Method of securing fasteners to sheet material

Claim 1

The method of securing to a relatively thin metal sheet a metal element having a relatively thick pilot portion and having flange means thereon projecting laterally outward from the top region of the pilot portion to establish a mounting surface for abutment against a surface of the thin metal sheet, which method comprises the steps of: piercing the thin metal sheet with the pilot portion of the metal element to thereby excise a slug from the thin metal sheet and force the metal element to a position relative to the thin metal sheet in which said mounting surface of the metal element is in engagement with the surface of the thin metal sheet; and during the movement of the metal element relative to the thin metal sheet, cutting metal segments from restricted and separated portions of said pilot portion of the metal element while continuously forcing the cut metal segments laterally away from the pilot portion without the complete severance thereof from the metal element and on the side of the thin metal sheet opposite the side against which the mounting surface bears, displacing metal of the thin metal sheet laterally by the lateral displacement of the metal segments from the pilot portion, spreading and forming the displaced metal and that of said segments cut from the pilot portion in transverse direction to provide bosses wider than the metal segments cut from the pilot portion, and then compressing the metal of the bosses against the surface of the thin metal sheet opposite the mounting surface while simultaneously effecting compression of the metal of the bosses inwardly of the bosses in transverse and generally radial directions to increase the solidity thereof.

Claim 2

The method of securing to a relatively thin metal sheet a metal element having a relatively thick pilot portion and having flange means thereon projecting laterally outward from the top region of the pilot portion to establish a mounting surface for abutment against a surface of the thin metal sheet, which method comprises the steps of: piercing the thin metal sheet with the pilot portion of the metal element to thereby excise a slug from the thin metal sheet and force the metal element to a position relative to the thin metal sheet in which said mounting surface of the metal element is in engagement with the surface of the thin metal sheet; and during the movement of the metal element relative to the thin metal sheet, cutting metal segments from restricted and separated portions of said pilot portion of the metal element while continuously forcing the cut metal segments laterally away from the pilot portion without the complete severance thereof from the metal element and on the side of the thin metal sheet opposite the side against which the mounting surface bears, displacing metal of the thin metal sheet laterally by the lateral displacement of the metal segments from the pilot portion, spreading and forming the displaced metal and that of said segments cut from the pilot portion in transverse direction to provide bosses wider than the metal segments cut from the pilot portion, and then compressing the metal of the bosses against the surface of the thin metal sheet opposite the mounting surface while simultaneously effecting compression of the metal of the bosses inwardly of the bosses in transverse and generally radial directions to increase the solidity thereof.

Claim 7

The method of securing a metal element having a relatively thick pilot portion of predetermined shape and size with bottom cutting edges thereon and laterally projecting flanges at opposite sides of the top region thereof to a relatively thin metal sheet with the aid of a die having top cutting edges at the tops of wall surfaces of an opening conforming in shape and size to major peripheral portions of said cutting edges on the pilot portion, and which top cutting edges of the die are separated peripherally of the die by major arcuate recesses which span over 180* and extend outwardly of the die from said opening, the bottoms of which recesses are adjoined by arcuate steps which project laterally into the die opening and form minor segments which span less than 180* of a semispherical dimple surface at the bottom of each recess and slope downwardly and outwardly from said die opening as well as upwardly and inwardly of the die adjacent said die opening to acute angular wedge-type cutting edges extending into the die opening, said method comprising the steps of placing the metal sheet between the pilot portion of the metal element and the top of the die, applying force to the metal element to force the pilot portion thereof toward said die opening and through the metal sheet to sequentially cut said metal sheet at the top cutting edges of the die, deform the metal of the sheet at said recesses, effect a laterally outward flow of metal cut from the pilot portion of the metal element at said acute angular wedge-type cutting edges and laterally outward of the die opening across the semi-spherical dimple surfaces at the bottoms of the recesses as a result of pressure exerted through said metal element and lateral components exerted by said dimple surfaces, and then effecting compression of deformed metal from the sheet and metal cut from the pilot portion of the metal element against one surface of the metal sheet in a direction axial to the die opening as a result of direct pressure and in directions radial to said semi-spherical dimple surfaces as the result of force components exerted through said semi-spherical dimple surfaces while said laterally projecting flanges on the metal element are firmly pressed against an opposing surface of the metal sheet.

Claim 8

The method of securing a metal element having a relatively thick pilot portion of predetermined shape and size with bottom cutting edges thereon and laterally projecting flanges at opposite sides of the top region thereof to a relatively thin metal sheet with the aid of a die having top cutting edges at the tops of wall surfaces of an opening conforming in shape and size to major peripheral portions of said cutting edges on the pilot portion, and which top cutting edges of the die are separated peripherally of the die by major arcuate recesses which span over 180* and extend outwardly of the die from said opening, the bottoms of which recesses are adjoined by arcuate steps which project laterally into the die opening and form minor segments which span less than 180* of a semispherical dimple surface at the bottom of each recess and slope downwardly and outwardly from said die opening as well as upwardly and inwardly of the die adjacent said die opening to acute angular wedge-type cutting edges extending into the die opening, said method comprising the steps of placing the metal sheet between the pilot portion of the metal element and the top of the die, applying force to the metal element to force the pilot portion thereof toward said die opening and through the metal sheet to sequentially cut said metal sheet at the top cutting edges of the die, deform the metal of the sheet at said recesses, effect a laterally outward flow of metal cut from the pilot portion of the metal element at said acute angular wedge-type cutting edges and laterally outward of the die opening across the semi-spherical dimple surfaces at the bottoms of the recesses as a result of pressure exerted through said metal element and lateral components exerted by said dimple surfaces, and then effecting compression of deformed metal from the sheet and metal cut from the pilot portion of the metal element against one surface of the metal sheet in a direction axial to the die opening as a result of direct pressure and in directions radial to said semi-spherical dimple surfaces as the result of force components exerted through said semi-spherical dimple surfaces while said laterally projecting flanges on the metal element are firmly pressed against an opposing surface of the metal sheet.

Claim 9

The method of securing to a relatively thin metal sheet a metal element having a relatively thick pilot portion of predetermined shape and size and also having flanges projecting laterally at the top region thereof to establish mounting surfaces, said method being effected with the aid of a die having an opening of a size and shape related to that of the pilot portion and including recesses spaced peripherally of the opening and adjoining steps which project into the die opening, and which recesses and steps together define concave dimple-type semi-spherical surfaces with wedge-shaped cutting edges facing upwardly and extending angularly into the die opening in directions to slope downwardly and outwardly for substantial distances away from the opening, said method comprising the steps of placing the metal sheet between the metal element and the die with the pilot portion of the metal element aligned with the opening in the die, applying force to the metal element to drive the pilot portion of the metal element through the metal sheet and into the die opening until said mounting surfaces are in firm engagement with one surface of the metal sheet, and thereby effecting the sequential steps of excising a slug from the metal sheet, deforming metal of said sheet in said recesses, cutting metal segments from the pilot portion of the metal element with said wedge-shaped cutting edges while forcing the metal thus cut from the pilot portion outwardly and progressively away from the pilot portion across the concave dimple-type surfaces and into said recesses, and then compressing the metal in said recesses both axially against the surface of the sheet opposite that engaged by said mounting surfaces to form bosses integral with the pilot portion of the metal element and also to effect radial inward compression of the metal of each of the bosses to effect securement of the metal element in place on the metal sheet.

Claim 10

The method of securing to a relatively thin metal sheet a metal element having a relatively thick pilot portion of predetermined shape and size and also having flanges projecting laterally at the top region thereof to establish mounting surfaces, said method being effected with the aid of a die having an opening of a size and shape related to that of the pilot portion and including recesses spaced peripherally of the opening and adjoining steps which project into the die opening, and which recesses and steps together define concave dimple-type semi-spherical surfaces with wedge-shaped cutting edges facing upwardly and extending angularly into the die opening in directions to slope downwardly and outwardly for substantial distances away from the opening, said method comprising the steps of placing the metal sheet between the metal element and the die with the pilot portion of the metal element aligned with the opening in the die, applying force to the metal element to drive the pilot portion of the metal element through the metal sheet and into the die opening until said mounting surfaces are in firm engagement with one surface of the metal sheet, and thereby effecting the sequential steps of excising a slug from the metal sheet, deforming metal of said sheet in said recesses, cutting metal segments from the pilot portion of the metal element with said wedge-shaped cutting edges while forcing the metal thus cut from the pilot portion outwardly and progressively away from the pilot portion across the concave dimple-type surfaces and into said recesses, and then compressing the metal in said recesses both axially against the surface of the sheet opposite that engaged by said mounting surfaces to form bosses integral with the pilot portion of the metal element and also to effect radial inward compression of the metal of each of the bosses to effect securement of the metal element in place on the metal sheet.