In all spheres of human activity, a beam crane can be used to move heavy loads. It is a load-gripping mechanism placed on a hoist (cargo trolley), which moves along the girder bridge. This type of special equipment is one of the most common. At the beginning of the 21st century, in the territory of the former Soviet Union, according to various sources, from 1 to 1.5 thousand copies were produced annually at 17 specialized factories.
General device
In the general case, the construction of a beam crane consists of span beams, which are often called a bridge, as well as of end supports. Beams and supports are made in the form of a rectangular prism. Inside them, to evenly distribute stresses and ensure stability of the vertical walls, there is a diaphragm - steel plates diagonally welded to internal surfaces.
The beam crane has an upper and lower belt. A rail track is mounted on the upper belt, on which the span beams rest. Here, stops are installed that limit horizontal movement. On the side faces of the beams there are small platforms with a railing for servicing the crane. A cargo trolley is installed on the span beam. A special drive, made according to various schemes, is responsible for moving the structure.
Drive and telpher of the beam crane
The crane movement mechanism is an electric drive with cylindrical or conical support wheels. Cylindrical wheels are used when cargo is transported only in a straight line. Conical supports center the beam crane on the rails and are used if the rail tracks have curved sections. The electric drive can be made according to various structural schemes.
The cargo trolley is a frame structure that relies on the running wheels of the span beams. It has a mechanism for lifting loads - electric or manual, and also provides a limiter for the work of the hook clip. In small cranes,
electric hoists are used as a cargo trolley
, which are rigidly fastened to the frame of the trolley.
Types of beam cranes
Depending on the design features, beam cranes can be supporting, suspended and gantry. The first type is a structure mounted on an elevated rail - vertical racks act as supports on which rail threads are installed. As a rule, a supporting beam crane is used in an open space for transporting bulky and heavy loads.
Overhead cranes are used in enclosed spaces and are installed on beams previously provided for in the building structure. Their main advantage is the small dimensions in height, as well as the possibility of installation in individual sections of the workshop. Their rail track may have a curved shape.
Gantry structures are used exclusively for the transport of multi-ton cargo. They are a structure of vertical supports (capable of moving in the horizontal plane) and horizontal beams. The scope of their application is loading and unloading and construction and installation works.
Boom Tower Cranes
A special place at the construction site is occupied by a tower crane with a beam boom. It is a conventional design for loading, unloading, installation and construction work at various facilities. The boom of such a crane is a truss structure of a triangular, rectangular or square shape.
In the arrow, the upper and lower zones are distinguished. On the lower edge of the farm moves a cargo trolley with the help of an electric drive. In some cases, it can be firmly attached to the beam itself. In this case, the movement of goods in the horizontal plane occurs due to the movement of the boom itself along the guides.
The beam can be located strictly horizontally or at an angle of 30-45 about . A boom crane has a number of advantages. Firstly, the rapid movement of goods in the horizontal direction. Secondly, this is a large radius of coverage of the territory. And finally, the lack of blind spots - the crane can reach the load even in the immediate vicinity of the support.
Characteristics of beam cranes
Depending on the carrying capacity, the beam crane can be assigned to the first (up to 5 tons), second (up to 50 tons) or third (up to 320 tons) group. An electric winch is used as a lifting mechanism. If the gantry crane has rather high lifting capacities, then it is equipped with two hoisting mechanisms: a main one and an additional one.
Another important characteristic of a beam crane is the span. The larger it is, the more massive the structure will be, which is due to the magnitude of the bending moment and stresses arising in the middle of the span. There are multi-span structures that are installed in wide rooms. They rely immediately on several beams - along the edges and in the middle.
Beam Crane Control System
Crane control is most often ground control. An analogue console located in the immediate vicinity of the operator is wired to the hoisting and transporting mechanisms. Another common control method is remote. Details of the beam crane are subordinate to the computer, which, in turn, is controlled by the operator.
Cab-operated cranes are used in large industrial facilities. The driver in the cab manages the process of transportation. Such a crane is equipped with an alarm system for giving signals to slingers, as well as a special landing site.