For this installment of Hands-On-Earthmoving (HOE), JCB delivered a new JS 220 hydraulic excavator to the evaluation site, the Apprenticeship and Skill Improvement facility that Local 150 (International Union of Operating Engineers) operates in Plainfield, Ill. Our HOE operators, whom you've met before, were Tim Yednock and Gene Held, instructors at the facility. Actually, we got more in the bargain than we expected-the opinions of Tim and Gene about the JS 220, of course, but also their views about how best to run an excavator, plus a lesson about sizing buckets for productivity.
The JS 220, introduced in North America last fall, is classed as a 22-metric-ton machine and is among the first of JCB's "New Generation" JS-Series models. The new JCB excavator line will top out with the JS 460, a 305-horsepower machine with an operating weight in excess of 46 metric tons.
Probably to the surprise of some, JCB is not a novice at building larger equipment, and its excavator history actually goes back to an early-1990s joint venture with Sumitomo. Although this arrangement ended in 1998, JCB maintained its established supply lines to Japanese component manufacturers and tapped these sources as it developed its own excavator range.
David Morice, product marketing manager for JCB's heavy line, represented JCB at the HOE evaluation and gave Tim and Gene a walk-around introduction to the JS 220. The machine was equipped with 28-inch track shoes and a 9-foot 10-inch digging arm. Digging-arm options include 6-foot 3-inch and 7-foot 10-inch versions. The bucket was 42 inches wide with a capacity of 1.29 cubic yards.
Several of the machine's design details immediately caught the operators' attention. Gene liked the way the cab's front glass stored. The bottom panel slips upward and locks behind the larger upper panel, then this entire assembly slides easily upward and stores in the front portion of the roof.
"I have the front open even in the winter time," said Gene, "because there can be distortion through the glass. This is a handy storage system, because you don't have to remove the lower panel and store it in another spot-which is a pain."
We knew from working with Tim and Gene that they like being able to easily switch between the ISO and SAE lever patterns, because some student-operators, they say, have difficulty adjusting from one to the other. The JS 220 has this feature, and the switch for changing the pattern is behind the seat to prevent unintentional changes.
Both operators also took interest in the switch icons displayed in a panel that follows the curve of the right windowsill. Among the switches are those for emergency-stop, hydraulic-circuit cushioning, swing lock and lifting-overload warning, the latter a European requirement. The right console has the electronic throttle and a switch for selecting either boom or swing priority.
Regarding serviceability, both operators were impressed with the JS 220's features. Tim's initial observation was about the skid-resistant panels used on the top deck.
"When you're servicing the machine and the deck is wet or covered with frost," he said, "you can easily end up on your backside. These skid plates provide solid footing."
Another feature the operators thought handy was the electric refueling pump, located in a compartment at the machine's forward right corner. The pump, explained Morice, allows refueling the machine from drums when no service truck is available. An added convenience, he said, is a cap for the hose to prevent fuel not drained from the hose from spilling into the compartment.
Both operators took note, also, of the Plexus filtration system, a secondary hydraulic-fluid filtering system that continually bypasses a small amount of fluid through a 1.5-micron filter, resulting in 5,000-hour intervals for fluid changes. Both agreed, too, that JCB's use of an auxiliary filter in the hammer-return circuit was good idea, since it minimizes the risk of contaminating the machine's hydraulics with dirty oil from a rented hammer. Gene also said that color-coding the hydraulic hoses was an excellent idea, one that he had not seen before.
As Tim and Gene ran the JS 220, we asked them to first trench with the machine, using it in each of its digging modes-"automatic" and "economy". (The machine's Advanced Management System (AMS) allows the operator to select four work modes, the two just noted, as well as "precision" for grading applications, plus "lifting". We then asked them to load a truck, and last, to experiment with the machine's lifting capability.
The material in which Tim and Gene dug was stubborn, hard-packed clay laced with rock. It's the stuff, they said, in which they typically certify their students on excavators and backhoes. After trenching with the JS 220 through this tough soil, Gene told us that he had to run the machine in "automatic", because that setting gave the most power. The economy mode, he said, did him no good, but he acknowledged that in softer material it could be of advantage.
"When I'm working an excavator, even when grading, I want the maximum power the machine can deliver, then I use the levers to feather into functions. That's the philosophy I use with my students, and I get after them if they're running at less than maximum rpm. Get all the power you can, then handle the rest with the levers."
(Morice made the point that the work modes in JCB's New Generation excavators are engineered to precisely adjust machine performance for specific tasks. Seems as if manufacturers building excavators with work modes, along with their dealers, still have some ground to cover in this regard with end users.)
Gene commented that JS 220's hydraulic system was smooth, and, after getting acquainted with the machine, he said, the system allowed him to sense "what was going on in the trench". A jerky hydraulic system, he said, won't let you do this.
"In all honesty, a machine this size digging in this hard stuff would do better with a smaller bucket," Gene said, "because the hydraulics were working pretty hard. I noticed that when I pulled in the stick and got into the end of the cut, I'd have to work the bucket a bit. But it's not that big of a deal."
Anything else about the machine you noticed when digging?
"I'd like to see the travel levers come up and back a little farther, because I think you have to reach too far for them. They need a little curve to them at the top. But, again, it's no big deal; it's something you get used to. Everything considered, the machine is very comfortable."
When Tim had completed the trenching exercise, we asked for his comments.
"Visibility is good, it's quiet and smooth, and it's a stable machine. But like Gene said, if you're not in the automatic mode, it cuts down on the power. The weight in the bucket doesn't seem to bother it, it comes out of the trench just fine, but it seems to need more crowd force, at least in this material."
"As far as I'm concerned," said Gene, "you wouldn't want anything bigger than, say, a 36-inch bucket on a machine this size if you're in hard digging. Most contractors try to use the biggest bucket they can find, thinking that they'll get the best productivity. Really, though, in some materials, the bigger bucket slows them down. It's all about cycle time-get a bucket load and get out."
(In fairness to JCB and the JS 220, Morice did his best to get a smaller bucket, but without success. Buckets, we learned, given the upturn in equipment sales and the steel crisis, are hot items these days.)
In the truck-loading exercise, the operators found no fault with the JS 220, saying that it handled the bucket well to the truck with adequate speed. Both said that they would use the machine in its boom-priority mode (it's default setting), versus the swing-priority mode.
"When you're loading trucks, you have to be careful with the swing," said Gene. "You can't come in going as fast as you can. You have to swing into it easy."
In the lifting exercise, Gene picked an empty stone box, a concrete manhole and one end of a large trench box. In his opinion, the machine seemed a competent lifter and stable at these tasks. He admitted, though, that he found little difference in lifting performance between the lift mode and the automatic mode. But then again, for Gene, anything less than full speed is not the way to run an excavator.