Abstract: A strain sensitive element for use in a system for converting mechanical movement of portions of the element which are movable relative to each other into electrical signals, includes a planar substrate including an N-type silicon material wherein the substrate includes grooves extending into the substrate defining an integral hinge portion between at least two relatively movable parts. At least one strain gage extends across a groove without any separate support so that the strain gage and the hinge portion are spaced apart. The strain gage is joined to two of the relatively movable parts of the substrate. At least one elongate frangible link extends across a concave pit in the substrate. The frangible link is derived from the same silicon material as the substrate. The midportion of the frangible link is spaced from the lower surface of the pit and the end portions of the frangible link are joined to the substrate. At least one resistor is provided.

Abstract: A high pressure pilot operated valve includes a housing with inlet and outlet passages, an internal bore communicating the passages and slide valve member movable between a first position blocking fluid flow and a second position permitting fluid flow. A spring in a low pressure chamber urges the slide valve member in the closing direction. A stem on the opposite end of the slide valve member is selectively exposed to a control pressure by means of a pilot valve connected to high pressure fluid to cause the slide valve member to move to the second position. The inlet passage communicates with the hollow interior of the slide valve member and with metering orifices in its sidewalls. A passage in the slide valve member having a radial conduit opening against the bore near its stem end connects the outlet passage with a low pressure chamber when the slide valve member is in the first position and is blocked when in the second position.

Abstract: A vibration isolation module (30) includes termination members (34, 36) at each end to which are connected electrical wires or cable (39), and a braided rope of aramid fiber (32). A plurality of compliant members (40) of polyurethane hose having tapered ends are inserted at intervals within the braided strands of the rope (32). Some of the compliant members (40) may be filled solid with polyurethane. Variable lengths of hose or variable diameters and wall thicknesses may be used to vary the compliance of the compliant members (40). Between the compliant members (40) are positioned a number of spacer members (38) which provide support for the hose (37) and electrical wires (39). This structure is carried within an oil filled stretchable hose (37) fastened to the termination members. When the module (30) is subjected to forces in tension, the load is carried by the aramid fiber rope (32) which, as the load is increased, tends to squeeze down and compress the compliant members (40).

Abstract: An electrical tilt switch includes a generally cylindrical cap member having a hollow interior with an internal inwardly extending ridge positioned a significant distance above its lower edge, a flat, generally cylindrical base member having a concave dished upper face, an annular insulating member interposed between the base and cap and fastened to each, electrical leads attached to the base and cap members, and a spherical contact member carried on the dished surface and movable against the ridge when the switch is tilted to a specified angle. For severe environmental conditions the preferred material for the cap, base and spherical contact member is a K Monel alloy.

Abstract: A digital drive system for a pulse width modulated power control utilizes an output transformer driving a load device with the transformer primary winding being connected to a pair of power output devices such as field effect transistors. Each of the output devices is switched on and off from a flip-flop whose "on" and "off" time is controlled by means of digital counters and gate devices, the times of "off" and "on" cycles being controlled by a digital counter connected to a clock and receiving amplitude information from a digital register which is programmable to vary the count of the amplitude counter with a desired variation in amplitude. By programming the gate devices to switch from one flip-flop to the other with an identical clock count, the two half cycles of the output signal supplied to the transformer are maintained identical and ensure that the transformer core is not saturated.

Abstract: A ballistic tolerant linear actuator incorporates a piston (16, 46, 76) and piston rod (38, 42 or 48, 50 or 90, 92) within a cylindrical housing (58, 60 or 81, 88) connected at each end (14, 22 or 42, 54 or 74, 82) to a source of fluid. A sleeve (18, 62 or 88) of a metal matrix or composite material which will break or puncture but which will not bend or petal on impact is incorporated as part of the barrel within which the piston is translated. The piston rod which extends through at least one end of the cylindrical housing is formed with an external sleeve of the metal matrix or composite material (38, 50 or 92) spaced from an internal load carrying metal rod (42, 48 or 96).

Abstract: A self-propelled spherical vehicle (10) for operation in a fluid medium utilizes an impeller (12) of approximately half the diameter of the sphere for propulsion. In addition to driving the vehicle, the impeller acts to draw the flow of fluid smoothly over the after part of the sphere, thus avoiding or minimizing the tendency of the fluid flow to separate from the surface and create turbulence. Compensation for impeller torque is effected in one embodiment by a series of non-rotating stator blades (14) carried coaxially of and immediately aft of the impeller and which are curved to counter the torque of the impeller on the vehicle. The stator structure is supported at the rear of the housing by brackets (18) including pivotal supports providing support in the vertical plane.

Abstract: A construction and method of producing an elongated underwater acoustic array includes a plurality of interconnected hydrophones and circuit modules protected by a plastic foam cushioning sheath, covered with a tough, essentially acoustically transparent hose-like jacket and containing a plurality of aramid fiber ropes as strength members to carry the tensile loads on the array. An elongated tube-like fabric retaining member is interposed between the sheath and the exterior hose jacket which is longitudinally stitched to provide a plurality of spaced parallel tubes, each of which is of just sufficient diameter to contain one of said strength members. The strength members are terminated at a connector at each end of the array, and a spacer member is placed near each connector to spread the strength member ropes to the desired diameter. The spacer members and the adjacent ends of the retaining members are each cemented to the strength member ropes.

Abstract: A method of bonding a metal termination member including an electrical connector to an electrical cable designed for underwater operation having a plurality of insulated electrical wires, an internal armor layer of spirally wound wires, and a tough polyurethane protective jacket including the steps of splitting the external jacket longitudinally and peeling it away from the remainder of the cable, connecting the electrical wires to the connector member, attaching the wires of the armor layer to the termination member, cleaning and priming the metal surfaces of the termination member and the armor wires with a suitable thermoplastic adhesive which will adhere to metal and to polyurethane, repositioning the split halves of the polyurethane jacket around the end of the cable and the termination member, placing the termination assembly in a mold and subjecting it to heat and pressure sufficient to cause the polyurethane jacket material to flow sufficiently to bond the split halves of the jacket together and to th

Abstract: A spool valve and seal having zero leakage includes a spool valve member having a hollow interior translatable within a bore in a valve body with inlet pressure connected through ports to the hollow interior of the spool valve member. A series of radial orifices axially displaced from the inlet ports communicate the interior with the exterior surface of said spool valve member, the outlets of said orifices terminating in chamfered edges. A seal is positioned adjacent the spool valve member in an annular groove formed in the surface of the bore within which the spool member is translated, the seal being positioned to prevent leakage between the inlet pressure passages and an outlet chamber in said valve body.

Abstract: A spherical vehicle for operation in a fluid medium utilizes an actuator disk or propeller of approximately half the diameter of the sphere for propulsion. In addition to providing the energy for driving the sphere, the actuator disk acts to draw the flow of fluid smoothly over the after part of the sphere, thus avoiding or minimizing the tendency of the flow to separate from the surface of the sphere and create turbulence. For aircraft launch, a heavy shroud protects the actuator disk propeller and assures that the vehicle will sink rapidly after impact. The shroud is jettisoned at a desired depth. Steering in pitch and yaw planes is effected through the use of a plurality of powered thrusters located at or just behind the circle of maximum diameter (with respect to the direction of motion) and selectively actuated by a guidance or control system. Alternatively a single reversible thruster may be used for steering in yaw combined with a movable internal weight for pitch control.

Abstract: A liquid spring accumulator includes a housing having inlet and outlet ports connected to a source of liquid under pressure. The housing contains a high pressure chamber and a cylindrical chamber containing a spring-loaded piston. A rod attached to the piston is movable therewith into the high pressure chamber. A passageway through the axis of the piston and rod provides communication between the inlet port and the high pressure chamber and includes a valve seat. A check valve member in the passageway includes a shaft holding the movable member off its seat during initial flow of hydraulic liquid into cylinder, permitting flow to fill the high pressure chamber. As the liquid pressure increases, the initial movement of the piston permits the check valve to close, and still further increases in pressure cause the piston to force the rod into the high pressure chamber, substantially increasing its hydraulic pressure.

Abstract: A sonar transceiver system and method includes an oscillator and programmable divider which are arranged to cause a transmitting transducer to transmit a plurality of four consecutive closely spaced tones in the manner of a pseudo-chirp. The receiver includes hard limiting means for converting received echo signals to binary signals and tone correlation and detection means including a shift register which compares samples of the binary received signal with a sample of a sine wave as hard limited which is carried on a storage register. A series of exclusive-OR comparator circuits effect the comparison and produce output signals of a desired magnitude when correlations are found. Switching means responsive to detection of the first of the transmitted tones causes the programming means to vary the divisors of the programmable divider to produce clock pulses of varying frequency to the shift register for the time and in the order of the transmitted tones.

Abstract: A sonar fish counter, primarily for counting salmon migrating in streams and for providing a separate count of king salmon, includes a narrow beamwidth side-scanning sonar transducer directed to insonify a volume of water in the stream directly above a mechanical beam which serves as an artificial bottom. The transducer transmits pulses of short duration such as 100 microseconds at regular intervals. After a delay following a transmitted pulse, a receiver is enabled to receive echo signals from any fish crossing the artificial bottom. During the period the receiver is enabled, a ring counter separates the return echoes on the basis of the return time from respective sectors of the bottom structure, and these returns are separately counted for each sector so that the counts may be displayed or printed separately.

Abstract: A combination hydraulic lock and pressure relief valve for use in an actuator system for operating a spoiler control surface is interposed between the retract side of the actuating piston and the servo valve controlling the piston. In this valve a poppet urged closed against a seat member by means of a light spring aided by the fluid pressure in the retract chamber of the piston holds the poppet closed whenever the system is shut down. A piston exposed to supply pressure carries a spring retainer which includes an elongated rod movable to dislodge the poppet from its seat to permit fluid to move toward and from the retract side of the piston during normal operation of the spoiler. A second retainer abuts against the seat and a heavy spring is interposed between the spring retainers. The seat member is loaded by the heavy spring to a predetermined level above normal system pressure.

Abstract: A drive mechanism for a drill provides both rotational drive and axial feed for a drill of substantial diameter such as those used to drill holes for roof bolts in mine shafts. A plurality of sprockets carry two chains of drive links which interlock around the drill shaft with each drive link having depressions which mate with scroll-like projections on the drill shaft. For axial feed, the sprockets are driven from worm drives in separate housings on each side of the chains, the worm drives being driven from gears in a gearbox which are connected through a differential gearset to a hydraulic motor. A second hydraulic motor also drives through the differential gearset to rotate the drill shaft and the entire drive chain assembly. A large diameter face seal serves as the partition between the chain drive assembly and the gearbox.

Abstract: A propulsion system for an underwater vehicle includes a solid propellant gas generator producing gas which drives a gas turbine. The turbine drives one, or alternately two, centrifugal pumps which induct sea water from intake ports and supply it under pressure through a passage to passages leading to tip nozzles in the blades of a propeller which drives the vehicle, thereby using the reaction force from the tip nozzles to drive the propeller. Exhaust gas, after driving the turbine, is conducted through a conduit and to an annular chamber where it is cooled by means of a spray of sea water, thus condensing the steam present and reducing the volume of exhaust gas.

Abstract: A wind turbine blade of large size for a wind turbine (14) having three blades (16) and used to generate electrical power is contoured to minimize stalling and to provide unusually good efficiency. The cross section of the blade tapers from a configuration at the hub or inboard end with substantial leading and trailing edge deflection toward the wind providing high lift at low speed, to the outboard one-fourth to one-fifth which is configured as a conventional low lift airfoil since it moves through the air at comparatively high speed. The chord length of approximately the inboard one-third of the blade is chosen such that, in combination with the deflection, very little air is permitted to cross this inboard part of the blade but is forced to flow radially outwardly such that by reason of an increase in dynamic pressure it augments the flow across the faster moving part of the blade.

Abstract: A funnel construction for a dipping sonar system carried in a helicopter includes the opening to a cylindrical housing of glass epoxy material for storing an underwater transducer which is deployed by suspending it into a body of water at the end of a thin cable. The housing opening includes a flared funnel structure including an entrance aperture member of thin wall aluminum alloy, a backing structure including a frustoconical strut member secured to the bottom of the helicopter and a resilient foam material positioned between and bonded to the entrance aperture member and the strut member which permits the entrance aperture member to move somewhat when impacted by the transducer. The aluminum alloy material in the entrance aperture is very light and yet transfers the heat of friction from rubbing of the small diameter cable against itself sufficiently rapidly that very little wear or damage is caused to either the cable or the funnel structure from repeated high speed reeling cycles.

Abstract: A spherical vehicle for operation in a fluid medium utilizes an impeller of approximately half the diameter of the sphere for propulsion. In addition to providing the energy for driving the sphere, the propeller acts to draw the flow of fluid smoothly over the after part of the sphere, thus avoiding or minimizing the tendency of the flow to separate from the surface of the sphere and create turbulence. Steering in pitch and yaw planes is effected through the use of a plurality of drag pins located just behind the circle of maximum diameter (with respect to the direction of motion) and selectively actuated by a guidance or control system. A plurality of stub vortex generators are also located on the after side of the sphere and are angled to oppose the torque created by the propeller. The center of gravity is located substantially below the geometric center of the sphere.