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: 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: 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: 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: 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.

Abstract: An improved solenoid poppet valve includes an endless magnetic gap loop which overlies the valve chamber. The axis of the poppet valve intersects the magnetic gap and can be self centered by the energizing of the solenoid. The valve chamber can be sealed from the solenoid coil and magnetic poles using a relatively thin isolating material which can be fully supported by the magnetic pole structure. A novel dual rate spring combination supports and centers the poppets in the valve chamber. The spring provides one force to maintained the valve in the closed position and a second, greater force to "kick" the poppet away from the magnetic poles when the solenoid is deenergized. In alternative embodiments, the valve of the present invention can control the flow of one or several fluids. Yet other embodiments can provide several valves to control the flow of a single fluid.

Abstract: An apparatus and method for producing a color display from a substantially monochromatic source utilizes a liquid crystal cell combination together with a plechroic filter to differentially polarize the light components comprising the light emitted from the source. The liquid crystal cells are connected in push-pull fashion to individually retard light by one fourth of a wave as a function of the control signal applied to them. A fourth wave plate followed by a linear polarizer completes the optical combination. A signal at a first level applied to the cells causes transmission of one component color and blocks the other. A signal at a second level blocks the one component color and transmits the other. An intermediate level signal transmits both colors, resulting in a third, combination color.

Abstract: A display apparatus for use with headgear, includes in combination visor means adapted to attach to the headgear and having a visor viewing area segment positioned in the line-of-sight of a wearer of the headgear. Optical display generating means are adapted to be attached to the headgear. Parabolic mirror means are interposed in the optical path from the optical display generating means to the visor viewing area segment. Fold mirror means, including at least one fold mirror positioned to receive the image from the parabolic mirror means for directing the image to the visor viewing area segment, is provided, whereby the size and curvature of the visor can be minimized without affecting transmission of the image.

Abstract: A visor for mounting on a helmet adapted to be worn by an individual, includes a substantially transparent visor having an inner concave surface, and, with reference to an orthogonal, right-handed xyz Cartesian coordinate system of spatial reference having its origin located on the inner concave surface and its z-axis parallel to the line of sight of the individual wearing the helmet, the inner concave surface being defined by a cross-section of the visor in the x-axis of reference, which is symmetrical about both the origin and the y-z plane of reference, having one-half of the cross-section of the visor in the x-axis of reference being a first circular segment containing the origin at one end and connected to its opposite end to one end of a first paraboloid segment which is connected at its opposite end to one end of an elliptic segment whose opposite end forms a side boundary of the visor, and by a cross-section of the visor in the y-axis of reference having a second circular segment, one end of which for

Abstract: Gate valve means connected in a waste pipe system have a hollow housing with an inlet and an outlet connected to the waste pipe system. A blade is disposed in the housing at a substantially right angle to the waste pipe system and is selectively movable between a closed position blocking the inlet from the outlet, and an open position allowing waste flow between the inlet and outlet. The blade moves between the open and closed positions and a pair of seals are disposed in the housing in an abutting relationship aligned to receive the blade therebetween when in the closed position and to seal waste flow between the inlet and outlet from the interior of the housing when the blade is in the open position. Each of the pair of seals has a unique design enabling it to mechanically rotate with the blade, thereby limiting wearing forces thereon.

Abstract: A non obstructing, flap type valve for a circular conduit is defined as a right angle section from a cylinder wall of the same diameter. A mating, right angle section taken from the end of the circular conduit defines the valve seat. The valve is end mounted and pivots from a closed sealing configuration to an open, free flow position. A flattened rod cooperates with a cam surface to lock the valve in the closed position, or a bias spring may maintain the valve closed.

Abstract: A flexible stick tank gauge is made of a thin metal or plastic tape. The tape is sufficiently thick to be self-supporting when held vertically from the lower end. Alternatively, the tape is curved to be a narrow sector of a cylinder. Measuring indicia are applied to at least one surface of the tape. The tape remains flexible at extreme environments of temperatures and will not break in normal use such as airline fuel measuring operations.

Abstract: A direct reading tank gauge is made of plastic tape or thin metal in an endless loop. Measuring indicia are applied to one surface of the tape in a display tape assembly. An armature is fixedly mounted to the tape. A tank float is magnetically coupled to the armature, which follows the float and fluid level. A hinged window enables visual observation of tape indicia representing the position of the float, armature and liquid level and removal of the entire display tape assembly for service or repair.

Abstract: A hydraulically operated drain valve is interposed in the cleaning fluid path before the spray/rinse outlet. The fluid under pressure activates a piston which operates the drain valve. A precharge reservoir is also interposed in the supply line before the spray rinse outlet to store a measured precharge which drains into the tank after the drain valve has closed. A manual override is provided to open the drain valve in the event of a failure of the hydraulic system.