US3587040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle detector
Assignee: Qonaar Corp
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Filing: 1968-08-12
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Granted: 1971-06-22
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Expires: 1988-08-12
Abstract
Abstract A vehicle detector, comprising a tuned inductive loop adapted to produce a high frequency field which will be disturbed by vehicles entering the field, an oscillator for supplying a high frequency energizing voltage to said loop, a phase detector for comparing the phase of said voltage across said loop with a reference voltage derived from said oscillator, said phase detector being adapted to produce a control signal when the phase of the voltage across said loop is disturbed by the entry of a vehicle into the field around the loop, an amplifier for amplifying said control signal, relay means connected to the output of said amplifier and operable in response to the amplified control signal, said relay means including a time delay circuit for restoring the relay means to its original condition if the vehicle remains in the field of the loop for longer than a predetermined time interval, and electronic means connected to the output of said amplifier for returning said loop in response to slow changes in the inductance of said loop, said electronic means including a gate circuit for preventing the retuning of said loop in response to the movement of a vehicle into the field of said loop.
Inventors
- 👤 George H Fathauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:27
CPC Classifications
G; G08; G08G; G08G1/00; G08G1/01; G08G1/042
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
A vehicle detector, comprising an inductive loop, a high frequency generator for supplying an energizing voltage to said loop, a phase detector having first and second inputs, a first output from said generator for applying the energizing voltage to said loop and to said first input whereby the phase of the voltage applied to said first input is influenced by changes in inductance of said loop, a second output for directly applying said energizing voltage to said second input to thereby provide a reference voltage at said second input, said phase detector producing a control signal in response to any change in the phase of the voltage at said first input, a third output means operable in response to said control signal from said phase detector, and retuning means for utilizing the output of said phase detector to retune the inductive loop to compensate for long term changes in the inductance thereof.
Claim 2
Dependent Claim
152 words
A vehicle detector, comprising an inductive loop, a high frequency generator for supplying an energizing voltage to said loop, a phase detector having first and second inputs, a first output from said generator for applying the energizing voltage to said loop and to said first input whereby the phase of the voltage applied to said first input is influenced by changes in inductance of said loop, a second output for directly applying said energizing voltage to said second input to thereby provide a reference voltage at said second input, said phase detector producing a control signal in response to any change in the phase of the voltage at said first input, a third output means operable in response to said control signal from said phase detector, and retuning means for utilizing the output of said phase detector to retune the inductive loop to compensate for long term changes in the inductance thereof.
Claim 3
Dependent Claim
21 words
A vehicle detector according to claim 1, including means for preventing the vehicle detection control signal from operating said retuning means.
Claim 4
Dependent Claim
40 words
A vehicle detector according to claim 1, including gating means operable in response to the detection control signal for effectively disconnecting said retuning means from said phase detector to prevent said vehicle detection control signal from actuating said retuning means.
Claim 5
Dependent Claim
44 words
A vehicle detector according to claim 3, in which said gating means includes a gating diode connected between said phase detector and said retuning means, and means operable by the vehicle detection control signal for reversely biasing said gating diode to render it nonconductive.
Claim 6
Dependent Claim
42 words
A vehicle detector according to claim 3, in which said gating means comprises a gating diode, and means including a field effect transistor for reversely biasing said gating diode in response to the vehicle detection control signal to render said diode nonconductive.
Claim 7
Dependent Claim
59 words
A vehicle detector according to claim 3, in which said retuning means comprises a field effect transistor having its control electrode connected to said gating means, and a storage capacitor connected to said control electrode for maintaining the voltage on said control electrode when said gating meAns is operative to disconnect said field effect transistor from said phase detector.
Claim 8
Dependent Claim
53 words
A vehicle detector according to claim 3, including timing means for restoring said gating means to its original condition after a predetermined time interval whereby said retuning means will be effective to tune out the vehicle detection control signal if the vehicle remains in the field of the loop beyond said time interval.
Claim 9
Dependent Claim
29 words
A vehicle detector according to claim 1, including gating means operable by the vehicle detection control signal for preventing the vehicle detection control signal from actuating the retuning means.
Claim 10
Dependent Claim
56 words
A vehicle detector according to claim 8, in which said timing means is constructed and arranged to restore said gating means to its initial condition after the predetermined time interval whereby said retuning means will then tune out the vehicle detection control signal so that the vehicle detector will be fully operative to detect another vehicle.
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) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |