The hand-crank stacker - also known as a manual hydraulic stacker - consists of three main components: a hydraulic system, a mast, and forks.
This vehicle utilizes a manual hydraulic jack (i.e., the hydraulic unit) as the power source to lift heavy loads, while human effort is used to push or pull the vehicle for transport. The hydraulic unit is equipped with a return valve; this valve allows the operator to control the lowering speed of the forks via a handle, ensuring that the hydraulic system operates correctly, safely, and reliably. The mast is constructed from high-quality structural steel, welded together to provide excellent rigidity and high structural strength. The rear wheels are swivel casters fitted with braking mechanisms, allowing for free rotation and agile, flexible maneuvering. Both the front and rear wheels are mounted on their axles using ball bearings, ensuring smooth and effortless rotation. The wheels themselves are made of nylon, offering excellent wear resistance and durability while minimizing the risk of damage to the working floor surface.
When lifting cargo, the forks are inserted beneath the cargo pallet; if necessary, the rear-wheel brakes can be engaged. The operator then actuates the handle. This action causes a pressure roller to compress the pump core, forcing the hydraulic fluid from the pump cylinder into the piston cylinder. This drives the piston rod upward, which, through a chain mechanism, lifts the forks to a height equal to twice the piston's stroke. By repeatedly actuating the handle, the cargo is progressively lifted until the desired height is reached. When the forks reach their maximum lifting height, the pressurized hydraulic fluid flows back into the reservoir through a relief port; at this point, even if the handle is actuated further, the forks will no longer rise, thereby preventing mechanical damage caused by "topping out" (over-extension).
When transporting heavy loads, the stacker can be moved by manually pushing or pulling the vehicle.
To unload cargo, the operator actuates the release handle. This opens the return valve, allowing the hydraulic fluid within the piston cylinder - driven by the combined weight of the cargo and the forks - to flow back into the reservoir through the return valve. Once the piston rod and forks have descended to their lowest position, the cargo can be unloaded and the forks withdrawn.
