US3774006A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resistance welding control
Assignee: Pressed Steel Fisher Ltd
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Filing: 1971-12-20
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Granted: 1973-11-20
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Expires: 1991-12-20
Abstract
Abstract The time for which welding current, in a resistance welding operation, is allowed to flow is made up of two consecutive parts. The first is that taken by the rate of change of weld resistance to reach a predetermined value. The second is computed as a function of the time for the rate of change to reach said value.
Inventors
- 👤 D Pasquire
- 👤 P Burton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:55
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24; B23K11/25; B23K11/252; B23K11/256; B23K11/241; B23K11/246
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
75 words
In a method of resistance welding in which weld current is passed through a workpiece the steps of a. monitoring the rate of change of weld resistance or a function thereof; and b. allowing welding current to flow for an additional time after the rate of change of weld resistance has reached a predetermined value, said additional time being computed as a function of the time for the rate of change to reach said value.
Claim 2
Dependent Claim
75 words
In a method of resistance welding in which weld current is passed through a workpiece the steps of a. monitoring the rate of change of weld resistance or a function thereof; and b. allowing welding current to flow for an additional time after the rate of change of weld resistance has reached a predetermined value, said additional time being computed as a function of the time for the rate of change to reach said value.
Claim 3
Dependent Claim
33 words
A method of resistance welding as claimed in claim 1 in which the predetermined value of the rate of change of weld resistance is zero and the weld resistance is at a maximum.
Claim 4
Dependent Claim
41 words
A method of resistance welding as claimed in claim 1 in which the addition time is made up of the time to reach the predetermined value multiplied by a predetermined constant the multiple being adjusted by adding a predetermined time value.
Claim 5
Dependent Claim
37 words
A method of resistance welding as claimed in claim 3 in which the predetermined constant is in the range of 0.2 to 3.5 and the predetermined time value is in the range of -100 to +100 milliseconds.
Claim 6
Dependent Claim
20 words
A method of resistance welding as claimed in claim 4 in which the value of the predetermined constant is one.
Claim 7
Dependent Claim
18 words
A method of resistance welding as claimed in claim 4 in which the predetermined time is 40 milliseconds.
Claim 8
Dependent Claim
58 words
A method of resistance welding as claimed in claim 1 in which the time for the rate of change of resistance to reach a predetermined value is derived from a series of signals proportionately related to weld resistanCe and registering the time when successive values of such signals indicate the rate of increase has reached the predetermined value.
Claim 9
Dependent Claim
131 words
A resistance welding controller whereby weld current is allowed to pass through a workpiece characterised by the provision of: a. switch means adapted to allow welding current to flow; b. means for monitoring the workpiece weld resistance or a function related thereto; c. means for detecting when the rate of change of the resistance or the function thereof has reached a predetermined value; d. means for calculating an additional time (Tt) for which welding current is allowed to flow defined by the identity Tt (Tp X A)+ B wherein Tp is the time taken for the rate of change to reach the predetermined value, Tt > or = Tp, and A and B are constants; and e. means for opening the switch means when the time (Tp + Tt) has expired.
Claim 10
Dependent Claim
131 words
A resistance welding controller whereby weld current is allowed to pass through a workpiece characterised by the provision of: a. switch means adapted to allow welding current to flow; b. means for monitoring the workpiece weld resistance or a function related thereto; c. means for detecting when the rate of change of the resistance or the function thereof has reached a predetermined value; d. means for calculating an additional time (Tt) for which welding current is allowed to flow defined by the identity Tt (Tp X A)+ B wherein Tp is the time taken for the rate of change to reach the predetermined value, Tt > or = Tp, and A and B are constants; and e. means for opening the switch means when the time (Tp + Tt) has expired.
Claim 11
Dependent Claim
29 words
A resistance welding controller as claimed in claim 8 characterised in that the predetermined value of the rate of change is zero and the weld resistance is a maximum.
Claim 12
Dependent Claim
24 words
A resistance welding controller as claimed in claim 9 characterised in that the value of A is in the range of 0.2 to 3.5.
Claim 13
Dependent Claim
18 words
A resistance welding controller as claimed in claim 10 characterised in that the value of A is one.
Claim 14
Dependent Claim
25 words
A resistance welding controller as claimed in claim 9 characterised in that the value of B is in the range of -100 to +100 milliseconds.
Claim 15
Dependent Claim
20 words
A resistance welding controller as claimed in claim 12 characterised in that the value of B is about +40 milliseconds.
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) | 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 |