US4820972A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wall thickness detector
Assignee: GLASS MACHINERY Inc A Corp OF
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Filing: 1987-07-02
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Granted: 1989-04-11
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Expires: 2007-07-02
Abstract
Abstract A capacitive probe for a wall thickness detector comprises a plurality of flexible capacitive elements and an elastomeric body supporting the flexible capacitive elements and biasing them against a dielectric body at an inspection site. A first metallic shield is supported between the elastomeric body and the capacitive elements and a second metallic shield is supported on the other side of the capacitive elements in close proximity thereto and has a window to expose the capacitive elements to the dielectric member.
Inventors
- 👤 Paul F. Scott
- 👤 Donald C. Button
- 👤 Charles B. Reeves
- 👤 Edward D. Howerter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:34
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/08; B; B07; B07C; B07C5/00; B07C5/04; B07C5/12; B07C5/122; B07C5/128; B07C5/34; B07C5/3404; B07C5/3408
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
194 words
A capacitive circuit laminate for a capacitive probe in a wall thickness detector, said capacitive circuit laminate comprising: a middle layer including three elongated, equally spaced flexible metallic capacitive elements, means for applying a non-zero voltage waveform to the central of said capacitive elements, and means for shorting said other two outer capacitance elements to ground so that a capacitance field will be generated which is confined to a region approximately bounded by parallel planes through said outer capacitance elements and normal to said middle layer, a rear layer including a thin metallic shield for shielding the rear surface of said middle layer, and a front layer including a thin metallic shield for shielding the front surface of said middle layer and having a window for exposing a selected length of said capacitive elements of said middle layer whereby an electromagnetic field may emanate from said central one of said capacitive elements, pass outwardly through said window into the vicinity of a dielectric member, and return back through said window to said outer capacitive elements, and means for driving the thin metallic shields of said rear and front layers with said non-zero voltage waveform.
Claim 2
Dependent Claim
194 words
A capacitive circuit laminate for a capacitive probe in a wall thickness detector, said capacitive circuit laminate comprising: a middle layer including three elongated, equally spaced flexible metallic capacitive elements, means for applying a non-zero voltage waveform to the central of said capacitive elements, and means for shorting said other two outer capacitance elements to ground so that a capacitance field will be generated which is confined to a region approximately bounded by parallel planes through said outer capacitance elements and normal to said middle layer, a rear layer including a thin metallic shield for shielding the rear surface of said middle layer, and a front layer including a thin metallic shield for shielding the front surface of said middle layer and having a window for exposing a selected length of said capacitive elements of said middle layer whereby an electromagnetic field may emanate from said central one of said capacitive elements, pass outwardly through said window into the vicinity of a dielectric member, and return back through said window to said outer capacitive elements, and means for driving the thin metallic shields of said rear and front layers with said non-zero voltage waveform.
Claim 3
Dependent Claim
64 words
A capacitive circuit laminate as set forth in claim 1 wherein said rear layer further includes an insulating layer to insulate said metallic shield of said rear layer from said metallic flexible elements of said middle layer, and said front layer includes a thin insulating layer to insulate said metallic shield of said front layer from said metallic flexible elements of said middle layer.
Claim 4
Dependent Claim
29 words
A capacitive laminate as set forth in claim 1 wherein said metallic shield of said rear layer shields the rear surface of at least one of said capacitive elements.
Claim 5
Dependent Claim
28 words
A capacitive circuit laminate as set forth in claim 3 wherein said metallic shield of said rear layer shields the rear surface of each of said capacitive elements.
Claim 6
Dependent Claim
35 words
A capacitive circuit laminate according to claim 1 wherein window means is defined in said rear layer beneath said window in said front layer to reduce radiation from the rear layer to said capacitance elements.
References Cited (Backward Citations)
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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 |