Pneumatics would do fine, and I was thinking of a water brake or sorts
to keep the rate controlled.
Vacuum might be easier to work with. This way the only time you need
the actual vacuum would be to lower the platform, then let a counterweight
raise it. It won't pass OSHA, but its simple. By controlling the rate that
the vacuum re enters the cylinder (controlled flow check restructure sort of
thing) you can let the cylinder do the braking. Not at all dissimilar is a
vacuum elevator. Google for "vacuum elevator"

"Jake" wrote in message
ups.com...
| I have a 100 pound platform that shall rest at a height of 6 feet. The
| user will pull it down to about 3 feet and climb aboard. When the user
| gets off, the platform should slowly raise to its original height of 6
| feet. I plan to accomplish this using a pneumatic cylinder or two,
| where one side is the platform and the other is a counterweight of
| about the same weight as the platform. Will pneumatics be good for
| this or perhaps a pulley system would be better? It shouldn't be too
| hard to pull the platform down for a 150 pound person, and the platform
| should not shoot up, potentially doing damage to the project, or anyone
| nearby.
|
| Ideas?
|
| Jake
|