Forklift cylinders, or hydraulic cylinders, as they are also commonly called, control the movement of the lift on a forklift. The up and down motion as well as the back and forth leaning action of the fork assembly are all controlled by the forklift cylinders mounted within the framework of the lift mechanism. Some forklifts are equipped with a shift function that uses forklift cylinders to slide the forks from side to side to allow an operator to stack pallets and other objects very closely together. Specialized forklifts, such as a lift fitted with a squeeze option, use hydraulic cylinders to close the clam-style grips tightly together.
Regardless of the style of forklift, whether it is battery-powered or gas-powered, the forklift cylinders are commonly operated via an electric hydraulic pump. The forklift cylinders are operated through a set of control levers mounted in the operator's compartment of the forklift. Light-duty forklifts typically use a single cylinder to raise the fork assembly, while heavy-duty lifts commonly use a pair of forklift cylinders to raise the lifting forks into the air. The benefit in using dual cylinders is that if one cylinder should happen to break a hydraulic hose or become damaged in any way, the second cylinder will prevent the forks and load from plummeting to the floor.
One of the most difficult tasks to manage when learning to operate a forklift is maneuvering with the steer tires on the rear of the lift. The second most difficult factor for many people is to learn the control lever functions. Once memorized, the forklift cylinders can be manipulated and operated with precision and speed, requiring only the feel of the levers to do so. Often, when looking at a storage area high above the forklift, there is no time to look down at the control levers. The levers must typically be manipulated by feel as the operator needs to watch the placement of the load.
As part of a pre-operation check, the hydraulic hoses should be examined for leaks, tears and wear marks. Any damage to the hoses or the forklift cylinders should be recorded and brought to the attention of the service department personnel. During any inspection, the forklift cylinders should be run fully out to allow inspection of the inner shaft. Any rust, pitting or discoloration should also be reported to the service department. If the hydraulic cylinders become sluggish or slow, it could be related to a low hydraulic fluid level, a weak hydraulic pump or a problem in the metering blocks attached to the control levers.