A crane is a machine that hangs heavy objects with hooks or other fetching devices and performs cyclic operations such as lifting and moving in the space. There are many classifications of cranes, this article focuses on introducing its specific classification.
Lifting machinery used in bridge construction projects can be generally divided into light and small lifting equipment, bridge type lifting machinery and boom type cranes, and cable cranes according to their different structures and performances. Light and small lifting equipment such as: jacks, pneumatic hoist, electric hoist, balance hoist (also known as balance hoist), hoist and so on. Bridge type lifting machinery such as beam cranes, gantry cranes, etc. Boom type cranes such as fixed slewing cranes, tower cranes, truck cranes, tire cranes, crawler cranes, etc. Cable cranes such as lifts.
1. Divided by nature:
According to the lifting nature: mobile cranes, tower cranes, mast cranes.
According to the structure, the crane is mainly divided into light and small lifting equipment, bridge type (bridge type, gantry crane), boom type (self-propelled, tower type, gantry type, railway type, pontoon type, mast type crane), Cable style.
1. Light lifting equipment
The characteristics of light and small lifting equipment are light weight, compact structure, simple operation, and the projection of the working range is mainly dots and lines. Light and small lifting equipment generally has only one lifting mechanism, which can only make a single lifting movement of heavy objects. Those that fall into this category include: jacks, tackles, hand (gas, electric) hoists, winches, etc. Electric hoists are often equipped with running trolleys and metal frames to expand the scope of work.
<electric hoist>
CD1, MD1 series wire rope electric hoist is an improved product based on the original CD, MD type. It has the characteristics of compact structure, light weight, safety and reliability, high universality of parts, strong interchangeability, high lifting capacity and convenient maintenance. It is a light-weight lifting equipment that is widely used and popular.
There are two types of hoist: fixed type and trolley type. The fixed type is divided into four types of A1, A2, A3, and A4 according to the different positions of the fixed feet in the upper, lower, left, and right. It can be directly installed on the frame. The trolley type has a running function and can be installed on the track. CD1 type is single speed hoisting, MD1 is normal speed and slow speed hoisting.
2. Bridge crane
It can be operated in the rectangular field and over the sky. It is mostly used for the loading and unloading of items in workshops, warehouses, open yards, etc. There are beam cranes, bridge cranes, gantry cranes, cable cranes, carrier bridges, etc.
(1) Beam crane: The beam crane mainly includes a single beam bridge crane and a double beam bridge crane
The main beam of the single-girder bridge crane mostly adopts I-shaped steel or a combined section of steel and steel plate. Lifting trolleys are often assembled from hand hoist, electric hoist or using hoist as part of lifting mechanism.
According to the bridge mode, it is divided into two types: support type and suspension type. The former bridge runs along the crane track on the vehicle beam; the latter bridge runs along the crane track suspended under the factory frame. There are two types of single beam bridge cranes, manual and electric. The working speed of each mechanism of the manual single-beam bridge crane is low, and the lifting capacity is also small, but its own quality is small, which is easy to organize production, and the cost is low. Occasions. The manual single-beam bridge crane uses a manual monorail trolley as a running trolley, a hand hoist as a lifting mechanism, and the bridge frame is composed of a main beam and an end beam. The main beam is generally made of a single I-beam, and the end beams are welded with section steel or press-formed steel plates.
The working speed and productivity of the electric single-beam bridge crane are higher than that of the manual, and the lifting capacity is also larger. The electric single-beam bridge crane is composed of a bridge frame, a truck operating mechanism, an electric hoist and electrical equipment.
(2) Bridge crane:
Bridge crane is a bridge-type crane that the bridge runs on the elevated track, also known as overhead crane. The bridge frame of the bridge crane runs longitudinally along the rails laid on the elevated side of the two sides, and the lifting trolley runs laterally along the rails laid on the bridge, forming a rectangular working range, which can make full use of the space under the bridge to lift materials, without Obstructed by ground equipment.
The characteristic of the bridge crane is that it can realize the vertical lifting or horizontal movement of the heavy objects hanging on the hook or other fetching devices. Bridge cranes include: lifting mechanism, large and small truck operating mechanism. Relying on the cooperative action of these mechanisms, heavy objects can be lifted and carried in a certain cubic space. Bridge cranes, gantry cranes, loading and unloading bridges, metallurgical bridge cranes, cable cranes, etc. all belong to this category.
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 beam bridge cranes and metallurgical bridge cranes.
The ordinary bridge crane is generally composed of a lifting trolley, a bridge running mechanism, and a bridge metal structure. The lifting trolley is composed of three parts: a lifting mechanism, a trolley running mechanism and a trolley frame.
The lifting mechanism includes motor, brake, reducer, reel and pulley block. The motor drives the drum to rotate through the speed reducer, so that the steel wire rope is wound on the drum or lowered from the drum to lift the heavy object. The trolley frame is a frame that supports and installs components such as a lifting mechanism and a trolley running mechanism, and is usually a welded structure.
Bridge Gantry Crane Introduction
The gantry crane is a bridge-type crane in which the horizontal bridge is set on two legs to form the shape of a gantry. This crane runs on the ground track and is mainly used in open storage yards, docks, power stations, ports and railway cargo stations for handling and installation operations. The lifting mechanism, trolley running mechanism and bridge structure of the gantry crane are basically the same as the bridge crane. Due to the large span, most crane operating mechanisms use separate drive methods to prevent the crane from skewing and increasing resistance, or even an accident. The lifting trolley of the gantry crane runs on the bridge frame, and some of the lifting trolley is a jib crane. The legs on both sides of the bridge are generally rigid legs; when the span exceeds 30 meters, it is often a rigid leg on one side, and a flexible leg connected to the bridge through a ball hinge on the other side, making the portal a statically determinate system , This can avoid the additional stress caused by the lateral thrust under the external load, and can also compensate for the temperature deformation of the longitudinal direction of the bridge. The gantry crane has a large wind area. To prevent sliding or tipping under the action of strong winds, an anemometer and Crane rail clamp interlocked with running mechanism. The bridge frame can be cantilevered at both ends; it can also be cantilevered at one end or cantilevered at both ends to expand the working range. The semi-gantry crane bridge has legs at one end and no legs at the other end, and runs directly on the high platform. Gantry cranes are divided into 4 types.
①Ordinary gantry crane: This crane is the most versatile. It can handle various pieces and bulk materials, with a lifting capacity of less than 100 tons and a span of 4 to 35 meters. The working level of ordinary gantry crane with grab is higher.
② Gantry crane for hydropower station: mainly used for lifting and opening and closing the gate, and can also be installed. The lifting weight is 80-500 tons, the span is small, 8-16 meters; the lifting speed is low, 1-5 meters/minute. Although this kind of crane is not often lifted, but once it is used, it is very heavy, so it is necessary to appropriately increase the work level.
③Shipbuilding gantry crane: used for assembling the hull of the berth, there are often two lifting trolleys: one has two main hooks, which runs on the rail of the flange on the bridge; the other has a main hook and a sub hook. The lower flange of the bridge runs on the track for turning and hoisting large hull sections. The lifting weight is generally 100 to 1500 tons; the span is up to 185 meters; the lifting speed is 2 to 15 meters/minute, and there is also a micro-motion speed of 0.1 to 0.5 meters/minute.
④Container gantry crane: used in container terminal. After the tow truck transports the containers unloaded from the ship to the yard or the rear, the container gantry crane stacks the containers or directly loads them away, which can speed up the turnover of the container carrier bridge or other cranes. The storage yard for stacking containers with 3 to 4 stories high and 6 rows wide is generally tire type, but also rail type. Compared with the container straddle truck, the container gantry crane has a larger span and height on both sides of the gantry. In order to meet the transportation needs of ports and terminals, this crane has a higher working level. The lifting speed is 8～10m/min; the span is determined according to the number of container rows that need to be crossed, and the maximum is about 60m, which corresponds to the 20ft, 30ft, and 40ft long containers. The lifting weights are about 20 tons and 25 tons, respectively. And 30 tons.
④Carrier bridge
A bridge type crane developed by the gantry crane increasing the span, also known as the loading and unloading bridge. Used in open storage areas, ports and railway cargo stations. The structure of a common carrier bridge is similar to that of a large gantry crane. The characteristics are: ① The objects to be transported are mainly large quantities of bulk materials; ② The span is large, generally more than 30 meters, and some are up to 170 meters; ③ Frequent operations and high productivity, generally 500 ~ 1500 tons / hour, high working speed , The lifting speed is 60-70 meters/minute, the running speed of the trolley is 100-350 meters/minute, and the working level is higher; ④ The operating mechanism of the carrying bridge is only used to adjust the working position and is a non-working mechanism. When the span is large, the bridge of the carrying bridge is supported on a rigid leg and a flexible leg. The bridge and the two legs can be connected by bolts; the connection with the flexible legs can also be through ball joints or column hinges, so that the flexible legs can have a certain range of deflection relative to the bridge. The bridge consists of truss beams, and the lifting trolley runs on its upper chord or lower chord track. Some trolleys have slewing jib, which is equivalent to a jib crane running on the bridge.
The container carrier bridge running on the shore of the port is a large crane with a special structure, which is dedicated to the container loading and unloading of ships. Both sides are generally rigid legs, forming a strong portal, the bridge is supported on the upper frame connected with the portal. A trolley with a container spreader (see straddle carrier) runs on the bridge. Long cantilevers reaching the sea are usually pitchable. When not in operation, the cantilever can be hoisted at an elevation angle of 80° to 85°, allowing the carrying bridge to pass the highest point on the ship. The cantilever is flat when working. Some cantilevers are fixed.
(3) Gantry cranes are generally classified according to the gantry structure form, main beam form, and spreader form. Generally used in ports.
Second, according to the door frame structure
(A) Full portal crane: The main beam has no overhang, and the trolley is carried out within the main span.
(B) Half gantry crane: The height of the outrigger is different, which can be determined according to the civil requirements of the site.
(C) Double cantilever gantry crane: the most common form of structure, the stress of the structure and the effective use of the site area are reasonable.
(D) Single cantilever gantry crane: This type of structure is often selected because of site constraints.
According to the main beam structure
(A) Single main beam gantry crane
The single main beam cantilever gantry crane has a simple structure, is easy to manufacture and install, and has low quality. The main beam is mostly a deviated box frame structure. Compared with the double main beam gantry crane, the overall rigidity is weaker. Therefore, this form can be adopted when the lifting weight Q≤50t and the span S≤35m. The legs of the single main portal beam crane have two types: L-shaped and C-shaped. The L-shaped crane is easy to manufacture and install, has good stress conditions, and has a low quality. However, the space for lifting cargo through the legs is relatively small. The C-shaped feet are made inclined or bent, the purpose is to have a larger lateral space, so that the goods can smoothly pass through the feet.
(b) Double beam bridge crane
The double-beam bridge crane is composed of straight rails, crane main beams, lifting trolleys, power transmission systems and electrical control systems, and is particularly suitable for large-scale suspension and large-lift flat-range material transportation.
The double beam bridge crane has strong bearing capacity, large span, good overall stability, and many varieties, but its own quality is larger than that of a single main beam gantry crane of the same weight, and the cost is also higher. According to the different main beam structure, it can be divided into box beam and truss. The box-shaped structure is generally used.
Gantry crane, gantry crane
3. Boom crane
The characteristics of the jib crane are basically the same as the bridge crane. It can be operated in a circular field and over the sky. It is mostly used for outdoor loading and unloading and installation. There are portal cranes, floating cranes, mast cranes, wall cranes and deck cranes.
The jib crane includes: lifting mechanism, luffing mechanism and rotating mechanism. Relying on the cooperative action of these mechanisms, heavy objects can be lifted and transported in a certain cylindrical space. The jib cranes are mostly installed on vehicles or other forms of transportation (moving) tools, which constitute the operating jib cranes. Such as truck cranes, tire cranes, tower cranes, gantry cranes, floating cranes, railway cranes, etc.
1) Cantilever crane
There are three types of upright, wall-mounted and balanced cranes.
①The column type cantilever crane is a cantilever crane composed of a vertical column and a cantilever that can rotate around a fixed column fixed on the base, or the cantilever and the rotating column are just connected and rotate relative to the vertical center line together in the base support. It is suitable for occasions where the lifting capacity is not large and the operation service range is round or sector. It is generally used for clamping and handling of workpieces such as machine tools.
Column type cantilever cranes mostly use ring chain electric hoist as lifting mechanism and running mechanism, and less use wire rope electric hoist and hand hoist. Rotation and horizontal movement operations are mostly manual, only when the lifting weight is large
Only when electric is used.
②The wall crane is a cantilever crane fixed on the wall, or a cantilever crane that can run along the elevated track on the wall or other supporting structure.
The wall crane is used in a workshop or warehouse with a large span and a large building height. It is most suitable when the lifting operation near the wall is more frequent. Wall cranes are mostly used in conjunction with the beam or bridge cranes above, serving a rectangular space near the wall, responsible for lifting light and small objects, and the large parts are borne by the beam or bridge cranes.
③ Balance crane is commonly known as balance crane. It uses the principle of four-bar linkage to make the load and balance weight form a balance system. It can use a variety of spreaders to flexibly and easily lift the load in three-dimensional space. The balance crane is light and flexible, and is an ideal lifting equipment for lifting small items. It is widely used in the loading and unloading of machine tools on the factory floor, the parts in the process, automatic lines, production lines, sand box lifting, parts assembly, and Stations, docks, warehouses and other occasions
(2) Tower crane
Generally used on construction sites to lift materials.
(3) Portal crane
(4) Mobile crane
Mobile cranes can be generally divided into truck cranes (car cranes), tire cranes (tire cranes), off-road tire cranes, all-terrain cranes, crawler cranes (crawler cranes), and special cranes.
The English name of Truck Crane is Truck Crane, which is denoted by QY in China, such as QY20/20t truck crane (car crane). A crane that installs a crane platform on the chassis of a general or special truck. Generally, it is some small tonnage cranes, which is the most seen in China at present.
The English name of Truck Crane is Truck Crane, which is denoted by QY in China, such as QY20/20t truck crane (car crane). A crane that installs a crane platform on the chassis of a general or special truck. Generally, it is some small tonnage cranes, which is the most seen in China at present.
The English name of All Terrain Crane is All Terrain Crane, which is expressed in China by QAY, such as China United QAY500/500t all-terrain crane. The main features of the all-terrain crane are: its driving cab is separated from the lifting control room, compact structure, light weight, small size, and good driving performance; the suspension method of the chassis is oil and gas suspension, and the shock absorption effect is obvious; according to The road surface is automatically leveled to improve the climbing ability; it can achieve all-wheel steering, full-axle drive, small turning radius, crab-shaped walking, and a wider range of use; the height of the frame can be raised or lowered as needed , To improve driving performance and passing ability; the outrigger span is large, and the operation stability is good; it can be operated in 360 degrees in all directions without the restriction of the front area; the outrigger must be used during work, and it cannot be driven under load.
Rough Terrain Crane, which can produce tire cranes (tire cranes) in China.
Crawler Crane.
The following is a brief introduction of various mobile cranes:
1. Truck crane
Truck crane: Truck crane English name Truck Crane, domestically expressed as QY, such as QY20/20t truck crane (car crane). The crane is installed on the chassis of a general-purpose or special-purpose vehicle. The chassis performance is equal to that of a truck with the same total vehicle weight, which meets the technical requirements of road vehicles, so it can pass on all kinds of highways without hindrance. This type of crane is generally equipped with two operating rooms for getting on and off the vehicle, and the outriggers must be extended to maintain stability during operation. The lifting capacity ranges from 8 tons to 1000 tons, and the number of axles of the chassis can be from 2 to 10. It is the largest and most widely used crane type.
2. Tire crane
Rough Terrain Crane (tire crane), there is no tire crane (tire crane) in China. Japan's TR200M/20t tire crane, the US Grove RT980/80ust tire crane. The crane is mounted on a special pneumatic tire chassis. The same engine is used to get on and off the vehicle, and the driving speed generally does not exceed 30KM/H, and the width of the vehicle is also wide, so it is not suitable to drive long distances on the highway. It has the function of lifting and traveling without supporting legs, and is suitable for lifting operations in places with limited moving distances such as freight yards, docks, and construction sites. Due to the fact that there are some accidents often caused by the use of outrigger cranes and crane cranes, major domestic crane companies have gradually canceled crane cranes. The main feature of the tire crane is that its driving cab and lifting control room are combined into one, which is evolved from a crawler crane (crawler crane), and the crawler and walking bracket parts of the walking mechanism are turned into a chassis with tires to overcome In addition, the crawler crane (crawler crane) has the disadvantage of damage to the road surface. The driving speed is faster than the crawler crane (crawler crane); the operation is stable, the lifting capacity is large, and it can be lifted and walked within a specific range, but the road must be smooth It is firm, the tire pressure meets the requirements, and it must not exceed 50 cm when it is lifted off the ground; walking with a long distance under load is prohibited. In order to ensure the safety of operations, at present, lifting operations without hitting outriggers are basically prohibited in China.
3. Off-road tire crane
It is a crane developed in the 1970s. Its lifting function is similar to that of a tire crane. It can also be used for lifting without legs and lifting weights. The difference is the structural form of the chassis and the improved driving performance brought about by the unique chassis structure. The engines of this crane are all mounted on the chassis, which has two axles and four large-diameter off-road tires. All four wheels are driving wheels and steering wheels. When transferring positions on the muddy construction site, all four wheels transmit power, that is, four-wheel drive, to improve the ability to pass through the muddy ground and uneven road surface. When driving on a flat road at a faster speed, only two wheels of the front axle or the rear axle are used to drive to reduce energy consumption. In the random file of the crane, 4×4 is used to indicate four-wheel drive, and 4×2 indicates that two of the four axles are driving wheels. This model is suitable for small field operations. Continuous stepless speed change can be realized, and the engine will not stop when the road resistance changes suddenly, thus greatly facilitating the driver's operation. The off-road tire crane is a powerful and flexible tire crane with extended performance.
4. All-ground type
It is also called all-terrain crane. The English name of all-terrain crane is All Terrain Crane, which is expressed in China by QAY, such as China United QAY500/500t all-terrain crane. It is a high-performance product with the characteristics of truck crane and off-road crane. It can not only transfer quickly and travel long distances like a truck crane, but also meet the requirements of working on small and rugged or muddy fields, that is, fast driving speed, multi-axle drive, all-wheel steering, three steering methods, off-ground The gap is large, the climbing ability is high, and it can walk in a crab shape, which is a very promising product. However, the price is higher, and the requirements for use and maintenance are higher.
5. Crawler crane
Crawler Crane (Crawler Crane) is generally expressed by QUY in China. However, the crane of Sany is in line with international standards, using the English naming rules, and its crawler crane is code-named SCC (SANY Crawler Crane). The main characteristics of the crawler crane are: its driving cab and lifting control room are combined into one, the grounding area is large, the average pressure on the ground is small, the stability is good, it can work on the soft and muddy ground; the traction coefficient is high, the climbing The slope is large, and it can be driven on rugged terrain; however, the crawler crane travels slowly, and the road surface is damaged during the driving process. Therefore, it needs to be transported by flatbed trailer during the transfer operation, and the mobility is poor.
6. Special crane
A special crane developed to complete a specific task. For example: the ambulances mounted on off-road vehicles or armored vehicles for the implementation of tactical technical support for mechanized forces; highway wreckers for handling traffic accidents, etc., all belong to this category.
The working type of the crane: refers to the parameters of the busyness of the crane and the degree of load change.
The degree of busyness of work, for cranes, refers to the ratio of the actual operating hours of the crane to the total hours within a year; for organizations, it refers to the hours of operation of an organization within a year Ratio to total hours. In a working cycle of the crane, the percentage of the operating time of the mechanism is called the load continuity rate of the mechanism, which is expressed in JC.
The degree of load change, the crane designed according to the rated lifting weight in actual operation, the load lifted by the crane is often less than the rated lifting weight. The degree of change of this load is expressed by the utilization factor k of the lifting weight. k = the average value of the actual lifting capacity of the crane throughout the year / the rated lifting capacity of the crane.
According to the crane's work busyness and load variation, the crane's work type is usually divided into four levels: light, intermediate, heavy and extra heavy.
The working type and lifting capacity of the crane are two different concepts. Large lifting capacity is not necessarily heavy, and small lifting capacity is not necessarily light. For example, the crane used in a hydropower station has a lifting capacity of hundreds of tons, but there are few opportunities for use. It is only used when installing and repairing the unit, and it is stopped there for the rest of the time, so although it has a large lifting capacity, it is still light. . Another example is the gantry crane used in the freight yard of the station. Although the lifting capacity is not large, the work is very busy and belongs to the heavy work type.
The working type of the crane is closely related to the safety performance. For cranes with the same lifting weight, span and lifting height, if the work types are different, the safety factor adopted during design and manufacturing is different, that is, the part models, sizes and specifications are different. For example, due to different working types and different safety factors of steel wire rope and brake (light safety factor is small, heavy safety factor is large), the selected models are different. Again like a 10t bridge crane, the power of the lifting motor is N=16KW for the intermediate working type (JC=25%), and N=23.5 for the lifting motor power of the heavy working type (JC=40%). KW.
It can be seen from the above situation that if a light-duty work type crane is used in a heavy-duty work type place, the crane will often fail, affecting safety production. Therefore, during the safety inspection, it should be noted that the working type of the crane must be consistent with the working conditions.
Crane characteristic curve: the envelope curve of three curves consists of the carrying capacity of the crane structure, the lifting capacity of the boom and the anti-overturning stability of the whole machine.
4. Cable type
The cable type mainly refers to a lifting crane commonly known as a lift, which is characterized in that a heavy object or a fetching device can only be raised and lowered along a guide rail. Although the elevator has only one lifting mechanism, there are many other attachments in the elevator, so it constitutes a separate category, which includes: elevators, freight elevators, ship lifts, etc. In addition, there are multiple classification methods for cranes. For example, according to the sorting device and use, there are hook crane, grab crane, electromagnetic crane, metallurgical crane, stacking crane, container crane and rescue crane, etc.; according to the transportation method, there are fixed crane and running crane , Self-propelled cranes, towing cranes, climbing cranes, portable cranes, truck-mounted cranes, etc.; classified by drive mode, with support cranes, suspended cranes, etc.; classified by use occasions, there are workshop cranes, machine room cranes, warehouse cranes , Storage yard crane, construction crane, engineering crane, port crane, shipyard crane, dam crest crane, shipboard crane, etc.
