Patent ID: 6279369
Filing Date: 2001-08-28
Classification: B21D

Abstract:
A method for bending a pipe with a mandrel inserted thereinto, said pipe having a weld seam extending longitudinally thereof, said weld seam including a bulged portion protruding inwardly of said pipe, said method comprising the steps of:providing first, second and third resinous sheets for forming said mandrel, having an overall thickness corresponding to an inside measurement of said pipe;inserting said first and second resinous sheets into said pipe;fixedly holding proximal ends of said first and second resinous sheets such that an opening is defined between said proximal ends of said first and second resinous sheets;inserting said third resinous sheet into said pipe through said opening such that a surface of one of said first and second resinous sheets comes into intimate contact with said bulged portion;actuating a bender to apply pressure to said pipe to thereby bend said pipe with said first, second and third resinous sheets inserted thereinto;pulling said third resinous sheet out of said bent pipe; andthen, pulling said first and second resinous sheets out of said bent pipe.