Tire pressure monitoring device

• US 6,629,454 B2
• Filed: 11/21/2001
• Issued: 10/07/2003
• Est. Priority Date: 11/21/2000
• Status: Expired due to Fees

• Current Assignee: Torbjörn Boson Lundqvist
• Original Assignee: Torbjörn Boson Lundqvist
• Inventors: Lundqvist, Torbjörn Boson
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US09/990,234
• Publication Number:
  US 20020059825A1
• Time in Patent Office: 685 Days
• Field of Search: 731/46, 731/462, 731/463, 731/464, 731/465, 731/468, 340/447, 340/442
• US Class Current: 73/146.8
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0496 Valve stem attachments positioned outside of the tyre chamber

Abstract

A low tire pressure monitoring device that is affixed to a tire valve stem and methods of using the same. The monitoring device comprises a housing having a counter-pressure chamber, a main pressure chamber, and a flexible membrane that separates the two chambers. The monitoring device is calibrated by trapping the tire'"'"'s initial air pressure in the counter-pressure chamber. The air pressure within the main pressure chamber is equivalent to the air pressure within the tire. Over the course of time, the air pressure within the tire and concomitantly the air pressure within the main pressure chamber decreases. When the pressure in the counter-pressure is greater than the pressure within the main pressure chamber, the flexible membrane touches and completes an electrical circuit and a warning signal is emitted.

Claims

1. A tire pressure monitoring device for monitoring tire pressure, said monitoring device comprising:

a housing having a first pressure chamber, a second pressure chamber; and

a flexible membrane, wherein said first and second pressure chambers are separated by a flexible membrane, wherein the first pressure chamber is calibrated with air from a tire; and

a signaling means for emitting a warning signal when a pressure within the first pressure chamber is greater than a pressure within the second pressure chamber;

wherein the housing is adapted to be mounted onto a tire stem.

said housing having a first pressure chamber, a second pressure chamber, and a flexible membrane, wherein said first and second pressure chambers are separated by a flexible membrane; and

a signaling means located within said housing, wherein said signaling means emits a warning signal when a pressure within the first pressure chamber is greater than a pressure within the second pressure chamber.

2. The tire pressure monitoring device of claim 1 wherein said housing further comprises:

a lens, a main housing, and a lower housing, wherein said lens is coupled to a first end of said main housing and said lower housing is coupled to a second end of said main housing.

3. The tire pressure monitoring device of claim 2 further comprising a screw cap that couples said lens to said main housing.

4. The tire pressure monitoring device of claim 3 further including a conductive gasket provided between said lens and said main body.

5. The tire pressure monitoring device of claim 1 wherein said housing further includes at least one battery.

6. The tire pressure monitoring device of claim 1 wherein said flexible membrane is a conductive substance.

7. The tire pressure monitoring device of claim 6 wherein said conductive substance is a conductive metal or conductive rubber.

8. The tire pressure monitoring device of claim 1 wherein said signaling means is coupled to a printed circuit board.

9. The tire pressure monitoring device of claim 1 wherein said signaling means is selected from the group consisting of a light emitting diode (LED), a speaker, a radio frequency (RF) transmitter, and a infrared (IR) transmitter.

10. The tire pressure monitoring device of claim 1 further including a conductive seal provided between said lens and said main body.

11. The tire pressure monitoring device of claim 1 wherein said power supply is at least one battery.

12. The tire pressure monitoring device of claim 1 wherein said signaling means is selected from the group consisting of a light emitting diode (LED), a speaker, a radio frequency (RF) transmitter, and a infrared (IR) transmitter.

13. The tire pressure monitoring device of claim 1 wherein said flexible membrane is a conductive substance.

14. A method of monitoring air pressure within a tire, said method comprising:

providing a tire pressure monitoring device of claim 1;

attaching said tire pressure monitoring device to a tire valve;

calibrating said tire pressure monitoring device with air pressure from the tire;

monitoring a pressure differential between said tire pressure monitoring device and an air pressure of said tire; and

emitting a warning signal when said pressure differential exceeds a predetermined pressure differential.

15. The method of claim 14 wherein said calibrating step further includes allowing air from said tire to enter a counter-pressure chamber of said tire pressure monitoring device and sealing said counter-pressure chamber.

16. The method of claim 15 wherein said pressure differential is a difference between the pressure of said counter-pressure chamber and said air pressure of said tire.

17. The method of claim 16 wherein said warning signal comprises a signal selected from the group consisting of a light, a sound, a radio frequency (RF) wave, and an infrared (IR) light.

18. A method of monitoring air pressure within a tire, said method comprising:

providing a tire pressure monitoring device of claim 1;

attaching said tire pressure monitoring device to a tire valve;

calibrating said tire pressure monitoring device;

monitoring a pressure differential between said tire pressure monitoring device and an air pressure of said tire; and

emitting a warning signal when said pressure differential exceeds a predetermined pressure differential.

19. The method of claim 14 further comprising:

removing said tire pressure monitoring device from said tire valve;

adding air pressure to said tire; and

reattaching said tire pressure monitoring device to said tire valve.

20. The tire pressure monitoring device of claim 1 wherein said housing includes threads for mounting said tire pressure monitoring device onto a tire system.

21. The tire pressure monitoring device of claim 1 wherein said lower housing body includes threads for mounting said tire pressure monitoring device onto the tire valve.

22. A valve cap having an interior air pressure supplied through a conventional tire valve, said valve cap comprising:

a transparent top;

a light emitting diode (LED) attached to a printed circuit board;

an upper housing coupled to a lower housing, the upper housing which accommodates the LED, the printed circuit board, and a flexible membrane;

a counter-pressure chamber, wherein the counter-pressure chamber is a space between the transparent top and the flexible membrane;

a main pressure chamber, wherein the main pressure chamber is a space between the flexible membrane and the lower housing,

the counter-pressure chamber having a first open mode wherein the counter-pressure chamber is in atmospheric communication with the main pressure chamber, and the counter-pressure chamber having a second closed mode wherein the counter-pressure chamber is sealed from the main pressure chamber;

at least one battery located within the upper housing; and

the lower housing which is internally threaded to mate with a tire valve assembly.

23. A valve cap as defined in claim 22, wherein the circuit board further comprises flashing circuitry.

24. A tire pressure monitoring device for monitoring tire pressure, said monitoring device comprising:

a housing having a first pressure chamber in communication with a second pressure chamber, wherein the first pressure chamber having a first open mode wherein the first pressure chamber is in atmospheric communication with the second pressure chamber, and the first pressure chamber having a second closed mode wherein the first pressure chamber is sealed from the second pressure chamber; and

a flexible membrane positioned between the first pressure chamber and the second pressure chamber.

25. A tire pressure monitoring device comprising:

means for mounting the device onto a tire stem;

means for calibrating the device to air pressure in the tire at an initial point in time with air from within the tire;

means for indicating at a subsequent point in time that air pressure in the tire has decreased beyond a pre-determined pressure difference, as compared to the pressure in the tire at said initial point in time.

26. A tire pressure monitoring device comprising:

a housing having a first pressure chamber in communication with a second pressure chamber, wherein the first pressure chamber having a first open mode wherein the first pressure chamber is in atmospheric communication with the second pressure chamber, and the first pressure chamber having a second closed mode wherein the first pressure chamber is sealed from the second pressure chamber; and

a flexible membrane positioned between the first pressure chamber and the second pressure chamber; and

a signaling means for emitting a warning signal when a pressure within the first pressure chamber is greater than a pressure within the second pressure chamber;

wherein the housing is adapted to be mounted onto a tire stem.

27. A tire pressure monitoring device attachable to a tire valve for monitoring tire pressure, said tire pressure monitoring device comprising:

a housing including a means for calibrating said pressure monitoring device with air from a tire, a means for sensing a pressure differential, and a means for signaling said pressure differential.