Patent ID: 6299399
Filing Date: 2001-10-09
Classification: F16B

Abstract:
A sheet metal fastener, the sheet metal fastener having a first hardness and characterized by a critical hardness higher than the first hardness, the sheet metal fastener comprising:(a) a substantially flat head portion having an upper side, and a lower side, the two sides joined through side bents and being separated by a gap, the upper side having a first hole engageable to an expanding member;(b) a neck having an opening and two side neck portions, the neck extending from the lower side of the substantially flat head portion at a substantially right angle with respect to the substantially flat head portion; and(c) two substantially flat legs extending from the neck, each leg having an inner surface, the two inner surfaces of the two legs being at an initial proximity with each other, the legs having a funnel configuration at a region where the legs start extending from the neck, the legs being expandable in opposite directions upon engaging to the first hole and inserting into the funnel configuration the expansion member;the first hardness being adequately low to allow the head to permanently bow upon application of a pulling force to failure on the expanding member away from the fastener, but not lower than a hardness at which the force to failure is lower than a force to failure of the same fastener having the critical hardness.