Caterpillar launches G-series wheel tractor scrapers 
(04/10/2006)
The new Caterpillar G-series wheel tractor scrapers 621G, 623G, 627G, 631G, 637G and 657G have been improved to boost productivity and lower operating costs. The 627G, 637G and 657G tandem-powered machines have new electronically controlled scraper engines that incorporate dual power capabilities, just as the tractor engines do. Each of the new scrapers has a new productivity enhancing operator station, a redesigned scraper bowl with 10 percent more capacity, and the latest electronic monitoring system to simplify maintenance.
All G-series wheel tractor scrapers incorporate Cat's EU Stage IIIa compliant ACERT Technology engines. The electronically controlled engines feature the Caterpillar HEUI fuel system and comply with current emissions regulations. Each engine is electronically integrated with an automatic planetary powershift transmission to provide maximum power to the cutting edge and high-production haul road speed. The engines ranging from C9 to C15 and C18 provide advanced electronic control, precise fuel delivery and refined air management for outstanding engine performance.
ACERT building blocks include:
Fuel delivery: The multiple-injection process introduces fuel into the combustion chamber in a number of precisely controlled "microbursts". Injecting fuel in this way allows for precise shaping of the combustion cycle. For optimum performance, the multiple-injection process can be tailored for different applications and engine sizes.
Air management: Advanced air management also plays a critical role in reducing emissions. Stage IIIa off-road engines include crossflow heads and wastegated turbochargers. Advantages of wastegated turbos include higher boost levels over the entire operating range resulting in better low-end performance and response. Crossflow heads improve breathing for optimized combustion.
Electronics: The "brain power" for ACERT Technology comes from Cat ADEM 4 electronic controllers. The Cat ADEM 4 can govern fuel delivery and other engine processes with incredible precision. Cat ADEM 4 provides the ability to link machine performance directly with the engine.
The 621G, the 623G and 627G scrapers all use the Cat C15 as the tractor engine. The dual horsepower engine produces net power 246 kW in lower gears and 272 kW in higher gears. Heaped bowl capacity is 17 m3 for 621G and 627G and 17.5 m3 for 623G.
The 631G, 637G and 657G scrapers use the C18 as the tractor engine. The engine in the 630s produces a net power of 345 kW in lower gears and 373 kW in higher gears. The engine in the 657G produces 421 kW in lower gears and 447 kW in higher gears. Heaped bowl capacity for 631G and 637G is 26 m3 and for 657G 33.6 m3.
The tandem-powered 627G and 637G now incorporate the Cat C9 scraper engine for peak performance and high productivity in self-loading applications. The C9 for 627G is a dual horsepower engine with 178 kW while loading and dumping and 198 kW on the haul and return roads. The loading and hauling engine powers 637G for are 198 kW and 211 kW. The 657G features the bigger C15 engine. Dual horsepower capabilities enable the scraper engine to produce more power in higher gear ranges for improved grade-ability and reduced cycle times.
Redesigned operator station enhances productivity
The redesigned operator station promotes efficient operation throughout the entire work shift. A new, adjustable Cat Comfort Cloth Seat includes adjustable armrests, and it swivels and locks in four different positions to provide the optimum operating position in the cut or on the haul. The seat suspension features a self-contained air compressor with a high performance air shock absorber. The revised steering column increases legroom.
The redesigned hood has sloped corners to enhance sight lines. The exhaust is located at the back of the hood for enhanced sight lines to the right of the machine.
The improved scrapers retain the single lever implement control, which combines the traditional three implement levers—bowl, apron and ejector—into one joystick. The operator can raise and lower the bowl and actuate the apron and ejector with the single joystick. On appropriate models, a trigger on the joystick controls the auger or the bail. The transmission hold and cushion hitch switches are incorporated into the joystick as well.
Bigger, stronger scraper bowl
The redesigned scraper bowl increases bowl capacity 10 percent for each machine. The new design also improves draft arm protection and load retention. The low profile design offers less resistance to incoming materials, and cellular construction adds strength and dent resistance to the bowl sides and floor.
The bulldozer ejection system provides constant spreading control while minimizing carryback. A spill guard on the ejector helps retain material and keep it from spilling onto the rear of the scraper.
Designed to reduce service time
The Electronic Monitoring System, EMS III, monitors machine status and provides real-time information to the operator. The system warns of any problems detected by the electronic control modules governing all major systems.
The Caterpillar Electronic Technician service tool easily accesses real-time and stored information through EMS III. The design allows a service technician to diagnose a problem quickly and easily.
Caterpillar has made a number of small changes to the scrapers to improve reliability, durability, and access for service. For example, the implement valve has been relocated from the tractor to the top of the draft tube on the scraper. The change eliminates several hoses and tubes that crossed over the hitch. The result is fewer hydraulic components and connections and improved access.
The G-series scrapers also feature grouped maintenance and service points for simplified routine maintenance. Fluid filters are all spin-on style with the exception of the main hydraulic filter. Spin-on filters decrease maintenance time and reduce the chances of system contamination.
Auger, elevator and push-pull arrangements
Each of the new scrapers is available with an auger system in the bowl, which gives the machine a self-loading capability in material that ranges from free flowing to rock. The auger lifts material off of the cutting edge, conditions it and spreads it evenly in the bowl. In addition, the auger minimizes the production of dust while loading material.
The 623G with an elevator is ideal for windrowing, blending material as well as breaking up vegetation in stripping operations. The elevator lifts material off of the cutting edge, carries it to the top of the elevator, and then dumps the material into the bowl. The operator has variable control of the elevator to match the speed of the elevator to the material conditions for increased productivity. In addition, the elevator reverses for spreading topsoil and unloading cohesive material. The single-pivot elevator design improves the load profile, which allows the machine to achieve consistent payloads.
The 627G, 637G and 657G are available in a push-pull configuration designed for two machines to assist each other when loading. The push-pull arrangement features a hydraulically actuated bail and cushioned plate bolted to the front of the tractor and a hook attached to the rear of the scraper. This arrangement allows a pair of machines to link together when loading. Typically, push-pull scrapers achieve high production and low cost per meter.
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