Jump Start Bicycle Freewheel Cog: Simple & Robust Designs

[thorpie]

Hello
I need a method of locking a freewheel cog at the back wheel of a bicycle.
Have motorized bicycle. It has a chain from the engine to an overrun cog on back wheel. The engine will only be used intermittently, about 10% of the time. I need to jump start the engine often, but I need as little effect on the pedaller as possible whilst the engine is not running. Hence the overrun cog at the back wheel rather than a constantly driven chain with a clutch up at the engine.
Would anyone know of any simple robust designs, preferably off the shelf.

 

[Navin A S]

One possible solution is to use a ratchet-style freewheel cog. This type of cog has teeth that fit together like a puzzle, and the wheel will turn backward but not forward. This would keep the wheel from rotating while the engine is off, but still allow it to rotate when the engine is running. You could also use a one-way bearing, which is a small device that is designed to lock the wheel in place but still allow it to rotate in one direction. This would also prevent the wheel from turning while the engine is off. Both of these options should be relatively easy to find and install.