Two hoses and a pin
To make it easy, Pentin Paja developed a stroke harvester that would be as simple to use and install as possible. By cutting off everything extra, Naarva S23 weighs only 230 kg and uses only 4 hydraulic cylinders. The required lifting capacity of the boom is only 25 kNm. Switch between loading grapple and Naarva S23 is easy, connect two hoses and remove one pin.
New simple guillotine was designed for Naarva S23. There is only one grip arm and a cutting blade. Shape of the blade ensures that the cutting is done against a J-shaped counterpiece. Cutting does not strain the body because guillotine is attached to the head with a slide. Maximum cutting diameter is 23 cm. Guillotine can be equipped with firewood wedges, which are installed in the cutting blade. This simple attachment cuts and splits half meter firewood directly after felling.
Stroke harvester is operated with grapple open/close buttons. Close-button closes the grips and after a pressure limit is reached, the stroke feeding will start. After the stroke has reached its maximum position (50 cm), you can press grapple open-button and the stroke cylinder will reverse. This cycle will be repeated until the wanted length is reached. Then you can cut the tree by holding the close-button. When the stroke cylinder has reached its maximum position and a pressure limit is reached, the oil flow is guided to the cutting cylinder and tree is cut.
Mechanically locked tilt
When delimbing head is not out and grips are open, S23 will stay upright because of center of gravity. When a tree is grabbed in upright position, S23 tries to start delimbing, but instead of delimbing the head is locked against the tilt body. When grip is released, delimbing head will unlock.This enables moving of small trees before delimbing.
Firewood directly after felling
Cutting blade can be mounted with splitting wedges to make 25-50 cm firewood directly after felling. Wedges are easy to mount and dismount with 3 bolts. Logistics improve significantly.
To increase productivity of Naarva S23 even more we developed a Naarva firewood rack. Simple, durable rack for a firewood bag that is mounted to a tractor. Cut and split trees directly after felling straight into a firewood bag. Naarva firewood rack has standard CAT 2 or CAT 3 coupling for three-point linkage of a tractor.
This is the most straight-forward firewood production process in the world. In bags the firewood dries up quickly and bags are easy to handle. Immediately after felling, you have firewood ready for sale.
Naarva S23 is sold with a very reasonable price because of simple design and low manufacturing costs. It has been the most successful product of Pentin Paja Oy yet.