GB1381832A - Hydraulic control device for loadindependent flow control - Google Patents

Abstract

1381832 Valves ROBERT BOSCH GmbH 29 March 1973 [23 June 1972] 15194/73 Heading F2V The flow to a load 31 is reversed by movement of a spool valve 13 and is maintained constant by a fluid actuated valve 33 having its left hand face connected to the supply pressure in a passage 21 and its right hand face to a line 52 or 53 supplying fluid to the load. The valve 33 bypasses fluid from the passage 21 to a return line 23 and has its right hand face isolated from the line 52 or 53 by lands 50, 51 when the spool returns to neutral position. A check valve 32 prevents fluid being returned by the load to the supply while passages 25, 26 permit free circulation of fluid between the supply and return lines when the spool is in its neutral position. Further passages 22, 24 may be connected to the supply and return ports of a further spool providing independent control of a second load without the flow control feature. Alternatively, the two spools may be connected so that operation of the first prevents fluid from being supplied to the second.