Patent US4031349A successfully refreshed from Google Patents.
US4031349A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stud welding control
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1975-09-19
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Granted: 1977-06-21
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Expires: 1995-09-19
Abstract
Abstract Controls for use in end welding a stud to a workpiece by a drawn-arc technique are set forth. In welding a stud to a workpiece, an end of the stud is placed against the workpiece and is then retracted as a pilot arc is established between the stud and the workpiece. A welding arc is then superimposed on the pilot arc which causes portions of the stud and the workpiece to become molten. These portions join and solidify to securely weld the stud to the workpiece when the stud is plunged back to engage the workpiece. The controls include a timer dial on a control panel of the welding apparatus for setting the length of time of the welding arc, and a current dial on the control panel to set the current of the welding arc. Particularly for the control of the current, a unique circuit enables a desired current to be maintained even though the line voltage and the length of the welding cable vary over a wide range. The controls are accurate enough that the dials for the time and current can be set to recommended settings for a particular size of stud and effective welds will be achieved without any experimentation, assuming the amount of lift and plunge of the tool are also properly set.
Inventors
- 👤 Paul A. Glorioso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:54
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/20; B23K9/201
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
314 words
Apparatus for welding a stud to a workpiece comprising a multi-phase power supply, electrical means for withdrawing the stud from the workpiece when said means is energized, spring means for plunging the stud toward the workpiece when said electrical means is deenergized, means connected with said power supply, the stud, and the workpiece for supplying rectified power from said supply to the stud and the workpiece to establish a pilot arc therebetween, additional means connected with said power supply, the stud, and the workpiece for supplying rectified power to the stud and the workpiece for establishing a main welding arc therebetween, said additional means including a semi-conductor controlled rectifier for each phase of the power supply, phase control means for sequentially causing said semi-conductor controlled rectifiers to conduct at predetermined times relative to the cycles of the multi-phase power supply, said phase control means including independent means for firing each of said semi-conductor controlled rectifiers, and means for energizing said firing means including a shunt in a welding circuit for the welding current, means for receiving a signal from said shunt, and hand-manipulatable means for modulating said signal and for changing the times in the cycles of the power supply at which said firing means are energized, a timing circuit connected to said electrical means to deenergize said electrical means and to enable said spring means to plunge the stud toward the workpiece, hand-manipulatable means for controlling the actuation of said timing circuit to control the time in the welding cycle at which the electrical means is deenergized and the stud is plunged toward the workpiece, said firing means comprising capacitor means effective to cause said semi-conductor controlled rectifiers to conduct when a charge on said capacitor means reaches a given value, circuit means for controlling the charging rate of said capacitor means, and up-slope circuit means for supplying power to said circuit means.
Claim 2
Dependent Claim
314 words
Apparatus for welding a stud to a workpiece comprising a multi-phase power supply, electrical means for withdrawing the stud from the workpiece when said means is energized, spring means for plunging the stud toward the workpiece when said electrical means is deenergized, means connected with said power supply, the stud, and the workpiece for supplying rectified power from said supply to the stud and the workpiece to establish a pilot arc therebetween, additional means connected with said power supply, the stud, and the workpiece for supplying rectified power to the stud and the workpiece for establishing a main welding arc therebetween, said additional means including a semi-conductor controlled rectifier for each phase of the power supply, phase control means for sequentially causing said semi-conductor controlled rectifiers to conduct at predetermined times relative to the cycles of the multi-phase power supply, said phase control means including independent means for firing each of said semi-conductor controlled rectifiers, and means for energizing said firing means including a shunt in a welding circuit for the welding current, means for receiving a signal from said shunt, and hand-manipulatable means for modulating said signal and for changing the times in the cycles of the power supply at which said firing means are energized, a timing circuit connected to said electrical means to deenergize said electrical means and to enable said spring means to plunge the stud toward the workpiece, hand-manipulatable means for controlling the actuation of said timing circuit to control the time in the welding cycle at which the electrical means is deenergized and the stud is plunged toward the workpiece, said firing means comprising capacitor means effective to cause said semi-conductor controlled rectifiers to conduct when a charge on said capacitor means reaches a given value, circuit means for controlling the charging rate of said capacitor means, and up-slope circuit means for supplying power to said circuit means.
Claim 3
Dependent Claim
28 words
Apparatus according to claim 1 characterized by flip-flop circuit means for discharging said capacitor means prior to each half cycle of each phase of the multi-phase power supply.
Claim 4
Dependent Claim
224 words
Apparatus for welding a stud to a workpiece comprising a three-phase power supply, means for establishing a pilot arc between the stud and the workpiece, means including a plurality of semi-conductor controlled rectifiers located in series with said power supply, the stud, and the workpiece for establishing a main welding arc between the stud and the workpiece, phase control means sequentially firing said semi-conductor controlled rectifiers to establish a constant main welding arc current even with fluctuations in the voltage of the three-phase power supply and changes in the resistance of the main welding arc circuit, said phase control means including weld current sensing means producing a signal responsive to the welding current, a circuit for receiving the signal, for comparing the signal with a constant signal and for producing a combined signal, means responsive to the combined signal for firing the semi-conductor controlled rectifiers during the cycles of the power supply in response to the combined signal received from said circuit, said means responsive to the combined signal comprising a capacitor for each phase of said power supply, and a flip-flop circuit for each of said capacitors, each flip-flop circuit discharging the corresponding capacitor prior to each half cycle of the corresponding phase of said three-phase power supply, and a sloped circuit for controlling the signal from said sensing means to said circuit.
Claim 5
Dependent Claim
224 words
Apparatus for welding a stud to a workpiece comprising a three-phase power supply, means for establishing a pilot arc between the stud and the workpiece, means including a plurality of semi-conductor controlled rectifiers located in series with said power supply, the stud, and the workpiece for establishing a main welding arc between the stud and the workpiece, phase control means sequentially firing said semi-conductor controlled rectifiers to establish a constant main welding arc current even with fluctuations in the voltage of the three-phase power supply and changes in the resistance of the main welding arc circuit, said phase control means including weld current sensing means producing a signal responsive to the welding current, a circuit for receiving the signal, for comparing the signal with a constant signal and for producing a combined signal, means responsive to the combined signal for firing the semi-conductor controlled rectifiers during the cycles of the power supply in response to the combined signal received from said circuit, said means responsive to the combined signal comprising a capacitor for each phase of said power supply, and a flip-flop circuit for each of said capacitors, each flip-flop circuit discharging the corresponding capacitor prior to each half cycle of the corresponding phase of said three-phase power supply, and a sloped circuit for controlling the signal from said sensing means to said circuit.
Claim 6
Dependent Claim
25 words
Apparatus according to claim 5 characterized by means for discharging an up-slope capacitor of said up-slope circuit when the charge thereon equals the constant signal.
Claim 7
Dependent Claim
233 words
Apparatus for welding a stud to a workpiece comprising a three-phase power supply, means for establishing a pilot arc between the stud and the workpiece, means including a plurality of semi-conductor controlled rectifiers located in series with said power supply, the stud, and the workpiece for establishing a main welding arc between the stud and the workpiece, phase control means sequentially firing said semi-conductor controlled rectifiers to establish a constant main welding arc current even with fluctuations in the voltage of the three-phase power supply and changes in the resistance of the main welding arc circuit, said phase control means including weld current sensing means producing a signal responsive to the welding current, a circuit for receiving the signal, for comparing the signal with a constant signal and for producing a combined signal, means responsive to the combined signal for firing the semi-conductor controlled rectifiers during the cycles of the power supply in response to the conbined signal received from said circuit, said means responsive to the combined signal comprising a capacitor for each phase of said power supply, and a flip-flop circuit for each of said capacitors, each flip-flop circuit discharging the corresponding capacitor prior to each half cycle of the corresponding phase of said three-phase power supply, and an up-slope circuit for supplying increasing voltage to said circuit from the beginning of the weld cycle until the constant signal is reached.
Claim 8
Dependent Claim
233 words
Apparatus for welding a stud to a workpiece comprising a three-phase power supply, means for establishing a pilot arc between the stud and the workpiece, means including a plurality of semi-conductor controlled rectifiers located in series with said power supply, the stud, and the workpiece for establishing a main welding arc between the stud and the workpiece, phase control means sequentially firing said semi-conductor controlled rectifiers to establish a constant main welding arc current even with fluctuations in the voltage of the three-phase power supply and changes in the resistance of the main welding arc circuit, said phase control means including weld current sensing means producing a signal responsive to the welding current, a circuit for receiving the signal, for comparing the signal with a constant signal and for producing a combined signal, means responsive to the combined signal for firing the semi-conductor controlled rectifiers during the cycles of the power supply in response to the conbined signal received from said circuit, said means responsive to the combined signal comprising a capacitor for each phase of said power supply, and a flip-flop circuit for each of said capacitors, each flip-flop circuit discharging the corresponding capacitor prior to each half cycle of the corresponding phase of said three-phase power supply, and an up-slope circuit for supplying increasing voltage to said circuit from the beginning of the weld cycle until the constant signal is reached.
Claim 9
Dependent Claim
289 words
Apparatus for welding a stud to a workpiece comprising a multi-phase current power supply, rectifying and switch means connected with said power supply, the stud, and the workpiece for supplying rectified power between the stud and the workpiece to establish a pilot arc therebetween, additional switch means connected with said power supply, the stud, and the workpiece for supplying rectified power between the stud and the workpiece to establish a main welding arc therebetween with said additional switch means including a semi-conductor controlled rectifier for each phase of the power supply located in series with the power supply, the stud, and the workpiece, and phase control means for sequentially causing said semi-conductor controlled rectifiers to conduct in sequence and at predetermined times relative to the cycles of the multi-phase power supply, said phase control means comprising means for each phase of the power supply for firing the semi-conductor controlled rectifiers, a capacitor connected with each of said firing means, flip-flop transistor means for each of said capacitors for discharging the capacitors prior to each half cycle of the associated phase of the multi-phase current power supply, said firing means comprising a programmable unijunction transistor for each of said semi-conductor controlled rectifiers, said phase control means further including a shunt in a welding circuit which is electrically connected to the stud, means for supplying a voltage signal across said shunt to said capacitors to control the rate of charging thereof, amplifying means between said shunt and said capacitors, capacitor means for controlling the output of said amplifying means, said amplifying means comprising a circuit capable of producing an output voltage, an up-slope capacitor for supplying voltage to said circuit, and means for connecting said up-slope passage to said power supply.
Claim 10
Dependent Claim
289 words
Apparatus for welding a stud to a workpiece comprising a multi-phase current power supply, rectifying and switch means connected with said power supply, the stud, and the workpiece for supplying rectified power between the stud and the workpiece to establish a pilot arc therebetween, additional switch means connected with said power supply, the stud, and the workpiece for supplying rectified power between the stud and the workpiece to establish a main welding arc therebetween with said additional switch means including a semi-conductor controlled rectifier for each phase of the power supply located in series with the power supply, the stud, and the workpiece, and phase control means for sequentially causing said semi-conductor controlled rectifiers to conduct in sequence and at predetermined times relative to the cycles of the multi-phase power supply, said phase control means comprising means for each phase of the power supply for firing the semi-conductor controlled rectifiers, a capacitor connected with each of said firing means, flip-flop transistor means for each of said capacitors for discharging the capacitors prior to each half cycle of the associated phase of the multi-phase current power supply, said firing means comprising a programmable unijunction transistor for each of said semi-conductor controlled rectifiers, said phase control means further including a shunt in a welding circuit which is electrically connected to the stud, means for supplying a voltage signal across said shunt to said capacitors to control the rate of charging thereof, amplifying means between said shunt and said capacitors, capacitor means for controlling the output of said amplifying means, said amplifying means comprising a circuit capable of producing an output voltage, an up-slope capacitor for supplying voltage to said circuit, and means for connecting said up-slope passage to said power supply.
Claim 11
Dependent Claim
31 words
Apparatus according to claim 6 characterized by means for disconnecting said up-slope capacitor from said power supply when the voltage on said up-slope capacitor equals the output voltage of said circuit.
Claim 12
Dependent Claim
37 words
Apparatus according to claim 7 characterized by said disconnecting means comprising an additional programmable unijunction transistor connected with said up-slope capacitor which causes said up-slope capacitor to discharge when said additional programmable unijunction transistor is turned on.
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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) | 1980-06-20 | 1980-12-20 | 1981-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-20 | 1984-12-20 | 1985-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-20 | 1988-12-20 | 1989-06-21 | $7700.00 | Window Closed / Lapsed |