US3774007A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Welding apparatus
Assignee: Hobart Brothers LLC
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Filing: 1972-04-19
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Granted: 1973-11-20
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Expires: 1992-04-19
Abstract
Abstract An improved welding power supply includes saturable reactor means in its output to control welding current. A pulse generator is used to control the firing of SCRs which in turn control the average current in the control winding of the reactor and thus the welding current. A unique current sensing circuit provides a feedback voltage to the pulse generator and monitors alternating current, direct current and direct current-reverse polarity welding current without mechanical switching means. The pulse generator is provided with a secondary control circuit which may be used for a limited time to provide higher initial currents to aid in the establishment of the arc. A secondary power supply is also provided which may be connected in parallel with the main power supply to provide a relatively high open circuit voltage to heat the electrode and establish the arc.
Inventors
- 👤 W Chiasson
- 👤 R Barhorst
- 👤 B Muter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:39
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/10; B23K9/1006; B23K9/1043; B23K9/1056
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
140 words
In a welding power supply, the combination including a primary power source capable of supplying current at a controlled rate to a welding arc established between a tungsten electrode anda workpiece, said power source having a relatively low open circuit voltage; a second power source in parallel with said primary source for spplying to the electrode a relatively high open circuit voltage in order initially to establish an arc; and means for sensing the initiation of an arc between the electrode and the workpiece; the improvement comprising timer means responsive to said sensing means for disconnecting said secondary power source from the primary power source after a predetermined period of time has elapsed since the initiation of an arc sufficient to heat the electrode to sustain the arc thus established at the lower voltage provided by said primary power source.
Claim 2
Dependent Claim
140 words
In a welding power supply, the combination including a primary power source capable of supplying current at a controlled rate to a welding arc established between a tungsten electrode anda workpiece, said power source having a relatively low open circuit voltage; a second power source in parallel with said primary source for spplying to the electrode a relatively high open circuit voltage in order initially to establish an arc; and means for sensing the initiation of an arc between the electrode and the workpiece; the improvement comprising timer means responsive to said sensing means for disconnecting said secondary power source from the primary power source after a predetermined period of time has elapsed since the initiation of an arc sufficient to heat the electrode to sustain the arc thus established at the lower voltage provided by said primary power source.
Claim 3
Dependent Claim
99 words
The welding power supply of claim 1 wherein said sensing means includes a voltage sensing circuit connected across the output of said secondary power source to detect the initiation of a welding arc by a lowering of the output voltage of the secondary power supply, said circuit including a Zener diode; and a relay in series with said Zener diode; said relay being energized while the voltage across said Zener diode is sufficient to cause conduction thereof, said relay becoming deenergized when the voltage output of said secondary power source is lowered due to the initiation of an arc.
Claim 4
Dependent Claim
55 words
The welding power supply of claim 1 further including a third power source connected to the electrode for providing high frequency, high voltage, low current pulses to aid in the establishment of an arc, and means responsive to said sensing means for disconnecting said third power source from said electrode upon initiation of an arc.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |