US3821558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination or monitoring of the distances of surfaces from reference positions
Assignee: FLEET ELECTRONICS Ltd
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Filing: 1972-08-09
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Granted: 1974-06-28
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Expires: 1992-08-09
Abstract
Abstract In an apparatus for monitoring the height to which material has been filled into commodity packages, the level of the top surface of the material in each package is determined, without physical contact between the apparatus and the material, by traversing a light beam across said top surface and generating a signal when the spot of light on said top surface intersects the viewing beam or beams of one or more photoelectric detector cells. The light beam and the viewing beam lie in a common plane but have different angular directions, at least at the instant of intersection. The point in the light beam traverse cycle at which intersection with the viewing beam takes place therefore varies in time according to the level of the top surface of the material in the package and so gives a measure of that level.
Inventors
- 👤 J Brian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:36
CPC Classifications
G; G01; G01C; G01C3/00; G01C3/10; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G01F23/2921; G01F23/2928
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
164 words
Apparatus to monitor the top surface level of fluent material in a container, comprising a light source and projection means to project at least one beam of light therefrom downwardly on to the horizontal surface of said fluent material thereby to create at least periodically a sensible spot on said surface where the light beam impinges, and two photocells mounted to view said surface from above along mutually oblique viewing axes lying in a common vertical plane in which lies also said sensible spot, and wherein said projection means comprises a rotary optical assembly causing said light beam to sweep angularly repeatedly substantially in said plane at a substantially uniform rate whereby said spot repeatedly travels across said surface from a point in the viewing axis of one said photocell to a point in the viewing axis of the other, and circuitry is provided that measures the interval between the occurrences of sensing of said spot by said two photocells during an individual sweep.
Claim 2
Dependent Claim
164 words
Apparatus to monitor the top surface level of fluent material in a container, comprising a light source and projection means to project at least one beam of light therefrom downwardly on to the horizontal surface of said fluent material thereby to create at least periodically a sensible spot on said surface where the light beam impinges, and two photocells mounted to view said surface from above along mutually oblique viewing axes lying in a common vertical plane in which lies also said sensible spot, and wherein said projection means comprises a rotary optical assembly causing said light beam to sweep angularly repeatedly substantially in said plane at a substantially uniform rate whereby said spot repeatedly travels across said surface from a point in the viewing axis of one said photocell to a point in the viewing axis of the other, and circuitry is provided that measures the interval between the occurrences of sensing of said spot by said two photocells during an individual sweep.
Claim 3
Dependent Claim
46 words
Apparatus according to claim 1, wherein said rotary optical assembly is a rotary drum assembly surrounding the light source and having one or more lenses set in its peripheral wall, the axis of rotation of the drum being perpendicular to said plane containing the photocell axes.
Claim 4
Dependent Claim
93 words
Apparatus according to claim 1, wherein the repeatedly sweeping beam is generated by said rotary optical assembly rotating about an axis parallel to the path of the beam from the light source thereto and also substantially parallel to the line bisecting the angle between the viewing axes of the photocells, the sweeping being performed by a similarly parallel beam reflected from an optical element of said rotary assembly which, during the sweeping is travelling in a short arc of its rotary path which is roughly parallel to the plane of the photocell axes.
Claim 5
Dependent Claim
64 words
Apparatus according to claim 3, wherein said rotary optical assembly comprises a central reflecting optical element reflecting the beam from the light source into a path substantially parallel to the plane of rotation, and least one further reflecting optical element rotating around said central element in planetary fashion and serving to reflect the beam into a path substantially parallel to the axis of rotation.
Claim 6
Dependent Claim
51 words
Apparatus according to claim 3, further comprising a disc rotating with said optical assembly and bearing at least one set sets of equiangularly spaced peripheral indicia which are viewed by an auxiliary photoelectric detector as they pass thereby to set up trains of regularly timed signal pulses as the disc rotates.
Claim 7
Dependent Claim
69 words
Apparatus according to claim 5, wherein said pulse trains are each gated by consecutive pulses from the two photocells indicating the beginning and end of the passage of the scanning beam over the path between the points where the two photocell viewing axes intersect the scanned surface, thereby to pass a variable portion of each pulse train containing a number of pulses indicative of the length of said path.
Claim 8
Dependent Claim
32 words
Apparatus according to claim 5, wherein the digital signal constituted by each portion of a pulse train passed as aforesaid is subjected to a digital-to-analogue conversion for read-out and level detection purposes.
Claim 9
Dependent Claim
69 words
Apparatus according to claim 1, wherein consecutive pulses from the two photocells are applied to set and reset, respectively, a bistable circuit whereby the output of the bistable circuit constitutes a switching signal that is present for a variable time period representative of the time taken for the sweeping beam to traverse the path between the points of intersection of the two photocell viewing axes with the scanned surface.
Claim 10
Dependent Claim
23 words
Apparatus according to claim 1, wherein the light source is provided with interchangeable imaging lenses to suit the nature of the swept surface.
Claim 11
Dependent Claim
16 words
Apparatus according to claim 1, wherein the rotary assembly is driven by a synchronous electric motor.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |