METHOD FOR MAKING FLANGED BOLT WITH SHAPED HEAD Russian patent published in 2005 - IPC

FIELD: plastic metal working, possibly cold upsetting of fastening parts.

SUBSTANCE: method comprises steps of cutting off blank; preliminarily upsetting bolt head during two transitions for forming smooth portion of blank rod at first transition and forming at second transition bolt head having cylindrical and convex portions; at third transition reducing cylindrical portion of head till diameter equal to described diameter of shaped head of bolt and simultaneously reducing portion of rod for knurling thread; finally forming head at facing upper surface; upsetting flange and knurling thread. At first transition smooth portion of rod is reduced and head is upset. Head includes cylindrical portion whose one base adjoins to truncated cone with small base turned to smooth portion of rod and whose other base adjoins to large base of additional truncated cone of head. At second transition head is upset and spherical convex portion is formed in additional truncated cone and radius zone is formed under head between truncated cone and smooth portion of rod. At third transition part of rod cylindrical portion is reduced by height equal to that of head of bolt having no flange and till diameter equal to inscribed diameter of shaped head of bolt while keeping formed beforehand truncated cone and additional truncated cone having convex spherical part. One more cone is formed in zone passing from smooth portion of rod to portion of rod for knurling thread.

EFFECT: enhanced quality of flanged bolt with shaped head.

5 cl, 1 dwg