US4195216A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma welding
Assignee: Rolls Royce PLC
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Filing: 1978-03-13
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Granted: 1980-03-25
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Expires: 1998-03-13
Abstract
Abstract In plasma welding apparatus controls are provided which regulate the rates of increasing and decreasing the welding parameters e.g., welding current, gas flow and wire feed to prevent the formations of craters in the weld at the end of a welding run. Improved welds are formed if the wire feed rate is increased prior to the start of the decrease in welding current but after the gas flow to the plasma arc has begun to decrease.
Inventors
- 👤 Derek J. Beauchamp
- 👤 Donald L. A. Weston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:52
CPC Classifications
B; B23; B23K; B23K10/00; B23K10/02; B23K9/00; B23K9/10; B23K9/1006; B23K9/1012; B23K9/1037
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
48 words
A method of terminating a plasma welding operation comprising the steps of: initiating the conclusion of a welding run to close the keyhole formed during the welding run by the plasma arc piercing the workpiece, and subsequently increasing the rate of feed of filler material to the weld.
Claim 2
Independent Claim
48 words
A method of terminating a plasma welding operation comprising the steps of: initiating the conclusion of a welding run to close the keyhole formed during the welding run by the plasma arc piercing the workpiece, and subsequently increasing the rate of feed of filler material to the weld.
Claim 3
Dependent Claim
61 words
A method of terminating a plasma welding operation according to claim 1 and comprising the further steps of: waiting for a predetermined time following increase of the rate of feed of filler material to the weld and subsequently reducing the rate of feed of filler material to the weld at least to the rate of feed prevailing elsewhere during the weld.
Claim 4
Dependent Claim
34 words
A method of terminating a plasma welding run according to claim 2 and comprising the further step of continuing said reduced rate of feed of filler material to the weld for a predetermined time.
Claim 5
Dependent Claim
23 words
A method according to claim 1 and comprising the further step of reversing the direction of feed of filler material to the weld.
Claim 6
Dependent Claim
30 words
A method according to claim 3 and comprising the further step of reversing the direction of feed of filler material to the weld at the end of said predetermined time.
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) | 1983-03-25 | 1983-09-24 | 1984-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-25 | 1987-09-24 | 1988-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-25 | 1991-09-24 | 1992-03-25 | $7700.00 | Window Closed / Lapsed |