US3611338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fail-safe pulse train monitor
Assignee: Honeywell Inc
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Filing: 1970-04-06
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Granted: 1971-10-05
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Expires: 1990-04-06
Abstract
Abstract Apparatus for detecting interruptions in a pulse train by causing one or more of a plurality of lamps to light if failure occurs. A bistable circuit permits certain capacitors to charge when the circuit is in one state and to discharge when the circuit is in the other state. The remaining capacitors are charged and discharged in phase opposition to this. Individual lamps are energized in accordance with the charge on the associated capacitor. The average voltage applied to each lamp is insufficient to illuminate the lamp during normal operation. Interruption of a pulse train permits the bistable circuit to remain in one state so that capacitor voltages can accumulate to a level sufficient to illuminate a lamp. The apparatus is made fail-safe by interconnecting the capacitor charging circuits so that one or more lamps are dependent upon the proper operation of every component in the circuit.
Inventors
- 👤 Melvin G Kramer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:20
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/18; H03K5/00; H03K5/22; H03K5/24
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
227 words
Apparatus for detecting interruptions in a pulse train comprising a source of energy, a four-stage regenerative bistable circuit connected in reciprocal pairs so that one pair of stages is driven into a conducting state when the other pair of stages is driven into a nonconducting state during normal operation, said bistable circuit being toggled by individual pulses in said pulse train, individual lamp circuits corresponding to each of said bistable circuit stages, each of said bistable circuit stages being connected in series with the corresponding lamp circuit across said source of energy whereby the junction voltage between the lamp circuit and the corresponding bistable circuit stage is in a low voltage state when that stage is conducting and in a high-voltage state when that stage is nonconducting, a warning lamp in each lamp circuit, a delay means in each lamp circuit arranged to provide a gradually increasing lamp voltage while the associated bistable circuit stage is conducting and a gradually decreasing voltage while the associated bistable circuit stage is not conducting, nonlinear means in each lamp circuit for providing a junction voltage that can exceed a predetermined threshold only when the lamp voltage in that stage is between specified limits, and biasing means in each bistable circuit stage adjusted to permit toggling of that stage only wHen the junction voltage driving the stage exceeds the threshold value.
Claim 2
Dependent Claim
227 words
Apparatus for detecting interruptions in a pulse train comprising a source of energy, a four-stage regenerative bistable circuit connected in reciprocal pairs so that one pair of stages is driven into a conducting state when the other pair of stages is driven into a nonconducting state during normal operation, said bistable circuit being toggled by individual pulses in said pulse train, individual lamp circuits corresponding to each of said bistable circuit stages, each of said bistable circuit stages being connected in series with the corresponding lamp circuit across said source of energy whereby the junction voltage between the lamp circuit and the corresponding bistable circuit stage is in a low voltage state when that stage is conducting and in a high-voltage state when that stage is nonconducting, a warning lamp in each lamp circuit, a delay means in each lamp circuit arranged to provide a gradually increasing lamp voltage while the associated bistable circuit stage is conducting and a gradually decreasing voltage while the associated bistable circuit stage is not conducting, nonlinear means in each lamp circuit for providing a junction voltage that can exceed a predetermined threshold only when the lamp voltage in that stage is between specified limits, and biasing means in each bistable circuit stage adjusted to permit toggling of that stage only wHen the junction voltage driving the stage exceeds the threshold value.
Claim 3
Dependent Claim
50 words
The apparatus of claim 1 wherein the delay means includes a timing capacitor connected to accumulate charge when the associated bistable circuit is in the conducting state, said capacitor being coupled to the warning lamp in the same lamp circuit so that the lamp voltage increases with increasing capacitor charge.
Claim 4
Dependent Claim
35 words
The apparatus of claim 2 in which said delay means further includes a discharge resistor connected across said timing capacitor for discharging said capacitor when the associated bistable circuit stage is in the nonconducting state.
Claim 5
Dependent Claim
65 words
The apparatus of claim 3 wherein the nonlinear means includes a lamp transistor connected in series with the lamp in that circuit, said transistor being further coupled to the capacitor in that circuit so that the conductivity of the transistor increases with increasing capacitor charge, said transistor being arranged so that the transistor saturates when the lamp voltage reaches the lower of said specified limits.
Claim 6
Dependent Claim
101 words
The apparatus of claim 1 wherein each lamp circuit includes a timing capacitor having one terminal connected to receive voltage directly from said source of energy and a series charging resistor connected between the other terminal of said capacitor and the corresponding bistable circuit stage, and wherein the warning lamp of the same lamp circuit has a first terminal connected directly to the source of energy, said lamp circuit further including a lamp transistor having an emitter electrode connected to a second terminal on said warning lamp, said lamp transistor further having base and collector electrodes connected across said series resistor.
Claim 7
Dependent Claim
53 words
The apparatus of claim 5 further including a discharge resistor connected directly across the timing capacitor, said discharge resistor having a resistance that is much larger than the resistance of said series charging resistor, and wherein the resistance of the charging resistor is large with respect to the resistance of the warning lamp.
Claim 8
Dependent Claim
66 words
The apparatus of claim 6 wherein each bistable circuit stage includes a switching transistor having base and collector electrodes connected to ground potential and to the series charging resistor of the corresponding lamp circuit respectively, said switching transistor further having a bias electrode coupled to the collector electrode of a switching transistor in one of the bistable circuit stages of the opposite of said reciprocal pairs.
Claim 9
Dependent Claim
37 words
The apparatus of claim 7 wherein said biasing means is adjusted to maintain the switching transistor in the cutoff condition when the lamp voltage in the lamp circuit driving that switching transistor is outside said specified limits.
Claim 10
Dependent Claim
24 words
The apparatus of claim 8 further including a normally closed reset switch interconnecting said voltage supply and said one terminal of the timing capacitor.
Claim 11
Dependent Claim
190 words
A signal monitor comprising first means for producing a voltage pulse train, a source of energy, a four-stage regenerative bistable circuit having the stages connected in reciprocal pairs, second means to toggle said bistable circuit in response to individual pulses from said first means, separate lamp circuits connected in series relationship with each stage in said bistable circuit, each lamp circuit and its corresponding bistable circuit stage being connected across said source of energy whereby the junction voltage between a lamp circuit and the corresponding bistable circuit stage is in a low voltage state when the stage is conducting and in a high-voltage state when that stage is nonconducting, a warning lamp in each lamp circuit, delay means in each lamp circuit for limiting the rate of change of lamp voltage, nonlinear means in each lamp circuit, said nonlinear means being adjusted so that said junction voltage can exceed a predetermined threshold only when the lamp voltage in that stage is between specified limits, and biasing means in each bistable circuit adjusted to permit toggling of that stAge only when the junction voltage driving the stage exceeds a threshold value.
Claim 12
Dependent Claim
190 words
A signal monitor comprising first means for producing a voltage pulse train, a source of energy, a four-stage regenerative bistable circuit having the stages connected in reciprocal pairs, second means to toggle said bistable circuit in response to individual pulses from said first means, separate lamp circuits connected in series relationship with each stage in said bistable circuit, each lamp circuit and its corresponding bistable circuit stage being connected across said source of energy whereby the junction voltage between a lamp circuit and the corresponding bistable circuit stage is in a low voltage state when the stage is conducting and in a high-voltage state when that stage is nonconducting, a warning lamp in each lamp circuit, delay means in each lamp circuit for limiting the rate of change of lamp voltage, nonlinear means in each lamp circuit, said nonlinear means being adjusted so that said junction voltage can exceed a predetermined threshold only when the lamp voltage in that stage is between specified limits, and biasing means in each bistable circuit adjusted to permit toggling of that stAge only when the junction voltage driving the stage exceeds a threshold value.
Claim 13
Dependent Claim
95 words
The monitor of claim 10 in which said means for producing a voltage pulse train comprises a voltage comparator, said comparator including a differential amplifier connected to receive first and second input voltages, means in said differential amplifier for producing an error voltage indicative of the difference between said first and second input voltages, a voltage-responsive oscillator responsive to said error voltage to produce a train of square wave pulses, said oscillator being adjusted to isolate only said error signal within predetermined limits, and means to couple said square wave pulses to said bistable circuit.
Claim 14
Dependent Claim
158 words
The monitor of claim 11 in which said oscillator includes a charging transistor for converting said error voltage into a corresponding charging current, a capacitor connected to receive charging current from said charging transistor, a pair of oscillator transistors connected in regenerative relationship, said oscillator transistors being connected to respond to said charging current, means to bias said oscillator transistors to a substantially cutoff condition until said charging current exceeds a first predetermined value, variable ratio voltage-dividing means coupled to said oscillator transistors, said oscillator transistors being connected to pass current from said charging transistor and said capacitor through said voltage-dividing means, said voltage-dividing means including a normally conducting diode and means to back-bias said diode when the current through said oscillator transistors exceeds a second predetermined value, and output means connected to said diode for providing a relatively low output voltage when said diode is conducting and a relatively high output voltage when said diode is back-biased.
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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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |