Patent US6185196B1 successfully refreshed from Google Patents.
US4808779A
Expired / Lapsed
US
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Single cycle, single frequency induction contour hardening process
Assignee: INDUSTRIAL ELECTRIC HEATING A CORP OF OHIO
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Filing: 1988-04-07
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Granted: 1989-02-28
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Expires: 2008-04-07
Abstract
Abstract The present invention discloses a method for contour hardening a gear by means of induction heat treatment in a single heating cycle, using a single frequency of induction current. The typical frequency of alternating current is 50 KHz, applied in a single heating cycle for a duration in the general range of 0.3-1.0 seconds, having a power in the typical range of 200-1,000 KW. The power level required for any particular gear is typically 120% to 150% that required in the final heating step of a hardening process which requires preheating. An important advantage of the process disclosed herein is the elimination of the need to preheat the gear, yet contour harden tooth and root regions of said gear with a single heating cycle of a single frequency heating current.
Inventors
- 👤 Gary C. Cogley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:17
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/32; H; H05; H05B; H05B6/00; H05B6/02; H05B6/36; H05B6/40; H05B6/405; Y; Y02; Y02P; Y02P10/00; Y02P10/25
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
A process of contour hardening a gear by induction heat treatment, the process using a single frequency of induction current without preheating said gear, comprising the steps of: (a) mounting said gear on a rotatable spindle concentric with, and substantially surrounded by, the inductor coil of a high-frequency current generator; (b) rotating said gear in close proximity to said inductor coil, and concentric therewith, at a sufficiently rapid rate such that said gear completes at least three complete rotations in the period during which said inductor coil is supplied with current; (c) supplying said inductor coil with alternating current of predetermined frequency and current in a single pulse of current for a predetermined duration; (d) quenching said gear with cooling means providing thereby case hardening of said gear.
Claim 2
Dependent Claim
128 words
A process of contour hardening a gear by induction heat treatment, the process using a single frequency of induction current without preheating said gear, comprising the steps of: (a) mounting said gear on a rotatable spindle concentric with, and substantially surrounded by, the inductor coil of a high-frequency current generator; (b) rotating said gear in close proximity to said inductor coil, and concentric therewith, at a sufficiently rapid rate such that said gear completes at least three complete rotations in the period during which said inductor coil is supplied with current; (c) supplying said inductor coil with alternating current of predetermined frequency and current in a single pulse of current for a predetermined duration; (d) quenching said gear with cooling means providing thereby case hardening of said gear.
Claim 3
Dependent Claim
22 words
A process of contour hardening a gear as in claim 1 wherein said alternating current has a frequency of approximately 50 kilohertz.
Claim 4
Dependent Claim
32 words
A process of contour hardening a gear as in claim 2 wherein said alternating current has a value so as to produce a dissipation of electrical power in the range 200-1,000 kilowatts.
Claim 5
Dependent Claim
25 words
A process of contour hardening a gear as in claim 3, wherein said predetermined duration of said single pulse is in the range 0.3-1.0 seconds.
Claim 6
Dependent Claim
36 words
A process of contour hardening a gear as in claim 1, wherein said gear has teeth on the inner circumference thereof, and said inductor coil is in close proximity to, and concentric with said inner circumference.
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) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |