man with drill
A hydraulic manifold is a device used to direct the flow and pressure of hydraulic fluid to different areas of the hydraulic system. Usually made of steel or aluminum, the hydraulic manifold is equipped with actuators that are manually operated via levers or switches or manipulated by electronic actuators that may be actuated by a computer or switch somewhere on the machine. Actuators on a hydraulic manifold act to control or modulate hydraulic valves that open and close to create the desired flow path of hydraulic fluid.
Some hydraulic systems, such as those used on a backhoe tractor, are hydraulic cylinder systems that work with pressurized hydraulic fluid. The fluid is pressurized by a hydraulic pump that feeds it through a series of hydraulic lines. The hydraulic manifold directs fluid to individual hydraulic cylinders by closing valves in one area of the manifold and opening others. This movement of hydraulic fluid is controlled by an operator pulling and pushing control levers attached to the hydraulic manifold. Each valve in the hydraulic manifold operates in a push-pull motion, and hydraulic fluid is pressurized and released by manipulating a control lever.
In any hydraulic system, there may be more than one hydraulic manifold. In the case of a typical backhoe tractor, there are typically two spool valves: one that controls the front-mounted bucket and the other that controls the rear-mounted backhoe attachment. The front manifold is usually made up of either a two-lever manifold or a single joystick-type controller. In either case, the truck is typically equipped with four actions: bucket raise, bucket lower, bucket roll back, and bucket roll forward. Moving a control in one direction completes one operation, such as raising the bucket, and moving the control in the other direction completes the opposite reaction, such as lowering the bucket.
Each manifold valve is made up of a cylinder, a spring, and a rubber diaphragm. As the valve is manipulated by the control lever, the cylinder is directed to one fluid path or another, each directing a particular action. The spring located inside the valve holds the valve in a neutral position and prevents fluid from entering or exiting the valve and manifold. Often there is an adjustment on the hydraulic manifold that increases or decreases the amount of hydraulic pressure going into the manifold, speeding up or slowing down the reaction to moving a control lever.