Patent US3858174A successfully refreshed from Google Patents.
US3858174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tire pressure monitoring system
Assignee: Lucas Electrical Co Ltd
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Filing: 1973-07-26
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Granted: 1974-12-31
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Expires: 1993-07-26
Abstract
Abstract A tire pressure monitoring system has a tuned circuit rotating with the tire to be monitored. The tuned circuit incorporates a pressure-responsive switch, and energy is applied to the tuned circuit by a transmitter. A receiver detects energy in the tuned circuit, and the transmitter transmits signals over a band of frequencies including the resonant frequency of the tuned circuit.
Inventors
- 👤 P Harris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:30
CPC Classifications
B; B60; B60C; B60C23/00; B60C23/02; B60C23/04; B60C23/0408; B60C23/0422; B60C23/0427; B60C23/0428
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
108 words
A tire pressure monitoring system including a tuned circuit rotating with the tire to be monitored, the tuned circuit including a pressure-responsive switch, said system further including a variable frequency transmitter supplying energy to the tuned circuit, a controller producing a ramp voltage at a predetermined frequency which is low relative to the frequency range of said transmitter, means coupling said controller to said transmitter, the frequency of said transmitter being determined by said ramp voltage, whereby said transmitter transmits signals over a band of frequencies, and a receiver for detecting energy in the tuned circuit, said band of frequencies including the resonant frequency of the tuned circuit.
Claim 2
Dependent Claim
108 words
A tire pressure monitoring system including a tuned circuit rotating with the tire to be monitored, the tuned circuit including a pressure-responsive switch, said system further including a variable frequency transmitter supplying energy to the tuned circuit, a controller producing a ramp voltage at a predetermined frequency which is low relative to the frequency range of said transmitter, means coupling said controller to said transmitter, the frequency of said transmitter being determined by said ramp voltage, whereby said transmitter transmits signals over a band of frequencies, and a receiver for detecting energy in the tuned circuit, said band of frequencies including the resonant frequency of the tuned circuit.
Claim 3
Dependent Claim
37 words
A system as claimed in claim 1 in which the output frequency of the receiver is compared with the output frequency of the ramp voltage, and a warning is given only if the compared frequencies are unequal.
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) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |