Lifting, lowering and moving of heavy objects in many industrial plants, is performed by heavy machinery. Gantry Cranes are one type of these machines that has some advantages over the others as far as utility, cost, and mobility. They may be the best choice for your operation.
The element of these machines responsible for the actual lifting or lowering of material is the hoist. It extends or retracts a wire rope or chain, from which hangs the material to be moved. Weights of up to 150 tons are lifted by some units.
This hoist can be built into a trolley, which will traverse along a rail or dual rails fitted under a horizontal, overhead bridge beam. This arrangement allows the material to not only be lifted and lowered, but also moved horizontally along the beam and replaced at a different location.
A third plane of movement, perpendicular to the last, is possible when the bridge beam is not fixed, but can travel on tracks placed along the outside edge of the work space. This equipment can be supported by concrete footings and structures built into or against a factory, shop or plant’s walls.
The machinery straddles the heavy objects being lifted, and the work area. The types of industrial environments where these heavy lifting machines are commonly employed include, dry docks, locomotive repair shops, docks, pulp mills, steel yards and concrete fabrication plants. Smaller versions can be found in smaller plants and shops. Sizes are variable from small mechanical units to large 150 foot span electric powered versions.
Gantry cranes work in a similar manner. They are of similar construction except that the bridge beam is not supported by concrete footings and supports fixed to the building. They have upright supports, similar to stilts, incorporated into the machine itself. The unit travels on the floor, on inverted angle iron. Some versions travel on wheels or rubber tires. This allows access with carts and forklifts without obstruction by tracks mounted on the floor. It also makes them portable and movable.
Variations include single leg styles which combine elements of both types. They have supports on one end, and run along footings on the other. Cantilevered types have support only on one end, and project out over objects like docked cargo ships.
Due to the cost of the uprights, these units are usually more expensive. The overall project cost can be considerably less, however, due to the absence of the concrete footings and supports for runways. This is especially advantageous with long runway requirements.
Additional cost advantages are realized if the plant is rented and moving in the future is anticipated. Also consider the possibility of moving the machine between two or more sites for work. This type of unit can also be used inside the building and out into a yard.
These powerful electric material lifting and moving machines have been indispensable in a variety of industrial applications. Gantry Cranes often are less costly and more versatile than other lifting machine types.