Basic Structure and Design
Rigid Frame: Fixed frame spreaders have a sturdy, non - adjustable frame. This frame is typically made of high - strength steel or other durable materials to withstand the heavy loads and stresses involved in container handling. The frame is designed with precise dimensions to match the standard sizes of containers, ensuring a proper fit during engagement.
Twist Locks: These are the key components for attaching the spreader to the container. There are usually four twist locks, one at each corner of the spreader frame. Each twist lock consists of a locking mechanism that can be rotated to engage or disengage with the corner fittings of the container. The corner fittings are standardized components located at the four corners of a container, providing a secure attachment point for the spreader.
Lifting and Moving the Container
Load Transfer: Once the twist locks are securely engaged, the weight of the container is transferred to the spreader. The spreader, in turn, is attached to the lifting equipment (such as a crane hook) through a bail or other lifting attachment points on the frame. The lifting force is then applied, and the container is lifted off the ground or the stacking surface.
Movement: The crane operator can then maneuver the container to its desired location. The fixed frame spreader provides a stable platform during this movement, ensuring that the container remains level and secure. The rigid frame helps to distribute the load evenly across the four corners of the container, reducing the risk of tilting or swaying.
Disengagement from the Container
Positioning for Release: When the container has reached its destination, the spreader and container are positioned above the stacking surface or the location where the container is to be placed.
Unlocking and Lifting: The twist locks are then rotated in the opposite direction to unlock them from the corner fittings. In an automatic or semi - automatic system, this can be done with the push of a button or the activation of a control. Once the locks are disengaged, the spreader is lifted slightly.
