Abstract: A two stage valve assembly responsive to signals from a control system for supplying pressurized fluid to two load lines. The first stage includes a motor that directs pressurized fluid from a jet pipe toward a receiver assembly having two receiver ports and a bleedoff area disposed between and separating the receiver ports. The second stage assembly includes two spool/sleeve assemblies that control the flow of pressurized fluid to and from the two load lines. A drain line from the receiver assembly includes a pressure relief valve, which insures that both spool/sleeve assemblies will be servo-controlled at all times. Cartridges may be inserted in the spool/sleeve assemblies to linearize the relationship between input current from the control system and the output force of an unequal area actuator connected to the load lines.

Abstract: A quantity of circuit chips are slidingly received in end to end relation in an elongated receptacle or "stick". The required number of such sticks are located in parallel groups at each side of a substrate mounted on an adjustable support. A pair of vacuum heads reciprocate along a path transversely of the substrate a fixed amount from a first extreme with the vacuum head located immediately over the endmost chip in a stick, to a second extreme which is a constant distance from the first position and lying over the substrate. The substrate is positioned to the proper x-y location such that when the transfer mechanism moves a chip to the position over the substrate, it will be properly located at the correct part of the substrate circuit. The sticks are indexable as needed to a position presenting the endmost chip of the selected stick underneath the outer extreme of the movement of the vacuum head. Control apparatus positions the substrate in any desired series of x-y locations.