Hydraulic switching arrangement for lopping machines

摘要

The invention relates to a hydraulic switching arrangement for lopping machines and units, the movable lopping cutters of which are pressed on the tree trunk by hydraulic working cylinders. The aim of the invention is, while maintaining a good lopping quality, to lower the drive power required for the lopping procedure. It is the object of the invention to lower the advancement force required for pulling the tree trunk through the cutter system in that the contact-pressure force of the lopping cutters in the branch-free trunk regions is to be lower than in the case of direct cut-off of the branches, it being intended to achieve, at the same time, a mutually independent adjustability of the two contact-pressure-force stages. This is achieved in that a pressure control valve and a non-return valve, connected in parallel thereto, are arranged in the discharge line of the hydraulic working cylinders coupled to the movable lopping cutters. <IMAGE>