Tower cranes - classification and operation
Specifics of tower cranes
Tower cranes are among the largest transport machines. They are most often used in construction works. Read the article and find out what types these huge machines are divided into.
Division of cranes
The basic criteria for the division of tower cranes are parameters such as the location of the slewing mechanism, the type of base, the type of mounting and the boom. The structure of a crane consists of a vertical mast located on a stationary or mobile base. It also includes a horizontal or pivoting jib, also known as a support arm, a lifting cable (which lifts loads) and a base. These devices also contain drives, each with a different task. They are mainly responsible for the travelling movement of the base, the rotation of the boom, the lowering and raising of the hook, the movement of the jib or the swinging movement of the boom.
Classification by type of base
In this category, tower cranes are divided into stationary i mobileThis is the basic division. Stationary ones do not have a drive-through function. They are mounted on a portal, a trailing anchor or a cross. Mobile ones, on the other hand, are provided with a vehicle or crawler chassis.
Classification by type of assembly
These cranes are divided into quick-assembly cranes, which do not require auxiliary cranes to operate, and assembled cranes, which require auxiliary cranes for assembly.
Classification by boom type
In this section, a distinction is made between cantilever booms and pivoting booms, or cantilever arms. A cantilever boom is a so-called movable arm that acts in a rotational manner. Cantilevered booms can withstand heavy loads and are designed to transport very heavy materials. The cantilever in this case is called a jib, and it moves along the jib by means of two cables. In pivoting booms, the linkage is mounted at the very end of the boom. They work well in confined areas and those with limited space or dense buildings.
Classification according to the location of the rotation mechanism
In this category, top slewing cranes and bottom slewing cranes are distinguished. Mechanism responsible for the slewing motion in top slewing cranes is built into the top of the tower. It only rotates with the boom, counter-boom and head. The mast remains vertical and stationary in this case. This type is used for medium and large projects with long lead times. As for the bottom-rotating cranes, their mechanism is located at the bottom of the tower. It rotates the entire crane in turn, with the portal remaining the only stationary one. The assembly of these machines takes place automatically.
Advantages of crane authorisations
Operators and maintainers of this equipment can expect to earn higher salaries. In order to become such a specialist, it is necessary to complete a training course and take a state exam, taken before a commission.
Questions and answers
Which parameters should be considered when choosing a crane?
When choosing a crane, it is important to look at the lifting capacity, overhang, useful lifting value, working and tipping torque of the crane.
What is the function of the rotation brake release?
It allows the boom to be positioned with its back to the wind, disregarding any change in its direction.
What is a working moment?
It is the product of the lift and the overhang of the machine. It is expressed in tonometres.