Underwear cleaner

[flyingsquirrel25]

Riggs the difference between a dump and a aerial lift is the lock valve on a lift is at the cylinder so that there is no hose to fail between the lock valve and the cylinder. I have never seen a dump with a lock valve on it just the normal 2 way up, down valve. Im sure someone has seen it, I just havent. Thats why they put those safety props under the body. If the hose springs a leak it comes down. Niether my tractor or my dump have lock valves.

 

[allmark]

The valve will not prevent allcylinder failures. If the cylinder fails within the fluid can circulate past the seals and wiper in the cylinder without going to the valve. It will often seep allowing the cylinder to move slowly but also can be more drastic. I have had cylinders on cranes which would creep with a good holding valve. I have also had a valve get a piece of dirt which allowed a boom to fail. Most holding valves require pressur to openm them allowing fluid into the cylinder by pushing the valve(with a spring) open. This is the same concept as air brakes. No air and the brake is applied. When the air pressure is applied the brake releases. But if something breaks beyond that it doesnt help.