Patent US4820953A successfully refreshed from Google Patents.
US4820953A
Expired / Lapsed
US
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Rate of ascent monitor using piezoelectric transducer
Assignee: STITMA SCIENTIFIC Inc
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Filing: 1987-11-23
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Granted: 1989-04-11
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Expires: 2007-11-23
Abstract
Abstract A rate of ascent monitor for drivers uses a sound transducer with velocity characteristics, preferably a diaphragm type piezoelectric transducer, to sense rate of pressure change, and a threshold detector connected to the transducer to drive an indicator providing a warning of an excessive rate of ascent. A second threshold detector can be used to discriminate between descending and ascending motion. The device can be a compact wrist mounted unit.
Inventors
- 👤 Malcolm Saubolle
- 👤 Italo De Blasi
- 👤 Stanley Livshitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:52
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0644; B06B1/0662; B06B1/0666; G; G01; G01L; G01L9/00; G01L9/0041; G01L9/008; G01P; G01P3/00; G01P3/62
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
A submersible rate of ascent monitor for divers, comprising a body defining a chamber, a diaphragm of a piezoelectric sound transducer closing an opening in said body so as hermetically to seal the chamber from the surrounding water, a piezoelectric ceramic wafer of the sound transducer being bonded to the inside surface of the diaphragm, a low pass filter electrically connected to the transducer output to exclude therefrom signals due to sounds, water movements and impacts, a threshold detector circuit within the chamber and receiving an output of the low pass filter, said threshold detector having a first threshold corresponding to a rate of decrease of ambient pressure indicative of an excessive rate of ascent, and indicator means driven by the threshold detector circuit to indicate an excessive rate of descent.
Claim 2
Dependent Claim
131 words
A submersible rate of ascent monitor for divers, comprising a body defining a chamber, a diaphragm of a piezoelectric sound transducer closing an opening in said body so as hermetically to seal the chamber from the surrounding water, a piezoelectric ceramic wafer of the sound transducer being bonded to the inside surface of the diaphragm, a low pass filter electrically connected to the transducer output to exclude therefrom signals due to sounds, water movements and impacts, a threshold detector circuit within the chamber and receiving an output of the low pass filter, said threshold detector having a first threshold corresponding to a rate of decrease of ambient pressure indicative of an excessive rate of ascent, and indicator means driven by the threshold detector circuit to indicate an excessive rate of descent.
Claim 3
Dependent Claim
44 words
A monitor according to claim 1, wherein the threshold detector circuit has a second threshold corresponding to a very small or zero rate of pressure change, and further indicator means driven by said threshold detector to indicate whether a diver is ascending or descending.
Claim 4
Dependent Claim
18 words
A monitor according to claim 1, wherein the ceramic wafer is covered with a moisture resistant dielectric layer.
Claim 5
Dependent Claim
20 words
A monitor according to claim 1, including a wrist strap for securing the monitor to the wrist of a user.
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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) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |