Locking hole plug for sealing holes in composite structures

Patent metadata

Field	Value
Publication number	US-2020031069-A1
Application number	US-201816049317-A
Country	US
Kind code	A1
Filing date	Jul 30, 2018
Priority date	Jul 30, 2018
Publication date	Jan 30, 2020
Grant date	—

Abstract

A hole plug that can be used during rework or repair of a composite fiber assembly includes various features that allow placement of a vacuum force to the surface being reworked or repaired. In some implementations, the hole plug can include a plurality of nubs positioned around a shank. The nubs can secure the hole plug to the composite fiber assembly until a cure of an adhesive. The hole plug can further include a plurality of longitudinally oriented grooves extending along the shank and positioned between the plurality of nubs, and can include a notch positioned circumferentially around the shank. The grooves and notch can be used as adhesive carriers that assist with dispersal of a sufficient volume of the adhesive onto other portions of the shank and the composite fiber assembly during insertion of the hole plug into a hole in the composite fiber assembly.

First claim

1 . A hole plug, comprising:
a flange having a first diameter, wherein the flange is positioned at a first end of the hole plug; a bevel extending from, and intersecting, the flange at an angle; a shank extending from the bevel away from the flange to a second end of the hole plug opposite the first end, the shank comprising:
a second diameter that is smaller than the first diameter; and
a plurality of longitudinal grooves defined by the shank and oriented around an exterior of the shank; and
a plurality of nubs positioned on, and extending from, the exterior of the shank, wherein the plurality of nubs are positioned between the plurality of longitudinal grooves.

2 . The hole plug of claim 1 , wherein:
the plurality of nubs each comprise a radius; and a tangent of each radius parallel to a longitudinal axis of the hole plug intersects the flange within the first diameter.

3 . The hole plug of claim 1 , further comprising a circumferential notch defined by the shank, wherein the circumferential notch is positioned between the plurality of longitudinal grooves and the flange.

4 . The hole plug of claim 1 , wherein:
the plurality of nubs each have a first height that is parallel to a longitudinal axis of the hole plug; the plurality of longitudinal grooves each have a second height that is parallel to the longitudinal axis of the hole plug and greater than the first height; and the plurality of longitudinal grooves are positioned closer to the first end and the second end of the hole plug than the plurality of nubs.

5 . The hole plug of claim 4 , wherein the second end of the hole plug comprises a chamfered surface.

6 . The hole plug of claim 5 , wherein the plurality of longitudinal grooves extend into the chamfered surface.

7 . The hole plug of claim 1 , wherein:
each nub defines a radius, such that the plurality of nubs define a plurality of radii; each radius comprises a tangent that is parallel to a longitudinal axis of the hole plug; and each tangent of each radius intersects the flange within the first diameter.

8 . The hole plug of claim 7 , wherein:
the hole plug has a third diameter through a first nub, through the shank, and through a second nub that is opposite the first nub; and the third diameter is less than the first diameter and greater than the second diameter.

9 . The hole plug of claim 1 , wherein the hole plug is formed from a single piece of material.

10 . The hole plug of claim 9 having a surface roughness, wherein an average roughness centerline “R a ” of the surface roughness is from 250 microns (μm) to 400 μm.

11 . The hole plug of claim 10 , wherein the single piece of material is maraging steel.

12 . A composite fiber assembly, comprising:
a composite laminate and a skin overlying the composite laminate, the composite laminate and the skin having a hole therethrough, wherein a first diameter of the hole through the skin is larger than a second diameter of the hole through the composite laminate; a hole plug within the hole, the hole plug comprising:
a flange having a third diameter, wherein the flange is positioned at a first end of the hole plug;
a bevel extending from, and intersecting, the flange at an angle;
a shank extending from the bevel away from the flange to a second end of the hole plug opposite the first end, the shank comprising:
a fourth diameter that is smaller than the third diameter; and
a plurality of longitudinal grooves defined by the shank and oriented around an exterior of the shank; and

a plurality of nubs positioned on, and extending from, the exterior of the shank, wherein the plurality of nubs are positioned between the plurality of longitudinal grooves,
wherein the composite laminate physically contacts the hole plug between the flange and the plurality of nubs.

13 . The composite fiber assembly of claim 12 , wherein:
the plurality of nubs each comprise a radius; and a tangent of each radius parallel to a longitudinal axis of the hole plug intersects the flange within the third diameter.

14 . The composite fiber assembly of claim 12 , wherein the hole plug further comprises a circumferential notch defined by the shank and the circumferential notch is positioned between the plurality of longitudinal grooves and the flange.

15 . The composite fiber assembly of claim 12 , wherein:
the plurality of nubs each have a first height that is parallel to a longitudinal axis of the hole plug; the plurality of longitudinal grooves each have a second height that is parallel to the longitudinal axis of the hole plug and greater than the first height; and the plurality of longitudinal grooves are positioned closer to the first end and the second end of the hole plug than the plurality of nubs.

16 . The composite fiber assembly of claim 15 , the hole plug further comprising a chamfered surface at the second end, wherein the plurality of longitudinal grooves extend into the chamfered surface.

17 . A method for reworking a region of a composite resin assembly having a composite laminate and a skin overlying the composite laminate, the method comprising:
defining a hole within the region of the composite resin assembly, wherein the hole comprises a first diameter within the skin and a second diameter within the composite laminate, and the first diameter is larger than the second diameter; applying an adhesive to a plurality of grooves defined by a shank of a hole plug; fully inserting the hole plug into the hole, wherein the hole plug is recessed within the skin; curing the adhesive; and subsequent to curing the adhesive, completing the reworking of the region.

18 . The method of claim 17 , wherein the completing of the reworking of the region comprises:
applying a vacuum bag to the region subsequent to curing the adhesive; and applying a vacuum force to the region and to the hole plug.

19 . The method of claim 18 , wherein the applying of the vacuum force to the region debulks one or more repair layers overlying the hole plug.

20 . The method of claim 17 , further comprising:
forming a cant on the composite laminate; partially inserting the hole plug into the hole, wherein nubs extending from the shank of the hole plug rest on the cant; and applying the adhesive to a notch that encircles the shank of the hole plug.

Assignees

• Boeing Co

Inventors

• Lewis Melissa H
• Lewis Arne K
• Bertrand Blake A
• Krishnaswamy Pradeep
• Yukseloglu Baris

Classifications

• F16J15/06

  with solid packing compressed between sealing surfaces · CPC title

• B32B3/12

  characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure · CPC title

• F16B11/006

  by gluing (gluing of plastics material B29C65/48) · CPC title

• B64C1/00 Primary

  Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like · CPC title

• B64C2001/0072

  from composite materials · CPC title