| 摘要 |
A hydraulic system for a tree-felling unit comprises valve means 6,8 and connecting lines 11,13 for feeding hydraulic fluid through the said valve means to and from hydraulic working devices 2,3,4,5 for the members for tilting of the unit, for rotation of the unit, for gripping of the tree and for cross-cutting of the tree. The hydraulic working devices 2,3,4,5, which are driven in sequence during the work cycle, are connected in pairs to the same valve means. The control devices 2,3 for the tree-felling unit are connected to separate valve means 6,8 and the processor devices 4,5 for the tree are connected to separate valve means 6,8. The flow of the hydraulic fluid to the working devices 3,5 is regulated by a control valve 17, which is driven by the pressure in the hydraulic fluid lines belonging to the unit. <IMAGE> |
