US3703097A
Expired / Lapsed
US
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Method and system for measuring sheet flatness
Assignee: Kaiser Aluminum and Chemical Corp
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Filing: 1970-12-24
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Granted: 1972-11-21
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Expires: 1990-12-24
Abstract
Abstract A process for measuring sheet flatness comprising placing the sheet under sufficient longitudinal tension to remove substantially all internal compressive strains in the longitudinal direction and measuring the transverse profile of the sheet surface by suitable noncontacting proximity sensors and a system for such measurement.
Inventors
- 👤 Stanley A Kilpatrich
- 👤 Woodard A Niethammer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:17
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/28; G01B7/287; B; B21; B21B; B21B38/00; B21B38/02; B29; B29C; B29C48/00; B29C48/25; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92114; B29C2948/92171; B29C2948/92323; B29C2948/92447; B29C2948/92504; B29C2948/92523; B29C2948/92609; B29C2948/92666
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
150 words
A method for determining the flatness of sheet material comprising: A. Subjecting at least a pOrtion of said sheet material to longitudinal tension which is at least sufficient to remove substantially all internal compressive strains in the longitudinal direction but less than the yield strength of the material and to a substantially uniform force per unit area substantially normal to a surface of said portion, whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from a datum plane spacially disposed from a first surface of said portion to a plurality of pints on said first surface transverse to the longitudinal direction by noncontacting means without changing the double-curvature shape; and C. generating a plurality of signals which are related to the distance sensed in order to determine the transverse profile of the said surface.
Claim 2
Independent Claim
150 words
A method for determining the flatness of sheet material comprising: A. Subjecting at least a pOrtion of said sheet material to longitudinal tension which is at least sufficient to remove substantially all internal compressive strains in the longitudinal direction but less than the yield strength of the material and to a substantially uniform force per unit area substantially normal to a surface of said portion, whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from a datum plane spacially disposed from a first surface of said portion to a plurality of pints on said first surface transverse to the longitudinal direction by noncontacting means without changing the double-curvature shape; and C. generating a plurality of signals which are related to the distance sensed in order to determine the transverse profile of the said surface.
Claim 3
Independent Claim
150 words
A method for determining the flatness of sheet material comprising: A. Subjecting at least a pOrtion of said sheet material to longitudinal tension which is at least sufficient to remove substantially all internal compressive strains in the longitudinal direction but less than the yield strength of the material and to a substantially uniform force per unit area substantially normal to a surface of said portion, whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from a datum plane spacially disposed from a first surface of said portion to a plurality of pints on said first surface transverse to the longitudinal direction by noncontacting means without changing the double-curvature shape; and C. generating a plurality of signals which are related to the distance sensed in order to determine the transverse profile of the said surface.
Claim 4
Independent Claim
150 words
A method for determining the flatness of sheet material comprising: A. Subjecting at least a pOrtion of said sheet material to longitudinal tension which is at least sufficient to remove substantially all internal compressive strains in the longitudinal direction but less than the yield strength of the material and to a substantially uniform force per unit area substantially normal to a surface of said portion, whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from a datum plane spacially disposed from a first surface of said portion to a plurality of pints on said first surface transverse to the longitudinal direction by noncontacting means without changing the double-curvature shape; and C. generating a plurality of signals which are related to the distance sensed in order to determine the transverse profile of the said surface.
Claim 5
Dependent Claim
136 words
The method of claim 1 comprising the additional steps of: A. Subjecting said portion to approximately the same tension and the same uniform force per unit area in the opposite direction of said first uniform force per unit area substantially normal to a second surface of said portion as in step A of claim 1, whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from a datum plane spacially disposed from said second surface to a plurality of points on said second surface transverse to the longitudinal direction by noncontacting means without changing the double-curvature shape; and C. generating a second plurality of signals which are related to the distance sensed to determine a transverse profile of said second surface.
Claim 6
Dependent Claim
43 words
The method of claim 2 wherein the first plurality of signals is averaged with the second plurality of signals to produce a plurality of signals representing an average profile which indicates the rolled-in differential strain in said sheet material in an untensioned condition.
Claim 7
Dependent Claim
47 words
The method of claim 3 wherein the difference between one of the first and second plurality of signals and the plurality of signals representing the average profile is obtained to determine a deviation profile which indicates the permanent bend set caused by transverse and longitudinal bending strain.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein the tensioned portion of said sheet material is maintained in a horizontal position.
Claim 9
Dependent Claim
23 words
The method of claim 2 wherein the tensioned portion of said sheet material is maintained in a horizontal position during said second sensing.
Claim 10
Dependent Claim
14 words
The method of claim 1 wherein said profile is reproduced on a display device.
Claim 11
Dependent Claim
15 words
The method of claim 2 wherein said second profile is reproduced on a display device.
Claim 12
Dependent Claim
15 words
The method of claim 3 wherein said average profile is reproduced on a display device.
Claim 13
Dependent Claim
18 words
The method of claim 4 wherein the deviation from the average profile is reproduced on a display device.
Claim 14
Dependent Claim
20 words
The method of claim 1 wherein the tension is less than 50 percent of the yield strength of the material.
Claim 15
Dependent Claim
20 words
The method of claim 2 wherein the tension is less than 50 percent of the yield strength of the material.
Claim 16
Independent Claim
164 words
The method for determining the rolled-in differential strain in sheet material comprising: A. Subjecting at least a portion of said sheet material in a horizontal plane to longitudinal tension which is at least sufficient to remove substantially all internal strains in the longitudinal direction, but less than the yield strength of the material, whereby said portion assumes a double-curvature shape which is characteristic of internal strains of said portion in an untensioned condition; B. sensing the distance from the pass line of the tension applying means to at least three points on a first surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means without changing said double-curvature shape; C. generating a plurality of signals whiCh are related to the distances sensed in order to determine the transverse profile of said surface; and D. utilizing said signals in determining the rolled-in differential strain, epsilon 0, by computing means from the equation epsilon 0 ( gamma L2/16E) ((2/dc) - (1/da) -(1/db)).
Claim 17
Independent Claim
164 words
The method for determining the rolled-in differential strain in sheet material comprising: A. Subjecting at least a portion of said sheet material in a horizontal plane to longitudinal tension which is at least sufficient to remove substantially all internal strains in the longitudinal direction, but less than the yield strength of the material, whereby said portion assumes a double-curvature shape which is characteristic of internal strains of said portion in an untensioned condition; B. sensing the distance from the pass line of the tension applying means to at least three points on a first surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means without changing said double-curvature shape; C. generating a plurality of signals whiCh are related to the distances sensed in order to determine the transverse profile of said surface; and D. utilizing said signals in determining the rolled-in differential strain, epsilon 0, by computing means from the equation epsilon 0 ( gamma L2/16E) ((2/dc) - (1/da) -(1/db)).
Claim 18
Independent Claim
305 words
The method for determining the rolled-in differential strain in sheet material comprising: A. Subjecting at least a portion of said sheet material in a horizontal plane to longitudinal tension which is at least sufficient to remove substantially all internal strains in the longitudinal direction, but less than the yield strength of the material whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from the pass line of the tension applying means to at least three points on a first surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means without changing said double-curvature shape; C. generating a first plurality of signals which are related to the distances sensed in order to determine the transverse profile of said portion; D. inverting said portion of the sheet material; E. subjecting said portion to approximately the same tension as in step A above whereby said portion assumes a double-curvature shape which is characteristic of the internal strains in said portion in an untensioned condition; F. sensing the distance from the pass line of the tension applying means to at least three points on said surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means; G. generating a second plurality of signals which are related to the distances sensed in order to determine transverse profile of said portion; H. averaging the first and second plurality of signals to produce a plurality of signals representing an average profile which is characteristic of the rolled-in differential strains in said sheet in an untensioned condition; and I. utilizing said signals representing the average profile in determining the rolled-in differential strain, epsilon 0, by computing means from the equation epsilon 0 ( gamma L2/16E) ((2/dc) - (1/da) - (1/db)).
Claim 19
Independent Claim
305 words
The method for determining the rolled-in differential strain in sheet material comprising: A. Subjecting at least a portion of said sheet material in a horizontal plane to longitudinal tension which is at least sufficient to remove substantially all internal strains in the longitudinal direction, but less than the yield strength of the material whereby said portion assumes a double-curvature shape which is characteristic of the internal strains of said portion in an untensioned condition; B. sensing the distance from the pass line of the tension applying means to at least three points on a first surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means without changing said double-curvature shape; C. generating a first plurality of signals which are related to the distances sensed in order to determine the transverse profile of said portion; D. inverting said portion of the sheet material; E. subjecting said portion to approximately the same tension as in step A above whereby said portion assumes a double-curvature shape which is characteristic of the internal strains in said portion in an untensioned condition; F. sensing the distance from the pass line of the tension applying means to at least three points on said surface of said portion transverse to the longitudinal direction by noncontacting proximity sensing means; G. generating a second plurality of signals which are related to the distances sensed in order to determine transverse profile of said portion; H. averaging the first and second plurality of signals to produce a plurality of signals representing an average profile which is characteristic of the rolled-in differential strains in said sheet in an untensioned condition; and I. utilizing said signals representing the average profile in determining the rolled-in differential strain, epsilon 0, by computing means from the equation epsilon 0 ( gamma L2/16E) ((2/dc) - (1/da) - (1/db)).
Claim 20
Dependent Claim
185 words
In the process of measuring sheet flatness wherein the sheet material is placed in tension and the tension across the width of said sheet material transverse to longitudinal direction is sensed at a plurality of points by tension sensing means, the improvement comprising sensing the tension across the width of the sheet material at a plurality of points by tension sensing means adjacent one surface of said sheet material, generating a first plurality of signals which are related to tension measured to determine a first tension profile, sensing the tension across the width of the sheet material at a plurality of points by tension sensing means adjacent the other surface of said sheet material, generating a second plurality of signals which are related to the tension measured to determine a second tension profile, averaging the first and second plurality of signals to provide a plurality of signals representing an average tension profile which indicates the rolled-in differential strain in said sheet material in the untensioned condition, the tension and forces substantially normal to the surface in the first and second tension determinations being substantially equivalent.
Claim 21
Dependent Claim
185 words
In the process of measuring sheet flatness wherein the sheet material is placed in tension and the tension across the width of said sheet material transverse to longitudinal direction is sensed at a plurality of points by tension sensing means, the improvement comprising sensing the tension across the width of the sheet material at a plurality of points by tension sensing means adjacent one surface of said sheet material, generating a first plurality of signals which are related to tension measured to determine a first tension profile, sensing the tension across the width of the sheet material at a plurality of points by tension sensing means adjacent the other surface of said sheet material, generating a second plurality of signals which are related to the tension measured to determine a second tension profile, averaging the first and second plurality of signals to provide a plurality of signals representing an average tension profile which indicates the rolled-in differential strain in said sheet material in the untensioned condition, the tension and forces substantially normal to the surface in the first and second tension determinations being substantially equivalent.
Claim 22
Dependent Claim
50 words
The process of claim 15 wherein the difference between one of the first and second plurality of signals and the signals representing the average tension profile is obtained to determine a deviation from the average tension profile which indicates the permanent bend set caused by transverse and longitudinal bending strains.
Claim 23
Independent Claim
103 words
A system for determining sheet flatness comprising; A. means to apply sufficient tension to a sheet to remove substantially all internal compressive strains therein, whereby said sheet assumes a double-curvature shape which is characteristic of the internal strains of said sheet in an untensioned condition; B. a plurality of noncontacting proximity sensing means in a datum plane adjacent to and spacially disposed from a surface of said sheet in its tensioned state; and C. means associated with each of said proximity sensing means to generate a signal which is related to the distance from the datum plane to the surface of the sheet.
Claim 24
Independent Claim
103 words
A system for determining sheet flatness comprising; A. means to apply sufficient tension to a sheet to remove substantially all internal compressive strains therein, whereby said sheet assumes a double-curvature shape which is characteristic of the internal strains of said sheet in an untensioned condition; B. a plurality of noncontacting proximity sensing means in a datum plane adjacent to and spacially disposed from a surface of said sheet in its tensioned state; and C. means associated with each of said proximity sensing means to generate a signal which is related to the distance from the datum plane to the surface of the sheet.
Claim 25
Dependent Claim
84 words
The system of claim 17, including: A. A second means to apply sufficient tension to said sheet to remove substantially all internal compressive strains therein; B. a second plurality of noncontacting proximity sensing means in a second datum plane adjacent to and spacially disposed from the other surface of said sheet; and C. means associated with each of said second proximity sensing means to generate a second signal which is related to the second distance from the second datum plane to the other surface.
Claim 26
Dependent Claim
23 words
The system of claim 18, including means to average said first and second signals whereby an average profile of said sheet is developed.
Claim 27
Dependent Claim
20 words
The system of claim 17, including means to display said first signals as a first transverse profile of said sheet.
Claim 28
Dependent Claim
22 words
The system of claim 18, including means to display said second plurality of signals as a second transverse profile of said sheet.
Claim 29
Dependent Claim
34 words
The system of claim 19, including means to obtain a difference between one of the first or second plurality of signals and the signals representing the average profile, whereby a deviation profile is developed.
Claim 30
Dependent Claim
12 words
The system of claim 19, including means to display the average profile.
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) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |