US3825916A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser fence
Assignee: California Crime Technological Research Foundation
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Filing: 1972-10-20
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Granted: 1974-07-23
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Expires: 1992-10-20
Abstract
Abstract First and second transmitting stations provide two, parallel, line-of-sight, pulsed beams of infrared energy generated from a solid state source. The (laser) beams are intercepted by corresponding receiving stations. The two line of sight beams are displaced horizontally and vertically from each other; and by orienting the beams along a perimeter to be protected, any invasion of the perimeter is sensed by interruption of the beams. Detection of animals, such as dogs, is negated by logic circuitry affording height discrimination. The circuitry also discriminates with respect to man parameters, such as man''s usual forward velocity, namely, approximately 1/2 feet per second to 10 feet per second. False alarms from flying birds, leaves and the like, are thereby minimized. Intrusions can be indicated by audible and visual local alarms, or, if desired, by automatic telephone dialing, radio or closed circuit TV to more distant centers. By using additional stations and corner reflectors, where appropriate, a continuous chain is constructed to enclose an area to be guarded.
Inventors
- 👤 R Steele
- 👤 D Roudabush
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:07
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/181; G08B13/183
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
349 words
A laser security fence comprising: a. a first laser beam transmitting station including a first pulsed laser beam generator oriented so as to direct said first beam substantially on a first line of sight along a perimeter to be protected; b. a first laser beam receiving station located substantially on said first line of sight at a distance from said first laser beam transmitting station at least on the order of one hundred feet, or more, and oriented so as to intercept said first beam from said first transmitting station, said first receiving station being capable of detecting interruptions in said first beam; c. a second laser beam transmitter station adjacent said first laser beam receiving station including a second pulsed laser beam substantially on a second line of sight along the perimeter to be protected, said first line of sight being substantially parallel to said second line of sight, displaced approximately two feet above the horizontal plane of said second line of sight, and displaced approximately three feet laterally from the vertical plane of said second line of slight; d. a second laser beam receiving station adjacent said first laser beam transmitting station substantially on said second line of sight and oriented so as to intercept said second beam from said second transmitting station, said second receiving station being capable of detecting interruptions in said second beam; e. logic means connected to said first and said second receiving stations for discriminating between predetermined sequences and durations of interruption signals attributed to invasion by a physical body having man parameters of height and velocity, said logic means being programmed to discriminate the man parameter of forward velocity ranging between a slow walking speed of about two feet per second and a running speed of about ten feet per second based upon the intervals between the interruptions of said first and said second beams, and by physical bodies not having said man parameters; and, f. warning means connected to said logic means for alerting security personnel in the event of indicated invation by a physical body having said man parameters.
Claim 2
Dependent Claim
349 words
A laser security fence comprising: a. a first laser beam transmitting station including a first pulsed laser beam generator oriented so as to direct said first beam substantially on a first line of sight along a perimeter to be protected; b. a first laser beam receiving station located substantially on said first line of sight at a distance from said first laser beam transmitting station at least on the order of one hundred feet, or more, and oriented so as to intercept said first beam from said first transmitting station, said first receiving station being capable of detecting interruptions in said first beam; c. a second laser beam transmitter station adjacent said first laser beam receiving station including a second pulsed laser beam substantially on a second line of sight along the perimeter to be protected, said first line of sight being substantially parallel to said second line of sight, displaced approximately two feet above the horizontal plane of said second line of sight, and displaced approximately three feet laterally from the vertical plane of said second line of slight; d. a second laser beam receiving station adjacent said first laser beam transmitting station substantially on said second line of sight and oriented so as to intercept said second beam from said second transmitting station, said second receiving station being capable of detecting interruptions in said second beam; e. logic means connected to said first and said second receiving stations for discriminating between predetermined sequences and durations of interruption signals attributed to invasion by a physical body having man parameters of height and velocity, said logic means being programmed to discriminate the man parameter of forward velocity ranging between a slow walking speed of about two feet per second and a running speed of about ten feet per second based upon the intervals between the interruptions of said first and said second beams, and by physical bodies not having said man parameters; and, f. warning means connected to said logic means for alerting security personnel in the event of indicated invation by a physical body having said man parameters.
References Cited (Backward Citations)
US2082941A
Cited
US2653309A
Cited
US3036219A
Cited
US3183499A
Cited
US3242341A
Cited
US3370285A
Cited
US3524180A
Cited
US3641549A
Cited
US3711846A
Cited
US3723738A
Cited
US3739372A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |