Classification and relevant parameters of the hott

2022-08-14
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Cranes can be divided into truck cranes, tire cranes, cross-country tire cranes, all terrain cranes and special cranes according to different installation methods

1. Truck crane

the crane is installed on the chassis of general-purpose or special-purpose vehicles, and the low plate performance is equivalent to the truck with the same total weight of the whole vehicle, which meets the technical requirements of road vehicles, so it can pass unimpeded on all kinds of roads. This kind of crane is generally equipped with two control rooms for getting on and off, and the outriggers must be extended to maintain stability during operation. The lifting capacity can range from 8 tons to 1000 tons, and the number of axles of the chassis can range from 2 to 10. It is the crane type with the largest output and the most widely used

2. Tire crane

a crane whose lifting part is installed on a special pneumatic tire chassis. One engine is used for boarding and alighting. The driving speed is generally no more than 30km/h, and the vehicle width is relatively wide. Therefore, it is not suitable to drive long distances on the highway. It has the function of lifting and traveling without outriggers, and is suitable for lifting operations in freight yards, wharves, construction sites and other places with limited moving distance

3. The off-road tire crane

is a crane developed in the 1970s. Its lifting function is similar to that of the tire crane, and it can also be used to lift and drive without outriggers. The difference is the structural form of the chassis and the improvement of driving performance brought by the unique chassis structure. The engine of this crane is installed on the chassis, which has two axles and four large-diameter cross-country tires. The four wheels are driving wheels and steering wheels. When transferring stations on muddy and uneven construction sites, the four wheels transmit power, that is, four-wheel drive, to improve the ability to pass through muddy and uneven roads. When driving at a faster speed on a flat road, only two wheels of the front axle or the rear axle are used to drive to reduce energy consumption. In the accompanying documents of the crane, use 4 × 4 means four-wheel drive, 4 × 2 means that two of the four axles are driving wheels. This model is suitable for working in narrow places. It can realize continuous stepless speed change, and the engine will not shut down in the case of sudden changes in road resistance, which greatly facilitates the driver's operation. It can be seen that the off-road tire crane is a powerful and flexible tire crane with expanded performance

4. All terrain crane

is a high-performance product with the characteristics of both truck crane and rough terrain crane. It can not only transfer quickly and travel for a long distance like a truck crane, but also meet the requirements of working on narrow and rugged sites for 2 hours of continuous, safe and stable operation or muddy sites compared with virgin materials, that is, fast driving speed, multi axle drive, all wheel steering, three steering modes, large ground clearance, high climbing ability, and no outrigger lifting and other functions. It is a very promising product to strictly prevent water contamination. However, the price is high and the requirements for the use and maintenance level are high

5. Special crane

a special crane developed to complete a specific task. For example: crane wheel rescue vehicles installed on off-road vehicles or armored vehicles for the implementation of tactical and technical support for mechanized forces; Road obstacle removal vehicles used to deal with traffic accidents belong to this category

crane work type: refers to the parameters of crane work busy degree and load change degree

the degree of busy and idle work, for cranes, refers to the ratio of the actual operating hours of cranes to the total hours in a year; For an organization, it refers to the ratio of the operating hours of an organization to the total hours in a year. In a working cycle of the crane, the percentage of the operating time of the mechanism is called the load duration of the mechanism, which is expressed in JC

load change degree. In actual operation, the load lifted by the crane designed according to the rated lifting capacity is often less than the rated lifting capacity. The variation degree of this load is expressed by the lifting capacity utilization factor K. K= the average value of the actual lifting capacity of the crane in the whole year/the rated lifting capacity of the crane

according to the busy degree and load change degree of the crane, the work type of the crane is usually divided into four levels: light level, medium level, heavy level and extra heavy level

the working type and lifting capacity of crane are two different concepts. Large lifting capacity is not necessarily heavy class, small lifting capacity is not necessarily light class. For example, the crane used in the hydropower station has a lifting capacity of hundreds of tons, but there are few opportunities to use it. It is only used when installing and repairing units, and it stops there for the rest of the time. Therefore, although the lifting capacity is large, it is still of light class. Another example is the gantry crane used in the station freight yard. Although the lifting capacity is small, it is very busy and belongs to the heavy work type

the working type of crane is closely related to its safety performance. For cranes with the same lifting capacity, span and lifting height, if the work type is different, the safety factor adopted in the design and manufacture is different, that is, the model, size and specification of parts are different. For example, due to different types of work and different safety factors (small safety factor of light class and large safety factor of heavy class), the selected models are different. As for the 10t bridge crane, the power of the lifting motor for the intermediate working type (jc=25%) is n=16kw, while for the heavy working type (jc=40%), the power of the lifting motor is n=23.5kw

from the above situation, it can be seen that if the light-duty crane is used in the heavy-duty 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 of three 3D printed conduit curves, including the bearing capacity of the crane structure, the lifting capacity of the boom and the anti overturning stability of the whole machine

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