US3569659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resistance welding
Assignee: Individual
•
Filing: 1969-04-07
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Granted: 1971-03-09
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Expires: 1989-04-07
Abstract
Abstract The progress of a resistance welding process is ascertained by reference to the expansion of the workpieces and to avoid the difficulty of accurately detecting the maximum expansion, in the region of which the expansion/time curve is flattened, a sensing device indicates when the expansion has a selected value between 60 percent and 90 percent of the maximum expansion which would result if the current were allowed to continue. The welding current is switched off at this time or a predetermined interval thereafter. Methods of increasing the size of the weld nugget are described, including reinitiating the flow of welding current after the workpieces have contracted to some extent, this further pulse of current being again terminated when the expansion reaches a selected value before the flattened portion of the expansion/time curve.
Inventors
- 👤 David B Benton
- 👤 Richard G Newling
- 👤 Malcolm D Hannah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:00
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24; B23K11/25; B23K11/251; B23K11/002
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
81 words
A method of joining workpieces by resistance welding, including the step of: presetting a sensing device on a welding machine to operate during a weld when the expansion of the workpieces to be welded reaches a value between 60 percent and 90 percent of a predetermined maximum expansion for the workpieces; squeezing the workpieces between a pair of electrodes and passing a welding current between the electrodes; and switching off the welding current in response to operation of the sensing device.
Claim 2
Independent Claim
81 words
A method of joining workpieces by resistance welding, including the step of: presetting a sensing device on a welding machine to operate during a weld when the expansion of the workpieces to be welded reaches a value between 60 percent and 90 percent of a predetermined maximum expansion for the workpieces; squeezing the workpieces between a pair of electrodes and passing a welding current between the electrodes; and switching off the welding current in response to operation of the sensing device.
Claim 3
Dependent Claim
31 words
A method in accordance with claim 1, in which the sensing device is preset to operate at an expansion between 70 percent and 90 percent of the said predetermined maximum expansion.
Claim 4
Dependent Claim
36 words
A method in accordance with claim 1, in which the sensing device is preset to operate when the expansion of the workpieces reaches a value between 75 percent and 85 percent of the predetermined maximum expansion.
Claim 5
Dependent Claim
75 words
A method in accordance with claim 1, further including the step of subsequently reinitiating the flow of welding current when the expansion of the workpieces has been reduced to a predetermined lower value, the welding current thus flowing for at least two pulses to make the weld and being terminated and reinitiated at predetermined higher and lower values of workpiece expansion, the weld being terminated when a predetermined number of current pulses have taken place.
Claim 6
Dependent Claim
68 words
A method in accordance with claim 1, further including the step of subsequently reinitiating the flow of welding current when the expansion of the workpieces has been reduced to a predetermined lower value, the current flow being terminated and reinitiated at the predetermined higher and lower values of workpiece expansion, and finally terminating the weld a predetermined time after the initiation of the first pulse of welding current.
Claim 7
Dependent Claim
48 words
A method in accordance with claim 1, further comprising the steps of timing a predetermined interval, following switching off the welding current and reinitiating at the end of the said interval, the welding current remaining on until the expansion of the workpieces reaches the said value once again.
Claim 8
Dependent Claim
57 words
A method in accordance with claim 1, further comprising the steps of timing a predetermined interval, following switching off the welding current and reinitiating at the end of the said interval, the welding current remaining on until the workpieces have expanded, from their condition at the beginning of the new welding current pulse, through a predetermined amount.
Claim 9
Dependent Claim
29 words
A method in accordance with claim 1, in which the welding current is switched off to terminate the weld a predetermined period after the operation of the sensing device.
Claim 10
Dependent Claim
33 words
A method in accordance with claim 1, in which the electrode tip diameter is at least 1.2 tins. (that is to say 6 t mm.), where t is the thickness of the workpieces.
Claim 11
Dependent Claim
20 words
A method in accordance with claim 1, in which the amplitude of the welding current increases progressively throughout the weld.
Claim 12
Dependent Claim
26 words
A method in accordance with claim 1, in which the amplitude of the welding current increases progressively if the weld cycle continues beyond a predetermined duration.
Claim 13
Dependent Claim
31 words
A method in accordance with claim 1, in which the amplitude of the welding current increases to a higher steady value if the weld has not terminated within a predetermined duration.
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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |