US Patent 10457414 Reduced electromagnetic signature of conforming conical seal fastener systems

A fastener including a sleeve having an elongated portion, a head with a bearing surface, and an internal threaded portion, a core bolt disposed within the sleeve and having a head and a shank portion having an external threaded portion engageable threadedly with the threaded portion of the sleeve. An insert is disposed within the sleeve and surrounds a portion of the core bolt. A seal element is attached to the sleeve and juxtaposed with the bearing surface of the head of the sleeve. The fastener is adapted to be installed in a structure. The electrical contact of the fastener reduces the potential difference between it and the structure, which provides a direct path for continuous propagation of electromagnetic waves, reducing electromagnetic wave scattering and minimizing the electromagnetic signature.