Tire pressure warning system
First Claim
Patent Images
1. A tire pressure warning system, comprising:
- a first detector, comprising;
a body portion having a bottom end adapted to mount on a tire valve stem, a top end opposite the bottom end, and an inside and an outside;
a pressure transducer in said body for detecting the pressure in a tire;
an electrical switch actuated by said pressure transducer such that said switch is in a first state at a predetermined low pressure and in a second state at any pressure above a predetermined, higher pressure;
a sensor in said body for sensing whether said switch is in said first or second state;
a transmitter in said body actuated by said sensor when said switch is in said first state for sending a plurlaity of discontinuous, modulated RF signal bursts of a predetermined code sequence through an RF output to indicate a tire pressure below said predetermined pressure;
a counter in said body for counting the number of signal bursts transmitted and disabling the transmitter when a predetermined number of bursts have been transmitted in response to said switch continuing to said first state; and
control means associated with said detector for automatically re-enabling the disabled transmitter and initializing said counter only when said switch is returned to said second state from said first state, whereby said counter disables said transmitter only when the tire pressure is low for a predetermined time period and when the tire pressure changes from low to high pressure, said control means resets said counter and re-enables the disabled transmitter.
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Abstract
A tire pressure warning system, including a valve stem-mounted tire pressure detector, including means for sensing the tire pressure and means for transmitting an encoded signal when the tire pressure drops below a predetermined level, and a receiver that can receive and recognize the encoded signal, differentiate between various encoded signals, and provide a warning signal to the vehicle operator. The inside of the tire pressure detector is hermetically sealed; inside the sealed portion is a unique on/off switch that can be externally actuated without compromising the seal.
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Citations
24 Claims
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1. A tire pressure warning system, comprising:
- a first detector, comprising;
a body portion having a bottom end adapted to mount on a tire valve stem, a top end opposite the bottom end, and an inside and an outside; a pressure transducer in said body for detecting the pressure in a tire; an electrical switch actuated by said pressure transducer such that said switch is in a first state at a predetermined low pressure and in a second state at any pressure above a predetermined, higher pressure; a sensor in said body for sensing whether said switch is in said first or second state; a transmitter in said body actuated by said sensor when said switch is in said first state for sending a plurlaity of discontinuous, modulated RF signal bursts of a predetermined code sequence through an RF output to indicate a tire pressure below said predetermined pressure; a counter in said body for counting the number of signal bursts transmitted and disabling the transmitter when a predetermined number of bursts have been transmitted in response to said switch continuing to said first state; and control means associated with said detector for automatically re-enabling the disabled transmitter and initializing said counter only when said switch is returned to said second state from said first state, whereby said counter disables said transmitter only when the tire pressure is low for a predetermined time period and when the tire pressure changes from low to high pressure, said control means resets said counter and re-enables the disabled transmitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a first detector, comprising;
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10. A tire pressure detector for use on a vehicle, comprising:
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a body portion having an inside, an outside, a bottom end adapted to be coaxilly mounted on the valve stem of a pneumatic tire, and a top end opposite said bottom end; a pressure sensor inside said body for detecting the pressure inside a tire; a transmitter inside the body connected to said pressure sensor for transmitting a signal when the tire pressure drops below a predetermined level; a power supply inside the body; a power switch inside the body for supplying power from the power supply to the transmitter whether or not said sensor is mounted on the valve stem; means for sealing the inside of the body from the outside of the body; and means on the outside of the body for actuating the power switch without comprising the seal, said actuating means being capable of actuating the power switch whether or not said vehicle is moving and independent of the level of said tire pressure. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A tire pressure warning system, comprising:
a tire pressure monitoring device comprising a housing, a battery inside the housing, an opening in the housing, means to monitor the pressure of air in the opening, means to attach the device to a tire to place the opening in fluid connection with the interior of the tire, means to transmit a plurality of first signals when the pressure in the opening is below a predetermined level, means for counting the number of first signals transmitted, means for disabling the transmitting means when the number of signals transmitted in response to a continuing low pressure in the opening equals a predetermined number, and means for re-enabling the disabled transmitting means and initializing the counting means when the pressure in the opening subsequently exceeds the predetermined level. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A tire pressure system, comprising:
- a detector, comprising;
a body portion having a bottom end adapted to mount on a tire valve stem, a top end, and an inside and an outside; a pressure transducer in said body for detecting the pressure in a tire; an electric switch actuated by said pressure transducer such that said switch is in said first state at a predetermined low pressure and in a second state at any pressure above a predetermined, higher pressure; a sensor in said body for sensing whether said switch is in said first or second state; a transmitter in said body actuated by said sensor when said switch is in said first state for sending an RF signal through an RF output to indicate a tire pressure below said predetermined pressure; a first seal in the bottom end of said body for isolating the transmitter from the pressure in a tire when the device is mounted on a valve stem; a second seal in the top end of said body for isolating the transmitter from the atmosphere; and means for supplying power to the said detector by deforming said second seal.
- a detector, comprising;
Specification