Transportation and Final Assembly

Transportation

The engine, frame, axles and differential requires six to seven semi-trailer truck loads, the cab requires one semi-trailer load, the six tires require two semi-trailer loads and the dump body requires four semi-trailer loads. In total, one 797 requires 12 to 13 semi-trailer truck loads that originate at various manufacturing facilities and deliver to the customer site. If a 797 must be moved from one job site to another for any reason, it can not be driven on public roads due to its exceptional size and weight. Moving a 797 requires dis-assembly, loading onto semi-trailer trucks, transport and re-assembly at the new location.

Final Assembly

Final assembly of the 797 is completed by Caterpillar field mechanics at or near the customer site. Before the dump body can be joined to the frame, the dump body components must be assembled and welded together by a dedicated team, requiring seven to ten days per dump body. Final assembly of one 797 requires a team of seven mechanics working in three shifts around the clock, seven days per week for 20 days in addition to the time required to assemble and weld the dump body.

Manufacturing and Assembly

Manufacturing and Assembly

Major components of the 797 are manufactured and assembled at six Caterpillar or supplier facilities located throughout North America, then shipped to the customer site for final assembly by Caterpillar technicians.

The engine is manufactured by Caterpillar in Lafayette, Indiana and is then shipped to Caterpillar's Decatur, Illinois assembly plant.

The tires are manufactured by Michelin North America at the US7 Earthmover Manufacturing plant in Lexington, South Carolina and are shipped to the customer site.

The driver's cab is manufactured by Bergstrom Climate Control Systems' Contract Assembly division in Joliet, Illinois. Each cab is assembled by one person and requires forty hours to complete. The cab is shipped to the customer site.

The dump body is composed of five components: the floor, the two sides, the front wall and the canopy. The dump body is shipped in component form to the customer site where it is assembled and welded into one monolithic structure before being joined to the frame during final assembly.

The frame is created from nine individual metal castings manufactured by Amite Foundry and Machine Inc. in Amite City, Louisiana. The smallest casting weighs 500 lb (230 kg) and the largest casting weighs 12,000 lb (5,400 kg). The rough castings are shipped to the Caterpillar Decatur, Illinois assembly plant.

At Caterpillar's Decatur, Illinois assembly plant, the castings are machined to provide clean welding surfaces. The nine castings are placed in a jig and are then joined together by human welders. The frame is moved to a second welding station for further welding by robots. The third and final welding stage is completed by human welders. To ensure quality, welds are tested using an ultrasonic flaw detector. In total, 275 lb (125 kg) of welding wire is used to join the individual castings into a monolithic frame.

Hydraulic lines and electrical wiring are attached to the frame before the powerplant is joined with the frame. The frame/powerplant assembly and the axles are shipped from Caterpillar's Decatur, Illinois assembly plant to the customer site.

Wheels and Tires

Wheels and Tires

The Caterpillar 797 series haul trucks run on the largest tire in the world, the 4.028 m (13.22 ft) tall, 5,300 kg (11,680 lb) Michelin 59/80R63 XDR. This radial tire was developed by Michelin in conjunction with Caterpillar specifically for the 797. Six tires are required per truck at a cost of approximately USD $42,500 per tire.

Each wheel is attached to the axle using 47 nuts that are torqued to 2,300 ft·lb (3,118 N·m).

797 Engine

797 Engine

A gross 3,400 hp (2,535 kW) [net 3,211 hp (2,394 kW)] Cat 3524B HD EUI 24-cylinder, high displacement, electronic unit injection, quad single-stage turbocharged, aftercooled, four-stroke diesel engine powers the 797. The Cat 3524B HD engine is a tandem unit consisting of two 12-cylinder Cat 3512B HD engine blocks coupled to operate as a single engine.

797B Engine

A gross 3,550 hp (2,647 kW) [net 3,370 hp (2,513 kW)], twin turbocharged version of the Cat 3524B engine powers the 797B. The power rating of the 3524B is valid up to an elevation of 8,500 ft (2,591 m) or 15,000 ft (4,572 m) with a high altitude arrangement.

797F Engine

A gross 4,000 hp (2,983 kW) [net 3,793 hp (2,828 kW)] Cat C175-20 ACERT single block, 20-cylinder, electronic common rail injection, quad turbocharged, air-to-air aftercooled, four-stroke diesel engine powers the 797F. The power rating of the C175-20 is valid up to an elevation of 7,000 ft (2,134 m) or up to 16,000 ft (4,877 m) with a high altitude arrangement.

Transmission

The 797 series haul trucks are equipped with a rear axle mounted, computer controlled, seven speed planetary transmission with an integral lock-up torque converter.

Powertrain 797

Powertrain

The Caterpillar 797 series trucks employ mechanical drive powertrains in contrast to the diesel-electric powertrains of similar haul trucks offered by competitors. During initial development in 1997, a diesel-electric powertrain was considered for the 797, but this powertrain configuration was not developed because Caterpillar considered a mechanical drive powertrain more appropriate for market conditions at that time.

Product Improvements 797

Product Improvements

Caterpillar introduced the replacement for the 797, the 797B, in spring of 2002. Caterpillar increased the power output of the Cat 3524B engine to cope with the 797B's higher payload capacity of up to 380 short tons (345 t), a 20 short tons (18 t) improvement over the 797. The first 797B units entered service with customers in October, 2002. Caterpillar introduced the latest 797 model, the 797F, at MINExpo International in September, 2008, and when it goes in to full production in late 2009, the 797F will replace the 797B. The 797F comes equipped with a new, more powerful and more efficient Cat C175-20 engine and an increased payload capacity of up to 400 short tons (363 t).

Development

Development

In 1997, Caterpillar decided to begin development of a 360 short tons (327 t) payload capacity haul truck to meet the demand from large-scale mine operators wanting to reduce operating costs at mines using 80 to 90 short tons (73 to 82 t) per pass shovels. Engineers at Caterpillar's Mining & Construction Equipment Division in Decatur, Illinois created a new design for the 797 using computer-aided design technology. This was the first time CAD tools had been used extensively to design a Caterpillar truck. Caterpillar first unveiled a completed 797 on September 29, 1998 at the Decatur, Illinois assembly plant. The first two 797's produced were transported to Caterpillar's Arizona proving grounds for testing. In the second quarter of 1999, the third and fourth 797's produced were the first to be placed in service with a customer at the Bingham Canyon Mine in Utah. Caterpillar put 18 additional 797's into service with mine operators world wide as production development units. Caterpillar began marketing the 797 in North America in 2000, with full world wide marketing following in 2001.

caterpillar 797 specifically

From Wikipedia, the free encyclopedia


Caterpillar 797

The Caterpillar 797 is an off-highway, ultra class, two-axle, mechanical powertrain haul truck developed and manufactured in the United States by Caterpillar Inc. specifically for high production mining and heavy-duty construction applications worldwide. The 797 is Caterpillar’s largest, highest capacity haul truck. The latest version, the 797F, offers one of the largest haul truck payload capacities in the world, up to 400 short tons (363 t).