Method of fabricating a sheet metal joint

Claim 1

A METHOD OF JOINING A FIRST SHEET-LIKE ELEMENT TO A SECOND SHEET-LIKE ELEMENT OF A DEFORMABLE MATERIAL OF SUBSTANTIALLY UNIFORM MINIMUM THICKENSS FOR THE STRENGTH REQUIRED WITHOUT A BREAK IN THE CONTINUITY OF THE SECOND ELEMENT, COMPRISING THE STEPS OF: FORMING AN APERTURE IN THE FIRST ELEMENT, DEFORMING SAID SECOND ELEMENT TO FORM A HOLLOW OFFSET MEMBER INTEGRAL THEREWITH AND OF A LENGTH GREATER THAN THE THICKENSS OF SAID FIRST ELEMENT AND HAVING A TRANSVERSE WALL OF THE THICKNESS AT LEAST EQUAL TO THE THICKNESS OF SAID SECOND ELEMENT; SUPERIMPOSING SAID FIRST ELEMENT ON SAID SECOND ELEMENT WITH THE OFFSET MEMBER EXTENDING THROUGH SAID APERTURE; PLACING A RIGID SUPPORT INTERNALLY OF SAID HOLLOW OFFSET MEMBER TO ENGAGE THE INNER SURFACE OF SAID TRANSVERSE WALL; AND STRIKING THE OUTER SURFACE OF SAID TRANSVERSE WALL WITH AN IMPACT BLOW TO EXTRUDE THE MATERIAL OF SAID WALL OUTWARDLY TO DECREASE THE THICKNESS THEREOF AND SIMULATANEOUSLY FORM AN INTEGRAL, OUTWARDLY-DIRECTED CIRCUMSCRIBING HOLLOW BEAD HAVING A WALL THICKNESS GREATER THAN THE DECREASE WALL THICKNESS OF SAID TRANSVERSE WALL CLAMPING OVERLYING THE EDGE PORTION OF SAID APERTURE TO EFFECT THE JOINTURE WHILE MAINTAINING SAID RIGID SUPPORT IN ENGAGEMENT WITH THE INNER SURFACE OF SAID TRANSVERSE WALL TO HOLD SAID OFFSET MEMBER AGAINST AXIAL COLLAPSE UNDER SAID IMPACT BLOW TO INHIBIT BENDING MOMENTS IN THE WALLS OF SAID OFFSET MEMBER.

Claim 2

A METHOD OF JOINING A FIRST SHEET-LIKE ELEMENT TO A SECOND SHEET-LIKE ELEMENT OF A DEFORMABLE MATERIAL OF SUBSTANTIALLY UNIFORM MINIMUM THICKENSS FOR THE STRENGTH REQUIRED WITHOUT A BREAK IN THE CONTINUITY OF THE SECOND ELEMENT, COMPRISING THE STEPS OF: FORMING AN APERTURE IN THE FIRST ELEMENT, DEFORMING SAID SECOND ELEMENT TO FORM A HOLLOW OFFSET MEMBER INTEGRAL THEREWITH AND OF A LENGTH GREATER THAN THE THICKENSS OF SAID FIRST ELEMENT AND HAVING A TRANSVERSE WALL OF THE THICKNESS AT LEAST EQUAL TO THE THICKNESS OF SAID SECOND ELEMENT; SUPERIMPOSING SAID FIRST ELEMENT ON SAID SECOND ELEMENT WITH THE OFFSET MEMBER EXTENDING THROUGH SAID APERTURE; PLACING A RIGID SUPPORT INTERNALLY OF SAID HOLLOW OFFSET MEMBER TO ENGAGE THE INNER SURFACE OF SAID TRANSVERSE WALL; AND STRIKING THE OUTER SURFACE OF SAID TRANSVERSE WALL WITH AN IMPACT BLOW TO EXTRUDE THE MATERIAL OF SAID WALL OUTWARDLY TO DECREASE THE THICKNESS THEREOF AND SIMULATANEOUSLY FORM AN INTEGRAL, OUTWARDLY-DIRECTED CIRCUMSCRIBING HOLLOW BEAD HAVING A WALL THICKNESS GREATER THAN THE DECREASE WALL THICKNESS OF SAID TRANSVERSE WALL CLAMPING OVERLYING THE EDGE PORTION OF SAID APERTURE TO EFFECT THE JOINTURE WHILE MAINTAINING SAID RIGID SUPPORT IN ENGAGEMENT WITH THE INNER SURFACE OF SAID TRANSVERSE WALL TO HOLD SAID OFFSET MEMBER AGAINST AXIAL COLLAPSE UNDER SAID IMPACT BLOW TO INHIBIT BENDING MOMENTS IN THE WALLS OF SAID OFFSET MEMBER.