Abstract: A control apparatus is disclosed for permitting simultaneous actuation of a plurality of fluid motors whose combined flow capacity exceeds the available flow rate. The plurality of fluid motors are actuated by a corresponding plurality of open center, pressure-compensated, pneumatically actuated control valves which are connected in series flow arrangement with a fluid supply having a fixed minimum flow output and a maximum flow rate output. A device is provided to sense the rate of flow for hydraulic fluid exhausting from the series of control valves. The rate of flow sensing device controls a pneumatic pressure regulator that provides a corresponding pressure change in the pneumatic supply pressure provided to a plurality of control valves.

Abstract: An amplifying valve having an axially slidable valve spool to normally communicate a service port with a reservoir port, but which is movable to an operative position by a diaphragm type actuator activatable by air at substantially low but different selected pressures at the command of a pilot valve. In its operative position, the spool communicates the service port with a supply port for oil at high pressure. The pressure of oil at the service port is translated into a force on the spool to counteract that which is imposed thereon by the diaphragm actuator, so that service port pressure will always be substantially greater than but proportional to air pressure on the diaphragm.