GB1509929A - Vehicle having a hydraulic lifting and lowering device for a working implement - Google Patents

Abstract

1509929 Hydraulic lifting and lowering device for harvesters AEBI & CO AG MASCHINENFABRIK 8 July 1975 [12 July 1974] 28622/75 Heading A1F A combine harvester has a hydraulic implement lifting and lowering device comprising an accumulator 13 connected to a lifting cylinder 3 of the implement I via a stop valve 12, only openable in a relieving position in which a limited force acts on the implement when the lifting cylinder is in lifting and holding conditions, and to the return conduit 8 of the sump 10 via a pressure limiting valve 14. The control lever 15 moves in a U-shaped guide to operate a three position reversing valve 14. The lever is biased by spring 23 and moves in the left-hand shank of guide 18 to attain lifting, holding and lowering positions. The relieving position is attained by moving lever 15 into the right hand shank since a switch 24 is depressed by a plate 22 and the valve 12 is electrically opened to connect the accumulator 13 to the cylinder 3. With lever 15 in the bottom right-hand position, the accumulator 13 is charged via conduits 6, 4 by pump 7, but moving lever 15 upwards closes off conduits 4, 6 and 8 in valve 5. For prolonged operation in the relieving position, the accumulator can be recharged when the pressure falls below a selected pressure by incorporating an electric switch 26 in the circuit of a pressure switch 27 and charge valve 28 located in the conduit 8. Electric switch 24 may be replaced by mechanical switching means.