Recent content by pretend engine

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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    But the piston is part of a vehicle engine.. how would we stop the crank?
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    Thanks for all the info. The taper discussion was very helpful and interesting. I want to see if I'm understanding your ideas correctly, so here's another quick sketch. Hopefully it's decipherable. The top is the same collet sketch. bottom left: rack and rack, bottom right: split nut...
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    Thanks, Baluncore. I need to digest all the information you've given me here. I really appreciate your interest. We are a group of senior mechanical engineering students, and this is our first real engineering project. We are designing a knee with specific attributes to conform to the athletic...
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    OK, thanks. F is the force being applied and V is the velocity vector of the rod. By reactive materials, what do you mean? Do you think the collet will unclamp easily, to allow the shaft to move freely again, or would you spring load it? Again, thanks for the help. This seems like it...
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    Does this sketch look like what you're picturing? http://imagizer.imageshack.us/v2/150x100q90/9/vn49.jpg
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    Great idea! I think so at least, it's hard for me to picture. So friction stops the rod? Do you think that can hold up a persons weight? Can you recommend an example that I can search for? The only context I can find is drill chucks.
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    Thanks to you both. I like the hydraulic cut off idea. Is it possible to do that in a way where the fluid will not be restricting the movement of the piston when the valve is open? (not slowing the piston down while forcing fluid out of or sucking fluid into the cylinder) Baluncore, I'm having...
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    How to suddenly stop a gear? (or how to suddenly stop a moving piston)

    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...
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