SE358803

1312627 Implement power life systems DEERE & CO 28 April 1970 [28 April 1969] 20354/70 Heading A1P For use in a tractor/implement combination where the tractor has pivotally mounted trailing draft links and a hydraulic power life system, an implement has adjustable life assist wheels 122 and hydraulic motors 136, 138 mounted on the implement frame 108, 110 and operatively connected to the lift assist wheels to raise and lower the implement. The motors are connected in series with each other and, when the implement is mounted on the tractor, by means of three point hitch for example, the hydraulic motors are also connected in series with the main hydraulic motor 16 of the tractor power life system. The frame may be rigid or comprise a rigid central portion 88 with two pivotally mounted outrigger portions 108, 110. A further lift assist wheel may be provided rearwardly and centrally of the frame 88 (Figs. 4, 5 not shown). A conventional control valve 38 may be operated in three ways by a manual control lever 40, by a position responsive control connected to lift arms 28 and by a draft load responsive control connected to draw links 30. Fluid is supplied by a variable displacement pump 34 and the double-acting motors 136, 138 and motor 16 have progressively smaller piston diameters as shown in Fig. 3 so that the rods 144, 22 move the same distance. Pressure relief valves 68 and by-pass valves 152 are also provided. Auxiliary control valves 70, 72 are used, when travelling over uneven ground, to spontaneously raise or lower the centre frame 88 alone (by valve 70) or centre frame and outrigger frames together (by valve 72).