US3765015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switch monitoring circuitry
Assignee: EMC Corp
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Filing: 1971-09-20
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Granted: 1973-10-09
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Expires: 1991-09-20
Abstract
Abstract A system for monitoring the operation of a plurality of switches which are each connected in series with a resistor, the plurality of switch-resistor circuits being connected in parallel and in turn connected at a common point through a common resistor to a reference voltage source. In a preferred embodiment, a detector circuit is connected to the common point and is used to detect the change in voltage thereat when one or more of the switches is activated so as to provide an output voltage when such change is detected. The detector includes time delay circuitry for producing such output voltage only after the switching transient oscillation decays to a negligible value. The output voltage from the detector may be used to provide for the enabling of additional circuitry in response to such activation of one or more of the switches. If desired, an additional detector may be used to prevent such enabling when more than one switch has been activated simultaneously.
Inventors
- 👤 R Gruner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:24
CPC Classifications
H; H03; H03M; H03M11/00; H03M11/02; H03K; H03K17/00; H03K17/18; H03M11/22; H03M11/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
225 words
A switch monitor system for determining when one or more of a plurality of switches is activated, said system comprising a plurality of switch circuits each including a switch and an impedance means connected in series therewith, such switch circuits being connected in parallel with each other and having first and second common connection points, said impedance means being directly connected to said second common connection point; said first common connection point being connected to a reference point; a reference voltage source; a common impedance connected between said reference voltage source and said second common connection point, the voltage at said second common connection point having a first value when none of said switches is activated and a second value when one of said switches is activated; detector means having its input connected to said second common connection point for detecting the change in voltage at sAid second common connection point from said first value when none of said switches is activated to said second value when one of said switches is activated; encoder circuitry connected to said plurality of switch circuits for producing an encoded signal when one of said switches is activated; decoder circuitry for decoding said encoded signal; and decoder enabling circuitry responsive to the output of said detector means for enabling said decoder circuitry when one of said switches is activated.
Claim 2
Dependent Claim
225 words
A switch monitor system for determining when one or more of a plurality of switches is activated, said system comprising a plurality of switch circuits each including a switch and an impedance means connected in series therewith, such switch circuits being connected in parallel with each other and having first and second common connection points, said impedance means being directly connected to said second common connection point; said first common connection point being connected to a reference point; a reference voltage source; a common impedance connected between said reference voltage source and said second common connection point, the voltage at said second common connection point having a first value when none of said switches is activated and a second value when one of said switches is activated; detector means having its input connected to said second common connection point for detecting the change in voltage at sAid second common connection point from said first value when none of said switches is activated to said second value when one of said switches is activated; encoder circuitry connected to said plurality of switch circuits for producing an encoded signal when one of said switches is activated; decoder circuitry for decoding said encoded signal; and decoder enabling circuitry responsive to the output of said detector means for enabling said decoder circuitry when one of said switches is activated.
Claim 3
Dependent Claim
21 words
A switch monitor system as in claim 1 wherein each said series impedance means and said common impedance means are resistors.
Claim 4
Dependent Claim
22 words
A switch monitor system in accordance with claim 1 wherein the impedance values of each said series impedance means are substantially equal.
Claim 5
Dependent Claim
60 words
A switch monitor system in accordance with claim 1 wherein said voltage change at said second common connection point produces a transient oscillation when one of said switches is activated, which transient oscillation decays before reaching said second value; and further wherein said detector means produces an output signal only when said transient oscillation has decayed to a predetermined value.
Claim 6
Dependent Claim
106 words
A switch monitor system as in claim 1 wherein the voltage at said second common connection point has a third value, or lower, when two or more of said switches are activated and further including a second detector means having its input connected to said second common connection point for detecting the change in voltage at said second common connection point to a third value, or lower, when two or more of said switches are simultaneously activated; said decoder enabling circuitry being further responsive to said second detector means for preventing the enabling of said decoder circuitry when two or more of said switches are activated.
Claim 7
Dependent Claim
58 words
A switch monitor system as in claim 5 wherein said voltage change from said first value to said third value, or lower, produces a transient oscillation which decays before reaching said third value, or lower, and said second detector means includes means for producing an output signal only when said transient oscillation has decayed to a predetermined value.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |