US3754146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for detecting streaks in coated layers on a web
Assignee: EIDP Inc
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Filing: 1972-03-27
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Granted: 1973-08-21
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Expires: 1992-03-27
Abstract
Abstract A detecting head and light source are synchronously traversed on opposite sides of a continuous moving web. Photoelectric detector elements are recessed in rectangular channels disposed symmetrically about rectangular coordinate axes, the principal axis of the rectangular channels is in the direction of web travel, and centered on the detecting head opposite the center of the synchronous traversing light source. A streak defect in a coated layer on the web interferes with the transmitted light to the detecting elements resulting in an electrical characteristic signal across the detecting elements. The characteristic signal is amplified, digitized and electronically processed for verification of the presence of a streak defect. The verified signal can be used to activate an alarm, halt the coating of the web or can be recorded and used for the design of subsequent slitting operations on the web.
Inventors
- 👤 A Chow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:52
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/892; G01N21/8921
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
108 words
An apparatus for detecting irregularities in a web of material comprising: 1. a light source disposed on one side of said web, 2. a detecting head having at least two symmetrically offset channels and photoelectric detecting elements recessed therein, said channels substantially collimating the light transmitted through and normal to said web from said light source and sequentially screening any variation in transmitted light incident on one photodetecting element from another photodetecting element, 3. a traversing mechanism for moving said detecting head across the width of said web, and 4. means for sequentially sensing the amplitude and polarity of the electrical signal produced by said photoelectric detecting elements.
Claim 2
Independent Claim
108 words
An apparatus for detecting irregularities in a web of material comprising: 1. a light source disposed on one side of said web, 2. a detecting head having at least two symmetrically offset channels and photoelectric detecting elements recessed therein, said channels substantially collimating the light transmitted through and normal to said web from said light source and sequentially screening any variation in transmitted light incident on one photodetecting element from another photodetecting element, 3. a traversing mechanism for moving said detecting head across the width of said web, and 4. means for sequentially sensing the amplitude and polarity of the electrical signal produced by said photoelectric detecting elements.
Claim 3
Dependent Claim
22 words
The apparatus of claim 1 wherein said light source is moved synchronously with said detecting means across the width of said web.
Claim 4
Dependent Claim
50 words
a detecting head having at least two symmetrically offset channels and photoelectric detecting elements recessed therein, said channels substantially collimating the light transmitted through and normal to said web from said light source and sequentially screening any variation in transmitted light incident on one photodetecting element from another photodetecting element,
Claim 5
Dependent Claim
50 words
a detecting head having at least two symmetrically offset channels and photoelectric detecting elements recessed therein, said channels substantially collimating the light transmitted through and normal to said web from said light source and sequentially screening any variation in transmitted light incident on one photodetecting element from another photodetecting element,
Claim 6
Dependent Claim
49 words
The apparatus of claim 1 wherein said symmetrically offset channels are rectangular, the distance between centers of said channels is substantially equal to the width of said channels, and the depth to which said detecting elements are recessed in said channels is at least 16 times the channel width.
Claim 7
Dependent Claim
15 words
a traversing mechanism for moving said detecting head across the width of said web, and
Claim 8
Dependent Claim
15 words
a traversing mechanism for moving said detecting head across the width of said web, and
Claim 9
Dependent Claim
18 words
means for sequentially sensing the amplitude and polarity of the electrical signal produced by said photoelectric detecting elements.
Claim 10
Dependent Claim
18 words
means for sequentially sensing the amplitude and polarity of the electrical signal produced by said photoelectric detecting elements.
Claim 11
Dependent Claim
33 words
The apparatus of claim 1 wherein said means for sensing comprises means for converting the electrical signal produced by said photoelectric detecting elements into recordable form, and means for recording the converted signal.
Claim 12
Dependent Claim
51 words
The apparatus of claim 4 wherein said means for sensing comprises a band pass amplifier including a differentiating network for differentiating and amplifying the signal from said detecting elements, and means for converting the amplified signal to a digital logic level signal, and means for recording said digital logic level signal.
Claim 13
Dependent Claim
24 words
An apparatus as recited in claim 1 wherein said detecting elements are recessed in said channels to a depth of at least 1/2 inch.
Claim 14
Independent Claim
78 words
A method of detecting irregularities in a web of material comprising: a. transmitting light from a light source through said web to a detecting head having at least two symmetrically offset channels with photoelectric detecting elements recessed therein, said photoelectric detecting elements being adapted to produce sequential electrical pulses of opposite polarity when traversed by a web irregularity, and b. sensing the time sequence and amplitude of said electrical pulses to identify the existence of a web irregularity.
Claim 15
Independent Claim
78 words
A method of detecting irregularities in a web of material comprising: a. transmitting light from a light source through said web to a detecting head having at least two symmetrically offset channels with photoelectric detecting elements recessed therein, said photoelectric detecting elements being adapted to produce sequential electrical pulses of opposite polarity when traversed by a web irregularity, and b. sensing the time sequence and amplitude of said electrical pulses to identify the existence of a web irregularity.
Claim 16
Dependent Claim
35 words
A method as recited in claim 7 wherein said electrical signal is substantially sinusoidal and said sequential pulses are of alternate polarity, and said signal is differentiated to enhance the characteristics representative of said irregularity.
Claim 17
Dependent Claim
52 words
A method as recited in claim 7 wherein sensing includes converting said electrical signal to digital logic level signal pulses, generating logic level gating pulses from said signal pulses, gating said signal pulses with said gating pulses to verify the time sequence of said sequential pulses to produce a verified defect signal.
Claim 18
Dependent Claim
26 words
The process as recited in claim 9 including the additional step of recording the verified defect signals and their lateral and longitudinal location on the web.
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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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |