gear and dynamo hubs since they are not at the rim.

I see that the adjustable point under the seat is also an ideal place to mount a motor assist. I was still pondering that Tetz 12V system.
I'd very much like mount a dynamo there instead of on the front wheel.

This layout precludes a chain-thru-frame layout, though, a la Green Machine.

As much as I'd dearly love a proper generator as opposed to just a dynamo, the weight penalty and complexity seem to preclude it.
The FreeCharge 12V Personal Energy Source is a lightweight, durable and efficient power source for mobile phones and other electronic devices. The self-charge system is powered entirely by winding a hand crank, so is independent of all conventional power supplies or batteries, enabling you to make and receive calls, or charge other personal electronic devices, at any time.

The FreeCharge 12V consists of a generic base unit and interfaces to the coupled device through a generic cigarette lighter socket.

My design goal was around 100 input watts to the motor and less than 10 pounds total system weight. It came in at 4.2 pounds, 1.9kg ! -- That’s every thing – motor/gearbox/freewheel/mounting bracket assembly, battery, electronic controls.


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