Tire air pressure monitoring device using the wheel or a coil wound around the stem as the transmitter antenna
First Claim
1. An air pressure monitoring device comprising a valve stem, through which air is charged, arranged to extend through a vehicle wheel, and a transmitter secured to the wheel to transmit a signal representing the air pressure of the wheel to a receiver installed in the vehicle, wherein the valve stem includes a threaded section, wherein the monitoring device further comprises:
- a case attached to the wheel, the case being connected to the valve stem;
an electric circuit accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal;
an antenna, which radiates the signal produced by the electric circuit, arranged about the valve stem, and wherein the antenna includes;
a nut fastened to the threaded section;
a coil wound about the valve stem; and
an insulating material for covering the coil and securing the coil to the nut; and
a means for conveying the signals produced by the electric circuit to the antenna.
1 Assignment
0 Petitions
Accused Products
Abstract
A device for monitoring the air pressure of a wheel. The device prevents a decrease in the transmission level of radio waves caused by impedance mismatch between an antenna, which radiates the radio waves, and a circuit, which produces signals that are to be radiated as the radio waves. The device includes a valve stem through which air is charged. The valve stem extends through a vehicle wheel. A transmitter is secured to the wheel to transmit a signal representing the air pressure of the wheel to a receiver installed in the vehicle. The device further includes a case attached to the wheel. The case is connected to the valve stem. An electric circuit is accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal. An antenna radiates the signal produced by the electric circuit and is arranged about the valve stem. A conveying mechanism conveys the signals produced by the electric circuit to the antenna.
60 Citations
17 Claims
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1. An air pressure monitoring device comprising a valve stem, through which air is charged, arranged to extend through a vehicle wheel, and a transmitter secured to the wheel to transmit a signal representing the air pressure of the wheel to a receiver installed in the vehicle, wherein the valve stem includes a threaded section, wherein the monitoring device further comprises:
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a case attached to the wheel, the case being connected to the valve stem; an electric circuit accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal; an antenna, which radiates the signal produced by the electric circuit, arranged about the valve stem, and wherein the antenna includes; a nut fastened to the threaded section; a coil wound about the valve stem; and an insulating material for covering the coil and securing the coil to the nut; and a means for conveying the signals produced by the electric circuit to the antenna. - View Dependent Claims (2, 3, 4, 5)
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6. An air pressure monitoring device comprising a valve stem, through which air is charged, arranged to extend through a vehicle wheel, a transmitter secured to the wheel to transmit a signal representing the air pressure of the wheel to a receiver installed in the vehicle, wherein the monitoring device further comprises:
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a case attached to the wheel, the case being connected to the valve stem; an electric circuit accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal; a coiled antenna for radiating the signal produced by the electric circuit, the antenna being wound about the valve stem; and a means for conveying the signals produced by the electric circuit to the antenna. - View Dependent Claims (7, 8)
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9. An air pressure monitoring device comprising a valve stem, through which air is charged, arranged to extend through a vehicle wheel, a transmitter secured to the wheel to transmit a signal representing the air pressure of the wheel to a receiver installed in the vehicle, wherein the monitoring device further comprises:
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a case attached to the wheel, the case being connected to the valve stem; an electric circuit accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal; and a conveying means for conveying the signals produced by the electric circuit to the valve stem and the wheel, wherein the valve stem and the wheel are electrically conductive and are used as an antenna that radiates the signal. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A transmitter for transmitting a signal representing the air pressure of a wheel to a receiver installed in a vehicle, the transmitter being secured to the wheel, wherein the transmitter comprises;
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a case attached to the wheel; an electric circuit accommodated in the case to detect the air pressure and convert the detected pressure to an electric signal; and a means for conveying the signals produced by the electric circuit to the wheel, wherein the wheel is used as an antenna that radiates the signal. - View Dependent Claims (16, 17)
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Specification