- Pilot controls
- Hydraulic choices
- Couplers and comfort
- Average Backhoe-Loader Costs
- Basic Specifications: 14-Foot-Plus Models
- Volvo
- Case
- Komatsu
- Caterpillar
- John Deere
- JCB
- Terex
- New Holland Construction
When we asked product manager Scott Owyen at Terex to list what he considered to be significant recent technical advances in backhoe-loader design, he placed the Tier-II engine at the top.
Backhoe-loader buyers may well overlook the Tier-II engine's contribution to the machine's overall refinement, and that's understandable. The engine's use, after all, has been legislated, not developed primarily to make backhoes more valuable to the user. But as it turns out, these environmentally friendly engines, which are running with fairly stringent standards for nitrogen-oxide and particulate-matter emissions, actually deliver practical benefits.
Says Owyen of the Tier-II Perkins engines in Terex backhoes: "We're finding that these engines have increased horsepower, more torque, better fuel economy, lower sound levels and, of course, reduced emissions. Plus, maintenance intervals have been extended."
On the fuel-economy issue, CE field tests of Tier-II-compliant machines (of all sorts) have turned up fuel-efficiency improvements (the amount of material moved per gallon of fuel) ranging from 5 to 30 percent. For example, in a recent CE field test of a JCB New Generation 214 backhoe-loader against its predecessor model, the new machine averaged 10 percent better fuel-efficiency when trenching in moderately difficult conditions.
Fuel is not a big concern for every backhoe user, of course, as long as the machine gets through the workday without a visit from the fuel truck. Many users, however, are acutely aware of rising operating costs and are looking for every penny they can save. For this group, the apparent efficiency of Tier-II engines, coupled with their generally longer service intervals, may yield significant savings.
Every backhoe operator has a favorite control system, whether a two-lever arrangement with the boom on the left and the dipper on the right (or vice versa), a three-lever system with foot swing or a four-lever setup. What these systems have in common is mechanical linkage that connects the levers to the backhoe's control valve.
If it's been a while since you've looked at new backhoes, however, you'll find that the majority of manufacturers have added a new system to the mix-pilot controls. These new controls, which may be available for all or just select models in a manufacturers line, typically take the form of joystick controllers mounted in consoles adjacent to the seat.
When you move the joysticks, you're not pushing and pulling rods and bellcranks, but instead, simply shifting spools within a small hydraulic "pilot valve" at the base of the levers. Oil flow from the pilot valve is directed to the ends of the spools in the main valve, thus supplying the effort to shift the spools.
The advantages of pilot controls, say manufacturers, include considerably reduced lever effort, a more comfortable operating position (less leaning forward in the seat), and a better view into the trench, since the lever console at the operator's feet is eliminated. And, more often that not, pilot-control systems have a lever or switch that allows operators instantly to configure controls to their liking by switching the boom and arm functions side-for-side.
Yes, some operators object to pilot controls, saying that they jeopardize the "feel" of the backhoe-that is, the ability to sense through the control levers what the bucket is encountering in the trench. Perhaps it's just a matter of becoming accustomed to the slightly different inputs that new system delivers to the operator's hands.
Source:EquipmentWatch.com, phone: 800/669-3282
Hydraulic choices The issue of backhoe "feel," of course, also extends to basic hydraulic systems. Some operators swear that the widely used open-center system is best in this regard. "Open-center" means simply that the control valve is always open to receive all the oil flow that one or more fixed-displacement gear pumps can deliver. If the oil isn't needed, it returns to the reservoir.
Open-center systems, say operators who love them, not only clearly communicate what the bucket is doing in the trench, but also are particularly responsive, since the system's full volume of oil flow is, potentially, always available to satisfy hydraulic demands. Manufacturers using these systems claim further advantages, namely, the use of less expensive, more forgiving (of contamination) gear pumps, overall design simplicity and simpler, less expensive repair.
On the other side of the fence, so to speak, are operators who favor closed-center hydraulic systems. These systems typically use a variable-displacement, axial-piston pump that works with the control valve to produce only the volume of oil that's actually needed for the task at hand. Because the pump can regulate its output independently of engine speed, and because the system has the ability to sense loads in the various hydraulic circuits, the pump continually and automatically adjusts output volume for peak efficiency.
John Deere uses both open- and closed-center systems in its backhoe range, with the latter system fitted to the larger 410G and 710G models.
"The systems on the larger units allow more precise combined-function metering," says Bob Tyler, product marketing manager for Deere's backhoe line. "The cost goes up, of course, and according to some, the 'feel' goes down. But the system provides definite advantages: flow goes where it's needed, not where the machine chooses to send it, and it saves fuel. And, I'll add that I've never heard the 'lack-of-feel' complaint from a customer."
Like Deere, Volvo also uses both system types¡ªan open-center in its BL60 model, and a closed-center in the larger BL70. According to product specialist Bill Sauber, however, the BL60 has "flow-sharing" ability built into the valve, a feature that automatically maintains pressure and flow for each function and enhances multi-function operation.
Terex uses what might be called a hybrid system, closed-center in design, but employing twin gear pumps. According to the company, the system essentially combines elements and benefits of both the conventional open- and closed-center designs, including load-sensing capability and the ability to smoothly blend multiple functions.
Truth be told, you'll find it difficult to go wrong with any of the hydraulic systems offered on today's selection of backhoes. Some buyers may be swayed one way or the other, however, based on their perception of a particular system's value in their specific applications.
Case's Rusty Schaefer notes that backhoe buyers increasingly are specifying couplers for new machines to increase utility. Case, as do many backhoe builders, offers both a mechanical and hydraulic coupler for both ends of the machine. In addition, says Schaefer, Case offers an optional "integrated" hydraulic coupler on its 580 and 590 Super M models. As an integral part of the dipperstick, the coupler is designed to eliminate attachment offsets, to add no weight and to preserve digging forces.
Komatsu's Mike Oliver also sees more buyers opting for couplers as they look for ways to make their machine investment more productive. He sees multi-purpose buckets as the leading front attachment, followed by forks and brooms. On the backhoe end, says Oliver, different-width buckets, hydraulic hammers, compaction wheels and plate compactors are popular tools.
Says Terex's Owyen: "Even rental yards are now ordering machines with couplers and attachments."
A final refinement that's most noteworthy on today's backhoes is the comfort and convenience of the operator's environment. Cabs are larger, have more glass, and interior appointments are automotive-like. Available features such as pilot controls, suspension seats, ride-control and climate-control make long days not feel so long. And the wider availability of powershift and auto-shift transmissions makes the ride even more pleasant.
"Today, productivity is taking the direction of operator comfort," says Deere's Tyler. "Comfortable operators stay in the seat longer and get more done."
Dig
Depth
Weight,
Avg. (lb.)
Capacity
(cu. yd.)
** 80 horsepower w/turbo
*** Side-shift backhoe
**** 4x4x4 design (4WD, 4WS, 4 equal-size wheels)
^ Case specifications note a "sectional closed-center backhoe control valve with inlet compensator" when pilot backhoe controls are used.
| Web Resources | ||
| Terex www.terex.com |
Case www.casece.com |
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| Caterpillar www.caterpillar.com |
JCB www.jcb.com |
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| John Deere www.johndeere.com |
Komatsu www.komatsuutility.com |
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| New Holland www.newhollandconstruction.com |
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| Volvo www.volvoce.com |
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