Lifting crane

The first crane appeared in 1830 in the UK. It was a steam version. A more perfect model, already hydraulic, was designed after 17 years. But if earlier, when the first cranes appeared, the work was done largely by manual force or partial mechanization, but today any construction site, from small to large, has a construction crane at its disposal.

Some general information

It is necessary to understand that there is no such device as a construction crane. There are cranes. This term was given by Gosgortechnadzor. The definition was approximately the following: a crane is a machine that has a load gripper (hook, grab, etc.) that is used to lift and move heavy loads.

Today such equipment is actively used in construction. In principle, from an economic point of view, this is quite profitable. A modern crane can lift a load of more than 1,000 tons, but typical 50-tonners will work for the construction.

Operation cycle

It should be understood that for the lifting and moving of the load, the operator must perform simple manipulations (cycles). At the first stage, the cargo is seized. If it is a concrete slab, then it is tied, and for its lifting a hook is used. If it is loose material, the work is carried out by a grab. The second stage is the working stroke. It consists in the direct movement, as well as the unloading of the material being transported. In fact, this is the most critical stage, so the work must be done smoothly and without jerking. The final stage is idling. It implies the return of the load gripper to the starting position. By the way, the working stroke consists of three stages: acceleration, steady motion and braking. The first and third stages are the most important, since it is on them that dynamic loads appear and, therefore, the risk of damaging the transported cargo.

Construction crane and its construction

By and large, the unit consists of several important components. Let's look at each of them:

• Metalware is the foundation of a construction crane. All that can be attributed here are spans, supports, arrows, etc. It is worth noting that they are box-type and lattice type. In construction, box metal structures are often used.
• The lifting mechanism consists of a flexible lifting device. This can be a rope or chain. Here also it is necessary to include a load-gripping device (a loop, a grab, a hook, etc.). In building load-lifting technology, hook cranes are most often used.
• The lifting device is not automatic (hook or loop), requires minor manual work, as well as automatic (electromagnet or pneumatic suction cup).

As you can see, the construction crane is quite a complicated device that needs constant supervision and replacement of ropes, hooks and other parts and components.

Classification by design and movement possibilities

Immediately it is worth noting that there is no single classification that reflects the full essence. The fact is that modern cranes can combine several functions at once. So, there are the following construction cranes depending on the design:

• Arrowheads - the load gripper in this case is mounted on the boom. It is these cranes most often used in construction, as their maneuverability and mobility allows you to perform all the work quickly enough.
• Bridge - metalwork is a bridge to which a load-lifting organ is suspended.
• Cable type cranes.

As for the possibility of moving, it makes sense to say only about two main types: stationary and self-lifting. The last kind is just used for building construction. Its peculiarity is that it is installed on the erected object. As the building grows, the crane is raised using special mechanisms. Although in recent years, mobile boom truck cranes are increasingly being used, which are largely in the lead in technical characteristics. Such a construction crane is adjusted if necessary and easily moves to another object. Now let's go further.

Construction tower cranes

Cranes of a tower type are the most rational in civil and industrial construction. Due to the fact that they allow installation, dismantling and transportation by vehicles. This allows you to reduce production costs by speeding up the work. But sometimes such a tap is not used because of insufficient space. In this case, a quick-mounted tower crane is used. The construction lift of this type is good because it does not need a lot of space to install it. However, such a lifting device can not be used at a building height above 30 meters. It is interesting that in one shift the crane can be dismantled and assembled at another construction site with minimal production costs. To date, this is one of the most appropriate solutions after the truck cranes.

Pneumo-wheeled and crawler crane

The variant working on the pneumatic wheel chassis is good because it has increased cross-country ability. In principle, a construction crane, the photo of which you can see, is used in close proximity to the object. This was achieved by installing several controllable axes. In addition, the operator's cabin is quite comfortable. There is a computer that practically completely excludes the human factor, the air conditioner, etc. of the system.

There is also a crawler crane. It is mounted on a crawler chassis. Despite the high cross-country capacity, such equipment is capable of efficiently operating only at previously prepared sites. Transportation is carried out using a special trailer, which increases operating costs. That's why not such a construction machinery is used everywhere. Cranes of this type are used only where any other is not suitable.

Conclusion

So we figured out what a construction crane is. You can find photos of several popular models in this article. I would like to note that today such lifting equipment is used everywhere. It allows you to reduce the traumatic risk of production and reduce the amount of manual work. There are a large number of cranes, this applies to both their types and their carrying capacity. Some are designed for quick work and mobile moving to another object, while others, on the contrary, pick up slowly, but rather heavy loads, and stand on the objects for weeks or even months.