Patent EP0212082A1 successfully refreshed from Google Patents.
US3585347A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Quality control in resistance welding
Assignee: Welding Institute England
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Filing: 1969-03-28
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Granted: 1971-06-15
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Expires: 1989-03-28
Abstract
Abstract In a resistance welding process, the rate of displacement of a movable electrode, due to expansion of the heated workpieces between the welding electrodes, is measured in a first part of a welding operation and the current flow is then continued after the said first part for a period which is a function of the result of the measurement.
Inventors
- 👤 James Christopher Needham
- 👤 David Bernard Benton
- 👤 Malcolm Douglas Hannah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:01
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24; B23K11/25; B23K11/252; B23K11/253
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
123 words
A method of controlling a resistance welding cycle, comprising the steps of: bringing together under pressure between the electrodes two workpieces to be joined; establishing a flow of electric current between the electrodes and through the two workpieces to be welded; measuring the duration of a first period required to achieve a given expansion of the workpieces in an initial portion of the welding cycle; timing a second period, starting at the end of the first period, which is a function of the length of the first period, the second period being longer for longer values of the first period and shorter for shorter values of the first period, and switching off the welding current at the end of the second timed period.
Claim 2
Independent Claim
123 words
A method of controlling a resistance welding cycle, comprising the steps of: bringing together under pressure between the electrodes two workpieces to be joined; establishing a flow of electric current between the electrodes and through the two workpieces to be welded; measuring the duration of a first period required to achieve a given expansion of the workpieces in an initial portion of the welding cycle; timing a second period, starting at the end of the first period, which is a function of the length of the first period, the second period being longer for longer values of the first period and shorter for shorter values of the first period, and switching off the welding current at the end of the second timed period.
Claim 3
Dependent Claim
29 words
A method as defined in claim 1, which includes the step of increasing the amplitude of the welding current progressively for at least a part of the welding cycle.
Claim 4
Dependent Claim
33 words
A method as defined in claim 1, which includes the step of increasing the amplitude of the welding current progressively for the remainder of the welding cycle after a predetermined period has elapsed.
Claim 5
Dependent Claim
157 words
Apparatus for controlling a resistance welding process comprising: a pair of electrodes; electric current supply conductors connected to said pair of electrodes to cause a current to flow through workpieces placed between said electrodes; sensing means preset in accordance with a predetermined displacement of the electrodes away from one another, such displacement being due to expansion of the workpieces during the welding process; a time-measuring circuit for measuring the interval required for the sensing means to register the said predetermined displacement during the welding process; a time-defining circuit the operation of which is initiated by the sensing means registering the said predetermined displacement of the electrodes and which is arranged to switch off the welding current at the end of the time period which it defines; and means interconnecting the time-defining circuit and the time-measuring circuit so that the period defined by the time-defining circuit is governed in accordance with the interval measured by the time-measuring circuit.
Claim 6
Dependent Claim
157 words
Apparatus for controlling a resistance welding process comprising: a pair of electrodes; electric current supply conductors connected to said pair of electrodes to cause a current to flow through workpieces placed between said electrodes; sensing means preset in accordance with a predetermined displacement of the electrodes away from one another, such displacement being due to expansion of the workpieces during the welding process; a time-measuring circuit for measuring the interval required for the sensing means to register the said predetermined displacement during the welding process; a time-defining circuit the operation of which is initiated by the sensing means registering the said predetermined displacement of the electrodes and which is arranged to switch off the welding current at the end of the time period which it defines; and means interconnecting the time-defining circuit and the time-measuring circuit so that the period defined by the time-defining circuit is governed in accordance with the interval measured by the time-measuring circuit.
Claim 7
Dependent Claim
41 words
Apparatus as defined in claim 4, in which said time-measuring circuit and said time-defining circuit include a common electrical capacitance, the time-measuring circuit including a charging circuit for said capacitance and the time-defining circuit including a discharging circuit for said capacitance.
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) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |