Hydraulic machines use fluid to transmit force.

Photo courtesy Caterpillar

­From backyard log splitters to the huge machines you see on construction sites, hydraulic equipment is amazing in its strength ­and agility! On any construction site you see hydraulically operated machinery in the form of bulldozers, backhoes, shovels, loaders, fork lifts and cranes.

Hydraulics operate the control surfaces on any large airplane. You see hydraulics at car service centers lifting the cars so that mechanics can work underneath them, and many elevators are hydraulically operated using the same technique. Even the brakes in your car use hydraulics!

In this ar­ticle, you will learn about the basic principles that hydraulic systems use to do their work, and then we'll examine several different pieces of hydraulic machinery found on a construction site. You will be amazed at the power and versatility available with hydraulics.

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