US3905707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical level
Assignee: Individual
•
Filing: 1974-06-07
•
Granted: 1975-09-16
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Expires: 1994-06-07
Abstract
Abstract An optical level has at least two windows respectively serving as entrance aperture and exit aperture for a beam of light. The optical level can assume two positions of use and receives three media of different densities that do not blend with each other. The volume of the medium of the greatest density is equal to the volume of the medium of the smallest. According to the position of the optical level, the beam of light is reflected at least once by the bounding surface between the medium of medial density and the medium of the greatest density or by the bounding surface between the medium of medial density and the medium of the smallest density. The beam of light can also be reflected by the interior wall of the level.
Inventors
- 👤 Wieland Feist
- 👤 Hans-Joachim Stachel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:21
CPC Classifications
G; G01; G01C; G01C9/00; G01C9/18
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
161 words
An optical level for determining verticality comprising a housing, said housing being completely filled with three nonmiscible fluid media of different densities each of said media occupying corresponding one of three vertically spaced zones of said housing and defining horizontal bounding surfaces between adjacent zones, at least two transparent windows in the housing for the entrance and exit of a beam of light, said housing having a reference axis, said windows, in a position of the housing in which said reference axis is vertical, opening to and exiting from a central one of said three zones whereby a beam of light passing through said windows is propagated exclusively in said central zone, and said windows being inclined to and symmetrically disposed about said reference axis in said position, said medium of the least density and the medium of the greatest density having equal volumes and occupying upper and lower ones of said zones respectively and sandwiching the medium of medial density.
Claim 2
Dependent Claim
161 words
An optical level for determining verticality comprising a housing, said housing being completely filled with three nonmiscible fluid media of different densities each of said media occupying corresponding one of three vertically spaced zones of said housing and defining horizontal bounding surfaces between adjacent zones, at least two transparent windows in the housing for the entrance and exit of a beam of light, said housing having a reference axis, said windows, in a position of the housing in which said reference axis is vertical, opening to and exiting from a central one of said three zones whereby a beam of light passing through said windows is propagated exclusively in said central zone, and said windows being inclined to and symmetrically disposed about said reference axis in said position, said medium of the least density and the medium of the greatest density having equal volumes and occupying upper and lower ones of said zones respectively and sandwiching the medium of medial density.
Claim 3
Dependent Claim
55 words
An optical level as claimed in claim 1 wherein the housing includes at least one reflecting surface for reflecting a beam of light between the light entrance window and the light exit window, said reflecting surface being disposed in said central zone in that position of the housing in which the reference axis is vertical.
Claim 4
Dependent Claim
34 words
An optical level as claimed in claim 1 wherein the central zone of said housing, in that position of the housing in which said reference axis is vertical, is of substantially trapezoidal cross section.
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) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |