Abstract: A metal detection system for a portable radio is provided. The metal detection system comprises a magnet coupled to a substrate, such as a belt, the magnet generating a magnetic field. The system further comprises a magnetometer coupled to the substrate, the magnetometer measuring changes in the magnet's magnetic field strength indicative of metal accessories being within a predetermined proximity of the magnet. The removal of accessories, such as law enforcement accessories (for example handcuffs) can be detected. The portable radio detects changes to the magnetic field in response to changes in location of the metal accessories. The portable radio can transmit a signal in response to accessories being removed from the substrate.

Abstract: Tank level indicators are known, having a sensor housing in which a resistance card having a resistance strip, and a wiper acting with the resistance path and rotatable about an axis of rotation. The variable rotating resistance is encapsulated relative to the fuel in the sensor housing, so that no fuel can enter the sensor housing. It is disadvantageous that the wiper slides dryly against the resistance path, because this gives rise to increased friction and increased wear on the resistance path. The wear particles collect in the sensor housing, and can negatively influence the contact between the wiper and the resistance path. According to the invention, the protection of the tank level indicator relative to particles or ice crystals is improved. It is also ensured that particles or ice crystals that enter the tank level indicator can flow out of the housing of the tank level indicator.

Abstract: An Improvement to enhance the usability of magnetic compasses by eliminating acceleration and turning errors, especially in aviation applications, without compromising simplicity and reliability. The improvement includes the addition of a weightless mass to the bar magnet of a conventional magnetic compass to counteract undesirable inertial forces on the bar magnet.

Abstract: A method of preventing air bubbles in a compass equipped with fluid expansion capability, wherein a compass unit is assembled with a fluid expansion diaphragm; the compass unit is filled with fluid expanding the diaphragm, and sealed while maintaining the diaphragm in its expanded state for preventing air bubbles in reduced pressure and/or reduced temperature conditions, without significantly changing the basic structure of the compass.

Abstract: A gimballed compass apparatus is disclosed which provides directional and inclinational data. The apparatus comprises a rotatably mounted slotted disk wherein the slot is continuously varying in width around the circumference of the disk. The disk incorporates an elongated magnet which causes it to rotate in relation to an external magnetic field. A first and second aperture are located on the top and bottom elements of the chamber defining a emission passage. The apertures have a rectangular length approximately the maximum width of the slot. The slotted disk is positioned intermediate the apertures. An emission housing is provided below the chamber and includes an emission source and a first source detector. A second source detector is provided above the chamber. The source detectors provide a response to the intensity of emission incident upon them.

Abstract: An attitude sensor comprises a spherical ball suspended in a fluid contained in a housing. The ball is maintained neutrally buoyant with respect to the fluid and out of direct contact with the housing. A means is provided for detecting the orientation of the ball. The sensor is particularly useful as a compass, in which case one or more magnets may be provided within the ball or a passive magnetic element is provided which is influenced by the earth's magnetic field.

Abstract: A position sensor has a ring of a material of high permeability that is floated on a liquid within a hermetically sealed toroid, so as to hold the ring in a horizontal position. Exciting coils are distributed uniformly about the ring to enclose the cross section thereof, and receiving coils are distributed uniformly about the circumference of the ring.

Abstract: A tilt-compensating magnetic compass formed by a capsule enclosing a rotatable pointer to indicate direction and a rotatable magnetic-field detector provided with a permanent magnet. The detector, which is rotatable about an axis colinear with the axis about which the pointer rotates, orients itself with respect to the earth's magnetic field, the detector being tiltable to a degree depending on the inclination of the magnetic field and on the attitude of the compass with respect to the horizontal plane. The detector is mechanically linked to the pointer so that rotation of the detector results in a corresponding rotation of the pointer regardless of the degree of tilt, whereby the pointer accurately indicates direction. The linkage consists of a pin projecting from the detector and passing through a slot in a fork extending from the pointer, whereby when the detector tilts, the pin then shifts within the slot, but remains coupled to the fork to maintain the linkage without imparting movement to the pointer.

Abstract: An inclinometer 20 has a sensing unit 40 for providing a varying capacitance signal depending on the orientation of the inclinometer 20. An oscillator circuit unit 82 includes the sensor unit 40 as a capacitive element for providing a signal having a period and a frequency depending on the capacitance of the sensor unit 40. A unit 92 is provided for determining the period of the signal. A look-up table unit 96 stores a predetermined relationship between the period of the signal and the angle of orientation of the inclinometer 20. A comparison unit 94 then compares the period of the signal to the period stored in the look-up table unit 96 and selects the corresponding angle which is the angle of orientation of the inclinometer 20. The angle is then displayed on the inclinometer display 25.

Abstract: A clinometer includes a cylindrical cavity having a conductive cylindrical wall and a vertical annular wall having a high resistance resistor uniformly distributed thereon. A freely moving, heavy conductive ball, which may be solid or liquid such as mercury, seeks the lowest point in the cavity. The conductive ball contacts both the conductive cylindrical wall at a point along the resistor, thereby defining the resistance between a terminal connected to one end of the resistor and another terminal connected to the conductive cylindrical wall. This resistance is a function of the inclination of the clinometer. A reference voltage is applied to the end terminal of the resistor. The terminal connected to that conductive cylindrical wall may be coupled to a circuit that converts a voltage across the resistance into a digital voltage that represents the inclination of the clinometer.

Abstract: A clinometer includes a cyclindrical cavity having a conductive cylindrical wall and a vertical annular wall having a high resistance resistor uniformly distributed thereon. A freely moving, heavy conductive ball seeks the lowest point in the cavity. The conductive ball contacts both the conductive cylindrical wall and a point along the resistor, thereby defining the resistance between a terminal connected to one end of the resistor and another terminal connected to the conductive cylindrical wall. This resistance is a function of the inclination of the clinometer. A reference voltage is applied to the end terminal of the resistor. The terminal connected to the conductive cylindrical wall is coupled to a circuit that converts a voltage across the resistance into a digital voltage that represents the inclination of the clinometer.

Abstract: A high resolution, digital inclinometer having a full 360.degree. linear range with accuracy which is independent of the angle of inclination. The linearity of the inclinometer is essentially flat throughout its range and greatly exceeds analog equivalents. A mathematical model to predict resolution is presented which allows the designer to design the device to maximize resolution at transverse angles. The device can be used in a celestial navigational instrument by storing celestial navigation tables and providing clock and inclination angle information so that the device can be pointed at particular stars and a latitude and longitude calculated. The inclinometer is capable of minimizing effects of pressure and/or temperature which cause microbubbles to form within the supporting fluid.

Abstract: A magnetic angular position sensor having a ferrofluid filled spherical chamber in a cylindrical housing, within which floats a body comprising a buoyant core carrying a magnet which aligns itself and the body with the earth's magnetic field, and carrying an odd number of small permanent magnets. Hall effect devices are located in recesses in the ends of the housing. The housing also carries a calibration solenoid.

Abstract: An inclinometer for producing high resolution signals of inclination relative to various references and which is capable of displaying inclination angles in various modes. High resolution data signals are produced through the use of a digital encoding wheel which is suspended in equilibrium in a fluid to substantially eliminate frictional forces. A microprocessor, or state logic machine is used to analyze and process the data to provide various displays of inclination including an audible output.

Abstract: The invention relates to a universally movable suspension member for a direction indicating display system, especially for a gyro system (2), in which a bellows unit (1) is provided between a revolving disk (3) and the gyro system (2). The suspension member is designed as a double-bellows unit including two oppositely folded bellows (5, 6) so that, while a reliable and accurate indication is obtained, the volume of construction is decreased and the manufacturing costs are reduced.

Abstract: A viscous dampened sensitive pendulum carries a generally upwardly directed light source for indicating the gravity vertical. The sensitive pendulum is carried for two degrees of pivotal freedom by flexural pivots which are biased for operation at an error free or hysteresis free zero spring rate for small pivotal deflections. A drive pendulum coupled through the flexural pivots to the sensitive pendulum maintains a small pivotal deflection so that error free, zero spring rate, operation is achieved.

Abstract: A cylindrical compass gimballing and data readout system permitting 360.degree. rotation about both yaw and roll axes includes a cylindrical compass housing flooded with semiconductive fluid to permit transmission of a digitally multiplexed signal from a remote reading compass to a processing unit in which the fluid is interposed between spaced-apart plates located along and perpendicular to the roll axis of the compass. This permits electrical connection to and from the compass, and permits not only 360.degree. rotation about the yaw axis for compass heading readout, but also 360.degree. rotation of the compass about the roll axis to permit use in seismic streamers.

Abstract: A magnetic compass including a flexible bowl having a rim with an annular inwardly facing groove. The inwardly facing groove is adapted to engage a flange of a transparent cover in a tight sealing relationship, the combined assembly enclosing a compass rose.

Abstract: A vertical indicating device is comprised of a compound pendulum immersed in a liquid and one or more paddles attached to the pendulum to couple its motion to the liquid. The effective length of the equivalent pendulum is much longer than the physical dimension of the device. The loading on the bearing is minimal, thus, achieving low friction and high accuracy.

Abstract: In this gyro compass the direction-indicating gyro system is suspended pivotably in all directions from a pendulum, which is mounted to rotate about a vertical axis in a frame integral with a ship, and which has on its upper end an element that extends into a tank containing a damping fluid for dampening oscillations of the pendulum.

Abstract: Compass apparatus includes a housing defining a liquid-filled sealed interior space and a compass card member disposed within the liquid-filled space for rotation therein. The housing comprises an upper transparent cover portion having an outwardly directed first flange extending around the perimeter thereof and a lower housing portion, preferably formed of elastic material, having an annular elastic flange extending around the periphery thereof, the upper surface of the latter flange abutting against the lower surface of the first flange in liquid sealing engagement therewith. A connecting ring having a U-shaped cross section maintains the abutting flanges in sealing engagement with each other thereby providing a housing which is simple to close and which may be reopened and reclosed as desired in a manner such that the integrity of the liquid seal is not impaired. A sealing ring member may be provided between the elastic flange of the lower housing portion and the lower flange of the connecting ring.

Abstract: A viscous damping device positioned between a gimbal shaft and a bearing sleeve supporting the gimbal shaft is provided for damping a gyro apparatus in a rotational direction. The viscous damping device comprises first and second rings fixed to an outer periphery of the gimbal shaft. A circular groove provided in the first ring is complementary with a circular protrusion of the second ring, so that damping liquid initially poured into the circular groove is made to fill an air gap between the outer peripheries of the rings and an inner wall of the bearing sleeve by inserting the circular protrusion into the circular groove.

Abstract: A verticality sensor comprises a casing within which is mounted a rotary pick-off device having a body attached to the casing and mounted on a shaft for relative rotational movement with respect thereto, such movement producing an output signal from the pick-off representative of the angular rotation of the casing with respect to the vertical, pendulum means mounted on the pick-off shaft for relative rotational movement with respect thereto, and inertia means fixed to the pick-off shaft and coupled to the pendulum means through a fluid, with which the casing is filled, and through spring means. The arrangement is such that when the pendulum is subjected to lateral accelerations and undergoes rotational movement relative to the pick-off, the spring means is torsioned and thereby attempts to transmit that rotational movement to the inertia member which the latter resists, whereby the effect of lateral acceleration is reduced.

Abstract: A dip angle data transmitter wherein a laminated pendulum, housed in a viscous fluid completely filling a casing, is arranged in the latter so that the distance between the surfaces of the pendulum's plates and the inner surface of the casing is found from the following formula: ##EQU1## WHEREIN .chi. IS THE DISTANCE BETWEEN THE SURFACES OF THE PENDULUM PLATES AND THE INNER SURFACE OF THE CASING FOR THE GIVEN TWO POINTS;.nu. is the kinematic viscosity of the viscous fluid at a minimum working temperature;.omega. is the natural frequency of the transmitter oscillations; and g is the gravity acceleration.

Abstract: A measuring apparatus for determining the position of a roller apron of a continuous casting installation comprising at least one partially curved roller apron, wherein calibrated plumb bobs or lines can be applied to coordinate-measuring points of the roller apron for projecting the position of the measuring points in the x-axis or z-axis into a substantially horizontal measuring plane. Along the roller apron there are applied at a number of such coordinate-measuring points the calibrated plumb bobs or lines at the reference distance in the y-axis between the momentary or related measuring point and the measuring plane.

Abstract: A grade level comprising a hollow, fluid-tight cylindrical housing having its central axis normally disposed in a horizontal attitude. The housing comprises an annular wall portion and spaced-apart end members mounted on opposite sides thereof. A horizontally disposed shaft is mounted in the housing and extends between the end members and has a float-weight mechanism operatively rotatively mounted thereon. The mechanism comprises a float portion which extends upwardly from the shaft and a counterbalacing weight which extends downwardly from the shaft. A pair of baffles are secured to the annular wall portion at opposite sides thereof and extend substantially horizontally inwardly therefrom towards the shaft. A fluid is provided within the housing to dampen the movement of the mechanism as the housing is moved to various attitudes. A ballast material is provided in the weight portion to cause the mechanism to normally be positioned in an upright positive relative to horizontal.

Abstract: A hydraulic fluidic level sensor for detecting an angular deviation from vity vertical comprising an inverted pendulum in conjunction with two fluidic proximity sensors to provide an output signal proportional to the angular deviation. Opposing fluid jets from the fluidic proximity sensors impinge on the inverted pendulum shaft to produce a net jet force which counterbalances the pendulum moment due to gravity. The pressure signal output from the proximity sensors is proportional to the angular deviation from the vertical and provides the input signal to a level control system. A secondary pendulum damping system is used to provide necessary viscous damping.