# US 2014/0360002 A1 · Method of forming pipe end structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360002 A1 - Document ID: US20140360002A1 - Status: Published application - Kind: A1 - Application number: 14/146,813 - Filed: 2014-01-03 - Published: 2014-12-11 - Earliest claimed: 2013-06-07 - Assignees: Shinko Pipe Kogyo Kabushiki Kaisha - Applicants: Shinko Pipe Kogyo Kabushiki Kaisha - Inventors: Kenichi MORI - Web page: https://patentgrep.com/patent/US20140360002A1 ## CPC - B21D 39/046: {Connecting tubes to tube-like fittings} - B21K 25/00: Uniting components to form integral members, e.g. turbine wheels and shafts, caulks with inserts, with or without shaping of the components (uniting by interference- or press-fitting B23P11/02, B21K19/02) - Y10T 29/49908: Joining by deforming - B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F) - B21K: MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS (making particular articles by working sheet metal without essentially removing material B21D; processing wire B21F; making pins, needles or nails B21G; making particular articles by rolling B21H; forging machines, pressing machines, hammering machines, in general B21J; making chains B21L; plating B23K) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of forming a pipe end structure includes providing a pipe assembly including a metal pipe blank, a ridge, and a tubular fitting, and pressing an inner surface of the pipe blank outwardly. The ridge protrudes outward from an outer surface of the pipe blank. The fitting includes a threaded portion having a thread on an outer surface thereof. The fitting has a first edge and a second edge and is fitted over the pipe blank with the first edge of the fitting being in contact with the ridge protruding from the pipe blank. An inner surface of the pipe blank is pressed outwardly such that a part of the pipe blank protrudes from an outer surface of the pipe blank outwardly at a position adjacent to the second edge of the fitting, thereby forming a locking portion that is in contact with the second edge of the fitting. ## Claims ### Claim 1 A method of forming a pipe end structure, the method comprising; providing a pipe assembly, the pipe assembly including: a metal pipe blank having a through hole extending from one end to another end along an axial direction thereof; a ridge protruding outward from an outer surface of the pipe blank; and a tubular fitting includes a threaded portion having a thread on an outer surface thereof, the fitting having a first edge and a second edge and being fitted over the pipe blank with the first edge of the fitting being in contact with the ridge protruding from the pipe blank; and pressing an inner surface of the pipe blank outwardly such that a part of the pipe blank protrudes from an outer surface of the pipe blank outwardly at a position adjacent to the second edge of the fitting, thereby forming a locking portion being in contact with the second edge of the fitting. ### Claim 2 (depends on 1) The method according to claim 1, wherein the step of pressing of the inner surface includes: inserting a diameter expander configured to expand in a radial direction of the pipe blank into the through hole of the pipe blank; and expanding the diameter expander inserted in the pipe blank in the radial direction of the pipe blank to press the inner surface of the pipe blank outwardly at the position adjacent to the second edge of the fitting. ### Claim 3 (depends on 2) The method according to claim 2, wherein the diameter expander includes a plurality of elastic plates arranged in a tubular shape with a predetermined distance therebetween, each of the elastic plates has a fixed end at one end thereof and a free end at another end thereof, whereby the elastic plates are expandable in a radial direction of the pipe blank, and the inner surface of the pipe blank is pressed outwardly by the other ends of the elastic plates. ### Claim 4 (depends on 1) The method according to claim 1, wherein the step of pressing the inner surface includes: fixing the pipe blank of the pipe assembly to a fixture at a position adjacent to the second edge of the fitting; and inserting a press fit bar into the though hole of the pipe blank from the one end toward the other end of the pipe blank, the press fit bar having an elongated shape and including a press fit portion having an outer diameter larger than an inner diameter of the pipe blank, whereby the inner surface of the pipe blank is pressed outwardly such that the pipe blank has the locking portion. ### Claim 5 (depends on 4) The method according to claim 4, wherein the press fit portion has a cylindrical shape. ### Claim 6 (depends on 4) The method according to claim 4, wherein the press fit portion has a polygonal prism shape. ### Claim 7 (depends on 1) The method according to claim 1, wherein the step of providing the pipe assembly includes: compressing an end portion of the pipe blank in the axial direction of the pipe blank to increase a thickness of the end portion of the pipe blank in a radial direction, whereby the ridge protruding from the outer surface of the pipe blank is formed at the end portion of the pipe blank; and fitting the fitting over the pipe blank so as to be in contact with the ridge at the first edge of the fitting. ### Claim 8 (depends on 1) The method according to claim 1, wherein the step of providing the pipe assembly includes: chamfering an one portion of the pipe blank to have an inclined surface that extends from the inner surface of the pipe blank outwardly at an angle. ### Claim 9 (depends on 3) The method according to claim 3, wherein the step of expanding the diameter expander includes: inserting an diameter adjuster having a cylindrical shape into a space defined by the elastic plates of the diameter expander, the diameter adjuster having an outer diameter larger than that of the diameter expander; and moving the diameter expander in the axial direction of the tube blank toward the one end of the tube blank. ### Claim 10 (depends on 3) The method according to claim 3, wherein each of the elastic plates has a projection at the other end thereof, the projection protrudes radially outwardly from the outer surface of each elastic plate and is configured to press the inner surface of the pipe blank when the diameter expander expands. ### Claim 11 (depends on 4) The method according to claim 4, wherein the step of fixing the pipe assembly to the fixture includes positioning the pipe assembly to have a space between the second edge of the fitting and the fixture, whereby the part of the pipe blank protrudes at a position corresponding to the space to form the locking portion. ### Claim 12 (depends on 4) The method according to claim 4, wherein the step of inserting the press fit bar into the though hole of the pipe blank includes moving the press fit bar inserted in the through hole of the pipe blank until a tip end of the press fit portion reaches a position corresponding to the second edge of the fitting.