Self-retained sheet metal fastener

Claim 1

A ONE PIECE SHEET METAL FASTENER INCLUDING AN APERTURE BASE INTEGRAL LEGS EXTENDING FROM OPPOSED SIDES OF SAID BASE AND SUBSTANTIALLY NORMAL THERETO PRESENTING IN CROSS SECTION A SUBSTANTIALLY U-SHAPED FORM, A FLANGE EXTENDING LATERALLY OUTWARDLY FROM THE TERMINAL EDGES OF SAID LEGS, A SCREW ACCOMMODATING MEMBER STRUCK FROM SAID BASE MEMBER SO AS TO PROVIDE SAID BASE APERTURE, SAID MEMBER BEING APERTURED TO PROVIDE THREADED CONVOLUTION RECEIVING MEANS IN SUBSTANTIAL COAXIAL ALIGNMENT WITH SAID BASE APERTURE, INTEGRAL MEANS EXTENDING BETWEEN SAID LEGS AND STRUCK OUT FROM SAID BASE AND LEGS FOR SECURING SAID MEMBER AND BASE IN SPACED RELATION, AND PERIPHERAL WORK IMPINGING MEANS ALONG THE INTERNAL MARGIN OF THE BASE INCLUDING A PLURALITY OF PERIPHERALLY SPACED TOOTH ELEMENTS PROJECTING RADIALLY INWARDLY INTO THE APERTURE OF SAID BASE TO PERMIT INSERTION OF A WORKPIECE FROM ONE SIDE OF SAID FASTENER, THE APERTURE IN SAID STRUCK OUT MEMBER BEING ADAPTED TO ACCOMMODATE A SCREW MEMBER INSERTED FROM THE OPPOSITE SIDE OF THE FASTENER, THE DIAMETER OF THE BASE APERATURE BEING SUBSTANTIALLY LARGER THAN THE SCREW ACCOMMODATING APERTURE OF THE STRUCK OUT APERATURE.