Abstract: An improved hydraulic valve assembly comprising a directional valve, such as a spool valve, and a pilot valve of a unique design. The pilot valve comprises a rocker arm, which is controlled by motor means imparting a torque on the rocker arm so as to move a pair of flappers toward and away from associated nozzles controlling pilot pressure to opposite ends of the directional valve. When one of a pair of transducers senses the pressure of hydraulic fluid returning from the directional valve, an opposing torque is imparted to the rocker arm. Equilibrium is achieved when the torques balance each other. The nozzles are provided with annular buffers preventing the nozzles and the flappers from being pressed against each other. The directional valve employs flow restrictors of a unique design wherein annular plates, in a stack, are provided with integral, arcuate, spaced baffles.

Abstract: A pilot valve suited for use as the first stage of a large hydraulic valve system. The pilot valve virtually eliminates the steady state fluid leakage associated with orifice-based prior art systems. A pair of low noise and long life fluid restrictors are employed having flat openings thereto over which a flexible metal strip is disposed. The ends of the strip adjacent each opening are attached to one edge of rolling members whereby they can be rolled progressively off of and over the openings by an electrically driven actuator. In this manner, fluid flow through the two restrictor paths are controlled simultaneously to change the amount of fluid passing therethrough. Taps are provided in each restrictor for taking out the control fluid flow and pressure which are applied to the main valve as the driving means thereto.

Abstract: The method of providing an order of magnitude manufacturing cost reduction in the manufacture of fluid flow restrictors by employing components produced by punch press stamping operations. The flow restrictor is formed of a plurality of annular plates. Half of the plates are punched to form concentric rings of tabs at right angles to one surface thereof. The plates with and without the tabs are alternately stacked concentrically and brazed together to form the fluid flow restrictor having a central core communicating with the exterior surface through a plurality of tortuous paths.

Abstract: A dual-axis magnetometer employs an electromagnet mounted by bender arms within a housing to permit pivotal vibration of the electromagnet with respect to the housing. The electromagnet is driven by an alternating current that causes it to vibrate in the presence of an external magnetic field having a component in a plane perpendicular to the axis of the electromagnet. Output signals are provided at conductors on opposite surfaces of the benders. By observing the relative magnitudes of the output signals and the relationships of their phases with that of the excitation signal, it is possible to determine the direction of that component of the external magnetic field that lies in a plane perpendicular to the electromagnet axis.

Abstract: A method and apparatus for controlling the runout and initial recoil velocity of an artillery piece is disclosed in which variables of barrel elevation and the impulse delivered by a round of ammunition are hydraulically sensed as pressures trapped in actuators which control the flow of fluid to the recoil cylinders of the artillery piece. The system provides for a predetermined constant deceleration of the recoiling barrel assembly regardless of the type or power of the round utilized. When a constant predetermined deceleration is provided, the recoil velocity is uniquely determined and an automatic system is provided for assuring that the loading of the artillery piece always takes place at the same instant of time and that the barrel assembly will have decelerated sufficiently to prevent damage to the snubbing apparatus carried by the artillery piece.

Abstract: A method and apparatus for testing and evaluating the runout and recoil control systems for a gun in which a body having a mass representative of the mass of the moving parts of the gun is accelerated under the control of the runout system under test and then decelerated under the control of the recoil control system under test. During both acceleration and deceleration various conditions such as the position and velocity of the body are measured and recorded.

Abstract: A fluid flow control valve which includes a body formed to define a chamber having inlet, outlet and actuating ports for supplying and receiving fluid to and from external hydraulic machinery to be actuated and including a valve spool formed with several lands and slidably arranged in the chamber for controlling the flow of fluid through the ports, in which the lands and ports are located and arranged so that some of said ports transmit fluid only from said chamber outward while the remainder of the ports transmit fluid only from the ports into the chamber, and which also includes a matrix of restrictors interposed in each of those ports which transmits fluid outward from the chamber, and in which the lands are arranged to control the flow of fluid through only those ports which transmit fluid outward while leaving the flow of fluid into the chamber through the remaining ports unimpeded for all positions of the spool.

Abstract: A fluid actuated gyroscope having a hollow rotor provided with apertures defining nozzles through which compressed fluid within the housing flows to the interior of the rotor before being discharged. This flow causes the rotor to spin up to speed rapidly. Also described is a caging piston which, with its associated apparatus, performs the dual function of providing a passageway for venting the interior of the rotor during spin up and for caging and uncaging the gimbals.

Abstract: A two-stage fluid flow control valve system employing feedback such that the rate of flow of fluid through the load connections follows an input signal very closely over a wide dynamic range. The system employs poppet valves as flow sensors in the return line. The rate of flow of fluid through these sensors is a non-linear function of the pressure thereacross such that the change in pressure drop resulting from a given displacement from a set flow rate is greater at low ranges of flow than at high ranges. The result is closer control at low rates of flow where such control is normally more difficult to achieve.

Abstract: A fluid .[.Flow Restrictor.]. .Iadd.flow restrictor .Iaddend.especially suitable for reducing the pressure of gases or liquids is described. The restrictor comprises a series of rows of baffles placed in the path of fluid flow, with the baffles in succeeding rows staggered with respect to those in adjacent rows so that as the fluid flows, it is constrained to change its direction repeatedly. The restrictor is preferably constructed with an increasing cross sectional area along the direction of flow. One suitable physical construction comprises a plurality of thin circular plates with a central bore, arranged in a stack. Each plate has a baffle pattern formed on one or both sides, for example, by etching. Fluid flow is from the central bore, between adjacent plates, to the circumference of the stack.