| 摘要 |
<p>A ground-preparation device for tree-planting, comprises an arm (2) adjustably carrying a toothed rotary tool (1) and pivoted to a mounting (3) on a tractor about horizontal and vertical pivots (10, 11). The tool is held resiliently in a selected position in the horizontal plane about the pivot (11) by means of hydraulic rams (12, 13) adjusted from the driver's seat. Should the tool meet an obstacle, the arm pivots against the action of one of the rams. The tool is rotatably mounted in a housing itself rotatably adjustable on a pivot (6) on the arm (2). The pivot (6) carries a lever (7) connected to a spring-loaded arm (9).</p> |
