US3832518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Welding control apparatus
Assignee: MRT ACQUISITION Corp A DELAWARE CORP
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Filing: 1970-07-24
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Granted: 1974-08-27
•
Expires: 1990-07-24
Abstract
Abstract A firing control system for controlling controllable rectifier devices to control the transfer of energy from a source of energy to a workpiece to be welded and for establishing controlled firing sequences and times.
Inventors
- 👤 Neal G O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:40
CPC Classifications
B; B23; B23K; B23K11/00; B23K11/24; B23K11/248
Claims Analysis
Total Claims: 127
Claim 1
Independent Claim
256 words
A control circuit for an electrical welding system having a source of alternating voltage and current half-cycles connected to an inductive welding load, the welding system including backto-back connected controllable devices each of which conducts when actuated if the voltage applied there-across is of adequate amplitude and correct polarity and continues to conduct, once actuated, until the current therethrough and through the load drops below a certain value, the current through said devices and through the load lagging the voltage of the source while the voltage across said devices cannot change to the instantaneous source voltage value until the conductive one of the devices becomes nonconductive, the control circuit comprising heat control circuit means connected to the controllable devices including selectably variable means for applying a firing signal to the devices for actuating the controllable devices for the remainder of a selectable portion of the alternating current half-cycles to select a percent heat to be fed to the load, sensing transformer means connected to sense the conductive condition of the devices including means for producing a signal which changes with changes in the conductive condition of the devices, and control means connected to said heat control circuit means and the transformer means for inhibiting the actuation of the devices by the heat control means during appropriate of the alternate half-cycles of the alternating voltage source prior to said sensed condition, and removing said inhibiting of the actuation in response to the occurrence of said second condition at the time of or subsequent to said sensed condition.
Claim 2
Dependent Claim
256 words
A control circuit for an electrical welding system having a source of alternating voltage and current half-cycles connected to an inductive welding load, the welding system including backto-back connected controllable devices each of which conducts when actuated if the voltage applied there-across is of adequate amplitude and correct polarity and continues to conduct, once actuated, until the current therethrough and through the load drops below a certain value, the current through said devices and through the load lagging the voltage of the source while the voltage across said devices cannot change to the instantaneous source voltage value until the conductive one of the devices becomes nonconductive, the control circuit comprising heat control circuit means connected to the controllable devices including selectably variable means for applying a firing signal to the devices for actuating the controllable devices for the remainder of a selectable portion of the alternating current half-cycles to select a percent heat to be fed to the load, sensing transformer means connected to sense the conductive condition of the devices including means for producing a signal which changes with changes in the conductive condition of the devices, and control means connected to said heat control circuit means and the transformer means for inhibiting the actuation of the devices by the heat control means during appropriate of the alternate half-cycles of the alternating voltage source prior to said sensed condition, and removing said inhibiting of the actuation in response to the occurrence of said second condition at the time of or subsequent to said sensed condition.
Claim 3
Dependent Claim
17 words
The control circuit according to claim 1 wherein said conductive condition is the voltage across the devices.
Claim 4
Dependent Claim
22 words
A control circuit according to claim 2, wherein said sensing transformer means has a primary winding connected in parallel with said devices.
Claim 5
Dependent Claim
34 words
A control circuit according to claim 1, wherein said sensing transformer means transmits said signal each time that a conductive one of the devices becomes non-conductive, said control means being responsive to said signal.
Claim 6
Dependent Claim
41 words
A control circuit according to claim 4, wherein said control means actuates said devices by applying a pulse of electrical energy thereto, said control to disable the transmission of the said pulse until said signal is received from said sensing means.
Claim 7
Dependent Claim
66 words
A control circuit according to claim 5 wherein said control means includes for each of said controllable devices a solid state firing device, a direct current power supply connected to said firing device for supplying electrical energy to said firing device, and firing device enabling means connected to said firing device and said sensing transformer means for enabling said firing devices in response to said signal.
Claim 8
Dependent Claim
13 words
A control circuit according to claim 1 wherein said controllable devices are ignitrons.
Claim 9
Dependent Claim
46 words
A circuit according to claim 6 wherein each firing device includes energy storing means connected to said direct current supply for storing energy from said direct current power supply and discharging this energy as said applied pulse of electrical energy to one of said controllable devices.
Claim 10
Dependent Claim
83 words
A circuit according to claim 8 further including means for generating a weld condition signal, means responsive to the weld condition signal indicative that the welding system is prepared to weld and wherein the energy storing means is a capacitor which charges during the first cycle of the alternating current following operation of said weld condition signal generating means and discharges for the first time during the second cycle of the alternating current Following the operation of said weld condition signal generating means.
Claim 11
Dependent Claim
93 words
The control circuit of claim 1 further including separate-excitation firing circuit means connected to the devices for applying said input signal to said devices in controlled phase relation to the source, the application of said input signal actuating said devices and adapted to apply controlled portions of the current half-waves to said welding load, and control means connected to said firing circuit means and a corresponding pair of said terminals, said control means being connected to enable said firing circuit means in response to the voltage between said corresponding pair of said terminals.
Claim 12
Dependent Claim
10 words
Circuit according to claim 10 wherein said devices are ignitrons.
Claim 13
Dependent Claim
66 words
Circuit according to claim 11 wherein said firing circuit means comprises a source of energy, said controllable devices including unidirectional current conducting devices having an input circuit, said firing circuit means being connected to the input circuit of the unidirectional devices and effective when actuated for applying a pulse of energy from said source of energy to the input circuit of the unidirectional current conducting devices.
Claim 14
Dependent Claim
36 words
Circuit according to claim 12 wherein said firing circuit further includes energy storing means for storing energy from said last named source of energy and discharging this energy as said applied pulse to said input circuit.
Claim 15
Dependent Claim
70 words
Circuit according to claim 13 further including signal responsive means connected to the said energy storing means, the charging of said energy storing means being controlled by said signal responsive means, means for generating a weld condition signal, and means connected to the weld condition signal generating means and the signal responsive means and responsive to the weld condition signal for signalling that the welding system is prepared to weld.
Claim 16
Dependent Claim
72 words
Circuit according to claim 14 wherein said source of energy further includes a transformer connected between the source of alternating current and the load, and a rectifying means connected between said transformer and said energy storing means, said signal responsive means connected to control the energization of the transformer by said alternating current source, said transformer being connected to said rectifying means to supply direct current energy to said energy storing means.
Claim 17
Dependent Claim
54 words
Circuit according to claim 15 wherein the energy storing means includes a capacitor which charges during the first cycle of the alternating current following the operation of said signal responsive means and which discharges for the first time during the second cycle of the alternating current following the operation of said signal responsive means.
Claim 18
Dependent Claim
13 words
Circuit according to claim 16 wherein said controllable devices include solid state devices.
Claim 19
Dependent Claim
36 words
Circuit according to claim 16 further including filter means connected between said energy storing means and said input circuit of the unidirectional current conducting devices for limiting the rate of energy discharge into said input circuit.
Claim 20
Dependent Claim
23 words
Circuit according to claim 18 wherein said filter means includes an inductance connected in the input circuit of the unidirectional current conducting devices.
Claim 21
Dependent Claim
77 words
Circuit according to claim 19 further comprising inhibiting means connected to said actuating means effective for a selectable period following the commencement of each half cycle for inhibiting the operation of said actuating means, and means for generating a weld initiation signal, means responsive to said initiation signal indicative of a weld interval and effective only during the first half cycle of the alternating current thereafter for inhibiting operation of said actuating means for a preselected period.
Claim 22
Dependent Claim
30 words
Circuit according to claim 20 wherein the inhibiting means includes means for inhibiting operation of said actuating means until the voltage applied to the unidirectional current conducting devices has reversed.
Claim 23
Dependent Claim
31 words
Circuit according tO claim 23 wherein the inhibiting means is operated in synchronism with the source of alternating voltage for alternately inhibiting said actuating means to actuate the associated controllable means.
Claim 24
Dependent Claim
188 words
In a welding system having a source of alternating voltage and a load having a power factor, a resistance welding control system including connecting means for selectively connecting the load to the source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said system including a sensing means connected to the load for sensing the power factor of the load, and a heat control means connected to the sensing means and the connecting means, said heat control means including a timing curve generating means controlled by the sensing means for controlling the connection of the load to the source, said curve generating means generating a curve having a slope characteristic and including means for selectably varying said slope characteristic, said variable slope characteristic varying the selectably variable percent heat, said sensing means initiating the generation of the preselectable slope timing curve by the generating means and cooperating with said curve generating means for correcting for the power factor of the load in selecting the percent heat fed to the load.
Claim 25
Dependent Claim
188 words
In a welding system having a source of alternating voltage and a load having a power factor, a resistance welding control system including connecting means for selectively connecting the load to the source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said system including a sensing means connected to the load for sensing the power factor of the load, and a heat control means connected to the sensing means and the connecting means, said heat control means including a timing curve generating means controlled by the sensing means for controlling the connection of the load to the source, said curve generating means generating a curve having a slope characteristic and including means for selectably varying said slope characteristic, said variable slope characteristic varying the selectably variable percent heat, said sensing means initiating the generation of the preselectable slope timing curve by the generating means and cooperating with said curve generating means for correcting for the power factor of the load in selecting the percent heat fed to the load.
Claim 26
Dependent Claim
69 words
A resistance welding control system according to claim 23, wherein said control system is connected to the connecting means to connect the load to the source during each of a succession of half-cycles of the source, said sensing means including means for connecting the sensing means to the load to sense the power factor of the load during each of a plurality of the half-cycles during a single weld.
Claim 27
Dependent Claim
27 words
A resistance welding control system according to claim 23, wherein the sensing means includes means to produce a signal indicative of the power factor of the load.
Claim 28
Dependent Claim
64 words
A resistance welding control system according to claim 25 wherein said control system is connected to the connecting means to connect the load to the source during each of a succession of the half-cycles of the source, and said sensing means produces a signal indicative of the power factor of the load during each of a plurality of said half-cycles during a single weld.
Claim 29
Dependent Claim
27 words
A resistance welding control system according to claim 25 wherein the power factor signal is indicative of the termination of the flow of current through the load.
Claim 30
Dependent Claim
61 words
A resistance welding control system according to claim 27 wherein the connecting means includes one or more controlled rectifier devices connected between the source of alternating voltage and the load, said heat control means being connected to said controlled rectifier devices to control the conduction of said devices, said sensing means sensing the voltage across the devices for producing said signal.
Claim 31
Dependent Claim
52 words
A resistance welding control system according to claim 28 wherein said controlled rectifier devices are rendered conductive and non-conductive in periodic relation with said source of alternating voltage and said characteristic of the said signal indicative of the power factor of the load being transmitted when said controlled rectifier devices become non-conductive.
Claim 32
Dependent Claim
30 words
A resistance welding control system according to claim 29 wherein said one or more controlled rectifier devices are a pair of back-to-back connected controlled rectifier devices which are alternately conductive.
Claim 33
Dependent Claim
56 words
A resistance welding control system according to claim 30 wherein said controlled rectifier devices are rendered conductive during alternate half-cycles of the source of alternating voltage with each becoming non-conductive before the other becomes conductive, said signal indicative of the power factor of the load being transmitted when either of the controlled rectifier devices becomes non-conductive.
Claim 34
Dependent Claim
26 words
A resistance welding control system according to claim 31 wherein the heat control mEans actuates the rectifier devices during opposite half-cycles of the alternating voltage source.
Claim 35
Dependent Claim
64 words
A resistance welding control system according to claim 32 wherein the welding load has an inductive reactance and the current through the devices and the load lags the source voltage, said heat control means actuating the devices during alternating half-cycles of the alternating voltage source at points in those half-cycles determined by the slope characteristic and the initiating of generation of the timing curve.
Claim 36
Dependent Claim
78 words
A resistance welding control system according to claim 23 wherein the controllable rectifier devices conduct when actuated and continues to conduct until the current therethrough and through the load drops below a certain value, said devices having a characteristic in which the voltage across the devices cannot change to the instant source voltage value until the conductive one of the rectifier devices becomes non-conductive and in which the sensing means detects the change in voltage across the devices.
Claim 37
Dependent Claim
20 words
A resistance welding control system according to claim 34 wherein the sensing means includes a transformer connected across the devices.
Claim 38
Dependent Claim
58 words
A resistance welding control system according to claim 35 wherein the transformer produces a signal which changes with changes of the voltage across the devices, and the heat control means is controlled by the transformer for actuating the rectifier devices during the half-cycles of the alternating voltage source which permit forward conduction of one of the rectifier devices.
Claim 39
Dependent Claim
49 words
A resistance welding control system according to claim 36 wherein the transformer has a primary winding connected across the devices, the transformer being connected to transmit a preselected signal each time that a conductive one of the devices becomes non-conductive, said control means being responsive to the preselected signal.
Claim 40
Dependent Claim
49 words
A resistance welding control system according to claim 37 wherein said control means includes means for actuating the devices by applying a pulse of electrical energy thereto, and in which the control means is disabled to transmit the pulse until the preselected signal is received from the sensing means.
Claim 41
Dependent Claim
79 words
A resistance welding control system according to claim 38 wherein the control means includes a capacitor and a capacitor discharge firing circuit, said capacitor being charged from said source during one half-cycle of the source voltage and being selectively discharged through said capacitor discharge circuit to produce actuation of one of the devices during the next half-cycle of the source voltage, and further including means for preventing discharge of the capacitor until the sensing means produces said preselected signal.
Claim 42
Dependent Claim
67 words
A resistance welding control system according to claim 39 wherein the control means includes timing means for delaying the actuation of the devices for a selected interval following the initiation of timing, said control means includes means connected to said capacitor and said curve generating means for preventing said capacitor from discharging even after the selected interval unless the sensing means has detected the preselected voltage change.
Claim 43
Dependent Claim
74 words
A resistance welding control system according to claim 23 wherein said heat control further includes means connected to said curve generating means for producing a signal having a fixed level, and means connected to said curve generating means and said fixed level producing means for comparing the magnitude of the curve to said fixed level and generating an output signal when the magnitude of said curve bears a preselected relationship to said fixed level.
Claim 44
Dependent Claim
56 words
A resistance welding control system according to claim 41 wherein said heat control means includes means connected to the source for sensing the polarity of selected half-cycles of the alternating voltage and generating a signal indicative of the attainment of the selected relationship between the timing curve and the said reference level and a preselecteD polarity.
Claim 45
Dependent Claim
33 words
A resistance welding control system according to claim 42 further including means connected to said connecting means for feeding said last-named signal to said connecting means to connect the load to the source.
Claim 46
Dependent Claim
50 words
A resistance welding control system according to claim 43 wherein said last-named signal is a firing pulse for causing conduction of said controlled devices connected between the source and the load so that the load is supplied with a preselected portion of the alternating voltage indicative of the percent heat.
Claim 47
Dependent Claim
229 words
In an electrical welding system having a source of alternating voltage and current half-cycles connected to an inductive welding load, the welding system including a pair of back-to-back connected controllable devices each of which conducts when actuated if the voltage applied there-across is of adequate amplitude and correct polarity and continues to conduct, once actuated, until the current therethrough and through the load drops below a certain value, the current through said devices and through the load lagging the voltage of the source while the voltage across said devices cannot change to the instantaneous source voltage value until the conductive one of the devices becomes non-conductive, the method of controlling the system including the steps of applying a firing signal to the devices which is variable in time relative to the current half-cycles for actuating the controllable devices for the remainder of a selectable portion of the alternating current half-cycles to select a precent heat to be fed to the load, sensing the conductive condition of the devices, producing a control signal which changes with changes in the conductive condition of the devices, inhibiting the actuation of the devices during appropriate alternate half-cycles of the alternating voltage source prior to the sensed condition, and removing said inhibiting of the actuation in response to the occurrence of said sensed condition at the time of or subsequent to said sensed condition.
Claim 48
Dependent Claim
229 words
In an electrical welding system having a source of alternating voltage and current half-cycles connected to an inductive welding load, the welding system including a pair of back-to-back connected controllable devices each of which conducts when actuated if the voltage applied there-across is of adequate amplitude and correct polarity and continues to conduct, once actuated, until the current therethrough and through the load drops below a certain value, the current through said devices and through the load lagging the voltage of the source while the voltage across said devices cannot change to the instantaneous source voltage value until the conductive one of the devices becomes non-conductive, the method of controlling the system including the steps of applying a firing signal to the devices which is variable in time relative to the current half-cycles for actuating the controllable devices for the remainder of a selectable portion of the alternating current half-cycles to select a precent heat to be fed to the load, sensing the conductive condition of the devices, producing a control signal which changes with changes in the conductive condition of the devices, inhibiting the actuation of the devices during appropriate alternate half-cycles of the alternating voltage source prior to the sensed condition, and removing said inhibiting of the actuation in response to the occurrence of said sensed condition at the time of or subsequent to said sensed condition.
Claim 49
Dependent Claim
16 words
A method according to claim 45 wherein said conductive condition is the voltage across the devices.
Claim 50
Dependent Claim
52 words
A method according to claim 46 wherein said system includes a sensing transformer means having a primary winding connected in parallel with said devices, wherein the step of producing the control signal includes transmitting the control signal from the transformer means each time that a conductive one of the devices becomes non-conductive.
Claim 51
Dependent Claim
38 words
A method according to claim 47 wherein the step of actuating said devices includes applying a pulse of electrical energy thereto and disabling the transmission of said pulse until said control signal is received from said sensing means.
Claim 52
Dependent Claim
141 words
In a resistance welding system for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, a method of controlling the welding system comprising the steps of sensing the power factor of the load, controlling the connection of the load to the source by generating a curve signal having a selectably variable slope characteristic, varying the slope characteristic of the curve for selecting the desired percent heat, sensing when the curve reaches a preselected magnitude, connecting the source to the load when the magnitude reaches the preselected magnitude, and initiating the generation of the variable slope curve in response to the sensed power factor for correcting for the power factor of the load.
Claim 53
Dependent Claim
141 words
In a resistance welding system for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, a method of controlling the welding system comprising the steps of sensing the power factor of the load, controlling the connection of the load to the source by generating a curve signal having a selectably variable slope characteristic, varying the slope characteristic of the curve for selecting the desired percent heat, sensing when the curve reaches a preselected magnitude, connecting the source to the load when the magnitude reaches the preselected magnitude, and initiating the generation of the variable slope curve in response to the sensed power factor for correcting for the power factor of the load.
Claim 54
Dependent Claim
44 words
A method according to claim 49 further including connecting the load to the source during each of a succession of half-cycles of the source and sensing the power factor of the load during each of a plurality of the half-cycles during a single weld.
Claim 55
Dependent Claim
40 words
A method according to claim 50 further including producing a control signal indicative of the power factor of the load, and wherein the step of initiatinG the generation of the variable slope curve is in response to the control signal.
Claim 56
Dependent Claim
23 words
A method according to claim 51 wherein the control signal is indicative of the termination of the flow of current through the load.
Claim 57
Dependent Claim
18 words
A method according to claim 51 wherein the control signal is indicative of the voltage across the device.
Claim 58
Dependent Claim
75 words
A method according to claim 53 wherein the welding system includes controlled rectifier devices connected between the source and the load, the step of controlling the connection includes selectively actuating the controllable rectifier devices a selectable interval after initiation of generation of the curve signal, the duration of said selectable interval determining the percent heat fed to the load, and controlling the initiation of generation of the curve signal in response to the control signal.
Claim 59
Dependent Claim
97 words
A method according to claim 54 wherein the controllable rectifier devices conduct when actuated and continue to conduct until the current therethrough and through the load drops below a certain value, in which the voltage across the devices cannot change to the instant source voltage value until the conductive one of the rectifier devices becomes non-conductive and in which the signal indicates the change in voltage across the devices, the method further including actuating the devices by applying a pulse of eletrical energy thereto, and disabling the transmission of the pulse until the control signal is received.
Claim 60
Dependent Claim
26 words
A method according to claim 55 further including delaying actuation of the devices for a selectable period following the initiation of generation of the curve signal.
Claim 61
Dependent Claim
53 words
A method according to claim 49 further including the steps of comparing the magnitude of the curve signal to a fixed level, generating an output signal when said curve signal bears a preselected relationship to said fixed level, and applying said output signal to connect the source of alternating voltage to the load.
Claim 62
Dependent Claim
49 words
A method according to claim 57 further including the steps of sensing the polarity of selected half-cycles of the alternating voltage and generating a signal indicative of the attainment of the selected relationship between the magnitude of the curve signal and the said fixed level and a preselected polarity.
Claim 63
Dependent Claim
212 words
A resistance welding control system including connecting means for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the halfcycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said alternating voltage having a characteristic that the current through the load lags the voltage and passes through a zero current point a period of time following the passage through zero of the voltage, said period of time defining the power factor of the load, said system including a sensing means for sensing the power factor of the load, and a heat control means connected to the sensing means and the connecting means including a timing curve generating means controlled by the sensing means for controlling the connecting means and, thus, the connection of the load to the source, said curve generating means generating a curve having a first portion and a second portion, said sensing means terminating the first portion and initiating the generation of the second portion by the generating means in response to the sensed power factor, and means connected to the curve generating means for altering a characteristic of said second portion for selecting the percent heat fed to the load.
Claim 64
Dependent Claim
212 words
A resistance welding control system including connecting means for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the halfcycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said alternating voltage having a characteristic that the current through the load lags the voltage and passes through a zero current point a period of time following the passage through zero of the voltage, said period of time defining the power factor of the load, said system including a sensing means for sensing the power factor of the load, and a heat control means connected to the sensing means and the connecting means including a timing curve generating means controlled by the sensing means for controlling the connecting means and, thus, the connection of the load to the source, said curve generating means generating a curve having a first portion and a second portion, said sensing means terminating the first portion and initiating the generation of the second portion by the generating means in response to the sensed power factor, and means connected to the curve generating means for altering a characteristic of said second portion for selecting the percent heat fed to the load.
Claim 65
Dependent Claim
56 words
A resistance welding control system according to claim 59 including means for connecting the load to the source during each of a succession of half-cycles of the source and in which the sensing means includes means for sensing the power factor of the load during each of a plurality of the half-cycles during a single weld.
Claim 66
Dependent Claim
39 words
A resistance welding control system according to claim 59 wherein the sensing means includes means for produciNg a signal indicative of the power factor of the load, and in which the heat control means is responsive to the signal.
Claim 67
Dependent Claim
44 words
A resistance welding control system according to claim 59 wherein the certain of half-cycles includes half-cycles of both polarities and said second portion characteristic is a selectably variable slope curve and said selecting means includes means for varying the slope of said second portion.
Claim 68
Dependent Claim
60 words
A resistance welding control system according to claim 62 wherein the connecting means includes a controlled rectifier means connected to the heat control means and is controlled by the heat control means, and in which the sensing means senses the voltage across the device and the signal is indicative of the termination of the flow of current through the load.
Claim 69
Dependent Claim
53 words
A resistance welding control system according to claim 63 wherein the controlled rectifier means is rendered conductive and non-conductive in periodic relation with the source, and furhter including means for transmitting the signal indicative of the power factor of the load to said heat control means when the controlled rectifier device becomes non-conductive.
Claim 70
Dependent Claim
74 words
A resistance welding control system according to claim 64 wherein the controlled rectifier means includes a pair of back-to-back connected controlled rectifier devices which are alternately conductive, said controlled rectifier devices being rendered conductive during alternate half-cycles of the source voltage with each becoming non-conductive before the other becomes conductive, and in which the signal indicative of the power factor of the load is transmitted when either of the controlled rectifier devices becomes non-conductive.
Claim 71
Dependent Claim
20 words
A resistance welding control system according to claim 65 wherein the sensing means includes a transformer connected across the devices.
Claim 72
Dependent Claim
51 words
A resistance welding control system according to claim 66 wherein the sensing transformer produces the signal, which signal changes with changes of the voltage across the devices, and the control means is controlled by the sensing transformer for actuating the rectifier devices during appropriate alternate half-cycles of the alternating voltage source.
Claim 73
Dependent Claim
36 words
A resistance welding control system according to claim 67 wberein the transformer has a primary winding connected across the devices, the transformer transmitting the signal each time that a conductive one of the devices becomes non-conductive.
Claim 74
Dependent Claim
47 words
A resistance welding control system according to claim 68 wherein control means actuates the devices by applying a pulse of electrical energy thereto, and in which the control means includes means for disabling the transmission of the pulse until the signal is received from the sensing means.
Claim 75
Dependent Claim
30 words
A resistance welding control system according to claim 69 wherein the control means includes timing means for delaying actuation of the devices in the first cycle for a selectable period.
Claim 76
Dependent Claim
86 words
A resistance welding control system according to claim 70 wherein the control means includes a capacitor, a capacitor charging circuit in which the capacitor is charged during one-half-cycle of the source voltage and a capacitor discharging circuit in which the capacitor is selectively discharged to produce actuation of one of the devices during the next half-cycle of the source voltage, and further including means connected to the discharge circuit for preventing discharge of the capacitor until the sensing means detects the voltage change across the devices.
Claim 77
Dependent Claim
46 words
A resistance welding control system according to claim 59 wherein the heat control means includes means for comparing the magnitude of the curve to a fixed level and generating an output signal when the magnitude of said curve bears a preselected relationship to said fixed level.
Claim 78
Dependent Claim
52 words
A resistance welding control system according to claim 72 wherein said heat control means includes means for sending the polairty of selected half-cycles of the alternating voltage and generating a signal indicative of the attainment of a selected relationship between the timing curve and the said fixed level and a preselected polarity.
Claim 79
Dependent Claim
33 words
A resistance welding control system according to claim 73 further including means connected to said connecting means for feeding said last-named signal to said connecting means for connecting the load to the source.
Claim 80
Dependent Claim
50 words
A resistance welding control system according to claim 74 wherein said last-named signal is a firing pulse for causing conduction of said connecting means connected between the source and the load so that the load is supplied with a preselected portion of the alternating voltage indicative of the percent heat.
Claim 81
Dependent Claim
30 words
A resistance welding control system according to claim 59 wherein the power factor sensing means includes means for sensing the zero voltage cross-over point and the zero current cross-over point.
Claim 82
Dependent Claim
27 words
A resistance welding control system according to claim 76 wherein said zero current cross-over point sensing means includes means for sensing the voltage across said connection means.
Claim 83
Dependent Claim
45 words
A resistance welding control system according to claim 77 wherein the connection means is rendered conductive and non-conductive in periodic relation with the source and in which the signal indicative of the power factor of the load is transmitted when the connection means becomes non-conductive.
Claim 84
Dependent Claim
26 words
A resistance welding control system according to claim 78 wherein the connection means is a pair of back-to-back connected controlled rectifier devices which are alternately conductive.
Claim 85
Dependent Claim
62 words
A resistance welding control system according to claim 79 wherein the controlled rectifier devices are rendered conductive during alternate half-cycles of the source voltage with each becoming non-conductive before the other becomes conductive, and including means for transmitting the signal indicative of the power factor of the load to the heat control means when either of the controlled rectifier devices becomes conductive.
Claim 86
Dependent Claim
80 words
A resistance welding control system according to claim 80 wherein the controllable rectifier devices conduct when actuated and continues to conduct until the current therethrough and through the load drops below a certain value, in which the voltage across the devices cannot change to the instant source voltage value until the conductive one of the rectifier devices becomes non-conductive and in which the sensing means includes means connected across the devices to detect the change in voltage across the devices.
Claim 87
Dependent Claim
20 words
A resistance welding control system according to claim 81 wherein the sensing means includes a transformer connected across the devices.
Claim 88
Dependent Claim
32 words
A resistance welding control system according to claim 72 wherein said second portion characteristic is a variable slope curve which is initiated in response to the sensing of the zero current point.
Claim 89
Dependent Claim
66 words
A resistance welding control system according to claim 83 wherein said curve generating means includes first and second RC timing networks including a resistor and capacitor means for said networks, said system including circuit means for providing a source of charging current for said capacitor means, one of said resistor and capacitor means of said timing networks being selectively variable to select the variable slope characteristic.
Claim 90
Dependent Claim
21 words
A resistance welding control system according to claim 84 wherein said first and second RC timing networks includes a common capacitor.
Claim 91
Dependent Claim
29 words
A resistance welding control system according to claim 84 further including bistable switching means for selectively connecting one of said RC timing networks to the source of charging current.
Claim 92
Dependent Claim
59 words
A resistance welding control system according to claim 86 wherein said bistable switching means is connected between said source of charging current and said timing networks and has a first and second state, said switching means being in said first state during the period between the sensing of said zero voltage cross-over point and said zero current crossover point.
Claim 93
Dependent Claim
31 words
A resistance welding control system according to claim 86 wherein said bistable switching means is switched to said second state in response to the sensing of said zero current cross-over point.
Claim 94
Dependent Claim
209 words
In a resistance welding control system including connecting means for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said alternating voltage having a characteristic that the current through the load lags the voltage and passes through a zero current point a period of time following the passage through zero of the voltage, said period of time defining the power factor of the load, said system including a sensing means for sensing the power factor of the load, and a curve generator, the method of controlling the connection of the load to the source including the steps of sensing the power factor of the load, generating a curve having a constant characteristic portion and a seocnd portion, terminating the first portion and initiating the generation of the second portion by the sensing means in response to the sensed power factor, altering a characteristic of said second portion for selecting the percent heat fed to the load, and controlling the connection means in response to the characteristics of said first and second portions to selectively connect the load to the source.
Claim 95
Dependent Claim
209 words
In a resistance welding control system including connecting means for selectively connecting a load having a power factor to a source of alternating voltage during each of at least certain of the half-cycles of the alternating voltage for each weld in accordance with a variably selectable percent heat, said alternating voltage having a characteristic that the current through the load lags the voltage and passes through a zero current point a period of time following the passage through zero of the voltage, said period of time defining the power factor of the load, said system including a sensing means for sensing the power factor of the load, and a curve generator, the method of controlling the connection of the load to the source including the steps of sensing the power factor of the load, generating a curve having a constant characteristic portion and a seocnd portion, terminating the first portion and initiating the generation of the second portion by the sensing means in response to the sensed power factor, altering a characteristic of said second portion for selecting the percent heat fed to the load, and controlling the connection means in response to the characteristics of said first and second portions to selectively connect the load to the source.
Claim 96
Dependent Claim
43 words
A method according to claim 89 including connecting the load to the source during each of a succession of half-cycles of the source and sensing the power factor of the load during each of a plurality of the half-cycles during a single weld.
Claim 97
Dependent Claim
38 words
A method according to claim 89 including producing a signal indicative of the power factor of the load, and in which the step of controlling the connection of the source and the load is responsive to the signal.
Claim 98
Dependent Claim
43 words
A method according to claim 89 wherein the succession of half-cycles includes half-cycles of both polarities and said second portion is a selectably variable slope curve and said altering a characteristic of the second portion step varies the slope of said second portion.
Claim 99
Dependent Claim
22 words
A method according to claim 92 wherein the signal is indicative of the termination of the flow of current through the load.
Claim 100
Dependent Claim
80 words
A method according to claim 93 wherein the connecting means includes controlled rectifier devices which conduct when actuated and continue to conduct until the current therethrough and through the load drops below a certain value, in which the voltage across the devices cannot change to the instant source voltage value until the conductive one of the rectifier devices becomes non-conductive, wherein the step of sensing the power factor of the load includes detecting the change in voltage across the devices.
Claim 101
Dependent Claim
67 words
A method according to claim 94 further including the steps of sensing the polarity of selected half-cycles of the alternating voltage, sensing the magnitude of the curve, comparing the magnitude of the curve to a fixed reference level and said sensed polarity and generating a further signal indicative of the attainment of a selected relationship between the curve and the said reference level and a preselected polarity.
Claim 102
Dependent Claim
34 words
A method according to claim 95 further including feeding said further signal to the connecting means and controlling the connecting means with the further signal to control connection of the load to the source.
Claim 103
Dependent Claim
48 words
A method according to claim 96 wherein said further signal is a firing pulse for causing conduction of the controlled rectifier devices connected between the source and the load so that the load is supplied with a preselected portion of the alternating voltage indicative of the percent heat.
Claim 104
Dependent Claim
25 words
A method according to claim 89 wherein the power factor sensing step includes sensing the zero voltage cross-over point and the zero current cross-over point.
Claim 105
Dependent Claim
45 words
A method according to claim 98 wherein the contRolled rectifier devices are rendered conductive and nonconductive in periodic relation with the source, the method further including transmitting the signal indicative of the power factor of the load when one of the controlled devices becomes non-conductive.
Claim 106
Dependent Claim
23 words
A method according to claim 98 further including initiating said constant characteristic portion in response to the sensing of the zero voltage point.
Claim 107
Dependent Claim
33 words
A method according to claim 100 wherein said second portion has a variable slope, the method further including initiating said variable slope portion in response to the sensing of said zero current point.
Claim 108
Dependent Claim
33 words
A method according to claim 101 further including actuating the controlled devices by applying a pulse of electrical energy thereto, and disabling the transmission of the pulse until the further signal is received.
Claim 109
Dependent Claim
212 words
A resistance welding system including a source of alternating voltage, a welding load and controlled switch means connected between the source and the welding load for controlling the application of the source to the load in accordance with a desired percent heat, said load having reactance so that a power factor angle exists between the load voltage and load current, the improvement comprising a control system connected to the controlled switch means for controlling the conduction of the controlled switch means for controlling the phase angle of the alternating source at which selected halfcycles are applied to the load in response to the power factor angle and the desired percent heat, said control system including sensing means for sensing the zero cross-over point of the load current and producing a sensing signal in response to said sensed zero point, timing circuit means connected to said sensing means for generating a curve having a first and second portion, said first portion being generated prior to the generation of said sensing signal, said second portion being generated in response to the generation of said sensing signal, and firing circuit means connected to said switch means and said timing circuit means for operating said switch means in response to a characteristic of said second portion.
Claim 110
Dependent Claim
212 words
A resistance welding system including a source of alternating voltage, a welding load and controlled switch means connected between the source and the welding load for controlling the application of the source to the load in accordance with a desired percent heat, said load having reactance so that a power factor angle exists between the load voltage and load current, the improvement comprising a control system connected to the controlled switch means for controlling the conduction of the controlled switch means for controlling the phase angle of the alternating source at which selected halfcycles are applied to the load in response to the power factor angle and the desired percent heat, said control system including sensing means for sensing the zero cross-over point of the load current and producing a sensing signal in response to said sensed zero point, timing circuit means connected to said sensing means for generating a curve having a first and second portion, said first portion being generated prior to the generation of said sensing signal, said second portion being generated in response to the generation of said sensing signal, and firing circuit means connected to said switch means and said timing circuit means for operating said switch means in response to a characteristic of said second portion.
Claim 111
Dependent Claim
38 words
The improvement of claim 103 wherein said timing circuit means includes a chargeable device, said timing circuit means including charging circuit means for providing a preliminary charge on said charging device during the period of said first portion.
Claim 112
Dependent Claim
49 words
The improvement of claim 104 wherein said firing circuit means includes means establishing a reference level, said second portion characteristic being the magnitude of said curve, said firing circuit means including means actuating said controlled switch means when said curve magnitude bears a preselected relationship to said reference level.
Claim 113
Dependent Claim
48 words
The improvement of claim 105 wherein said firing circuit means includes comparator means connected to said curve generating means and said reference level producing means, said comparator means sensing the occurrence of said preselected relationship and generating a control signal in response to said occurrence of said relationship.
Claim 114
Dependent Claim
39 words
The improvement of claim 106 wherein said controlled switch means includes a pair of back-to-back connected controlled rectifier devices, said firing circuit means firing one of said controlled rectifier devices in response to the sensing of said preselected relationship.
Claim 115
Dependent Claim
69 words
The improvement of claim 107 wherein said comparator means includes a programmable unijunction transistor having at least first and second electrodes, said first electrodes of said transistor being interconnected with said chargeable device and said second electrode being connected to said reference level producing means for controlling the conduction of said unijunction transistor when signals from said chargeable device and said reference level producing means achieve said preselected relationship.
Claim 116
Dependent Claim
15 words
The improvement of claim 108 further including means for varying said reference level producing mEans.
Claim 117
Dependent Claim
61 words
The improvement of claim 104 wherein said timing circuit means includes first and second charging circuit means connected to said chargeable device for creating said first and second portions, respectively, circuit means connected to said sensing means for switching the energization of said chargeable device from said first charging circuit to said second charging circuit in response to said sensing signal.
Claim 118
Dependent Claim
44 words
The improvement of claim 110 wherein said first charging circuit includes rectifier means to permit current flow therethrough in one direction, the operation of said switching circuit means in response to said sensing signal back-biasing said rectifier means to disable said first charging circuit.
Claim 119
Dependent Claim
17 words
The improvement of claim 111 wherein said switching circuit means includes a pair of interconnected transistor devices.
Claim 120
Dependent Claim
39 words
The improvement of claim 112 wherein said controllable switch means includes controlled rectifier means, said sensing means including a transformer having a winding connected to said controlled rectifier means to sense a conductive condition of said control rectifier means.
Claim 121
Dependent Claim
30 words
The improvement of claim 113 wherein said controlled rectifier means includes a pair of back-to-back connected controlled rectifier devices, said transformer being connected across corresponding electrodes of said rectifier devices.
Claim 122
Dependent Claim
38 words
The improvement of claim 103 wherein said switch means includes controlled rectifier means, said sensing means including a transformer having a winding connected to said controlled rectifier means to sense a conductive condition of said control rectifier means.
Claim 123
Dependent Claim
30 words
The improvement of claim 115 wherein said controlled rectifier means includes a pair of back-to-back connected controlled rectifier devices, said transformer being connected across corresponding electrodes of said rectifier devices.
Claim 124
Dependent Claim
194 words
In a resistance welding system including a source of alternating voltage, a welding load, controlled switch means connected between the source and the welding load for controlling the application of the source to the load in accordance with a desired percent heat, the load having reactance so that a power factor angle exists between the load voltage and load current, and a control system connected to the controllable switch means, a method of controlling the conduction of the controlled switch means for controlling the phase angle of the alternating source at which selected half-cycles are applied to the load by controlling the actuation of the controllable switch means in response to the power factor angle and the desired percent heat comprising the steps of sensing the zero cross-over point of the load current, producing a sensing signal in response to said sensed zero point, generating a curve having a first and second portion, said first portion being generated prior to the generation of said sensing signal, said second portion being generated in response to the generation of said sensing signal, and operating said switch means in response to a characteristic of said second portion.
Claim 125
Dependent Claim
194 words
In a resistance welding system including a source of alternating voltage, a welding load, controlled switch means connected between the source and the welding load for controlling the application of the source to the load in accordance with a desired percent heat, the load having reactance so that a power factor angle exists between the load voltage and load current, and a control system connected to the controllable switch means, a method of controlling the conduction of the controlled switch means for controlling the phase angle of the alternating source at which selected half-cycles are applied to the load by controlling the actuation of the controllable switch means in response to the power factor angle and the desired percent heat comprising the steps of sensing the zero cross-over point of the load current, producing a sensing signal in response to said sensed zero point, generating a curve having a first and second portion, said first portion being generated prior to the generation of said sensing signal, said second portion being generated in response to the generation of said sensing signal, and operating said switch means in response to a characteristic of said second portion.
Claim 126
Dependent Claim
26 words
The method of claim 117 wherein said curve is generated by charging a chargeable device, said first portion providing a preliminary charge on said charging device.
Claim 127
Dependent Claim
42 words
The method of claim 118 further including the steps of establishing a reference level, said second portion characteristic being the magnitude of said curve, and operating said controllable switch means when said curve magnitude bears a preselected relationship to said reference level.
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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) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |