Method and inspection head apparatus for optically measuring geometric dimensions of a part

• US 20090103111A1
• Filed: 10/23/2007
• Published: 04/23/2009
• Est. Priority Date: 10/23/2007
• Status: Active Grant

• Current Assignee: GII Acquisition LLC
• Original Assignee: GII Acquisition LLC
• Inventors: Spalding, John D.
• Granted Patent: US 7,738,121 B2
• Time in Patent Office: Days
• US Class Current: 356/638
• CPC Class Codes: G01B 11/028 by measuring lateral position of a boundary of the object G01B11/022, G01B11/024, G01B11/04 take precedence
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence

Abstract

A method and inspection head apparatus for optically measuring geometric dimensions of a part are provided. The method optically measures the geometric dimensions of a part having a part axis at an inspection station. The method includes directing an array of spaced planes of radiation at the part so that the part occludes each of the planes of radiation at spaced locations along the part axis to create a corresponding array of unobstructed planar portions of the planes of radiation. Each of the unobstructed planar portions contains an amount of radiation which is representative of a respective geometric dimension of the part. The method further includes measuring the amount of radiation present in each of the unobstructed planar portions.

Claims

1. A method for optically measuring geometric dimensions of a part having a part axis at an inspection station, the method comprising:

directing an array of spaced planes of radiation at the part so that the part occludes each of the planes of radiation at spaced locations along the part axis to create a corresponding array of unobstructed planar portions of the planes of radiation wherein each of the unobstructed planar portions contains an amount of radiation which is representative of a respective geometric dimension of the part; and

measuring the amount of radiation present in each of the unobstructed planar portions.

2. The method as claimed in claim 1, wherein the number of planar portions is twice the number of the planes of radiation.

3. The method as claimed in claim 1, wherein each of the planes of radiation is directed at the part from a different azimuthal direction relative to the part axis.

4. The method as claimed in claim 3, wherein the planes of radiation have a substantially uniform azimuthal spacing relative to the part axis.

5. The method as claimed in claim 1, wherein none of the planes of radiation are coplanar.

6. The method as claimed in claim 1, wherein the planes of radiation are equally spaced.

7. The method as claimed in claim 1, wherein the radiation is laser radiation.

8. The method as claimed in claim 7, wherein the laser radiation is visible.

9. The method as claimed in claim 1, wherein the part is a threaded part.

10. The method as claimed in claim 1, wherein adjacent pairs of unobstructed planar portions created from the same planes of radiation are coplanar.

11. An inspection head apparatus for optically measuring geometric dimensions of a part having a part axis at an inspection station, the apparatus comprising:

a container;

a plurality of radiation sources mounted within the container for directing an array of spaced planes of radiation at the part so that the part occludes each of the planes of radiation at spaced locations along the part axis to create a corresponding array of unobstructed planar portions of the planes of radiation wherein each of the unobstructed planar portions contains an amount of radiation which is representative of a respective geometric dimension of the part; and

a plurality of receiver modules mounted within the container for measuring the amount of radiation present in the unobstructed planar portions.

12. The apparatus as claimed in claim 11, wherein the container has an opening extended completely therethrough which allows relative movement of the part through the opening.

13. The apparatus as claimed in claim 11, wherein each of the radiation sources includes a laser for producing a laser beam, each of the lasers being mounted within the container at a height offset from a base height of the container and wherein each of the heights is different from each of the other heights.

14. The apparatus as claimed in claim 13, wherein each of the radiation sources includes a transmitter module having a first set of optical components and a first optical mount mounted within the container for supporting its respective first set of optical components within the container so that each first set of optical components converts a laser beam produced by its respective laser into one of the planes of radiation.

15. The apparatus as claimed in claim 14, wherein the first optical mounts are substantially identical.

16. The apparatus as claimed in claim 11, wherein each of the receiver modules includes a second set of optical components and a second optical mount mounted within the container for supporting its respective second set of optical components within the container.

17. The apparatus as claimed in claim 16, wherein each second set of optical components includes a focusing component for focusing an unobstructed planar portion into an image plane and a photodetector for converting light energy in the image plane into an electrical signal.

18. The apparatus as claimed in claim 17, wherein each second set of optical components includes a telecentric aperture stop supported by its second optical mount at a height matched to the height of its unobstructed planar portion between its focusing component and its photodetector.

19. The apparatus as claimed in claim 16, wherein each second set of optical components includes a pair of focusing components for focusing unobstructed planar portions created from the same plane of radiation into a pair of spaced image planes and a pair of spaced photodetectors for converting light energy in the spaced image planes into electrical signals.

20. The apparatus as claimed in claim 19, wherein each second set of optical components includes a pair of telecentric aperture stops supported by its second optical mount at a height matched in the height of the adjacent unobstructed planar portions between the focusing components and the photodetectors.

21. The apparatus as claimed in claim 16, wherein the second optical mounts are substantially identical.

22. The apparatus as claimed in claim 14, wherein the first optical mounts are mounted immediately adjacent one another on a base plate of the container which defines the base height of the container.

23. The apparatus as claimed in claim 16, wherein the second optical mounts are mounted immediately adjacent one another on a base plate of the container which defines the base height of the container.

24. The apparatus as claimed in claim 11, wherein the planes of radiation are parallel to a mounting surface of the container and wherein the radiation sources and receiver modules are mounted on the mounting surface.