US3778581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time-at-temperature a-c reflow soldering power supply
Assignee: Raytheon Co
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Filing: 1972-08-03
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Granted: 1973-12-11
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Expires: 1992-08-03
Abstract
Abstract An improved a-c power supply for use in a reflow soldering system is disclosed. The output from a thermocouple attached to the heater bar is amplified and compared to a preset reference voltage. This controls the rate at which a-c current is fed to the heater and thus controls the heater temperature. A timing circuit synchronized to the line frequency is activated when the heater temperature reaches its preset value. A fail-safe shutdown circuit is provided to disable the output should one of the thermocouple leads break. Furthermore, should the heater not reach the desired temperature within a reasonable time, the power is turned off, thereby protecting the circuit elements in the event of a shorted heater or cabling to the heater.
Inventors
- 👤 B Denny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:00
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/22; B; B23; B23K; B23K3/00; B23K3/04; B23K3/047; B23K3/0478
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
120 words
In a reflow soldering system, the combination comprising: a heater bar; a thermocouple attached to said heater bar; reference means for providing a reference output corresponding to a desired heater bar temperature; comparison means for comparing the output from said thermocouple with said reference ouput; regulating means responsive to said comparison means for controlling the rate at which current is supplied to the heater bar; timing means responsive to said comparison means for controlling the length of time during which current is supplied to said heater bar; detection means for detecting a failure in said thermocouple; and disabling means responsive to said detection means for disabling the supply of current to said heater bar upon detection of a thermocouple failure.
Claim 2
Dependent Claim
120 words
In a reflow soldering system, the combination comprising: a heater bar; a thermocouple attached to said heater bar; reference means for providing a reference output corresponding to a desired heater bar temperature; comparison means for comparing the output from said thermocouple with said reference ouput; regulating means responsive to said comparison means for controlling the rate at which current is supplied to the heater bar; timing means responsive to said comparison means for controlling the length of time during which current is supplied to said heater bar; detection means for detecting a failure in said thermocouple; and disabling means responsive to said detection means for disabling the supply of current to said heater bar upon detection of a thermocouple failure.
Claim 3
Dependent Claim
120 words
In a reflow soldering system, the combination comprising: a heater bar; a thermocouple attached to said heater bar; reference means for providing a reference output corresponding to a desired heater bar temperature; comparison means for comparing the output from said thermocouple with said reference output; regulating means responsive to said comparison means for controlling the rate at which current is supplied to said heater bar; timing means responsive to said comparison means for controlling the length of time during which current is supplied to said heater bar; and disabling means for disabling the supply of current to said heater bar in response to the failure of said thermocouple output to attain a preset value within a preset period of time.
Claim 4
Dependent Claim
120 words
In a reflow soldering system, the combination comprising: a heater bar; a thermocouple attached to said heater bar; reference means for providing a reference output corresponding to a desired heater bar temperature; comparison means for comparing the output from said thermocouple with said reference output; regulating means responsive to said comparison means for controlling the rate at which current is supplied to said heater bar; timing means responsive to said comparison means for controlling the length of time during which current is supplied to said heater bar; and disabling means for disabling the supply of current to said heater bar in response to the failure of said thermocouple output to attain a preset value within a preset period of time.
Claim 5
Dependent Claim
117 words
In an a-c power supply for use in a reflow soldering system having a heater bar maintained at a potential close to ground, a thermocouple mechanically and electrically connected to said heater bar, and a welding head: means for preselecting heater bar temperature; means for preselecting ''''time-at-temperature;'''' means for preselecting a power range appropriate to the size of the heater bar in use; and means for indicating normal and abnormal operation of said system including means for detecting a failure in said connection between said thermocouple and said heater bar evidenced by the output of said thermocouple assuming a potential essentially equal to that of a bias potential connected to said thermocouple output via a bias resistor.
Claim 6
Dependent Claim
117 words
In an a-c power supply for use in a reflow soldering system having a heater bar maintained at a potential close to ground, a thermocouple mechanically and electrically connected to said heater bar, and a welding head: means for preselecting heater bar temperature; means for preselecting ''''time-at-temperature;'''' means for preselecting a power range appropriate to the size of the heater bar in use; and means for indicating normal and abnormal operation of said system including means for detecting a failure in said connection between said thermocouple and said heater bar evidenced by the output of said thermocouple assuming a potential essentially equal to that of a bias potential connected to said thermocouple output via a bias resistor.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |