Patent ID: 6546774
Filing Date: 2003-04-15
Classification: B21D,F28F

Abstract:
A method of making an elongated lanced and offset heat transfer fin of a desired length and having â€œnâ€  legs, the method comprising the steps of:a) advancing a continuous elongated, generally planar strip of indeterminate length of thin metal in its direction of elongation along a forming path; b) in the forming path, i) firstly, forming n rows of spaced short slits in the strip, with the rows extending generally in the direction of elongation of the strip and the slits being generally transverse thereto; ii) forming crowns in the parts of the strip between adjacent slits in each row with alternating parts in a row having crowns extending in one direction and the remaining parts having crowns extending in the opposite direction; iii) preforming the two innermost legs by bending the parts of the two innermost rows at the opposed ends of the slits and the crowns of each row to partially form the legs; iv) preforming the next two innermost legs by bending the parts of the next two innermost rows at the opposed ends of the slits and the crowns of each row; v) repeating step iv) until the two outermost legs have been preformed; vi) finally forming the two innermost legs to be generally transverse to the plane of the strip by further bending said parts of the two innermost rows at the opposed ends of the slits and the crowns of each of the two innermost rows; vii) finally forming the next two innermost legs to be generally transverse to the plane of the strip by further bending said parts of the next two innermost rows at the opposed ends of the slits and the crowns of each of the next two innermost rows; viii) repeating step vii) until said two outermost legs have been finally formed; c) sizing the legs; and d) cutting the strip into fins of a desired length.