US4009601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for bending a double pipe
Assignee: SHIMIZU SEISAKUSHO KK
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Filing: 1976-01-21
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Granted: 1977-03-01
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Expires: 1996-01-21
Abstract
Abstract A method of and apparatus for bending a double pipe comprising inserting a smaller diameter pipe into a pipe of larger diameter and coupling the two pipes together at one end, inserting a inner metal core and an outer metal core respectively into the inside of the inner pipe and between the inner and outer pipes, inserting the double pipe into a bending mold, fixing the pipe on a turntable on which the bending mold is rigidly affixed, fixing a section of the double pipe near the end into which the metal cores were inserted thus blocking movement of the fixed section in the radial direction, and driving the turntable in a radial direction while keeping the metal cores in a fixed position and applying a bending force on the double pipe toward the bending mold while pushing the inner pipe in an axial direction from the end into which the metal core was inserted.
Inventors
- 👤 Sadaichi Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:40
CPC Classifications
B; B21; B21D; B21D9/00; B21D9/05; B21D9/07; B21D9/073; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49861; Y10T29/49879
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
An apparatus for bending a double pipe comprising: a turntable; a bending mold fixed to said turntable; a means coupled to said bending mold for fixing one end of a double pipe to prevent movement in a radial direction; an inner metal core located laterally to said bending mold and adapted to be inserted into one end of a inner pipe of a double pipe; a cylindrical outer metal core coaxial with said inner core inserted into one end of an outer pipe of a double pipe between said inner and outer pipes; and a means for exerting a force on an inner pipe in an axial direction while a double pipe is being bent whereby contact between said inner and outer pipes is avoided.
Claim 2
Independent Claim
125 words
An apparatus for bending a double pipe comprising: a turntable; a bending mold fixed to said turntable; a means coupled to said bending mold for fixing one end of a double pipe to prevent movement in a radial direction; an inner metal core located laterally to said bending mold and adapted to be inserted into one end of a inner pipe of a double pipe; a cylindrical outer metal core coaxial with said inner core inserted into one end of an outer pipe of a double pipe between said inner and outer pipes; and a means for exerting a force on an inner pipe in an axial direction while a double pipe is being bent whereby contact between said inner and outer pipes is avoided.
Claim 3
Dependent Claim
57 words
A apparatus for bending a double pipe according to claim 1 wherein said outer and inner metal cores are inserted into a double pipe such that one end thereof is adjacent the point of contact between the double pipe and said bending mold and lies in a plane passing through the axis of rotation of said turntable.
Claim 4
Dependent Claim
32 words
An apparatus for bending a double pipe according to claim 3 wherein said outer metal core has a concentric circular form having its center at the axis of rotation of said turntable.
Claim 5
Independent Claim
136 words
A method for bending a double pipe comprising: coupling the inner and outer of the double pipe together at one end; inserting the end of the double pipe into a bending mold fixed to a turntable; fixing the end of said double pipe opposite the coupled together end to prevent movement in a radial direction; inserting an inner metal core and a cylindrical outer metal core into respectively said inner pipe and said outer pipe between said inner and outer pipes, said cores being inserted until the end is adjacent a contact point between said double pipe and said bending mold; rotating the turntable thereby bending the double pipe along the contour of the bending mold; and applying a force to rear of said inner pipe in an axial direction while said turntable is being rotated.
Claim 6
Independent Claim
136 words
A method for bending a double pipe comprising: coupling the inner and outer of the double pipe together at one end; inserting the end of the double pipe into a bending mold fixed to a turntable; fixing the end of said double pipe opposite the coupled together end to prevent movement in a radial direction; inserting an inner metal core and a cylindrical outer metal core into respectively said inner pipe and said outer pipe between said inner and outer pipes, said cores being inserted until the end is adjacent a contact point between said double pipe and said bending mold; rotating the turntable thereby bending the double pipe along the contour of the bending mold; and applying a force to rear of said inner pipe in an axial direction while said turntable is being rotated.
Claim 7
Dependent Claim
52 words
A method for bending a double pipe according to claim 4 wherein the magnitude of the force applied to the rear of said inner pipe is between 20 and 100 percent of the force acting in the axial direction of the pipe due to the force applied to bend the double pipe.
References Cited (Backward Citations)
US3546917A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-02-29 | 1980-08-30 | 1981-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-29 | 1984-08-30 | 1985-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-29 | 1988-08-30 | 1989-03-01 | $7700.00 | Window Closed / Lapsed |