Tire inflation monitoring system
First Claim
1. A system for monitoring the inflation of a tire mounted on the wheel of a vehicle comprising a sensor circuit mounted to rotate with said vehicle wheel and an alarm circuit associated with the vehicle body, said sensor circuit including an inductor coil means wound on a powder core and mounted to rotate with said vehicle wheel and a pressure switch responsive to a change in pressure within said tire from an acceptable pressure to an unacceptable pressure, said pressure switch being in serial electrical connection with said inductor coil means, said alarm circuit including in electrical connection an inductor coil means wound on a powder core, capacitance means, resistor means, oscillator means for generating an alternating current signal of constant frequency and an alarm triggering circuit responsive to a change in the voltage pattern across said second-mentioned inductor coil means occurring when said pressure switch responds to a change in pressure within said tire from an acceptable pressure to an unacceptable pressure, said sensor circuit exhibiting an effective distributed capacitance characteristic at the frequency of the signal generated by said oscillator means with said pressure switch in an open condition and said first-mentioned inductor coil being in relatively close proximity to said second-mentioned inductor coil, said second-mentioned inductor coil means being mounted to said vehicle body at a position so that said first-mentioned inductor coil means mounted with said vehicle wheel passes in close proximity to said second-mentioned inductor coil means during each rotation of said vehicle wheel, said second-mentioned inductor coil means and said capacitance means of said alarm circuit being in a "primary circuit" that is in electrical resonance at the frequency of the signal generated by said oscillator means, said first-mentioned inductor coil means containing a number of turns of wire in the coil to cause said first-mentioned inductor coil means to be in electrical resonance with its said effective distributed capacitance at the frequency of the signal generated by said oscillator means with said pressure switch in the open position and during the time said first-mentioned inductor coil means passes in close proximity to said second-mentioned inductor coil means and to cause the circuit that includes said first-mentioned inductor coil means and said switch means to be in matched resonance with the said "primary circuit" of said alarm circuit when said pressure switch is in the open position and during the time said first-mentioned inductor coil means passes in close proximity to said second-mentioned inductor coil means.
8 Assignments
0 Petitions
Accused Products
Abstract
A monitoring system for motor vehicles that produces a warning signal when the pressure within a tire changes to an unacceptable pressure. The system includes a sensor unit attached on the wheel on which the tire to be monitored is mounted and a second component secured to the vehicle body. The unit mounted to the vehicle body contains a coil wound on a core that is positioned at a location so that as the wheel of the vehicle revolves a second coil wound on a core that forms a part of the sensor unit comes into close proximity to the coil secured to the vehicle body during each rotation of the wheel. When the pressure in the tire changes from a "normal" pressure, a harmonious balance between the two components of the system is disturbed resulting in the triggering of a warning mechanism that alerts the operator of the vehicle that the air pressure in the tire has reached an unacceptable level.
27 Citations
9 Claims
- 1. A system for monitoring the inflation of a tire mounted on the wheel of a vehicle comprising a sensor circuit mounted to rotate with said vehicle wheel and an alarm circuit associated with the vehicle body, said sensor circuit including an inductor coil means wound on a powder core and mounted to rotate with said vehicle wheel and a pressure switch responsive to a change in pressure within said tire from an acceptable pressure to an unacceptable pressure, said pressure switch being in serial electrical connection with said inductor coil means, said alarm circuit including in electrical connection an inductor coil means wound on a powder core, capacitance means, resistor means, oscillator means for generating an alternating current signal of constant frequency and an alarm triggering circuit responsive to a change in the voltage pattern across said second-mentioned inductor coil means occurring when said pressure switch responds to a change in pressure within said tire from an acceptable pressure to an unacceptable pressure, said sensor circuit exhibiting an effective distributed capacitance characteristic at the frequency of the signal generated by said oscillator means with said pressure switch in an open condition and said first-mentioned inductor coil being in relatively close proximity to said second-mentioned inductor coil, said second-mentioned inductor coil means being mounted to said vehicle body at a position so that said first-mentioned inductor coil means mounted with said vehicle wheel passes in close proximity to said second-mentioned inductor coil means during each rotation of said vehicle wheel, said second-mentioned inductor coil means and said capacitance means of said alarm circuit being in a "primary circuit" that is in electrical resonance at the frequency of the signal generated by said oscillator means, said first-mentioned inductor coil means containing a number of turns of wire in the coil to cause said first-mentioned inductor coil means to be in electrical resonance with its said effective distributed capacitance at the frequency of the signal generated by said oscillator means with said pressure switch in the open position and during the time said first-mentioned inductor coil means passes in close proximity to said second-mentioned inductor coil means and to cause the circuit that includes said first-mentioned inductor coil means and said switch means to be in matched resonance with the said "primary circuit" of said alarm circuit when said pressure switch is in the open position and during the time said first-mentioned inductor coil means passes in close proximity to said second-mentioned inductor coil means.
Specification