Concrete form snap-tie rod and method of forming the head therefor

Claim 1

A method of forming a head of polygonal peripheral shape on an end of a carbon steel snap-tie, said method comprising: a. moving the end of the rod into a contour forming die having an internal peripheral shape conforming substantially to the external peripheral shape of the head to be formed on the rod and against a heading tip juxtaposed to one side of the die, said die having an interior surface defined by a plurality of flat sides with adjacent sides defining intersecting planes having an included angle therebetween of greater than 90* and less than 120* and said sides including therebetween a diameter greater than the diameter of the end of the rod; b. heating the end of the rod to forging temperature within the die by establishing an electrical resistance heating circuit through the end of the rod and the heading tip; and, c. upsetting the end of the rod against the heading tip by a single stroke sufficient to expand the rod into contact with the die to form a head on the rod with flat peripheral surfaces substantially conforming to the flat sides defining the interior surface of the die and with rounded peripheral apex surfaces between said flat surfaces, the volume of the end so upset being such as to not flare out around the die.

Claim 2

A method of forming a head of polygonal peripheral shape on an end of a carbon steel snap-tie, said method comprising: a. moving the end of the rod into a contour forming die having an internal peripheral shape conforming substantially to the external peripheral shape of the head to be formed on the rod and against a heading tip juxtaposed to one side of the die, said die having an interior surface defined by a plurality of flat sides with adjacent sides defining intersecting planes having an included angle therebetween of greater than 90* and less than 120* and said sides including therebetween a diameter greater than the diameter of the end of the rod; b. heating the end of the rod to forging temperature within the die by establishing an electrical resistance heating circuit through the end of the rod and the heading tip; and, c. upsetting the end of the rod against the heading tip by a single stroke sufficient to expand the rod into contact with the die to form a head on the rod with flat peripheral surfaces substantially conforming to the flat sides defining the interior surface of the die and with rounded peripheral apex surfaces between said flat surfaces, the volume of the end so upset being such as to not flare out around the die.