What happens to the hook and load when retracting the boom on a telescopic boom crane?

When retracting the boom on a telescopic boom crane, the hook and load decrease their height off the ground. This action occurs because retracting the boom effectively shortens its length. As the boom retracts, the angle of the boom changes, causing the hook to move downward as the load is pulled closer to the crane's base. This movement results in a decrease in height for both the hook and the load, bringing them closer to the ground, which is important for maintaining stability and control during operations.

The mechanics of a telescopic boom are designed such that when the boom is retracted, the load experiences a corresponding vertical descent due to the geometry involved. Understanding this principle is crucial for safe operation and effective maneuverability of cranes, as it directly impacts load handling and clearance requirements.