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Test Method for Electrical Continuity of a Fastening Assembly

IP.com Disclosure Number: IPCOM000248460D
Publication Date: 2016-Dec-01
Document File: 6 page(s) / 331K

Publishing Venue

The IP.com Prior Art Database

Abstract

In the aeronautical industry, there are various configurations of fastening assemblies used for holding together structural components. Each fastening assembly must display safe electrical continuity characteristics when subjected to electrical current. Qualification testing using designated test assemblies and methods are required in order to demonstrate the electrical continuity characteristics of a fastening assembly. This disclosure introduces a test assembly and method which ensures accuracy and repeatability of the results. The test assembly 10, which is shown in figure 1 above, comprises a conductive plate 11 and a series of conductive L-corners 12, which are attached to the conductive plate 11 by fastening assemblies 13. The conductive plate 11 is a rectangular shape and comprises four parallel rows of holes 16, equidistant spaced apart from each other. Each row has the same number of holes 16. Each row of holes is located at the same distance from the shortest edges of the conductive plate 11. The holes 16 within each row are spaced apart from one another by 50mm. The first row and fourth row of holes 16 are located close to the longest edges of the conductive plate 11. The conductive plate 11 can be either metallic or conductive composite (eg CFRP). An insulating coating is applied to the majority of the surface on both the inner and outer sides of the conductive plate 11. The areas without coating are known as "stripped areas" 15.

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Test Method for Electrical Continuity of a Fastening Assembly

     In the aeronautical industry, there are various configurations of fastening assemblies used for holding together structural components. Each fastening assembly must display safe electrical continuity characteristics when subjected to electrical current. Qualification testing using designated test assemblies and methods are required in order to demonstrate the electrical continuity characteristics of a fastening assembly. This disclosure introduces a test assembly and method which ensures accuracy and repeatability of the results.

Fig 1

     The test assembly 10, which is shown in figure 1 above, comprises a conductive plate 11 and a series of conductive L-corners 12, which are attached to the conductive plate 11 by fastening assemblies 13. The conductive plate 11 is a rectangular shape and comprises four parallel rows of holes 16, equidistant spaced apart from each other. Each row has the same number of holes 16. Each row of holes is located at the same distance from the shortest edges of the conductive plate 11. The holes 16 within each row are spaced apart from one another by 50mm. The first row and fourth row of holes 16 are located close to the longest edges of the conductive plate 11. The conductive plate 11 can be either metallic or conductive composite (eg CFRP). An insulating coating is applied to the majority of the


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surface on both the inner and outer sides of the conductive plate 11. The areas without coating are known as "stripped areas" 15.

     Each L-corner 12 is for example a strip of metal bent at 90 qor composite comprising a short section and a long section. There is the same number of L-corners 12 as there are holes in the second and third rows combined. There is a hole in the centre of the short length of each L-corner and a hole 14 on the long section. An insulating coating is applied to the surface of each L-corner 12, except for the "stripped areas". The "stripped areas" 17 on the L-corners are located on the surface surrounding each hole except for the surface on the short section which contacts the conductive plate.

     The L-corner 12 is installed such that the conductive plate 11 and the short section of the L-corner 12 are in contact and the long section of the L-corner 12 and the conductive plate 11 are perpendicular to one another. Each L-corner 12 is attached to a different hole 16 within the second and third rows on the conductive plate 11 and on the side of the conductive plate which does not have "stripped areas". The long sections of each L-corner 12 are orientated so that they collectively form two parallel lines, which have a smaller separation distance than the second and third rows of holes. A fastening assembly 13 is used to join the short section of each L-corner 12 to the conductive plate 11.

Fig 2

     The fastening assembly 13, which can be seen in figure 2 above, comprises a bolt 18, an insulating sleeve 19, a washer 20, and a nut...