Caterpillar has introduced a seven-model line-up of M-series motor graders. The M-series motor graders feature a number of new concepts in motor grader design, notably a pair of joysticks replacing as many as 15 levers and a steering wheel.
Due to the many control inputs required and the precision work performed by motor graders, they are widely regarded as difficult earthmoving machines to operate. Caterpillar designed the M-series joystick control system to make the motor grader easier to learn and less fatiguing.
Caterpillar applied for more than 100 new patents while developing the new M-series motor graders, and the new graders include about 30% new content. New features of the M-series motor graders include 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(r) C-series engines with ACERTTM Technology.
The M-series motor graders 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 M-series motor grader 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.
Joystick control simplifies work, opens lines of sight
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%. The pair of three-axis joysticks is built for comfort and low-effort operation, and they feature a logical and intuitive control pattern.
The M-series joystick-operated electro-hydraulic control system helps operators sustain high levels of efficiency throughout the workday, and the intuitive control design makes training fast and simple for both new and experienced operators.
The new M-series joystick-operated electro-hydraulic control system opens up the interior of the cab and provides good lines of sight to the DCM and snow wing area. The cab doors are angled and the floor is tapered to provide an unobstructed line of sight to the front tires, the heel and toe of the blade and the DCM.
In addition to changes inside the cab, the sloping, tapered engine enclosure opens lines of sight to the ripper. To reduce glare, the M-series motor graders have black paint on the top surfaces of the front frame, blade lift cylinders and engine enclosure.
Easier DCM maintenance
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 mouldboard chatter.
High torque all-wheel-drive
The M-series all-wheel-drive option delivers 52% more torque than the H-series system. The M-series motor graders use 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.
Advanced power management
Variable horsepower (VHP) is now standard on all M- series motor graders, and variable horsepower plus is optional. The M-series power management system delivers additional horsepower in 5 horsepower increments as the transmission gear selection increases. The result is a smooth power curve that allows the M- series motor graders to carry heavy loads while downshifting.
The previous motor graders delivered an extra 20 horsepower in gears 4 through 8, and VHP plus added another 20 horsepower in gears 7 and 8. Smaller increments throughout the gear range provide predictable power that operators prefer. With more rim pull available in all gears, M-series motor graders are more productive than their H-series predecessors.
New engines and drive train
Cat C-series engines with ACERTTM technology enable the M-series motor graders to meet U.S. EPA Tier 3 and EU Stage IIIa emissions regulations.
The C-series engines have been proven in highway truck applications and a wide range of earthmoving equipment. ACERT(tm) technology enables Cat engines to supply more power per unit of displacement while retaining the reliability and durability that customers expect from Caterpillar.
The M-series motor graders also have many new drive train features. The M-series motor graders have a bolt-on modular rear axle. The new axle module allows the axle and both tandem cases to be dropped down for servicing, which reduces service time.
All M-series motor graders except the 24 M feature a direct-drive countershaft transmission. Electronic clutch pressure control makes gear-to-gear as well as forward/reverse shifts smoother and prolongs the life of all drive train components.
The M-series motor graders carry over safety features from the H-series as well as incorporate some new additional features. Some of the safety features on the M- series motor graders are:
Operator presence system - The operator presence system keeps the parking brake engaged until the operator is seated for safe operation.
Secondary steering system - The standard secondary steering system automatically engages an electric hydraulic pump in case of a drop in steering pressure, allowing the operator to steer the machine to a stop.
Speed sensitive steering - The steering software automatically provides an infinitely variable ratio between the joystick and the steer tires, resulting in less sensitive steering as groundspeed increases.
Hydraulic lockout - A simple switch located in the cab disables all implement functions while still providing machine steering control. This safety feature is especially useful while the M-series motor grader is roading.
Low sound and vibration levels - Isolation mounts for the cab, engine and transmission maximize operator comfort and minimize transmission of sound and vibration. These modifications provide a quieter and more comfortable working environment, optimising operator focus.
Engine shutoff switch - An engine shutoff switch is located at ground level on the left rear of the machine, allowing anyone nearby to shut it down in case of an emergency.
Electrical disconnect - A battery disconnect switch, located inside the back left enclosure, provides ground-level lockout of the electrical system to prevent inadvertent starting of the machine.
Additionally, machine certification and operator licensing requirements for the M-series motor graders remain unchanged from the existing H-series in both Australia and New Zealand.
AccuGradeTM attachment ready option
The AccuGrade system is fully integrated into the M-series motor grader design, making installation quick and easy. Integral hydraulic and electrical components are standard on the M-series (grade control ready). The AccuGrade attachment ready option provides additional mounting brackets, cab controls and electrical harnesses for easy installation of the Cross Slope, Sonic, Laser, GPS or ATS electronic kits.
The Caterpillar AccuGrade System automatically controls the blade, improving operator efficiency and productivity.