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This paper describes the concept and design of the Caterpillar “G” series motor grader transmission and transmission controls. Comments on vehicle performance, power train, and oil system requirements are included. Countershaft directional clutches are combined with six or eight speed planetary ranges for this family of articulated motor graders. The pilot-operated hydraulic control provides smooth rapid gear ratio changes and “inching” modulation for the pressure lubed directional clutches.

THE HYDRAULIC SYSTEMS for the Caterpillar “G” Series Motor Graders were designed to provide for maximum operator comfort, ease of operation, and optimum control of the vehicle and implements. The use of high pressure closed center systems on these machines produces rapid system response and high hydraulic horsepower to the implement cylinders and motors, and operates with minimum size control components. Components were designed to meet specific system requirements for functional performance, reliability of operation, size and placement on the machine. System goals were met through the use of a variable displacement pressure compensated pump, controlled flow four-way implement valves, and a hydrostatic steering system.

ISO and SAE static sound power test methods are currently used for construction machinery. The European Economic Community sound committee has been developing a drive-by or simulated work cycle test method using a hemispherical array of microphones. The EEC method is inconsistent due to the changing test surface (moist sand) and the variables of outdoor testing: temperature, wind, and precipitation. The in-place-dynamic test method described provides a disciplined way to evaluate machines with moving track or wheels and operating hydraulic systems. The machine is slightly elevated, resting on stands, so that the wheels are off the ground or the tractor weight is off the track chain. Data obtained from track-type tractor, track-type loader, and wheel loader machines supports the validity of using an indoor, in-place-dynamic test instead of a moving, outdoor test. Results also show that using sound intensity instrumentation permits the option of testing in an untreated, indoor facility.

For some time, Caterpillar Tractor Co. has been marketing a new transmission control system for wheel-tractor scrapers and off-highway trucks. The new system is composed of an electronic microprocessor control box coupled with an individual clutch modulation hydraulic control. This system has resulted in increased vehicle productivity, improved reliability and serviceability, decreased complexity, and increased commonality of parts. This paper describes the concept, design, and test and evaluation process used to develop the new controls before production.

Caterpillar recently introduced its first backhoe loader - a significant extension to the existing product line of construction equipment. It is a highly versatile machine entering a well-developed marketplace. This paper describes design considerations, the development program, and vehicle design features associated with the 416 Backhoe Loader.