US3841766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light curtain for accident prevention
Assignee: Individual
•
Filing: 1973-06-27
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Granted: 1974-10-15
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Expires: 1993-06-27
Abstract
Abstract Light curtain apparatus for accident prevention comprising: a pair of scanners disposed opposite one another, each scanning a respective predetermined area around an axis located in the scanner with a beam of light and each being associated with a respective one of a pair of opposed reflectors such that each beam of light is reflected back on itself independently of the angle of incidence; each scanner having installed therein a photoelectric transducer which, in the absence of any obstacle in the path of the associated beam of light, receives the light returned by the reflector and converts it into an electrical signal, any interruption in the electrical signal serving as an indication of an obstacle present in the beam of light; the two scanning areas each being in the form of a right-angled triangle and said triangles being contiguous.
Inventors
- 👤 A Walter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:02
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/12; F16P3/14; F16P3/144
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
139 words
Light curtain apparatus for accident prevention comprising: a pair of scanners disposed opposite one another, each scanning a respective predetermined area around an axis located in the scanner with a beam of light and each being associated with a respective one of a pair of opposed reflectors such that each beam of light is reflected back on itself independently of the angle of incidence; each scanner having installed therein a photoelectric transducer which, in the absence of any obstacle in the path of the associated beam of light, receives the light returned by the reflector and converts it into an electrical signal, any interruption in the electrical signal serving as an indication of an obstacle present in the beam of light; the two scanning areas each being in the form of a right-angled triangle and said triangles being contiguous.
Claim 2
Dependent Claim
139 words
Light curtain apparatus for accident prevention comprising: a pair of scanners disposed opposite one another, each scanning a respective predetermined area around an axis located in the scanner with a beam of light and each being associated with a respective one of a pair of opposed reflectors such that each beam of light is reflected back on itself independently of the angle of incidence; each scanner having installed therein a photoelectric transducer which, in the absence of any obstacle in the path of the associated beam of light, receives the light returned by the reflector and converts it into an electrical signal, any interruption in the electrical signal serving as an indication of an obstacle present in the beam of light; the two scanning areas each being in the form of a right-angled triangle and said triangles being contiguous.
Claim 3
Dependent Claim
37 words
Apparatus according to claim 1, wherein the respective reflectors are parallel with one another and the scanners are offset relative to one another, each being located at the end of the reflector associated with the other scanner.
Claim 4
Dependent Claim
59 words
Apparatus accordIng to claim 1, wherein the scanning movements of the two scanners are co-ordinated with one another in such a way that one scanner begins scanning at the common boundary line between the two areas and continues in an outward direction and the other scanner starts scanning at the outside and continues in a direction towards said boundary.
Claim 5
Dependent Claim
33 words
Apparatus according to claim 3, wherein the rotary movement of the light beam coming from the second scanner coincides in time with rotary movement of the light beam coming from the first scanner.
Claim 6
Dependent Claim
36 words
Apparatus according to claim 4, wherein in each scanner there is a further photoelectric transducer which is so designed and orientated that it receives the beam from the opposite scanner in its starting and finishing position.
Claim 7
Dependent Claim
21 words
Apparatus according to claim 5, wherein a starting and finishing signal is generated in each scanner by said further photoelectric transducer.
Claim 8
Dependent Claim
15 words
Apparatus according to claim 1, wherein lasers are employed as light sources in the scanners.
Claim 9
Dependent Claim
11 words
Apparatus according to claim 1, wherein said reflectors are triple reflectors.
Claim 10
Dependent Claim
32 words
Apparatus according to claim 8, wherein the two scanning areas comprise a rectangular scanning field and the triple reflectors permit scanning angles up to 22*, giving a distance aspect ratio of 10:4.
Claim 11
Dependent Claim
30 words
Apparatus according to claim 1, wherein the reflectors consist of individual parts which are inclined to an increasing degree to meet the changing angle of incidence of the rotary beam.
References Cited (Backward Citations)
US3360654A
Cited
US3619630A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |