Electro-optical sensor systems for thread and hole inspection

A method for inspecting threaded objects comprising:

• providing a sensor unit, said sensor unit comprising light source means for illuminating threads of a threaded object, lens means for forming an image of at least a portion of the threads of a threaded object illuminated by said light source means, and means for detecting said image, said detecting means comprising a light sensitive member having a light sensitive area sufficiently small to resolve the individual threads in the image of the threads of an illuminated threaded object, said light sensitive member having an output signal responsive to light incident on said light sensitive area;
• moving a threaded object relative to said sensor unit such that the light from said light source means illuminates said threads whereby an image of at least a portion of the threads illuminated by said light is formed by said lens means, and is incident upon said detecting means whereby said output signal is produced;
• and
• analyzing said output signal to determine the quality of said threads.

Apparatus for detecting the presence and for determining the depth of a blind hole comprising:

• light source means for projecting a spot of light onto the surface of an object and onto the bottom of a blind hole in said surface;
• lens means for forming an image of said spot of light;
• detector means for detecting said image, said detector means comprising a first light detector positioned to detect the image of said spot of light on said surface and a second light detector positioned to detect the image of said spot of light on the bottom of said blind hole, said first and second light detectors each having an output signal responsive to light incident thereon;
• and
• means for analyzing the output signal of said first light detector to determine the presence of said hole and for analyzing the output signal of said second light detector to determine the depth of said hole.

A method of detecting the presence of and for determining the depth of a blind hole in an object comprising:

• providing a sensor unit, said sensor unit comprising light source means for projecting a spot of light onto the surface of an object and onto the bottom of a blind hole in said surface, lens means for forming an image of said spot of light, and detector means for detecting said image, said detector means comprising a first light detector to detect the image of said spot of light on said surface and a second light detector positioned to detect the image of said spot of light on the bottom of said blind hole, said first and second light detectors each having an output signal responsive to light incident thereon;
• moving an object having a blind hole in a surface thereof relative to said light source whereby said spot of light is first incident upon said surface on one side of said blind hole then incident upon the bottom of said hole, and then incident upon said surface on the other side of said blind hole;
• analyzing the output signal of said first detector to determine the presence of said hole in said surface;
• and
• analyzing the output signal of said second detector to determine the depth of said hole.