The new John Deere D-Series Motor Graders--including the 672D/772D/872D six-wheel-drive graders and 670D/770D/870D tandem-drive graders--feature numerous enhancements that improve comfort, control and operating ease, boost productivity and increase uptime.
When designing the new machines, John Deere engineers consulted two customer advocate groups--one comprised of contractors and the second of governmental customers. Participants, which included operators and equipment owners from all regions of North America, provided valuable input into the design and development process. They had the opportunity to use prototype machines on their work sites and continued to make suggestions for improvements.
The changes begin with the new cab, which has been completely redesigned to improve comfort, convenience and visibility. Bonded windows reduce frame size, providing more glass and a better view of the blade and work area. A newly-designed heating, ventilation, and air conditioning (HVAC) system provides increased air flow and more efficient heating and cooling, keeping the operator comfortable and the windows clear. A new multifunction monitor provides vital operating and diagnostic information and is well positioned for excellent front visibility. An all-new sealed switch module with backlit pushbuttons is conveniently located to reduce operator fatigue.
Control also has improved, with best-in-class lever efforts and pressure-compensated load-sensing (PCLS) hydraulics that ensure consistent response and precise metering. Low-effort hydraulic controls provide ease of operation for the blade, circle, wheel lean and other hydraulic functions. The number of steering turns has been reduced, cutting down on the amount of arm motion required to turn the D-Series by 20 percent. For even more control and convenience, the D-Series graders feature optional cruise control, which allows the operator to set and maintain a constant engine speed. Another control feature, autoshift, automatically shifts between 4th and 8th gears when set by the operator.
With horsepower ranging from 185 to 245, the D-Series motor graders feature John Deere PowerTechâ¢ engines with 25 to 40 percent torque rise for better lugging. Another new feature is John Deere's exclusive event-based shifting transmission, or EBS, which senses the load and automatically adjusts the clutch-pack engagement accordingly. The result is smooth shifting that dramatically reduces the need to use the inching pedal.
Work tools have also been improved. The curvature on the moldboard has been redesigned for more efficient material movement. Throat clearance has been increased, which reduces material build-up between the top of the blade and the bottom of the circle. The draft frame pivot has been raised, allowing the operator to make circle rotate adjustments quickly and confidently. And the blade is pre-stressed for increased strength and durability. Several changes to the overall design of the machine increase productivity and durability. A longer wheel base levels out the machine's geometry for enhanced fine grading and a smoother ride. Additional weight has been added for better balance and traction. The mainframe has been strengthened for increased durability, and the electrical system features a solid-state load center, which dramatically reduces the amount of wiring, fuses, relays and connectors.
Source: John Deere, March 16, 2005