Tire pressure indicator
First Claim
1. A system for electro-magnetically monitoring the internal pressure of a tire having a plurality of possible states comprising:
- a. pressure sensor means for determining one of the said plurality of states of said tire;
b. transmitter means for transmitting an interrogation signal composed of a carrier wave modulated at a predetermined modulating frequency and means tuned to said carrier frequency to remove all residual energy at the modulating frequency;
c. transponder means, operable in response to said pressure sensor means, for passively detecting said interrogation signal and retransmitting an information signal at said modulating frequency as a function of the state of said sensor, said transponder means comprising a non-linear electrical element series coupled to an inductor;
d. and receiver means comprising a parallel coupled inductor and capacitor tuned only to said modulating frequency for providing an output indicative of the tire pressure.
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Accused Products
Abstract
An improved system is disclosed for electro-magnetically monitoring the condition of a vehicle tire which has a plurality of possible states, such as an internal air pressure which can fall within predetermined limits. The system is of the type which comprises a transmitter which serves to transmit to the monitored vehicle tire an interrogation signal composed of a carrier wave modulated at a predetermined modulating frequency. The tire to be monitored carries a transponder device which is operable in response to the state of the tire for passively detecting the modulating frequency of the interrogation signal and retransmitting an information signal at the modulating frequency. A receiver is provided responsive to the retransmitted information signal so as to provide an output which is indicative of the state of the device being monitored.
The transponder includes an improved signal coil, embedded within the body of the vehicle tire and disposed as a circular loop about the tire, coaxial with the axis of rotation thereof. This improved coil configuration enables a continuous and more uniform display of the condition of the tire when the vehicle is in motion.
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Citations
11 Claims
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1. A system for electro-magnetically monitoring the internal pressure of a tire having a plurality of possible states comprising:
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a. pressure sensor means for determining one of the said plurality of states of said tire; b. transmitter means for transmitting an interrogation signal composed of a carrier wave modulated at a predetermined modulating frequency and means tuned to said carrier frequency to remove all residual energy at the modulating frequency; c. transponder means, operable in response to said pressure sensor means, for passively detecting said interrogation signal and retransmitting an information signal at said modulating frequency as a function of the state of said sensor, said transponder means comprising a non-linear electrical element series coupled to an inductor; d. and receiver means comprising a parallel coupled inductor and capacitor tuned only to said modulating frequency for providing an output indicative of the tire pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification