Pipe end expanding or contracting process utilizing ironing
First Claim
1. A process for altering the diameter uniformly over a certain axial length of an end portion of a cylindrical pipe which has a cylindrical inside surface and a cylindrical outside surface, comprising the steps, in the specified order, of:
- (a) applying a diameter modification element having a cylindrical surface of at least said certain axial length to one of said cylindrical surfaces of the pipe over said certain axial length, so as to modify the diameter of said end portion; and
(b) maintaining said diameter modification element in the position it assumed at the completion of step (a), and(c) squeezing said diameter-modified end portion of the pipe between said cylindrical surface of said diameter modification element, and an ironing element which is applied to the other said cylindrical surface of the pipe by moving said ironing element axially over said diameter-modified end portion with a clearance between itself and said cylindrical surface of said diameter modification element which is less than the thickness of said diameter-modified end portion.
0 Assignments
0 Petitions
Accused Products
Abstract
A process and a device for expanding or contracting the end of a pipe are disclosed. First an ironing die or punch is put over or into the end of the pipe. Then the end of the pipe is expanded or contracted by a rod form expanding punch or a tube form reducing die. Then, with this punch or die still in place, the ironing die or punch is pulled over or through the end of the pipe, so as to pinch the wall of the pipe between itself and the punch or die, and thereby the wall of the pipe is ironed so as to release any strains that may have been caused in it by the expanding or contracting process. Thereby more accurate pipe ends can be formed simply and reliably.
10 Citations
7 Claims
-
1. A process for altering the diameter uniformly over a certain axial length of an end portion of a cylindrical pipe which has a cylindrical inside surface and a cylindrical outside surface, comprising the steps, in the specified order, of:
-
(a) applying a diameter modification element having a cylindrical surface of at least said certain axial length to one of said cylindrical surfaces of the pipe over said certain axial length, so as to modify the diameter of said end portion; and (b) maintaining said diameter modification element in the position it assumed at the completion of step (a), and (c) squeezing said diameter-modified end portion of the pipe between said cylindrical surface of said diameter modification element, and an ironing element which is applied to the other said cylindrical surface of the pipe by moving said ironing element axially over said diameter-modified end portion with a clearance between itself and said cylindrical surface of said diameter modification element which is less than the thickness of said diameter-modified end portion. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A process for reducing the diameter uniformly over a certain axial length of an end portion of a cylindrical pipe which has a cylindrical inside surface and a cylindrical outside surface, comprising the steps, in the specified order, of:
-
(a) applying a diameter reducing element having a cylindrical surface of at least said certain axial length to said cylindrical outside surface of the pipe over said certain axial length, so as to reduce the diameter of said end portion; and (b) maintaining said diameter reducing element in the position it assumed at the completion of step (a), and (c) squeezing said diameter-reduced end portion of the pipe between said inner cylindrical surface of said diameter reducing element, and an ironing element which is applied to said cylindrical inside surface of the pipe by moving said ironing element axially through said diameter-reduced end portion with a clearance between itself and said inner cylindrical surface of said diameter reducing element which is less than the thickness of said diameter-reduced end portion.
-
-
7. A process for increasing the diameter uniformly over a certain axial length of an end portion of a cylindrical pipe which has a cylindrical inside surface and a cylindrical outside surface, comprising the steps, in the specified order, of:
-
(a) applying a diameter increasing element having a cylindrical surface of at least said certain axial length to said cylindrical inside surface of the pipe over said certain axial length, so as to increase the diameter of said end portion; and (b) maintaining said diameter increasing element in the position it assumed at the completion of step (a), and (c) squeezing said diameter-increased end portion of the pipe between said outer cylindrical surface of said diameter increasing element, and an ironing element which is applied to said cylindrical outside surface of the pipe by moving said ironing element axially over said diameter-increased end portion with a clearance between itself and said outer cylindrical surface of said diameter increasing element which is less than the thickness of said diameter-increased end portion.
-
Specification