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Caterpillar makes grade with upgrades

Cat has rung the changes with overhauls to its wheel tractor scrapers and articulated trucks, as well as its next generation of motor graders.

Caterpillar has been busy over recent months and has launched several new additions to its vast array of machines. One of the big pieces of news is the overhaul of the H Series wheel tractor scrapers which went into production in July.

Product and application specialist Angel Luis Gonzalez Suarez says: “The key message is that a machine that hasn’t changed in two or three decades has had a major update. It’s a big change for us,” he says.

These machines, with an up to 70 km road speed, can work alone and are used for grades and compaction and loading and hauling as well. They typically work rock that’s less than 400 mm, clay and topsoil shot rock, decomposed rock, sand and gravel, iron ore, mineral sand and coal.

“They are often used for 40-60,000 hours including rebuilds,” says Mr Gonzales, “about 10 times the life of an on-highway truck doing similar work.”

Caterpillar says these low volume machines are now able to break even after strict cost control measures.

The line includes the 621H (single engine push pull configuration), the 623H, and the 627H twin engine scraper meaning it has one at front and one at rear for extra power.

Customer feedback

Overhauling a product line has allowed the company to make some fundamental changes. “We had the opportunity to start from the ground up and develop a new machine,” says Mr Gonzales. “We asked our customers and dealers for feedback on what they wanted and the feedback was a product that had lower cost to move material, was easier to operate as it’s getting harder to get skilled professional operators, that featured improve productivity, and also enhanced operator ride and comfort.”

He explains the machine has a new cab that’s similar to the rigid frame and articulated trucks, allowing for more operator room and better visibility.

“Safety is the number one priority on most of our customers sites. About 80 per cent of lost time accidents occur when operators are getting onto or off earth moving trucks. So we worked on this, for example with a fold down stair to get into the cab.”

He says another improvement is dampening under the seat which lowers vibration for the operator. It also now has three cameras, which provide visibility around the machine, for example to show when the push-pull machine has correctly disengaged.

Other advancements include better protection for hydraulic lines that now fit inside the machine, and a non-metallic fuel tank to reduce metal weight from the machine. This has also been moved for better weight distribution with a size increase to support full 10 hour shifts.

Three levels of control technology include a sequence assist, which automates core work cycles and simplifies implement controls, which Caterpillar is keen to point out, reduces operator fatigue – meaning safer operation.

The load assist automatically adjusts cutting edge height, which ensures consistent bowl loading and maintains a full load. This helps eliminate tyre spin and so increases tyre life.

And Cat grade control ensures the machine digs to the final design grade, so surveyors don’t need to check grade levels. It also helps prevent overcutting and consequent reinstatement measures.

Articulated trucks

Another line getting a makeover is the B Series articulated trucks. Marketing product specialist Rob Macintyre says the main themes are operator comfort, simplicity and performance.

He says: “The new B series is the most important new product introduction in the last 10 years. But the key thing for any haulage unit is to optimise the power train so the engine power gets transferred to the ground as efficiently as possible.

The old trucks required operator to hit the differential locks foot switch 200 to 300 times a day when going up a grade or going through deep mud. “And you have to remember to do it every time,” says Mr Macintyre. “But it’s now automatic traction control although there are still four differentials on machine, one on each axle and one between first and second axle.

“In addition, the differential used to be 100 per cent on or 100 per cent off,” he says. This also means operators can’t panic in extreme conditions, operate a differential incorrectly, putting 500 hp through one at the wrong time and blowing which would cause untold damage.”

Caterpillar says that the new transmission control strategy is like the change between night and day compared to the old machine. But it still has the same basic 7F/2R transmission. However the company has improved the shift control, meaning electronic clutch pressure control for a smoother shift. Further improving efficiency is part throttle shifting. This essentially translates to shifts lower down rev band, as soon as there’s enough torque from the engine, and this increases fuel efficiency. And finally, it has shift torque management which Caterpillar says provides greater and smoother acceleration.

Mr Macintyre says customer feedback made it clear that the operators seat was their most important part of the machine, so it features improved suspension and increased vibration suppression with a new cylinder, increased adjustment, a more durable cover material and a heated option.

“We have Upgraded the HVAC with a 60 per cent increased in air conditioning performance with higher capacity AC components and improved cab sealing.”

Better ergonomics

The ergonomics have also received some attention. Client feedback indicated that a suspended foot throttle was not the most comfortable position and could cause foot and ankle fatigue, so it’s now mounted on the floor of the cab.

“It was amazing the amount of operators that said they wanted a grab handle for when the machine starts shaking or tilting, which we’ve added,” he says. “Previously operators have had to grab the steering wheel or shift levers.”

One piece of important customer response however was that they wanted machines that were simpler to operate to give peace of mind that inexperienced operators can work productively. Equally importantly, they said that after a day’s operation there shouldn’t be a big repair bill, particularly after a machine has got into trouble.

To help address these concerns, the machines now sport wider headlights for improved front spread of illumination, and width position marker lights so operators can make better judgements in low light conditions. And Mr Macintyre finishes saying other protective features are fully enclosed belly guards and an exhaust silencer that is no longer exposed.

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