CATERPILLAR  has announced a seven-model lineup of M-Series motor graders, applying for more than 100 new patents while developing these machines. They feature a number of revolutionary concepts in motor grader design – most notably a pair of joysticks replacing as many as 15 levers and a steering wheel. Because of the many control inputs required and the precision work performed by motor graders, they are widely regarded as the most difficult of all earthmoving machines to operate. Caterpillar designed the M-Series joystick control system to make the motor grader easier to learn and less fatiguing. New features include dynamic styling that opens up lines of sight, easy adjustment of the drawbar, circle and moldboard (DCM), a high torque all-wheel-drive system, enhanced power management and emissions-compliant Cat C-Series engines with ACERT technology.

The M-Series will replace the 10 H-Series models as the new machines are released starting in the third quarter of this year and concluding in mid-year 2008. The new models include the 120M, 12M, 140M, 160M, 14M, 16M and 24M. The 120M, 140M and 160M will offer an all-wheel-drive option for improved traction in poor underfoot conditions, such as snow, mud and sand, and for added steering and side draft control. The new M-Series joystick-operated electro-hydraulic control system simplifies motor grader control and reduces operator arm and hand movements by as much as 78 per cent. The pair of three-axis joysticks is built for comfort and low-effort operation, and feature a logical and intuitive control pattern. To reduce glare, the M-Series machines have black paint on the top surfaces of the front frame, blade lift cylinders and engine enclosure.

Top-accessible drawbar wear inserts and patented, easy-to-adjust, bi-directional moldboard slide rail wear strips make DCM adjustments much faster and more convenient. Shorter service times reduce owning and operating costs. By removing the access plates located on the top of the drawbar, a mechanic can maintain the circle by adding shims for wear strip adjustment or by replacing the wear strips when they are worn out. Changes to the moldboard retention system and the slide rail wear inserts make moldboard service much easier by eliminating the need for shims. The new bi-directional slide rail shoes allow adjustment up and down as well as fore and aft. The adjustment eliminates moldboard chatter.

The M-Series all-wheel-drive option delivers 52 percent more torque than the H-Series system. The M-Series uses dedicated left and right pumps, which allow independent control of hydraulic flow to each front wheel hydrostatic motor. To compensate for hydraulic power demand, the engine automatically delivers additional horsepower to provide constant net power to the ground. Through an electronic control module, front wheel speeds can be controlled automatically. The benefit of varying the outside and inside wheel speeds, known as steering compensation, is full torque through an entire turn. In poor underfoot conditions, this system allows a shorter turning radius. The M-Series all-wheel-drive system also features a new front-wheel only hydrostatic mode for precision low-speed performance. This mode provides infinite front wheel speed control from 0 to 8 km per hour for enhanced control when working in tight areas, such as cul-de-sacs.

Variable horsepower is now standard on all M-Series models, and Variable Horsepower Plus is optional. The M-Series power management system delivers additional horsepower in 5 hp increments as the transmission gear selection increases. The result is a smooth power curve that allows M-Series machines to carry heavy loads while downshifting. The previous system delivered an extra 20 hp in gears 4 through 8, and VHP Plus added another 20 hp in gears 7 and 8. Smaller increments throughout the gear range provide predictable power that operators prefer.

Source: Construction Contractor