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Interforst 2014: Compact hydraulics solution for harvester power units
7/26/2014 |
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Less space required, lower weight - HAWE Hydraulik's valve block for harvester power units
HAWE Hydraulik SE, Munich, has developed a space-saving valve block for the hydraulic functions of harvester power units. The valves are made from steel with compact dimension to keep their weight relatively low. At 47 kilograms the valve block is around 50% lighter than standard solutions currently on the market. The lower the total weight of the harvester power unit the further the crane's arm can be extracted and the heavier the tree trunks the driver can move.
The valves to actuate the feed rollers of the harvester power unit are designed for a volume flow of 400 lpm so that tree trunks can be moved at great speed. These feed rollers can be actuated together or individually. The contact pressure of the delimbing knives can be set electro-proportionally and remains constant throughout the entire processing phase. This way the knives follow exactly the tree trunks contours and cut off the branches at the defined height. Due to the steel construction the maximum pressure can be as high as 420 bar making the valves impervious against pressure spikes, which can occur when branches are cut off the trunks or when the trees are felled or turned around.
A pressure compensator controls the chainsaw's velocity irrespective of the loads, so that the torque of the saw remains constant. Thus, the saw does not get stuck in the wood, does not wear down so easily and the cut is even and smooth. The maximum volume flow for the chain saw function is 250 lpm.
The load-sensing principle of the PSL proportional directional spool valve enables a jerk-free turning and tilting of the power unit. When the operator additionally activates the floating position, the power unit is suspended freely from the crane and can be comfortably transported and placed into position.
The pressure required for the activation of the additional functions, such as holding down the metering wheel, lubricating the chain or color coding tree trunks, requires less than the entire system. HAWE Hydraulik therefore uses individually adjustable pressure control valves, which can be preset or manually set by the driver. |
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Related Exhibition:
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Interforst 2014
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Trade Fair for Forestry and Forest Technology
7/16/2014 - 7/20/2014
Venue: Messe München, Munich, Germany
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