Gutsy Graders Go with Joysticks

Sept. 28, 2010

Caterpillar M-Series motor grader
Notice the brand new Power Edge logo with the red slash on the new M-Series grader. The company is replacing the red beltline stripe with this new logo on all of its products going forward.
Joysticks Simplify Grader Operation

Left Joystick:

  • Side-to-side = steering
  • Twist = articulation
  • Right yellow button = auto articulation return to center
  • Top black buttons = wheel lean
  • Trigger switch = transmission direction
  • Top yellow buttons = gear selection
  • Fore/Aft = left blade lift
  • Detent = left blade float

Right Joystick:

  • Fore/aft = right blade lift
  • Detent = right blade float
  • Side-to-side = blade shift
  • Twist = circle turn
  • Hat switch fore/aft = blade tip
  • Hat switch left/right = drawbar shift
  • Differential Lock/Unlock
  • Electronic Throttle Resume/Decrement
By tapering the cab floor and angling the doors of the M-Series motor graders (top) ability to critical areas has been significantly increased from the H-Series (above). Listed below are functions of the new joysticks.

Ask any contractor what the most complicated piece of earthmoving equipment is to operate and the answer would most likely be a motor grader. After hearing that comment for decades, and after doing plenty of research, Caterpillar decided to address the issue by replacing all of the motor grader's conventional controls — including steering — with a pair of joysticks. At the same time, the company updated its grader engines to meet Tier III emissions requirements. Like the addition of hydraulics and articulation back in the '70s and electronics in the '90s, Cat's new M-Series joystick controls are a serious technological advancement in the motor-grader world. In fact, the company has applied for more than 100 new patents while developing these machines.

The seven new M-Series motor graders will replace the previous 10 H-Series machines. New models include the 120M, 12M, 140M, 160M, 14M, 16M and 24M — all of which will be operated with joysticks. Operating weights range from 29,000 pounds on the 120M to 145,000 pounds on the 24M. Blade lengths vary from 12 to 24 feet. The 120M, 140M and 160M will offer an all-wheel-drive option for improved traction in poor underfoot conditions. Production will start with the 14M in October 2006 and finish with the last model mid-year 2007.

Caterpillar unveiled these machines at its newly expanded Edwards Demonstration and Learning Center near Peoria, Ill. After a product overview, construction editors were encouraged to try the new motor-grader simulator, where we were tutored on the use of joysticks and practiced what hand/wrist motion accomplished what movements. After sitting down for just a few minutes, all of us in attendance were truly amazed at how intuitive the joysticks were to use and how quickly we learned which hand controlled which function.

Although Caterpillar says the M Series changes were spawned by the latest emissions requirements, it knew the time had come for more grader advancements. In 2000 through 2004, Caterpillar designed prototypes of the M Series and asked customers for feedback — and listened. They also surveyed 500 customers worldwide by phone, mail and in person to ask what keeps them up at night and what they could do to make their jobs easier. Caterpillar went back to their engineers with customers' suggestions and made some improvements. Then in 2005 and 2006 the company sent out field-follow machines to various customers and asked them to use them on jobsites for a period of time. Originally, Cat was going to offer a steering-wheel option for operators who weren't comfortable with the joysticks, but the seasoned veterans using the M Series units said they didn't want or need it.

All in all, Caterpillar says there is 35 percent new content in the M Series graders, including a few industry-exclusives. First, let's start with the cab, which is 5 inches deeper than predecessor models and 69 inches high. Because the cab is not defined by the width of the old console with levers, Cat had the flexibility to open up the interior and provide excellent sight lines to the drawbar, circle and moldboard (DCM) and snow-wing area. The cab features a tapered floor and angled doors, which dramatically increase visibility to the front tires and the heel and toe of the blade (see side-by-side photos). In addition, the sloping, tapered engine enclosure opens lines of sight to the ripper. Outside the cab, notice the black glare-resistant paint used on top of the frame, blade lift cylinders and engine enclosure. This helps the grader operator and also the surrounding equipment operators who won't see any glare.

The M-Series joystick-operated, electro-hydraulic control system simplifies motor-grader functions and is claimed to reduce operator arm and hand movements by up to 78 percent, according to a study done at the University of Wisconsin. According to Caterpillar, "the 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." For an explanation of joystick functions, see the sidebar above and notice the exclusive "automatic return-to-center button for articulation."

Caterpillar's motor-grader simulator with joysticks helps demonstrate how easy it is to learn the hand movements and to "dispel fear" among seasoned grader operators.

For the M-Series introduction, Caterpillar brought in three motor-grader customers who were part of the "field-follow" group of M-Series machines to comment on the joysticks and overall operation. Wayne Wood of Wayne Wood Grading (Phoenix) has been in business for 45 years and has operated motor graders for 36 years, Gary Longhe of Flagstaff County (Daysland, Alberta, Canada) has been using graders for 30 years, and John McAllister of Peterson Contractors (Reinbeck, Iowa) has operated a motor grader for more than 35 years. Comments made by these three men included, "you really can teach an old dog new tricks"; "this machine is awesome and easy to learn"; and "the M-Series is not a machine, she's a lady!"

In addition to all the joystick excitement, M-Series motor graders will be powered by new C-Series engines with ACERT technology and meet Tier 3 emissions regulations. Horsepower ranges from 125 in the 120M to 500 in the 24M machine.

Variable Horsepower (VHP) comes standard on all models, and Variable Horsepower Plus is an option. VHP and VHP Plus deliver additional gross horsepower in each gear, both forward and reverse. The horsepower is delivered in 5-hp increments in each gear. VHP as a standard feature delivers horsepower in gears 1, 2, 3 and 4; the horsepower level in 4th is held throughout gears 5 thru 8. If the customer has VHP Plus, the machine will deliver 5 more horsepower in gears 5, 6, 7 and 8. Higher horsepower in higher gears is necessary to carry blade loads at higher ground speeds, especially removing snow in 7th gear.

With more rim pull available in all gears, Caterpillar says the M-Series is much more productive than its predecessor models — more than 30 percent depending on the model.

An all-wheel-drive option is also available on the 120M, 140M and 160M, and is said to deliver 52 percent more torque than the H-Series. It uses dedicated left/right pumps, which allow independent control of hydraulic flow to each front wheel hydrostatic motor. Through an electronic control module, front-wheel speeds can be controlled automatically. Steering Compensation varies the outside and inside wheel speeds by 21 percent, so full torque is available through an entire turn, which allows a shorter turning radius. The system also has a front-wheel-only hydrostatic mode for precise, low-speed performance, providing infinite speed control from 0 to 5 mph.

Serviceability has been simplified with top-accessible drawbar wear inserts and bi-directional moldboard slide rail wear strips that make DCM adjustments faster, and they are now a one-person procedure.

In addition to power enhancements, Caterpillar has simplified maintenance. All service checkpoints are at ground level, including fuel fill. Top-accessible drawbar wear inserts and bi-directional, moldboard-slide-rail wear strips make DCM adjustments faster by 77 percent, Cat says, and they are now a one-person job. Slide rail shoes allow adjustment up and down as well as fore and aft, which eliminates moldboard chatter.

Attachments made standard are supplemental steering, AccuGrade-ready wiring, and tandem walkways with non-skid surface. A variety of optional attachments is also available.