Dual readout analog/digital magnetic compass

Claim 2

A magnetic compass comprising: a housing including housing reference direction means, a first disk contained within said housing, said disk being a permanently magnetized disk rotatably mounted upon a nonpermeable shaft disposed between jeweled bearings centered and aligned on opposite sides of said housing, said shaft having at each end sharp points acting as pivot points, so as to be freely rotatable within said housing, said first disk having a top surface and a bottom surface, the top surface of said first disk having a compass dial imprinted thereon with the north direction of said compass dial oriented to correspond to the direction of the magnetization of said disk, the housing adjacent to the top surface of said first disk beinq made of visually transparent material allowing the compass dial to be read in analog fashion, a second disk, being transparent and contained within said housing and affixed to said shaft, said second disk being disposed in opposition to the bottom surface of said first disk, said shaft being freely rotatable within said housing so that said disks are freely rotatable about the common axis of rotation of said disks, a read head comprising a light emitter and a light receptor positioned on opposite sides of said second disk in light receptive orientation, a light source, a light detector capable of generating output voltage proportional to the intensity of the light received by said detector, means for modulating the intensity of the light transmitted by said second disk in a manner that unambiguously relates said intensity to the angular displacement of the two disks relative to the reference direction, optical fibers connecting said light source to said emitter, optical fibers connecting said receptor to said detector, electronic circuitry capable of converting said output voltages to a digital display whereby the angular displacement of the magnetized disk with respect to the housing may be displayed, thereby providing a readout of the compass heading, electrical connection between the light detectors and said electronic circuitry, and electrically conducting matter disposed in a closed surface enclosing said circuitry, with said first disk positioned outside said surface, the electrically conducting matter being of sufficient conductivity and thickness to electrically shield said first disk from the electrical influence of said circuitry.

Claim 3

A dual readout analog/digital magnetic compass, being a compass according to claim 1 wherein the second disk is constructed of optically transparent material and has imprinted thereon binary coded digital opaque markings whereby the light transmitted by said disk is modulated in a digital manner causing the said output voltages to be digitized whereby the angular displacement of the said disks relative to said housing is displayed by the readout in a digital display.

Claim 4

A magnetic compass according to claim 1 wherein said second disk is constructed of transparent material upon which is imprinted opaque material masking a transparent iris through said second disk, the edges of said iris being a figure having a first radial edge and a second radial edge located radially opposite said first radial edge, each said radial edge having an inner end and an outer end, and two generally concentric edges being an outer edge and an inner edge, the outer edge connecting the outer ends of the two radial edges and the inner edge connecting the inner ends of the two radial edges, the generally concentric edges being tapered in the radial direction with respect to angular displacement about the axis of said disk, an optical read head comprising a ribbon shaped light-transmissive fiber optic input terminal disposed on one side of said disk and a congruently shaped light-transmissive fiber optic output terminal disposed in light receptive position on the other side of said disk, said terminals being aligned along a radius of said disk, with said input terminal connected to a light source by an optical fiber and said output terminal connected to a photodetector by a ribbon shaped optical fiber, said photodetector being capable of generating an output voltage proportional to the intensity of the light received by said photodetector, thereby resulting in an output voltage from said read head that varies in continuous fashion as the second disk rotates, and means for converting said output voltage to a digital readout display.

Claim 5

A magnetic compass and inclinometer, comprising a magnetic compass according to claim 1 wherein is included an inclinometer comprising a third disk rotatably mounted so as to rotate freely about its central axis, said axis being disposed orthogonal to the shaft connecting first disk to second disk and orthogonal to the plane containing said shaft and the housing reference direction, said third disk having a first hemidisk and a second hemidisk, said first and second hemidisks being disposed on opposite sides of a diameter of said third disk, a reference radius of said third disk being disposed orthogonal to said diameter and lying within said first hemidisk, means to cause said third disk to automatically orient itself so that the reference radius is vertical when the housing is oriented with the central axis of said third disk horizontal and so that said first hemidisk is disposed above said central axis with respect to the center of the earth, means to sense and read out the angular displacement of the housing from the reference radius of said third disk.

Claim 6

A magnetic compass according to claim 4 wherein said means to sense and read out the angular displacement of the housing from said reference radius of said third disk comprises analog angular information imprinted upon said first hemidisk and means to observe said analog information visually, second hemidisk being constructed of optically transparent material, binary coded digital opaque markings imprinted upon said second hemidisk, second optical read head disposed about said second hemidisk in a radial configuration, said second optical read head comprising a plurality of input and output optical fibers with ends positioned on opposite sides of said third disk in two linear arrays in light receptive orientation, the input optical fibers being connected to a light source and the output optical fibers being connected to light detectors capable of generating output voltages proportional to the intensity of the light received by said detectors, said third disk being provided with means for modulating the intensity of the light transmitted by said third disk to the output optical fibers in a manner that unambiguously relates said intensity to the angular displacement of said third disk relative to said housing, electronic circuitry capable of converting the output of said second optical readhead to a digital display whereby the angular displacement of said third disk with respect to the housing may be displayed, electrical connection between the output of said second readhead and said circuitry.

Claim 7

A magnetic compass according to claim 4 wherein the means to sense and read out the angular displacement of the housing from the reference radius of said third disk comprises said third disk being constructed of transparent material upon which is imprinted opaque material masking a transparent iris through said third disk, the edges of said iris being a figure having a first radial edge and a second radial edge located radially opposite said first radial edge, each said radial edge having an inner end and an outer end, and two generally concentric edges being an outer edge and an inner edge, the outer edge connecting the outer ends of the two radial edges and the inner edge connecting the inner ends of the two radial edges, the generally concentric edges being tapered in the radial direction with respect to angular displacement about the axis of said third disk, an optical read head comprising a ribbon shaped light-transmissive fiber optic input terminal disposed on one side of said third disk and a congruently shaped light-transmissive fiber optic output terminal disposed in light receptive position on the other side of said third disk, said terminals being aligned along a radius of said third disk, with said input terminal connected to a light source by an optical fiber and said output terminal connected to a photodetector by a ribbon shaped optical fiber, said photodetector being capable of generating an output voltage proportional to the intensity of the light received by said photodetector, thereby resulting in an output voltage from said read head that varies in continuous fashion as said third disk rotates, and means for converting said output voltage to a digital readout display.

Claim 8

A magnetic compass comprising a housing containing a damping liquid therein and including: a disk having an upper surface and a lower surface, rotatably mounted so as to rotate freely, having a compass dial imprinted on the upper surface, a magnet affixed to said disk and disposed therewith so as to align said disk with respect to the earth's magnetic field, the part of said housing above said compass dial being visually transparent, said lower surface being disposed of reflective and absorptive areas representative of the angular position about the axis of rotation of said disk wherein binary coded digital markings are imprinted upon the lower surface of said disk, encoding the compass headings of said disk, the said markings being light-absorptive, the remainder of said lower surface being optically reflective, a reflecting optical read head disposed adjacent to the bottom surface of said disk and comprising two parallel linear arrays of a multiplicity of optical fiber terminals, said linear arrays being disposed parallel to a radius of said disk, said arrays being an emitting array and a receiving array, each array being inclined toward the center line between the two arrays at such angle that light emitted by a terminal of an optical fiber in the emitting array will be reflected by the lower surface of said disk into the adjacent optical fiber terminal in the receiving array if a reflective area of said disk is positioned opposite the emitting fiber whereas said light will be absorbed if a light-absorptive marking is positioned opposite the said terminal, a light source with power source therefore included therein, a multiplicity of optical fibers connecting the terminals of the optical fibers in said emitting array to said light source and the receiving array being connected by optical fibers to a multiplicity of light sensors for sensing the code marked on the lower surface of the disk, means for converting the received light into electrical signals representative of the compass heading, electronic circuitry, including a source of electrical power and a digital readout display, capable of producing a digital readout display of the compass heading, and means for transmitting said electrical signals representative of the compass heading to said electronic circuitry.

Claim 9

A magnetic compass comprising a housing containing a damping liquid therein and including: a disk having an upper surface and a lower surface, rotatably mounted so as to rotate freely, having a compass dial imprinted on the upper surface, a magnet affixed to said disk and disposed therewith so as to align said disk with respect to the earth's magnetic field, the part of said housing above said compass dial being visually transparent, said lower surface being disposed of reflective and absorptive areas representative of the angular position about the axis of rotation of said disk wherein binary coded digital markings are imprinted upon the lower surface of said disk, encoding the compass headings of said disk, the said markings being light-absorptive, the remainder of said lower surface being optically reflective, a reflecting optical read head disposed adjacent to the bottom surface of said disk and comprising two parallel linear arrays of a multiplicity of optical fiber terminals, said linear arrays being disposed parallel to a radius of said disk, said arrays being an emitting array and a receiving array, each array being inclined toward the center line between the two arrays at such angle that light emitted by a terminal of an optical fiber in the emitting array will be reflected by the lower surface of said disk into the adjacent optical fiber terminal in the receiving array if a reflective area of said disk is positioned opposite the emitting fiber whereas said light will be absorbed if a light-absorptive marking is positioned opposite the said terminal, a light source with power source therefore included therein, a multiplicity of optical fibers connecting the terminals of the optical fibers in said emitting array to said light source and the receiving array being connected by optical fibers to a multiplicity of light sensors for sensing the code marked on the lower surface of the disk, means for converting the received light into electrical signals representative of the compass heading, electronic circuitry, including a source of electrical power and a digital readout display, capable of producing a digital readout display of the compass heading, and means for transmitting said electrical signals representative of the compass heading to said electronic circuitry.

Claim 10

A magnetic compass comprising: a housing, a disk contained within said housing, said disk being a permanently magnetized disk rotatably mounted upon a non-permeable shaft disposed between jeweled bearings centered and aligned on opposite sides of said housing, said shaft having at each end sharp points acting as pivot points, so as to be freely rotatable within said housing, said disk having a top surface and a bottom surface, the top surface of said disk having a compass dial imprinted thereon with the north direction of said compass dial oriented to correspond to the direction of the magnetization of said disk, the housing adjacent to the top surface of said first disk being made of visually transparent material allowing the compass dial to be visually read in analog fashion, the bottom surface of said disk being composed of light-reflective material covered with non-reflective material except for a portion thereof whereat an open iris exposes said reflective material, the edges of said iris being a figure having a first radial edge and a second radial edge located radially opposite said first radial edge, each said radial edge having an inner end and an outer end, and two generally concentric edges being an outer edge and an inner edge, the outer edge connecting the outer ends of the two radial edges and the inner edge connecting the inner ends of the two radial edges, the generally concentric edges being tapered in such manner that the width of the iris in the radial direction is a monotonic function of angular position about the axis of the disk, an optical read head comprising an emitter terminal and a receptor terminal, each of said terminals being composed of light-transmissive optic fiber material with a planar face, said faces each being rectangular in shape having two long sides and two short sides, the long sides being sensibly longer than the maximum width of the iris and the short sides being small compared to said maximum width, said terminals being disposed with their long sides side by side to each other and in a radial direction with respect to the disk and in opposition to the lower surface of said disk and positioned so that the separation between said lower surface and the terminals is small compared to the short sides of said terminals with the planar faces of said terminals facing toward the disk and inclined toward each other in the plane perpendicular to the long sides at such angle that light emitted from the emitter terminal will be reflected into the receptor terminal by the exposed reflective surface within the iris with a fence-shaped baffle positioned along the vertex formed by said terminals and extending perpendicular to the plane of the disk, said baffle being as long as the long sides of said terminals and extending in height in the direction toward said disk to such distance that it shields the receptor terminal from light emitted by the emitter terminal, an optical fiber connecting the emitter terminal in light-transmissive manner with a light source with power therefore contained within the housing, an optical fiber connecting the receptor terminal in light-transmissive manner with a photodetector capable of generating an output voltage proportional to the intensity of light received by said photodetector, means for converting said output voltage to a digital readout display representative of the compass heading.

Claim 11

A magnetic compass comprising: a housing, a disk contained within said housing, said disk being a permanently magnetized disk rotatably mounted upon a non-permeable shaft disposed between jeweled bearings centered and aligned on opposite sides of said housing, said shaft having at each end sharp points acting as pivot points, so as to be freely rotatable within said housing, said disk having a top surface and a bottom surface, the top surface of said disk having a compass dial imprinted thereon with the north direction of said compass dial oriented to correspond to the direction of the magnetization of said disk, the housing adjacent to the top surface of said first disk being made of visually transparent material allowing the compass dial to be visually read in analog fashion, the bottom surface of said disk being composed of light-reflective material covered with non-reflective material except for a portion thereof whereat an open iris exposes said reflective material, the edges of said iris being a figure having a first radial edge and a second radial edge located radially opposite said first radial edge, each said radial edge having an inner end and an outer end, and two generally concentric edges being an outer edge and an inner edge, the outer edge connecting the outer ends of the two radial edges and the inner edge connecting the inner ends of the two radial edges, the generally concentric edges being tapered in such manner that the width of the iris in the radial direction is a monotonic function of angular position about the axis of the disk, an optical read head comprising an emitter terminal and a receptor terminal, each of said terminals being composed of light-transmissive optic fiber material with a planar face, said faces each being rectangular in shape having two long sides and two short sides, the long sides being sensibly longer than the maximum width of the iris and the short sides being small compared to said maximum width, said terminals being disposed with their long sides side by side to each other and in a radial direction with respect to the disk and in opposition to the lower surface of said disk and positioned so that the separation between said lower surface and the terminals is small compared to the short sides of said terminals with the planar faces of said terminals facing toward the disk and inclined toward each other in the plane perpendicular to the long sides at such angle that light emitted from the emitter terminal will be reflected into the receptor terminal by the exposed reflective surface within the iris with a fence-shaped baffle positioned along the vertex formed by said terminals and extending perpendicular to the plane of the disk, said baffle being as long as the long sides of said terminals and extending in height in the direction toward said disk to such distance that it shields the receptor terminal from light emitted by the emitter terminal, an optical fiber connecting the emitter terminal in light-transmissive manner with a light source with power therefore contained within the housing, an optical fiber connecting the receptor terminal in light-transmissive manner with a photodetector capable of generating an output voltage proportional to the intensity of light received by said photodetector, means for converting said output voltage to a digital readout display representative of the compass heading.

Claim 12

A magnetic compass according to claim 8 wherein said photodetector is a photocell.

Claim 13

A magnetic compass according to claim 8 wherein said photodetector is a solar cell.