Motor Grader

A grader , also commonly referred to as a motor grader , motor grader , or simply blade , is a form of heavy equipment with a long blade used to create a flat surface during grading. Although the earliest models were towed by horses and later by tractors, most modern graders are self-propelled and therefore technically «motor graders».

Typical graders have three axles, with steering wheels in front followed by a leveling blade, then a cab and engine over tandem rear axles. Some graders are also front wheel drive for increased productivity. Some graders have optional rear attachments such as a ripper, scarifier, or compactor. A blade can also be added in front of the front axle. A main blade extension can also be installed for snow removal and some soil grading work.

Power varies from blade widths from 2.50 to 7.30 m (8 to 24 ft) and engines ranging from 93–373 kW (125–500 hp). Some graders can handle multiple attachments or are designed for specialized applications such as underground mining.

Function

In civil engineering, «rough grading» is done by heavy machinery such as scrapers and bulldozers. Graders are used for «fine grading» whereby the angle, slope (or pitch) and height of their blade can be adjusted with great precision.

Graders are commonly used in the construction and maintenance of dirt and gravel roads. When building paved roads, they prepare a wide, flat base layer for the final pavement. Graders are also used to lay natural earth or gravel foundation pads to their final level prior to the construction of large buildings. Graders can produce sloped surfaces for drainage or safety. They can be used to create shallow V-shaped drainage ditches on both sides of highways.

Steering is via a steering wheel or joystick, capable of controlling both the angle and lean of the front wheels. Many models also allow the frame to articulate between the front and rear axles, allowing for a tighter turning radius and also allowing the operator to adjust the articulation angle for better material handling. Other implement functions are usually hydraulically actuated and can be controlled directly using levers, joystick, or electronic switches operating electro-hydraulic servo valves.

The graders are also equipped with state-of-the-art digital grade control technologies such as those from Topcon Positioning Systems, Inc. , Trimble Navigation , Leica Geosystems or Mikrofyn. They can combine both laser and GPS guidance to provide accurate grade control and (potentially) «supportless» construction. Manufacturers such as John Deere have also begun introducing these technologies during construction.

Story

First graders were drawn with people and draft animals. In the era of motorization via traction engines, steam tractors, trucks and tractors, such towed graders grew in size and performance. The first self-propelled grader was manufactured in 1920 by the Russell Grader Manufacturing Company, which named it the Russell Motor Hi-Way Patrol. These early graders were created by adding a grader blade as an attachment to a utility tractor. After buying the company in 1928, Caterpillar truly integrated the tractor and grader into one design, while replacing the tracked tractor with wheels, resulting in the Caterpillar Auto Patrol, the first rubber-tired self-propelled grader, launched in 1931.

Regional use

In addition to being used in road construction, graders can also be used to do roughly equivalent work.

In some regions, such as Northern Europe, Canada, and the United States, graders are often used for snow removal in municipal and residential areas. In the bush and grasslands of Australia and Africa, graders are often essential equipment on ranches, large farms, and plantations for laying dirt paths where the absence of rocks and trees means that bulldozers are not required.