Patent ID: 6705143
Filing Date: 2004-03-16
Classification: B21D,Y10T

Abstract:
A method for manufacturing a loading plane boarder frame tube for a chair which comprises:transporting a length of sheet metal continuously through a roller leveler to flatten said strip of sheet metal along the length thereof thereby forming a flat length of sheet metal; roll forming said flat length of sheet metal through a roller calendar to continuously deform a portion of said flat strip along the length thereof so that said sheet metal includes a deformed portion extending along the length thereof and a flat portion extending along either side of said deformed portion; continuously roll forming said sheet metal having said deformed portion through a series of roller calendars to bend said flat portion on either side of said deformed portion thereby forming said length of sheet metal into a tubular configuration having two edges of said strip being adjacent to each other, said roller calendars have a surface profile to deform said length of sheet metal into the shape of a tube having corrugations extending along the length thereof; and joining said edges together by welding or soldering.