Compact Excavators Mature

Jan. 1, 2010
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Sales of compact excavators have declined from their all-time high of 28,000 in North America in 2007, but manufacturers have not let up improving these little diggers. In fact, many features typically reserved for larger excavators have migrated to the smaller machines.

“When we brought out our D-Series excavators, we made a lot of changes that brought a lot of our technology and experience from large excavators to the small ones,” says John Deere’s Mark Wall, product marketing manager for excavators. “For example, we gave the compact machines two-speed propel with auto-shift in it. So if you’re propelling up a hill and you turn, or put the blade down, the excavator will automatically shift into low and give you higher propel power.

“We also offer auto-idle, which is a take-off from a larger excavator,” says Wall. “If you’re working a machine and then you don’t operate the levers for four or five seconds, the excavator will automatically go into low idle, to conserve fuel. And it reduces noise on the job site.”

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Other improvements from Deere include a high-backed suspension seat, cup holders, and 12-V power outlets.

Improved Fuel Efficiency
Bobcat also has auto-shift and auto-idle-and incorporates load-sensing hydraulics into its 3-ton to 4-ton machines. Load-sensing hydraulics spring into action on demand only, says Tom Connor, excavator product specialist with Bobcat. If a hydraulic system is not being used, the pumps de-stroke into a “waiting” mode. That improves the fuel efficiency of the hydraulic system.

Bobcat launched its M-Series of excavators in April 2009, and the new machines boasted an all-new hydraulic system. “We had to do a completely different pump-and-valve package to get to the smoothness and response we were looking for without compromising speed,” says Connor. “And we needed efficiency in hydraulics so we could get by with less horsepower.”

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Bobcat’s E32 and E35 compact excavators dropped in engine horsepower, from 40 to 33, to save fuel. “If you look at the list of customer priorities, the price of $4-per-gallon fuel sank in here,” says Connor. “Fuel economy became a driving force in the redesign of the machine.

“Additionally, we continue to expand the use of electric-over-hydraulic technology to accommodate improved ergonomics for operators. For instance, the new E32 and E35 excavators feature thumb-activated boom-swing control.” Bobcat offers 11 different excavator models, and nine of them are compact by definition (less than 6 metric tons).

All manufacturers have upgraded the engines in their compact excavators to comply with the EPA’s exhaust emissions standards. Deere offers five models of compact excavators, and four of them, including the recently introduced 40.5-horsepower Model 60D, all meet Interim Tier 4 standards. The fifth machine, the 14.8-horsepower Model 17D, meets final Tier 4 standards.

Those upgrades require tweaks to the cooling and fuel systems, Wall says.

Other changes at Deere include an angle blade for the 50D excavator. And Deere moved the control of the auxiliary hydraulic system from the right foot to the right-hand pilot lever.

Deere’s 60D excavator is the company’s latest addition to the compact lineup. With a standard arm and rubber tracks, it weighs in at 13,600 pounds and can dig 12 feet, 4 inches deep. With a long arm, the 60D can go 13 feet, 6 inches deep.

New From Caterpillar
Caterpillar offers 10 compact excavators with dig depths ranging from 6.8 feet to 13.7 feet. In 2008, the company upgraded the three largest machines in that range to D Series models-the 307D, the 308D CR, and the 308D CR SB (swing boom).

Caterpillar says those three machines, each with 54-horsepower Mitsubishi engines, outperform their predecessors with 22% higher bucket forces and 10% higher stick forces. Lift capacity was increased with the addition of a larger counterweight.

“As with most construction machines, these small excavators now have many big-machine features, such as spacious cabs and sophisticated hydraulics,” says a Caterpillar spokesman. Additionally, reduced swing radius (CR means compact radius) has become very popular in this size class of excavators.

Cat says its D-Series mini-excavators share a common operator’s station with larger Cat excavators. “The cab is quiet, roomy, and well-ventilated, with plenty of legroom,” says the company. “To improve communication between the operator and the machine, a new color monitor displays information in text rather than codes. It can deliver messages in 27 languages to accommodate a diverse work force.”

Volvo Weighs In
At Volvo Construction Equipment, the lineup of compact excavators features a number of improvements made in recent years, says Joel Powell, senior segment manager, construction. Those features include:

  • short radius offering for improved maneuverability;
  • standard auto-idle for fuel savings and quieter operation;
  • optional angle blades in certain models for improved productivity in fine-grading operations;
  • optional CareTrack monitoring to read machine hours and location from the Volvo CareTrack Web site;
  • a replaceable rubber pad option for the ECR88 model; and
  • an optional Volvo Hydraulic Thumb, installed in the factory or the field, and supported by Volvo.

Volvo CE has recently introduced two new compact excavators, the EC35C and the ECR48C, both with Volvo engines rated at 34.9 net horsepower. The EC35C is a conventional excavator design for exceptional stability with minimal superstructure swing. The ECR48C has a short radius superstructure that turns inside the width of its tracks. Both, however, feature the same large-area operator environment.

Other key features of the two machines include simultaneous control of swing and boom offset movement, which enables faster, more precise performance. Blade float allows for quick-and-easy backfilling, leveling, and finish work. The joystick control lever is equipped with an electronically proportional roller, allowing the operator to accurately adjust hydraulic flow as needed by the attachments.

Potential buyers, Powell says, should consider reliability, serviceability, safety, and transportability, among other factors, such as performance, when choosing a compact excavator. Quality and environmental care are Volvo core values that translate into additional benefits for the end-user.

New From Kubota
In February 2009, Kubota introduced three new excavators: the KX080-3 Super Double Boom 8-ton utility class excavator; the KX121-3 Super Series compact excavator with optional six-in-one hydraulic blade; and the U-17 zero-tail swing compact excavator.

Kubota says the double-boom excavator is the first US machine with this innovative technology. “The expandable boom feature lets operators continue working while repositioning the machine less, resulting in a more productive work site,” says Keith Rohrbacker, Kubota product manager.

The Super Double Boom is designed to bring the bucket more than 3 feet closer to the machine, which makes it easier to hold soil in front of the blade while leveling. Other features include a dumping height of just over 20 feet and a digging depth of slightly more than 15 feet. The Super Double Boom is equipped with a four-cylinder, 70-horsepower Kubota diesel engine and an automatic idling system.

Kubota says its KX121-3 Super Series compact excavator with optional six-in-one blade has extended tilt functions. The blade can be angled 25 degrees and tilted 10 degrees at the same time for greater efficiency when backfilling and leveling. The blade’s float feature puts the finishing touch on backfill projects. The KX121-3 is equipped with a four-cylinder 40.5-horsepower diesel engine.

Kubota’s U17 zero-tail swing compact excavator has a 17-horsepower engine that meets Tier 4 standards. The machine provides increased hydraulic flow for fast, responsive operation and heightened traction force.

Kobelco’s SK210LC
The Kobelco SK210LC Acera Mark 8 Excavator features a new Tier III-certified, 150-horsepower, six-cylinder, direct-injected diesel engine with intercooler turbocharger. This engine features 490 foot-pounds of torque at 1,200 rpm, a 14% increase in torque over previous models. A power-boost feature provides 10% more power on command for increased bucket breakout force without time limitations. The machine also features easy, ground-level servicing of filters, batteries and hydraulics to reduce maintenance time and boost productivity. The SK210LC  has a maximum operating weight of 47,800 pounds and a maximum digging depth of 22 feet. It features an oversized ergonomic cab that delivers complete operational control, progressive hydraulic acceleration and a 360-degree view. The Kobelco line of excavators ranges from 1.7 to 80 metric tons

Case Has News
Case Construction Equipment has announced three new control and performance features to its CX B Series compact excavator line: proportional auxiliary hydraulic control, swing-tower foot-pedal control, and a four-way dozer blade.

Available on the CX27B, the CX31B, the CX36B, and the CX50B, proportional auxiliary hydraulic control allows operators to regulate the hydraulic flow to attachments. That controls the speed of attachments for better handling and manipulation.

The swing-tower foot-pedal control allows for simultaneous function command over the swing tower and house. Operators now can swing the tower and house at the same time, which enables them to quickly position the excavators to dig parallel to buildings and other objects.

A new four-way blade, available on the CX31B, the CX36B, and the CX50B, offers increased productivity in trenching operations. Operators can dig the trench and then angle the blade for quick backfilling without repositioning the machine multiple times.

Case compact excavators are all zero-tailswing configurations. Case compact excavators are equipped with features like a standard feature control pattern selector valve, rubber tracks, pilot-operated hand controls and one-touch engine deceleration that give them operating smoothness and precision.

Gehl and Mustang models of more than 50 horsepower are equipped with an auto-idle feature, which automatically reduces engine speed when full power is not required. “Moving any control lever will immediately raise engine rpm to the set location,” says Brian Rabe, product specialist for Gehl compact excavators. “This new feature reduces exhaust emissions and engine noise while reducing operating costs.”

In recent years Gehl introduced its 503Z, 603, 753Z, and 803 excavator models. All four new excavators are equipped with Yanmar diesel engines that range from 47 to 69 gross horsepower. The new zero-tailswing models, the 503Z and 753Z, both feature operator’s cabs that are larger than the standard models they replace.

The 603 and 803 short tailswing models are designed in a similar manner to the zero-tailswing units, but with an emphasis on increased stability, greater lifting capacity and more engine and hydraulic power than previous models.

Terex markets 11 models of compact excavators ranging from 3,792 pounds up to 27,563 pounds of operating weight and 94 horsepower. The TC35 and the TC35E, for example, have an operating weight of 7,720 pounds with rubber crawlers. The TC35 is equipped with a four-cylinder Mitsubishi engine boasting a net 32.5 horsepower. Gradeability is 60%.

The zero-tail swing, 72-horsepower TC75 Compact Crawler Excavator is able to handle 3.2- to 13.2-cubic-foot bucket capacities, and it is ideal for using a hydraulic hammer. The 92-inch-wide dozer blade is independently controlled from the track drive for uninterrupted operation. And with a simple flip of a switch, operators can change from ISO to SAE controls to suit personal preference. This unit weighs 17,420 pounds and achieves a maximum dig depth of 14 feet, 7 inches and maximum reach of 24 feet, 5 inches.

Komatsu has introduced its PC88MR-8, which has a short swing radius and a Komatsu Tier 3, 65-horsepower diesel engine. This 8-ton class machine bridges the gap between compact and construction-sized units. The engine has 17% more power than the prior model, the PC78MR-6. It also features an increased drawbar pull, faster travel speed, 10% more arm digging force and a significant improvement in dozer blade travel to enhance grading and backfill operations.

Komatsu has also introduced its PC35MR-3 compact excavator with the following features:

  • Spacious operator’s cab
  • Power-angle blade option
  • Standard thumb-mounting bracket and auxiliary hydraulics
  • High-strength X-frame
  • Tilt-forward operator’s station

The PC35MR-3 has a minimum tailswing radius and gets its power from a Komatsu engine with net horsepower of 28.9 horsepower. The direct-injection engine meets EPA emission requirements and is fuel-efficient without sacrificing performance, according to Komatsu.

JCB’s new 5.5-ton mini-excavator is available in both reduced tailswing format as the 8055 RTS, or as a true zero-tailswing model, the 8055 ZTS. This new compact excavator tips the scales at 11,464 pounds and is powered by a 46.5-horsepower diesel engine. JCB offers 10 models of compact excavators ranging up to the Model 8080 with a 13-foot, 10-inch dig depth.

Now would be a good time to go shopping for a compact excavator; dealers are dealing and the competition is stiff among the manufacturers, because there are so many of them.
Eight Features to Look for in a Demo
We asked Bobcat’s Tom Connor, excavator product specialist, what to look for—in terms of the feel of the machine—when you climb aboard a compact excavator for a demonstration. Connor recommends bringing the machine to your job site, if possible. Here’s what he said.Visibility: Compact excavators are often working in tight spots, around sensitive utilities. Be sure to evaluate the machine’s visibility, to the attachment, to the blade, to the sides and rear, and relative to truck loading.

Hydraulic response: One of the most critiqued aspects of a compact excavator is how well, or smoothly, the hydraulic system responds to operator. Evaluate the smoothness of the work group (boom, arm, bucket, etc).

Cycle times: Make an effort to try the machine in the environment you anticipate working in. Evaluate the machine’s cycle times under load. Excavators respond differently as they encounter loads, so make sure the excavator feels right and has adequate cycle times when actually digging.

Ease of entry and exit: There are many aspects, relative to comfort, that an operator should assess before making a decision. The ease with which the operator can get in and out of the machine is particularly important, because operators are likely to get off and back on the excavator frequently during the day.

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Controls: Spend some time on the machine evaluating the layout of the controls. Is their location intuitive, easy to see, and easy to reach? Are they comfortable to grasp? Check the lever effort and the range of motion of all pedals, levers and joysticks.

Operator comfort: It’s important to sit in the machine and take time to evaluate the seat, arm rests, floor space (legroom), and amenities such as whether it’s radio ready, has a 12-V power port, adequate ventilation and so forth.

Attachment readiness: Check to see if the excavator features a quick attach feature, how it works, and if the selling dealer offers attachments for sale and provides attachments for rent.

Dealer support: As with most types of equipment, a buyer should always consider the dealer support in the decision to purchase one machine over another.