Patent US3749496A successfully refreshed from Google Patents.
US3749496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic quality control surface inspection system for determining the character of a surface by measuring the shape and intensity of a modulated beam
Assignee: Bendix Corp
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Filing: 1971-07-16
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Granted: 1973-07-31
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Expires: 1991-07-16
Abstract
Abstract An apparatus that automatically inspects the inside surface of a cylindrical workpice, such as a brake cylinder, by reflecting a beam of laser light from that surface. The intensity of the reflected beam is measured to detect the presence and severity of any surface flaws. The shape of the beam is measured to determine the smoothness of the cylinder surface. A computer compares the measured intensities and shapes of the reflected beam with predetermined intensity and shape values to determine the quality of the workpiece surface.
Inventors
- 👤 E Hietanen
- 👤 R Valek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:50
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/954; G01N21/17; G01N21/55
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
199 words
A system for inspecting the inside surface of a hollow cylindrical workpiece comprising: beam directing means including mirror means sufficiently small to fit inside the cylindrical workpiece and direct a beam of wave energy to strike and be modulated by the inside surface of said workpiece, and motive means for providing a relative rotation between said mirror means and said cylindrical workpiece to scan said beam around the inside surface of said cylinder and a relative longitudinal displacement between said mirror means and said cylindrical workpiece to scan said beam along the length of said cylindrical workpiece; surface smoothness determining means for measuring the crosssectional shape of said modulated beam to determine the smoothness of said surface, said smoothness determining means including detecting means for receiving the modulated beam, chopper means for controlling the transmission of said modulated beam to said detecting means, said chopper means progressively increasing and decreasing the field of view of said detecting means, and means for measuring the time rate of change in the intensity of said modulated wave energy striking said detecting means; and flaw detecting means for measuring the intensity of said modulated beam to determine whether said surface contains a flaw.
Claim 2
Independent Claim
199 words
A system for inspecting the inside surface of a hollow cylindrical workpiece comprising: beam directing means including mirror means sufficiently small to fit inside the cylindrical workpiece and direct a beam of wave energy to strike and be modulated by the inside surface of said workpiece, and motive means for providing a relative rotation between said mirror means and said cylindrical workpiece to scan said beam around the inside surface of said cylinder and a relative longitudinal displacement between said mirror means and said cylindrical workpiece to scan said beam along the length of said cylindrical workpiece; surface smoothness determining means for measuring the crosssectional shape of said modulated beam to determine the smoothness of said surface, said smoothness determining means including detecting means for receiving the modulated beam, chopper means for controlling the transmission of said modulated beam to said detecting means, said chopper means progressively increasing and decreasing the field of view of said detecting means, and means for measuring the time rate of change in the intensity of said modulated wave energy striking said detecting means; and flaw detecting means for measuring the intensity of said modulated beam to determine whether said surface contains a flaw.
Claim 3
Dependent Claim
80 words
The system of claim 1 in which said flaw detecting means comprise: low pass filter means for providing an output signal representing the average intensity of said modulated beam; high pass filter means for providing an output signal representing the instantaneous change of said modulated beam intensity; and comparator means for comparing the output signals from the two filter means and providing an output signal indicating the presence of a flaw in response to a difference between the compared signals.
Claim 4
Dependent Claim
115 words
The system of claim 1 in which: said flaw detecting means includes means for providing a first output signal indicating the presence of an intensity variation, and a second output signal indicating the value of the intensity of said modulated beam; the system includes computer means for generating command signals for said motive means; and said computer means also include control means responsive to said first and second output signals for interrupting the generation of command signals upon receipt of said first output signal from said flaw detecting means indicating the presence of a variation and initiating a determination of the value of said second signal to thereby determine the severity of a detected flaw.
Claim 5
Dependent Claim
106 words
The system of claim 1 in which: said motive means also provides said relative rotation to said chopper means; and said chopper means is shaped to prevent said detecting means from receiving said modulated beam from positions displaced from two longitudinal lines along the inside surface of said cylindrical workpiece and separated by a diameter of said cylindrical workpiece, said chopper means thereby preventing said detecting means from receiving said modulated beams from positions having different directions of curvature that alter the shape of said modulated beam in different manners and thereby provide an erroneous indication of a change in the smoothness of said workpiece surface.
Claim 6
Dependent Claim
31 words
The system of claim 4 in which said chopper means include two diametrically opposed notches for transmitting said modulated beam to said detecting means from along both of said longitudinal lines.
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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |