Maximum bore/stroke length for cylinders?

[hrench]

Originally Posted by GeeTwo

you could actuate the "return" stroke pneumatically using much less air (probably 75-80% less) than the power stroke.

I expect you could accomplish the same thing by putting a regulator set to a lower pressure in the line between the solenoid valve and the cylinder extension (we lift with the 'return'). Legal? Don't know.

Originally Posted by GeeTwo

The time for the power stroke is the biggest problem. You'd probably be better off with two 18" stroke cylinders mounted to each other, pointing in opposite directions and pressurizing them through different solenoid valves. The returns could be through one solenoid valve.
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i don't understand why you think two cylinders would be better than one? The lift area (piston in2) will still be determined by the weight of the robot and the total volume will just be the lift area times the lift distance.

Unless you mean you extend with a small diameter cylinder while the 2" is open to free atm, then open the little one to atm and lift with the big one.

And all of those people that are worried that the valves and the fittings won't be big enough to be fast --pretty unlikely that they'll even be a factor. You'll run out of air and have to wait for the compressor.

[GeeTwo]

Originally Posted by hrench

i don't understand why you think two cylinders would be better than one? The lift area (piston in2) will still be determined by the weight of the robot and the total volume will just be the lift area times the lift distance.

Yes, the force will be the same.

Originally Posted by GeeTwo

The time for the power stroke is the biggest problem.

I'm concerned that they might not be able to get enough air through one of those tiny 1/8" solenoid fittings. Since you cannot legally plumb the output of two solenoid valves together, you need two cylinders to each do half the work.

Actually, thinking it through a bit farther, two 1.5" cylinders with a 36 inch stroke would be even better. You could locate these to the sides of the robot and it would stabilize the rotation of the lift as well.