A soil moving machinery that uses a scraper to level the ground. The scraper is installed between the front and rear axles of the machine and can be lifted, tilted, rotated, and extended. Flexible and accurate movements, easy operation, high precision in leveling the site, suitable for constructing roadbeds and pavements, building slopes, excavating side ditches, mixing road mixtures, clearing snow, pushing granular materials, and performing maintenance work on dirt and gravel roads.
There are two types of graders: dual axis and triple axis. The commonly used one is the triple axis. The rear axle is a dual axis four-wheel drive with a balancer to balance the force on each wheel. The front axle is a single axis dual wheel drive with a differential for easy steering. The three-axis grader travels smoothly and has good leveling operation effect. Even under unilateral load, it can maintain straight line travel and has high production efficiency. It is widely used in various civil engineering constructions.
The scraper of the grader is mounted under the rotating ring through two brackets, and the rotating ring can rotate to adjust the position of the scraper. The bracket of the rotating ring is triangular in shape, with its front end hinged at the front of the main frame, and the two corners of the rear end suspended in the middle of the main frame by lifting hydraulic cylinders. At the same time, it is hinged to the tilting hydraulic cylinder on the main frame, so that the scraper can be lifted, tilted or inclined to extend from one side of the longitudinal axis of the main frame to level the road slope. The scraper can also be adjusted in position to level the vertical slope. The scraper can be extended or equipped with a scraper blade using bolts, hinges, and pull rods. The scraper blade has different shapes and can excavate side ditches with triangular or trapezoidal cross-sections. In front of the scraper, there is often an adjustable soil scraper installed to loosen solid soil and facilitate the scraper's leveling operation. The front end of the host can also be equipped with a bulldozer, as well as additional devices such as snow sweepers and plows. Land levelers often use hydraulic mechanical transmission, where the power of the engine is output through a hydraulic torque converter and gearbox, with multiple walking speeds. The driven steering wheel is equipped with a tilting mechanism to tilt the wheels and improve the stability of the land leveler when working on slopes. Large graders also use articulated frames, with smaller turning radii and higher maneuverability. There are also machines that operate the position of the scraper using a pull rod and crank connecting rod mechanism, known as mechanically operated graders, which have become obsolete.
The current flatbed machines mostly adopt all wheel drive, all wheel steering, articulated frame, hydraulic control, and hydraulic mechanical transmission, and attach importance to the development of tires, using grooved wide base low-pressure tires to improve the smoothness of mechanical operation. The future development trend is to increase the variety and specifications of additional working devices, expand the operational performance of the host, and improve the driving speed of the host. The tire pressure regulating device, automation system, and instruments are used to manipulate various movements of the scraper, and the flatness of the working surface can also be controlled by a laser instrument.
The main technical parameters of a grader are engine power and scraper length.
