Getting “jerked around” just seems to go with the territory in the excavation business. When the bucket smacks into something, it can jolt the whole machine, not to mention the operator.
Jerry Fisher has lived with it for most of his 35-year career. He’s an excavator operator with general contractor Buck Overby Construction (BOC), Inc., in Nashville, Tenn.
BOC specializes in commercial and industrial concrete work with a crew of 30 people. Most of the work is in or close to Nashville. It’s the third construction company that Overby has founded in his career – which he began as a summer bricklayer during high school.
“We dig a lot of footings for buildings and we do a lot of excavating; sometimes we demolish buildings,” says Buck Overby. “For years, our favorite excavator had always been Cat, but then we tried out Cat, Deere, Komatsu and Kobelco excavators. Kobelco, by far, outdid the others. It’s one good machine.”
Today, Fisher operates a Kobelco 135SRLC short radius hydraulic excavator. He’s still working hard, but the hours spent behind the excavator controls are a lot easier.
“For its size, I enjoy the smoothness of the Kobelco,” Fisher says. “A lot of excavators that are that small will bounce around and go whatever which way if you hit something hard There’s not a whole lot of jerking with the Kobelco. If you get in a bind or hit something, it’s still smooth.”
[Small, of course, is a matter of perspective. The 135SRLC weighs 30,800 pounds, has a reach of 28’ 9” and can do a vertical wall to a depth of just over 17 feet.]
Kobelco has borrowed technology from its line of industrial cranes to take the “ jerks” out of the system. Kobelco excavators use a swing shockless valve to provide smooth starts and stops, and precise bucket placement. The valve absorbs and dampens the effect of each shock and rebound encountered in normal operation.
At the same time, Kobelco resolved two other perennial concerns that require constant attention from operators. When operating an excavator, Fisher had always worried that the tail might swing around and hit something. He often felt a bit unsteady, feeling that the machine could tip.
In 2001, BOC was the first contractor in Tennessee to use the new Kobelco 130 short radius excavator. They purchased it from the dealer in Nashville and, about 2,300 engine-hours later, traded it for a Kobelco 135SRLC in late 2003.
Kobelco was introducing the short-radius swing in 2001. Overby wanted to switch to a Kobelco excavator, but also was nervous about the significant design change. However, his operator visited the factory and came away satisfied.
Today, short radius is a proven concept for excavators.
Overby says, “They’ve all got it now. For working in tight places, you can work with zero clearance. If you’re beside a building or a bridge abutment or a light pole or whatever, you don’t have to have any clearance for it. You had to have about three foot before.”
Fisher adds, “In our type of work, the zero tail swing is very good because we have to get up real close to banks, and it just sticks over about a foot beyond the tracks. You can turn very easily, without bumping into something.”
In fact, the 135SLRC has a maximum 5.1-inch tail swing.
Along with zero tail swing, the Kobelco excavator gives the operator a sense of being more secure – as though both feet are planted firmly on the ground.
“Moving and digging and whatever, it’s balanced real good,” Fisher says. “It feels like its stuck to the ground. It doesn’t feel like it’s going to turn over every time you go to move or every time you touch something.”
Engineering changes make the difference. The cab has low noise and vibration because it is suspended on encapsulated liquid-viscous floor plate mounts. Meanwhile, the operator is sitting in a seven-way adjustable seat in an air-conditioned, modern cab with ergonomic controls.
“Real good” hydraulics” and “very sensitive” controls go along with the jerk-free environment, zero clearance and firm balance, says the veteran operator.
Fisher says, “It just handles well. You sit, you’re relaxed, you’re not strained, and it’s as fast as you want to go with it, that’s for sure. You control the speed, but it’s fast.”
How fast?
Overby assigned the excavator to a Chattanooga contract where BOC was putting in footings for a complex of 18 theatres. The schedule allowed six weeks for the work. With the Kobelco 135SRLC and experienced operators, BOC completed the assignment in about ten days.
Why the difference? Fisher was on that job. He says, “Well, the Kobelco excavator just handles so well. You can trust it, is the way I see it, and go to the limits on it. It’s just a good little machine.”
Mechanically, Overby says, Kobelco excavators have been reliable. “We have not had any problems with it,” he says, referring to the new Kobelco 135SRLC. Other than routine maintenance, they’ve seen almost no shop time. When they have needed attention, the Kobelco dealer has provided excellent service.