Method of punching bar codes in a metal strip

摘要

A bar code consists of a plurality of parallel thin and wide bars of respective thin and wide widths and a plurality of thin and wide spaces separating the bars with each of the wide widths being generally equal to a number N times the thin width. Such a code is put on a thin strip by stepping the strip through N punching stations and forming the thin bars by pressing into the strip at the stations a tool having the thin width corresponding to that of the thin bar. Each of the wide bars is formed by first pressing into the strip at a first one of the stations another such thin tool having the relatively thin width to form a respective partial wide bar, and thereafter pressing into the strip at each succeeding station immediately adjacent the partial wide bar another such thin tool having the relatively thin width to widen the partial wide bar until the partial wide bar is of the relatively wide width.