Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

300 Chapter 10 Force and Force-Related Parameters

Caterpillar developed the 797 in response to mining companies that were seeking a means

to reduce cost per ton in large-scale operations. Therefore, the 797 is sized to work efficiently

with loading shovels used in large mining operations, and Caterpillar matched the body design

to the material being hauled to optimize payloads.

The new 797 mining truck is the largest of the extensive Caterpillar off-highway truck

line, and it is the largest mining truck ever constructed. The Caterpillar 797 mining truck has

a payload capacity of 360 tons (326 metric tons) and design operating mass of 1,230,000 lb

(557,820 kg). The Caterpillar 797 Mining Truck specifications include:

Engine model:3524B high displacement

Gross power at 1750 rpm:3400 hp (2537 kW)

Transmission:7-speed planetary power shift

Top speed:40 mph (64 km/h)

Operating mass:610,082 lb (1,345,000 kg)

Nominal payload capacity:360 tons (326 metric tons)

Body capacity (SAE 2:1):290 yd

3

(220 m3)

Tire size:58/80R63

A summary of some information about various components of the 797 truck follows.

Comfortable and Efficient Operator Station The 797 cab is designed to reduce operator

fatigue, enhance operator performance, and promote safe operation. The controls and layout

provide greater operator comfort along with an automotive feel, while enhancing functionality

and durability. The cab and frame design meets SAE standards for rollover and falling-object

protection.

The truck and cab design provides exceptional all-around visibility. For example, the clean

deck to the right of the cab improves sight lines. The spacious cab includes two full-sized air

suspension seats, which allow a trainer to work with the operator.

The steering column tilts and telescopes so the operator can adjust it for comfort and opti-

mum control. The Vital Information Management System (VIMS) display and keypad provide

precise machine status information. The new hoist control is fingertip actuated, allowing the

operator to easily and precisely control hoist functions — raise, hold, float, and lower. Electri-

cally operated windows and standard air conditioning add to operator comfort. The cab is

resiliently mounted to dampen noise and vibration, and sound-absorbing material in the doors

and side panels cuts noise further.

Cast Frame Mild steel castings comprise the entire load-bearing frame for durability and resis-

tance to impact loads. The nine major castings are machined for precise fit before being joined

using a robotic welding technology that ensures full-penetration welds. The frame design

reduces the number of weld joints and ensures a durable foundation for the 797.

The suspension system, which uses oil-over-nitrogen struts similar to other Caterpillar

mining trucks, is designed to dissipate haul road and loading impacts.

Electronically Controlled Engine The new Cat 3524B high-displacement diesel engine pro-

duces 3400 gross hp (2537 kW). It is turbocharged and aftercooled, and features electronic

unit injection (EUI) technology, which helps the engine meet year 2000 emissions regulations.

The engine uses two in-line blocks linked by an innovative coupler and precisely controlled

by electronic controllers. These electronic controllers integrate engine information with

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