Patent ID: 8420223

Claim:
An insert formed by processing a band-shaped metallic plate, and adapted to be embedded within a long product, wherein said insert includes a large number of insert pieces, each having a rectangular configuration and extending in a width direction of said band-shaped metallic plate, said insert pieces are joined with joining parts in a longitudinal direction of said band-shaped metallic plate at both sides of said insert pieces into a ladder-shaped configuration, a rolling operation and a tension force are applied to said joining parts, said insert pieces define slits between adjacent insert pieces, said slits include first slits, each having a large width in a longitudinal direction of said insert, and second slits, each having a width smaller than that of said first slits in said longitudinal direction, said first slits and said second slits are alternately arranged in said longitudinal direction, said joining parts include first joining parts, each being formed on a side of each of said first slits and having a small width in a width direction of said insert, and second joining parts, each being formed on a side of each of said second slits and having a width larger than that of said first joining parts in said width direction, said first joining parts and said second joining parts are alternately arranged in said longitudinal direction, the width ratio of said insert pieces, said first slits and said second slits in said longitudinal direction is determined to 100:(65˜104):(24˜53), and the width ratio of said first joining parts to said second joining parts in said width direction is determined to 20:(28˜33).