What is a tower crane?
Almost no urban construction or large-scale repair could be handled without a tower crane. In this article, we will discuss tower crane characteristics and how they work.
Of course, since childhood everyone knows what a tower crane looks like – literally, a vertical tower, including the driver's cab and the boom. During operation, the crane moves along the rails, rotates, controls the outreach of the boom and performs all the actions necessary to lift and move cargoes.
The basic structure of the crane is the tower, which is where it gets its name. The tower is mounted on a rotating platform or a supporting part, and the height of the tower determines the maximum height to which a load can be hoisted, which is quite logical.
There are two variants of the tower crane: rotating and nonrotating. In the first case, there is a pivoting device at the bottom of the gantry or the supporting part. The turret, boom, slewing mechanism, counterweight and platform with winches belong to the rotating platform.
If the pivoting device is at the top, the slewing part consists of the counterweight, slewing head and boom, and the platform with the tower does not rotate.
These towers cranes in turn are called either lattice or telescopic.
Lattice boom cranes have solid structures, consisting of belts and struts. For attached stationary cranes, a foundation or a portal is used for the base; mobile cranes utilize an undercarriage.
Telescopic cranes have two sections – the supporting outer section, which is attached to the turntable, and the extending inner section.
There are three types of booms depending on the design:
Articulated booms. They consist of a main part and a head part. Cranes with this boom use two crane hangers, which are used to increase the hook reach and lifting height.
Hoisting. The boom is set obliquely to the horizon, and there are blocks with cargo ropes at the end of the boom. This is the most popular type of cranes.
Girder. They consist of two belts with the lower belt driven by a trolley, and the booms are set at an angle of 30° to 45° or horizontally.
Only mobile models are equipped with an undercarriage, which comes in four types:
Rail - the most common type, with the number of wheels varying from 4 to 32, dependent on load distribution
Automotive - cranes on car chassis
Pneumatic tire – various types of chassis
Crawler - moves on tracks
Of course, all tower cranes with an electric drive are equipped with safety devices:
● anti two block device,
● bridge and cart limiters,
● load limiter,
● cabin door locking,
● emergency switch,
● crane protective panel,
● anemometers and signaling devices - for outdoor cranes.
Modern cranes have a lifting capacity of 75 tons, although 5-25 tons with an outreach of up to 40 meters is in most cases sufficient. There are models with outreach up to 80 meters. As for the lifting height, tower cranes have a max of 220 meters, while the max for stationary cranes is 90. They also differ in terms of lifting speed, which can go up to 200 meters per minute, depending on the model. And the speed of movement at the site is usually in the range 10 - 30 meters per minute
What kind of crane you should choose depends on many factors, and skimming a couple of articles isn’t going to get the job done. It’s better to contact a professional and make a joint decision.