US3764899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring variations in thickness of elongated samples of thin plastic film
Assignee: Modern Controls Inc
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Filing: 1972-02-14
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Granted: 1973-10-09
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Expires: 1992-02-14
Abstract
Abstract Capacitive type thickness measurement apparatus capable of measuring minute variations in the thickness of thin plastic films. A plastic film is passed through a suitably characterized electrode assembly which is of generally small surface area. The electrode is connected to control the changes in frequency of an oscillator. The output of the oscillator is suitably converted to provide a train of standardized, or constant energy pulses, from which an energy content determination is made to provide a recordable indication of the thickness of the plastic material.
Inventors
- 👤 P Peterson
- 👤 D Thon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:59
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/08; G01B7/087
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
179 words
The method of determining variations in lateral and longitudinal thickness of a plastic film sample, comprising the steps of; a. selecting a longitudinally elongated sample of plastic film material, the variations in thickness of which are to be recorded; b. providing a pair of adjustable electrodes having a very large length to width ratio and a width of less than 0.032 inches; c. adjustably mounting one end of each of said electrodes on a common base therefor; d. adjusting the gap between the electrodes to substantially the thickness of said sample; e. connecting the electrodes to a nominally high frequency oscillator means so as to affect the frequency thereof in accordance with variations in dielectric constant therebetween; f. providing a second adjustable oscillator means; g. adjusting the frequency of the second oscillator means to the same frequency as that of the first oscillator means, including said pair of electrodes; h. moving said strip longitudinally through the gap between said electrodes without any tension thereon; and i. serially recording any differences in frequency between said first and second oscillator means.
Claim 2
Independent Claim
179 words
The method of determining variations in lateral and longitudinal thickness of a plastic film sample, comprising the steps of; a. selecting a longitudinally elongated sample of plastic film material, the variations in thickness of which are to be recorded; b. providing a pair of adjustable electrodes having a very large length to width ratio and a width of less than 0.032 inches; c. adjustably mounting one end of each of said electrodes on a common base therefor; d. adjusting the gap between the electrodes to substantially the thickness of said sample; e. connecting the electrodes to a nominally high frequency oscillator means so as to affect the frequency thereof in accordance with variations in dielectric constant therebetween; f. providing a second adjustable oscillator means; g. adjusting the frequency of the second oscillator means to the same frequency as that of the first oscillator means, including said pair of electrodes; h. moving said strip longitudinally through the gap between said electrodes without any tension thereon; and i. serially recording any differences in frequency between said first and second oscillator means.
Claim 3
Dependent Claim
167 words
Apparatus for measuring minute variations in the thickness of a sample of thin plastic film comprising in combination; a. a substantially vertical base member; b. a first horizontally extending electrode member stationarily disposed on said base member; c. a second horizontally extending electrode member adjustably vertically disposed on said base member parallel to and adjacent to said first electrode to define a variable generally horizontally disposed gap, having a very large length to width ratio and a width of less than 0.032 inches therebetween; d. a first source of high frequency oscillatory signal, including a frequency determining means having a pair of input terminals therefor; e. a second source of high frequency oscillatory signal of predetermined constant frequency; f. means connecting one of said input terminals on the first source of signal to said first electrode and the other of said input terminals to said second electrode; and g. means for determining the variation in the difference in frequency of said first and second sources of signal.
Claim 4
Dependent Claim
167 words
Apparatus for measuring minute variations in the thickness of a sample of thin plastic film comprising in combination; a. a substantially vertical base member; b. a first horizontally extending electrode member stationarily disposed on said base member; c. a second horizontally extending electrode member adjustably vertically disposed on said base member parallel to and adjacent to said first electrode to define a variable generally horizontally disposed gap, having a very large length to width ratio and a width of less than 0.032 inches therebetween; d. a first source of high frequency oscillatory signal, including a frequency determining means having a pair of input terminals therefor; e. a second source of high frequency oscillatory signal of predetermined constant frequency; f. means connecting one of said input terminals on the first source of signal to said first electrode and the other of said input terminals to said second electrode; and g. means for determining the variation in the difference in frequency of said first and second sources of signal.
Claim 5
Dependent Claim
16 words
The apparatus of claim 2 in which one of the electrodes has a circular cross section.
Claim 6
Dependent Claim
30 words
The apparaTus of claim 2 in which the first and second electrodes are configured to substantially define a capacitance element including an elongated linear member and an elongated planar member.
Claim 7
Dependent Claim
19 words
The apparatus of claim 2 in which one of the electrodes is configured to define a longitudinally extending line.
References Cited (Backward Citations)
US2399582A
Cited
US2562575A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |