Abstract: A compensator for use with a hydraulic control valve connected to a source of high fluid pressure provides the functions of a low pressure return line accumulator and controllable check valve. A spring loaded piston (66) in a housing (64) has a working face exposed to fluid pressure downstream of the power control unit (10). A poppet valve (80) movable in a bore (78) on the axis of the piston is spring loaded against a seat (82) in the return line (40, 42) to interrupt flow between the downstream side of the power control unit (10) and the return side of the fluid pressure source. When normal return line pressure is sensed, the piston (66) moves against its spring (68) to permit the housing (64) to be substantially filled with fluid. Further increases in fluid pressure cause the piston (66) to contact and open the poppet (80) and permit flow to the return side (42) of the fluid pressure source.

Abstract: A cable wiper assembly for airborne sonar includes a housing suspended from a hoist used to rapidly raise and lower a sonar transducer at the end of a cable. The wiper assembly is interposed ahead of the cable-directing sheaves forming part of the hoist to strip away the sea water which adheres to the cable as it is pulled from the ocean. The housing includes a plurality of wiper stages, each of which consists of a washer-like rubber wiper whose internal diameter is just slightly smaller than the cable diameter and a spacer having substantial thickness interposed between wipers with a centrally located well on one side and a flat surface on the other. Radial passageways at the bottom of the wells direct water stripped away by the wipers to the outside of the spacers. The housing includes means clamping the wipers and spacers together and also radial ports for discharging the water flowing away from the spacers.

Abstract: Multiple path means for a fluid flow control device is shown in connection with a typical spool type servo valve. The multiple path means consists of a stack of washer-like elements or disks which cooperate to define a number of finely divided flow paths across the stack in which flow is forced through a series of alternating chambers and orifices with measured pressure drops across the orifices. Since many servo valves have comparatively short travel and since both control and wear problems tend to be most serious near null, it is desirable to minimize abrupt step flow gains around null.In the present disclosure individual disks, at least at the ends of the stack, are made comparatively thin such that the thickness of two or more disks may be required to provide a normal opening width into the stack.

Abstract: Multiple path means for a fluid flow control device is shown in connection with a typical spool type servo valve and a relief valve. The multiple path means consists of a stack of washer-like elements or disks which cooperate to define a number of finely divided flow paths across a stack of disks. To provide a configuration which is very economical of space, the disks are arranged such that the flow path turns back and forth through different planes. Groups of flow paths are defined by a number of groups of perforated disks confined between the imperforate disks. Two perforated disks having patterns of openings are positioned on opposite sides of a similar disk having a pattern of small orifices.

Abstract: A payout sheave for a cable connecting an underwater transducer array or instrumentation package to processing and display equipment directs the cable as it is payed out and in toward a reel and level wind mechanism carried in a platform vehicle such as a boat or helicopter. The supporting frame for the sheave includes a cross member supported along a first axis in bearings in the frame and which carries additional bearings at its center. These center bearings carry an intermediate support structure which is rotatable thereon along a second axis perpendicular to the axis of the cross member. This intermediate support structure carries a pair of journals and bearings oriented along a third axis perpendicular to each of the first and second axes. A fork member is attached to the intermediate support structure through the bearings, and the sheave is carried in the bifurcated section of this member and thus, in effect, is gimbaled for movement along all three axes.

Abstract: A dual-acting relief valve is shown which senses fluid pressure above a desired amount in either of two control conduits and operates to interconnect the conduits, thus permitting a higher pressure to be vented to the lower pressure. The two conduits are interconnected by means of an intersecting chamber containing a ported sleeve and either a poppet valve on a stem or a slide valve in association with an isolation piston axially movable in the sleeve for interrupting communication between the conduits. One end of the isolation piston is connected to sense the pressure in one of the conduits, which pressure is opposed by a spring located in a chamber connected to return fluid pressure and thus isolated from control pressure. A bore internal of the valve stem connects the other control conduit with a chamber between the isolation piston and the valve stem.