Patent ID: 6339946
Filing Date: 2002-01-22
Classification: B21C,B21D,Y10T

Abstract:
A pipe forming apparatus comprising a pair of bending rolls arranged to work one side of a sheet of feed material, and a counter roll arranged to work the other side of said sheet, said apparatus further comprising:a roll spacing setting device adapted to set the roll spacing of the pair of rolls to a value greater than the sum of the diameter of said counter roll and the diameter of one of said pair of rolls such that the spacing L of the pair of rolls satisfies the following expression: (Dp+Dwl)>L&gE;0.85(Dp+Dwl) wherein Dp represents the outside diameter of the product pipe and Dwl represents the diameter of one of the pair of rolls; and a tightening amount setting device adapted to set the amount of movement of said counter roll relative to said pair of rolls to a value greater than the radius of one of said pair of rolls.