B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
B21D11/00—Bending not restricted to forms of material mentioned in only one of groups B21D5/00, B21D7/00, B21D9/00; Bending not provided for in groups B21D5/00 - B21D9/00; Twisting
B21D11/10—Bending specially adapted to produce specific articles, e.g. leaf springs
B21D11/12—Bending specially adapted to produce specific articles, e.g. leaf springs the articles being reinforcements for concrete
Procede et mecanisme pour avancer sur une distance constante des matieres se presentant sous forme de tige, et machines a cintrer comportant un tel mecanisme