US4005938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Horizon indicating device for marine sextant
Assignee: Individual
•
Filing: 1975-09-05
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Granted: 1977-02-01
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Expires: 1995-09-05
Abstract
Abstract A horizon indicating device adapted to be mounted behind the horizon glass of a conventional marine sextant, comprising a wire indicator which is kept always in a horizontal position with two sets of pivotal axis forming a two dimensional universal support to cope with a rolling and pitching ship. The said device enables the sextant to function normally under poor visibility when the real horizon can not be seen. The self-illuminated wire indicator makes the sextant being able also to work during night time.
Inventors
- 👤 Shiaw-Lei Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:12
CPC Classifications
G; G01; G01C; G01C1/00; G01C1/08; G01C1/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
215 words
In a marine sextant having a main frame carrying a telescope and a horizon glass, the improvement comprising means between said telescope and horizon glass for simulating a real horizon to compensate for poor visibility and rough seas, said horizon simulating means comprising: a first U-shaped bracket having upwardly extending arms, a second U-shaped bracket having upwardly extending arms, the bottom portions of said first and second brackets being secured together, with said brackets arranged at 90° relative to one another; said first U-shaped bracket having one of its arms pivotably mounted to the center of the horizon glass, and the other of its arms pivotably mounted to a vertically upstanding support on the main frame of the sextant, to define a first axis of rotation; a pair of bubble level assemblies pivotably mounted to the arms of said second U-shaped bracket to define a second axis of rotation; each bubble level assembly including a counterbalancing screw at one end; a luminous wire of zig-zag shape having its ends mounted on said bubble level assemblies; said wire being oriented to simulate a real horizon on said horizon glass when viewed through said telescope; said wire being rotatable about said first and second axes of rotation to compensate for pitching and rolling movements of a ship.
Claim 2
Dependent Claim
215 words
In a marine sextant having a main frame carrying a telescope and a horizon glass, the improvement comprising means between said telescope and horizon glass for simulating a real horizon to compensate for poor visibility and rough seas, said horizon simulating means comprising: a first U-shaped bracket having upwardly extending arms, a second U-shaped bracket having upwardly extending arms, the bottom portions of said first and second brackets being secured together, with said brackets arranged at 90° relative to one another; said first U-shaped bracket having one of its arms pivotably mounted to the center of the horizon glass, and the other of its arms pivotably mounted to a vertically upstanding support on the main frame of the sextant, to define a first axis of rotation; a pair of bubble level assemblies pivotably mounted to the arms of said second U-shaped bracket to define a second axis of rotation; each bubble level assembly including a counterbalancing screw at one end; a luminous wire of zig-zag shape having its ends mounted on said bubble level assemblies; said wire being oriented to simulate a real horizon on said horizon glass when viewed through said telescope; said wire being rotatable about said first and second axes of rotation to compensate for pitching and rolling movements of a ship.
Claim 3
Dependent Claim
56 words
Apparatus according to claim 1 wherein said first bracket carries a first vertical pin extending through said first axis, at least one of said upstanding support and said horizon glass including first stopper studs positioned adjacent said first axis to engage said first pin for limiting the swing angle of said first bracket to ± 45°.
Claim 4
Dependent Claim
53 words
Apparatus according to claim 1 wherein each bubble level assembly includes a sound vertical pin extending through said second axis, the arms of said second bracket each including second stopper studs positioned adjacent said second axis to engage said second pin for limiting the swing angle of said second bracket to ± 45°.
Claim 5
Dependent Claim
126 words
Apparatus according to claim 1 wherein said first bracket carries a first vertical pin extending through said first axis, at least one of said upstanding support and said horizon glass including first stopper studs positioned adjacent said first axis to engage said first pin for limiting the swing angle of said first bracket to ± 45°; each bubble level assembly including a second vertical pin extending through said second axis, the arms of said second bracket each including second stopper studs positioned adjacent said second axis to engage said second pin for limiting the swing angle of said second bracket to ± 45°; said wire including a projecting portion and recessed portions on opposite sides thereof spaced further from said horizon glass than said projecting portion.
Claim 6
Dependent Claim
117 words
Apparatus according to claim 4 wherein said horizon glass comprises a metal ring and integral base, said base being secured to the main frame of said sextant; said ring including holding screws for supporting a glass portion, said glass portion comprising a reflecting glass section occupying more than one-half of the area of said glass portion, a transparent glass section adjacent said reflecting glass section, and a metal plate covering an end of said transparent glass section which is remote from said reflecting glass section; said reflecting glass section being provided with a metal backing; said metal backing and said metal plate carrying adjustment means for varying the vertical positioning of said reflecting and transparent glass sections.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-02-01 | 1980-08-02 | 1981-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-01 | 1984-08-02 | 1985-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-01 | 1988-08-02 | 1989-02-01 | $7700.00 | Window Closed / Lapsed |