Remote-indicating magnetic compass

• US 4,146,970 A
• Filed: 12/26/1973
• Issued: 04/03/1979
• Est. Priority Date: 12/26/1973
• Status: Expired due to Term

• Current Assignee: Robert A. Edwards
• Original Assignee: Robert A. Edwards
• Inventors: Edwards, Robert A.
• Primary Examiner(s): Aegerter, Richard E.
• Assistant Examiner(s): Shepperd, John W.
• Application Number:
  US05/428,460
• Time in Patent Office: 1,924 Days
• Field of Search: 33/363 K, 33/363 R, 33/312, 33/361, 33/366, 33/362, 33/356, 33/317, 33/325, 250/231 R, 250/231 SE, 250/237, 340/201 P, 340/27 NA, 324/175
• US Class Current: 33/363.00K
• CPC Class Codes: G01C 17/26 using electric pick-offs for transmission to final indicator, e.g. photocell

Abstract

A remote-indicating magnetic compass system for use with automobiles or the like. The system consists of a dashboard-mounted readout unit, which receives and decodes logic signals provided thereto from a remotely located electro-optical shaft encoder, the latter being responsive to and positioned by the earth'"'"'s magnetic field. The form of bearing readout is discrete rather than continuous, e. g. 8 or 16 bearing states are described. The bearing readout display may be defined by a plurality of discrete indicators, such as light-emitting diodes, or segmented alpha indicators or so forth may be employed. The electro-optical shaft encoder assembly is preferably located at a point on the vehicle distant from large bodies of iron or steel, and where the earth'"'"'s field is strong relative to fields associated with permanently magnetized auto parts.

Claims

1. A remote-indicating magnetic compass system for use by the general public in automobiles or the like comprising:

a housing;

a transparent viscous damping fluid filling said housing a compass magnet;

means rotatably mounting the magnet in the housing for response to the incident magnetic field of the earth;

compensation magnets in the vicinity of the compass for imposing an additional magnetic field to compensate for magnetic fields produced by an automobile;

an encoder coupled to the compass magnet having a single light modulating arc;

a continuous light source adjacent said encoder to illuminate said arc;

phototransistors arranged equally spaced on a circle parallel to the circle traversed by said arc such that single or adjacent pairs of phototransistors are illuminated by said light modulating arc;

light annunciators corresponding to the number of phototransistor mounted to a map scale to indicate auto heading relative to map letters N. W. W. E. and;

electric means directly connecting each phototransistor to a single light annunciator.

2. A remote-indicating magnetic compass system for use by the general public in automobiles or the like comprising;

a housing;

a transparent viscous damping fluid filling said housing;

a compass magnet;

means rotatably mounting the compass magnet in said housing for response to the incident magnetic fluid of the earth;

compensation magnets in the vicinity of said compass magnet for imposing an additional magnetic field to compensate for spurious magnetic fields produced by an automobile;

an encoder coupled to said compass magnet having a number of staggered arcs at different radial distances;

a continuous light source adjacent said encoder to illuminate said arcs;

phototransistor equal in number to the arcs arranged in a cluster such that each phototransistor senses only one arc;

a light annunciator for each phototransistor the light annunciators being mounted to a map scale to indicate auto heading relative to map letters N. S. E. W. and;

electric means directly connecting each phototransistor to its corresponding light annunciator.