Did you know that container spreaders can generally be divided into several categories?

Container spreaders can generally be divided into two major categories: fixed, non-telescoping spreaders and telescoping spreaders. Fixed spreaders can be further classified into independent spreaders and master-slave spreaders.

Based on the method of connection to the crane, they can be classified as fixed connections or detachable connections.

Fixed-coupling spreaders are typically used for lifting containers of a single size. Generally, a movable pulley is mounted directly on the spreader. The slewing mechanism of this type of spreader is usually power-driven, so the crane must be equipped with the spreader’s control circuit. The advantage of this spreader is that it saves hoisting height, and the hoisting device can reduce spreader sway by using multiple lifting points. Additionally, since the sling does not rotate, the simple guide plates provided by the sling can significantly improve work efficiency. Because the sling’s pulleys are directly wrapped around the wire rope, replacing the sling can be cumbersome.

These can be classified as combined slings, generally suitable for situations involving complex container types that are not handled very frequently, or where both containers and other general cargo need to be lifted simultaneously. The sling is pre-assembled with the lifting rings during manufacturing; the user simply needs to hook the lifting rings onto the crane hook. The swivel locking mechanism for this type of sling typically uses a counterweight or ratchet system, requiring no additional power source and making it convenient to install and use. Since crane hooks are generally non-powered and rotatable, the lifting device attached to the hook will also rotate. Therefore, when using this type of lifting device, an assistant is needed below to guide the container and stack it in the designated area. This type of lifting device is not recommended for use on the second floor.

Master-Slave Lifting Device (Master Lifting Device). The sling lifting device consists of two 20-foot and 40-foot lifting devices. The 20-foot lifting device is a fixed-coupling device used to lift 20-foot containers. When lifting a 40-foot container, the 20-foot lifting device is used to lift the container. The support legs are then raised, and the 40-foot container is lifted using the 40-foot lifting device. Both the 20-foot and 40-foot spreaders have a separate power source to drive the rotating locking mechanism. Because the lifting points on the 40-foot spreader are larger and the spreader itself has a greater dead weight—typically over 5 metric tons—the crane’s lifting capacity must exceed 45 metric tons to use this spreader. The advantages are that, compared to telescopic spreaders, these spreaders are less expensive, have a simpler structure, and are easier to maintain.