Patent ID: 7290423

Claim:
A method for roller hemming together edges of at least two metal panels to form an edge hemmed panel assembly, the method comprising: positioning at least first and second metal panels with edges aligned in mated face engagement, the first panel having a flange portion bent from the mated edge of the first panel across and beyond the mated edge of the second panel; providing hemming apparatus having a roller hemming portion operable in a process capable of completing a finished edge hem in at least one pass of relative motion along the length of the mated edge of the panels wherein the flange portion of the first panel is folded over in a gradual bend from one end to another of the mated edges to effectively engage the flange with an outer side of the mated edge portion of the second panel and thereby maintain the panels in an assembly; wherein the hemming portion included a mount carrying annealing apparatus and at least a final roller positioned to serially operate on the flange portion as the mount is traversed along the length of the mated edges such that the annealing apparatus heats and quenches the flange prior to bending toward the second panel and the final roller finishes folding of the flange against the second panel to form the finished hem, the gradual folding of the flange being completed in at least one pass of the mount with the rollers moving from one end to an opposite end of the mated edges of the panels; and operating the apparatus according to said process to complete a finished hem of the mated edges of the panels; wherein the annealing apparatus includes an induction coil and an air quenching knife positioned to carry out further method steps of sequentially induction heating and then air cooling the flange portion to relieve internal stresses in the flange portion prior to bending by the final roller; and wherein the apparatus includes pivoting arms supporting the induction coil, and guide rollers operative to maintain the induction coil in a desired position relative to the flange portion to provide a desired heating of the flange portion prior to the quenching step.