Patent US3571552A successfully refreshed from Google Patents.
US3571552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of resistance welding using pulsed dc superimposed over steady state dc voltage
Assignee: POWER CONTROL CORP
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Filing: 1970-02-24
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Granted: 1971-03-23
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Expires: 1990-02-24
Abstract
Abstract Apparatus for welding, particularly resistance seam welding, wherein the voltage applied across the weld comprises a steady state direct current voltage having superimposed thereon an alternating current voltage or a chopped direct current voltage. This provides a true diffusion weld, results in a substantially uniform grain structure across the weld, and enables extremely high welding speeds.
Inventors
- 👤 Kenneth E Opal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:24
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24; B23K11/25; B23K11/252; B23K11/241; B23K11/245
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
Apparatus for welding edges of a metallic workpiece, comprising a source of steady state direct current, means for applying said source of steady state direct current across a pair of resistance welding electrodes between which said edges are positioned, means for producing relative movement between said edges and said electrodes, an inverter for producing a square wave output, rectifier means coupled to said inverter for producing a train of direct current pulses, and means for applying said pulses across said electrodes in parallel with said means for applying said source of steady state direct current.
Claim 2
Dependent Claim
95 words
Apparatus for welding edges of a metallic workpiece, comprising a source of steady state direct current, means for applying said source of steady state direct current across a pair of resistance welding electrodes between which said edges are positioned, means for producing relative movement between said edges and said electrodes, an inverter for producing a square wave output, rectifier means coupled to said inverter for producing a train of direct current pulses, and means for applying said pulses across said electrodes in parallel with said means for applying said source of steady state direct current.
Claim 3
Dependent Claim
21 words
The apparatus of claim 1 wherein said rectifier means comprises a full-wave rectifier incorporating semiconductive controlled rectifiers as unidirectional current devices.
Claim 4
Dependent Claim
25 words
The apparatus of claim 2, including means for varying the points during each cycle of said square wave at which said semiconductive controlled rectifiers fire.
Claim 5
Dependent Claim
14 words
The apparatus of claim 1 including an inductor connecting said rectifier to said electrodes.
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) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |