Method and apparatus for reworking structures

Patent metadata

Field	Value
Publication number	US-9579873-B2
Application number	US-201313761785-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 7, 2013
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

An area of a structure is reworked from one side of the structure using resin infusion of a dry fiber patch. Entrapped air and excess resin is removed from the patch during the infusion process by inserting a vacuum device into the patch, and forcing the area resin through the vacuum device.

First claim

What is claimed is:

1. A method of reworking an area of a structure, comprising:
placing a patch on the structure, including placing an inner side of the patch against the structure, wherein placing the patch on the structure includes:
placing a dry fiber patch on the structure, and
placing a bond enhancing layer between the dry fiber patch and the structure;

inserting a vacuum source into the patch from an outer side of the patch, the vacuum source comprising an open tip of a hollow needle;
flowing resin onto the outer side of the patch; and,
using the vacuum source to force resin through the patch to an inner side of the patch.

2. The method of claim 1 , further comprising:
placing a vacuum bag over the outer side of the patch.

3. The method of claim 2 , further comprising:
removing the vacuum source from the patch after the patch has been infused with resin.

4. The method of claim 3 , further comprising:
forming a scarf partially through a thickness of the structure, and
wherein placing the fiber patch on the structure includes placing the inner side of the patch against a bottom of the scarf, and inserting the vacuum source includes inserting the hollow needle down through a thickest part of the patch to substantially the bottom of the scarf.

5. The method of claim 4 , wherein inserting the vacuum source further includes inserting the hollow needle through the vacuum bag, and forming a substantially vacuum tight seal between the hollow needle and the vacuum bag.

6. The method of claim 5 , wherein removing the vacuum source from the patch includes:
withdrawing the hollow needle from the patch and from the vacuum bag, and
sealing a hole in the vacuum bag resulting from penetration of the vacuum bag during insertion of the hollow needle through the vacuum bag.

7. The method of claim 1 , wherein inserting the vacuum source into the patch includes:
inserting a plurality of hollow needles through the patch at spaced apart locations over an area of the patch.

8. The method of claim 1 , wherein using the vacuum source to force resin through the patch to an inner side of the patch comprises creating a pressure differential between the inner and outer sides that drives resin to flow to the inner side of the patch.

9. The method of claim 1 , wherein flowing resin onto the outer side of the patch includes:
placing a resin distribution tube on the outer side of the patch beneath the vacuum bag, and
supplying resin into the resin distribution tube.

10. A method of reworking an area of a structure, comprising:
forming a scarf partially through a thickness of the structure;
fabricating a dry fiber patch having an inner side and an outer side;
installing the fiber patch within the scarf, including placing the inner side of the fiber patch against the structure at a bottom of the scarf, wherein placing the fiber patch within the scarf includes:
placing a dry fiber patch on the structure within the scarf, and
placing a bond enhancing layer between the dry fiber patch and the structure;

installing a vacuum bag over the outer side of the fiber patch;
inserting a vacuum device from the outer side of the fiber patch through the fiber patch, the vacuum device comprising an open tip of a hollow needle;
infusing the fiber patch with resin by introducing resin on the outer side of the fiber patch;
using the vacuum device to force resin through the fiber patch to the inner side of the fiber patch; and,
removing the vacuum device from the fiber patch after the fiber patch has been infused with resin.

11. The method of claim 10 , wherein inserting the vacuum device through the fiber patch includes inserting the hollow needle through the vacuum bag and the fiber patch until a tip of the hollow needle has substantially penetrated a thickest part of the fiber patch.

12. The method of claim 11 , further comprising:
forming a substantially vacuum tight seal between the vacuum bag and the hollow needle.

13. The method of claim 11 , further comprising:
withdrawing the hollow needle from the fiber patch and from the bag after the fiber patch has been infused with resin.

14. The method of claim 13 , further comprising sealing a hole in the vacuum bag resulting from withdrawal of the hollow needle from the vacuum bag.

15. The method of claim 10 , wherein infusing the fiber patch with resin is performed by introducing resin under controlled atmospheric pressure on the outer side of the fiber patch.

16. The method of claim 15 , wherein introducing resin includes:
placing a spiral wrap around a periphery of the outer side of the fiber patch for introducing the resin on the outer side of the fiber patch, and
coupling the spiral wrap with a reservoir of resin adapted to supply resin to the spiral wrap at partial atmospheric pressure.

17. The method of claim 10 , wherein compacting the fiber patch is performed and maintained after the vacuum device has been removed from the fiber patch.

18. The method of claim 11 , further comprising:
removing excess resin from the fiber patch through the tip of the hollow needle.

19. A method of reworking an area of a composite structure from only one side of the composite structure, comprising:
forming a scarf in one side of the composite structure;
installing a fiber patch in the scarf, including placing an inner side of the fiber patch in contact with the structure, wherein installing the fiber patch in the scarf includes:
placing a dry fiber patch on the structure in the scarf, and
placing a bond enhancing layer between the dry fiber patch and the structure;

installing a vacuum bag over an outer side of the fiber patch;
inserting a hollow needle through the vacuum bag and down into the fiber patch until a tip of the needle is near the inner side of the fiber patch;
forming a seal between the hollow needle and the vacuum bag;
coupling the hollow needle with a vacuum reservoir;
compacting the fiber patch;
infusing the fiber patch with resin by flowing resin onto an outer side of the fiber patch and using the hollow needle and the vacuum reservoir to force the resin to the inner side of the fiber patch;
removing excess resin in the fiber patch through the tip of the hollow needle;
removing the hollow needle from the fiber patch after the fiber patch has been infused with resin;
sealing a hole in the vacuum bag caused by penetration of the vacuum bag by the hollow needle; and
compacting the resin infused fiber patch by evacuating the vacuum bag.

20. The method of claim 19 , wherein the fiber patch has an area of maximum thickness, and inserting the hollow needle is performed by passing the tip of the hollow needle through the area of maximum thickness of the fiber patch.

21. The method of claim 19 , further comprising:
withdrawing the hollow needle from the fiber patch and from the vacuum bag, and
sealing a hole in the vacuum bag resulting from the withdrawal of the hollow needle from the vacuum bag.

22. The method of claim 19 , wherein flowing resin into the outer side of the fiber patch and using the hollow needle and vacuum reservoir force the resin to the inner side of the fiber patch is performed using controlled partial atmospheric pressure resin infusion.

23. The method of claim 1 , wherein the patch comprises layers of dry fiber reinforcement, and wherein the outer side is parallel to the layers.

Assignees

• Boeing Co

Inventors

• Hanks Dennis James
• Woods Jack A

Classifications

• B29C70/443

  and impregnating by vacuum or injection · CPC title

• B32B38/08 Primary

  Impregnating · CPC title

• B29C73/12

  Apparatus therefor, e.g. for applying (B29C73/30 takes precedence) · CPC title

• Y10T156/1798

  with liquid adhesive or adhesive activator applying means · CPC title

• B29C73/10

  using patches sealing on the surface of the article (B29C73/14 takes precedence) · CPC title