Patent US3798954A successfully refreshed from Google Patents.
US3798954A
Expired / Lapsed
US
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Method and apparatus for producing metal tubes by extrusion of a hollow billet
Assignee: Kobe Steel Ltd
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Filing: 1971-11-18
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Granted: 1974-03-26
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Expires: 1991-11-18
Abstract
Abstract Metal tubes are produced by extruding a hollow billet through an annular die opening defined by a die and a movable rod-shaped mandrel having a larger length than the tube to be produced, and by feeding the mandrel rod through the die together with the tube as it is being formed so that the tube as produced has the mandrel rod disposed therein along its entire length, whereby damage to the inner surface of the tube caused by scratching due to relative movement of the mandrel therewith is avoided and tubes having improved inner surface characteristics are obtained.
Inventors
- 👤 A Asari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:43
CPC Classifications
B; B21; B21C; B21C23/00; B21C23/02; B21C23/04; B21C23/08; B21C23/085
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
155 words
A method of producing metal tubes by extruding a hollow billet through a die with the cooperation of a mandrel, comprising the steps of: preparing a hollow billet having a central through opening of predetermined dimensions; applying an external compression force to said hollow billet in an axial direction thereof across its annular cross-section for extruding said hollow billet through an annular die opening defined by a die and a rod-shaped mandrel having a greater length than that desired for a tube being produced; feeding said mandrel rod through said die with said tube being extruded so that substantially no relative motion occurs between said tube and said mandrel rod; cutting the rear end of the tube from the remaining billet by shearing in the axial direction of said tube as said billet is being extruded through said die; and removing said mandrel rod from the said tube after said tube has been completely extruded.
Claim 2
Independent Claim
155 words
A method of producing metal tubes by extruding a hollow billet through a die with the cooperation of a mandrel, comprising the steps of: preparing a hollow billet having a central through opening of predetermined dimensions; applying an external compression force to said hollow billet in an axial direction thereof across its annular cross-section for extruding said hollow billet through an annular die opening defined by a die and a rod-shaped mandrel having a greater length than that desired for a tube being produced; feeding said mandrel rod through said die with said tube being extruded so that substantially no relative motion occurs between said tube and said mandrel rod; cutting the rear end of the tube from the remaining billet by shearing in the axial direction of said tube as said billet is being extruded through said die; and removing said mandrel rod from the said tube after said tube has been completely extruded.
Claim 3
Dependent Claim
49 words
A method according to claim 1, further comprising: charging said hollow billet in a cylindrical chamber axially connected to said die opening; and moving said hollow billet with respect to the wall of said cylindrical chamber as a whole while applying said external compression force as the extrusion proceeds.
Claim 4
Dependent Claim
50 words
A method according to claim 1, further comprising: charging said hollow billet in a cylindrical chamber axially connected to said die opening maintaining said hollow billet substantially stationary with respect to the wall of said cylindrical chamber as a whole while applying said external compression force as the extrusion proceeds.
Claim 5
Independent Claim
181 words
An apparatus for producing metal tubes by extruding a hollow billet through a die with a cooperating mandrel, comprising: a die having an opening therein; a billet container having a cylindrical chamber for receiving a hollow billet; means for supporting said billet container and said die so that said die opening and said cylindrical chamber are axially connected; a rod-shaped mandrel of greater length than that desired of a tube to be produced being movably supported for movement in an axial direction through said billet chamber and said die opening for defining an annular opening between said die and said mandrel; means for applying an axial compression force to a billet in said cylindrical chamber for extruding said billet through said annular opening and moving said rod-shaped mandrel therethrough with said tube being extruded; and a shear mandrel being movable within said means for applying an axial compression force to said billet for applying a shearing force to an inner peripheral portion of said hollow billet in said cylindrical billet chamber as the same is being extruded through said annular opening.
Claim 6
Independent Claim
181 words
An apparatus for producing metal tubes by extruding a hollow billet through a die with a cooperating mandrel, comprising: a die having an opening therein; a billet container having a cylindrical chamber for receiving a hollow billet; means for supporting said billet container and said die so that said die opening and said cylindrical chamber are axially connected; a rod-shaped mandrel of greater length than that desired of a tube to be produced being movably supported for movement in an axial direction through said billet chamber and said die opening for defining an annular opening between said die and said mandrel; means for applying an axial compression force to a billet in said cylindrical chamber for extruding said billet through said annular opening and moving said rod-shaped mandrel therethrough with said tube being extruded; and a shear mandrel being movable within said means for applying an axial compression force to said billet for applying a shearing force to an inner peripheral portion of said hollow billet in said cylindrical billet chamber as the same is being extruded through said annular opening.
Claim 7
Dependent Claim
36 words
An apparatus according to claiM 4, wherein said die and said billet container are firmly connected together and said compression force applying means is an actuator having an annular stem receivable in said cylindrical billet chamber.
Claim 8
Dependent Claim
29 words
An apparatus according to claim 4 wherein said die is movably received in said cylindrical billet chamber and said billet container is axially movable by said axial compression force.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |