Hyundai’s Robex 450-3 and 450LC-3 excavators offer four power modes, each designed to match engine speed, pump speed and system pressure with the current application. For high productivity or economic fuel consumption, the operator can choose the power mode that best matches the job conditions. The electronic control system determines the best engine speed and pump output for the greatest productivity and fuel efficiency.  The R450LC-3 has a boom of 7.06 m, an arm of 3.38 m and a bucket with a capacity of 2.09 m 3 . The maxi mum drawbar pull is 33 910 kg. The CAPO-II system on Hyundai’s Robex excavators includes the "Power Boost" button that is located on top of the left control lever. This button temporarily increases the digging forces for added power, for approximately eight seconds.

The phrase "application specific" has been used for different types of construction equipment, reflecting the needs of contractors and producers engaged in specialized fields. Design features on the PC1100-6 Avance hydraulic excavator from Komatsu include a 13 per cent increase in engine horsepower and traction force, a 16 per cent increase in bucket capacity, digging force and lift capacity. "These increases make this machine ideal for hard rock digging conditions that operators encounter in quarrying and mining, and some construction applica-tions," observed Scott Lynch, product marketing manager for hydraulic excavators. "The increase in engine horsepower results in fast cycle times and, when coupled with the larger size bucket, it greatly enhances productivity." Lynch notes that the increased digging force of the PC-1110-6 is especially practical (or application specific) for aggregate operations. The bucket size (4.2 m 3 ) can increase productivity by reducing the number of passes required to load trucks. Komatsu’s D/H operating mode, to increase power and reduce cycle time, has been adapted for the PC1110-6. "Using high engine torque, tenacious digging, such as required in hard rock digging, is possible, due to the quick recovery of engine revolution against a high load charge," is how Komatsu’s Lynch explains it. The PC1100-6 comes in three different models: standard, long undercarriage (LC) and super production (SP). The SP version has a bucket of 6.5 m 3 and a shorter reinforced boom and arm, as well as double bucket cylinders for handling the stress of larger size buckets used in harder digging applications.

The newest excavator from Komatsu is the PC270LC-6, a 27 953 kg machine powered by a 174 hp Komatsu turbocharged diesel engine. The new excavator features longer track lengths (5 m), wide track shoe widths (698 mm) and a 1.2 m bucket with what is claimed to be the strongest arm force in its class (12 074 kg). Five working modes are offered - heavy-duty, general, finishing, lifting and breaker operations. A key productivity advantage, states Lynch, is Komatsu’s patented HydrauMind all-hydraulic system that supervises the work operations of the excavator. Load-sensing valves and pressure compensated valves automatically handle all adjustments for individual jobs based on the pressure and lever stroke detected. This result is smoother, more efficient operations while being more ‘forgiving’ to the operator.

"There is a human being at the controls of an excavator," reads a notice from Hitachi. "The design philosophy of the new Hitachi EX Series excavators was to make the bond between the operator and the machine total." The EX135 and EX215 models (available in sizes where the weight ranges from 14.4 to 21.4 tonnes) have the engine position turned 180Á compared with previous models, which places the hydraulic oil tank on the side opposite the operator compartment, removing a possible heat source from the cab. The size of the cab is larger, now 1.8 m long by 1.0 m wide. The operator can choose four different levels of power for the current job and the Advanced Hydraulic System, with an on-board computer, receives all input from the excavator’s main components, transforming them into real orders that allow the operator to dominate the machine’s performance. "Undoubtedly, the most significant technological innovation in this series is the concept of dynamic stability," continued the manufacturer. "An automatic lifting cylinder hydraulic shock absorber counter-balances the pressure inside the cylinders themselves, when locking the booms, and completely eliminates the risk of overturning during this phase of a job. It ensures stability, operating safety and precision."

Introduced at the CONEXPO-CON/ AGG Show, Caterpillar’s new 365B L is a 65 -tonne excavator (bucket range: 1.2 to 3.8 m 3 ) that has been designed as the replacement model for the manufacturer’s venerable 245 model for a range of applications including bulk excavation, quarry work and truck loading. The excavator is said to make a good loading match with three Cat truck models: D400E ll articulated hauler, 769D off-highway truck and 771D quarry truck. A range of front configurations is available to match the machine with the job. A reach front will also be available with three stick options and also a mass excavation front with two. The long undercarriage is standard. The new model is powered by a Cat 3196 ATAAC diesel engine rated at 279 kW and features Cat’s Advanced Diesel Engine Management System, or ADEM II, for longer engine component life, optimum fuel efficiency and low emissions. Given by the manufacturer as significant, practical design features in a description of this model are: an improved load sensing and electronically actuated hydraulic system, an ergonomic cab with better visibility and lower noise; the Vital Information Display System (VIDS), the Cat Electronic Technician service tool for quick diagnosis of critical excavator operating parameters and simplified maintenance.

Caterpillar sized the 5130B hydraulic shovel to loada Cat (777D or  any 90 tonne truck in five passes. This even pass match increases production and lowers system costs by assuring that the haulers are used to their best advantage. The 5130B can three-pass load a 775D quarry truck or a 773D off-highway truck.

Volvo Construction Equipment describes three new excavators it introduced as "general purpose" machines, the types that most contractors require for their everyday projects, signaling the company’s commitment to a broader range of construction equipment. Volvo says the EC280, EC340 and EC390 offer some of the highest digging forces and biggest engine outputs in their classes and, for complete flexibility in applications, two booms, four dipper arms and two bucket types are available. These excavators have the Excellence three-circuit hydraulic system with the ability to prioritize one pump circuit to each of the three digging movements for the greatest precision. To provide good digging geometry and a low transportation height, the new hydraulic cylinders have a long stroke. The bucket rotating angle is 175Á for a good vertical digging depth and a high dumping height. Two-step piston motors drive the crawler undercarriages of the EC280, EC340 and EC390, using planetary gearboxes, and features such as standard derailing shields prolong the life of the track chain. Customers may specify the EC280 and EC340 with narrow undercarriages. The Volvo 7- and 10-litre diesel engines (rated at 147 kW and 182 kW) are low emission and specially adapted to produce maximum torque fuel efficiency and power in the typical operating speed range of the excavators.

The Samsung SE280 LC-2 (a Samsung product from Volvo Construction Equipment) has an operating weight of 29 945 kg and flywheel horsepower of 132kW@1900rpm. The bucket capacities for this tracked excavator range from 0.65 to 1.70 m 3 . Special attention in the specifications is paid to the undercarriage, noting that the heavy-duty box section carbody is welded with high tensile strength steel and that the track roller frames are reinforced and welded to the carbody. The rollers, idlers and sprockets are permanently lubricated. The self-diagnostic monitor system of this Samsung excavator identifies any problem and simplifies troubleshooting procedures. There are more than a dozen models in the Samsung SE excavator series, with horsepower from 38 to 220 kW, and digging depths from 3.8 to 12 m. Maximum reach goes from 5.95 to 18.2 m and maximum dump height from 4.1 m to 12.57 m. The 90B Series for Case Corporation expanded with the 9045B and the 9030B Narrow. This model is built from the same platform as the current 9030B but has been modified to provide the power within a machine that is only 2.59 m wide. "We are providing the maximum lifting and productivity in a machine that can be trailered without the restrictions encountered using wider units," explained Joel Borgardt, Case marketing manager. This addresses a practical, everyday problem for contractors. "It will improve our customers’ ability to move the machine from job to job."

Gradall has introduced the XL 3200 and says it is the first of its kind anywhere (apart from its attractive new colors). A crawler-mounted excavator in the 15 650 kg class, the XL 3200 has high pressure, load-sensing hydraulics and the company’s traditional boom that telescopes and rotates 220Á to  imitate the action of the human arm and wrist and give good attachment operation. Powered by a Deere 4045 engine, this excavator is deemed suitable for high productivity mass excavation, loading and unloading, pavement removal and demolition, and also for the more delicate operations of sloping and ditching. The telescopic design allows the machine to be used at sites where overhead space is limited, such as under bridges.

Several manufacturers of excavators mention "work modes". On John Deere’s 110 excavator, the work modes prioritise hydraulic flow for the operator, according to the current job. The Dig mode is suitable for general excavating and the Grading mode finds the arm in speed reduced for fine grading. In the Precision mode, all function speeds are reduced to suit heavy loading and placing, while the Attachment mode regulates the oil flow to match the attachment being used, to give smooth movements even for the more complex functions. The 110 excavator has a variable flow hydraulic system that balances hydraulic pressure and flow, to help the engine maintain maximum efficiency. The 110, in the 11 to 12 tonne class, offers a digging depth of 5.5 m, a reach of 8.05 m, 2950 kg of lift capacity over the front, 4900 kg of arm force and 8909 kg of bucket digging force with an arm of 2.82 m. In other product developments, John Deere recently unveiled its 80 excavator to compete in the 6 to 8 tonne class as the replacement model for the 190E, the 330 LC in the 28 to 33 tonne class and the 370 in the 33 to 40 tonne class. The smallest in John Deere’s excavator line, the 55 hp 80 has an operating weight of 7529 kg, 6.7 m of reach, 4.6 m of digging depth, 5360 kg of drawbar pull, 5089 kg of bucket digging force and a 2.74 m track length. The 330 LC, replacing the 892E LC, weighs in at 33 058 kg and provides increased horsepower, lift capacity, arm force, bucket breakout force, drawbar pull and counter-weighting than its predecessor. At 36 832 kg, the new 370 incorporates larger undercarriage components from Deere’s 450LC excavator for extra versatility. Both the 330 LC and 370 models feature Deere’s Powerwize engine/hy-draulic management system and are powered by a fuel-efficient, clean-running 235 hp John Deere POWERTECH 8.1 l diesel engine.

LBX Company (the manufacturers of Link-Belt excavators) recently announced the availability of the 8000 Quantum hydraulic excavator in a standard and mass version (1.34 m 3 to 4.59 m 3 ) bucket rating. The standard excavator is 80 000 kg and the mass excavator is 80 300 kg. Boom length for the standard model is 8.4 m and 7.25 m for the mass version. The 8000 Quantum has a long undercarriage, a Nephron oil filtration system, an illuminated LCD service monitor, and the traditional operators’ control station found on all Quantum models. A most practical feature is the Easy Maintenance System (EMS) which extends grading intervals from an industry standard of 50 hours to 1,000 hours or six months. (There’s another design development in excavators that is not obvious but valuable in the field.)

There are eight other, smaller models in the Link-Belt Quantum series, with weights ranging from 6,000 to 45 269 kg. q