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Weihua crane, OVERHEAD crane development history
and crane classification and application
I. concept of crane
Crane (Crane) is a kind of lifting machinery, is a cycle, intermittent movement of machinery.A working cycle includes lifting the object from the fetching ground, moving horizontally to the designated place to lower the object, and then moving in reverse to return the object to its original position for the next cycle.
A multi - action lifting machine used to lift and lift heavy objects vertically and horizontally within a certain range.Also known as the crane.Belongs to the material handling machinery.The working characteristic of the crane is to do intermittent movement, that is to say, the corresponding mechanism of taking material, moving and unloading in a working cycle works alternately.
Generally, hoisting machinery is composed of lifting mechanism (to move objects up and down), operating mechanism (to move lifting machinery), amplitude changing mechanism and rotary mechanism (to move objects horizontally), plus metal mechanism, power plant, control and necessary auxiliary devices.
Two, the type of crane
Lifting machinery used in bridge construction projects, according to its different structure and performance, generally can be divided into light and small lifting equipment, bridge type lifting machinery and boom type crane three categories.Light and small lifting equipment such as: jack, hoist, hoist, etc.Bridge type of lifting machinery such as: bridge crane, gantry crane, etc.Gantry crane types such as double beam gantry crane, single beam gantry crane, etc.
Three, the prototype of the crane
The orange used for irrigating farmland in ancient China was the prototype of boom crane.In the 14th century, there appeared in Western Europe the rotary jib crane driven by human and animal power.In the early 19th century, bridge cranes appeared.Important wear parts of the crane, such as shafts, gears and spars, began to be made of metal materials, and began to use hydraulic drive.In the late 19th century, steam-driven cranes gradually replaced hydraulic ones.Since the 1920s, due to the rapid development of electric industry and internal combustion engine industry, various cranes with motor or internal combustion engine as the power device were basically formed.
Cranes mainly include: lifting mechanism, operating mechanism, amplitude mechanism, rotary mechanism and metal structure.Hoisting mechanism is the basic working mechanism of the crane, mostly composed of the hoisting system and winch, but also through the hydraulic system lifting heavy objects.The operating mechanism is used to move the weight vertically and horizontally or adjust the working position of the crane. It is generally composed of motor, reducer, brake and wheel.The amplitude variation mechanism is only equipped on the jib crane. The amplitude decreases when the boom is lifted up and increases when it is bent down. There are two kinds of amplitude variation, namely, balanced amplitude variation and non-balanced amplitude variation.The slewing mechanism is composed of a driving device and a slewing support device for slewing the arm frame.Metal structure is the skeleton of the crane, the main bearing parts such as bridge frame, arm frame and door frame can be box structure or truss structure, can also be web structure, some can be used as supporting beam profile
Iv. Cranes are classified according to different structures:
Girder crane can be used in rectangular site and above the operation, mostly used for workshop, warehouse, open storage yard and other goods loading and unloading, there are girder crane, bridge crane, gantry crane, cable crane, carrier bridge and so on.
Beam crane mainly includes single-beam bridge crane and double-beam bridge crane, single-beam bridge crane bridge bridge bridge girder is mainly used i-beam or steel and steel plate combination section.Lifting trolley is usually hand-pulled hoist, electric hoist or hoist as lifting mechanism parts assembly.
According to the bridge support type and suspension type of two.The former bridge frame runs along the crane track on the truck girder;The bridge of the latter runs along the crane track suspended under the roof of the factory building.Single beam bridge crane split, electric two.Manual single-beam bridge crane each mechanism of the work speed is low, the lifting weight is small, but their own quality is small, easy to organize production, low cost, when used for no power after the transfer of small, the speed and productivity requirements are not high occasions.
The working speed and productivity of electric single-beam bridge crane are higher than that of manual crane, and the lifting weight is larger.Electric single-girder bridge crane is composed of bridge frame, trolley operating mechanism, electric hoist and electrical equipment.
(2) bridge crane is a bridge frame crane, also known as overhead crane, which is mounted on the elevated track.The bridge frame of the bridge crane runs longitudinally along the track laid on both sides of the viaduct, and the crane trolley runs laterally along the track laid on the bridge frame, forming a rectangular working range, so as to make full use of the space below the bridge frame to lift materials and not be hindered by ground equipment.
Bridge cranes are widely used in indoor and outdoor warehouses, factories, docks and open storage yards.Bridge cranes can be divided into three types: ordinary bridge cranes, simple girder bridge cranes and metallurgical bridge cranes.
Ordinary bridge crane is generally composed of lifting trolley, bridge running mechanism and bridge metal structure.Lifting trolley is composed of lifting mechanism, trolley running mechanism and trolley frame.
Lifting mechanism includes motor, brake, reducer, drum and pulley block.Motor through the reducer, drive the drum rotation, so that the wire rope around the drum or down from the drum, to lift the weight.Trolley frame is the support and installation of lifting mechanism and trolley running mechanism and other parts of the rack, usually for the welding structure.
Cantilever crane (slewing crane) has three forms: pillar crane, wall crane and balance crane.
Column cantilever crane is cantilever can be fixed on the base of the fixed column rotation, or cantilever and rotating column is just connected, in the base of the support with respect to the vertical Central Line rotation of the cantilever and cantilever composed of a cantilever crane.It is suitable for the lifting weight is not big, the operation service scope is circular or the fan-shaped occasion.Generally used for machine tools and other workpiece loading and handling.
(2) wall crane is fixed on the wall of the cantilever crane, or cantilever crane can be along the wall or other supporting structures on the elevated track running.
The use of wall crane is the workshop or warehouse with large span and high building height.Wall crane is usually used in conjunction with the beam or bridge crane above. It serves as a rectangular space near the wall and is responsible for lifting small and light objects, while the large ones are undertaken by the beam or bridge crane.
(3) balance crane commonly known as balance crane, it is the use of four-link mechanism principle to make the load and balance the weight to form a balance system, can use a variety of lifting tools flexible and easy to lift the load in three-dimensional space.
The metal structure of bridge is composed of main beam and end beam, which can be divided into two categories: single main beam bridge and double beam bridge.A single girder bridge is composed of a single girder and end girder on both sides of the span, and a double girder bridge is composed of two main girders and end girders.
The main beam is rigidly connected to the end beam, and the end beam is equipped with wheels at both ends to support the bridge to run on the elevated frame.The main beam is welded with rails for crane operation.The structure types of bridge girder are more typical: box structure, four truss structure and hollow truss structure.
Box structure can be divided into the right track box double beam, off-track box double beam, off-track box single girder, etc.The right track box double beam is a kind of basic form which is widely used. The main beam is composed of the upper and lower flange plates and the vertical webs on both sides. The trolley rail is arranged on the Central Line of the upper flange plate.
Partial rail box double beam and rail box single girder cross section are ranged from upper and lower flange plate and the thickness of the deputy of web, rail car is decorated in the main web above, the casing short stiffening plate could save, in which partial rail box single main box girder is composed of a wide flange instead of two main girder, the weight is small, but made more complex.The four-truss structure is composed of four planar trusses to form a closed spatial structure. The upper horizontal truss surface is generally paved with walking boards, which have light deadweight and high stiffness. However, compared with other structures, the truss structure has a large external size, more complex manufacturing, lower fatigue strength and less production.
Vierendeel truss structure similar to partial rail box girders, is composed of four pieces of steel structure of a closed, in addition to the main web for solid abdomen i-section girder, the other three piece of sheet metal in accordance with the design requirements of cutting into many window, form a vierendeel truss without diagonal, in the upper and lower levels of truss surface covered by bedplate, crane running mechanism and electrical equipment installed inside the bridge, weight is lighter, the overall stiffness is large, it is more widely used in China a type.
Ordinary bridge crane is mainly driven by electricity, generally in the driver's indoor control, also has a handle control, and remote control.Weihua crane overhead crane, lifting weight up to 800 tons, span up to 70 meters.
Weihua crane,China national nuclear industry 70m span crane
Weihua crane,China one 800t bridge crane
Simple beam bridge crane is also called beam crane, its structure is similar to the ordinary bridge crane, lifting weight, span and working speed are small.