System for transmitting information of reduced pneumatic pressure of tire

• US 3,895,347 A
• Filed: 07/25/1974
• Issued: 07/15/1975
• Est. Priority Date: 09/10/1973
• Status: Expired due to Term

• Current Assignee: Akira Fujikawa, Akira Matsuda, George Matsuura, Hideo Togawa, Kenzo Nakanishi, Takashi Takusagawa, Yasuaki Hanasaka
• Original Assignee: Akira Fujikawa, Akira Matsuda, George Matsuura, Hideo Togawa, Kenzo Nakanishi, Takashi Takusagawa, Yasuaki Hanasaka
• Inventors: Matsuda, Akira, Takusagawa, Takashi, Fujikawa, Akira, Matsuura, George, Nakanishi, Kenzo, Togawa, Hideo, Hanasaka, Yasuaki
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/491,902
• Time in Patent Office: 355 Days
• Field of Search: 340/58 200/61.22,61.25
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0428 using passive wheel mounted resonance circuits
• CPC Class Codes: G01L 11/00 Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
• CPC Class Codes: G01L 17/00 Devices or apparatus for measuring tyre pressure or the pressure in other inflated bodies

Abstract

A system for transmitting information of reduced pneumatic pressure of tires comprising an electromagnetic wave radiation mechanism of an electric field excitation system and at least one receiver antenna of an electromagnetic field sensing type for sensing a polarized wave of an electromagnetic field radiated from the radiation mechanism. The radiation mechanism includes an electromagnetic wave radiation member consisting of a substantially concentric metal body opposedly and substantially provided on each axle of a plurality of tire wheels for actuating as an electric dipole together with the wheels and an oscillator electrically coupled to the radiation member and energized by a switch actuated in response to reduced pneumatic pressure of tire. The receiver antenna is provided in the space between the ground surface and the lower surface of the bottom plate of the car body in order to screen external noise waves.

Claims

1. A system for transmitting information of reduced pneumatic pressure of tires, comprising an electromagnetic wave radiation mechanism of an electric field excitation system having an electromagnetic wave radiation member consisting of a substantially concentric metal body opposedly and substantially concentrically provided on each axle of a plurality of tire wheels for actuating as an electric dipole together with the wheels and having an oscillator electrically coupled to said radiation member and energized in response to reduced pneumatic pressure of tires;

and at least one receiver antenna of an electromagnetic field sensing type provided in the space between the surface of the ground and the lower surface of the bottom plate of the car body for sensing a polarized wave of an electromagnetic field radiated from said radiation mechanism in order to screen external noise waves.

2. The system as claimed in claim 1, wherein said electromagnetic wave radiation body consists of a metal ring having a common axis to metal wheel for holding the tire, said metal ring is electrically insulated and opposedly arranged to said metal wheel, and is used as a radiation antenna for the output of an oscillator energized in response to reduced pneumatic pressure of the tire.

3. The system as claimed in claim 1, wherein said metal ring is formed into the shape of an open ring with a cutout portion, whereby the electromagnetic wave having a standing wave generated in the form of the metal ring is radiated.

4. The system as claimed in claim 2, wherein said metal ring is embedded in an annular insulating body made of a material selected from hard plastic materials, hard rubbers or the like, and said insulating body is fitted to a rim of the wheel.

5. The system as claimed in claim 1, further including a loop-shaped projected member positioned inwards in the radial direction from the rim portion of the wheel and substantially concentrically projected in the direction of the axle of the wheel, said projected member being integrally formed with the wheel, and an electromagnetic radiation member consisting of a loop-shaped metal body being provided in opposition to said projected member.

6. The system as claimed in claim 4, wherein the oscillator and a power supply source thereof are embedded in said annular insulating body.

7. The system as claimed in claim 4, wherein the annular insulating body is detachably fitted to the rim of the wheel by means of a jig along the inner surface in the radial direction thereof.

8. The system as claimed in claim 7, wherein the power supply source embedded in the annular isulating body is small mercury dry cell.

9. The system as claimed in claim 1, wherein said receiver antenna is an aNtenna of an electric field sensing type for sensing a horizontally polarized wave of an electric field radiated from said electromagnetic wave radiation mechanism.

10. The system as claimed in claim 1, wherein said receiver antenna is an antenna of a magnetic field sensing type for sensing a vertically polarized wave of a magnetic field radiated from said electromagnetic wave radiation mechanism.

11. The system as claimed in claim 10, wherein said antenna of magnetic field sensing type is consisted of a bar-shaped magnetic core, a sense winding wound around said magnetic core, and an electrostatic shielding cylinder provided around said winding, and the axis of said magnetic core is coinsided with a perpendicular dropped from the bottom surface of the car body onto the surface of the ground.

12. The system as claimed in claim 1, wherein the receiver antenna is a bar-shaped receiver antenna, and said antenna is substantially arranged along the axle direction of the car body.

13. The system as claimed in claim 12, wherein the bar-shaped receiver antenna is substantially arranged along the forward direction of the car body.

14. The system as claimed in claim 1, wherein use is made of two rod-shaped receiver antennas, and said antennas are so arranged that its axes are intersected each other.

15. The system as claimed in claim 1, wherein the substantial center of at least one receiver antenna is arranged at an intersection of diagonal lines from four wheels of a four-wheel vehicle.