Patent US4042800A successfully refreshed from Google Patents.
US4042800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Welding apparatus
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1976-02-09
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Granted: 1977-08-16
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Expires: 1996-02-09
Abstract
Abstract Apparatus for indicating the time and welding current of a welding cycle is provided, along with means for monitoring the welding current and for preventing further welding cycles if the current is outside certain preset limits. The invention is used with stud welding apparatus in which a stud is placed against a workpiece, then withdrawn, and at the same time a pilot arc is formed; subsequently, a main welding arc is established which forms pools of molten metal on the stud and on the workpiece, the metal solidifying when the stud is subsequently plunged against the workpiece, thereby completing the weld. The length of time of the welding cycle and the welding current flowing during the existence of the main welding arc have, of course, heretofore been measured under laboratory conditions. However, such has not been accomplished under field conditions with commercial stud welding apparatus and particularly where such is accomplished by measuring both the welding time and welding current on a single meter. In a preferred form, the time and current values are stored through the use of relatively low-cost capacitors to make the invention even more practical. In addition, the average weld current is sensed after the weld is complete and further welds can be prevented if this current is not within certain limits.
Inventors
- 👤 Paul A. Glorioso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:28
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/20; B23K9/201
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
192 words
Apparatus for end welding a stud to a workpiece comprising means for holding a stud, an electrically operated retraction coil for retracting the stud-holding means away from the workpiece, means including a conductor for supplying electrical power to said retraction coil, current means including a conductor for supplying welding current to said stud-holding means, a shunt associated with said current means for effecting an electrical signal responsive to the magnitude of the welding current, a first capacitor, means responsive to the signal for charging said first capacitor, a second capacitor, a constant source of current for charging said second capacitor, means associated with one of said conductors for connecting said shunt to said first capacitor and for connecting said constant source of current to said second capacitor while current is flowing through the associated conductor, a meter, means for selectively connecting said first capacitor and said second capacitor to said meter, means for preventing an additional weld cycle if the welding current for the previous cycle was below a predetermined minimum, and means for preventing an additional weld cycle if the welding current for the previous cycle was above a predetermined maximum.
Claim 2
Dependent Claim
192 words
Apparatus for end welding a stud to a workpiece comprising means for holding a stud, an electrically operated retraction coil for retracting the stud-holding means away from the workpiece, means including a conductor for supplying electrical power to said retraction coil, current means including a conductor for supplying welding current to said stud-holding means, a shunt associated with said current means for effecting an electrical signal responsive to the magnitude of the welding current, a first capacitor, means responsive to the signal for charging said first capacitor, a second capacitor, a constant source of current for charging said second capacitor, means associated with one of said conductors for connecting said shunt to said first capacitor and for connecting said constant source of current to said second capacitor while current is flowing through the associated conductor, a meter, means for selectively connecting said first capacitor and said second capacitor to said meter, means for preventing an additional weld cycle if the welding current for the previous cycle was below a predetermined minimum, and means for preventing an additional weld cycle if the welding current for the previous cycle was above a predetermined maximum.
Claim 3
Dependent Claim
27 words
Apparatus according to claim 1 characterized by said means associated with one of said conductors comprises a relay connected in parallel with said electrically operated retraction coil.
Claim 4
Dependent Claim
50 words
Apparatus according to claim 1 characterized by a third capacitor connected to said constant source of current for being charged by same, and means for discharging said third capacitor at the end of the weld cycle and for discharging said second capacitor at the beginning of the next weld cycle.
Claim 5
Dependent Claim
216 words
Apparatus for end welding a stud to a workpiece comprising means for holding a stud, electrically operated means for retracting the stud-holding means away from the workpiece, means including a conductor for supplying electrical power to said retracting means, current means including a conductor for supplying welding current to said stud-holding means, a shunt connected with said current means conductor for effecting an electrical signal responsive to the magnitude of the welding current, a first capacitor, an operational amplifier for charging said first capacitor in response to the signal from said shunt, a second capacitor, a constant source of current for charging said second capacitor, means associated with one of said conductors for connecting said shunt to said first capacitor and for connecting said constant source of current to said second capacitor while current is flowing through the associated conductor, a meter, manually operated means for selectively connecting said first capacitor and said second capacitor to said meter to provide a visual indication of the average weld current and the time of the weld cycle, means for preventing an additional weld cycle if the welding current for the previous cycle was below a predetermined minimum, and means for preventing an additional weld cycle if the weld current for the previous cycle was above a predetermined maximum.
Claim 6
Dependent Claim
216 words
Apparatus for end welding a stud to a workpiece comprising means for holding a stud, electrically operated means for retracting the stud-holding means away from the workpiece, means including a conductor for supplying electrical power to said retracting means, current means including a conductor for supplying welding current to said stud-holding means, a shunt connected with said current means conductor for effecting an electrical signal responsive to the magnitude of the welding current, a first capacitor, an operational amplifier for charging said first capacitor in response to the signal from said shunt, a second capacitor, a constant source of current for charging said second capacitor, means associated with one of said conductors for connecting said shunt to said first capacitor and for connecting said constant source of current to said second capacitor while current is flowing through the associated conductor, a meter, manually operated means for selectively connecting said first capacitor and said second capacitor to said meter to provide a visual indication of the average weld current and the time of the weld cycle, means for preventing an additional weld cycle if the welding current for the previous cycle was below a predetermined minimum, and means for preventing an additional weld cycle if the weld current for the previous cycle was above a predetermined maximum.
Claim 7
Dependent Claim
246 words
Apparatus for welding a stud to a workpiece comprising means for holding a stud, electrically operated means for retracting the stud-holding means away from the workpieece, power means for supplying electrical power to said electrically operated means, current means for supplying welding current to said stud-holding means, means associated with said current means for effecting an electrical signal responsive to the magnitude of welding current, first means responsive to the signal for producing a first voltage, a constant source of current, second means including a capacitor responsive to said constant source of current for producing a second voltage, the magnitude of which is dependent on the time said constant source of current and said capacitor are connected together, switch means associated with one of said power means and said current means for connecting said first means to said signal means and for connecting said constant source of current to said capacitor while the associated one of said power means and current means is supplying power, a meter, manually operated means for selectively connecting said first means and said capacitor to said meter to provide a visual indication of the average weld current and the time of the weld cycle, an additional capacitor, and means connected in circuit with the first capacitor and said additional capacitor so that one of said capacitors is discharged at the end of a weld cycle and the other of said capacitors is discharged at the beginning of the next weld cycle.
Claim 8
Dependent Claim
246 words
Apparatus for welding a stud to a workpiece comprising means for holding a stud, electrically operated means for retracting the stud-holding means away from the workpieece, power means for supplying electrical power to said electrically operated means, current means for supplying welding current to said stud-holding means, means associated with said current means for effecting an electrical signal responsive to the magnitude of welding current, first means responsive to the signal for producing a first voltage, a constant source of current, second means including a capacitor responsive to said constant source of current for producing a second voltage, the magnitude of which is dependent on the time said constant source of current and said capacitor are connected together, switch means associated with one of said power means and said current means for connecting said first means to said signal means and for connecting said constant source of current to said capacitor while the associated one of said power means and current means is supplying power, a meter, manually operated means for selectively connecting said first means and said capacitor to said meter to provide a visual indication of the average weld current and the time of the weld cycle, an additional capacitor, and means connected in circuit with the first capacitor and said additional capacitor so that one of said capacitors is discharged at the end of a weld cycle and the other of said capacitors is discharged at the beginning of the next weld cycle.
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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) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |