PERFECCIONAMIENTOS INTRODUCIDOS EN LOS MECANISMOS HIDRAULI- COS DE ELEVACION PARA IMPLEMENTOS O APEROS ACOPLADOS SOBRE TODO A TRACTORES AGRICOLAS

摘要

An improvement in apparatus for lifting an agricultural implement carried by a tractor provides for automatic rapid level adjustment of the implement relative to the terrain under control of a valve system which comprises a regulator valve controlling inlet flow to the pump responsive to a comparator valve carried by the implement. A continuous throtted flow from the regulating valve to the comparator valve is maintained at constant pressure tending to open a valve in the comparator while a sensor or feeler contacting the ground serves to effect a greater or lesser opposing force. A servo valve is provided which effects a back pressure acting together with feeler actuation. An equilibrium position of the valve determines the level to which the implement is changed, holding it constant on level ground until the feeler is actuated by encountering a rise or fall in the terrain. The construction provides for varying the elevation of an implement by either raising it or lowering it to meet rise or fall of terrain.