Patent ID: 6928732
Filing Date: 2005-08-16
Classification: B21D,F28F,Y10T

Abstract:
1. A method of manufacturing piping having a respective joining portion at both end portions of a pipe in which a diameter expanding portion is formed at an end portion of a pipe, comprising the steps of: a first step of adjusting the pipe length necessary to form the diameter expanding portion before forming the diameter expanding portion, a second step of absorbing an excessive pipe material which is not allowed to adjust the pipe length when forming the diameter expanding portion, wherein the diameter expanding portion is formed in a predetermined shape by means of adjusting the volume of material at the forming end of the pipe without occurring flashes and underfills (thin portions); said first step including: said second step including the steps of: wherein, as a pipe length fluctuation absorbing portion is previously formed in a portion of the inner face of said connector, when a plastic deformation is given to the other end portion of the pipe by said diameter expanding tool so as to form the diameter expanding portion, the excessive pipe material is absorbed by the pipe length fluctuation absorbing portion of said connector and the pipe length is adjusted and automatically conformed to a predetermined length.