Caterpillar operates several proving grounds around the world where company engineers routinely test the strength, reliability and performance of Cat machines and equipment. But Caterpillar doesn't own the proving grounds that matter most; they are the thousands of jobsites globally where - day in and day out - customers put their Cat machines to work.

Ricky Patterson figures that since 1954 - when his dad Jack bought his first Cat dozer and opened the business that became Patterson & Son - his family has subjected Cat tractors to some of the harshest real-world tests they have faced anywhere by putting them to work on the swampy, stump-filled jobsites like this one, near Black Mingo Creek in Williamsburg County, South Carolina, where the small, family-owned firm plies its trade.

Patterson & Son operates in what arguably is the timber industry's knottiest niche, cleaning up sustainable pine farms after loggers have harvested the 25- to 30-year-old trees.

The job sounds simple enough: Using their fleet of four Cat D6 Dozers, Patterson & Son plow through the tens of thousands of stumps the loggers leave behind, shearing them off at ground level but leaving their root systems intact. Several months later, the dozers return to prepare the planting beds for the saplings that will form the next generation of trees.

The work is a lot harder than it sounds, especially the stump clearing. Current logging industry practices compel contractors like Patterson & Son to wait seven to 10 months after the harvest before they can go in and begin to prepare a site for replanting. That gives the stumps just enough time, Patterson says, to "get seasoned."

"If you can move in right after the logger," he says, "those stumps are green and you can make pretty good time. Or if you wait a year and a half, then they start to decay and, again, you can make pretty good time.

"But if you go in when we go in, you catch them right at the worst time. They're hard as iron or cement."

Think of the stumps as Nature's equivalent of the anti-vehicle barriers placed outside of government buildings. For six decades, Patterson & Son have been driving their Cat dozers into them over and over again.

Like a Rock

Passion for Caterpillar runs in the Patterson family. When Patterson was a boy, his dad owned two racecars that his uncle Frankie Elliott drove at the speedways in the state. Both were painted Cat yellow. One was named "D7." The other was named "D8."

"My daddy always said "˜I'd rather have a serial number plate off a Cat than a brand new machine from somebody else because with that serial number plate at least I know I got something,'" he says.

"No matter what the situation, no matter how bad it gets, Caterpillar has never failed to stand behind us."

But Patterson insists the family's fanaticism is a function of the equipment's superior performance in a punishing application. Over the decades, he says he has watched as newcomers that underestimated the difficulty of the work and over-estimated the capacity of their non-Cat equipment tried unsuccessfully to break into the stump-busting business.

Patterson knows all his competitors who have stood the test of time. All five of them, he says, run Cat equipment exclusively.

Punishing Application

Patterson & Son's D6s are outfitted with special blades made by a Georgia company called Savannah Forestry Equipment. The strength of the Cat dozers, even in the muddiest conditions, coupled with the strength of the Savannah blade - forged from special steel called AR400 - make the stump-shearing work relatively straightforward, though it's not an especially elegant process to watch as the dozers crisscross the field.

"The reason we cut back and forth," Patterson says, "is if we're going through here and we see a big old stump to our left, we can go and bust it in half so when we come back the other way we can cut the other half off. Especially in a wet place, you have to think ahead."

What makes the work hard is the punishment it inflicts on the dozer's undercarriage, the system of sprockets, track shoes, pins, bushings, idlers, links and frame inside the track-chain that moves the machine forward and backward.

As the dozer crawls over the stumps and other debris in the field, the track chain flexes back and forth. That's no problem for the track itself, but it exerts extraordinary pressure on the rail portion of the undercarriage. Over time, that can cause the seals on the rail to fail and to quickly bring all work to a halt.

Those punishing conditions made Patterson & Son's tractors especially useful as Caterpillar worked in recent years to field test new undercarriage technologies like Cat SystemOne in the most extreme conditions and toughest environments. 

Back in the old days, before lubricated rails, dry-link undercarriages wouldn't last more than 600 hours out here, Patterson says. "They wouldn't break. But the internal wear was awful. When you opened it up it looked like a snake," he says.

The development of lubricated undercarriage systems, like Caterpillar's SystemOne with its rotating bushing, has tripled the life of the undercarriages on Patterson & Sons' Cat tractors. Patterson is pushing for more and confident he'll reach his goal with help from Blanchard and Caterpillar engineers.

"If anyone is going to solve a problem or build a better machine, it's Caterpillar. There's no doubt in my mind."

In the meantime, he says SystemOne has already demonstrated its cost effectiveness, reducing Patterson & Son's maintenance and repair downtime and part replacement costs.

"For someone out there doing a normal job, SystemOne can't be beat. They're liable to get 6,000 hours of wear on it."