I've been working on a project that, if I manage to build it as designed, would require four actuators or some kind no more than 1" in diameter. Hydraulics seem to be a good fit for this application (I wouldn't need more than 30 PSI, single acting only) since compressed air would be too "spongy." The actuators also need a total travel of about 24."
That's where I run into trouble: I can't find hydraulic cylinders that meet the bore and stroke requirements. I have an idea to build my own which I'd like some feedback on before I dive in, or perhaps someone has an alternate suggestion.
I have some thin walled, 1" chromed shower rod that makes a perfect outer cylinder (and the chrome finish would look snazzy!). Add in some 1/2" PVC pipe for the inside and I think I'm pretty close.
First attempt was to make molded silicone pistons on the PVC. I got some pretty good results but it's not entirely leak-proof, so I lose pressure.
My next idea is to use a rolling-sock seal made of 1" lay-flat PVC discharge hose. Bind the hose to the PVC pipe with a good seal, double it up over the pipe and seal the other end before stuffing it into the metal tube.
Anyone think this is a lost cause, or have another suggestion?