US4282520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric horn and a smoke detector containing same
Assignee: Individual
•
Filing: 1978-10-25
•
Granted: 1981-08-04
•
Expires: 1998-10-25
Abstract
Abstract An ionization smoke detector having two ionization chambers, one completely open to the ambient atmosphere and the other, a reference chamber, in communication with the atmosphere only through a breather tube having a defined length to diameter ratio. The detector employs a piezoelectric horn mounted on a cylindrical tube-like structure and attached to a printed circuit board containing one or more holes opposite the horn element so as to form a resonant chamber. The invention further contemplates a test switch which can be used to determine whether the battery is charged and the circuits are functioning.
Inventors
- 👤 John I. Shipp
- 👤 Charlie C. Rogers, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:56
CPC Classifications
G; G08; G08B; G08B3/00; G08B3/10; G08B17/00; G08B17/10; G08B17/11; G08B17/113; G08B29/00; G08B29/12; G08B29/14; G08B29/145; G08B29/18; G08B29/181
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
68 words
A smoke detector comprising two ionization chambers, a first ionization chamber essentially completely open to the ambient atmosphere and a second partially closed ionization chamber having at least one means for restricting the passage of smoke particles into the chamber while allowing rapid equilibration of atmospheric pressure and humidity, said means comprising a breather tube having a length to diameter ratio of from about 5:1 to about 1000:1.
Claim 2
Dependent Claim
68 words
A smoke detector comprising two ionization chambers, a first ionization chamber essentially completely open to the ambient atmosphere and a second partially closed ionization chamber having at least one means for restricting the passage of smoke particles into the chamber while allowing rapid equilibration of atmospheric pressure and humidity, said means comprising a breather tube having a length to diameter ratio of from about 5:1 to about 1000:1.
Claim 3
Dependent Claim
23 words
The smoke detector of claim 1, wherein the breather tube has a length to diameter ratio of from about 20:1 to about 300:1.
Claim 4
Dependent Claim
22 words
The smoke detector of claim 2, wherein the breather tube has a length of 1 inch and a diameter of 0.02 inches.
Claim 5
Dependent Claim
94 words
A smoke detector, comprising: a radioactive source enclosed in an ionization chamber wherein a voltage change is produced in response to the presence of smoke particles and wherein the voltage change activates a piezoelectric horn of the detector, the piezoelectric horn comprising a power source connected to an oscillator circuit and a tone transducer, wherein the tone transducer forms a surface of at least one resonant chamber having at least one air passage opposite the transducer and wherein the tone transducer is attached to the resonant chamber at the nodal circle of the transducer.
Claim 6
Dependent Claim
94 words
A smoke detector, comprising: a radioactive source enclosed in an ionization chamber wherein a voltage change is produced in response to the presence of smoke particles and wherein the voltage change activates a piezoelectric horn of the detector, the piezoelectric horn comprising a power source connected to an oscillator circuit and a tone transducer, wherein the tone transducer forms a surface of at least one resonant chamber having at least one air passage opposite the transducer and wherein the tone transducer is attached to the resonant chamber at the nodal circle of the transducer.
Claim 7
Dependent Claim
28 words
The smoke detector of claim 4, wherein the tone transducer comprises a piezo ceramic bonded to a metal disk and the ceramic is exterior to the resonant chamber.
Claim 8
Dependent Claim
28 words
The smoke detector of claim 6, wherein the tone transducer comprises a piezo ceramic bonded to a metal disk and the ceramic is interior to the resonant chamber.
Claim 9
Dependent Claim
14 words
The smoke detector of claim 6, further comprising a means for contacting the ceramic.
Claim 10
Dependent Claim
18 words
The smoke detector of claim 4, wherein the tone transducer comprises an oscillator ceramic and a feedback ceramic.
Claim 11
Dependent Claim
26 words
The smoke detector of claim 4, wherein the oscillator is a frequency stable oscillator and the transducer comprises one piezo ceramic bonded to a metal disk.
Claim 12
Dependent Claim
47 words
The smoke detector of claim 4, wherein the resonant chamber is formed by a cylindrical ring having the tone transducer contacting one end of the ring and a second surface having at least one aperture aligned opposite to the transducer contacting the other end of the ring.
Claim 13
Dependent Claim
19 words
The smoke detector of claim 10, wherein the end of the cylindrical ring contacting transducer has a knife edge.
Claim 14
Dependent Claim
15 words
The smoke detector of claim 10, wherein the second surface is a printed circuit board.
Claim 15
Dependent Claim
20 words
The smoke detector of claim 12, further comprising a means for securing the transducer and ring to the circuit board.
Claim 16
Dependent Claim
19 words
The smoke detector of claim 10, wherein the transducer and the second surface are hermetically sealed to the ring.
References Cited (Backward Citations)
US3879726A
Cited
DE2413162A1
Cited
US3953844A
Cited
US4081684A
Cited
US4035788A
Cited
US4096473A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |