GB1347023A - Hydraulic systems - Google Patents

Abstract

1347023 Hydraulic motor control circuits JOSEF HAAMANN FREUDENBERGER WINDENUND HEBEZEUGFABRIK 20 April 1971 [21 April 1970] 10144/71 Heading F1P In a gantry-type load lifting vehicle formed of two gantries joined together by girder systems and having a retractable swivel arm G only one of which is shown carrying a wheel R mounted at the foot of each gantry post Pf so that each wheel R can be swung out to the travelling position to raise its associated gantry off the ground, a supply of hydraulic fluid for driving (a) a plurality of load lifting members I..IV (b) a wheel driving motor 60, (c) a vehicle steering motor 60, (d) a vehicle steering motor 50 and (e) a swivel arm operating motor 37..40 comprises a pump P having as many separate outlets 1 to 4 as there are load-raising members and each leading to a two-position selector valve 5..8 which in the positions shown connect each pump outlet 1..4 separately to an associated load raising member through pressure lines 14<SP>1</SP> ..14<SP>4</SP> and which valves 5..7 when in their other position connect pump outlets 1 to 3 collectively through lines 31..33 to the wheel-driving motor 60, whilst valve 8 when in its other position connects pump outlet 4 either to the steering motor 50 or to motors 37..40 according to the setting of a distributing valve 44. To retract say the loading lifting rod 25 of say member II, a distributing valve 16 is moved so that pressure line 14<SP>2</SP> is connected through a pilot operated check valve 19 to the lower cylinder space 20. During rod extension the valve 19 is held open by pressure from an auxiliary pump 27 in a line 28' and this line pressure may be used to adjust the position of rod 25 by means of an adjacent valve 29. To transport the gantry each valve 5..8 is moved to its other position, a valve 44 in outlet 34 of valve 8 is moved to the left whereby each of the four arms G is swung down by an associated motor 37 so that wheels R are grounded and posts Pf raised. Valve 44 is then moved back to the position shown to supply a steering valve 35 whilst a steering valve 52 in the combined output lines 31-33 serves to control the wheeldriving motor 60. In a modification the output of all four valves 5..8 may be collected and fed to the driving motor 60 and the auxiliary pump may also be fed to the steering motor 50 and the motors 37.. 40.