How do cranes lift heavy loads?

I work for a crane manufacturer, so I know something about it. A crane like QDY Hook Bridge Casting Crane is a mechanism that uses a collection of simple machines to both raise and lower objects, and also move them horizontally. They are always equipped with at least a winder; cables, ropes，chains or sheaves. 

So how does the crane work? The main work is divided into four items, namely lifting, running, bluffing, and rotating.
"Lifting" means lifting heavy objects, which can meet the requirements of heavy objects for vertical lifting. As the most basic item in crane work, it is the soul of the entire lifting work;
If the object needs to be moved horizontally, the second job is used, that is, "running";
"Luffing" is to lift long-distance objects by changing the length and angle of the crane jib; after the lifting is completed, if you want to transport heavy objects back long-distance,
That's where the fourth job comes in, the "swivel," where the swivel jib travels around the crane for transfer.

These four tasks constitute the complete operating system of the crane. In the daily work of the crane, whether it is a single work item or a combined work item, it can accurately move the item to the designated position.