Abstract: A method and apparatus for converting the intensity of an unknown optical signal (B) into an electrical signal in digital form utilizes two elongated optical attenuators (11, 13), one for the unknown optical signal from a source (10) and one for a known optical signal (A) from a variable source (12), a plurality of photodetectors (e.g., 17, 18) along each attenuator for detecting the intensity of the optical signals, and a plurality of comparators (e.g., 21) connected to the photodetectors in pairs to determine at what points being compared the attenuated known signal equals the attenuated unknown signal. The intensity of the unknown relative to the known is thus determined by the output of a particular comparator. That output is automatically encoded to a relative intensity value in digital form through a balancing feedback control (24) and encoder (23).

Abstract: A single leg mooring terminal is described, of the type which includes a riser extending up from the sea floor to moor a vessel, and a separate fluid conduit extending up from the sea floor to carry oil to or from the vessel, and wherein the riser and hose structure must both rotate without limit about the same vertical axis to follow drifting of the vessel. A turntable near the sea floor, rotatably supports the riser about a vertical axis, and has a hole along its vertical axis through which a portion of the fluid conduit extends. A fluid swivel of the fluid conduit, lies under the turntable and is accessible through a hole in the turntable.

Abstract: A velocity sensing method and apparatus to be used in conjunction with a linear motor having a moveable voice coil. More particularly, an apparatus is disclosed whereby a velocity sensing loop is positioned on a surface defined by wire windings of a linear motor voice coil. The velocity sensing loop is configured so that an end portion is perpendicular to the longitudinal axis of the voice coil and two side portions are parallel to the longitudinal axis of the voice coil. As the end portion of the velocity sensing loop traverses a magnetic field with which the voice coil reacts for positioning thereof, a voltage is induced within the velocity sensing loop which is proportional to the velocity of the loop as it passes through the magnetic field.

Abstract: An improved boat thruster system including a pump for drawing water through an inlet in the boat hull and for discharging water through outlets on both sides of the hull. The improved system includes a plurality of substantially planar vanes mounted in the water flow path proximate to said outlets. The vanes function to reduce swirl angle components in the water flow and thus increase thrust efficiency and to prevent the ingestion of water borne debris into the outlets.

Abstract: A mooring system is provided, of the type that includes several chains extending in loose curves from a mooring buoy at the sea surface to spaced anchor locations at the seabed, which enables the buoy to deflect sidewardly by a further distance and to absorb more energy during such deflection than heretofor, particularly in shallow water mooring. The system includes an anchoring device which holds the lower end of a chain at a level raised high above the sea floor when the chain is pulled taut, while allowing the lower end portion of the chain to lie at a lower level such as at the sea floor when the chain is loose. One system includes an arm having an inner end pivotally mounted near the sea floor and an outer end connected to the lower end of the chain, so that tension in the chain pivots up the outer end of the arm to thereby raise the lower end of the chain.

Abstract: A machine gun pistol is described, which can be reliably switched between semi and full automatic modes by an operator holding the gun in a natural two-hand grip. The gun includes a bolt (20, FIG. 1) and a firing pin device (22) that each slide longitudinally, a trigger assembly with a primary sear (28) that is depressed by the trigger for semiautomatic operation, and an auto control member (34) that can be depressed to switch to full automatic operation. When the control member is depressed, it connects a secondary sear (36) with the primary sear. The bolt carries a cam (40) that depresses the secondary sear (36) every time the bolt moves forward, to thereby repeatedly depress the primary sear (28) when the two sears are connected during automatic operation. The control member (34) is operated by depressing it into the frame, to avoid errors in the heat of battle. The depressable control member (34, FIG.

Abstract: A sandal useful especially in wet areas and also where there is soft ground such as at the beach. The sandal has opposite side edges that slope in a downward-outward direction, to provide a wider foot print that minimizes sideward twisting on soft ground, to avoid splashing of water onto the wearer, and to avoid disintegration of the side portions of soft rubber sandal material. The bottom surface of the sandal slopes upward at the rear and front to further avoid splashing of water onto the wearer. The lower surface of the sandal has a herringbone pattern, with each ridge interrupted by narrow cross projections that help avoid splipping due to hydroplaning.

Abstract: A hybrid ring useful in the microwave and millimeter wave regions as a mixer for producing an IF output signal in response to applied LO and RF input signals. The ring is designed to exhibit a narrow bandwidth at the LO signal port and a moderately broad bandwidth at the RF signal port.

Abstract: In a positive feed power drill having a spindle drive gear train and a spindle feed gear train, and having hydraulic (air) means for actuating a piston to disengage the feed gear train for automatic retraction of the spindle, provision is made for field alteration of a valve in the hydraulic system, and associated actuating mechanism, to automatically reverse the positive feed when the spindle has been driven either (1) a predetermined extent set by a nut on the spindle which engages an arm over a valve stem and pushes the valve stem to a reversing position or (2) to a predetermined stop when countersinking, at which time the spindle stops advancing, thereby causing the spindle feed gear to have a tendency to move upwardly in the spindle actuator housing.

Abstract: A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

Abstract: High frequency medical breathing apparatus is provided, which delivers efficiently controlled high frequency air pulses to a catheter, and which is of relatively low cost and is energized by pressured air that is commonly available in a hospital environment. The apparatus includes a large flexible bag with entrance and exit openings, walls forming a sealed chamber around the bag, and a source that applies pressure pulses to the chamber to partially compress the bag at each pulse so as to deliver air through the exit end of the bag and a check valve, and into a catheter that leads to a patient's lungs.

Abstract: An arrangement for attaching a fan-fixture unit substantially flush with a ceiling includes first and second bowl shaped circular members with cylindrical rims. One of the members is fixedly attached to the ceiling electrical outlet box and the other to the top of the fan-fixture unit. One of the members includes a plurality of uniquely shaped slots and the other member a plurality of support rods, each accommodatable in a slot. To attach the unit, it is raisable by a single operator until the support rods are in the slots. Thereafter, the unit is rotatable and released, resulting in the rods being locked securely within particularly shaped portions of the slots.

Abstract: A stacked-disc structure is comprised of a stack of annular discs (13) scalloped along the outer edge to provide lobes (13a) and etched on one side to provide lands (13a). A web (13d) is retained in the lobes to strengthen the discs so that they will not collapse due to high fluid pressure. The stack of discs is retained by a housing (10) having a fluted interior wall to retain the ends of the lobes. End plates (11 and 12) secure the stack of discs with a spacer (14) at one end having lands (14a) on lobes which match the lobes of the stacked discs to allow fluid to flow into, or out of, the spaces between the lobes of the stacked discs. The spaces between the lands on the etched discs provide passages for fluid flow into or out of the hollow core of the stack. The height of the lands (i.e., depth of the etch) determines the size of the smallest particle that will be permitted to flow through.

Abstract: A chest X-ray unit is provided which is of compact design and which can be easily utilized. The apparatus includes an exposure station at the front where a film sheet can be tightly held between a pair of intensifier screens, a supply station behind the exposure station for receiving a film cassette and feeding one sheet at a time into the exposure station, and a receiving cassette at the back of the apparatus for receiving one exposed sheet at a time for later developing. A film sheet is moved in a loop from the supply cassette to the exposure station by a pair of input rollers that move the sheet upwardly into a curved guide that extends in a half circle, and by a pair of output rollers at the end of the loop for feeding the sheet downwardly. The output rollers move slightly faster than the input rollers to prevent the middle of the film sheet from scraping against the guide.

Abstract: A lowpass filter circuit having an electronically controllable cutoff frequency and utilizing a feedback current mirror circuit as a variable impedance element. The filter circuit employs low noise, low distortion output circuitry and includes means for electronically controlling resonance.

Abstract: A printer/plotter system for producing a multiple color hard copy output in response to digital input data. The system includes one or more impact hammers, each capable of printing a single dot with the hammers being arranged to selectively print dots along a defined print line. The system further includes an ink ribbon having multiple zones of different colors carrying encoded identifying indicia. In response to input data defining a dot pattern and the color in which it is to be printed, the ribbon is searched to position the first identified ribbon color zone in front of the impact hammers. After the pattern for that color is printed, the ribbon is again searched and the next identified color zone is moved into print station, i.e. in front of the impact hammers, and the pattern associated therewith is printed. A paper control system is provided to move the paper to be printed upon in a forward direction as information is printed in each color.

Abstract: By moving a wedge (18) within the radiographic field during exposure of an area of interest, steps of the wedge are presented one by one at the same film location over sequential exposures. Wedge steps are thus superimposed over an identical position within the radiographic field, and a correlation may then be made between wedge step thickness and film optical density over successive exposures for calibrating the radiographs. A preferred form of the stepped wedge is circular (FIG. 2). An alternate form is a circular ramp (FIG. 3).

Abstract: A system is described for coating a cylindrical surface of a long thin workpiece by a process which includes flame spray coating that heats the workpiece to a large portion of its melting temperature and which is followed by grinding of the coated cylindrical surface, which produces a final coated surface of more uniform coating thickness than heretofore. The workpiece is rotated about a vertical axis, to avoid slight bending deformation of it, the upper end of the workpiece is allowed to move slightly towards and away from its opposite end, and an upward bias is applied to the chuck device that engages the upper end of the rotating workpiece to avoid column-like buckling of it.