INTEGRAL SEALANT O-RING

• US 20190323539A1
• Filed: 04/10/2019
• Published: 10/24/2019
• Est. Priority Date: 04/18/2018
• Status: Active Grant

• Current Assignee: Textron Innovations Incorporated (Textron Inc)
• Original Assignee: Textron Aviation, Inc. (Textron Inc)
• Inventors: Clothier, Brent
• Granted Patent: US 11,346,387 B2
• Time in Patent Office: Days
• CPC Class Codes: B64C 3/34 Tanks constructed integrally with wings, e.g. for fuel or water
• CPC Class Codes: F16B 33/004 Sealing; Insulation by means of washers F16B43/001
• CPC Class Codes: F16B 5/02 by means of fastening members using screw-thread F16B5/0004 takes precedence; construction of screw-threaded connections F16B25/00 - F16B39/00
• CPC Class Codes: F16B 5/0642 the plates being arranged one on top of the other and in full close contact with each other

Abstract

An integral sealant O-ring for sealing fasteners in mating surfaces of a fuel tank includes a fastener hole through an inner mating surface and an outer mating surface, the fastener hole has a chamfer along a fay interface between the mating surfaces. A layer of sealant is applied along the fay interface, and upon tightening of the fastener, the inner and outer mating surfaces are pulled together squeezing the sealant into the chamfer and forming an integral sealant O-ring around the fastener. A method of forming an integral sealant O-ring includes forming a chamfer in a first mating surface substantially concentric with a fastener hole, applying a layer of sealant along the first mating surface, pulling together the first mating surface with a second mating surface by tightening a fastener to trap sealant within the chamfer for forming an integral sealant O-ring.

Claims

1. An integral sealant O-ring for sealing fasteners in mating surfaces of a fuel tank, comprising:

an inner mating surface having an inner hole for receiving a fastener;

an outer mating surface having an outer hole for receiving the fastener, the outer hole being aligned with the inner hole;

the fastener having a shank portion aligned through the inner hole and the outer hole and a head portion protruding adjacent the inner mating surface for tightening the fastener;

a chamfer around one of the inner hole or the outer hole along a fay interface between the inner mating surface and the outer mating surface;

a layer of sealant applied along the fay interface; and

the integral sealant O-ring is formed in the chamfer by the layer of sealant upon tightening of the fastener.

2. The fastener seal of claim 1, wherein a width of the chamfer is less than or equal to half of the distance that the head portion overlaps the shank portion.

3. The fastener seal of claim 1, wherein a depth of the chamfer is less than or equal to half of the thickness of the outer mating surface.

4. The fastener seal of claim 1, wherein a cone angle of the chamfer is between about fifteen degrees to about sixty degrees with respect to a longitudinal direction of the shank portion.

5. The fastener seal of claim 1, wherein the integral sealant O-ring prevents fuel leakage from a wet wing aircraft along the shank portion of the fastener without a daub seal applied to the head portion of the fastener.

6. A fastener seal for sealing fasteners in mating surfaces of a fuel tank, comprising:

an inner mating surface having an inner hole for receiving a fastener;

an outer mating surface having an outer hole for receiving the fastener, the outer hole being aligned with the inner hole;

the fastener having a shank portion aligned through the inner hole and the outer hole and a head portion protruding adjacent the inner mating surface for tightening the fastener;

a first chamfer in the outer mating surface adapted for receiving a tapered end of the fastener;

a second chamfer, concentric with the first chamfer, the second chamfer having a narrower cone angle than that of the first chamfer such that a radial channel is formed around a portion of the shank and a portion of the tapered end; and

a layer of sealant applied along the second chamfer such that an integral sealant O-ring is formed in the radial channel.

7. The fastener seal of claim 6, wherein a cone angle of the first chamfer has a wider cone angle than the second chamfer.

8. The fastener seal of claim 7, wherein a cone angle of the first chamfer is about forty-five degrees and a cone angle of the second chamfer is about thirty degrees.

9. The fastener seal of claim 6, wherein a bearing area of the fastener 120 is reduced by less than fifty percent due to the second chamfer.

10. The fastener seal of claim 6, wherein the integral sealant O-ring prevents fuel leakage from a wet wing aircraft along the shank portion of the fastener without a daub seal applied to the head portion of the fastener.

11. The fastener seal of claim 6, further comprising a third chamfer in one of the inner mating surface or the outer mating surface along a fay interface therebetween, wherein sealant applied along the fay interface forms an additional integral sealant O-ring in the third chamfer upon tightening of the fastener.

12. A method of forming an integral sealant O-ring for sealing fasteners of mating surfaces of a fuel tank, comprising:

forming a chamfer in a first mating surface substantially concentric with a first hole, the first hole adapted for receiving a fastener through the first mating surface;

applying a layer of sealant along the first mating surface;

arranging a second mating surface substantially in parallel with the first mating surface, the second mating surface having a second hole aligned with the first hole;

inserting the fastener through the first hole and the second hole;

pulling together the first mating surface with the second mating surface by tightening the fastener, thereby trapping a portion of the sealant within the chamfer for forming an integral sealant O-ring around a shank portion of the fastener.

13. The method of claim 12, further comprising cleaning the fastener prior to inserting through the first hole and second hole to ensure proper adhering of the sealant with the shank portion.

14. The method of claim 12, wherein forming the chamfer is performed by drilling without lubrication to provide a clean surface for sealant adhesion.

15. The method of claim 12, further comprising preventing fuel leakage from a wet wing aircraft along the shank portion of the fastener by forming the integral sealant O-ring and without applying a daub seal to the head portion of the fastener.