TIRE INFLATION MONITORY SYSTEM

• US 3,581,277 A
• Filed: 10/20/1967
• Issued: 05/25/1971
• Est. Priority Date: 10/20/1967
• Status: Expired due to Term

• Current Assignee: Robert D. Beatty Jr, Thomas C. Griffiths
• Original Assignee: Robert D. Beatty Jr, Thomas C. Griffiths
• Inventors: Beatty, Robert D. Jr., Griffiths, Thomas C.
• Application Number:
  US04/676,891
• Time in Patent Office: 1,313 Days
• 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

Angular movements of wheels or other objects rotating at the same surface speed are sensed as by counting revolutions of the wheels or objects with the angular movements of the wheels or objects being compared with each other or a reference to determine whether or not one wheel or object has a smaller diameter.

Claims

1. In a vehicle, a system for sensing an underinflated tire on a first wheel thereof comprising first means responsive to the rotation of the wheel to provide an output which is a function of the angular movement of the wheel, means for providing a reference which varies with vehicle speed, second means for comparing said output with said reference to provide a signal when said output and reference compare in a predetermined manner and means responsive to said second means for indicating to an occupant of the vehicle the presence of an underinflated tire.

2. In a vehicle, the system as defined in claim 1 wherein said means for providing a reference includes rotation sensing means having a signal output which is a function of the angular movement of another part of said vehicle whose rotation is a function of vehicle speed with said signal output constituting said reference.

3. In a vehicle, the system as defined in claim 2 wherein said part is another wheel of said vehicle.

4. In a vehicle, the system as defined in claim 1 wherein said first means comprises pulse generating means for generating first pulses as a function of the rotation of said second means comprises means for counting said pulses and reference pulses constituting said reference and providing said signal when the total of the first pulses differ by a predetermined number from the total of the reference pulses.

5. In a vehicle having a plurality of wheels, first means dependent upon the angular movement of a wheel to indicate an underinflated tire thereon, and means for preventing false signals of tire underinflation while a predetermined vehicle operation condition prevails comprising control means including means for sensing said condition and means connected to the last-said means and said first means for rendering said first means ineffective while said condition prevails.

6. In a vehicle, a system for sensing an underinflated tire on a first wheel thereof comprising first means responsive to the rotation of the wheel to provide an output which is a function of the angular movement of the wheel, and second means for comparing said output with a reference which varies with vehicle speed to provide a signal when said output and reference differ in a predetermined manner, said first means comprising pulse generating means for generating first pulses as a function of the rotation of said wheel and said second means comprising means for counting said pulses and reference pulses constituting said reference and providing said signal when the total of the first pulses differ by a predetermined number from the total of the reference pulses, and wherein said means for counting is a bidirectional counter having add and subtract terminals, said first and reference pulses being applied to a respective one of said terminals.

7. In a vehicle having a plurality of wheels, a system for sensing an underinflated tire on a wheel thereof comprising first means responsive to the rotation of a first wheel of the vehicle to provide a first output which is a function of the angular movement of the first wheel, second means responsive to the rotation of a second wheel of the vehicle to provide a second output which is a function of the angular movement of the second wheel, third means responsivE to the rotation of a third wheel of the vehicle to provide a third output which is a function of the angular movement of the third wheel, fourth means responsive to the rotation of a fourth wheel of the vehicle to provide a fourth output which is a function of the angular movement of the fourth wheel, comparing means for comparing at least a pair of said outputs to determine if one of said pair of outputs results from the presence of an underinflated tire on one of the wheels with which said pair of outputs is associated, and means responsive to said comparing means for comparing said pair of outputs for indicating to an occupant of the vehicle the presence of an underinflated tire on the vehicle when one of said pair of outputs results from the presence of an underinflated tire.

8. A system for sensing an underinflated tire on a first wheel thereof comprising first means responsive to the rotation of the wheel to provide an output which is a function of the angular movement of the wheel, second means for comparing said output with a reference which varies with vehicle speed to provide a signal when said output and said reference differ in a predetermined manner, said first means comprising pulse generating means for generating first pulses as a function of the rotation of said wheel and said second means comprising means for counting said pulses and reference pulses constituting said reference and providing said signal when the total of the first pulses differ by a predetermined number from the total of the reference pulses and resetting means for periodically resetting said means for counting to a condition indicating no difference in count of said first pulses and said reference pulses.

9. In a vehicle, a system as defined in claim 8 wherein said resetting means comprises means responsive to a condition indicative of wheel revolutions of said vehicle for periodically resetting said means for counting.

10. In a vehicle, a system as defined in claim 9 wherein said resetting means comprises a counter for counting revolution pulses from a wheel of said vehicle.

11. In a vehicle, a system as defined in claim 8 wherein said means for counting is a bidirectional counter having add and subtract terminals with said first pulses and said reference pulses each being applied to a respective one of said terminals and said resetting means comprises means for setting said counter to a predetermined number.

12. In a vehicle, a system as defined in claim 8 wherein said resetting means comprises a second counter for counting pulses from a part of the vehicle which rotates as a function of vehicle speed and means responsive to said second counter for periodically resetting said bidirectional counter to a predetermined count.

13. In a vehicle, the system as defined in claim 2 wherein said first means comprises a pulse generator for generating first pulses whose number indicates revolutions of the wheel, and said means for providing a reference comprises a pulse generator responsive to rotation of said part for generating second pulses indicative of the revolutions of said part, said first and second pulses being related in a one-to-one relationship when the vehicle does not have an underinflated tire thereon, and a counter for counting said first and second pulses respectively, and providing a signal when the number of pulses counted from said part and said wheel compare in a predetermined manner.

14. In a vehicle, the system as defined in claim 13 wherein said counter is a bidirectional counter having add and subtract terminals, said first and second pulses being applied to respective ones of said terminals.

15. A method of detecting an underinflated tire on a wheel of a vehicle comprising the steps of comparing the angular velocity of said wheel with the angular velocity of a part normally driven as a function of vehicle speed, determining the presence of an underinflated tire on said wheel when the angular velocity of the part and said wheel compare in a predeterMined manner and signaling an occupant of the vehicle upon determining the presence of an underinflated tire on the wheel.

16. A method of comparing the diameters of two rotating objects which comprises the steps of driving the objects whose diameters are to be compared at the same surface speed and measuring and comparing the angular velocities thereof.

17. The method of determining the existence of an underinflated tire on a vehicle which comprises sensing and comparing the angular movements of a plurality of wheels of the vehicle while the vehicle is moving and indicating the presence of an underinflated tire on one of said plurality of wheels when the angular movements compare in a predetermined manner.

18. In a vehicle having wheels with inflated tires thereon, first means for measuring and comparing the angular movement of two of said wheels and second means for indicating the presence of an underinflated tire on one of said wheels, said second means being responsive to said first means for providing an underinflated signal to an occupant of the vehicle when the angular movements of said wheels compare in a predetermined manner.