A crane is a machine used to move objects from one place to another, such as lifting, lowering, and moving horizontally. The word crane was given to these machines because of the similarity of the appearance of such machines with a type of long-necked fish-eating birds. The first building cranes were invented by the ancient Greeks and were driven by humans or load-bearing animals such as donkeys and horses. This type of cargo was used to build tall buildings; this type of cargo developed over time. In the middle ages, port cranes became popular for loading and unloading ships, and with their structure, they helped to transport goods. Construction cranes were first made of wood and later of stone.
The first type of industrial crane was used in ancient Egypt about 4,000 years ago to move water from wells. They are made of wood and are known as Shaduf. This type of early machine consisted of horizontal support with two vertical supports and a rotating arm. For balance, on one side was the balance weight and on the other side was the swivel arm, which moved water or goods.
In the 16th century, the Jib was added to the Boom, the main arm, to increase the load length of the crane. The following figure shows Boom and Jib.
These advances continued, and in the nineteenth century, internal combustion engines and electric motors were used to increase the lifting capacity of cranes in their structures. Their bodies were also converted from wood to steel and their strength increased significantly.
Today, all types of cranes are produced and marketed. Various materials are used in the construction of cranes; the most important material used in the construction of cranes is steel. Steel is an alloy of iron and carbon to which elements such as chromium, nickel, molybdenum, vanadium, and titanium are added to increase its strength. In addition to the above materials, other materials such as synthetic plastic are used to make tires, copper in electrical construction and wiring, semiconductor elements such as germanium and silicon are used in the electrical circuits of the device.
Types of cranes:
Chain overhead cranes (Suspension cranes)Suspension overhead crane is the best choice when you have limited space in terms of bridge and winch installation on the roof of the hall and at the same time need the maximum height of the lift. In this type of crane, the longitudinal guides are placed as a pendant on the lower wing of the carrier beam and the bridge or bridges are connected to the guides.
Suspension overhead cranes
Overhead cranes are used for vertical and horizontal load transfer in warehouses and industrial halls. These cranes usually have two parallel rails that move horizontally (limited in six directions) along the crane hall.
This type of crane is considered due to its lower construction cost, less occupied space, and less pressure on the hall rails and is widely used in the industry.
This type of crane is the best option for halls that have a suitable space. Duplex overhead cranes have a high height for vertical displacement. Another advantage of this type of cranes is the presence of an optional corridor in the crane body, which in addition to easy access and the possibility of repairing trolley parts (trolley), also provides a suitable possibility for repairing and replacing hall lamps, hall heating facilities, and power lines.
Gantry cranes are used to move loads outdoors and indoors. Gantry cranes have the ability to install single and double bridge tow ropes in different working groups.
Advantages of gantry cranes:
Gantry cranes are crane structures that have one or more hoists. They are also the best solution for moving materials outdoors such as crushers, ports, metal warehouses, and the best way for unloading cargo on trucks and ships, especially unloading and loading containers.
Semi-Gantry Cranes are mainly installed in outdoor areas that are special for unloading and loading cargoes. Semi-gantry cranes are structurally similar to overhead cranes with the only difference; they have two columns connected to a bridge and a head that travel along with them along the path. These types of cranes are in types: two bridges, single bridges, console and without the console, and etc.
By placing railings on both sides of the longitudinal path, gantry cranes can be installed and operated quickly. Therefore, one of their advantages is the possibility of moving and relocating from the current installation site to another location for use.
Arm gantry crane:
A cost-effective Jip crane or column crane integrates several displacement systems; sometimes using these types of cranes will be the best economic solution for you; you can also use these cranes in roofless spaces such as courtyards, on walls, sloping surfaces, or in buildings where other material handling equipment cannot be used.
The most common use of arm cranes is in workstations in factories. Machining, welding, packing, and assembly stations are examples of this, and arm cranes are used in areas that require light and simple load lifting and lowering.
The use of an arm crane is not recommended if you need a wide range of hooks or you often want to lift loads close to the maximum allowable.
The articulated type of arm crane is designed for better access to the corners.
Portal gantry crane:
This type of crane is very similar to the semi-gantry type, except that it has the ability to rotate. This type of crane is widely used in ports and customs.
These types of cranes are widely utilized in buildings and the transport of goods, especially within cities. They have the advantage of fast and unconditional handling and have different load handling capabilities.
These types of cranes are very similar to truck cranes; with the difference that they have a lower carrying capacity. These cranes are mostly applied for moving and carrying vehicles and light loads. The advantage of this type of cranes is the speed of work, ease of working with the device, low required space, and fast movement of the machine.
Chain wheel cranes:
In some cranes, due to the type of heavy operations they perform in the load or the working situation, it is not possible to utilize rubber, so more chains are used to distribute the pressure on the surface. One of the advantages of this type of cranes is the ability to move in the uneven ground, but the disadvantage of these devices is the possibility of less maneuverability and low speed in movement.
This device is mainly used in refineries, petrochemical plants and other large industrial projects. Their applications start from excavation and biomechanics in light types and continue to be used in refineries, power plants, bridges in heavy types.
These types of cranes are divided into two categories according to the type of operation:
Light chain cranes
Lift cranes have a lifting capacity (carrying) between 100 and 1200 tons. An important feature of cranes with low tonnage, low weight, the possibility of easier movement, high speed in installation, and in larger tonnages is the increase of lifting height up to 226 meters and access radius up to 165 meters.
Tower Cranes (Tower Cranes):
Tower crane is one of the most important human achievements that have different structures according to the type of user expectation and is implemented in the fields of tower construction, dam construction, silo construction, bridge construction, etc., which can be at different heights with different loads in different radius. It serves a variety of services, and according to the fact that it has very high maneuverability in the field of loading for various uses, it has attracted the attention of a large group of craftsmen, including in the field of tower construction.
A wall-mounted mobile crane is a type of crane that is used in terms of optimal use of the sides of the hall. The capacity of this crane is from 125 kg to 10 tons and its arm-length is 2 to 77 meters and it is designed as a single bridge and a pair of bridges. In wide halls, these types of cranes are the best option to equip a part of the width of the hall due to the removal of one side column independently or auxiliary and are more economical.
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