US5196668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
DC resistance welding apparatus
Assignee: Honda Motor Co Ltd
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Filing: 1992-03-12
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Granted: 1993-03-23
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Expires: 2012-03-12
Abstract
Abstract A DC resistance welding apparatus includes a pair of welding electrodes for sandwiching workpieces to be welded therebetween and a circuit connected to the welding electrodes for supplying a welding current to said welding electrodes. The circuit includes a plurality of parallel-connected rectifying circuits each having a welding transformer and rectifying circuit. The circuit monitors the power signal produced by inverters in the power supply to determine the proper energization time by producing a pulse signal corresponding to the waveform of the power signal. The rise and fall of the pulse signal is then detected and differentiated. The differential signal is used as a basis to control the energization time of the welding gun.
Inventors
- 👤 Nobuo Kobayashi
- 👤 Fumitomo Takano
- 👤 Makoto Suzuki
- 👤 Hitoshi Saito
- 👤 Hidenori Koga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:48
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
178 words
A DC resistance welding apparatus comprising: a welding gun for sandwiching workpieces to be welded therebetween; a power supply unit including, a converter, an inverter, a welding transformer, and a rectifier; said power supply unit supplying a welding current produced from said rectifier to said welding gun; detecting means for producing a pulse signal having a leading edge and a trailing edge, said pulse signal corresponding to an output waveform from said inverter; pulse signal edge detecting means for detecting and holding current signals corresponding to the leading and trailing edges of said pulse signal; control means for producing a control signal to enable said pulse signal edge detecting means; and calculating means for producing a logarithmic signal from said current signals, said logarithmic signal being indicative of a change in a resistance of the workpieces when the welding current flows therethrough, produced by said pulse signal edge detecting means and for applying said logarithmic signal to said control means; said control means controlling a flow of current to said welding gun in response to said logarithmic signal.
Claim 2
Dependent Claim
178 words
A DC resistance welding apparatus comprising: a welding gun for sandwiching workpieces to be welded therebetween; a power supply unit including, a converter, an inverter, a welding transformer, and a rectifier; said power supply unit supplying a welding current produced from said rectifier to said welding gun; detecting means for producing a pulse signal having a leading edge and a trailing edge, said pulse signal corresponding to an output waveform from said inverter; pulse signal edge detecting means for detecting and holding current signals corresponding to the leading and trailing edges of said pulse signal; control means for producing a control signal to enable said pulse signal edge detecting means; and calculating means for producing a logarithmic signal from said current signals, said logarithmic signal being indicative of a change in a resistance of the workpieces when the welding current flows therethrough, produced by said pulse signal edge detecting means and for applying said logarithmic signal to said control means; said control means controlling a flow of current to said welding gun in response to said logarithmic signal.
Claim 3
Dependent Claim
43 words
The DC resistance welding apparatus as claimed in claim 1, wherein said control means further comprises: de-energizing means for disabling said inverter so as to cut off welding current supplied to said welding gun when said logarithmic signal is of a predetermined value.
Claim 4
Dependent Claim
47 words
The DC resistance welding apparatus as claimed in claim 1, wherein said calculating means further comprises: a logarithmic amplifier to produce an analog logarithmic signal defined by log (I/IO) wherein I and IO are current values at the leading and trailing edges of said pulse signal, respectively.
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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) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |