GB1364260A - Folding strip - Google Patents

Abstract

1364260 Corrugating strip; punching; making heat exchanger fins BRITISH ALUMINIUM CO Ltd 26 Oct 1971 49685/71 Headings B3E B3A and B3W Metal strip is corrugated by passing the strip intermittently through a folding device. Aluminium strip 1 drawn from a coil 2 is passed between guides 3 by means of clamps 4, 8 pneumatically-operated in response to a signal from a micro-switch 6 via a relay valve 7. Clamp members 4a, 4b may comprise punch dies 5 so that the strip may be louvred as it is passed along by the clamps in a step-wise fashion to a folding block. The folding block comprises block halves 9, 10 which have respective inclined faces 9a, 10a which make an angle with the strip of less than 90 degrees. A pivotally reciprocable frame 11, carrying rollers 12, 13 slidable on respective rods 12a, 13a and urged by springs 12b, 13b, operates to cause alternate step-wise corrugating about faces 9a, 10a with rollers 12, 13. The strip then passes through a unit (not shown) in which the number of corrugations per unit length of strip is adjusted. Such corrugated, louvred strip is suitable for use as heat exchanger fins. Both the reciprocable frame and the clamps are driven by a crankshaft 14 and cam 15. The surfaces of blocks 9, 10 are made of material that will not damage or contaminate the strip, e.g. P.V.C. plastics, nylon and for louvred strip the folding block faces and rollers are profiled so that they contact the strip in between the louvred regions. The dies 5, which are readily attachable and detachable, are made of steel or alloy material or tungsten carbide. The width of the strip can be varied and the spacing between the folds can be adjusted.