US3708645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of heating a workpiece of particulate material
Assignee: Park Ohio Holdings Corp
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Filing: 1971-10-12
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Granted: 1973-01-02
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Expires: 1991-10-12
Abstract
Abstract A workpiece formed from compacted, electrically conductive particles is heated by first passing a high-frequency current through the workpiece and then by inductively heating the workpiece.
Inventors
- 👤 H Osborn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:56
CPC Classifications
H; H05; H05B; H05B11/00; B; B22; B22F; B22F3/00; B22F3/10; B22F3/105
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
68 words
A method of heating a workpiece formed from compacted, electrically conductive particles to a preselected temperature said method comprising the steps of: passing a current having a frequency of at least about 1,000 cycles per second through said workpiece to heat said workpiece to a temperature causing at least partial fusing of adjacent particles, but substantially below said preselected temperature; and, inductively heating said workpiece to said temperature.
Claim 2
Independent Claim
68 words
A method of heating a workpiece formed from compacted, electrically conductive particles to a preselected temperature said method comprising the steps of: passing a current having a frequency of at least about 1,000 cycles per second through said workpiece to heat said workpiece to a temperature causing at least partial fusing of adjacent particles, but substantially below said preselected temperature; and, inductively heating said workpiece to said temperature.
Claim 3
Dependent Claim
28 words
A method as defined in claim 1, wherein said inductive heating step includes surrounding said workpiece with a multi-turn coil and energizing said coil with an alternating current.
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) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |