Container Twist Lock
In simple terms, Twist Lock is a mechanical locking device firmly fastened at the corners of a shipping container. These mechanical devices are used to secure containers on ships, semi-trailer trucks, and container trains. It also helps to lift containers by cranes and side-lifters. They are conical in shape and primarily serve the purpose of positioning and fastening containers during transportation in ships. It incorporates a rotating mechanism that secures itself into each corner casting of the containers, and are mostly used on the deck of a vessel.
These devices are strong, durable, and work efficiently in spite of long periods of exposure to extreme weather conditions that the containers undergo during long voyages and storage.
Types of Twist Locks:
* Standard Intermediate Twist Lock
* Semi-automatic Twist Lock
* Fully automatic Twist Lock
Conventional/Standard Intermediate Twist Lock with a handle are used to secure containers to the deck. Such Twist Locks are locked and unlocked with operating rods as shown in the illustration above.
Semi-automatic Twist Locks are used between two containers to join and secure them in place.
Semi-automatic Twistlocks are locked automatically but can be unlocked only by manual intervention by operating the operating rods.
Fully-automatic Twist Locks are placed in the lower corners of the container at the pier. They lock automatically when the container is placed on the top, and unlocks by itself when the container is lifted.
Although such mechanical devices are made of the best quality raw material, they require periodical maintenance to provide an extended period of serviceable life. This includes greasing the moving parts and inspecting the working of the mechanism and effectiveness of the spring action. As a result of wear and tear, the cones in Twist Locks suffer damage. In such instances, the entire Twist Lock unit should be replaced. By unscrewing the bolts and nuts, the unit can be opened to remove the cone assembly, spring and, wire handle for a close examination.
During the voyage across seas, ships undergo extreme weather conditions and turbulence resulting in strong motions in these vessels. Twist Locks aid in securing the containers to the deck and provide the necessary reinforcement, strength, and stability to these large vessels that navigate thousands of nautical miles across oceans to reach their destination safely and unload the cargo.