US4576482A
Expired / Lapsed
US
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Electro-optical inspection
Assignee: LMI Technologies Inc
•
Filing: 1981-06-02
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Granted: 1986-03-18
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Expires: 2001-06-02
Abstract
Abstract A method and apparatus for inspecting workpieces for rapid and accurate determination of dimensions and the like. The equipment is electro-optical in nature and there is no contact between the inspecting elements and the workpiece under inspection. An electro-optical sensor is utilized which includes a light source for illuminating at least one edge of a workpiece, a lens for forming an image of the illuminated edge, and an array of photosensitive elements, such as photodiodes, capable of producing an electrical signal in response to light incident thereon. The light, including the edge image, is impinged upon the array and the electrical signals produced correspond to the portion of the edge, its shape, etc. The signals can be rapidly analyzed to provide a determination of a dimension such as length, squareness, curvature, and the like.
Inventors
- 👤 Timothy R. Pryor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:36
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/24; G01B11/2433; F; F01; F01L; F01L1/00; F01L1/02; F01L1/04; F01L1/047
Claims Analysis
Total Claims: 72
Claim 1
Independent Claim
175 words
Apparatus for determining a dimension of an object to an accuracy of at least ±0.0004 inches comprising: an electro-optical sensor unit for sensing the positon of a portion of an object, said sensor unit comprising: light source means for illuminating an edge of said portion of an object; lens means for forming an image of the illuminated edge of an object; a photosensitive array comprising a plurality of light sensitive elements capable of producing a signal in response to light incident thereon, said array being positioned to receive the image of an illuminated edge of an object; electronic means for magnifying the resolution provided by said photosensitive array to a fraction of an individual light sensitive element, said electronic means including means for producing a fractional distance signal having a value indicative of the fractional distance between adjacent light sensitive elements; and means for analyzing the signals from said light sensitive elements and said fractional distance signal to determine a dimension of said portion of said object to an accuracy of at least 0.0004 inches.
Claim 2
Dependent Claim
175 words
Apparatus for determining a dimension of an object to an accuracy of at least ±0.0004 inches comprising: an electro-optical sensor unit for sensing the positon of a portion of an object, said sensor unit comprising: light source means for illuminating an edge of said portion of an object; lens means for forming an image of the illuminated edge of an object; a photosensitive array comprising a plurality of light sensitive elements capable of producing a signal in response to light incident thereon, said array being positioned to receive the image of an illuminated edge of an object; electronic means for magnifying the resolution provided by said photosensitive array to a fraction of an individual light sensitive element, said electronic means including means for producing a fractional distance signal having a value indicative of the fractional distance between adjacent light sensitive elements; and means for analyzing the signals from said light sensitive elements and said fractional distance signal to determine a dimension of said portion of said object to an accuracy of at least 0.0004 inches.
Claim 3
Dependent Claim
17 words
Apparatus according to claim 1 for determining said dimension to an accuracy of at least ±0.0001 inches.
Claim 4
Dependent Claim
17 words
Apparatus according to claim 1 for determining said dimension to an accuracy of at least ±0.00005 inches.
Claim 5
Dependent Claim
21 words
Apparatus according to claim 1 wherein said object is a machined part and comprises a crankshaft, a valve, or a camshaft.
Claim 6
Dependent Claim
17 words
Apparatus according to claim 1 wherein said apparatus further comprises means for rotating a mounted elongate object.
Claim 7
Dependent Claim
65 words
Apparatus according to claim 5 wherein said light source means comprises means for strobing the light to effectively freeze the image of the edge of a rotating object on said photodiode array, said apparatus further comprising means for determining the angular position of a rotating object and means for actuating the strobe light pulse at an angular position determined by said angular position determining means.
Claim 8
Dependent Claim
15 words
Apparatus according to claim 6 wherein said light source means comprises a pulsed diode laser.
Claim 9
Dependent Claim
13 words
Apparatus according to claim 1 further comprising means for compensating for light fluctuations.
Claim 10
Dependent Claim
22 words
Apparatus according to claim 8 wherein said light compensation means comprises means for detecting the intensity of light incident on said array.
Claim 11
Dependent Claim
28 words
Apparatus according to claim 1 wherein said object comprises a camshaft and wherein said illuminated edge comprises an edge of a cam lobe or journal of said camshaft.
Claim 12
Dependent Claim
26 words
Apparatus according to claim 10 comprising means for monitoring the angular position of an illuminated cam lobe edge relative to a reference point on said camshaft.
Claim 13
Dependent Claim
33 words
Apparatus according to claim 11 wherein said dimension is cam lift and further means are provided to analyze the relationship between said dimension and said angular position so as to determine lobe contour.
Claim 14
Dependent Claim
16 words
Apparatus according to claim 10 wherein said dimension is base circle runout of a cam lobe.
Claim 15
Dependent Claim
30 words
Apparatus according to claim 10 further comprising a cylinder lens mounted adjacent said photodiode array to concentrate light from a range of positions along said edge onto said photodiode array.
Claim 16
Dependent Claim
65 words
Apparatus according to claim 10 wherein said sensor unit is positioned to sense an edge of a journal of a mounted camshaft and further comprising a further sensor unit for sensing a further edge of said journal of a mounted cam shaft, said further edge being diametrically opposite to the first mentioned journal edge for determining the diameter and center point location of said journal.
Claim 17
Dependent Claim
40 words
Apparatus according to claim 10 further comprising means for storing predetermined cam lobe lift data for a cam shaft type and wherein said analyzing means further comprises means for comparing the determined cam lobe lift data with said stored data.
Claim 18
Dependent Claim
39 words
Apparatus according to claim 16 wherein said storing means comprises means for storing predetermined cam lobe lift data for a plurality of cam shaft types and further comprising means for sensing the type of a cam shaft under inspection.
Claim 19
Dependent Claim
19 words
Apparatus according to claim 1 wherein said photodiode array comprises a linear array having at least 1000 discrete photodiodes.
Claim 20
Dependent Claim
20 words
Apparatus according to claim 1 wherein said electronic magnifying means comprises means for establishing a plurality of edge detection thresholds.
Claim 21
Dependent Claim
12 words
Apparatus according to claim 1 comprising a plurality of said sensor units.
Claim 22
Dependent Claim
21 words
Apparatus according to claim 1 further comprising means for moving said sensor unit relatively longitudinally of an object to predetermined locations.
Claim 23
Dependent Claim
33 words
Apparatus according to claim 21 further comprising a reference gage member located such that at one end of the relative movement of said sensor unit, said sensor unit senses the said reference gage.
Claim 24
Dependent Claim
16 words
Apparatus according to claim 1 wherein said light source means comprises a source of collimated light.
Claim 25
Dependent Claim
14 words
Apparatus according to claim 1 wherein said lens means comprises a telecentric lens system.
Claim 26
Dependent Claim
27 words
Apparatus according to claim 1 further comprising a lens stop positioned between said lens means and said photodiode array to block light reflected from an object's surface.
Claim 27
Dependent Claim
32 words
Apparatus according to claim 1 wherein said electro-optical sensor unit comprises a single lens and photodiode array located in a common housing, said housing being moveably mounted to accomodate different object sizes.
Claim 28
Dependent Claim
25 words
Apparatus according to claim 1 wherein two diametrically opposite edges of said object are both imaged by a single lens onto a single photodiode array.
Claim 29
Dependent Claim
13 words
Apparatus according to claim 27 wherein said array comprises at least 1000 elements.
Claim 30
Dependent Claim
27 words
Apparatus according to claim 1 wherein said light source is located below an object and wherein a window is provided between said light source and said object.
Claim 31
Dependent Claim
20 words
Apparatus according to claim 1 wherein said light source is oriented to direct the illuminating light horizontally across an object.
Claim 32
Dependent Claim
33 words
Apparatus according to claim 1 wherein said object comprises a crankshaft and wherein said sensor means is positioned to sense the position of a pin journal diameter or fillet contour of a crankshaft.
Claim 33
Dependent Claim
19 words
Apparatus according to claim 1 further comprising fiber optic means for transmitting said image to a remote photodiode array.
Claim 34
Dependent Claim
23 words
Apparatus according to claim 1 wherein said light source means comprises fiber optic means for transmitting light to said edge of said object.
Claim 35
Dependent Claim
16 words
Apparatus according to claim 1 further comprising means for mounting said object in a mounted position.
Claim 36
Dependent Claim
24 words
Apparatus according to claim 34 further comprising transfer means for moving an object from a loading position adjacent said apparatus into said mounted position.
Claim 37
Dependent Claim
14 words
Apparatus according to claim 34 wherein said mounting means comprises centers or vee supports.
Claim 38
Independent Claim
138 words
A method of determining a dimension of an object to an accuracy of at least ±0.0004 inches comprising: illuminating an edge of a portion of an object; forming an optical image of the illuminated edge of the object; detecting the image of the illuminated edge of the object on a photosensitive array of light sensitive elements capable of producing a signal in response to light incident thereon; electronically magnifying the resolution provided by the photosensitive array to a fraction of an individual light sensitive element by producing a fractional distance signal having a value indicative of the fractional distance between adjacent light sensitive elements; and analyzing the signals from said light sensitive elements and said fractional distance signal, so as to determine a dimension of said portion of said object to an accuracy of ± of 0.0004 inches.
Claim 39
Independent Claim
138 words
A method of determining a dimension of an object to an accuracy of at least ±0.0004 inches comprising: illuminating an edge of a portion of an object; forming an optical image of the illuminated edge of the object; detecting the image of the illuminated edge of the object on a photosensitive array of light sensitive elements capable of producing a signal in response to light incident thereon; electronically magnifying the resolution provided by the photosensitive array to a fraction of an individual light sensitive element by producing a fractional distance signal having a value indicative of the fractional distance between adjacent light sensitive elements; and analyzing the signals from said light sensitive elements and said fractional distance signal, so as to determine a dimension of said portion of said object to an accuracy of ± of 0.0004 inches.
Claim 40
Dependent Claim
18 words
A method according to claim 37 for determining said dimension to an accuracy of at least ±0.0001 inches.
Claim 41
Dependent Claim
18 words
A method according to claim 37 for determining said dimension to an accuracy of at least 0.00005 inches.
Claim 42
Dependent Claim
17 words
A method according to claim 37 wherein said object comprises a crankshaft, a valve, or a camshaft.
Claim 43
Dependent Claim
16 words
A method according to claim 37 wherein said method further comprises rotating a mounted elongate object.
Claim 44
Dependent Claim
57 words
A method according to claim 41 wherein said light source means comprises means for strobing the light to effectively freeze the image of a rotating object on said photosensitive array, said method further comprising the steps of determining the angular position of an object and actuating the strobe light at a determined angular position of said object.
Claim 45
Dependent Claim
16 words
A method according to claim 42 wherein said light source means comprises a pulsed diode laser.
Claim 46
Dependent Claim
12 words
A method according to claim 32 further comprising compensating for light fluctuations.
Claim 47
Dependent Claim
21 words
A method according to claim 44 wherein said light compensation step comprises detecting the intensity of light incident on said array.
Claim 48
Dependent Claim
29 words
A method according to claim 37 wherein said object comprises a camshaft and wherein said illuminated edge comprises an edge of a cam lobe or journaal of said camshaft.
Claim 49
Dependent Claim
37 words
A method according to claim 37 wherein said object comprises a camshaft, said method comprising the further step of monitoring the angular position of an illuminated cam lobe edge relative to a reference point on said camshaft.
Claim 50
Dependent Claim
32 words
A method according to claim 47 wherein said dimension is cam lift and further including the step of analyzing the relationship between said dimension and said angular position to determine lobe contour.
Claim 51
Dependent Claim
18 words
A method according to claim 48 wherein said dimension is a base circle runout of a cam lobe.
Claim 52
Dependent Claim
35 words
A method according to claim 37 further comprising concentrating light from a range of axial positions on an object onto said photosensitive array by means of a cylinder lens mounted adjacent to said photosensitive array.
Claim 53
Dependent Claim
21 words
A method according to claim 50 wherein said photosensitive array comprises a linear photodiode array having at least 1000 discrete photodiodes.
Claim 54
Dependent Claim
36 words
A method according to claim 50 wherein said lens and said photodiode array are located in a common housing and wherein said method includes the step of moving said housing to accomodate objects of different size.
Claim 55
Dependent Claim
19 words
A method according to claim 37 wherein said electronic magnifying step comprises establishing a plurality of edge detection thresholds.
Claim 56
Dependent Claim
56 words
A method according to claim 37 wherein said edge comprises an edge of a journal of camshaft and wherein said method further comprises the step of sensing a further edge of said journal, said further edge being diametrically opposite to the first mentioned journal edge for determining the diameter and center point location of said journal.
Claim 57
Dependent Claim
41 words
A method according to claim 37 wherein said object comprises a camshaft, said method further comprising the step of storing predetermined cam lobe lift data for a camshaft type and comparing the determined cam lobe lift data with said stored data.
Claim 58
Dependent Claim
38 words
A method according to claim 55 wherein said data storing step comprises storing predetermined cam lobe lift data for a plurality of camshaft types and further comprising the step of sensing the type of a camshaft under inspection.
Claim 59
Dependent Claim
16 words
A method according to claim 37 wherein said light source comprises a source of collimated light.
Claim 60
Dependent Claim
33 words
A method according to claim 37 wherein said object comprises a valve and wherein two diametrically opposite edges of said valve are both imaged by a single lens onto a single photosensitive array.
Claim 61
Dependent Claim
18 words
A method according to claim 37 wherein a window is provided between said light source and said object.
Claim 62
Dependent Claim
17 words
A method according to claim 37 further comprising the step of mounting said object on a support.
Claim 63
Dependent Claim
22 words
A method according to claim 60 further comprising the step of moving an object from a loading position into said mounted position.
Claim 64
Dependent Claim
38 words
A method according to claim 60 wherein said object comprises a valve and wherein said valve is transferred horizontally between a conveyor and said mounted position and wherein said light is projected upwardly from below a mounted valve.
Claim 65
Dependent Claim
12 words
A method according to claim 60 wherein said object comprises a crankshaft.
Claim 66
Dependent Claim
35 words
A method according to claim 63 wherein said step of mounting the crankshaft comprises automatically transferring the crankshaft between a position in which the crankshaft is located on a crankshaft conveyor and said mounted position.
Claim 67
Dependent Claim
23 words
A method according to claim 64 wherein said transferring step comprises lifting a crankshaft off a walking beam conveyor into said mounted position.
Claim 68
Dependent Claim
19 words
A method according to claim 63 wherein said edge comprises an edge of a pin journal of a crankshaft.
Claim 69
Dependent Claim
19 words
A method according to claim 63 wherein said edge comprises the edge of a fillet contour of a crankshaft.
Claim 70
Dependent Claim
14 words
A method according to claim 60 wherein said support comprises centers or vee supports.
Claim 71
Dependent Claim
20 words
A method according to claim 37 wherein said image is transmitted by fiber optic means to a remote photodiode array.
Claim 72
Dependent Claim
16 words
A method according to claim 37 wherein the incident light is transmitted by fiber optic means.
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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) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |