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.”
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.”
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).
Source : heavymachineryinfo
“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.”
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.”
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).
Source : heavymachineryinfo
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