This paper describes a new model loader, it's systems and how their melding produced a much more efficient and productive machine. It discusses in some detail the selected hydraulic system, a closed center load sensing system with both the traditional flow control characteristics and the newer pressure control characteristics, which were utilized to achieve superior swing performance.
A new world class loader to bridge the gap between the company's current 88.9 kN (20,000 lb.) lift loader and it's 133.3 kN (30,000 lb.) loader was needed. During customer visits and surveys as to their wants and needs in a new machine, the following items kept surfacing:
Longer booms (log sorting and slashing or scrap handling)
Faster boom action (balanced with swing speed)
Greater swing torque (drag loading and delimbing)
Improved fuel economy and overall performance
Operator comfort and safety
Better visibility for the operator
Ease of service and no hydraulic leaks
These customer inputs were not particularly startling or unreasonable and did help in keeping the program focused on major area's of interest. The new design was accomplished for a truck and trailer mounted loader (See Figure I).
Part of the new loader's specifications are shown below:
Boom length of 9.75 m (32 ft.).
Boom lift of 121.4 kN at 3.05 m (27318 lbs. at 10 ft.).
Swing torque of 46546 Nm (34360 lb. ft.).
Hydraulic system pressure of 20.69 mPa (3000 psi).