Patent US3725748A successfully refreshed from Google Patents.
US3725748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-adjusting condition-responsive control circuit
Assignee: Cooper Industries LLC
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Filing: 1971-11-08
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Granted: 1973-04-03
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Expires: 1991-11-08
Abstract
Abstract The output of an oscillator is normally continuously varied within predetermined limits so that a first, load-controlling relay is normally de-energized and a second relay is normally energized and de-energized alternately to continuously vary the input voltage to a filed-effect transistor connected in the output of said oscillator. Thus, the circuit ''''hunts'''' about a reference level of detected capacitance and compensates for both slow variations from that reference level and drift in values of circuit elements, but will cause a load to become energized in response to a rapid change in detected capacitance.
Inventors
- 👤 C Atkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:02
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/955
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A self-adjusting, condition-responsive control circuit comprising: 1 first circuit means operative to generate a continuouslyvarying signal in the presence and absence of variations in ambient conditions, and further operative to alter the energization state of a load in response to rapid variations from a reference level of a monitored parameter; and 2 second circuit means operative in response to said continuously varying signal received from said first circuit means to adjust said reference level in response to slow variations in said monitored parameter.
Claim 2
Dependent Claim
83 words
A self-adjusting, condition-responsive control circuit comprising: 1 first circuit means operative to generate a continuouslyvarying signal in the presence and absence of variations in ambient conditions, and further operative to alter the energization state of a load in response to rapid variations from a reference level of a monitored parameter; and 2 second circuit means operative in response to said continuously varying signal received from said first circuit means to adjust said reference level in response to slow variations in said monitored parameter.
Claim 3
Dependent Claim
62 words
The control circuit according to claim 1 wherein said first circuit means comprises a low-frequency relaxation oscillator having a voltage-controlled variable resistance connected in its output branch, said oscillator being operative to produce said continuously varying signal in the form of output pulses which are normally varied between predetermined upper and lower limits in response to variations in said voltage-controlled variable resistance.
Claim 4
Dependent Claim
26 words
The control circuit according to claim 2 wherein said voltage-controlled variable resistance is provided with a normally continuously varying control voltage by said second circuit means.
Claim 5
Dependent Claim
83 words
The control circuit according to claim 3 wherein said first circuit means comprises a two-stage amplifier operative to amplify the output signal of said oscillator, a first switching circuit controlled by the output of said amplifier, and first rectifying and current-smoothing circuit means connected between said switching circuit and a first, load-controlling relay to enable continuous energization of said first relay when said first switching circuit is non-conductive and to prevent energization of said first relay when said first switching circuit is conductive.
Claim 6
Dependent Claim
66 words
The control circuit according to claim 4 wherein said first, load-controlling relay comprises first and second armatures operative to control first and second pairs of contacts, respectively, said first pair of contacts being operative to control the energization state of a load and said second pair of contacts being operative to make or break the connection between said second circuit means and said voltage-controlled variable resistance.
Claim 7
Dependent Claim
27 words
The control circuit according to claim 4 wherein said continuously varying signal received from said first circuit means is derived from said first stage of said amplifier.
Claim 8
Dependent Claim
33 words
The control circuit according to claim 2 wherein said second circuit means comprises charging/discharging circuit means operative to provide said normally continuously varying control voltage to said voltage-controlled variable resistance in said oscillator.
Claim 9
Dependent Claim
54 words
The control circuit according to claim 7 wherein said charging/discharging circuit means comprises a capacitance, a second relay having its armature connected to the high terminal of said capacitance and having first and second contacts engageable by said armature to connect said capacitance to a charging current path or a discharging current path, respectively.
Claim 10
Dependent Claim
26 words
The control circuit according to claim 8 wherein the voltage across said capacitance comprises the normally continuously varying control voltage provided to said voltage-controlled variable resistance.
Claim 11
Dependent Claim
85 words
The control circuit according to claim 8 wherein said second relay is controlled by a second switching circuit which is normally rendered alternately conductive and non-conductive in response to said continuously varying signal received from said first circuit meaNs and is connected to said second relay by second rectifying and current smoothing circuit means operative to enable continuous energization of said second relay when said second switching circuit is non-conductive and to prevent energization of said second relay when said second switching circuit is conductive.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |