Hey, I'm trying to design a part for a prosthetic leg. I need to stop a piston moving within a cylinder at any point in its motion. (this will happen when the patient puts weight on his foot) I was thinking about having the piston turn a gear, and then when it's time to stop it, another gear-like piece will jam into the gear, stopping the system. The gear won't be spinning fast, but will have a pretty strong force. Does anyone have any thoughts on how this might be done? Thanks.