Patent ID: 8651413

Claim:
A lightning-protection fastener that fastens a skin of an aircraft and a structural member positioned inside the skin, the skin being constituted of conductive plastic material as a main element and having a conductive member laminated outside thereof, the lightning-protection fastener comprising: a fastener main body having a head portion, the head portion having an engagement portion formed on an outer circumferential side surface of the head portion; and an insulation layer which is directly melt adhered to and covers an axial end surface of the head portion, and which is also directly melt adhered to, mechanically engaged with and covers the engagement portion formed on the outer circumferential side surface such that the insulation layer is in direct contact with the axial end surface of the head portion and the engagement portion, wherein the engagement portion and the axial end surface of the head portion covered with the insulation layer are insulated from the surrounding conductive member, wherein a circumferential edge portion of the engagement portion has a convex portion along a circumferential direction, the convex portion protruding radially outward, wherein the convex portion has a round shape along the circumferential direction when seen in a longitudinal section view, wherein the fastener main body includes a shaft portion on an opposite side of the head portion with respect to the convex portion, and wherein the circumferential edge portion of the engagement portion has a concave portion along the circumferential direction, the concave portion being depressed radially inward and connecting the convex portion and the shaft portion, the concave portion being located below the convex portion.