GB1414061A - Hydraulic power generating arrangement - Google Patents

Abstract

1414061 Pump driving arrangements; gear-pumps A D TOOTH and L J FORDHAM 24 May 1973 [2 June 1972 14 Nov 1972] 24807/73 Headings F1A and F1F [Also in Division F2] A pump, e.g. for operating a vehicle tipping jack hydraulic system, is driven via a clutch which is normally biased into its disengaged position and is initially engaged, e.g. by a mechanical linkage, to start the pump, and is held engaged by hydraulic means energized by the pump output so long as the hydraulic system is pressurized, means being provided to depressurize the system. In Fig. 4, a gear-pump 52 has a shaft 53 driven by a pulley 67 when the pulley is moved to the right to engage a clutch plate 65 keyed to shaft 53, the pulley being moved initially by mechanical means, and then held in engagement by pump output pressure acting on piston 85 via passage 88. A spring 68 disengages the clutch when the pump system is depressurized. In Fig. 3 (not shown), the gear-pump assembly is axially movable in its casing by its output pressure and moves the drive-shaft and clutch plate to engage the pulley. In Fig. 1 (not shown), the whole pump (1) is movable to engage a drive flange (6) on its shaft with a clutch plate (22), and at the same time causing disengagement of the clutch plate from a pulley (10), e.g. connected to an engine auxiliary.. In Fig. 2 (not shown), an annular piston (39) acts to move a spring-loaded pulley (34) against a clutch plate (31). In Fig. 5, the pump 94 supplies actuating liquid from a sump 91 to a jack 89 via a control valve 93. Valve 93, Fig. 6, comprises a threaded bobbin 100 which is movable to connect the pump output, at port 109, to the jack, at port 110, via bobbin passage 108 and check-valve 105. When the jack piston has reached its required position, bobbin 100 is moved to the right to connect pump output port 109 to sump port 111, check-valve 105 then closing to lock the jack piston in position, and due to depressurizing of the pump output by its connection to the sump, clutch 96 disengages to stop the pump; such depressurizing also may be effected by valve 112. To effect return of the jack piston, bobbin 100 is moved further to the right to lift valve 105 off its seat, thereby connecting the jack to the sump via bobbin passage 108 and port 111. A pressure relief valve 92 is provided.