Patent ID: 6840571

Claim:
A method of forming tubular bars comprising the steps of: (a) continuously providing an elongated sheet of material of a predetermined width taken from the group comprising stainless steel, high carbon steel, cold roll steel and aluminum; and (b) continuously moving the sheet of material through roll forming assemblies which have shapes that as the sheet of material is passed therethrough, the material is gradually and progressively formed in succession into tubular members, each tubular bar having an elongated metal body with a pair of interconnected side walls with inner and outer surfaces, each side wall having a flange extending towards the other side wall and terminating in a lip along the longitudinal edge thereof, said lips and flanges extending the entire length of the metal body, with the flanges overlying one another, with the inner surface of one flange in surface to surface contact with the outer surface of the other flange, the outer surface of one side wall having an elongated groove extending from one end of the metal body to the other end, said groove receiving the elongated lip provided on the flange connected to the other side wall whereby said last mentioned lip and groove forms an integral rolled locking mechanism which extends the entire length thereof and holds the tubular bar in tension.