Tube seam weld inspection device

• US 5,245,409 A
• Filed: 11/27/1991
• Issued: 09/14/1993
• Est. Priority Date: 11/27/1991
• Status: Expired due to Fees

• Current Assignee: ET US Holdings LLC
• Original Assignee: Arvin Industries, Inc. (Cummins Incorporated)
• Inventors: Tobar, Ronald A.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US07/800,853
• Time in Patent Office: 657 Days
• Field of Search: 356/373, 356/375, 356/376, 356/237, 358/101, 358/106
• US Class Current: 356/606
• 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 21/88 Investigating the presence of flaws or contamination
• CPC Class Codes: G01N 21/952 Inspecting the exterior surface of cylindrical bodies or wires G01N21/956 takes precedence

Abstract

The invention provides a method and apparatus for on-line, real-time imaging and inspecting a seam weld on a moving tube in a conventional tube forming environment. The apparatus is in a compact container sealed from workplace contaminants. A planar light source directs a steady plane of light by using mirrors, through an aperture in the container and onto the tube seam at a 45° angle relative to the tube axis, forming a light pattern on the moving tube. A camera in the container images the light, again at 45° relative to the tube axis, and said image is displayed remotely on a conventional video monitor. An operator interprets the light pattern image and adjusts the tube forming apparatus accordingly.

Claims

1. An apparatus for visualizing a longitudinal seam weld on a moving tube in combination with a tube forming machine which forms tube from a strip of flat metal stock, the strip having edges capable of being misaligned when the strip is formed into a tube, the apparatus comprising

means for detecting a misalignment of the edges, the means for detecting including means for projecting a steady plane of light on the tube seam weld as the tube moves longitudinally past said projecting means and means for imaging a reflection of the projected light from the tube seam weld, and

means for displaying the reflection image.

2. The apparatus of claim 1, wherein the projecting means includes a laser light source, lens means through which the laser light is projected, and mirror means for directing the plane of light to intersect the tube seam weld and to direct the reflection of the intersection to the imaging means.

3. The apparatus of claim 2, further comprising means for holding the projecting and imaging means in a fixed position above the longitudinally moving tube.

4. The apparatus of claim 1, wherein the projecting means and the imaging means are in a fixed position relative to the longitudinally moving tube above the seam weld.

5. The apparatus of claim 1, wherein the imaging means includes a camera and a mirror directing the reflection of the projected light from the tube seams weld to the camera.

6. The apparatus of claim 5, further comprising a container housing the projecting means, mirror, and camera.

7. The apparatus of claim 6, wherein the container is formed to include a window opening toward the tube seam weld on the moving tube, the projecting means is located to project the steady plane of light through the window to reach the tube seam weld on the moving tube, and the window is sized to allow the reflection of the projected light to pass from the tube seam weld to the camera through the window.

8. The apparatus of claim 7, further comprising a transparent cover attached to the container and fitted in the window to prevent workplace contaminants from passing through the window to reach the projecting means and the imaging means in the container.

9. The apparatus of claim 4, wherein the imaging means includes a camera and a mirror directing the reflection of the projected light from the tube seam weld to the camera.

10. An apparatus for visualizing a seam weld on a moving tube in combination with a tube forming machine which forms tube from a strip of flat metal stock, the apparatus comprising

a laser light source,

lens means for forming a laser light into a steady plane of light,

mirror means for directing the plane of light to intersect the tube seam weld and to direct the reflection of the intersection to a camera, and

monitor means to display the reflection imaged by the camera.

11. The apparatus of claim 10, further comprising a power supply and a container formed to define an interior region configured to hold the light source, lens means, mirrors, and power supply.

12. The apparatus of claim 11, further comprising means for holding the container in a fixed position above the moving tube.

13. The apparatus of claim 10, further comprising a container housing the laser light source, mirror means, and lens means.

14. The apparatus of claim 13, wherein the container is formed to include a window opening toward the tube seam weld on the moving tube, the laser light source and mirror means are located to project the steady plane of light through the window to reach the tube seam weld on the moving tube, and the window is sized to allow the reflection of the projected light to pass from the tube seam weld to the camera through the window.

15. An apparatus for visualizing a seam weld on a tube moving longitudinally in the direction of its axis, the apparatus comprising

a container formed to include an interior region and an aperture facing the moving tube and its seam weld, the container being positioned in spaced-apart relation to the tube seam weld,

light means for providing a steady planar light, the light means being mounted in the interior region,

means for directing the planar light out of the interior region of the container through the aperture to intersect the tube seam weld to form a light pattern on the tube, the directing means being mounted in the interior region,

means for imaging the light pattern on the tube seam weld, the imaging means being mounted in the interior region,

means for displaying the imaged light pattern connected to the imaging means, the displaying means being positioned outside the container,

source means for supplying electrical power to the light source and the imaging means, the power source means being mounted in the interior region, and

transparent means for covering the aperture to keep workplace contaminants out of the interior region.

16. The apparatus of claim 15, wherein the providing means comprises a laser light and cylindrical lens, and the directing means comprises a plurality of mirrors positioned to direct the steady planar light through the aperture and onto the tube seam weld and to direct the reflection of the points of intersection of the planar light and the tube seam weld into the imaging means.

17. An apparatus for optically determining departures in shape of a workpiece in combination with a manufacturing environment, the apparatus comprising

a container formed to include an interior region protected from the environment and an aperture, the container being positioned in spaced-apart relation to the workpiece,

a planar light source mounted in the interior region,

a camera mounted in the interior region,

a plurality of mirrors arranged in the interior region to direct the planar light through the aperture to intersect the workpiece to form a light pattern on the workpiece and to direct the reflection of the light pattern which passes through the aperture toward the camera,

a power supply mounted in the interior region to provide electrical power to the apparatus,

a transparent aperture cover attached to the container in an aperture-closing position to keep workplace contaminants out of the interior region.

18. An edge alignment measuring system for inspecting alignment of a pair of edges of a strip that abut one another at a seam weld to form a tube in a tube forming machine, the system comprising

means for projecting a steady plane of coherent light across the seam of the tube after it is welded to produce a first light pattern on a first of the edges and a second light pattern on a second of the edges, and

means for displaying the first and second light patterns side-by-side to indicate discontinuity between the first and second light patterns so that misalignment of the first and second edges relative to one another is detected.

19. The system of claim 18, wherein the projecting means includes means for aiming the light source at the tube at about an angle of 45°

relative to the weld seam to produce the first and second light patterns.

20. The system of claim 18, wherein the projecting means includes a laser light source, a cylindrical lens and at least one mirror, and the displaying means includes at least one mirror, a camera, and a viewing screen.

21. The system of claim 20, further comprising a container formed to include an aperture and an interior region configured to hold the light source, the mirrors, and the camera.

22. The system of claim 21, further comprising a transparent means for covering the aperture to allow the laser light to pass out of the interior region through the aperture while keeping workplace contaminants out of the interior region.

28. The method of claim 21, wherein the projecting step includes the step of aiming a light source at the tube at an angle of about 45°

relative to the weld seam to produce the first and second patterns.

29. The method of claim 28, further comprising the step of moving the tube longitudinally under the light patterns.

23. An edge alignment measuring system for inspecting a pair of edges of a strip that abut one another at a seam weld to form a tube, the system comprising

a container formed to include an interior region and an aperture,

means for projecting a steady plane of coherent light across the seam of the tube to produce a first light pattern on a first of the edges and a second light pattern on a second of the edges, where the projecting means is mounted inside the container,

means for displaying the first and second light patterns side-by-side to indicate discontinuity between the first and second light patterns so that a misalignment of the first and second edges relative to one another is detected, and

a transparent aperture cover mounted on the container.

24. The system of claim 23, wherein the projecting means includes a laser light source, a cylindrical lens, and at least one mirror, and the displaying means includes at least one mirror, a camera, and a viewing screen.

25. The system of claim 24, wherein the displaying means mirror and camera are mounted inside the container.

26. The system of claim 25, further comprising means for aiming the light source through the aperture at the tube at an angle of about 45°

relative to the weld seam to produce the first and second light patterns.

27. A method for inspecting the alignment of a pair of edges of a strip that abut one another at a weld seam to form a tube, the method comprising the steps of

projecting a first light pattern on a first of the edges and a second light pattern on a second of the edges,

displaying the first and second light patterns side-by-side to indicate one of a match and a discontinuity to detect a misalignment of the first and second edges relative to one another.

30. The method of claim 27, wherein the displaying step further includes the steps of receiving a reflected image of the first and second light patterns on a mirror and using a camera to transmit the reflected image from the mirror to a viewing screen.

31. A method for inspecting the alignment of a pair of edges of a strip that abut one another at a weld seam to form a tube, the method comprising the steps of

projecting a first light pattern on a first of the edges and a second light pattern on a second of the edges,

moving the tube longitudinally under the light patterns, and

displaying the first and second light patterns side-by-side to indicate discontinuity to detect a misalignment of the first and second edges relative to one another.

32. The method of claim 31, wherein the projecting step includes the step of aiming a light source at the tube at an angle of about 45°

relative to the weld seam to produce the first and second light patterns.

33. The method of claim 31, wherein the displaying step further includes the steps of receiving a reflected image of the first and second light patterns on a mirror while the tube moves and using a camera to transmit the reflected image from the mirror to a viewing screen.

34. A measuring system for inspecting a cut made by a weld bead scarfing tool on a tube moving longitudinally in the direction of its axis at a tube seam extending along the axis and receiving a weld bead, the measuring system comprising

means for projecting a steady plane of coherent light across the cut made by the weld bead scarfing tool to produce a first light pattern on a first side of the tube seam and a second light pattern on a second side of the tube seam, and

means for displaying the first and second light patterns side-by-side to indicate discontinuity between the first and second light patterns so that the depth of the cut made by the weld beam scarfing tool is detected.

35. The system of claim 34, wherein the displaying means includes a camera and a mirror directing a reflection of the first and second light patterns to the camera.

36. The system of claim 35, further comprising a container housing the projecting means, mirror, and camera.

37. The apparatus of claim 36, wherein the container is formed to include a window opening toward the cut made by the weld bead scarfing tool, the projecting means is located to project the steady plane of coherent light through the window to reach said cut, and the window is sized to allow reflection of the first and second light patterns to pass to the camera through the window.