About the development process of tower cranes in China
In the early 1950s, China's tower cranes started from imitation. In 1954, it imitated the East German Architect I tower crane; in the 1960s, it designed and manufactured 25tm, 40tm, and 60tm models, mostly boom-type; in the 1970s, with the increase in high-rise buildings, new requirements were put forward for construction machinery, so 160tm attached, 45tm internal climbing, 120tm self-elevating tower cranes came out one after another; since the 1980s, China's tower crane industry has developed rapidly, especially in recent years, the sales of tower cranes have continued to rise. In 2001, the industry statistics sales volume was 9738 units, and in 2002, it became the first country in the world to produce more than 10,000 tower cranes per year. In 2004, due to the macro-control and structural adjustment of the crane industry, the production and sales of tower cranes fell back. In 2005 and 2006, driven by the rapid economic growth, the production and sales of tower cranes in China resumed rapid growth, and the sales in 2006 exceeded 20,000 units.
The production and application of tower cranes in China has a history of more than 40 years, and has gone through a process from surveying and imitation to self-design and manufacturing.
In the 1950s, in order to meet the needs of national economic construction, China introduced tower cranes from the former Soviet Union and some Eastern European countries and imitated them. In 1954, the prototype designed by the Democratic Republic of Germany was imitated and the first TQ2-6 tower crane in China was successfully trial-produced in Fushun. Subsequently, 15t and 25t tower cranes were developed based on the prototype of the former Soviet Union. During this period, the number of tower cranes produced and used in China was relatively small.
In the 1960s, due to the development of high-rise and super-high-rise buildings, internal climbing and external attachment tower cranes were widely used, and relatively advanced technologies were adopted in the working mechanism, such as DC motor speed regulation, thyristor speed regulation, eddy current brake, and installation of hydraulic couplings in the slewing and running mechanisms. During this period, China began to enter the stage of self-design and manufacturing of tower cranes. In 1961, the Hongqi-11 tower crane was first successfully trial-produced in Beijing, which was also the earliest tower crane designed by China. Subsequently, China designed and manufactured the TQ-6 tower crane. By 1965, there were more than 10 manufacturers in the country, producing more than 360 tower cranes. These tower cranes are all down-turning boom type, which can be towed as a whole and can meet the needs of civil construction below six floors.
In the 1970s, tower cranes served a wider range of objects. The amplitude, lifting weight and lifting height of tower cranes have been significantly improved. In order to meet the requirements of all aspects of the market, tower cranes have developed in the direction of one machine for multiple uses. China's tower cranes have entered a new stage of technological improvement and increased variety. In 1972, China's first down-slewing light tire-type rail dual-purpose crane was launched. In the same year, for the construction of the Beijing Hotel, China designed and manufactured the QT-10 self-erecting tower crane, which has a lifting torque of 1600kN·m. During this period, the company also developed ZT 100, ZT 120, ZT 280 and other trolley-type self-erecting tower cranes, QT-20 trolley-type internal climbing tower cranes, QTL 16, TQ 40, TQ 45, TD 25, QTG 40, QTG 60 down-slewing jib self-erecting quick-installation tower cranes, etc., with an annual output of more than 900 units, marking a new stage for China's tower crane industry.
In the 1980s, many new tower crane products appeared in China, including self-erecting tower cranes such as QTZ 100 and QZT 120, and down-slewing fast-installing tower cranes such as QT 60, QTK 60 and QT 25HK. The performance of these products is close to the level of foreign products in the 1970s, and the highest annual output during this period reached 1,400 units. At the same time, with the reform and opening up and the increase in international technical exchanges, in order to meet the needs of construction, some tower cranes were also introduced from abroad, including products from companies such as Liebherr in the Federal Republic of Germany, Potain in France, and Edilmac in Italy. As these tower cranes have good manufacturing quality and advanced technical performance, they have greatly promoted the progress of the design and manufacturing technology of Chinese tower crane products.
After the 1990s, China's tower crane industry entered a new period of prosperity with the increase of construction tasks across the country, and the annual output has soared year by year, and some products have been exported abroad. The total number of tower cranes in China has also increased from a few dozen in the 1950s to about 60,000 in 2000. There are now more than 300 manufacturers in China, 241 of which have obtained production licenses; the annual output is about 9,000 units; more than a dozen companies have an output value of over 100 million yuan and profits and taxes of over 10 million yuan. Since 1992, the annual export volume of tower cranes has been greater than the import volume, the annual export amount has been greater than the import amount, and the annual trade surplus has reached more than 8 million US dollars. On the premise of basically meeting the needs of national economic development, it can be exported to earn foreign exchange. So far, no matter from the perspective of production scale, application scope and total number of tower cranes, China can be called a tower crane power. However, since China has joined the WTO, the current situation of China's tower crane production is not optimistic after a calm analysis. There are the following problems:
Irrational product structure and similar varieties and models
Technical regulations restrict product development. Due to the product model classification standards formulated by China in the 1980s, the main parameters such as lifting speed, rotation speed, amplitude change speed, travel speed, lifting speed, lifting weight, lifting torque, and geometric dimensions such as the leg span and tail rotation radius of the lower slewing tower crane are strictly regulated, which seriously restricts the technological progress of tower cranes. The unstable user base also restricts technological progress. In China, a large number of small and medium-sized construction companies are not well-funded and lack long-term planning. They use second-hand goods eliminated by large companies and old tower cranes that have exceeded their service life. Therefore, the fast-erecting tower cranes that are widely used in developed countries with convenient transportation, rapid erection, and safe use are neglected in China. At the same time, the lack of innovation ability of enterprises has also affected product development. Many newly established enterprises have weak research and development capabilities. Most products are jointly developed with colleges and universities and scientific research institutions. The same product can be produced by several or even dozens of companies, and the company's own characteristics have not been formed.
Manufacturing technology is not adapted and scale industry has not been formed.
In the past 20 years, although the level of China's tower crane manufacturing industry has improved, it is still backward compared with the advanced manufacturing technology of some other industries, and there is a big gap compared with our similar engineering machinery backbone enterprises. Many manufacturers have low production efficiency, high environmental pollution, and it is difficult to guarantee the quality of welding and the appearance of finished products. Only a very small number of enterprises have processed the base before painting. The management model and production method of most enterprises are still the traditional multi-level progressive static model. Some are still small and comprehensive or large and comprehensive. The degree of specialization, process equipment and management level are low. It is difficult to adapt to the fierce competition of multi-variety mass production and commodity economy, and it is difficult to form their own national scale industry.
Because the industry statistics only count the sales of 20 to 30 production enterprises, the sales of the entire industry must be far more than the statistical figures. There is no doubt that China has become a major producer of civil tower cranes in the world and one of the main demand markets for tower cranes in the world. According to preliminary statistics, there are more than 400 tower crane manufacturers in China that have obtained production licenses, while there were less than 100 in the 1980s.