TIRE CONDITION MONITORING SYSTEM

• US 3,602,884 A
• Filed: 02/11/1970
• Issued: 08/31/1971
• Est. Priority Date: 02/11/1970
• Status: Expired due to Term

• Current Assignee: Joseph S. Brumbelow
• Original Assignee: Joseph S. Brumbelow
• Inventors: Brumbelow, Joseph S.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/010,414
• Time in Patent Office: 566 Days
• Field of Search: 340/58 200/61.22,61.25,61.26
• US Class Current: 340/448
• CPC Class Codes: B60C 23/0427 Near field transmission with inductive or capacitive coupling means
• CPC Class Codes: B60C 23/0428 using passive wheel mounted resonance circuits

Abstract

A tire monitoring system for a motor vehicle employs a wheel mounted unit which is physically unattached to the remainder of the system. A primary unit of the system is situated to be inductively coupled to the wheel unit. The inductive coupling is intermittent inasmuch as the wheel unit is adjacent to the primary unit during only a part of the wheel'"'"''"'"'s rotation. The wheel unit uses a sensor to monitor the tire pressure or temperature and the sensor, in response to an unsafe condition of the tire, causes an alteration in the amount of energy coupled by induction to the wheel unit. The change in energy is detected by comparing the energy delivered to the inductively coupled element in the primary unit with the energy delivered to a '"'"''"'"''"'"''"'"'standard'"'"''"'"''"'"''"'"' element which is not affected by the inductive coupling. The detected change in inductively coupled energy is amplified and the amplified signal is employed to actuate an alarm.

Claims

1. A system for detecting the unsafe condition of a motor vehicle tire, the system comprising a first inductor mounted to rotate with the tire;

a second inductor situated to inductively couple to the first inductor;

means for electrically energizing the second inductor;

comparator means for comparing the electrical energy applied to the second inductor with the electrical energy applied to a standard inductor;

a tire condition sensor mounted to rotate with the tire, the sensor responding to an unsafe condition of the tire by altering the amount of electrical energy coupled by induction from the second inductor to the first inductor; and

means responsive to the comparator means for actuating an alarm upon the occurrence of a substantial alteration in the amount of inductively coupled energy.

2. The system according to claim 1, wherein the tire condition sensor is a core of ferromagnetic material whose Curie point is at a temperature that is unsafe for the tire, and the first inductor is a coil disposed upon the core of ferromagnetic material.

3. The system according to claim 1, wherein the second inductor is an element of a resonant primary circuit;

the first inductor is an element of a secondary circuit capable of resonating at the same frequency as the primary circuit; and

the tire condition sensor permits the secondary circuit to resonate upon the occurrence of an unsafe condition of the tire.

4. A monitor system for detecting the unsafe condition of a motor vehicle tire, the system comprising a stationary unit having a first resonant circuit utilizing a primary inductor;

a source of electrical energy coupled to the first resonant circuit to cause the circuit to resonate;

a standard resonator;

comparator means for comparing the energy in the first resonant circuit with the energy in the standard resonator;

a second resonant circuit mounted to rotate with the tire, the second resonant circuit utilizing a secondary inductor and the circuit being capable of resonating at the same frequency as the first resonant circuit;

the stationary unit being mounted on the vehicle in a position where the primary inductor inductively couples to the secondary inductor during a portion of the tire'"'"''"'"'s revolution;

a tire condition sensor mounted to rotate with the tire, the sensor responding to an unsafe tire condition by enabling the secondary circuit to resonate; and

means responsive to the comparator for actuating an alarm upon the intermittent occurrence of an appreciable change in energy in the first resonant circuit.