TIRE INFLATION MONITORING SYSTEM

• US 3,613,075 A
• Filed: 10/16/1969
• Issued: 10/12/1971
• Est. Priority Date: 10/16/1969
• Status: Expired due to Term

• Current Assignee: Melvin R. Simpson, Thomas C. Griffiths
• Original Assignee: Melvin R. Simpson, Thomas C. Griffiths
• Inventors: Griffiths, Thomas C., Simpson, Melvin R.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US04/867,046
• Time in Patent Office: 726 Days
• Field of Search: 340/27,58,262 303/21A,21CE,21CF,21CG 180/82,103 73/146.2,146.3,146.4,146.5
• US Class Current: 340/444
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

Tire inflation is monitored by sensing the angular movement of a wheel by counting revolutions of the wheel and comparing the count with a count from another wheel or a reference to determine whether or not the wheel has the proper diameter. A low speed reset system is provided to prevent false indications that might occur when the vehicle is operating at slow speeds.

Claims

1. In a vehicle having a wheel and an inflated tire on the wheel, a tire inflation monitoring system comprising first means responsive to the angular movement of said wheel for providing a signal indicating the rate of angular movement of said wheel, second means providing a signal related to vehicle velocity, third means, including counting means for counting pulses indicative of the rotation of said wheel and said vehicle velocity, for comparing said signals, fourth means responsive to an outpuT signal from said third means for indicating an underinflated tire on said wheel, and frequency responsive control means including first circuit means responsive to pulses indicative of vehicle velocity having a frequency below a predetermined level and operative upon sensing of said low frequency pulses for repeatedly resetting said counting means while the frequency of said pulses from the vehicle velocity remain below said predetermined level.

2. In a tire monitoring system as defined in claim 1 wherein said circuit comprises storage means for storing an electrical quantity with the magnitude of the quantity stored therein being a time function of the magnitude of an electrical signal applied thereto, means for applying an electrical signal to said storage means, and means responsive to said pulses indicative of vehicle speed for repeatedly discharging said storage means at a frequency dependent on the pulse frequency, said circuit effecting a resetting of said counting means when said storage means has a predetermined magnitude of said electrical quantity stored therein.

3. In a tire monitoring system as defined in claim 2 wherein said storage means comprises a condenser and said means responsive to said pulses to discharge said storage means is responsive to each pulse to effect a discharge of said condenser.

4. In a tire monitoring system as defined in claim 1 wherein said control means comprises a storage circuit for storing an electrical quantity in response to an electrical signal applied thereto with the magnitude of the stored quantity being a time function of the magnitude of said electrical signal, means for applying an electrical signal to said storage circuit for establishing a stored quantity therein and circuit means for periodically discharging said stored quantity at a frequency which is a function of wheel speed, and means responsive to the magnitude of said stored quantity to render said tire monitoring system ineffective.

5. In a tire monitoring system as defined in claim 4 wherein said storage means comprises a condenser charged by said electrical signal.

6. In a tire monitoring system as defined in claim 1 wherein said pulses indicative of vehicle speed are derived from a pulse generator responsive to the rotation of the front wheel of the vehicle.

7. In a tire monitoring system as defined in claim 4 wherein said pulses indicative of vehicle speed are from a pulse generator responsive to the rotation of the vehicle wheel and said control means is responsive to said pulses.

8. In a tire monitoring system as defined in claim 7 wherein said pulse generator is responsive to the rotation of a front wheel of said vehicle.