For the mechanization of loading and unloading, supplying structures and materials to objects under construction, as well as for supporting the elements during their fastening, a jib crane is used - a lifting transport machine, in which the lifting device is fixed on the end of the cargo beam or suspended on a trolley moving along the boom.
Classification of jib cranes
Jib cranes are divided into several types, depending on the scope and design features.
It is customary to distinguish six types of equipment:
- Self-propelled jib crane, in which the boom is mounted on a movable platform or running gear.
- The gantry is mounted on a gantry designed for transport passes.
- The tower, in which the arrow is fixed on a vertical farm, a tower.
- The ship is installed on floating ships for loading and unloading.
- The mast, or derrick crane, has a vertical mast, on which the boom is movably fixed.
- The mounting boom is installed directly at the place of work, stationary, fixed.
Each jib crane instance is assigned an index in which the main design features and technical characteristics are encrypted.
Mobile cranes
Among all groups of lifting machines, the most common are self-propelled jib cranes, which are equipped with various propulsion devices depending on operating conditions and tasks.
The wide distribution of this group of special equipment was provided:
- autonomous drive;
- mobility and high maneuverability;
- the ability to move with the load;
- high carrying capacity;
- ability to quickly transport to another object;
- universality - the ability to install various removable equipment.
Self-propelled cranes have a removable boom, which allows you to change the parameters of special equipment and use it to perform various tasks. The jib type mobile crane is widely used in the construction of bridges and power industry facilities, as well as for loading heavy vehicles before transporting them.
Classification of jib cranes
The main parameters according to which jib cranes are divided into classes are: capacity, type of chassis, drive design and technical features.
According to the type of chassis, special equipment is divided into several types:
- Automotive - lifting equipment installed on a motor vehicle.
- The railway is mounted on platforms moving along railway tracks.
- A crawler jib crane moves on a caterpillar mover.
- The pneumatic wheel is equipped with its own pneumatic wheel chassis, controlled directly from the cab.
- Rail - the same as a railway crane, but independently moving along the line.
Some builders highlight the tractor type, where the boom with lifting equipment acts as a removable attachment. This technique is used to perform work related to the movement of goods in off-road conditions.
Jib Crane Drive
The main working element is the drive, which is responsible for the movement of goods. The most widely used boom crane with a mechanical drive type. In it, all the nodes are driven by an internal combustion engine using diesel fuel or gasoline.
Electric cranes are widely used on urban construction sites, where they are connected to electric lines. For autonomous operation require the installation of a diesel generator. In this regard, special equipment with a hydraulic drive has become popular beyond the city limits, where each machine mechanism is equipped with its own hydraulic engine.
In this case, the cranes are divided into single-motor, where all the working units are driven by power plants operating on one shaft, and multi-motor, where each mechanism receives movement from its own separate engine.
Boom design
Depending on the design, jib cranes are of two types - telescopic and trellised. The first type of boom is a hollow box, inside of which there is one or more retractable beams. If necessary, change the length of the boom hydraulic cylinders push telescopic elements. Such equipment is most often installed on hydraulically driven cranes.
Lattice arrows are divided into four groups:
- rectilinear most common, designed to solve a wide range of problems;
- curvilinear have an inflection, in the area of which a hoist is installed. Such arrows are used to move bulky goods;
- stackable are able to increase their length by installing additional sections;
- articulated - arrows, consisting of an inclined part and a jib joint attached to it by means of a hinge, which significantly increases the outreach of the arrow.
Each type of boom equipment is equipped with a flexible or rigid suspension. In the first case, the jib crane lifts the load with a system of ropes and tackle, and in the second - with hydraulic cylinders.
Luffing Cranes
The main quantity characterizing the crane is its carrying capacity - the maximum mass of the load that the crane can lift.
According to this parameter, special equipment happens:
- light - up to 10 tons;
- medium - up to 25 tons;
- heavy - more than 25 tons.
The amount of load capacity also includes the mass of working equipment - lifting devices, grabs or electromagnets. The load capacity depends on the radius of the boom, taking into account the stability of the special equipment to capsize, as well as the strength of the work units.
Characteristics of jib cranes
GOST 22827-85 regulates the basic characteristics and sizes that self-propelled jib cranes can possess. Characteristics - the main parameters that determine the scope and purpose of special equipment. They are:
- high-altitude - the departure of the hook from the tipping rib, the length of the boom, the lowering depth and the lifting height of the lifting equipment;
- speed characteristics - determine the speed of lifting, turning the load, changing the reach of the boom, movement in working and in a state prepared for transportation;
- tilt parameters - design slope, at which it is possible to move the maximum heavy load vertically at all positions of the rotary part;
- rotation angle indicators - the angle by which the special equipment can turn.
The same characteristics apply to the description of stationary jib cranes. For more information, refer to the relevant GOSTs.