Method of cold forming a self-attaching female fastener element
AssigneeWhitesell International Corporation
InventorsStanley E. Wojciechowski, John M. Parker
Life of this patent
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Abstract
A method of cold forming a self-attaching female fastener (20) which includes deforming a fastener blank (120) having an annular pilot, (122) an annular flange (128) surrounding the pilot and a groove (132) in the flange having cylindrical walls and annular protrusions (152, 154) on the flange and pilot, then deforming the protrusions toward each other to form an annular re-entrant groove (32) having relatively inclined arcuate walls.
Claims18
A method of cold forming a self-attaching female fastener element, comprising the following steps:
- cold forming a female fastener element blank including an annular projecting central pilot portion having an end face, a bore through said pilot portion through said end face, an annular flange portion surrounding said pilot portion having an end face spaced below said end face of said pilot portion, an annular groove in said end face of said flange portion having a bottom wall and generally parallel side walls including an inner side wall adjacent said pilot portion extending generally perpendicular to said end face of said pilot portion and an outer side wall extending generally perpendicular to said end face of said flange portion, a first annular protrusion extending from said end face of said pilot portion adjacent said inner side wall of said annular groove and a second annular protrusion extending from said end face of said flange portion adjacent said outer side wall of said annular groove;
- deforming said first annular protrusion radially outwardly to overly said bottom wall of said groove;
- and
- substantially simultaneously deforming said second annular protrusion radially inwardly to overlie said bottom wall of said groove forming a generally planar end of said flange portion, thereby forming an annular re-entrant groove having a radial opening at said end face of said flange portion having a width less than a radial width of said bottom wall of said groove.
A method of cold forming a self-attaching female fastener element, comprising the following steps:
- cold forming a female fastener element blank including an annular cylindrical central pilot portion having an annular end face, a bore through said pilot portion through said end face, an annular flange portion surrounding said pilot portion having an end face spaced below said end face of said pilot portion, an annular groove in said end face of said flange portion surrounding said pilot portion having a bottom wall and generally parallel side walls including a generally cylindrical inner side wall defining an outer surface of said pilot portion extending generally perpendicular to said end face of said pilot portion and a generally cylindrical outer side wall extending generally perpendicular to said end face of said flange portion, a first annular protrusion having a cylindrical outer surface coaxially aligned with said inner side wall of said groove extending from said end face of said pilot portion and a second annular protrusion having a generally cylindrical inner surface coaxially aligned with said outer side wall of said groove;
- and
- deforming said first annular protrusion radially outwardly to overlie said bottom wall of said groove forming a generally flat end face of said pilot portion;
- and
- substantially simultaneously deforming said second annular protrusion radially inwardly to overlie said bottom wall of said groove, thereby forming a re-entrant groove including an opening at said end face of said pilot portion having a radial width less than a radial width of said bottom wall of said groove.
Dependencies are inferred from the claim text.