US3809987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic centering of objects in non-destructive test apparatus
Assignee: MAGNETIC ANALYSIS CORP US
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Filing: 1973-04-06
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Granted: 1974-05-07
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Expires: 1993-04-06
Abstract
Abstract Pairs of light sources and light responsive strips sense horizontal (H) and vertical (V) displacements of a cylindrical object from the axis of the test head in a non-destructive test apparatus prior to entering the test head. An object occludes light from the central portion of each strip and signals from the ends of each strip are amplified, detected and differentially combined to form respective servo control signals. The light sources in H and V channels are pulsated at frequencies different from each other and from the power mains, and the H and V channels are tuned thereto. The relative values of the signals in the H and V channels are initially adjusted to produce null servo control signals when an object is properly centered in the test head, and thereafter a servo system moves the position sensing and test heads to maintain centering. Signals from the individual channels are utilized to detect the ends of an object. A front end signal starts the servo control and, after a delay, starts the testing. A rear end signal discontinues servo control until the object has passed through the test head and then recenters the head for the next object.
Inventors
- 👤 P Suhr
- 👤 E Spierer
- 👤 G Mhatre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:32
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D3/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
317 words
In test apparatus for the non-destructive testing of generally cylindrical objects including test sensing means having a desired axis for travel of said objects therethrough and means for feeding objects therethrough, centering apparatus for maintaining a said object centered in said test sensing means which comprises a. position sensing means including pairs of light source and light responsive means positioned near and ahead of said test sensing means and angularly oriented about the path of travel of a said object to sense lateral displacements thereof in mutually perpendicular directions, b. mounting means for moving said posiTion and test sensing means relative to said object in said mutually perpendicular directions, c. each light source and respective light responsive means being positioned on opposite sides of said path of travel and having dimensions transverse of the path of travel such that said object occludes light from the central portion of the light responsive means and leaves areas thereof exposed to light on each side of the occluded area, d. means for pulsating said pair of light source means at respectively different frequencies, e. means for producing from each light responsive means a pair of signals varying with the light falling on respective sides of the occluded area thereof, f. respective means tuned to the frequency of said pair of signals from each light responsive means for amplifying and detecting said signals, g. means for differentially combining the pair of detected signals corresponding to each light responsive means to form respective servo control signals, h. null adjusting means for initially adjusting the relative values of the detected signals of each of said pairs to produce respective null servo control signals when an object is centered in said test sensing means, i. and a servo system responsive to said servo control signals for driving said mounting means to maintain an object centered in said test sensing means as it passes therethrough.
Claim 2
Dependent Claim
317 words
In test apparatus for the non-destructive testing of generally cylindrical objects including test sensing means having a desired axis for travel of said objects therethrough and means for feeding objects therethrough, centering apparatus for maintaining a said object centered in said test sensing means which comprises a. position sensing means including pairs of light source and light responsive means positioned near and ahead of said test sensing means and angularly oriented about the path of travel of a said object to sense lateral displacements thereof in mutually perpendicular directions, b. mounting means for moving said posiTion and test sensing means relative to said object in said mutually perpendicular directions, c. each light source and respective light responsive means being positioned on opposite sides of said path of travel and having dimensions transverse of the path of travel such that said object occludes light from the central portion of the light responsive means and leaves areas thereof exposed to light on each side of the occluded area, d. means for pulsating said pair of light source means at respectively different frequencies, e. means for producing from each light responsive means a pair of signals varying with the light falling on respective sides of the occluded area thereof, f. respective means tuned to the frequency of said pair of signals from each light responsive means for amplifying and detecting said signals, g. means for differentially combining the pair of detected signals corresponding to each light responsive means to form respective servo control signals, h. null adjusting means for initially adjusting the relative values of the detected signals of each of said pairs to produce respective null servo control signals when an object is centered in said test sensing means, i. and a servo system responsive to said servo control signals for driving said mounting means to maintain an object centered in said test sensing means as it passes therethrough.
Claim 3
Dependent Claim
22 words
Apparatus according to claim 1 in which said frequencies are substantially different from the power mains frequency and the second harmonic thereof.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 1 in which said null adjusting means adjusts the relative values of the signals from each of said light responsive means.
Claim 5
Dependent Claim
76 words
Apparatus according to claim 1 including a. means for initially disconnecting said servo control signals from said servo system, b. means for manually controlling said servo system to center an object in said test sensing means in said mutually perpendicular directions, respectively, c. means for indicating the values of said disconnected servo control signals during initial adjustment of said null adjusting means, d. and means for thereafter supplying said servo control signals to said servo system.
Claim 6
Dependent Claim
84 words
Apparatus according to claim 1 in which said test apparatus includes set-up means for initially indicating substantial centering of an object in said test sensing means, said centering apparatus including means for initially removing said servo control signals from said servo system, means for manually controlling said servo system until said set-up means indicates substantial centering, means for rendering said null adjusting means effective while said set-up means indicates substantial centering, and means for thereafter applying said servo control signals to said servo system.
Claim 7
Dependent Claim
53 words
Apparatus according to claim 1 including end detecting means responsive to at least one signal corresponding to the light falling on one side of the occluded area of at least one of said light responsive means for producing respective front and rear end signals indicating the entry and passage thereby of an object.
Claim 8
Dependent Claim
27 words
Apparatus according to claim 6 including delay means responsive to the initiation of a said front end signal for producing a start-test signal for said test apparatus.
Claim 9
Dependent Claim
129 words
Apparatus according to claim 6 including a. means for producing initial signals for said servo system corresponding to the centering of an object in said test sensing means in said mutually perpendicular directions, respectively, b. means responsive to the initiation of a said rear end signal for disabling control of said servo system by said servo control signals and stopping movement of said mounting means, c. means responsive to a said rear end signal for applying said initial signals to said servo system after a predetermined time delay and drive said mounting means to the initial centered position thereof, d. and means responsive to a succeeding front end signal for dIsabling control of said servo system by said initial signals and enabling control thereof by said servo control signals.
Claim 10
Dependent Claim
58 words
Apparatus according to claim 6 including means for averaging the magnitudes of a plurality of individual signals of said pairs of signals to produce a resultant signal whose magnitude is intermediate the maximum and minimum values of the individual signals, said resultant signal being applied to said end detecting means to produce said front and rear end signals.
Claim 11
Dependent Claim
175 words
Apparatus according to claim 9 including a. means for initially disconnecting said servo control signals from said servo system, b. means for producing initial signals for said servo system corresponding to the centering of an object in said test sensing means in said mutually perpendicular directions, respectively, c. means for indicating the values of said disconnected servo control signals during initial adjustment of said null adjusting means, d. means for thereafter supplying said servo control signals to said servo system, e. means responsive to the initiation of a said rear end signal for disabling control of said servo system by said servo control signals and stopping movement of said mounting means, f. means responsive to a said rear end signal for applying said initial signals to said servo system after a predetermined time delay and drive said mounting means to the initial centered position thereof, g. and means responsive to a succeeding front end signal for disabling control of said servo system by said initial signals and enabling control thereof by said servo control signals.
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) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |