Method of forming circularly bent articles, in particular wheel rims, from a straight metal profile strip and apparatus for performing the method

A method of forming circularly bent ring members from elongated metal profiled strip material, particularly for making rims of spoke wheels, such as bicycle wheels, comprising the steps of

• cutting from said strip material strip pieces of a length equal to the circumferential length corresponding to the selected radius of the ring member to be formed;
• forming at each end of said strip pieces a curved end portion having a radius of curvature substantially corresponding to said selected radius;
• feeding said strip piece with one of said curved end portions into a three-roll ring rolling apparatus of the type including two outer forming rolls and a middle forming roll adjustable with respect to said outer rolls,
• said middle forming roll of said rolling apparatus having been set to bend said strip piece to a ring of said selected radius;
• passing said strip piece through said rolling apparatus at least up to the other, trailing curved end portion thereof;
• and
• shifting the middle forming roll of the rolling apparatus from said set position towards the outer forming rolls into a predetermined position corresponding to a substantially bending-free passage of the part of the strip piece already bent to said selected radius;
• and
• passing said curved trailing end portion through said forming rolls in said shifted position of the latter.