The boom-type tower crane (ie, the tilt-arm tower crane) is the earliest type of tower crane in history, and it has experienced a glorious history. From industrial buildings to civil buildings, from shipyards to port terminals, from steel structures to power station construction, boom-type tower cranes have played a huge role. Recalling the development of the boom-type tower crane is not only limited by the industrial level of a country, but also related to the economic development, culture and overall science and technology level of a country. After the Second World War, the post-war reconstruction led to the development of the tower crane. At this time, the height of the building was not high, and the boom-type tower cranes with the orbital and lower turns occupied a dominant position. In the 1950s, with the increase in high-rise buildings, the upper-swing self-elevating boom tower crane appeared. In the 1960s, the market share of boom-type tower cranes accounted for nearly 70% of large and medium-sized tower cranes. However, since the 1970s, the trolley turret has replaced the status of the boom-type tower crane.
In order to adapt to the needs of the market, the tower crane is required to have greater flexibility. Otto Kaiser proposed an unusual tower crane concept in the 1960s - HBK series folding boom tower crane , the mixture of the car luffing/boom luffing can be realized, which greatly improves the utilization rate of the equipment, and makes the tower machine design a solid and reliable step for the humanized design. The advantage is that when the tower crane is in the position of the trolley luffing arm, its working range is the largest; when the boom is raised, the boom can be converted into a few minutes without additional tower section. Increasing the height of the tower greatly expands the function and working range of the equipment, and is suitable for the construction of buildings such as cooling towers, TV towers and skyscrapers. The emergence of the bent boom tower crane makes the boundaries of the trolley luffing type and the boom luffing tower machine no longer clear, but its manufacturing cost is higher than that of the ordinary tower crane.
With the development of the economy, the dense building complex has limited the working space of the tower crane. Based on the development of high-rise buildings, the newly established licensing system for airspace rights and disputes arising from the occupation of neighboring territories have forced people to change existing traditional concepts, changing from small car to jib pitch, creating favorable space for tower crane operations. It has promoted the transformation and development of various types of boom tower cranes. The tower crane manufacturers all over the world have considered these factors in design and developed corresponding improved tower cranes. For the boom tower crane, when the boom is swept, this will generate additional static load torque. It is obviously very important to find a way to balance this torque and greatly increase the crane's lifting capacity. The mechanical solution is to move the counterweight and adapt it to the weight required for the boom to pitch. There are three methods to be adopted: 1 method of moving the weight of the wire rope; 2, using the action of the connecting rod to move the weight; 3 using the hanging weight and the boom linkage to achieve the purpose of moving the weight.
At present, many countries expressly stipulate in the building regulations that the lifting operation cannot exceed the construction work area, that is, the boom cannot exceed the building fence, and the boom tower crane can avoid the interference of multiple tower crane operations and the balance in the non-working state. The performance is superior to the horizontal arm tower crane, so the application of the boom tower crane is more common in the foreign construction industry. The boom tower crane has not been widely used in the domestic construction industry. The reason is that the boom tower crane has higher sales price than the horizontal arm tower crane with the same tonnage and the same lifting torque; the boom tower crane is lifting the heavy object. The time-varying speed is slower than that of the horizontal arm tower machine, and the working efficiency is relatively low. However, the super-high-rise steel structure project has a small footprint, and the steel structural members are heavy, most of which are 10 to 40 tons. The horizontal arm tower crane is difficult to meet the lifting weight and lifting torque, especially in this project. In order to improve the working efficiency, multiple tower cranes can be operated at the same time. The boom-type tower crane can avoid the interference between the tower cranes and meet the requirements of large lifting capacity. From the development trend of the construction industry, the city is getting more and more crowded. Only the boom-type tower crane can meet the construction requirements in the crowded city, and the application of the boom-type tower crane will be more and more.
At present, there are fewer manufacturers of booming tower cranes in China. There are only a few companies such as Shenyang Sanyo Construction Machinery, Sichuan Construction Machinery, and Fushun Yongmao. The weight of the boom tower crane is 4~24t, and the sales target is mainly for export. In these several hotels, the technical level and product quality of Shenyang Sanyo Construction Machinery 24t boom tower crane reached the same level in foreign countries. There are many manufacturers of booming tower cranes in foreign countries. The series of them are 4~80t boom tower cranes, especially the technical performance of WOLF company. The large tonnage boom tower machine produced by FAVCO is in cost performance and internal climbing technology. Dominant, sales are better. FAVCO's M440D, M900D, M1280D, etc. are used in projects such as Beijing, Shanghai, Guangzhou, and Shenzhen.