US Patent 10066658 Non-rotatable fastener assembly and associated methods

A cap and washer fastener assembly includes a cap with an upper surface and a lower surface with a post extending from the lower surface. The assembly also includes a washer with an upper surface, a lower surface, and a hole. The assembly includes an assembled configuration wherein the post of the cap is inserted into the hole of the washer and a portion of the post is permanently deformed within the cavity. In the assembled configuration, a substrate layer is disposed between the cap and the washer. The cap and washer are configured so they are prevented from rotating relative to one another and relative to the substrate when in the assembled configuration.