US5117220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glass breakage detector
Assignee: Pittway Corp
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Filing: 1991-02-11
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Granted: 1992-05-26
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Expires: 2011-02-11
Abstract
Abstract A glass breakage detector utilizes a single microphone or piezoelectric element as a transducer to detect both the structurally-transmitted vibrations and airborne sounds indicative of breaking glass. The structurally transmitted component and airborne component are combined in accordance with a time-dependent function to provide an indication of breaking glass which has a low false alarm rate.
Inventors
- 👤 Francis C. Marino
- 👤 Stanley B. Freeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:15
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/04; G08B13/16; G08B13/1654; G08B13/1672
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
83 words
A method of detecting breaking glass comprising: detecting by said transducer means structurally-transmitted vibrations of impact on glass for generating a first signal; gating a circuit in said transducer means responsive to said first signal to enable detection by said transducer means of airborne-transmitted sounds; detecting by said transducer means airborne-transmitted sounds emitted by breaking glass for generating a second signal; and combining said first and second signals in accordance with a time-dependent function to generate an alarm signal indicative of breaking glass.
Claim 2
Independent Claim
83 words
A method of detecting breaking glass comprising: detecting by said transducer means structurally-transmitted vibrations of impact on glass for generating a first signal; gating a circuit in said transducer means responsive to said first signal to enable detection by said transducer means of airborne-transmitted sounds; detecting by said transducer means airborne-transmitted sounds emitted by breaking glass for generating a second signal; and combining said first and second signals in accordance with a time-dependent function to generate an alarm signal indicative of breaking glass.
Claim 3
Dependent Claim
22 words
The method according to claim 1 wherein said detecting of said structurally-transmitted vibrations and airborne-transmitted sounds is performed by a single transducer.
Claim 4
Dependent Claim
18 words
The method according to claim 1 wherein said first signal is of longer duration than said structurally-transmitted vibrations.
Claim 5
Dependent Claim
27 words
The method according to claim 3 wherein generation of said first signal is delayed until said structurally-transmitted vibrations have been detected for a first predetermined time interval.
Claim 6
Dependent Claim
27 words
The method according to claim 4 wherein generation of said second signal is delayed until said airborne-transmitted sound.., have been detected for a second predetermined time interval.
Claim 7
Dependent Claim
20 words
The method according to claim 5 wherein said first and said second predetermined time intervals are substantially equal in duration.
Claim 8
Dependent Claim
21 words
The method according to claim 6 wherein said first and second time intervals are in the range of substantially 50-100 milliseconds.
Claim 9
Dependent Claim
19 words
The method according to claim 1 wherein said gating by said first signal provides a time-dependent Boolean AND function.
Claim 10
Dependent Claim
25 words
The method according to claim 1 wherein said structurally-transmitted vibrations utilized to generate said first signal are limited to a bandpass of substantially 100-400 Hz.
Claim 11
Dependent Claim
25 words
The method according to claim 9 wherein said airborne-transmitted sounds utilized to generate said second signal are limited to a bandpass of substantially 6-7 KHz.
Claim 12
Dependent Claim
97 words
Apparatus for detecting breaking glass comprising: transducer means for detecting structurally=transmitted vibrations of impact on glass and airborne-transmitted sounds emitted by breaking glass and having an output signal; circuit means coupled to said transducer means for generating a first signal in response to said structurally-transmitted vibrations, said first signal gating a filter circuit for receiving said airborne-transmitted sounds and for combining in accordance with a time-dependent function information in said output signal indicative of said structurally-transmitted vibrations with information in said output signal indicative of said airborne-transmitted sounds for generating an alarm signal indicative of breaking glass.
Claim 13
Dependent Claim
97 words
Apparatus for detecting breaking glass comprising: transducer means for detecting structurally=transmitted vibrations of impact on glass and airborne-transmitted sounds emitted by breaking glass and having an output signal; circuit means coupled to said transducer means for generating a first signal in response to said structurally-transmitted vibrations, said first signal gating a filter circuit for receiving said airborne-transmitted sounds and for combining in accordance with a time-dependent function information in said output signal indicative of said structurally-transmitted vibrations with information in said output signal indicative of said airborne-transmitted sounds for generating an alarm signal indicative of breaking glass.
Claim 14
Dependent Claim
12 words
Apparatus according claim 11 wherein said transducer means comprises a single transducer.
Claim 15
Dependent Claim
11 words
Apparatus according to claim 12 wherein said transducer comprises a microphone.
Claim 16
Dependent Claim
12 words
Apparatus according to claim 12 wherein said transducer comprises a piezoelectric element.
Claim 17
Dependent Claim
18 words
The apparatus according to claim 12 wherein said first signal is of longer duration than said structurally-transmitted vibrations.
Claim 18
Dependent Claim
29 words
The apparatus according to claim 15 wherein said circuit means delays generation of said first signal until said structurally-transmitted vibrations have been detected for a first predetermined time interval.
Claim 19
Dependent Claim
19 words
Apparatus according to claim 16 wherein said filter circuit generates a second signal in response to said airborne-transmitted sounds.
Claim 20
Dependent Claim
29 words
The apparatus according to claim 17 wherein said filter circuit delays generation of said second signal until said airborne-transmitted sounds have been detected for a second predetermined time interval.
Claim 21
Dependent Claim
20 words
The apparatus according to claim 18 wherein said first and said second predetermined time intervals are substantially equal in duration.
Claim 22
Dependent Claim
20 words
The apparatus according to claim 19 wherein said first and second time intervals are in the range of substantially 50-100
Claim 23
Dependent Claim
25 words
The apparatus according to claim 11 wherein said structurally-transmitted vibrations utilized to generate said first signal are limited to a bandpass of substantially 100-400 Hz.
Claim 24
Dependent Claim
25 words
The apparatus according to claim 17 wherein said airborne-transmitted sounds utilized to generate said second signal are limited to a bandpass of substantially 6-7 KHz.
Claim 25
Dependent Claim
18 words
Apparatus according to claim 11 wherein said gating by said first signal provides a time-dependent Boolean AND function.
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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) | 1995-05-26 | 1995-11-25 | 1996-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-26 | 1999-11-25 | 2000-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-26 | 2003-11-25 | 2004-05-26 | $7700.00 | Window Closed / Lapsed |