Thread: Anyone know about pneumatics?

These guys do.
Festo > Pneumatic & Electric Automation Worldwide | Cylinder, Actuator, Drive, Valve, Sensor and Compressed Air Supply

most camper railers use gas struts.........

using pueumatics rams would require a compressor and a sizable receiver i would have thought

I've done a significant amount with pneumatics.

First you need to work out the geometry, because that dictates the force you require from any cylinders. Then it's as simple as F = pressure*area. Your supply pressure is normally fixed (work to minimum pressure available, not max pressure) and you pick a cylinder size to get the piston area you require.

But bigger bore cylinders are longer for the same stroke, so this can be an iterative process as the geometry can change to fit a longer cylinder in.

Once you have the cylinder sorted, for smooth control you want a 5 port valve. These 5 ports are supply, pressure to each cylinder port (air cylinders are almost all double acting, both lines need connected to keep dust out) and exhaust for each cylinder port.
You can fit flow-controls to the cylinder ports to slow down and control the operation. These work by controlling the flow out of the cylinder and are adjustable. Flow in is unimpeded.

if you fit gas springs everthing becomes a compromise.

• lot of the install ive done require gravity and as you lift, if the strut works from the start then you have to lock it down in compression. then you have to have dampening as it revolves around the arch.then the strut must be strong enough to handle the load at odd angles.
• I have used electric linea actuators.,pneumatic by them self may turn the project into a catapult. the pistons we use on road repair bitumen truck when they get stuck the pressure builds up till something gives.these use 120 psi.

Ive had to construct systems that uses multiple struts at different angles. items like double acting doors,all becomes a bit hard after the item was built

Pneumatics, as per the previous, tend to move in spurts, pressure builds up overcomes the stiction and takes off. Then the process repeats. I have raised pneumatic masts and they bounce their way up. Hydraulics are much smoother and predictable.

Have you considered winch and pulleys or geared tracks, you can use a cordless drill to drive the whole thing if you don't like cranking the handle.

Originally Posted by slug_burner

Pneumatics, as per the previous, tend to move in spurts, pressure builds up overcomes the stiction and takes off. Then the process repeats. I have raised pneumatic masts and they bounce their way up. Hydraulics are much smoother and predictable.

Pneumatics will never be as rigidly controllable as hydraulics. But with simple exhaust flow controls you can tune that stick-slip down until it's imperceptible.

Linear actuators are another option. Simple to set up, slow and controllable