HARVESTER HEADS
hydraulics. The grapple can be equipped with a radio control system, which makes installation really easy. In addition, Naarva EF28 is cost effective to operate, since it requires only about half of the power needed by harvester heads with chain cutting. Despite this, the grapple is ideally suited to small wood handling and performs reliably in all conditions. EF28 can be installed in harvesters, excavators (14-20 t), and combi machines.
At Skogselmia 2011 in Sweden KESLA introduced a completely new harvester head model 25RH mkII. The head was developed, proceeding from the development needs and feedback from the users of more than 400 delivered 25RH units. New solutions to the frame, delimbing knives, shafts and bearings are targeted at even better durability and lower maintenance need even in the most demanding operating conditions. As the power of carriage machines is continuously increased, the efficiency ratio of hydraulics has been in special focus. The new, wider
valve system contributes to clearly higher feeding power and speed while fuel consumption becomes significantly lower. With the new valve design, the ease of maintenance of the harvester head has also achieved a new level.
Finnish forest machine manufacturer Logset will launch a new series of harvesting heads, Logset Titan heads, at the beginning of 2012. The heads have been developed and tested with forest machine contractors from all over the world.
The new chassis design allows fluent, low friction stem feeding therefore reducing engine load and improving fuel efficiency. All sections are welded to form a one-piece chassis.
reducing component stress and fuel consumption. This feed system also allows the knives to be opened during feeding if necessary. The rollers have been mounted on the same line to combine the best grip and least friction from the three wheels. Efficiency is a key figure regarding Logset’s
New harvester head model 25RH mkII
Mountings, pivots etc are then machined after the welding has taken place, which ensures a reliable frame throughout. All chassis- to-stem contact surfaces are manufactured from wear resistant steel. The rigid tilt has two strong cylinders to keep the tilt in the correct position and allows a large reverse tilt angle. The tilt geometry promotes excellent weight balance allowing increased productivity. With all Logset Titan heads, the feeding rollers carry part of the tree weight while pressing the stem against the back roller. This greatly reduces stem-to- chassis friction and also allows lower pressures at the delimbing knives during feeding therefore further
Titan head design. The geometry of the delimbing knives allows perfect delimbing on all diameters. The pressure on the knives is controlled proportionally according to the tree diameter optimising the delimbing result. The chassis-mounted fixed-back knife will improve pre-felling and reverse-feed delimbing. All new heads have a hydraulically controlled measuring wheel allowing the measuring wheel to be retracted when needed. This will lengthen the life time of the measuring wheel and its arm
Logset TH45 felling
AUGUST/SEPTEMBER 2011 | International Forest Industries 45
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