TIRE INFLATION MONITORING SYSTEM

• US 3,691,524 A
• Filed: 06/15/1970
• Issued: 09/12/1972
• Est. Priority Date: 06/15/1970
• Status: Expired due to Term

• Current Assignee: Harold A. Frost, Melvin R. Simpson
• Original Assignee: Harold A. Frost, Melvin R. Simpson
• Inventors: Frost, Harold A., Simpson, Melvin R.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Wannisky, William M.
• Application Number:
  US05/045,954
• Time in Patent Office: 820 Days
• Field of Search: 340/58,263,27 324/160,161,163,166,78R,78D 307/123 180/82,103 303/21A,21CE 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

An improved tire inflation monitoring system monitors the angular movement of the wheels of a vehicle by counting the revolutions on each of the wheels and comparing the count with a count from another wheel to determine whether or not each wheel has the proper diameter. The monitoring system includes an indicating means for signaling an occupant of the vehicle when a tire thereon is underinflated and means responsive to the relative rotation of the wheels for preventing false indications of tire underinflation due to slipping of the wheels of the vehicle or to turning of the vehicle.

Claims

1. A tire inflation monitoring system for a vehicle having a plurality of wheels which rotate in engagement with the supporting surface for the vehicle as the vehicle moves, said wheels including a first wheel having an inflated tire thereon and a second wheel which rotates relative to said first wheel when said tire is underinflated and also during a temporary operating condition for said vehicle which effects relative rotation of said first wheel and said second wheels when said tire is properly inflated, said wheels including a third wheel which rotates relative to one of the vehicle wheels during said temporary operating condition, first means responsive to angular rotation of said first and second wheels for signalling an underinflated tire on said first wheel, and second means responsive to the rotation of said third wheel relative to said one of said wheels for rendering said first means ineffective to render a signal indicating that said tire is underinflated during said temporary operating condition which effects relative rotation of said first and second wheels.

2. A tire inflation monitoring system as defined in claim 1 wherein said first and second wheels are drive wheels for said vehicle and said third wheel is a non-driving wheel, and said second means is responsive to differences in angular rotation of said third wheel relative to one of said first and second wheels.

3. A tire inflation monitoring system as defined in claim 1 wherein said one wheel is a fourth wheel with said second and fourth wheels being on one side of the vehicle and said first wheel and said third wheel being on the opposite side of said vehicle, said second means being responsive to differences in the angular rotation of said third wheel and said fourth wheel to render said first means ineffective during turning of said vehicle.

4. A tire inflation monitoring system as defined in claim 1 wherein said one wheel is a fourth wheel with said second and fourth wheels being on one side of the vehicle and said first and third wheels being on the opposite side of the vehicle, said second means being responsive to the relative rotation of said third and fourth wheels and being operable to render said first means ineffective to render a false signal indicative that said tire is underinflated when said third and fourth wheels are rotating relative to each other in the same manner as said first and second wheels are rotating relative to each other and said first and second wheels rotate relative to each other so that said first means senses a condition indicative of said tire being underinflated.

5. A tire inflation monitoring system for a vehicle having a plurality of wheels which engage and rotate on the supporting surface for the vehicle as the vehicle moves comprising signalling means for signalling an underinflated tire, first means responsive to the relative angular velocity of a first pair of said wheels for monitoring the inflation of a tire on one of the wheels and activating said signalling means in response to said first pair of wheels rotating relative to each other in a predetermined manner thereon, and second means responsive to the relative angular velocity of a different pair of said wheels on said vehicle for rendering said first means ineffective to activate said signalling means during a temporary vehicle operating condition under which said first means may operate to falsely indicate an under inflated tire.

6. In a vehicle having a plurality of wheels and an inflated tire on a wheel, a tire inflation monitoring system comprising first means responsive to angular movement of said wheels for sensing underinflation of said tire, indicating means responsive to said first means for signalling the presence of an underinflated tire and means responsive to the relative rotation of the wheels for preventing false indications of tire underinflation due to rotation of one of the wheels relative to another of the wheels.

7. In a vehicle a tire inflation monitoring system as defined in claim 6 wherein said means responsive to the relative rotation of the wheels includes means for preventing false indications of tire underinflation due to turning of the vehicle.

8. In a vehicle, a tire inflation monitoring system as defined in claim 7 wherein said means for preventing false indications of tire underinflation due to turning of the vehicle includes means responsive to the underinflation of said tire when the vehicle is turning which actuate said indicating means so as to signal the presence of an underinflated tire on the vehicle.

9. In a vehicle, a tire inflation monitoring system as defined in claim 6 wherein said means responsive to the relative rotation of said wheels includes means for preventing false indications of tire underinflation due to slipping of one wheel of the vehicle relative to another wheel of the vehicle.

10. In a vehicle, a tire inflation monitoring system as defined in claim 9 wherein said means responsive to the relative rotation of said wheels further includes means for preventing false indications of tire underinflation due to turning of the vehicle.

11. In a vehicle, a tire inflation monitoring system as defined in claim 7 wherein said first means includes a first and second bi-directional counter means each of which compares the speed at which a pair of the wheels on the vehicle rotate and which effect the actuation of said indicating means when the rate of rotation of one of the wheels of one of said pair of wheels is a predetermined amount greater than the other wheel of said one pair of wheels.

12. In a vehicle, a tire inflation monitoring system as defined in claim 11 wherein said means for preventing false indications of underinflation of said tire due to turning of the vehicle includes means for preventing said bi-directional counter means from effecting the actuation of said indicating means when one of each of said pair of wheels is rotating faster than the other of each of said pair of wheels due to turning of the vehicle and wherein said faster rotating wheels are necessarily located on the same side of the vehicle.

13. In a vehicle, a tire inflation monitoring system as defined in claim 9 wherein said means for preventing false indications of underinflation of said tire due to slipping of one wheel of the vehicle relative to another wheel of the vehicle includes a plurality of counter means one of which is associated with each of the wheels of the vehicle, each of said counter means being reset to an initial condition once for every rotation of a wheel of the vehicle which is other than the counters associated wheel, each of said counters being operable to count the revolutions of its associated wheel and effect a signal therefrom to prevent said indicating means from indicating underinflation of said tire if the counter'"'"''"'"'s associated wheel rotates a predetermined number of revolutions before said counter is reset by one rotation of said other wheel to thereby indicate that said associated wheel is travelling a plurality of times faster than said other wheel which necessarily means said associated wheel is slipping.

14. A tire inflation monitoring system as defined in claim 5 wherein said second means comprises means responsive to the angular rotation of said different pair of wheels for activating said signalling means to indicate an underinflated tire on one of said different pair of wheels and said first means comprises means responsive to the relative angular velocity of said first pair of wheels for renDering said second means ineffective to activate said signalling means during predetermined operating conditions.

15. A tire inflation monitoring system as defined in claim 14 wherein said pairs of wheels comprise four wheels and said wheels each have a tire thereon to be monitored and said first and second means each comprise first and second control elements respectively activated when the angular velocities of the wheels of the respective pair have relative angular velocities in a respective direction to indicate tire underinflation and said first means being responsive to the direction of angular velocity of said first pair of wheels to render a respective one of said first and second elements of said second means ineffective to activate said signalling means for a respective direction of relative rotation of said different pair of wheels and said second means being comprised of means responsive to the direction of relative rotation of said different pair of wheels to render a respective one of said first and second elements of said first means ineffective to activate said signalling means for a respective direction of angular rotation of said first pair of wheels.

16. A tire inflation monitoring system as defined in claim 15 wherein said first and second means each comprise a bi-directional counter having plus and minus input terminals for counting in respective directions and a respective pulse generator for each wheel for supplying pulses to a respective one of said plus and minus terminals, said counters each having first and second count outputs for plus and minus counts from a predetermined reference count connected to activate respective ones of said first and second control elements of the other of said first and second means and second and third count outputs for indicating plus and minus counts respectively which are higher than the counts said first and second count outputs for activating respective ones of said first and second control elements of the corresponding one of said first and second means.

17. In a tire inflation monitoring system as defined in claim 5 wherein said second means comprises means responsive to a predetermined difference in rotation between said different pair of said wheels to render said first means ineffective to activate said signalling means in response to relative rotation of said first pair of wheels in said predetermined manner.