Trailer tire pressure-monitoring system

• US 6,246,316 B1
• Filed: 02/23/2000
• Issued: 06/12/2001
• Est. Priority Date: 02/23/2000
• Status: Expired due to Fees

• Current Assignee: Richard L. Andsager
• Original Assignee: Richard L. Andsager
• Inventors: Andsager, Richard L.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): TANG, SON M
• Application Number:
  US09/511,558
• Time in Patent Office: 475 Days
• Field of Search: 340/444, 340/442, 340/443, 340/448
• 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

A tire pressure-monitoring system for use with a trailer. The monitoring system includes an inductive proximity sensor mounted adjacent each wheel. To activate the sensors, a target is mounted on each brake drum. Rotational speed data for each wheel is relayed from each sensor to a programmable logic controller which compares the rotational speed of a wheel with another wheel. Sensitivity parameters written into the program contained in the programmable logic controller compares the input data and, if the data falls outside the safe parameters, alerts the driver by activating and audio or visual alarm mounted within the tow vehicle. The sensitivity of the programmed logic may be optimized to differentiate changes in a tire diameter due to turning versus an actual loss in tire pressure.

Claims

1. A low tire pressure alarm system for sensing abnormal rotational speeds of a plurality of wheels on a trailer adapted for coupling to a tow vehicle comprising, in combination:

a) a plurality of target means, each said target means being constructed and arranged for mounting adjacent to each of at least two of the wheels, for providing a sensing target rotating with each of the wheels;

b) a plurality of sensing means, each said sensing means being constructed and arranged for non-rotatable attachment to the trailer, for sensing rotations of one said target means past one said sensing means and for generating signals directly representing rotational speeds;

c) a compilation means, coupled to each said sensing means, for receiving said signals directly representing rotational speeds from each said sensing means and for using said signals for computing and comparing rotational speeds of the wheels; and

d) alarm indicator means, constructed and arranged for attachment to the tow vehicle and for coupling to said compilation means, for providing an indication of an abnormal rotational speed of a wheel.

2. The system of claim 1 wherein said compilation means is constructed and arranged for attachment to the trailer.

3. The system of claim 2 wherein said compilation means comprises a power means for assisting powering of said sensing means and said compilation means.

4. The system of claim 3 wherein said compilation means comprises a programmable logic controller.

5. The system of claim 4 wherein said compilation means further comprises programming means for programming said programmable logic controller for counting rotations of each of a plurality of the trailer wheels within the same fixed time period in such manner as to provide less sensitivity to rotational-count differences at lower trailer speeds.

6. The system of claim 5 wherein:

(a) each said target means comprises a protuberance constructed and arranged to extend from one of the wheels of the trailer;

(b) said alarm indicator means comprises an alarm constructed and arranged for mounting in the tow vehicle; and

(c) each said sensing means is constructed and arranged for attachment to an axle of the trailer.

7. The system of claim 6 wherein said target means is structured and arranged for attachment to a brake drum of one of the wheels of the trailer.

8. The system of claim 1 wherein each said target means comprises a protuberance constructed and arranged to extend from one of the wheels of the trailer.

9. The system of claim 8 wherein said protuberance comprises a mechanical fastener constructed and arranged for attachment to normally rotating parts of the wheel.

10. The system of claim 1 wherein each said sensing means comprises an induction proximity sensor.

11. The system of claim 1 wherein said alarm indicator means comprises an alarm constructed and arranged for mounting in the tow vehicle.

12. The system of claim 11 wherein said alarm comprises an audio alarm structured and arranged for mounting in the tow vehicle.

13. The system of claim 11 wherein said alarm comprises a visual light structured and arranged for mounting in the tow vehicle.

14. The system of claim 1 wherein said sensing means is constructed and arranged for attachment to an axle of the trailer.

15. A low tire pressure alarm system for sensing abnormal rotational speeds of a plurality of wheels on a trailer adapted for coupling to a tow vehicle comprising, in combination:

a) a trailer having at least two wheels;

b) a plurality of metal targets, each said target being mounted adjacent to one of said wheels in such manner as to provide a sensing target rotating with each of said wheels;

c) a plurality of sensors, each said sensor being attached non-rotatably to said trailer in such manner as to sense rotations of one said target past one said sensor and to generate signals directly representing rotational speeds;

d) a computer mounted on said trailer and coupled to each said sensor, said computer being structured and arranged so as to receive said signals directly representing rotational speeds from each said sensor and to use said signals to compare said direct representations of rotational speeds of said wheels; and

e) a trailer coupler constructed and arranged to assist in system coupling of said computer to an alarm indicator within a tow vehicle of a type adapted to attach to said trailer.

16. The system of claim 15 further comprising:

(a) a tow vehicle of a type adapted to attach to said trailer; and

(b) an alarm indicator attached to said tow vehicle, said alarm indicator being constructed and arranged for coupling to said computer in such manner as to provide an indication of an abnormal rotational speed of a said wheel.

17. The system of claim 15 wherein each said sensor is non-rotatably attached to an axle of said trailer.

18. The system of claim 17 wherein each said sensor is a proximity sensor.

19. The system of claim 18 wherein each said target comprises a protuberance extending from and rotatably attached with one said wheel.

20. The system of claim 19 wherein each said protuberance is connected to a brake drum of one said wheel.

21. The system of claim 15 further comprising a programming means for programming said computer for counting rotations of each of a plurality of said wheels of said trailer within the same fixed time period in such manner as to provide less sensitivity to rotational-count differences at lower trailer speeds.

22. A method for sensing abnormal rotational speeds of a plurality of wheels, each coupled to air-pressure-filled tires having an optimal air pressure amount, on a trailer towable by a tow vehicle traveling at a land speed, and alerting a driver of the tow vehicle of the abnormal condition, comprising the steps of:

a) providing one proximity sensor for each of said wheels;

b) detecting each rotation of each said wheel by means of the operation of each said proximity sensor;

c) computer-storing data directly associated with said rotations of each said respective wheel for a selected time period;

d) computer-calculating the difference between the number of rotations of at least two said wheels in said time period; and

e) producing a warning signal in said tow vehicle when said differential achieves a selected value.

23. The method of claim 22 wherein said warning signal is indicated when the value of said difference is at least 3 within a 10-second period.

24. The method of claim 22 wherein said production of said warning signal becomes less sensitive at progressively decreasing land speeds, whereby the difference in rotational speeds of said wheels on opposed sides of said trailer while said trailer is merely turning does not produce a said warning signal.

25. A method of installing a low tire pressure alarm system for sensing abnormal rotational speeds of a plurality of wheels on a trailer adapted for coupling to a tow vehicle, comprising the steps of:

a) providing a plurality of metal targets and a trailer having at least two wheels;

b) preparing each said wheel with first attachment means for attaching one said target with said wheel in such manner that said target rotates with said wheel;

c) mounting each said target on one said wheel in such manner as to provide a sensing target rotating with said wheel;

d) providing a plurality of proximity sensors;

e) preparing an axle area adjacent each said wheel with a second attachment means for attaching one said proximity sensor;

f) mounting each said proximity sensor non-rotatably to said trailer in such manner as to sense rotations of one said target past one said proximity sensor and to generate signals directly representing rotational speeds of said wheel;

g) providing a computer structured and arranged so as to receive said signals from each said proximity sensor and to use said signals to compare said representations of rotational speeds of said wheels;

h) mounting said computer on said trailer and coupling said computer to each said proximity sensor; and

i) mounting on said trailer a trailer coupler constructed and arranged to assist in system coupling of said computer to an alarm indicator within a tow vehicle of a type adapted to attach to said trailer.

26. The method of claim 25 further comprising the steps of:

(a) providing a tow vehicle of a type adapted to attach to said trailer;

(b) providing an alarm indicator constructed and arranged for coupling to said computer in such manner as to provide an indication of an abnormal rotational speed of a said wheel; and

(c) mounting said alarm indicator within a cab of said tow vehicle.

27. The method of claim 25 wherein each said proximity sensor is non-rotatably attached to an axle of said trailer.

28. The method of claim 25 wherein each said target comprises a protuberance extending from and rotatably attached with one said wheel.

29. The method of claim 28 wherein each said protuberance is connected to a brake drum of said one wheel.

30. The method of claim 25 wherein said computer does said comparing essentially by counting differences in number of rotations of each said wheel.

31. The method of claim 30 further comprising the step of:

(a) using a programming means for programming said computer for counting rotations of said wheels of said trailer within the same fixed time period in such manner as to provide less sensitivity to rotational-count differences at lower trailer speeds.