Fastening system for thin sheet metal has screw with hexagonal head passing through hole in strap formed by dimpling and cutting thin sheet

摘要

The sheet has a dimpled portion with a central hole and two straight parallel cuts which separate two segments of the circle from a central strap, which is further depressed. The hexagonal head of the screw can fit between the two segments so that it is prevented from turning and there is a split washer which can bear against the strap and the segments to hold the screw in position.