GB1202471A - A stabilizing apparatus for vehicles provided with a load handling apparatus - Google Patents

Abstract

1,202,471. Stabilizing apparatus. HYDRAULISKA INDUSTRI A.B. 17 May, 1968, No. 23518/68. Heading B7J. In a vehicle having an hydraulically operated load handling apparatus 3, and provided with supporting legs 23, 24 on each side of the vehicle hydraulically lowerable to the ground, the pressure fluid for the load handling apparatus and for the supporting legs being supplied by the same fluid pump 16, a control valve 31 is connected between the pump 16 and an operating valve 10 for the load handling apparatus so that fluid pressure is transmitted to the valve 10 only when hydraulic pressure is supplied to the supporting legs 23, 24. Piston and cylinder devices 5, 6, 11, 12, for controlling the load handling apparatus 3 are connected via conduits 8, 9, 13, 14 to the operating valve 10. The supporting legs 23, 24 are each operated by a piston and cylinder device 21, 19 and 22, 20, supplied with pressure fluid through conduits 27, 28 and valves 29, 30. The control valve 31 comprises a spool valve 32 having a spool 33, and two cylinders 34, 35 coaxial with the spool 33 having a common piston 36, A bracket 46 prevents relative movement of cylinders 32 and 35, but cylinder 34 is slidable along the axis of the pistons, being urged to the left by the spring 51. A sleeve 40 attached to the cylinder 34 is connected to the spool 33 by means of a driving pin which passes through enlarged holes 44 in the sleeve 40 allowing some play. Movement of the piston 36 and cylinder 34 being limited by the rings 49, 50 on the piston. Conduits 64, 65 connect the cylinders 34, 35 to the cylinders 19, 20 of the supporting legs. The spool valve 32 has three annular grooves 56, 57, 58 on its inner surface and the piston 33 has a circumferential groove 59 of equal or slightly greater length than the spacing of the grooves, groove 57 being connected to the fluid pump 16, groove 58 to the operating valve, and groove 56 providing a return path for fluid to a reservoir 15 via a throttling valve 62. When the pump is operated the pressure buildup due to the throttling valve 62 is sufficient in the conduits 27, 28, if valve 29 is open, to lower leg 23. Fluid pressure will be transmitted via conduit 64 to cylinder 34, moving it to the right against the spring 51. No movement is transmitted to spool 33 due to the lost motion in the connection of sleeve 40. If valve 30 is now opened, leg 24 will be lowered and fluid pressure transmitted to cylinder 35 forcing the piston 36 and hence cylinder 34 to the right, causing spool 33 to move to connect grooves 57 and 58, thus allowing pressure fluid to reach the operating valve 10.