Jib & Gantry Cranes

Jib & gantry cranes are two popular varieties of freestanding cranes often found in environments such as factory floors. These are usually lighter and smaller cranes used right at work stations or by workers engaged in specific tasks.

Jib Cranes

A jib crane is a free standing crane that looks a bit like the cranes used on construction sites. It usually consists of an arm mounted on a small tower with a winch or hoist at one end. A wire rope or other lifting mechanism runs up the arm from the hoist providing the lifting power.

Jib cranes have the advantage of being free structures that can be easily moved. They are usually only useful for lifting unless they are mounted on some sort of wheeled carriage or rail system for movement.

It is not uncommon for jib cranes to be mounted directly upon walls and other structures. Jib cranes are often used outside because they are not overhead cranes.

Gantry Cranes

The difference between jib & gantry cranes is that a gantry crane is an overhead crane or bridge crane. It usually consists of a crane mounted upon a girder or girders or span held up by supports similar to a bridge.

The difference between a gantry crane and a traditional bridge crane is that a gantry crane is usually mobile. In many cases the gantry crane is mounted on rails or wheels so that it can be moved. In other cases it can be easily broken down for easy movement.

A popular trend in gantry cranes is smaller gantry cranes designed for home and small business uses. A popular brand of smaller gantry crane is the Snaptrac which is small enough for use in home garages and mom and pop shops.

Giant gantry cranes are often used in outdoor industrial facilities such as lumberyards and intermodal shipping yards. In these facilities huge gantry cranes are used to move large objects such as cargo containers.

In some cases the gantry crane will be mounted upon wheels or rails and motorized so it can be moved around. Outdoor gantry cranes maybe moved around a yard for easy lifting.

Gantry cranes usually have a much heavier load capacity than jib cranes and have the advantage of sometimes being traveling cranes. A drawback to gantry cranes is that they take up quite a bit of space on the floor.

Advantages to Jib & Gantry Cranes

The biggest advantage to jib & gantry cranes is that they are free standing structures. This means that their installation involves no construction or engineering work on the building. Since they are not attached to the building, jib & gantry cranes can be used in older structures and larger structures where traditional overhead cranes can’t be used.

Another advantage to jib & gantry cranes is that they can be quickly installed and set up. This makes them ideal for situations when a lifting solution is needed fast.

A disadvantage to jib & gantry cranes is that they can take up quite a bit of space on the floor. This can get in the way of work and manufacturing processes.

Mobile Gantry Cranes

Mobile gantry cranes are about the smallest variants of gantry cranes available. They can hoist loads and be moved from one location to another, where the load will be dropped. Mobile gantry cranes can either be self-propelled or manually moved around. Some mobile gantry cranes can also be dismantled, transported across distant locations and re-assembled for use at the new location, with height adjustable features. Mobile gantry cranes can satisfy both indoor and outdoor use. Indoors, they are mostly found in fabrication workshops, car shops, and in semi-heavy industries application.

Advantages Of Mobile Gantry Cranes

Mobile gantry cranes are about the most flexible among the gantry cranes family. From the point of ordering to final installation, they can be customized, set to adjustable heights, dismantled and assembled as the operation demands. They can also be transported across different locations for use, thus reducing operational costs. In terms of energy consumption, theirs is the lowest of all gantry cranes, with the only disadvantage, being the limit of loads they can hoist.

Mobile gantry cranes can be used in many applications, on ships, fishing trawlers, oil processing vessels, car workshops, manufacturing industries etc. Thy can serve as a cost saving option, instead of a conveyor, in situations where the loads being moved are not of high volume.

Operation

Depending on the industry in which it is applied and the specific company, mobile gantry cranes can serve numerous intended functions. As earlier noted, they can be self propelled or manually propelled, if need be. But, power for hoisting is mostly via electrical Direct Current, or general Alternating Current used by the facility. Lighter duty mobile gantry cranes move loads only in the vertical direction, which is, lifting only, while higher duty types can both lift and move loads. Here, the load can be traversed across the width of the crane.

Also, some mobile gantry cranes can be used in conjunction with other crane types because of their higher mobility level, thus leading to increased operational efficiency. They can be used both indoors and outdoors within a facility. Even if a company is moving shop, all that needs to be done is to dismantle the mobile crane and re-assemble at the new location. This is less expensive than other crane types where you have to call in experts to un-install the large crane, incur transportation costs and also pay for re-installation at the new location.

There are several manufacturers of mobile gantry cranes world over, and they are constantly in competition to provide clients with innovative mobile gantry cranes, more so, since they can be highly customized. This has driven down the cost of the cranes relatively, when compared to other gantry crane types. You can even have your company name embossed on the mobile gantry crane during manufacture. Test runs are much more possible before purchase and they can be easily bought off the counter.

To get the best out of your investment in a mobile gantry crane, you need to incorporate all your lifting needs, send it out to the manufacturing companies and get the best technical bid for your needs. You can even consider using your mobile gantry as a mini-conveyor.

Rail Container Gantry Cranes

Rail container gantry cranes are a form of gantry cranes mounted on rails to aid movement while hoisting heavy items from one position to another. The other form of movement can be on rubber tyres. The first design of a rail container gantry crane appeared in the year 1960. It was designed by Paceco Corporation and referred to as a “Portainer”, coined from the words “port” and “container”. The major loads hoisted by this type of cranes are cargo containers, usually from ship to shore or vice-versa. Thus, they are also referred to as ship to shore cranes.

Operation Of Rail Container Gantry Cranes

Using either electrical AC or diesel engine powered DC as the power source, the trolley in rail container gantry cranes run along rails wile hoisting loads. These rails are located on the top of the boom and girder or at their sides and serve as the support end for moving the hoisted load.

Rail container gantry cranes are best suited for inter-modal container terminals where multiple containers need to be moved from one holding area to another. This can include ship to shore, truck to train, ship to truck, ship to train and vice versa. For these operations, the most important consideration is movement of the container to its desired location effectively and not the speed at which it is moved. One big advantage of rail container gantry cranes is that it allows for better land usage at a shipyard or port and also reduces possibility of ground accidents. This is so since movements by multiple mobile cranes has been eliminated. Also, it increases available stacking area for containers. When offloading containers from ships, the rail container gantry cranes usually straddle the ship, allowing for lifting and moving massive objects over the ship without problems.

For maximum effectiveness at a container terminal, rail container gantry cranes are built with a supporting framework that can manoeuvre across the length of the quay. This framework supports a platform, also known as a “spreader”, allowing the spreader to be lowered to latch onto a container and move it to and from a specific location at the quay. Containers are usually picked one at a time, but some newer rail container gantry cranes have the capacity to pick up four (4) containers at a go.

Two major types of rail container gantry cranes in operation today are the high profile and low profile variants. The low profile variants are most suitable for use when container terminals are situated close to airports, where the high profile type may obstruct the flight path of a plane. In terms of size, rail container gantry cranes are rated with reference to the Panama Canal, especially when the cranes are welded on to and travel with the ship.

We can have a “Panamax”, “Post Panamax” and “Super Post Panamax”. In this light, a “Panamax” crane is one capable of fully loading and off-loading a container ship that can pass through the Panama Canal, while the “Post Panamax” does same for ships too wide to pass through the Panama Canal. The largest, which is the “Super Post Panamax”, is about twice the size and weight of the “Post Panamax.”

How Do Gantry Cranes Work?

In its simplest form, a gantry crane is a member of the fixed family of cranes, with the other main family being the mobile variant. Similar crane types which are members of the fixed family include the overhead crane, jib crane, loader crane etc. A gantry crane, also called a portal crane is a type of crane that has a vertical support on one end, and moves horizontally at the other end, either on rail tracks or on rubber tyres. Usually, gantry cranes lift large or small objects by the means of a hoist which is fitted in a trolley and allowed to move horizontally across an area over which it picks and drops items. Gantry cranes are found in most port locations around the world, as they are used for lifting heavy objects around ships, which is a major advantage for gantry cranes in the shipping and heavy duty industries.

The major types of gantry cranes in use today include the container gantry crane, rail mounted or Electrical Overhead Travelling (EOT) gantry crane and the workstation gantry crane, mobile gantry crane.

Applications Of The Gantry Crane

As earlier noted, gantry cranes are utilized mainly in heavy industries, with its largest types being found in ship-building and port locations around the world. This is because they are specifically designed for lifting very large and heavy objects. At their prime locations, these objects include containers and ship-engines. Smaller gantry cranes can be found in car workshops and are used for lifting engines and their components in and out of cars. These variants are usually mobile units or free standing gantry cranes.

Power for operation of gantry cranes is usually derived from two main sources via diesel engine power generators and electrical power. The diesel powered generators can be found at the top of the crane and emits Direct Current (DC) while the electrical power source is usually located at the dock. This is also referred to as shore power and emits Alternating Current (AC).

Gantry cranes can be classified either based on their operational capability and size or physical mode of operation. The most advanced of the pack is the automated gantry crane, also referred to as the Stacker. It is usually unmanned and controlled from a remote operations center. This is used when volumes of large loads, especially containers are to be moved between two holding bays, e.g. from ship to train or truck to ship and vice versa. In terms of size, the rail container gantry cranes are the largest available anywhere in the world. Two famous gantry cranes nicknamed Samson and Goliath, built in 1974 and 1969 respectively are one of the largest in the world today. In combination, they have a lifting capacity of over 1,600 tonnes at heights up to 70metres. They currently reside and execute lifting assignments in the largest dry dock in the world at Belfast.

The hoist, that is, load lifter on gantry cranes can either be located in a fixed machinery enclosure or on a trolley. Trolley hoist systems usually run horizontally along rails and can be fitted either on a single beam or on two beams, that is, a mono girder and twin girder respectively. When gantry cranes run on rubber tyres, there is no need for a rail system, thus reducing cost and earth impact.