Abstract: Reinforced composite tubes having integral tapered ends are formed on mandrels which are tapered at each end. Reinforcement fabric is first conformed to the mandrel with at least one end of the fabric structure retaining an opening therein. The mandrel is disassembled and removed through the opening, and a matrix cured within the fabric to produce the desired composite. Usually, the fabric structure will be cured in an external mold with an inflatable mandrel inserted through the opening applying internal pressure.

Abstract: A connector system for joining a male tube to a female tube comprises an axially-split nut which extends across the region being joined. The female tube is externally threaded and mates with internal threads on one end of the axially-split nut. A shoulder formed in the other end of the axially-split nut engages a retaining ring formed on the male tube. A compressible seal ring is disposed between the end of the female tube and a second shoulder of the retaining ring. An external nut is placed over the axially-split nut to hold the entire assembly together and provide a radially compressive force on the seal ring. An axially compressive force can be provided by turning the female tube to draw the female and male tubes closer together.

Abstract: A seal and seat for ball valves is a circular, elastomeric open torus which is fitted between the ball element and the housing. The open torus has within it, a substantially "v" shaped spring that is fitted within the "u" shaped opening of the torus. In normal operation, the spring member is slightly compressed between the ball and the housing and the ball can "float" between a pair of substantially similar seals on the input and output sides of the ball valve, respectively.

Abstract: A detection system for determining the level of a liquid in a containment tank includes a containment tank and a reference standard of known weight mounted to the vehicle and movable along the yaw axis of the vehicle. Load cells are placed intermediate the tank and reference standard to provide analog voltage outputs in proportion to the load on each cell. The load cell outputs, when amplified, summed and then divided by the output of the reference weight load cell, provide an electronic signal that is proportional to the gross weight of the tank. A pre-set signal, representative of the empty weight of the tank, is subtracted from the gross weight signal, resulting in a signal which is proportional to the net weight, or the contents of the tank.

Abstract: Aluminum oxide ceramic composite articles having high flexural and tensile strength are produced by introducing a liquid aluminum oxide precursor material into a ceramic reinforcement fabric, curing the precursor material at an elevated temperature, and converting the cured precursor material to an aluminum oxide ceramic by pyrolysis at temperatures which do not result in the degradation of the reinforcement material. Such ceramic composite articles are particularly useful for applications requiring a low dielectric constant and a high mechanical strength.

Abstract: An apparatus and method for providing optical switching or color selection capability uses cholesteric liquid crystals which reflect and transmit circularly polarized light and a variable wave retarder element together with phase reversing mirrors which recapture and recombine the reflected circularly polarized light. With the retarder element in a first state, first orientation circularly polarized light is completely transmitted and second orientation circularly polarized light is redirected. Alternatively, a color selection assembly is provided through the use of a combination of cholesteric light crystals in which light of a first color is given a first polarization orientation and light of a second color is given a second polarization orientation. Depending upon the state of the retarder either the first or second color is transmitted to a desired target.

Abstract: A helmet system includes a helmet shell and an energy-absorbing helmet liner that is constructed from an open-cell urethane foam impregnated with a room-temperature curable thermoset epoxy. The impregnated foam liner is inserted in the helmet shell, heated until the liner becomes deformably plastic, and placed on the head of a user, permitting custom-fitting of the helmet system that conforms to the contours of the user's head. When cured by cooling, the liner assumes a rigid construction that, by custom-fitting, repeatably aligns the helmet shell to the head of the user, and is crushable to absorb energy.

Abstract: An access port cover is fitted with a sealing plug that is adapted to fit inside a conduit to provide an occluding seal. The conduit is also fitted with an inner flap that is automatically closed and latched when the cover is closed and latched. In a preferred embodiment, a ridge in the inner wall of the conduit cooperates with a support plate to compress the plug between the cover and the plate, extruding the plug radially into sealing engagement with the inner wall of the conduit.

Abstract: A coupling device includes male and female telescoping members that are inserted into a fluid carrying hose or conduit. The coupling device includes an O-ring for providing fluid tight seal and a frangible locking ring that will separate when oppositely directed forces exceed a predetermined threshold. The locking ring includes a split so that it can be compressed to a smaller diameter for installation and, in the preferred embodiment, a plurality of frangible radial tabs. In an alternative embodiment, the ring may have a radially extending flange with a parting groove at the juncture of the ring and flange. One of the coupling device members includes a groove that holds the ring and the other member includes a groove that receives the radial tabs or flange.

Abstract: An air cushioned safety and/or display helmet. A thin cushion of air between the wearer's head and the inside of the helmet supports the helmet and distributes the helmet's weight evenly thus preventing development of pressure points and corresponding wearer fatigue. When used in a high performance environment which exposes the user to g forces, such as fighter aircraft, an air regulator controls the air pressure of the air cushion in response to these forces to maintain helmet position and comfort. Air contained in the air cushion can also be used to demist the helmet visor and display optics, can be directed past the head to provide heating or cooling of the head, or can do both at one time.

Abstract: An improved optical display system, such as a head-up display system. A highly transmissive light-weight and shatterproof optical combiner is provided. The combiner includes at least one cholesteric liquid crystal element for transmitting a first image in a line of sight and for reflecting a second image into the line of sight. Multiple cholesteric elements are used in a multicolor shutter, a multicolor combiner, and a multicolor collimator to display a multicolor image.

Abstract: Pairs of level sensing devices are used in a method that aligns plane surfaces to one another. One of the pairs of level sensing devices is located on each of the plane surfaces. The level sensing devices of each pair are aligned and positioned parallel to two orthogonal axes of the plane. The output signals from corresponding ones of the pairs are differentially compared, and one of the platforms adjusted in pitch and roll to minimize the values produced by the differential comparison. The platforms are then tilted equal amounts and adjusted in azimuth.

Abstract: A high precision optical filter includes a wideband filter element and a cholesteric liquid crystal notch filter element. In one embodiment, a wideband infrared filter blocks infrared wavelengths beginning at a nearly visible corner wavelength and a cholesteric liquid crystal filter blocks transmission of infrared wavelengths in a precise narrow band that includes the corner wavelength and that extends down to visible wavelengths. The liquid crystal filter may include a polymer for maintaining maximum reflectivity of the filter near the corner wavelength over an anticipated operating temperature range. The combined optical filter may be fabricated by depositing a matched pair of liquid crystal cholesteric films on a glass infrared filter element. In another embodiment, an optical filter according to the invention forms an eyepiece in a night vision goggles assembly for blocking visible light.

Abstract: A field sequential color shutter display system including a light source emitting light rays having substantially first and second different primary colors. First and second light polarizing filters are included. The filters are aligned in optical communication with the source. Each filter includes a color selective polarizing filter having substantially orthogonally oriented absorption axes. The first absorption axis of each light polarizing filter passes linearly polarized light of the first color and a uniform first polarization. The second absorption axis of each light polarizing filter passes linearly polarized light of both the first and second colors and a uniform second polarization. Variable optical retarding filters are disposed between the first and second light polarizing filters.

Abstract: A head-up display (HUD)/head-down display (HDD) system capable of projecting multi-color images employs cholesteric liquid crystal elements, two-state liquid crystal devices, an image source, a beam splitter, and a combiner to, in sequence, generate HUD and HDD images. An LCD and cholesteric liquid crystal element operate together to selectively transmit or block portions of an image incident thereon. The switching frequency of the LCD-cholesteric liquid crystal element is above the flicker-fusion frequency, such that both the HUD and HDD displays appear to the observer to be simultaneously and continuously operating.

Abstract: A non recirculating, low volume toilet system for aircraft includes a interim storage tank connected to the toilet bowl. A waste drain leads to a gate valve which opens to a vacuum assisted luid gas separator. The separator is connected to the main waste tank. In a first embodiment, the main waste tank is a non pressurizable vessel and is maintained within a pressurized portion of the aircraft. The separator is alternatively connected to the exterior environment and the pressurized interior. When the toilet is utilized, the flushing operation uses a very small amount of flushing fluid to clean the bowl and transfer the contents to the interim tank. Opening the gate valve subjects the bowl and the interim tank to a pressure differential which transfers the flushing liquid and waste matter to the separator. The gate valve is closed and the separator is permitted to reach pressure equilibrium with the main waste tank at which time the contents of the separator are transferred to the main waste tank.

Abstract: A waste tank cleaning system in a preferred embodiment includes a flowmeter interposed in the line carrying cleaning fluid to the tank. A pair of solenoid valves are controlled by an electronic counter coupled to the flowmeter. In response to predetermined volumetric flows of fluid, the solenoid valves alternatively deliver fluid to a hydraulically operated drain valve and to a spray/rinse outlet in the waste tank. In one alternative embodiment, a flowmeter is mechanically coupled to a valve structure which alternatively applies fluid to the drain valve and to a spray/rinse outlet in the tank, directly. In other embodiments, the volume of flow can be determined by liquid level sensors in the tank and a predetermined cleaning sequence can be carried out based on the signals sent by the sensors. Power can be furnished by a rechargeable power supply.

Abstract: The valve includes an electromagnet having a pole face inclined at an angle to a disk-shaped poppet or valve plate to define a wedge-shaped air gap therebetween. A peripheral housing surrounds the plate and extends between the pole face and a planar floor below the plate to define a chamber within which the plate is loosely captivated for pivotal movement about an edge of the plate disposed at the thin end of the gap. The floor contains a valve seat disposed toward the thick end of the gap so that the plate experiences its maximum stroke in the vicinity of the seat, thus resulting in a faster-acting valve for a given effective stroke length.

Abstract: A multiple image, single display system (2) includes a monochromatic display source (4) which provides first and second rapidly alternating visual images (8, 10) which pass through an active polarizer assembly (14). The polarizer assembly includes an image polarizer (20), which polarizes all the light to a left hand circular polarization, and a polarization changer (22) coupled to the display source by a synchronizer 28). The polarization changer switches the polarization of the first image but not the second image. A first user (34) sees the first image, but not the second image, through a right hand circular user polarizer (16) while a second user (36) sees the second image, but not the first image, through a left hand circular user polarizer (18). The user polarizers are wave-length sensitive so they block light only if the light has the same polarization and if the light is the wavelength of the light produced by the display source; the user polarizers are otherwise transparent to visible light.

Abstract: A stereoscopic display capable of displaying monochromatic or colored views of moving, three dimensional scenes comprises means for sequentially projecting alternate ones of successive pairs of substantially monochromatic images corresponding to right-eye and left-eye perspectives of the scene at a display rate sufficient to avoid a perception of flicker in the images. A variable polarizer is used to circularly polarize alternate ones of the images in respectively opposite senses synchronously at their projection rate. The images are analyzed by highly-transmissive eyewear comprising at least one pair of oppositely-sensed cholesteric liquid crystal circular polarizers tuned to the particular color wavelength of the images and disposed, one over each eye, to transmit appropriately-polarized images to corresponding eyes and to reflect inappropriately-polarized images away therefrom.