We all know how a typical friction drive works... What if by using a simple air piston- activated by pulling a small convenient lever, the typical friction drive could be transformed into a dual- roller drive, high and low gear system... Perhaps this is a solution to the idea...
Below I have several pictures illustrating how this system could work.
Use a C02 container (like one's found on a paintball gun). Attached to the C02 container is a regulator which decreases the PSI down to aprox. 100psi. Next, the constant 100psi pressure is fed into a 3-way valve, splitting the pressure into an 'A' or 'B' line. These lines each are attached to a simple 1-way exhaust valve (to prevent back pressure). Finnally, these lines feed into a small air piston called a Pancake piston, which is attached to the frame of the bike and the frame of the friction drive unit.
When the valve is opened to line 'A', the piston opens up to either 1, 2, or 4 inches (whichever fits the application best), and the back roller contacts the tire. When valve 'A' is closed, and valve 'B' opens, the piston retracts, contacting the front roller with the tire.
There are only two potential problems I see with this set-up:
The chain that would be used to turn both rollers would have to spin at a high RPM. I feel the best chain to do this would be a timing chain, since they are designed for hard usage.
The addition of a chain and second drive roller would add a small amount of resistance to the motor.
Ultimately, I don't know if this system would work. I was thinking it was plausible though. I have never built any kind of motorized bike, but am very intregued by the thought. And since I am a larger guy, I thought this system might provide both a high torque and higher speed options. Please leave some comments guys, and sorry about the vagueness of the pictures, I hope they are self-explanatory.
Below I have several pictures illustrating how this system could work.
Use a C02 container (like one's found on a paintball gun). Attached to the C02 container is a regulator which decreases the PSI down to aprox. 100psi. Next, the constant 100psi pressure is fed into a 3-way valve, splitting the pressure into an 'A' or 'B' line. These lines each are attached to a simple 1-way exhaust valve (to prevent back pressure). Finnally, these lines feed into a small air piston called a Pancake piston, which is attached to the frame of the bike and the frame of the friction drive unit.
When the valve is opened to line 'A', the piston opens up to either 1, 2, or 4 inches (whichever fits the application best), and the back roller contacts the tire. When valve 'A' is closed, and valve 'B' opens, the piston retracts, contacting the front roller with the tire.
There are only two potential problems I see with this set-up:
The chain that would be used to turn both rollers would have to spin at a high RPM. I feel the best chain to do this would be a timing chain, since they are designed for hard usage.
The addition of a chain and second drive roller would add a small amount of resistance to the motor.
Ultimately, I don't know if this system would work. I was thinking it was plausible though. I have never built any kind of motorized bike, but am very intregued by the thought. And since I am a larger guy, I thought this system might provide both a high torque and higher speed options. Please leave some comments guys, and sorry about the vagueness of the pictures, I hope they are self-explanatory.