Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/917937
December 2017 | EquipmentWorld.com 26 tors. The newest, the R30Z-9AK, has a list of more than a dozen improvements to its hydraulic system. Some, such as switchable control patterns (excavator/ISO and backhoe/SAE) are industry standards. Some enhance the operator experience, such as a circuit damper on the travel pedal to reduce shock load when starting and stopping in either forward or reverse. There's also a selector valve to choose single- or double-acting operation of the auxiliary circuit. At least one feature simplifies maintenance; the swing motor is lubricated entirely by hydraulic oil, allowing the motor to be ser- viced when the hydraulic system is serviced. Controlling flow and pressure and the ability to choose between one- and two-way flow make it easier to match attachments to a machine and to receive peak performance from those attachments. But resetting the variables every time there's an attachment change is time-consuming, so manufacturers offer program- mable settings that can be matched to an attachment and stored in memory. Kubota, for example, offers the ability to program and store information for up to five attachments. Both the programming and the selection from among the stored settings are done through the in-cab monitor. A hammer circuit and selectable two-way hydrau- lics are standard on all six new models of compact excavators from New Holland. In addition, the largest models, the E57C and E60C, feature separate circuits with optional second auxiliary two-way circuits and an optional hydraulic quick-attach provision. The six models represent a doubling of the number of com- pact excavators offered by New Holland. machine matters | continued Fuel efficiency is improved on the Komatsu PC55MR-5 compared to previous models through a Tier 4 Final engine, auto-idle shutdown and economy mode. A high- strength, X-track frame resists dirt and debris buildup. Standard Komtrax telematics provide operating data, in- cluding location, hours and status of the Komatsu diesel particulate filter. Powered by a Yanmar engine rated at 37.4 net horsepower, the Kobelco SK55SRX has two variable-displacement hydrau- lic pumps and two gear pumps, one of which is allocated for pilot circuits. Maximum digging depth is 12 feet, 10 inches, and maximum dump height is 14 feet, 3 inches. The short-swing-radius Volvo ECR40D is compatible with a range of hydraulic attachments, including thumbs, breakers and tiltable ditching buckets. Both mechanical and hydraulic pin-grabber quick couples are available. Power is provided by a Volvo D1.7A engine rated at 24.8 gross horsepower. Maximum auxiliary flow is 17.2 gallons per minute.