Patent ID: 7704175

Claim:
A link plate for a roller chain obtained by shaving a peripheral portion of a roughly punched link plate roughly punched after intermittently, sequentially feeding a band-shaped steel plate to a series of link plate molds consisting of different working molds characterized in that said link plate has a shape comprising a pair of right and left pin holes, a pair of right and left half arcs, which are spaced outwardly from and concentric with said pin holes respectively, and a pair of upper and lower straight line portions connecting both ends of the pair of right and left half arcs, said half arcs having a partial rough surface including at least one of a sag, a rupture surface and a burr, said straight line portions having a shaved smooth surface terminating in first junctions between said straight line portion and said half arcs, and said shaved smooth surface extending along said pair of upper and lower straight line portions and into said half arcs beyond said first junction where the straight line portions merge with the half arcs to a second junction where the shaved smooth surface meets the end of said partial rough surface of the half arc, whereby said half arcs have a central rough surface extending between shaved smooth surfaces adjacent the ends of said half arcs, said second junctions which are between the rough surface and the smooth surfaces in each half arc being connected by an imaginary cord line which passes tangent to the outermost side of said pin hole which is concentric with said half arc.