INJECTABLE NUT CAP

• US 20140341675A1
• Filed: 05/09/2014
• Published: 11/20/2014
• Est. Priority Date: 05/16/2013
• Status: Active Grant

• Current Assignee: Airbus Operations Limited (Airbus SE)
• Original Assignee: Airbus Operations Limited (Airbus SE)
• Inventors: DOBBIN, Richard
• Granted Patent: US 9,416,811 B2
• Time in Patent Office: Days
• US Class Current: 411/82.1
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: F16B 33/004 Sealing; Insulation by means of washers F16B43/001
• CPC Class Codes: F16B 37/14 Cap nuts; Nut caps or bolt caps
• CPC Class Codes: F16B 43/02 with special provisions for engaging surfaces which are not perpendicular to a bolt axis or do not surround the bolt
• CPC Class Codes: Y10T 29/49982 Coating
• CPC Class Codes: Y10T 29/52 Plural diverse manufacturing apparatus

Abstract

The description provides a method of forming a seal around an end of a fastener protruding from a structure. The cap includes a cap body with a cavity; a sealing material inlet comprising an opening in the cap body; three or more ridges protruding from the cap body into the cavity; and three or more channels between the ridges. The method includes: installing the cap body over the end of the fastener so that it is enclosed within the cavity and contacted by the ridges; injecting sealing material into the cavity via the sealing material inlet so that the sealing material flows along the channels, fills the cavity, contacts the end of the fastener, and contacts the structure; and curing the sealing material to form the seal.

Claims

1. A method of forming a seal around an end of a fastener protruding from a structure, the cap comprising a cap body with a cavity;

a sealing material inlet comprising an opening in the cap body;

three or more ridges protruding from the cap body into the cavity; and

three or more channels between the ridges, the method comprising;

installing the cap body over the end of the fastener so that it is enclosed within the cavity and contacted by the ridges;

injecting sealing material into the cavity via the sealing material inlet so that the sealing material flows along the channels, fills the cavity, contacts the end of the fastener, and contacts the structure; and

curing the sealing material to form the seal.

2. The method of claim 1, wherein the cap body and the cavity terminate at an annular rim;

the cap body is installed over the end of the fastener with an annular gap between the annular rim and the structure; and

the sealing material flows from the sealing material inlet to the annular rim and out of the annular gap to form an annular bead in contact with the structure.

3. The method of claim 1, further comprising fastening the ridges to the end of the fastener with connection features.

4. The method of claim 1, wherein the structure comprises a structural component of an aircraft.

5. A cap for forming a seal around an end of a fastener protruding from a structure, the cap comprising:

a cap body with a cavity for receiving the end of the fastener;

a sealing material inlet comprising an opening in the cap body that is in fluid communication with the cavity, the opening being arranged to interconnect with a sealing material injection device to provide a flow of curable sealing material from the sealing material inlet into the cavity to contact the end of the fastener in the cavity;

three or more ridges protruding from the cap body into the cavity, the ridges being arranged to contact the end of the fastener in the cavity; and

three or more channels between the ridges, the channels being arranged to enable the curable sealing material to flow from the sealing material inlet along the channels into contact with the end of the fastener and into contact with the structure.

6. The cap of claim 5, wherein each ridge comprises a connection feature capable of fastening the cap to the end of the fastener.

7. The cap of claim 6 wherein the connection feature comprises a protrusion, indentation or serration formed in the ridge.

8. The cap of claim 5, wherein the cap body and the cavity terminate at an annular rim, and the channels are arranged to enable the curable sealing material to flow from the sealing material inlet along the channels to the annular rim.

9. The cap of claim 8, wherein the cap body comprises a body portion containing the sealing material inlet;

and an annular skirt which terminates at the annular rim, wherein at least part of the annular skirt bends outwardly from the body portion to increase an angle of the annular skirt relative to a central axis of the cap body.

10. The cap of claim 5, wherein the cap body and cavity terminate at an annular rim lying in a plane, and each ridge extends within the cavity towards the plane of the annular rim then continuous to extend through the plane of the annular rim to a protruding inboard end.

11. The cap of claim 10, further comprising a void between the protruding inboard end of each ridge and the annular rim.

12. The cap of claim 5, wherein the sealing material inlet comprises a collar, boss or other protruding part which is arranged to interconnect with the sealing material injection device.

13. Apparatus for forming a sealed cavity around an end of a fastener protruding from a structure, the apparatus comprising:

a cap according to claim 5; and

a sealing material injection device having a nozzle arranged to interconnect with the sealing material inlet of the cap to direct a flow of curable sealing material into the cavity.

14. A joint comprising:

a structure;

a fastener passing through the structure with an end of the fastener protruding from the structure; and

a cap forming a seal around the end of the fastener, the cap comprising;

a cap body with a cavity receiving the end of the fastener;

a sealing material inlet comprising an opening in the cap body;

three or more ridges protruding from the cap body into the cavity, the ridges contacting the end of the fastener in the cavity;

three or more channels between the ridges; and

a cured sealing material filling the cavity including the channels, the sealing material contacting the end of the fastener and the structure.

15. The joint of claim 14, wherein each ridge comprises a first connection feature and the end of the fastener comprises three or more corresponding second connection features, each first connection feature being interconnected with a second connection feature.

16. The joint of claim 15 wherein the structure is a structural component of an aircraft.

17. The joint of any of claim 14 wherein the end of the fastener protruding from the structure comprises a bolt, a nut screwed onto the bolt, and a washer between the nut and the structure;

and wherein the ridges contact the washer.

18. The joint of claim 17 wherein the nut and washer engage each other via respective spherical surfaces.