Abstract: A nail fastener assembly for attaching thin metal sheets includes an axially extending nail with a conically shaped shank having ballistic-like tip at its leading end and a head at its trailing end. A disk is fitted on the leading end of the shank with a sleeve secured on the shank between the disk and the head. When the nail is driven by a setting tool, the sleeve acts on the disk in the region of the tip, so that the transmission of all forces acts on an annular radially outer surface on the leading surface of the disk. The leading end surface of the disk has a radially inner conically shaped first recess and an annular second recess encircling the outer edge of the first recess and spaced inwardly from the radially outer edge of the disk. Accordingly, the radially outer contact surface bears against the metal sheet being attached and provides high transverse stresses.

Abstract: A fastening element assembly is made up of a nail-like fastening element and a deformable sleeve displaceably secured on the fastening element shank. The assembly is used to secure sheet metal plates to a base material of variable strength. At its leading end the sleeve has an outwardly extending flange. When the assembly is driven into a receiving material or base, the sleeve is displaced in the rearward direction along the shank toward the trailing head on the fastening element. The shank widens conically toward the head. As the sleeve is displaced rearwardly, it is radially expanded. When the trailing end of the sleeve contacts the head, the sleeve collapses or is deformed in the axial direction in the manner of an accordian. Excess energy applied to the assembly during the driving step is converted into deformation work acting on the sleeve.