Hello! I am a 1st time poster here who needs some fresh ideas. After lurking around several forum, I think this is the place to get them. Objective: Propel a cart carrying a 1400 pound part using energy collected from action of loading the part onto the cart. Current idea: I am picturing a plunger that is depressed by the part. The plunger spins the mechanism that winds the spring. I fear how large the spring would need to be though. What kind of mechanism would you recommend?