[archiver]

Posted by Shawn McMahon at 2/4/2001 12:46 PM EST


Student on team #263, Aftershock, from Sachem H.S. and Symbol, Citycorp., Apoge, CA ....


In Reply to: Pushing on both sides of the piston...
Posted by Joe Johnson on 2/3/2001 5:24 PM EST:



You are right. The piston does act like a spring, but a very strong one (In our case). What size piston were you testing the system with? On smaller pistons it would act more like a spring, being easier to push because of less surface area inside the piston. The optimal system would have the shortest hoses. Normaly longer hoses would be better, acting as a resevoir. In this case using smaller hoses would leave less air to be compressed giving you a stronger spring.

When we tested it we had someone try to push or pull the spring. The most they could move it was about an inch. (with the check valve in the system to prevent leakage.) That was good enought for us. We don't need to "lock" the piston in place. We just needed to stop the piston partly through its motion so we could position our arm to allow us to move under the barrier.

It would be physicaly impossible to completely lock the piston. To create a stronger spring you could use both spring loaded valves conected directly to the piston (using the shortest tubes possible). The only compressable air would be the air within the piston.

This would also allow you to use the check valve somewhere else. In our case we want to use it as a quick refill port. This gives us the ability to charge the tanks before the match with an outside compressor, eliminating the need to turn on the robot before a match.