Apparatus and method for inspecting ribbed containers

• US 20060006352A1
• Filed: 07/09/2004
• Published: 01/12/2006
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Owens-Brockway Glass Container Incorporated (O-I Glass, Inc.)
• Original Assignee: Owens-Brockway Glass Container Incorporated (O-I Glass, Inc.)
• Inventors: Juvinall, John W.
• Granted Patent: US 7,060,999 B2
• Time in Patent Office: Days
• US Class Current: 250/559.450
• CPC Class Codes: G01B 11/06 for measuring thickness ; e.g. of sheet material thickness measurement by thermal means G01B21/085
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01N 21/9045 Inspection of ornamented or stippled container walls

Abstract

An apparatus for inspecting a container having a central axis and a sidewall with circumferentially extending external ribs. The apparatus includes a light source for directing a line-shaped light beam onto an external surface of the container, a light sensor disposed to receive reflected portions of the line-shaped beam, and an information processor coupled to the light sensor to determine a geometric characteristic of the sidewall as a function of the reflected light energy. The line-shaped light beam preferably has a long dimension parallel to the container axis, and sufficient length to illuminate at least one rib peak and at least one valley between the rib peaks. The sensor may be a linear array sensor that is particularly useful for measuring out-of-round, or an area array sensor for measuring out-of-round and sidewall thickness.

Claims

1. Apparatus for inspecting a container having a central axis and a sidewall with circumferentially extending external ribs, said apparatus including:

a light source for directing a line-shaped light beam onto an external surface of the container, with said line-shaped beam having a long dimension parallel to said central axis and of sufficient length to illuminate a peak of at least one of said ribs and at least one valley adjacent to said one rib,

a light sensor disposed to receive portions of said line-shaped beam reflected from said at least one peak and said at least one valley, and

an information processor coupled to said light sensor to determine a geometric characteristic of said sidewall as a function of said reflected light energy.

2. The apparatus set forth in claim 1 including means for rotating the container around said central axis.

3. The apparatus set forth in claim 2 wherein said sensor is selected from the group consisting of linear array sensors and area array sensors.

4. The apparatus set forth in claim 3 wherein said characteristic is selected from the group consisting of sidewall wobble, sidewall thickness, and radial separation between said at least one peak and said at least one valley.

5. The apparatus set forth in claim 1 wherein said line-shaped light beam has a length sufficient to illuminate at least two of said peaks and the valley between said at least two peaks.

6. Inspection apparatus for inspecting a container having a central axis, a radius, and a sidewall with at least one circumferentially extending rib, said apparatus including:

a light source for directing incident light onto a surface of said sidewall such that it strikes and reflects off of said at least one rib,

a lens system for collecting and refracting reflected light, said reflected light including a nominal reflection axis that is generally centered on a horizontal plane that is perpendicular to said central axis;

a light sensor for receiving refracted light, said refracted light including said nominal reflection axis and is generally centered on said horizontal plane; and

an information processor coupled to said light sensor, said information processor utilizing an image formed on said light sensor by said refracted light to determine at least one geometric characteristic of either said sidewall or said at least one rib.

7. The apparatus set forth in claim 6, wherein said incident light is a line-shaped light beam having a long dimension that is generally parallel to said central axis.

8. The apparatus set forth in claim 6, wherein said nominal reflection axis forms an angle of approximately 45°

with said container radius, and said nominal reflection axis originates from a first reflection position located on said sidewall and terminates at a first image position located on said light sensor.

9. The apparatus set forth in claim 8, wherein said lens system causes those components of said reflected light that are:

i) angled with respect to said nominal reflection axis and ii) originate from said first reflection position, to strike said light sensor at said first image position; and

wherein said lens system causes those components of said reflected light that are;

i) parallel to said nominal reflection axis and ii) originate from a second reflection position that is radially spaced from said first reflection position, to strike said light sensor at a second image position spaced from said first image position.

10. The apparatus set forth in claim 9, wherein said information processor utilizes the distance between said first and second image positions to determine the radial distance between said first and second reflection positions.

11. The apparatus set forth in claim 10, wherein one of said first and second reflection positions is located on a sidewall exterior surface and the other of said reflection positions is located on a sidewall interior surface, such that said distance between said first and second image positions is representative of a sidewall thickness.

12. The apparatus set forth in claim 10, wherein one of said first and second reflection positions is located on a rib peak and the other of said reflection positions is located on a rib valley, such that said distance between said first and second image positions is representative of a radial separation of said at least one rib.

13. The apparatus set forth in claim 9, wherein said information processor monitors any relative movement of either said first or second image positions while said container is being rotating about said central axis.

14. The apparatus set forth in claim 13, wherein one of said first and second reflection positions is located on a generally cylindrical sidewall surface, such that said relative movement of said image position is representative of an out-of-round condition of said cylindrical sidewall surface.

15. The apparatus set forth in claim 13, wherein one of said first and second reflection positions is located on a rib surface, such that said relative movement of said image position is representative of an out-of-round condition of said rib surface.

16. The apparatus set forth in claim 6, wherein said reflected and refracted light include components that are generally aligned along a vertical plane that is perpendicular to said horizontal plane, and said nominal reflection axis originates from a first reflection position located on said sidewall and terminates at a first image position located on said light sensor.

17. The apparatus set forth in claim 16, wherein said lens system causes said components of said reflected light that are angled with respect to said nominal reflection axis to diverge such that they do not strike said light sensor, and

wherein said lens system causes said components of said reflected light that are parallel to said nominal reflection axis to strike said light sensor at said first image position.

18. The apparatus set forth in claim 17, wherein said components of said reflected light that are parallel to said nominal reflection axis originate from reflection positions located on near-vertical surfaces of said container sidewall.

19. The apparatus set forth in claim 6, wherein said image formed on said light sensor comprises a first image element representative of a rib peak and a second image element representative of a rib valley, and

wherein a distance between said first and second image elements is representative of the radial separation of said at least one rib, and any relative movement of said first and second image elements is representative of out-of-round conditions of said at least one rib.

20. The apparatus set forth in claim 6, wherein said image formed on said light sensor comprises a first image element representative of a sidewall exterior surface and a second image element representative of a sidewall interior surface, and

wherein a distance between said first and second image elements is representative of the sidewall thickness, and any relative movement of either said first and second image elements is representative of out-of-round conditions of said sidewall exterior and interior surfaces, respectively.

21. The apparatus set forth in claim 6, wherein said lens system includes either a spherical or a Fresnel lens such that said image formed on said light sensor includes first and second image elements representative of a first rib peak and a first rib valley, respectively, and third and fourth image elements representative of a second rib peak and a second rib valley, respectively.

22. The apparatus set forth in claim 21, wherein said light sensor includes an area array sensor, said first and second image elements are generally aligned at a first axial:

position on said area array sensor and said third and fourth image elements are generally aligned at a second axial position on said area array sensor, said first and second axial positions being spaced from one another.

23. The apparatus set forth in claim 22, wherein the distance between said first and second axial positions is representative of the axial spacing between adjacent ribs.

24. The apparatus set forth in claim 21, wherein said lens system further includes a cylindrical lens and said light sensor includes a linear array sensor, said first and third image elements overlap one another and said second and fourth image elements overlap one another such that all of said image elements are generally aligned along said linear array sensor.

25. A method of inspecting a container sidewall having at least one circumferentially extending rib, comprising the steps of:

(a) providing a light source for directing a line-shaped light beam onto said sidewall such that it strikes at least one rib,

(b) providing a lens system for collecting and directing light reflected from said at least one rib,

(c) providing a light sensor for receiving light directed by said lens system such that it forms an image on said light sensor, said image includes a first image element representative of a first position located on a sidewall surface,

(d) rotating said container about its axis,

(e) monitoring the position of said first image element on said light sensor as said container rotates, and

(f) determining a geometric characteristic of either said container sidewall or said at least one rib based on the position of said first image element.

26. The method set forth in claim 25, wherein step (f) further includes utilizing any relative movement of said first image element to determine if either said container sidewall or said at least one rib has an out-of-round condition.

27. The method set forth in claim 25, wherein said image further includes a second image element, said first image element is representative of a rib peak and said second image element is representative of a rib valley, and

wherein said step (f) further includes utilizing the distance between said first and second image elements to determine the radial separation of said at least one rib.

28. The method set forth in claim 25, wherein said image further includes a second image element, said first image element is representative of a sidewall exterior surface and said second image element is representative of a sidewall interior surface, and

wherein said step (f) further includes utilizing the distance between said first and second image elements to determine the sidewall thickness.

29. The method set forth in claim 25, wherein said method further includes providing a cylindrical lens to compress the light reflected from said at least one rib so that said image can be read by a linear array sensor.