Method for forming a through-hole through the circumferential wall of a metal pipe and a metal pipe worked by the said method
First Claim
1. A method for forming a through-hole through a circumferential wall of a metal pipe, said circumferential wall having opposite inside and outside circumferential surfaces and a longitudinal axis, said method comprising the steps of:
- cutting the outside circumferential surface of the metal pipe to form a thin portion extending only partly through the circumferential wall; and
pressing the thin portion with sufficient force for forming a through-hole in the thin portion, and, at the same time, forming a cylindrical burring wall on portions of the circumferential wall of the metal pipe surrounding the through hole.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for forming a through-hole through the circumferential wall of a metal pipe includes the steps of forming at least a thin portion by removing an outside circumferential surface portion of a metal pipe, and forming a through-hole in the thin portion from outside or inside and, at the same time, forming a cylindrical burring wall on the inside or outside circumferential surface side of the metal pipe. The through-hole may be formed by pressing the thin portion from outside with a punch. Alternatively, a preparatory through-hole may be formed together with the thin portion by removing the outside circumferential surface portion of the metal pipe. As a further alternative, the through-hole may be formed from outside with a punch having a larger diameter than the preparatory through-hole, or may be formed by pressing the thin portion from outside or inside by means of fluid pressure or a sphere.
-
Citations
19 Claims
-
1. A method for forming a through-hole through a circumferential wall of a metal pipe, said circumferential wall having opposite inside and outside circumferential surfaces and a longitudinal axis, said method comprising the steps of:
-
cutting the outside circumferential surface of the metal pipe to form a thin portion extending only partly through the circumferential wall; and pressing the thin portion with sufficient force for forming a through-hole in the thin portion, and, at the same time, forming a cylindrical burring wall on portions of the circumferential wall of the metal pipe surrounding the through hole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method for forming a through-hole through a circumferential wall of a metal pipe, said circumferential wall having opposite inside and outside circumferential surfaces, said method comprising the steps of:
-
forming a thin portion in the circumferential wall by cutting the outside circumferential surface only partly through the circumferential wall and thereby removing a portion of the outside circumferential surface of the metal pipe; and forming a through-hole by pressing the thin portion from outside with a punch with sufficient force for simultaneously forming a cylindrical burring wall on an inside circumferential surface of the metal pipe at a location on the inside circumferential surface aligned with the through-hole.
-
-
12. A method for forming a through-hole through a circumferential wall of a metal pipe, said circumferential wall having opposite inside and outside circumferential surfaces, said method comprising the steps of:
-
forming a thin portion in the circumferential wall by cutting the outside circumferential surface substantially transverse to the metal pipe for removing a portion of the outside circumferential surface of the metal pipe; and forming a through-hole by pressing the thin portion with fluid pressure, and, at the same time, forming a cylindrical burring wall on a selected one of the inside or outside circumferential surfaces of the metal pipe.
-
- 13. A metal pipe having a circumferential wall with opposite inside and outside circumferential surfaces, the metal pipe being formed with a thin portion in the circumferential wall formed by cutting the outer circumferential surface transverse to the circumferential wall and removing an outside circumferential surface portion the metal pipe, the thin portion defining a surface area, a through-hole formed through the thin portion of circumferential wall, the through-hole having a cross-sectional area smaller than the area of the thin portion, a burring wall projecting from the circumferential wall of the metal pipe and aligned substantially concentrically with the through-hole.
Specification