Patent US4564810A successfully refreshed from Google Patents.
US4564810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aluminum cladding thickness measurement probe and instrument having an automatic calibration and readout circuit coupled to a differential amplifier circuit
Assignee: Boeing Co
•
Filing: 1983-09-08
•
Granted: 1986-01-14
•
Expires: 2003-09-08
Abstract
Abstract A system for measuring the cladding thickness on aluminum sheets which includes a cylindrical probe holder with four evenly spaced contact points surrounding a low temperature coefficient torroidal ferrite core which provides a signal to an aluminum cladding thickness signal processing circuit comprising a crystal oscillator, low drift detector, and push button calibration instrument portion thereby enabling drift free repeatable measurements.
Inventors
- 👤 Glenn A. Geithman
- 👤 Albert W. Chau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:39
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
119 words
A cladding thickness measuring signal processing circuit comprising in combination: a power supply circuit coupled to a voltage regulator circuit; a low distortion, frequency stable 1.26 MHz oscillator circuit having amplitude feedback for providing amplitude stability; a power splitter circuit coupled between said voltage regulator circuit and said low distortion, frequency stable oscillator circuit; a bridge circuit including a test probe input terminal; a buffer and driver circuit coupled between said low distortion, frequency stable oscillator circuit and said bridge circuit; a differential amplifier circuit; a detector circuit having peak detectors with thermo-tracking, said detector circuit coupled between said differential amplifier circuit and said bridge circuit; and, an automatic calibration and readout circuit coupled to said differential amplifier circuit.
Claim 2
Dependent Claim
119 words
A cladding thickness measuring signal processing circuit comprising in combination: a power supply circuit coupled to a voltage regulator circuit; a low distortion, frequency stable 1.26 MHz oscillator circuit having amplitude feedback for providing amplitude stability; a power splitter circuit coupled between said voltage regulator circuit and said low distortion, frequency stable oscillator circuit; a bridge circuit including a test probe input terminal; a buffer and driver circuit coupled between said low distortion, frequency stable oscillator circuit and said bridge circuit; a differential amplifier circuit; a detector circuit having peak detectors with thermo-tracking, said detector circuit coupled between said differential amplifier circuit and said bridge circuit; and, an automatic calibration and readout circuit coupled to said differential amplifier circuit.
Claim 3
Dependent Claim
52 words
The invention according to claim 1 wherein said automatic calibration and readout circuit includes: a sample and hold circuit coupled to a further differential amplifier circuit; a readout meter; a scaling circuit coupled between said differential amplifier circuit and said readout meter; and, a voltage comparator circuit coupled to said scaling circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-13 | 1989-07-15 | 1990-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-13 | 1993-07-15 | 1994-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-13 | 1997-07-15 | 1998-01-14 | $7700.00 | Window Closed / Lapsed |