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
B21D11/06—Bending into helical or spiral form; Forming a succession of return bends, e.g. serpentine form
B21D11/07—Making serpentine-shaped articles by bending essentially in one plane
Machine de cintrage de canalisations metalliques de faible diametre agencee notamment pour la realisation de deux cintrages successifs au cours d'une meme operation