Understanding the key components and terminology related to overhead cranes and gantry systems is essential for those working with or around these machines. Here, we explain some of the most common terms you might encounter.
Single Girder Crane
A single girder crane features a bridge, the part that includes girders, trucks, end ties, and the drive mechanism. This bridge supports one or more trolleys, which carry loads across the span of the crane.
Crane Girder
The crane girder is a key part of the structure—a metal beam on which the crab or hoist head of a traveling overhead crane runs. It provides the primary structural support for the crane’s lifting mechanism.
Double Girder Crane
Unlike a single girder crane, a double girder crane has two bridge girders. The hoist trolley typically moves along rails attached to the top of the crane girders. This design is useful for handling heavier loads or longer spans.
Jib Crane
A jib crane consists of a horizontal arm, also called the jib or boom, that extends from the crane. The jib supports a moveable hoist and can be mounted on a wall or pillar, offering great flexibility in material handling over short distances.
Gantry Crane
A gantry crane is similar to an overhead crane but with key differences. The bridge is supported by legs that move along fixed rails or directly on the floor, rather than being attached to a runway. This type of crane is typically used in outdoor environments or large warehouse spaces.
Monorail Beam Crane
A monorail beam crane offers a simpler alternative to conventional overhead cranes. Monorails typically move materials in a straight line within confined spaces but can be designed with curves to allow for more flexibility in material handling.
Safe Working Load (SWL)
The Safe Working Load (SWL) is the maximum weight or force that a lifting device can safely lift, lower, or suspend. Staying within the SWL ensures the equipment operates without the risk of failure.
Working Load Limit (WLL)
The Working Load Limit (WLL) refers to the maximum load that equipment can safely handle, as determined by the manufacturer. It is always set significantly below the force required to cause failure, ensuring a margin of safety during operations.
Trolley
The crane trolley is the part of the crane that holds the hoist. It moves along the bridge rails, carrying the hoist across the crane’s span. The trolley is powered by motors, which allow it to move back and forth, aiding in the precise placement of loads.
Hoist
The hoist is a vital component used to lift and lower loads. It is attached to the trolley and includes a motor, brake, gearbox, load rope, and hook block. Depending on the crane’s design, the hoist can be mounted either above or below the crane beams.
End Carriages
End carriages are located at both ends of the crane bridge. They contain the wheels that move along the crane runway, enabling the longitudinal movement of the bridge. The design and capacity of the end carriages significantly impact the crane’s overall efficiency and stability.
Overhead Crane Span
The span of an overhead crane refers to the horizontal distance between the rails on which the crane travels. It is a critical factor in determining the crane’s operational range and overall capability.
Crane Gantry
The crane gantry is the structural framework that supports the overhead crane. This system typically consists of columns and track beams, with the crane rail attached to the top of the track beams, allowing the crane to move smoothly along the runway.
Understanding these fundamental crane terms helps operators and engineers make informed decisions when choosing or working with different types of cranes. From the type of girder to the importance of the Safe Working Load, each component plays a crucial role in the safe and efficient operation of overhead cranes and gantry systems.
