Patent ID: 8366364

Claim:
A piercing fastener being attachable to a panel by penetration of its continuous planar surface and having means for attachment of a device thereto, comprising: a barrel having an axial throughbore and an outside surface extending from a top end to an open bottom end thereof, said throughbore including an inner wall of increased diameter at a bottom portion thereof terminating at a sharp circular edge for penetrating said panel; a reinforcement collar located at the base of the barrel extending radially from said barrel's outside surface, said collar being the largest diameter of said fastener and having an annular top surface adapted to receive a downward pressing force; an annular displacer located immediately below said collar and including an annular bottom surface for forcibly deforming material of said panel downward; an undercut groove of lesser inside diameter than said displacer located on said outside surface immediately below said displacer adapted to receive a cold flow of panel material deformed by said displacer; a plurality of axially extending circumferential teeth located immediately below said undercut on said outside surface, said teeth extending to a greater diameter than said undercut but being of lesser diameter than said displacer; and a chamfer extending downward and inwardly from said teeth terminating at a circular cutting lip at the bottom end of the fastener, said fastener having features for penetrating into but not through said panel.