There are two mechanisms that enable forklifts to perform their lifting functions: roller chain pulleys and hydraulic cylinders.
1. Hydraulic cylinders
Found at the base of a forklift is the lift handle which is fixed to an electric-powered air pump. When an operator presses the handle, the air pump is turned on. It then draws the air outside into the filter and pushes it into a tube until it reaches the hydraulic cylinders. The hydraulic cylinder has a hollow tube closed with a flexible, lubricated piston at one end.
The base of the cylinder traps air without leaking it out. As pressure increases in the area of the piston, an upward force is generated, moving the piston up. As this happens, the volume of gas increases, and the pressure is minimized. This produces physical equilibrium at the height of the forklift and an amount of force that’s equivalent to the gas and the load of the forklift.
To elevate the load – The forklift operator pushes the handle (forward direction) to signal the forklift to pump excess air into the cylinders.
To lower the load – In a backward direction, the operator pulls the handle to signal a special valve to release gas from the cylinders.
2. Roller chain pulley
The forks that lift and carry loads are fixed to the main body with two roller chain pulleys. The fulcrum of these chain pulleys forms a gear above the mast. As the hydraulic pistons push the mast upwards, the gears at the top of the masts are pressed on the roller chains. This takes place because one side of the chain is attached to the forklift’s solid frame. The masts can only move in an upward direction when the gears rotate clockwise, pulling the forks overhead.
This mechanism is vital, as it allows the forks to move away from the cylinders’ reach. The forklift would need taller cylinders to lift loads to an equal height if not for roller chain pulleys.
Forklift trucks have revolutionized the storage and shipping of goods in various workplaces. Since they were invented in the dawn of the 20th century, forklifts have become the integral machine in industrial workplaces, including: