US3857095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring the thickness of a coating on a substrate
Assignee: Vickers Ltd
•
Filing: 1972-07-25
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Granted: 1974-12-24
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Expires: 1992-07-25
Abstract
Abstract The thickness of a coating, such as an ink film, on a substrate, such as a printing surface, is determined by supporting a transducer on a cushion of gas at a constant distance from the surface of the coating of the coated substrate as the coated substrate is moved past the transducer. The transducer is of the type which has an electrical property which varies in dependence on the proximity of the transducer to a surface of electrically conductive material and the presence of the coating on the substrate causes a variation in the distance between the transducer and a surface of electrically conductive material (which may be the surface of the substrate) in accordance with the coating thickness. The resultant change in electrical property is determined and is a measure of the coating thickness. When applying coatings, the amount of coating material applied to a subsequent portion of the substrate may be regulated in dependence on the thickness of the coating on a preceding portion of the substrate so that the thickness of the coating on the subsequent portion of the substrate is equal to a desired thickness.
Inventors
- 👤 R Mitchie
- 👤 P Hyatt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:21
CPC Classifications
B; B41; B41F; B41F33/00; B41F33/0063; B41F31/00; G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
143 words
A method of determining the thickness of coating on the surface of a substrate, which method comprises: i. effecting relative movement between the coated substrate and a displacement transducer having an electrical property which varies in dependence on its proximity to electrically conductive material, ii. supporting the transducer by means of a cushion of a gas so that the transducer is spaced from the surface of the coating of the relatively moving substrate by a constant distance and is spaced from a surface of an electrically conductive material by a distance which varies in dependence on the thickness of the coating of the relatively moving coated substrate, and; iii. measuring the variation in said electrical property of the transducer as the distance separating the transducer and the surface of electrically conductive material varies to obtain a measure of the thickness of the coating.
Claim 2
Independent Claim
143 words
A method of determining the thickness of coating on the surface of a substrate, which method comprises: i. effecting relative movement between the coated substrate and a displacement transducer having an electrical property which varies in dependence on its proximity to electrically conductive material, ii. supporting the transducer by means of a cushion of a gas so that the transducer is spaced from the surface of the coating of the relatively moving substrate by a constant distance and is spaced from a surface of an electrically conductive material by a distance which varies in dependence on the thickness of the coating of the relatively moving coated substrate, and; iii. measuring the variation in said electrical property of the transducer as the distance separating the transducer and the surface of electrically conductive material varies to obtain a measure of the thickness of the coating.
Claim 3
Independent Claim
143 words
A method of determining the thickness of coating on the surface of a substrate, which method comprises: i. effecting relative movement between the coated substrate and a displacement transducer having an electrical property which varies in dependence on its proximity to electrically conductive material, ii. supporting the transducer by means of a cushion of a gas so that the transducer is spaced from the surface of the coating of the relatively moving substrate by a constant distance and is spaced from a surface of an electrically conductive material by a distance which varies in dependence on the thickness of the coating of the relatively moving coated substrate, and; iii. measuring the variation in said electrical property of the transducer as the distance separating the transducer and the surface of electrically conductive material varies to obtain a measure of the thickness of the coating.
Claim 4
Independent Claim
143 words
A method of determining the thickness of coating on the surface of a substrate, which method comprises: i. effecting relative movement between the coated substrate and a displacement transducer having an electrical property which varies in dependence on its proximity to electrically conductive material, ii. supporting the transducer by means of a cushion of a gas so that the transducer is spaced from the surface of the coating of the relatively moving substrate by a constant distance and is spaced from a surface of an electrically conductive material by a distance which varies in dependence on the thickness of the coating of the relatively moving coated substrate, and; iii. measuring the variation in said electrical property of the transducer as the distance separating the transducer and the surface of electrically conductive material varies to obtain a measure of the thickness of the coating.
Claim 5
Dependent Claim
26 words
A method according to claim 1, wherein the surface of the substrate is formed of electrically conductive material and constitutes said surface of electrically conductive material.
Claim 6
Dependent Claim
13 words
A method according to claim 2, wherein said coating is an ink film.
Claim 7
Dependent Claim
38 words
A method according to claim 1, wherein the surface of the substrate is formed of non-electrically conductive material and wherein said surface of electrically conductive material is constituted by a surface additional to the surface of the substrate.
Claim 8
Dependent Claim
20 words
A method according to claim 1, wherein the transducer is an inductive type transducer and said electrical property is inductance.
Claim 9
Dependent Claim
20 words
A method according to claim 1, wherein the transducer is a capacitance type transducer and said electrical property is capacitance
Claim 10
Dependent Claim
86 words
A device as claimed in claim 7, wherein said supporting member is in the form of a tube, said element is secured to a piston axially slidable within the tube, said tube includes an inlet for the introduction of gas into the tube and arranged so that the gas introduced thereby acts on the piston and displaces the same, together with the element, towards the substrate, and said piston is provided with a longitudinally extending bore to conduct gas to the discharge outlets from the inlet.
Claim 11
Dependent Claim
62 words
A device as claimed in claim 8, wherein said piston is axially slidable within another piston which is axially slidable with respect to the tube and wherein the gas introduced through the inlet also acts on said another piston to displace said another piston towards the substrate in opposition to a means provided to displace said another piston away from the substrate.
Claim 12
Dependent Claim
33 words
A device as claimed in claim 9, wherein said bore is provided with lateral air jets whereby air passing through the lateral air jets serves to centralise said piston within said another piston.
Claim 13
Dependent Claim
16 words
A device as claimed in claim 7, wherein the transducer iS an inductive type of transducer.
Claim 14
Dependent Claim
16 words
A device as claimed in claim 7, wherein the transducer is a capacitance type of transducer.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |