Logging equipment has to be tough and reliable to deliver productivity under demanding conditions. Hydraulics are used extensively to meet these requirements in the new Komatsu PC290LL-11, the latest addition to the company’s line of log loaders. These machines sort logs that have been cut, stack them into piles, and load them onto trucks.

Powered by a 196-hp Komatsu SAA6D107E-3 diesel engine that meets stringent EPA Tier 4 standards, the machine is available in either a live-heel log loader configuration with a 40-ft. reach or a road builder configuration with a 34-ft. reach. Log loader and roadbuilder operating weights are 40,700 kg (89,730) lb and 37,300 kg (82,240) lb, respectively.

Tandem Pumps Power Multiple Functions
The heart of the machine’s hydraulic system contains two variable-displacement piston pumps. Pump displacement has been increased over previous models to provide greater flow output and ensure operation at the most efficient engine speed. Each pump has a maximum output of 65 gpm (245 lpm) for a total maximum flow of 490 lpm (130 gpm).

The pumps’ displacement is controlled by load-sensing pressure, in which the load-induced pressure is sensed, and pump flow is adjusted by appropriate valves to maintain a constant pressure drop—and, therefore, constant flow. In addition, electronic proportional control solenoids provide load-sensing and horsepower control.

Each of the log loader’s tracks is driven by a variable-displacement piston motor powered by each main pump. Each hydraulic motor has a maximum displacement of 182.4 cm3/rev (11.13 in3/rev) and drives a planetary gearbox, which reduces rotational speed and increase torque. The final drive generates 64,250 lb of drawbar pull. By pairing the variable-displacement motors and pumps, Komatsu’s machines can achieve three travel speeds (low, medium, and high) instead of the more common two. This is accomplished by changing motor displacement and controlling pump displacement electronically.

Read more: Log Loader Stacked with Hydraulics