US3854129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrasonic intrusion detection system
Assignee: Individual
•
Filing: 1973-07-19
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Granted: 1974-12-10
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Expires: 1993-07-19
Abstract
Abstract The disclosed system detects any change in the net crosssectional opening area between the inside and outside of an enclosed contiguous volumn. A slowly varying small cyclic pressure variation is generated within the protected volume by a small motor driving an oscillating piston or baffle located in a perimeter wall. As the piston moves back and forth air is moved through the existing leakage paths resulting in a fixed average power level required of the driving motor. Any change in the cross-sectional opening area or air leakage path will result in a change in the average power required to move the piston and this change in power level may be used to activate an alarm means.
Inventors
- 👤 F Haselton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:30
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/16; G08B13/1654; G08B13/1681
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
93 words
An infrasonic intrusion detector for use in a confined space comprising a. means for generating alternating infrasonic over and under pressure variations within a confined space, said pressure alternating with respect to ambient exterior pressure, b. means responsive to the atmpospheric resistance encountered by said generating means as said generating means generates pressure variations within said protected volume, c. detector means for detecting any change in the atmospheric resistance encountered by said responsive means, d. alarm means activated by said detecting means to provide an alarm signal upon a change in said resistance.
Claim 2
Dependent Claim
93 words
An infrasonic intrusion detector for use in a confined space comprising a. means for generating alternating infrasonic over and under pressure variations within a confined space, said pressure alternating with respect to ambient exterior pressure, b. means responsive to the atmpospheric resistance encountered by said generating means as said generating means generates pressure variations within said protected volume, c. detector means for detecting any change in the atmospheric resistance encountered by said responsive means, d. alarm means activated by said detecting means to provide an alarm signal upon a change in said resistance.
Claim 3
Dependent Claim
27 words
An infrasonic intrusion detector as claimed in claim 1 wherein said pressure generating means comprises a movable baffle positioned within a wall which defines said confined space.
Claim 4
Dependent Claim
21 words
An infrasonic intrusion detector as claimed in claim 2 wherein said space is a dwelling and said wall is a ceiling.
Claim 5
Dependent Claim
27 words
An infrasonic intrusion detector as claimed in claim 1 wherein said means for generating alternating pressure variations alternated at a rate less than 10 cycles per second.
Claim 6
Dependent Claim
37 words
An infransonic intrusion detector as claimed in claim 2 wherein said detector means comprise a resilient means mounted adjacent said baffle and connected to a dashpot which restrains said resilient means through a predetermined amplitude of excursion.
Claim 7
Dependent Claim
148 words
An infrasonic intrusion detector for use in protecting a confined space comprising a. movable baffle means mounted in a perimeter wall defining said confined space, said baffle generating alternating pressure variations within said space, b. motor means for moving said baffle, said motor means mounted on a reaction means which includes a resilient reaction element between said motor means and said perimeter wall, c. resilient contact means mounted on said reaction means, said contact means mounted adjacent a fixed contact means, said resilient contact being restrained by a dashpot means from engaging said fixed contact means during normal excursions of said baffle means, said resilient contact engaging said fixed contact when the amplitude of motion of said reaction element exceeds a predetermined distance, d. alarm signal means activated by the closing of said contacts to provide an alarm signal when said amplitude of motion exceeds a predetermined distance.
Claim 8
Dependent Claim
148 words
An infrasonic intrusion detector for use in protecting a confined space comprising a. movable baffle means mounted in a perimeter wall defining said confined space, said baffle generating alternating pressure variations within said space, b. motor means for moving said baffle, said motor means mounted on a reaction means which includes a resilient reaction element between said motor means and said perimeter wall, c. resilient contact means mounted on said reaction means, said contact means mounted adjacent a fixed contact means, said resilient contact being restrained by a dashpot means from engaging said fixed contact means during normal excursions of said baffle means, said resilient contact engaging said fixed contact when the amplitude of motion of said reaction element exceeds a predetermined distance, d. alarm signal means activated by the closing of said contacts to provide an alarm signal when said amplitude of motion exceeds a predetermined distance.
Claim 9
Dependent Claim
21 words
An infrasonic intrusion detector as claimed in claim 6 wherein said space is a dwelling and said wall is a ceiling.
Claim 10
Dependent Claim
26 words
An infrasonic intrusion detector as claimed in claim 6 wherein said baffle means generates alternating pressure variations at a rate less than 10 cycles per second.
Claim 11
Dependent Claim
93 words
An infrasonic intrusion detector for use in a confined space comprising, a. means of generating alternating infrasonic over and under pressure variations within a confined space, said pressure alternating with respect to ambient exterior pressure, b. means for monitoring the power required to create the pressure differential encountered by said alternating pressure generating means, c. detecting means for detecting any change in the average power required to drive said alternating pressure means and, d. alarm means actuated by said detecting means to provide an alarm signal upon a change in said power level.
Claim 12
Dependent Claim
93 words
An infrasonic intrusion detector for use in a confined space comprising, a. means of generating alternating infrasonic over and under pressure variations within a confined space, said pressure alternating with respect to ambient exterior pressure, b. means for monitoring the power required to create the pressure differential encountered by said alternating pressure generating means, c. detecting means for detecting any change in the average power required to drive said alternating pressure means and, d. alarm means actuated by said detecting means to provide an alarm signal upon a change in said power level.
Claim 13
Dependent Claim
49 words
An infrasonic intrusion detector as claimed in claim 9 wherein said means for generating alternating pressure variations comprises a movable baffle, and said detecting means comprises a resilient means mounted on said baffle and connected to a dashpot which restrains said resilient means through a predetermined amplitude of excursion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |