Communications: electrical – Selective – Having indication or alarm
Patent
1977-02-15
1978-08-29
Caldwell, Sr., John W.
Communications: electrical
Selective
Having indication or alarm
303 95, 361244, 361203, 324 83R, 324167, B60C 2300
Patent
active
041107322
ABSTRACT:
Low pressure in a vehicle tire is detected by an electronic system which compares the difference in phase between two cyclic signals and produces an output signal having a negative going pulse and a positive going pulse for each revolution of the tire. Each negative going pulse represents a decrease in phase between the two signals and is generated in response to a shorted coil passing through an electromagnetic field produced by an induction coil in a parallel resonant circuit which produces the second of the two signals. The first signal is produced by an oscillator and is used to excite the resonant circuit and as a reference signal. The coil is shorted by a closed switch in the tire when the pressure is normal. Abnormal tire pressure opens the switch and renders the coil ineffective. Each positive going pulse represents an increase in phase between the two signals and is generated in response to a ferrous metal plate passing through the field. A logic circuit includes a capacitor charged at a fixed rate and operative to activate a warning light when the capacitor charge exceeds a predetermined level. When the tire speed is above 5 mph, the negative going pulses cause the capacitor to discharge faster than it is charged. When the vehicle speed is below 5 mph, a low speed inhibit circuit responsive to the positive going pulses discharges the capacitor faster than it is charged.
REFERENCES:
patent: 3206641 (1965-09-01), Leeson
patent: 3525103 (1970-08-01), McCune
patent: 3665387 (1972-05-01), Enabnit
patent: 3911934 (1975-10-01), Cook
patent: 3990041 (1976-11-01), Blanchier
Jarocha William M.
O'Neil Walter K.
Caldwell Sr. John W.
Crosland Donnie L.
Eaton Corporation
Sajovec, Jr. F. M.
LandOfFree
Tire pressure monitor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tire pressure monitor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tire pressure monitor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1636295