US4804945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Door alarm with infrared and capacitive sensors
Assignee: Individual
•
Filing: 1987-10-29
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Granted: 1989-02-14
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Expires: 2007-10-29
Abstract
Abstract An alarm system for providing separate discrete signals corresponding with the approach of an individual to a door and the touching of the door knob by the individual utilizes a combination of infrared sensors and a capacitive discharge sensor. The infrared sensors are mounted on a circular ring on the face of the door knob. The sensors are angled in different directions to detect individuals approaching from various directions. The door knob is composed of a metallic material and acts as an antenna of a capacitive discharge proximity sensor. The door knob is insulated by a sleeve from the rest of the door and latch structure. Approach of an individual is detected by the infrared sensors which activates a first alarm signal. When the individual reaches for and touches the door knob, a second different alarm is activated.
Inventors
- 👤 Terrance Millet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:56
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/06; G08B13/18; G08B13/189; G08B13/19; G08B13/22; G08B13/26
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
183 words
A door alarm for providing two separate discrete signals indicating approach of an individual to a door and touching of the door knob by the individual, comprising: a metallic door knob on said door; a shaft connected to said door knob and a latch mechanism on said door; insulating means for electrically insulating said door knob and said shaft from said door and said latch mechanism; a key lock cylinder extending through a front face of said door knob; a circular mounting ring on said front face of said door knob surrounding said key lock cylinder; four infrared sensors spaced circumferentially at ninety degree intervals around said mounting ring; first control means connected to said infrared sensors; audible alarm means activated by said control means in response to approach of an individual to said door to provide a first signal; a capacitive discharge sensor connected to said metallic door knob; second control means connected to said capacitive discharge sensor; and means connected to said second control means for providing a second signal in response to touching of said door knob by an individual.
Claim 2
Dependent Claim
183 words
A door alarm for providing two separate discrete signals indicating approach of an individual to a door and touching of the door knob by the individual, comprising: a metallic door knob on said door; a shaft connected to said door knob and a latch mechanism on said door; insulating means for electrically insulating said door knob and said shaft from said door and said latch mechanism; a key lock cylinder extending through a front face of said door knob; a circular mounting ring on said front face of said door knob surrounding said key lock cylinder; four infrared sensors spaced circumferentially at ninety degree intervals around said mounting ring; first control means connected to said infrared sensors; audible alarm means activated by said control means in response to approach of an individual to said door to provide a first signal; a capacitive discharge sensor connected to said metallic door knob; second control means connected to said capacitive discharge sensor; and means connected to said second control means for providing a second signal in response to touching of said door knob by an individual.
Claim 3
Dependent Claim
42 words
A door alarm, comprising: door knob means; infrared sensor means on said door knob means for detecting approach of an individual remote from said door knob; and alarm means connected to said infrared sensor means activated by said approach of an individual.
Claim 4
Dependent Claim
42 words
A door alarm, comprising: door knob means; infrared sensor means on said door knob means for detecting approach of an individual remote from said door knob; and alarm means connected to said infrared sensor means activated by said approach of an individual.
Claim 5
Dependent Claim
54 words
A door alarm, comprising: door knob means; sensor means on said door knob means for detecting approach of an individual remote from said door knob; said sensor means comprising at least one infrared sensor and a capacitive discharge sensor; and alarm means connected to said sensor means activated by said approach of an individual.
Claim 6
Dependent Claim
54 words
A door alarm, comprising: door knob means; sensor means on said door knob means for detecting approach of an individual remote from said door knob; said sensor means comprising at least one infrared sensor and a capacitive discharge sensor; and alarm means connected to said sensor means activated by said approach of an individual.
Claim 7
Dependent Claim
32 words
The door alarm of claim 3, further comprising a circular mounting ring on a front face of said door knob means; and a plurality of infrared sensors circumferentially spaced around said ring.
Claim 8
Dependent Claim
26 words
The door alarm of claim 4, wherein said plurality of infrared sensors are each angled in a different direction to detect individuals approaching from various directions.
Claim 9
Dependent Claim
26 words
The door alarm of claim 3, wherein said door knob means is formed from a metallic material and is an antenna of said capacitive discharge sensor.
Claim 10
Dependent Claim
33 words
The door alarm of claim 6, wherein said door knob means includes a shaft; and insulating means on said shaft for electrically insulating said door knob means and said shaft from a door.
References Cited (Backward Citations)
US3785230A
Cited
US4325058A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |