The Mycorrhizal Requirement of the South African Forest Nursery

To achieve smoother and faster handling of timber has always been an important aim for designers of hydraulic loaders on forestry vehicles. Such loaders normally have “open-centre” hydraulic valve assemblies, in which the valves are open and oil flows freely through them when their control levers are in the neutral position.

Control systems of this kind require skilled manipulation if even three of the loader's six basic movements are to be operated together, and the continuous physical and mental strain on the operator is high. Yet timber handling takes up a major part of every forestry vehicle's life.

The article describes a new load-sensing and pressure-compensated system with proportional control—the “ERGO” system—which enables more loader movements to be handled simultaneously, resulting in greater ease and speed of handling, less operator fatigue and a closer bond between man and machine.