Gantry Crane

A Gantry Crane is a type of overhead crane where the main bridge girder, which supports the trolley and hoist, is itself supported by freestanding legs that travel on rails at the ground level. From an industrial braking perspective, a gantry crane is a multi-axis system where each axis of motion requires a dedicated, purpose-engineered brake to ensure operational safety and control.

The braking system is typically segmented by function:

1. Hoist Brake: This is the most critical safety component. It is a primary, fail-safe (spring-applied, power-released) brake, often a large electro-hydraulic drum brake or a robust electromagnetic disc brake. Its sole purpose is to securely hold the full rated load in a static position whenever motor power is removed, either intentionally or due to a power failure, thus preventing a catastrophic load drop.
2. Trolley Travel Brakes: The trolley moves the hoist horizontally along the main girder. It is equipped with its own set of smaller fail-safe brakes. These brakes provide controlled dynamic deceleration for precise load positioning and also act as parking brakes to hold the trolley stationary, preventing it from drifting due to slight inclines, drive backlash, or external forces like wind.
3. Gantry Travel Brakes (Long Travel): These brakes are mounted on the main drive wheels that move the entire crane structure along its ground-level rails. Given the immense mass and inertia of the crane, these are powerful brakes (often disc or drum) responsible for bringing the entire structure to a controlled stop (service braking) and for securely parking it. They are fail-safe to prevent the crane from rolling away in a power outage.

For large gantry cranes operating outdoors, such as those in ports and shipyards, an additional layer of braking is often required: Storm Brakes. These are ultra-high-force, often hydraulically or mechanically applied rail clamps or wedges that are engaged when the crane is parked during high winds. They are a separate system designed purely for static holding against extreme environmental forces and are not used for dynamic stopping.

In essence, the safe operation of a gantry crane is not dependent on a single brake, but on a coordinated system of specialized brakes, each designed for the unique forces and safety requirements of its specific axis of motion.