Every construction site needs cranes for various tasks, and they come in a wide variety of sizes, shapes, and configurations. For example, a tower crane’s long boom can reach heights of 500 feet or more while a crawler crane can carry loads up to 640 tons over land. A mobile crane is placed on wheels or tracks and can travel along one level if the load weighs less than 10 tons or climb an incline if it weighs less than 30 tons.
There are two types of cranes used in construction work, namely the tower crane and the mobile crane.
The tower crane is fixed. This means that it does not move easily from one place to another. It is also known as a fixed crane or a gin pole. The boom of a tower crane can extend up to 350 feet in the air depending on its size. Tower cranes are used for lifting heavy loads in construction sites and it can also be utilized in cargo loading and unloading operations at ports or harbors.
The mobile crane is more versatile than the tower cranes because it has wheels or tracks so that it can be moved easily from one place to another. Also, its mobile structure allows it to be used in different positions. It can easily be used for lifting and placing load. It is also known as moving cranes.
A tower crane is a fixed-base, self-propelled lifting machine which can carry loads up to 5700 kg (10,350 lb), supported by a single mast, or sometimes by two pylons and a vertical arm. Its lengthwise load capacity is about 300 m (984 ft). To achieve greater height, a tower crane is equipped with a boom with an extension of 12 to 100 m (39 to 328 ft). The boom is usually combined with a jib for additional height.
A tower crane may also have a mobile stage, and sometimes a lattice-like metalworking platform called a "boom-jib". This combination is known as a "tower truck", or "tower crane mounted on an EOT Crane Carrier".
More about mobile cranes
It is used in limited work areas where there is either no room for movement or access via truck mounted equipment, or where it would be too dangerous to operate these machines due to confined spaces, live wires, etc. The mobile crane is used to raise heavy loads and lower them when needed. It comes in various sizes depending on the lifting capacity. The mobile cranes can be operated manually or with electric controls. The design of the crane varies greatly from one manufacturer to another, but usually they consist of a base frame with uprights and a boom. A pivot point about which the boom swings, and wheels or tracks for smooth movement. The wheeled cranes can be moved either by hand or via wheel cart on the ground.
Truck Mounted Crane
The truck mounted crane is similar to the mobile one except that it is not designed to move freely but is mounted on a truck. It may be placed anywhere convenient and used to lift loads of any width, but mostly used for smaller ones. The crane remains stationary and some movement in the lifting takes place by using hydraulic cylinders instead of a wheeled vehicle to which the cab and boom are attached. It can be driven manually or powered by electricity.
The tower cranes are heavy duty machines which are mainly used in construction projects where a payload of around 6000 kgs or more needs to be lifted. These powerful cranes are usually used at construction sites or in heavy industrial plants where moving oversized loads may not be an option. These cranes are mainly operated by a crane driver who sits inside the cabin with the controls while a load handler waits on the ground to receive items to be lifted and carry them to its destination using hand trucks.
It is similar to the tower crane, but it is designed for temporary use only and is used when moving through narrow or confined areas with limited clearance. It consists of a cab which contains the operator's seat, engine, and controls as well as lifting mechanism, which is similar to that of the tower crane except that it does not have any sort of lifting capacity.