Warning device for tire pressure anomalies

• US 4,090,172 A
• Filed: 08/04/1975
• Issued: 05/16/1978
• Est. Priority Date: 08/04/1975
• Status: Expired due to Term

• Current Assignee: Borislav Vesnic
• Original Assignee: Borislav Vesnic
• Inventors: Vesnic, Borislav
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Nowicki, Joseph E.
• Application Number:
  US05/601,523
• Time in Patent Office: 1,016 Days
• Field of Search: 340/58, 200/61.22, 200/61.25, 200/61.26, 73/146.3, 73/146.5, 73/146.8, 325/113, 325/117, 179/2, 343/712, 343/711, 343/713, 343/878
• US Class Current: 340/448
• CPC Class Codes: B60C 23/0428 using passive wheel mounted resonance circuits
• CPC Class Codes: B60C 23/0447 Wheel or tyre mounted circuits

Abstract

A warning device for tire pressure anomalies in which the valve of the tire to be monitored is connected to a pressure variation sensor which has two pressure thresholds, one for insufficient pressure, the other for excess pressure. When one of the thresholds is reached, the sensor closes an alarm circuit connected to an electronic signalling circuit on a printed circuit fixed on a sealed casing that is rigidly connected to the frame of the wheel and which contains two batteries that supply the signal transmission circuit. The data delivered by the signalling circuit is sensed by a detector that supplies a series of frequency selectors that discriminate the tire for which a warning is given for excess or low pressure. In the case of a pressure anomaly, the frequency severally command a relay that energizes a signal light and triggers an acoustic signal.

Claims

1. A device for providing a warning signal when the inflation pressure of a respective vehicle tire mounted on a metallic frame falls out of a predetermined range, comprising a plurality of signalling circuits each adapted to be mounted to a respective wheel to which an inflated tire is mounted, each signalling circuit including a tire pressure sensor adapted to be mounted to the wheel and generate an output signal, oscillating circuit means adapted to be mounted to the wheel responsive to the output signal of said sensor for producing an oscillating signal in the form of a wave, and means for inductively transmitting said oscillating signal via the respective wheel to said metallic frame, the oscillating signal produced by each oscillating circuit means being at a different predetermined frequency;

pick-up means including a plurality of tuned receiver means adapted to be mounted on the frame for detecting respectively the oscillating signals produced by each of said oscillating circuit means and generate an output signal responsive thereto; and

a plurality of indicator means adapted to be mounted in the vehicle responsive to the output signal of said pick-up means for indicating tire pressure conditions in the respective tires.

2. The device of claim 1 wherein each said sensor means includes means for producing a first signal indicating that the pressure is above an acceptable range and a second signal indicating that the pressure is below an acceptable range, each of said oscillating circuit means including means for producing a corresponding fixed frequency oscillating signal at different first and second fixed frequencies corresponding to said first and second signals from said sensor means, said pick-up means including tuned receivers corresponding to each of said first and second fixed frequencies produced by each of said circuit means, said indicator means including means for indicating which tire has an unacceptable inflation pressure and whether said inflation pressure is above or below the acceptable range.

3. The device of claim 1 wherein each said signalling circuit includes means for producing a carrier frequency signal, and means for modulating said carrier frequency signal with said oscillating signal.

4. The device of claim 3 wherein the carrier frequency signals produced by said signalling circuits are at the same frequency.

5. An alarm system for providing a signal when the inflation pressure of an inflated tire mounted on a metallic vehicle frame falls out of a predetermined range, comprising:

signal generating means for sensing and emitting a signal in the form of a wave when the inflation pressure falls above or below a predetermined range,

said signal generating means including a source of D.C. power,

transmission means for transmitting the signal to said metallic frame,

receiving means for receiving the signal from the frame, and

converting means for converting the signal into a discernable alarm.

6. The system of claim 5, wherein a plurality of inflated tires are provided, and further including a separate signal generating means associated with each tire.

7. The system in claim 6, wherein the signal generating means for each tire emits a signal at a frequency different from that for the other tires, said receiving means including means for distinguishing among the different frequencies, said converting means providing a different discernable alarm for each frequency.

8. The system in claim 5, wherein the signal generating means includes means for emitting a different signal depending on whether the tire has too much pressure or insufficient pressure.

9. The system in claim 8, wherein the different signals have different frequencies.

10. The system in claim 5, wherein the receiving means includes an induction coil in contact with the frame.

11. The system in claim 5, wherein the signal generating means includes adjustment means for varying the range above and below which the inflation pressure is sensed and the signal emitted.

12. The system in claim 11, wherein the adjustment means includes a housing, two conductive pins projecting into the housing into the path of a piston, said piston being adapted to move in the housing in response to pressure changes in the tire, one of the pins positioned to contact the piston when the tire is overinflated and the other pin positioned to contact the piston when the tire is underinflated, means for moving the pins relative to the piston for varying said range.