Patent US4082936A successfully refreshed from Google Patents.
US4082936A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device and method for heating die
Assignee: Fuji Electric Co Ltd
•
Filing: 1976-06-22
•
Granted: 1978-04-04
•
Expires: 1996-06-22
Abstract
Abstract A device and a method are disclosed for heating a die by induction heating. The die is positioned in a rectangular bobbin so that the direction of the center axis of the die is perpendicular to the direction of an alternating magnetic field produced by an induction-heating coil wound on the bobbin. This eliminates substantially the large temperature difference between the central portion and peripheral portion of the die. Additionally the die may be rotated within the bobbin, or yokes may be provided to increase the uniformity of the magnetic flux distribution over the die.
Inventors
- 👤 Sethuo Aoki
- 👤 Yoshiaki Sogo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:31
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/10; H05B6/101; H05B6/102; H05B6/36; H05B6/365
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
178 words
Apparatus for rapid and uniform pre-heating of a die used for hot extrusion of aluminum alloys, said die having a cylindrical shape with a flat surface and a radial surface, which has a radius which is greater than its thickness and having its extrusion axis along the longitudinal center of said cylinder, comprising: a hollow rectangular bobbin having a longitudinal axis, wherein the short side of said rectangular bobbin is less than the diameter of said die and the long side is greater than the diameter of said die; an induction coil wound upon said bobbin around said longitudinal axis and upon the sides of said rectangular bobbin; a source of power connected to said induction coil for producing a magnetic flux field which is parallel to the longitudinal axis of said bobbin; whereby said die can only be placed in said bobbin with the flat surface of said die parallel to the long side of said bobbin; and whereby said extrusion axis is perpendicular to the longitudinal axis of said coil and perpendicular to said flux field.
Claim 2
Dependent Claim
178 words
Apparatus for rapid and uniform pre-heating of a die used for hot extrusion of aluminum alloys, said die having a cylindrical shape with a flat surface and a radial surface, which has a radius which is greater than its thickness and having its extrusion axis along the longitudinal center of said cylinder, comprising: a hollow rectangular bobbin having a longitudinal axis, wherein the short side of said rectangular bobbin is less than the diameter of said die and the long side is greater than the diameter of said die; an induction coil wound upon said bobbin around said longitudinal axis and upon the sides of said rectangular bobbin; a source of power connected to said induction coil for producing a magnetic flux field which is parallel to the longitudinal axis of said bobbin; whereby said die can only be placed in said bobbin with the flat surface of said die parallel to the long side of said bobbin; and whereby said extrusion axis is perpendicular to the longitudinal axis of said coil and perpendicular to said flux field.
Claim 3
Dependent Claim
19 words
The apparatus of claim 1 further comprising means for rotating said die about its axis while within said bobbin.
Claim 4
Dependent Claim
72 words
The apparatus of claim 2 wherein said means for rotating comprises, a free rotatable die support, a pair of support means within said bobbin for supporting said die support means, rotating shaft engaging means adapted to pass through an opening in the wall of said bobbin to rotatably interlock with said die support and lift said die support off said pair of support means, and means for rotating said shaft engaging means.
Claim 5
Dependent Claim
38 words
The apparatus of claim 1 further comprising high magnetic permeability yoke means positioned at least partially within said bobbin and adjacent the edges of said die nearest the bobbin openings to increase the magnetic flux at said edges.
Claim 6
Independent Claim
160 words
A method of uniform pre-heating of a die which is used for hot extrusion of aluminum alloys, said die having a cylindrical shape with a flat surface and a radial surface, which has a radius which is greater than its thickness and has an extrusion axis along the longitudinal center of said cylinder, comprising the steps of: winding an induction heating coil around the longitudinal axis of a rectangular bobbin and upon the sides of said rectangular bobbin, wherein the short side of said rectangular bobbin is less than the diameter of said die and the long side is greater than the diameter of said die; applying a source of A.C. power to said induction heating coil for producing a magnetic flux which is parallel to the longitudinal axis of said bobbin; placing said die in said bobbin such that said die extrusion axis is perpendicular to the longitudinal axis of said bobbin and between the ends of said bobbin.
Claim 7
Independent Claim
160 words
A method of uniform pre-heating of a die which is used for hot extrusion of aluminum alloys, said die having a cylindrical shape with a flat surface and a radial surface, which has a radius which is greater than its thickness and has an extrusion axis along the longitudinal center of said cylinder, comprising the steps of: winding an induction heating coil around the longitudinal axis of a rectangular bobbin and upon the sides of said rectangular bobbin, wherein the short side of said rectangular bobbin is less than the diameter of said die and the long side is greater than the diameter of said die; applying a source of A.C. power to said induction heating coil for producing a magnetic flux which is parallel to the longitudinal axis of said bobbin; placing said die in said bobbin such that said die extrusion axis is perpendicular to the longitudinal axis of said bobbin and between the ends of said bobbin.
Claim 8
Dependent Claim
20 words
The method of claim 5 further comprising rotating said die during the time said a.c. magnetic field is being applied.
Claim 9
Dependent Claim
29 words
The method of claim 6 wherein said magnetic field is applied for a duration of four minutes or less, and said die is rotated between one and three revolutions.
Claim 10
Dependent Claim
28 words
The method of claim 5 further comprising the step of placing high magnetic permeability yokes adjacent the edges of said die nearest the open ends of said bobbin.
References Cited (Backward Citations)
US1748465A
Cited
US2226446A
Cited
US3394007A
Cited
US3489875A
Cited
US3547715A
Cited
US3965321A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |