Bridge cranes and jib cranes are the unsung heroes of modern life, their sheer lifting power and capacity ensuring that shops are stocked and our homes built. Docks, warehouses, the construction industry and auto-repair shops make use of the technology, moving the heaviest of loads, easily and effortlessly.

Where load capacity and speed are the major factors, bridge cranes are the preferred option, moving heavy cargo from one place to another quickly and efficiently. No container port or large warehouse could operate without this essential logistical equipment.

Jib cranes, on the other hand, sacrifice some lifting power for precision and the ability to operate through a 180^o or 360⁰ arc. The huge gantry cranes that dominate the skyline of many shipyards are a sub-type of gantry cranes. These wheeled behemoths run upon rails embedded in the ground rather than overhead runners.

The bridge crane is the larger type that hangs from suspended rails, and is most commonly found in container ports, factories and warehouses, moving huge loads at the cost of a little maneuverability. Bridge crane are constrained by the rails to specific paths, so lack the ability to drop loads directly onto racking, with precision. However, the high speed, ability to cover large areas and the relatively high load capability ensure that this type is worked hard.

Bridge cranes consist of a girder spanning the gap between two runners. These tracks are either suspended from the ceiling or supported upon sturdy columns. Bridge cranes supported by columns can generally carry proportionately more weight, but the columns can be obtrusive and impair operations, so there is always a trade off.

The entire overhead crane apparatus moves freely along these tracks, and a chain hoist suspended from the girder provides the vertical lifting. This hoist is free to move backwards and forwards along the girder, allowing lateral manipulation of loads. This set up ensures that the entire overhead crane assembly can handle large loads at high speed, and cover large distances, useful for dockyards and large warehouses. Bridge cranes vary in size, from small cranes designed to lift a few hundred pounds, to the large dockyard cranes with an incorporated cab for the operator.

Bridge cranes are available as two basic two types, one with the mechanism suspended underneath the rails, the other with the runners sitting on top of the tracks. The latter type is more common, because it can handle heavy loads more easily, but suspended bridge cranes are excellent where headroom is limited, maximizing the available space.

The jib crane is an extremely common type, offering an excellent compromise between lifting power and precision, its arc of operation ensuring that it can operate in areas that bridge cranes cannot. Jib cranes are available in a wide range of sizes, from small types used to lift engines from cars, to the huge industrial machines found upon construction sites and dockyards.

The underlying layout of a jib cranes consists of a solid boom shackled to a fixed pivot point. In turn, this pivot is securely mounted onto a wall or on top of a freestanding column. This pivot moves freely, allowing 180 or 360-degree rotation, and a wide arc of operation. The lifting is performed by an incorporated pulley or motorized chain hoist, which can slide along the book and offer a large footprint of operation.

Jib cranes allow the payload to be manipulated with a high degree of precision. The huge tower cranes found on building sites, and mobile cranes mounted upon trucks and trains are based upon the jib crane layout. They offer even more in terms of manuverability and utility.

The main disadvantages of jib cranes are that they are restricted in movement to a specific arc, and they handle proportionately less weight than a suspended crane, due to their more unstable configuration. However, their precision ensures that they are essential logistical equipment in a wide array of industries.

Many processes use suspended cranes and jib cranes in synergy, combining the advantages of both whilst removing the disadvantages. Ports are one example of where bridge cranes perform heavy lifting across large distances, whilst jib cranes manipulate the load into accessible positions.

As an example, jib cranes are often used to empty ship's holds, because they can reach out over the edge of the quay. They dump the load on the quayside, where gantry cranes move the loads quickly, delivering them to the correct warehouse. Here, another jib crane will move the load to the loading area, where the staff can break it down and move it to the correct area with forklifts, side-lifts, pallet trucks and, finally, pallet jacks.

Jib Cranes and Bridge Cranes – The Foundation of Logistics

Jib cranes and bridge cranes form the background of the international transportation of goods. From the site of manufacture to the final point of storage and sale, these workhorses combine lifting power and subtle manipulation of loads. Of course, not all cranes are the huge monsters found on docksides, and small businesses and even homeowners often find it useful to invest in a small crane, for loading back up generators, motorbikes and cement mixers onto a truck.