LIGHTNING PROTECTION FASTENER AND MOUNTING METHOD THEREOF

• US 20130186552A1
• Filed: 01/10/2013
• Published: 07/25/2013
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Aircraft Corporation (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Aircraft Corporation (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Nishimura, Wataru, Watanabe, Yasunori, Hashigami, Toru, Rikukawa, Hiroshi, Asahara, Yuji, Yamakoshi, Hideo, Iyomasa, Atsuhiro, Tarumi, Takeyasu, Imamura, Hideo, Taniguchi, Naoki
• Granted Patent: US 8,717,736 B2
• Time in Patent Office: Days
• US Class Current: 156/92
• 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 39/225 by means of a settable material
• 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

Abstract

A sealant 34 filled into a cap 30A is caused to overflow through both an opening in a first end portion 30a of the cap 30A and a through-hole 40 of the cap 30A when the cap 30A is pressed against a fastener member 25. With regard to the cap 30A, a ratio between inside diameter D1 of the opening on the side of the first end portion 30a and hole diameter D2 of the through-hole 40 in the second end portion 30b is set as follows: 0.10≦D2/D1 ≦0.27.

Claims

1. A lightning protection fastener comprising:

a fastener member for fastening a second member to a first member which constitutes an airframe of an aircraft and the fastener member having a shaft which penetrates the first member and the second member and protrudes on a side of at least one of the first member and the second member;

a fastening member mounted on the fastener member shaft which protrudes on the side of at least one of the first member and the second member;

a cap made of an insulating material and the cap being mounted so as to cover the fastener member shaft and the fastening member, the fastener member shaft protruding on the side of at least one of the first member and the second member; and

a sealant made of an insulating material and filled into the cap to close a space between the cap and the fastener member and the fastening member,

wherein the cap includes an opening adapted to house the fastener member shaft and the fastening member as well as a through-hole formed in a wall surface of the cap, and

inside diameter D1 of the cap on the side of an end portion of the opening which faces the first member or the second member and hole diameter D2 of the through-hole are configured to satisfy

0.10≦

D2/D1≦

0.27.

2. The lightning protection fastener according to claim 1, wherein the through-hole is formed in a top of the cap or in a location closer to the top of the cap than the fastening member.

3. The lightning protection fastener according to claim 1, wherein a tubular member extending outwardly of the cap is formed around the through-hole.

4. The lightning protection fastener according to claim 3, wherein:

the tubular member is formed integrally with the cap; and

a groove continuous in a circumferential direction is formed at a root of the tubular member.

5. The lightning protection fastener according to claim 1, wherein an openable and closable lid adapted to cover the through-hole is formed on the cap.

6. The lightning protection fastener according to claim 5, wherein outside diameter of the lid is smaller than inside diameter of the through-hole, and part of the lid in a circumferential direction is integrally coupled to the cap.

7. The lightning protection fastener according to claim 2, wherein the through-hole and lid are formed on the top of the cap.

8. A method for mounting the lightning protection fastener according to claim 1, comprising the steps of:

passing the fastener member through the first member and the second member, protruding the fastener member shaft on a side of at least one of the first member and the second member, and mounting the fastening member on the fastener member shaft; and

mounting the cap so as to cover the fastener member shaft and the fastening member, the fastener member shaft protruding on the side of at least one of the first member and the second member and the cap having been filled with the sealant in advance, wherein

in the step of mounting the cap, the sealant filled into the cap is caused to spill out of the cap through both the opening and the through-hole by pressing the cap toward the fastener member shaft and the fastening member.