Device of a tower crane. Installation and dismantling of tower cranes

No major construction site is complete without tower cranes. What are these giants made of? How do they move? How does the installation of a tower crane? For more information, see the article

Crane tower

A lifting machine with an arrow located at the top of a vertically fixed tower, which serves to capture and move large-sized cargo, is called a tower crane. Any tower crane has the following parameters: boom reach, load capacity, lifting and lowering speed, lowering depth, speed of movement, speed of rotation of the tower, etc. The components of a tower crane include: a tower, a turning platform with a boom and cargo winch, a pivot mechanism, a device for lifting and lowering cargo, a mechanism for moving the machine, a mechanism for changing the departure of the boom, etc.

Tower crane boom

The boom of a tower crane is a mechanism by which it reaches a load located at a certain distance from it. There are lifting, beam and articulated boom tower crane.

The advantages of the first type of crane arrows include the fact that they are small in size and weight. They are also easy to install and transport. The disadvantages of such arrows include the fact that it is impossible to move the load horizontally to change the departure of the hook. Meet hanging pendant with racks, suspended from the jib and monotomidae options.

The beam type of arrows has 2 types: suspended and hammer-shaped. Most of all, suspended beam arrows are used in construction. Along the lower part of these arrows, which are an I-beam, the rollers of a cargo truck are moved, which serves to capture and move the cargo. Moldovenii braced boom are not widely used because of large size and mass of the structure.

Articulated arrows consist of two parts (main and head) and belong to the type of combined arrows. The head part of an articulated boom is called a jib. Tower cranes with this type of boom have two hook suspensions. The flyout of the articulated boom can be changed in two ways:

lifting the entire boom;

the combination of lifting movements of the boom and moving the cargo truck along it.

Counterweights

On the opposite side of the boom are counterweights that serve for the stability of the crane. On cranes with a rotating tower, instead of counterweights, special struts are used, with which the branches of the boom ropes are removed from the tower. On cranes with a non-rotating tower, the counterweight is placed at the end of the counterweight console.

Winches

Winches, as well as counterweights, are located on the opposite side of the boom. The construction of crane winches consists of an electric motor, a drum, a brake and a gearbox. There are cargo, boom, and truck winches. Modern cargo winches have several lifting and lowering speeds. Several cargo winches are installed on separate tower cranes: for large, medium and small loads. Boom winches are used to change the hook departure and the angle of the boom. Bogie winches are used for moving cargo trucks along the beam boom

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Steel rope

When operating a tower crane, steel ropes play one of the main roles. Ropes perform the function of the crane's traction organs when lifting the load and the boom. Steel ropes are used for mounting and Dismounting a tower crane, when extending the tower, for turning the crane, and for moving a cargo truck along the boom. The rationality of using steel ropes is due to their high strength, flexibility, and load capacity at a relatively low own weight.

Blocks, tackles, reels.

 Blocks, tackles, reels are used to connect the rope with the lifting mechanism. All these mechanisms are designed for lifting and lowering loads. The block, as the simplest mechanism, is a wheel with a chute for placing the rope. The disadvantages of blocks include the fact that they almost do not give a win in power. Blocks can be movable (they move with the load) and stationary (they are used to change the direction of movement of ropes). The tackles are a mechanism consisting of several moving and stationary blocks which are fastened by rope. Due to the low speed of lifting loads polispast allows you to get a big gain in strength. The drum is made in the form of a cylinder with a hollow interior. The design of the drum uses screw grooves, which serve for less wear and better laying of the rope.

Moving the tower crane

If possible, tower cranes are divided into: mobile (self-propelled and trailed), stationary (attached), self-lifting (mounted on the frame of a building under construction). In order for the tower crane to be able to move, various chassis are used for it: automobile, pneumatic, tracked, walking, rail.

In most cases, the movement of self-propelled tower cranes is carried out by moving the running trolleys along the crane tracks (rails). To distribute the load, the crane's running trolleys are combined into balancing ones. The four-wheel crane is equipped with a movement mechanism with a two-wheel drive. Bogies with eight or more wheels are individually driven. The driving cart is equipped with a motor and gear reducer,and anti-theft devices are installed on it from the end. Anti-theft grips prevent the crane from moving out of operating mode by means of wind. One of the trolleys also has a button for turning on and off the track limiter, which is triggered when the crane hits the rails over the limiting line.

Installation and dismantling of the tower crane

In practice, quite a large number of ways to install a tower crane are used. A different method is used for each specific situation. The main factors that influence the choice of a particular method are: the height of the tower and the length of the boom, the conditions for installing the crane, and the duration of Parking.

If the situation requires frequent transportation of a tower crane from one construction site to another, use a special design crane that allows you to fold the machine without disassembling it. The disadvantage of such a crane is that its installation requires a significant space on the construction site.

For rotary cranes, a method of independently lifting the tower together with the boom using a polispast is used.

The universal method of mounting a tower crane involves the use of a stationary mast. Separate structures are mounted in parts in the desired sequence. In cases where the use of the mast is not possible, installation is performed using a light creeping crane.

Dismantling of tower cranes is carried out in the reverse order of installation.