Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/917937
EquipmentWorld.com | December 2017 23 as the cylinder is extended. "Load-sensing hydraulics combined with regeneration provide speed, precision and power to improve cycle time and productivity," says Jeff Jacobsmeyer, Kubota product manager for exca- vators, wheel loaders and backhoe loaders. Volvo also uses regenera- tion. John Comrie, prod- uct manager for compact excavators and compact wheel loaders, says it and other sophisticated hydraulic design strategies allowed the company to retain hydrau- lic performance, even on machines with horsepower dropped from 34 to 25 for emissions compliance. "Breakout and lift are equal to or greater than prede- cessor machines," he says. Load-sensing piston pumps and proportional auxiliary hydraulics also maximize hydraulic performance and control, allowing operators to do fine work even with the bucket. Multiple pumps were once common; a machine could have three or more. While some compact excavators still run multiple pumps – Takeuchi has four in most models – there's a move toward single pumps. Im- proved pump performance and sophisticated flow con- trol make this possible. "Customers sometimes ask if there's a loss of perfor- mance with single pumps," says Connor, "especially with high-demand attachments such as flail mowers, which are becoming increasingly popular." Connor says the concerns are unwarranted, that modern single-pump systems, paired with appro- priate main control valves, can outperform older multi- pump systems even in high- demand applications. Hyundai has nine models of 9A Series compact excava- The Hyundai R30Z-9AK features centralized lubrication and extended preventive-maintenance intervals. Long-life hydraulic oil provides 5,000 hours of service. Hydraulic filter changes come at 1,000 hours, and bushings get lubed every 250 hours. Power is from a Kubota D1305 Tier 4 Final diesel rated at 23.2 horsepower. Among the features from larger machines making it into the JCB 45Z-I are steel bodywork, four-plate dipper construction and 100 percent graphite-impregnated bushings on the dig end. Compared to the previous 8045 ZTS, this new machine has a longer main boom and shorter dipper arm, yielding dump heights up to 13 feet. The 45Z-I has a transport weight of 9,700 pounds. G eorge Lumpkins has been in the industry for decades. He is now the general manager of marketing and product development at Kobelco. He offers these observations based on his wealth of knowledge and experience: • Never operate any excavator with the travel motors in front and under the cab. There are a number of safety considerations, foremost of which is that travel motors are heavy and having them in the front will upset the primary balance of the machine. • Thumbs are common in North America but rarely used in other parts of the world. • North and South American markets are unique in that excavators are used to lift items around the jobsite. Standard and optional counterweights are offered that increase stability for these tasks. • Counterweights are useful to balance the weight of attachments, including thumbs and quick couplers. Regardless of the intent, never use a counterweight that exceeds the manufacturer's maximum counter- weight recommendation. • Compact excavators have taken over many applications performed by backhoe loaders. Pattern changers ensure operators can use the control pattern they prefer. • When running a hammer, set the return pressure to its lowest value for optimal power and durability and reduced heat. Observations from the guru