US 5,012,116 AGranted

System for inspecting bearing balls for defects

OwnerJohn P. Russellinventor

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Abstract

By deriving the image formed by light specularly-reflected from substantially all of the convex (mirror-like) spherical surface of a bearing ball under test that is being illuminated with diffuse light, any defect in the bearing ball under test reveals itself as a light-contrast pattern in the otherwise substantially uniform diffuse background of the image.

Claims26

Dependent claims

In a system for inspecting a bearing ball for the presence of a defect in the normally specularly-reflecting convex surface thereof;

wherein said system comprises first means including a diffuser having an aperture therein for illuminating at least a portion of said convex surface with diffuse light, thereby to reflect a light-contrast pattern of a defect, if present, with respect to a diffuse-light background reflected from said normally specularly-reflecting portion of said surface, and second means, including light-imaging means positioned to be responsive to only that light reflected from said portion of said surface which has passed through said aperture, for detecting the presence of a defect-indicating light-contrast pattern;
the improvement wherein:
(a) said light-imaging means includes at least one one-dimensional imager positioned in cooperative relationship with said aperture to detect only a linear slice of said specularly-reflected light which has passed through said aperture, said linear slice being oriented substantially parallel to a first direction;
and
(b) said second means further includes third means for moving said bearing ball past said aperture by simultaneously rotating said bearing ball at a given angular velocity about an axis which is oriented in a second direction substantially perpendicular to said first direction while linearly translating said bearing ball at a certain translational velocity in a third direction which is oriented substantially perpendicular to both said first and second directions, and wherein said certain translational velocity has a value which is determined in accordance with a given function of the value of said given angular velocity that results in light specularly-reflected from substantially all points on an entire hemispheric surface of said bearing ball being detected by said one one-dimensional imager in response to said bearing ball, in passing by said aperture, rotating through a predetermined angle which is substantially less in value than 360.degree..

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Dependencies are inferred from the claim text.

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Abstract

In a system for inspecting a bearing ball for the presence of a defect in the normally specularly-reflecting convex surface thereof;

wherein said system comprises first means including a diffuser having an aperture therein for illuminating at least a portion of said convex surface with diffuse light, thereby to reflect a light-contrast pattern of a defect, if present, with respect to a diffuse-light background reflected from said normally specularly-reflecting portion of said surface, and second means, including light-imaging means positioned to be responsive to only that light reflected from said portion of said surface which has passed through said aperture, for detecting the presence of a defect-indicating light-contrast pattern;
the improvement wherein:
(a) said light-imaging means includes at least one one-dimensional imager positioned in cooperative relationship with said aperture to detect only a linear slice of said specularly-reflected light which has passed through said aperture, said linear slice being oriented substantially parallel to a first direction;
and
(b) said second means further includes third means for moving said bearing ball past said aperture by simultaneously rotating said bearing ball at a given angular velocity about an axis which is oriented in a second direction substantially perpendicular to said first direction while linearly translating said bearing ball at a certain translational velocity in a third direction which is oriented substantially perpendicular to both said first and second directions, and wherein said certain translational velocity has a value which is determined in accordance with a given function of the value of said given angular velocity that results in light specularly-reflected from substantially all points on an entire hemispheric surface of said bearing ball being detected by said one one-dimensional imager in response to said bearing ball, in passing by said aperture, rotating through a predetermined angle which is substantially less in value than 360.degree..

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