US3757207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for testing thermostatic switches
Assignee: Fasco Controls Corp
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Filing: 1972-01-10
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Granted: 1973-09-04
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Expires: 1992-01-10
Abstract
Abstract Thermostatic switches to be tested are placed in an oven containing a thermocouple connected in normal manner by two lead wires to the input of a conventional temperature recorder of the drag pen variety. Each switch is connected to one of a plurality of timer devices which control normally-open switches connected in parallel across the two lead wires of the thermocouple. As the oven temperature increases a time-temperature curve is inscribed on the chart in the recorder. As each thermostat trips it actuates its timer device, which in turn momentarily closes its associated switch to shunt the lead wires, thus causing the drag pen to shift laterally and mark a line transverse of said curve at the exact temperature the thermostat tripped. Each timer closes its switch for a different interval so that each thermostat is identified by the length of the transverse mark it causes.
Inventors
- 👤 C Hire
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:47
CPC Classifications
G; G01; G01K; G01K15/00; G01D; G01D18/00; G01R; G01R31/00; G01R31/50
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
153 words
The method of checking a plurality of switches which move between open and closed positions, respectively, in response to predetermined changes in an external condition, comprising subjecting all of said switches to a controlled, external condition, the magnitude of which is changed over a period of time from a first to a second limit to effect movement of said switches between their open and closed positions, developing during said period a signal the magnitude of which at any instant is proportionate to the magnitude of said condition, producing a graphic record of the rate of change in the magnitude of said signal, momentarily interrupting said signal for different intervals of time for the different switches, respectively, each time one of said switches moves between its open and closed positions, and using said interruptions to mark said graphic record at the exact points thereon where said switches move between their open and closed positions.
Claim 2
Independent Claim
153 words
The method of checking a plurality of switches which move between open and closed positions, respectively, in response to predetermined changes in an external condition, comprising subjecting all of said switches to a controlled, external condition, the magnitude of which is changed over a period of time from a first to a second limit to effect movement of said switches between their open and closed positions, developing during said period a signal the magnitude of which at any instant is proportionate to the magnitude of said condition, producing a graphic record of the rate of change in the magnitude of said signal, momentarily interrupting said signal for different intervals of time for the different switches, respectively, each time one of said switches moves between its open and closed positions, and using said interruptions to mark said graphic record at the exact points thereon where said switches move between their open and closed positions.
Claim 3
Independent Claim
116 words
The method of checking thermostatic switches which operate to move between open and closed positions, respectively, in response to different ambient temperatures, comprising placing said switches in a controlled temperature ambient, changing said ambient temperature from a first to a second value to effect operation of said switches, developing an electrical signal the magnitude of which at any instant is proportionate to said ambient temperature, using said signal automatically to prepare a record of the gradient of said ambient temperature, and momentarily interrupting said signal for different intervals of time for the different switches, respectively, when said siwtches move between open and closed positions to indicate on said record the temperatures at which said switches operate.
Claim 4
Independent Claim
116 words
The method of checking thermostatic switches which operate to move between open and closed positions, respectively, in response to different ambient temperatures, comprising placing said switches in a controlled temperature ambient, changing said ambient temperature from a first to a second value to effect operation of said switches, developing an electrical signal the magnitude of which at any instant is proportionate to said ambient temperature, using said signal automatically to prepare a record of the gradient of said ambient temperature, and momentarily interrupting said signal for different intervals of time for the different switches, respectively, when said siwtches move between open and closed positions to indicate on said record the temperatures at which said switches operate.
Claim 5
Dependent Claim
54 words
The method as defined in claim 2 wherein said signal inscribes a curve representing the rate of change of said ambient temperature, developing a second signal each time the first-named signal is interrupted, and using said second signal for inscribing a line transverse to said curve each time one of said switches is operated.
Claim 6
Dependent Claim
130 words
Apparatus for checking the operation of condition-responsive electrical switches, comprising a chamber for holding a plurality of said switches, means for simultaneously varying the magnitude of an ambient condition of all said switches, means for developing an electrical signal the magnitude of which varies in proportion to the variation in magnitude of said condition, recording means responsive to said signal to produce a graphic representation of the magnitude of said condition at any instant, and means for momentarily interrupting said signal for different time intervals, respectively, when different said switches operate, said recording means being operative to place a different mark on said graphic representation each time said signal is interrupted, said marks indicating, respectively, the magnitude of said condition at the moment a particular one of said switches operated.
Claim 7
Dependent Claim
130 words
Apparatus for checking the operation of condition-responsive electrical switches, comprising a chamber for holding a plurality of said switches, means for simultaneously varying the magnitude of an ambient condition of all said switches, means for developing an electrical signal the magnitude of which varies in proportion to the variation in magnitude of said condition, recording means responsive to said signal to produce a graphic representation of the magnitude of said condition at any instant, and means for momentarily interrupting said signal for different time intervals, respectively, when different said switches operate, said recording means being operative to place a different mark on said graphic representation each time said signal is interrupted, said marks indicating, respectively, the magnitude of said condition at the moment a particular one of said switches operated.
Claim 8
Dependent Claim
76 words
Apparatus as defined in claim 4, whErein said interrupting means comprises a plurality of timer devices interposed between said recording means and said signal developing means, and means connecting each of said switches to a different one of said timer devices, and operative each time one of said switches is operated to energize the timer device connected thereto, said timer devices being operative, when energized, to effect interruption of said signal for different time intervals, respectively.
Claim 9
Dependent Claim
136 words
Apparatus for determining the temperatures at which thermostatic switches operate to move fron one to the other of their open and closed positions, respectively, comprising means for simultaneously subjecting a plurality of said switches to an ambient temperature which changes in value to effect operation of said switches, means for developing a first electrical signal having a magnitude proportionate at any instant to the value of said temperature, a temperature recorder responsive to said first signal to inscribe a curve representating the rate of change in the value of said temperature, and means connecting said switches between said recorder and said signal developing means and operative, each time one of said switches operates, to cause said recorder to inscribe transverse to said curve a line, the lengths of said lines being different for the different switches.
Claim 10
Dependent Claim
136 words
Apparatus for determining the temperatures at which thermostatic switches operate to move fron one to the other of their open and closed positions, respectively, comprising means for simultaneously subjecting a plurality of said switches to an ambient temperature which changes in value to effect operation of said switches, means for developing a first electrical signal having a magnitude proportionate at any instant to the value of said temperature, a temperature recorder responsive to said first signal to inscribe a curve representating the rate of change in the value of said temperature, and means connecting said switches between said recorder and said signal developing means and operative, each time one of said switches operates, to cause said recorder to inscribe transverse to said curve a line, the lengths of said lines being different for the different switches.
Claim 11
Dependent Claim
118 words
Apparatus as defined in claim 6, wherein said connecting means comprises a plurality of timer devices equal in number to said switches, and means connecting said switches, respectively, to different said devices and operative, when one of said switches is operated, to energize the timer device connected thereto, each of said devices being operative, when energized, momentarily to apply to said recorder a second signal having a duration which is different for each of said devices and is dependent upon the time the associated timer device is energized, said second signals being operative to cause said recorder to inscribe said transverse lines having lengths proportionate, respectively, to the durations of the signals produced by said different devices, respectively.
Claim 12
Dependent Claim
136 words
Apparatus as defined in claim 7, wherein said first signal developing means comprises a thermocouple exposed to said ambient temperature and connected by a pair of wire leads to said recorder normally to vary the magnitude of said first signal in proportion to the change in said ambient temperature, and said connecting means further comprises a second plurality of switches connected to at least one of said leads and responsive to said timer devices, each of said timer devices being operative, when energized, momentarily to move an associated one of said second plurality of switches from a first to a second position in which the last-named switch causes said second signal to be applied to said recorder for a predetermined duration, the different timer devices operating to produce said second signal for different predetermined durations, respectively.
Claim 13
Dependent Claim
130 words
Apparatus for testing the temperatures at which different thermostatic switches move from one to the other of their open and closed positions, comprising means for simultaneously subjecting a plurality of said switches to changing ambient temperature to effect operation of the switches, a temperature recorder, a thermocouple exposed to said ambient temperature, an electrical circuit operatively connecting said thermocouple to said recorder to cause recording of said varying ambient temperature, a plurality of timers, one of which is connected to each thermostatic switch, and a pluraity of switches, one of which is connected to each different timer only, and each of which is connected across said electrical circuit to short out said thermocouple for a time interval determined by the associated timer, said different timers operating for different time intervals.
Claim 14
Dependent Claim
130 words
Apparatus for testing the temperatures at which different thermostatic switches move from one to the other of their open and closed positions, comprising means for simultaneously subjecting a plurality of said switches to changing ambient temperature to effect operation of the switches, a temperature recorder, a thermocouple exposed to said ambient temperature, an electrical circuit operatively connecting said thermocouple to said recorder to cause recording of said varying ambient temperature, a plurality of timers, one of which is connected to each thermostatic switch, and a pluraity of switches, one of which is connected to each different timer only, and each of which is connected across said electrical circuit to short out said thermocouple for a time interval determined by the associated timer, said different timers operating for different time intervals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |