Bonded patches with bond line control

Patent metadata

Field	Value
Publication number	US-10022922-B2
Application number	US-201414335269-A
Country	US
Kind code	B2
Filing date	Jul 18, 2014
Priority date	Dec 5, 2008
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A patch may be used to rework a composite structure in the field. The patch is bonded to the structure by a layer of adhesive and includes perforations that allow the escape of air from the adhesive as the patch is compressed against the structure. A spacer may be introduced between the patch and the structure to control the thickness of the adhesive layer.

First claim

What is claimed is:

1. A method of bonding a patch on structure, comprising:
placing the patch on the structure;
placing a layer of bonding adhesive between the patch and the structure;
placing a caul plate over the patch;
pressing the patch against the structure by applying pressure to the caul plate;
using an anti-caul plate to limit the pressure applied to a periphery of the patch by the caul plate; and
placing a non-reversible temperature indication strip on the anti-caul plate.

2. The method of claim 1 , further comprising:
placing a heat pack over the anti-caul plate, the nonreversible temperature indication strip, and the patch.

3. The method of claim 2 further comprising:
activating the heat pack to produce heat.

4. The method of claim 2 further comprising:
prior activating the heat pack, measuring a preactivation temperature of the heat pack with a first reversible temperature indication strip; and
raising the pre-activation temperature if the preactivation temperature is less than a desired temperature.

5. The method of claim 4 further comprising:
activating the heat pack; and
measuring a second temperature of the heat pack with a second, different reversible temperature indication strip.

6. The method of claim 5 further comprising:
if the second temperature fails to reach a second desired temperature, taking an action to increase the second temperature.

7. The method of claim 6 wherein the action comprises replacing the heat pack with a second heat pack and activating the second heat pack.

8. The method of claim 1 , wherein limiting the pressure applied to the periphery of the patch includes a reacting force applied to the caul plate around a perimeter of the caul plate.

9. The method of claim 1 , wherein the reacting force includes placing an anti-caul plate between the caul plate and the structure at the perimeter of the caul plate.

10. The method of claim 1 , further comprising:
placing a spacer between the patch and the structure to maintain the layer of bonding adhesive at a desired thickness.

11. The method of claim 10 , wherein placing a spacer between the patch and the structure includes introducing beads into the adhesive, each of the beads having a dimension generally equal to the desired thickness of the layer of bonding adhesive.

12. The method of claim 10 , wherein placing a spacer between the patch and the structure includes introducing a screen between the patch and the structure having a thickness generally equal to the desired thickness of the layer of bonding adhesive.

13. Apparatus for adhesively bonding a patch on a structure surface, comprising:
a caul plate adapted to be placed on and apply pressure to the patch during a bonding operation; and
an anti-caul plate between the caul plate and the structure surface, the anti-caul plate configured to limit an applied pressure to a periphery of the patch by the caul plate; and
a non-reversible temperature indication strip on the anti-caul plate.

14. The apparatus of claim 13 further comprising:
a heat pack placed over the anti-caul plate.

15. The apparatus of claim 14 further comprising:
a first temperature indicator strip on the heat pack and configured to indicate a pre-activation temperature of the heat pack; and
a second temperature indicator strip on the heat pack and configured to indicate an activated temperature of the heat pack.

16. The apparatus of claim 13 , wherein the anti-caul plate substantially surrounds the patch.

17. The apparatus of claim 13 , wherein:
the anti-caul plate is substantially circular and circumscribes the patch, and a perimeter of the caul plate overlies and engages the anti-caul plate.

18. A method of reworking a composite aircraft structure in the field, comprising:
preparing an area of the structure to be reworked;
forming a patch including forming perforations in the patch;
applying a layer of adhesive to one of the patch and the structure;
controlling a thickness of the adhesive layer by placing a spacer between the patch and the structure;
applying the patch to the structure;
placing a caul plate over the patch;
placing an anti-caul plate between the caul plate and the structure;
placing a non-reversible temperature indication strip on the anti-caul plate;
installing a pressure applicator over the combination of the patch, the caul plate and the anti-caul plate;
using the pressure applicator to apply pressure to the patch through the caul plate;
using the anti-caul plate to limit the pressure applied by the caul plate to a periphery of the patch;
installing a heat pack over the patch; and
using the heat pack to cure the adhesive.

19. The method of claim 11 , wherein placing a spacer between the patch and the structure also includes introducing a screen together with the beads between the patch and the structure, the screen and the beads both having a thickness generally equal to the desired thickness of the layer of bonding adhesive.

Assignees

• Boeing Co

Inventors

• Blanchard Steven Donald
• Akdeniz Aydin
• Spalding John
• Anderson David M
• Evens Michael W

Classifications

• B29C66/472

  said single elements being substantially flat · CPC title

• B29C65/524

  by applying the adhesive from an outlet device in contact with, or almost in contact with, the surface of the part to be joined · CPC title

• C09J5/06

  involving heating of the applied adhesive · CPC title

• B29C65/4875

  being spherical, e.g. particles or powders · CPC title

• B29C65/7826

  said distance pieces being non-integral with the parts to be joined, e.g. particles · CPC title