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APPLICATION HARVESTER

Harvesters are automated wood harvesting machines that have been used since the
beginning of the 1980s for the felling and preparing of trees without heavy manual
labour. The so-called harvester head, at the front of the machine's boom, is responsible
for marking, gripping and felling the trees. These are then fully automatically delimbed,
debarked and cut to length for removal in accordance with the specifications.

FUNCTION
An automated wood harvesting machine is usually used in
rough terrain, far away from modern civilization. It is exposed
to extreme weather conditions in the forests and is designed
for temperatures ranging from very warm to extremely cold.
The wood harvesting head on the boom of the machine is
very exposed and therefore constructed extremely solid.
Nevertheless, it must be possible to control the many moving
components with high precision and reliability.
The dimensions and execution of the harvester head and the
hydraulic components used in it are largely determined by
the size of the trunk and the type of wood to be harvested.
The hydraulic system is used to control the feed rolls or feed
rollers, the measuring devices, the chain saw drive including
chain tensioner, the chain lubrication, the sword feed as well
as the delimbing knives and the colour marking unit. Thanks
to high precision, robustness and reliability, proportional or
mechanically adjustable pressure reducing valves and flow
control valves from Wandfluh have been used for many years
for this demanding work.

COMPONENTS
On a harvester, common standard valves are used, such as the
MVPPU10 pressure relief valve to control the feed roll and the
delimbing knife, or the BDIPM22 pressure reducing valve to
control the saw-bar. On the other hand, numerous customer-
specific special valves are adapted to the respective harvester
head, for example for pilot control.

SPECIALITIES
• Pressure relief valves with fast response time and low hysteresis
• Pressure reducing valve with fast response time for pressure build-up and unloading
• Valves with high contamination and water resistance
• Special solenoid coils for use in warm climatic conditions

WANDFLUH MOBILE | APPLICATION | HARVESTER | PAGE 5