The development of scrapers has a history of hundreds of years. In the 18th century, horse-drawn scrapers appeared. Their buckets were placed on the ground and pulled by horses. The transport distance was about 15~50m. In 1883, wheeled all-metal scrapers were manufactured. In 1910, the United States manufactured special scrapers pulled by tractors. The former Soviet Union mass-produced tire-towed scrapers after the 1920s.
In 1938, the United States manufactured self-propelled scrapers. In 1949, twin-engine scrapers were manufactured. In the 1960s, chain-loaded scrapers and the world's largest scraper (with a bucket capacity of 200m³) were manufactured.
Compared with the first generation of self-propelled scrapers, the product grade of the CL7 self-propelled scraper has undergone a qualitative change, creating a new era for scrapers in my country.
The glorious history of scrapers in China
China began the research and development of scrapers in the 1960s. In April 1961, Zhengzhou Engineering Machinery Manufacturing Plant/Engineering Machinery Research Institute of the First Ministry of Machinery Industry and Xiamen Engineering Machinery Plant (the predecessors of Yutong Heavy Industry, Tianjin Engineering Machinery Research Institute and XCMG Group, respectively) established a joint design team to develop my country's first generation of self-propelled shovel loaders with reference to foreign prototypes. The design was completed in August of the same year. On December 22, 1962, China's first self-propelled shovel loader prototype C-6106 was born in Zhengzhou Engineering Machinery Manufacturing Plant.
The shovel loader can have both shoveling and transportation functions on its own. Especially when the transportation distance is between 200 to 300 meters and 1 to 2 kilometers, its operating economic efficiency is significantly better than the construction efficiency of other mechanical combinations. In view of this, in the 1960s and 1970s, the research and development of shovel loaders received attention from relevant national departments [1]. In August 1963, according to the "1964 New Product Key Control Project" plan of the State Science and Technology Commission, Zhengzhou Engineering Machinery Manufacturing Plant and the Engineering Machinery Research Institute of the First Ministry of Machinery Industry established a joint design team to develop and design the CL7 self-propelled shovel loader. The CL7 self-propelled scraper, which was trial-produced in 1972, adopts hydraulic mechanical transmission, and the movements of its bucket parts are also changed to hydraulic cylinder control. Compared with the first generation of self-propelled scrapers, the product grade of the CL7 self-propelled scraper has undergone a qualitative change, creating the first new era of scrapers in my country. The machine represented the latest level of China's electromechanical products at that time. It was sent to Cologne, Germany to participate in the international exhibition in June 1975; and won the National Science and Technology Conference Award in 1978. In October 1978, according to the requirements of the First Ministry of Machinery, two CL7 self-propelled scrapers were used in the Golmud to Xidatan section of the planned Qinghai-Tibet Railway. The first industrial test of my country's construction machinery on the plateau was carried out.
Today, decades later, the scraper that once carried the mission and honor is struggling. Although the scraper is quite economical in scraping and transporting operations, it has been replaced by the combination of excavators or loaders and dump trucks. According to statistics, in the United States, the earthwork volume completed by scrapers accounts for 40% of the total earthwork engineering.
