Fastening device

Claim 1

A SHEET METAL FASTENING DEVICE FOR SECUREMENT WITH A THREADED MEMBER, SUCH AS A SCREW, BOLT OR THE LIKE, SAID DEVICE COMPRISING, A GENERALLY FLAT BASE HAVING AN APERTURE THEREIN, THREAD ENGAGING MEANS DEFINED BY MARGINAL PORTIONS OF SAID APERTURE WHICH EXTEND OUTWARDLY FROM SAID BASE FOR ENGAGEMENT WITH THE LOWER SURFACE OF A THREAD OF SAID THREADED MEMBER WHEN INITIALLY INSERTED THROUGH SAID APERTURE, A PAIR OF RESILIENT FINGER PORTIONS MADE INTEGRAL WITH AN EXTENDING UPWARDLY AND ANGULARLY INWARDLY FROM A SAID BASE ON OPPOSITE SIDES OF THE APERTURE THEREIN, THE FREE ENDS OF SAID FINGER PORTIONS BEING AXIALLY OFF-SET RELATIVE TO ONE ANOTHER AND EXTENDING GENERALLY RADIALLY INWARD TOWARD ONE ANOTHER IN OVERHANGING RELATIONSHIP RELATIVE TO SAID THREAD ENGAGING MEANS, SAID THREAD ENGAGING MEANS INCLUDING AN UPWARDLY PROJECTING GENERALLY FRUSTO-CONICAL PROJECTION DEFINING UPPER AND LOWER GENERALLY HELICAL EDGES SEPARATED BY A SLOT PORTION FORMED RADIALLY RELATIVE TO THE APERTURE IN THE SAID BASE PORTION, THE MAXIMUM TRANSVERSE DISTANCE BETWEEN SAID EDGES BEING SUBSTANTIALLY GREATER THAN THE MAXIMUM TRANSVERSE DIMENSION BETWEEN THE FREE ENDS OF SAID FINGER PORTIONS, THE MINIMUM TRANSVERSE DIMENSION BETWEEN SAID EDGES BEING SUBSTANTIALLY GREATER THAN THE ROOT DIAMETER OF SAID THREADED MEMBER ADAPTED TO BE INSERTED THROUGH THE APERTURE IN THE SAID BASE, AND THE MAXIMUM TRANSVERSE DISTANCE BETWEEN THE FREE ENDS OF SAID FINGER PORTIONS BEING SUBSTANTIALLY LESS THAN THE ROOT DIAMETER OF SAID THREADED MEMBER FOR ENGAGEMENT WITH THE UPPER SURFACE OF A THREAD OF THE THREADED MEMBER WHEN INITIALLY INSERTED THROUGH SAID APERTURE, WHEREBY UPON TURNING OF SAID THREADED MEMBER THROUGH SAID APERTURE A FORCE IS IMPARTED BY SAID THREADED MEMBER TO INITIALLY DRAW SAID EDGES DOWNWARDLY AND AXIALLY INTO ENGAGEMENT WITH SAID LOWER THREAD SURFACE, AND SUBSTANTIALLY SIMULTANEOUSLY THEREWITH TO PIVOT SAID FINGER PORTIONS THROUGH A GENERALLY VERTICAL PLANE AND RADIALLY INWARDLY INTO ENGAGEMENT WITH SAID UPPER THREAD SURFACE, SO THAT A COUNTER-FORCE IS IMPARTED BY SAID THREADED MEMBER TO PIVOT SAID FINGER PORTIONS IN GENERALLY OPPOSITE DIRECTIONS TO DRAW SAID EDGES DOWNWARDLY AND AXIALLY INWARDLY, THEREBY TO URGE SAID EDGES AND SAID FINGER PORTIONS INTO TIGHT GRIPPING ENGAGEMENT WITH THE ROOT PORTIONS OF SAID THREADED MEMBER SO THAT IN THE FINAL INSTALLED POSITION, THE AXIAL DISTANCE BETWEEN THE CORRESPONDING AXIALLY ALIGNED POINTS ON SAID EDGES AND THE FREE ENDS OF SAID FINGER PORTIONS IS SUBSTANTIALLY GREATER THAN IN THE SAID INITIALLY INSTALLED POSITION THEREOF.