United States Patent [191
`Nowicki et al.
`
`U 5005285189A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,285,189
`Feb. 8, 1994
`
`[54] ABNORMAL TIRE CONDITION WARNING
`SYSTEM
`[75] Inventors: Donald V. Nowicki, Lorain;
`Christopher A. Munroe, Norwalk,
`both of Ohio
`[73] Assignee: Epic Technologies, Inc., Norwalk,
`Ohio
`[21] App]. No.: 699,758
`[22] Filed:
`May 14, 1991
`
`V
`
`[56]
`
`'
`
`.
`
`[51] Int. Cl.5 ....................................... .. B60C 23/00
`[52] US. Cl. ................................. .. 340/447; 73/ 146.5;
`ZOO/61.22; 340/442
`[58] Field of Search ............. .. 340/447, 445, 442, 438;
`' 73/ 146.5; 116/34 R; ZOO/61.22; 455/99
`References Cited
`U.S. PATENT DOCUMENTS
`3,938,077 2/1976 Nakanishi et a1. .
`3,950,726 4/ 1976 Fujikawa et a1. .
`4,048,614 9/1977 Shumway .
`4,075,603 2/1978 Snyder et 11.1.
`4,090,172 5/1978 Vesnic .
`4,117,452 9/1978 Snyder et al. .
`4,131,877 12/1978 Stewart et a1. .................... .. 340/445
`4,160,234 7/1979 Karbo et a]. .
`4,210,898 7/1980 Betts.
`4,237,728 12/1980 Betts et al. .
`‘4,286,253 8/1981 Nagy.
`4,311,985 l/1982 Gee et al. .......................... .. 340/447
`4,384,482 5/1983 Snyder.
`4,455,682 6/1984 Masters .
`4,507,956 4/1985 Schlesinger et a]. .
`4,510,484 4/1985 Snyder.
`4,511,869 4/1985 Snyder et a1. .
`4,531,112 7/1985 Thomas ............................. .. 340/447
`
`4,695,823 9/1987 Vernon ............................. .. 940/441
`4,909,074 3/1990 Gerresheim et a1.
`340/445
`4,970,491 11/1990 Saint m1. ............ .. 340/441
`
`5,001,457 3/1991 Wang . . . . . . . . . . . . .
`
`. . . .. 340/447
`
`340/447
`5,061,917 10/1991 Higgs et 11.
`5,109,213 4/1992 Williams ............................ ..340/447
`Primary Examiner-Brent Swarthout
`Attorney, Agent, or Finn-Fay, Sharpe, Beall, Fagan,
`Minnich & McKee
`
`ABSTRACT
`-
`[57]
`A device is provided for sensing the condition of a
`pneumatic tire preferably of the type used on an auto
`mobile wherein the tire is mounted on a tire rim. The
`device comprises a housing, a band for mounting the
`’ housing to the tire rim, a sensor for monitoring the
`condition within the tire, circuitry operatively con
`nected to the sensor for generating radio signals indica
`tive of the tire condition, a power supply operatively
`connected to the circuitry, a centrifugal switch, and a
`receiver for receiving the radio signals. The centrifugal
`switch may be bypassed with the condition sensor
`switch to generate the radio signals when the pneumatic
`tire is stationary. Otherwise, the circuitry within the
`housing remains disabled until such time as the centrifu
`gal switch senses a rotational frequency above a prede
`termined level. The circuitry is provided with a mi
`crocontroller operable between an active and a low
`power consumption mode wherein the battery compris
`ing the power supply is conserved. A watchdog ar
`rangement between the radio receiver and transmitter
`provides for a self-checking feature to alert an operator
`of the automobile of possible fault conditions such as
`low battery or circuit malfunction.
`
`10 Claims, 4 Drawing Sheets
`
`3011
`
`CENTRIFICAL
`
`2|\
`PRESSURE
`TRANSDUCER
`
`MICRO.
`
`I
`l
`CONTROLLER L
`
`|':3 ?|
`J
`
`(1001 g VNNELLNV :
`
`O “I
`
`v
`
`SCHRADER
`EXH. 1005
`Page 1005-1
`
`

`

`US. Patent
`
`Feb. 8, 1994
`
`Sheet 1 of 4
`
`5,285,189
`
`RADIO
`‘ RECEIVER
`
`5% =E= _
`
`J.
`
`SCHRADER
`EXH. 1005
`Page 1005-2
`
`

`

`US. Patent
`
`Feb. 8, 1994
`
`Sheet 2 of 4
`
`5,285,189
`
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`SCH RADER
`
`EXH.' 1005
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`Page 1005-3
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`SCHRADER
`EXH. 1005
`Page 1005-3
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`

`

`US. Patent
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`EXH. 1005
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`Page 1005-4
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`SCHRADER
`EXH. 1005
`Page 1005-4
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`
`

`

`US. Patent
`
`Feb. 8, 1994
`
`Sheet 4 of 4
`
`5,285,189
`
`ANTENNA
`LOOP
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`‘ EXH. 1005
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`Page 1005-5
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`SCHRADER
`EXH. 1005
`Page 1005-5
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`

`

`1
`
`ABNORMAL TIRE CONDITION WARNING
`SYSTEM
`
`5,285,189
`2
`placement is very expensive when considering tire dis- _
`mounting/mounting, wheel balancing, and the cost of
`the replacement batteries themselves.
`
`5
`
`25
`
`BACKGROUND OF THE INVENTION
`This invention relates to the art of abnormal tire con
`dition warning systems and particularly to battery pow
`ered systems.
`Both over and under inflated conditions in pneumatic
`tires are a cause for excessive tire‘ wear resulting in
`premature tire failure. Moreover, such under and over
`in?ated tire conditions can have an adverse affect on the
`ef?ciency of operations of the vehicle as to both perfor
`mance or handling as well as vehicle fuel mileage. Since
`such conditions and results have been well known for
`- quite some time, there have been many attempts to
`develop and provide means for automatically detecting
`and reporting them. Recently, development efforts for a
`practical and inexpensive device have become more
`concentrated due to the rise in fuel and tire costs as well
`as vehicle operation costs in general. Safety continues
`also to be an important consideration.
`While there have been quite a number of prior de
`vices developed and utilized for detecting tire inflation
`conditions, these prior devices have had structural or
`operational shortcomings rendering them undesirable
`or impractical for widespread use. While the speci?c
`prior devices may have been many and varied, many
`have required special wiring and the like extending
`from the wheel assemblies to the vehicle chassis and
`then through the vehicle body to the instrument panel.
`Such wiring adds undesired cost to the system and
`moreover, is extremely difficult and time consuming to
`install. Such installation time is particularly important
`when considered on the basis of installing the devices
`during original vehicle assembly for making them a part
`of the original vehicle equipment. Further, the neces
`sary special wiring and associated equipment extending
`between the wheels and chassis are such that they are
`susceptible to damage or breakage from road materials,
`weathering, and the like encountered during normal
`vehicle use.
`There have also been some prior art attempts at de
`veloping a detector apparatus self-contained in the ‘
`wheel assembly to eliminate the necessity for wiring
`45
`and the like such as the piezoelectric reed transducer
`power supply system as disclosed, for example, in U.S.
`Pat. Nos. 4,384,482 and 4,510,484. These devices, asso
`ciated with a radio transmitter in the wheel assembly
`and a radio receiver for supplying information to the
`driver have proven to be effective, but still exhibit char
`acteristics inherent to the piezoelectric reed generators
`such as slow energy start-up activation, relatively large
`unit size requirements, expensive costs, and potential
`variations between individual units. Each of these char
`aeteristics can lead to certain operational problems and
`provide for added costs for the overall system.
`Still other systems have attempted to use a battery
`mounted in-wheel for supplying power to the transmit
`ter. These systems, however, have suffered problems
`including the size of the battery and the associated oper
`ational'life of the battery. A battery that could supply
`the needed energy was impractical due to its size and
`weight, and a battery with practical physical specifica
`tions lacked the energy storage capacity required to
`provide an adequate continuous service duration and
`other features often demanded of such a system. With
`the system being mounted in-tire, frequent battery re
`
`30
`
`35
`
`40
`
`55
`
`60
`
`65
`
`BRIEF SUMMARY OF THE INVENTION
`In accordance with the present invention, there is
`provided a self-contained device for sensing a condition
`of a pneumatic tire preferably of the type used on motor
`vehicles wherein the tires are mounted on tire rims. The
`device is provided with: a housing; a means for mount
`ing the housing to a rim and within a tire; sensing means
`associated with the housing for monitoring a condition
`within the tire; circuit means associated with the hous
`ing including a microcontroller and a radio transmitter
`circuit operatively connected to the sensing means for
`generating radio signals indicative of a tire condition;
`power supply means associated with the housing, oper
`atively connected to the circuit means, to power the
`circuit means, said power supply means including a
`battery and a centrifugal switch means adapted to ener
`gize the circuit means in a ?rst tire rotation mode and
`de-energize the circuit means in a second tire rotation
`mode; and, means for receiving said radio signals.
`In accordance with another aspect of the present
`invention, there is provided an in-tire self-contained
`device for sensing an abnormal condition of a pneu
`matic tire as set forth above wherein the microcon
`troller enters a “sleep” mode in which the microcon
`troller requires low battery power in operation.
`In accordance with yet another aspect of the present
`invention, there is provided an in-tire self-contained
`device for sensing an abnormal condition of a pneu
`matic tire as set forth above further including a switch
`ing circuit operatively connected to the sensing means
`for bypassing the centrifugal switch means upon the
`indication of an abnormal tire condition.
`In accordance with still another aspect of the present
`invention, there is provided an in-tire self-contained
`device for sensing an abnormal condition in a pneumatic
`tire as set forth above further including self-checking
`means to verify device operation.
`One bene?t obtained by an embodiment of the pres
`ent invention is a self-contained abnormal tire condition
`sensing device located within the tire which is compact,
`reliable, and nearly maintenance-free.
`Another bene?t obtained by an embodiment of the
`present invention is an abnormal tire condition sensing
`device which has a self-checking feature to ensure the
`device is operational.
`Still another bene?t obtained by an embodiment of
`the present invention is an abnormal tire condition sens
`ing device which provides immediate information on
`the condition of a tire upon ignition start-up and prior to
`the vehicle being put into motion.
`Other benefits and advantages of the various embodi
`ments of the present invention will become apparent to
`those skilled in the art upon reading and understanding
`of the speci?cation below.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The invention may take physical form in certain parts
`and arrangements of parts, the preferred embodiments
`of which will be described in detail in this specification
`and illustrated in the accompanying drawings which for
`a part hereof and wherein:
`FIG. 1 is a side elevational view in partial cross-sec
`tion of a vehicle wheel assembly having the radio trans
`
`SCHRADER
`EXH. 1005
`Page 1005-6
`
`

`

`5,285,
`189
`3
`mitter device of the present invention installed thereon
`and operatively connected to a radio receiver;
`FIG. 2 is an enlarged cross-sectional view of the
`device shown in FIG. 1;
`FIG. 3 is an electronic schematic diagram of the 5
`device shown in FIG. 1;
`FIG. 4 is an alternate electronic schematic diagram of
`the device shown in FIG. 1; and,
`FIG. 5 is another alternate electronic schematic dia
`gram of the device shown in FIG. 1.
`
`20
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`Referring now to the drawings which are for the
`purposes of illustrating the preferred embodiments of 15
`the invention only and not for the purpose of limiting
`the same, the FIGURES show a radio transmitter de
`vice A adapted for mounting on a pneumatic vehicle
`tire B. The device A includes a radio circuit 10 a control
`circuit means 11, and a battery power supply means 12
`for providing electrical energy to the circuit.
`More speci?cally and with reference to FIGS. 1 and
`2, transmitter package A includes radio transmitter 10
`for use in an abnormal condition tire warning system. A 25
`tire condition sensor 20 senses when the tire is in an
`abnormal condition and, in association with control 7
`means 11 and radio circuit 10 powered by battery means
`12, initiates an identifying signal to an associated re
`ceiver 13 in the form of an identi?cation code, as dia
`grammatically shown in FIG. 1. The radio circuit 10,
`control means 11, sensor 20, and battery means 12 are
`contained in a housing 16 typically of plastic or the like,
`including a base wall 18 which is configured for close
`reception against the wheel rim 22 in the tire wheel
`cavity. Typically, the housing 16 is attached by means
`of a band 24 and adjustable tightening means 26, as are
`known in the art.
`With reference to FIG. 3, power supply means 12 has
`a battery pair zs with a centrifugal switch 30 and associ
`ated circuitry 31. Centrifugal switch 30 is series-con
`nected with the batteries so that the current path is open
`between the battery pair 28 and the radio circuit 10
`whenever the car is stationary or moving at a rate of
`speed below some predetermined level, such as ?ve
`45
`miles per hour. That is, the centrifugal switch is ori
`ented such that its contacts remain open until the cen
`. trifugal force generated on housing 16 by a rotating
`wheel exceeds a predetermined threshold level, at
`which point the contacts close to complete the circuit
`50
`allowing energizing of circuit 10 through control means
`11. By using the centrifugal switch 30 in this manner,
`the load is electrically removed from across the batter
`ies when the wheel is stationary or operated below a
`predetermined speed. The centrifugal switch arrange
`ment also provides a means to automatically disable the
`control circuit and radio transmitter whenever the unit
`is not in its normal pressurized environment, such as in
`shipping or upon discarding, thus conserving battery
`energy and eliminating a potential source of radio inter
`ference. A battery that has proven useful in this applica
`tion is a Lithium-Carbon Mono?uoride battery -
`LIFEX FB FB2325 H2, made by Rayovac Corpora
`tion, which has a small size and exhibits a low self-dis
`charge rate with an extended operational temperature
`from below minus forty degrees Celsius (-40‘ C.) to
`over eighty-?ve degrees Celsius (85° C.) necessary for
`in-tire use.
`
`60
`
`4
`Upon closure of the centrifugal switch, the batteries
`28 power control means 11, including a microcontroller
`32 which controls the pulse duration of the radio signal,
`repetition rate, and code patterns, for encoding the tire
`pressure and sensor identification information. In accor
`dance with this invention, the microcontroller is of the
`type that has a low power consuming “sleep mode”
`within which only an internal timer remains active. This
`mode requires very little battery power. Microcom
`troller 32 is operationally connected to sensor 20, which
`typically is a pneumatic pressure switch selected to
`close at pressures above 25 psi. The microcontroller 32
`is also connected to a radio frequency circuit 10 with
`antenna 34.
`In operation, when continuously energized, the mi
`crocontroller periodically “wakes up" and executes
`resident ?rmware to check the state of its inputs, such as
`tire pressure and sensor identi?cation. The microcon
`troller 32 then in turn outputs coded information to a
`radio frequency circuit 10 for transmission to radio
`receiver 13. The microcontroller runs for a short dura
`_ tion (less than 150 milliseconds) then goes into a multi
`ple-second sleep mode which uses little energy. Typi
`cally, the duration of the sleep mode is twelve seconds
`and the energy usage in the sleep mode is less than 0.2
`milliwatts. This sleep mode feature also spaces the indi
`vidual transmissions about twelve seconds apart, which
`meets requirements set by the Federal Communications
`Commissions, and also minimizes spurious transmissions
`caused by momentary centrifugal switch closures. A
`microcontroller that has proven useful in the present
`application is an EPROM-based 8-BIT CMOS unit -
`PIC ® l6C5X, made by Microchip Technologies Inc.
`This microcontroller includes the low current sleep
`mode feature.
`In accordance with the present invention, a battery
`having a size for appropriate accommodation within a
`vehicle tire is provided with a centrifugal switch and
`microcontroller with low power sleep mode. By utiliz
`ing the low power consuming sleep mode of the mi
`crocontroller and the centrifugal switch shut-off func
`tion, suf?cient battery energy capacity is available to
`allow the system to signal periodically regardless of
`pressure, thus providing a “self-checking” feature for
`the system. That is, the system not only discriminates
`tire pressure data when “awake”, but also transmitter
`and sensor identi?cation codes on a vehicle, thereby
`providing the self-checking feature which alerts a
`driver of general system problems such as a low battery,
`or transmitter/sensor malfunction. This is accomplished
`by providing the receiver 13 with a free-running
`“watchdog” counter wherein successive transmissions
`of sensor identi?cation codes serve to reset the counter
`preventing an alarm condition. If at any time the
`"watchdog” counter reaches its limit without a reset
`ting transmission of sensor identi?cation codes originat
`ing from any of the multiple sensors on the vehicle, an
`alarm is generated by the receiver 13 identifying a fault
`condition and its source. In short, a reliable abnormal
`tire condition sensing system is provided with a contin
`uous self-checking system. The system has a long
`maintenance-free life, typically in excess of eight years
`of normal vehicle operation.
`In one operating embodiment, the following exem
`plary components and circuit values were employed in
`the radio transmitter device of FIG. 3. These compo
`nents and values are in no way to be deemed as the
`overall inventive concepts involved.
`
`40
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`55
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`65
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`SCHRADER
`EXH. 1005
`Page 1005-7
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`

`

`5
`
`Description
`100K OHM
`3(DK OHM
`1K OHM
`1 uF
`100 pF
`47 pF
`10 pF
`NPN RF Transistor
`1 MHZ Resonator
`6 Volt Battery
`
`Component
`R1, R2,
`R3
`R4
`Cl
`C2, C3
`C4
`C5
`Q1
`CR1
`BA'ITl
`
`characters.
`
`_
`
`,
`
`FIG. 4 shows an alternate embodiment of the radio
`transmitter device of the present invention which is
`similar in operation and design to the device of FIG. 3,
`but includes additional instant abnormal tire indication.
`For ease of illustration, and discussion, like elements
`will be referred to by like characters with a primed (')
`suffix, and new elements will be referred to by new
`20
`
`15
`
`5,285,189
`6
`rotation frequency exceeds a predetermined level clos
`ing the centrifugal switch 30", or (2) abnormal tire
`pressure, opening the contacts of sensor pressure switch
`20". This embodiment provides for the transmission of
`actual tire pressure measurement data (or temperature
`data) even when the vehicle is not in motion where the
`tire is in an abnormal in?ation condition. The tire pres
`sure measurement data is provided to the vehicle opera
`tor instantly upon ignition start-up when an abnormal
`tire condition exists, so long as the receiver module is
`energized. A temperature transducer and necessary
`support circuit may be added along with the pressure
`transducer 21 to enable the microcontroller 32" to de
`liver both actual temperature and actual pressure infor
`mation by multiplexing the two separate transducers.
`This invention has been described with reference to
`certain preferred embodiments. Obviously modi?ca
`tions and alterations will occur to others upon reading
`and understanding of the speci?cation. It is our inten
`tion to include all such modi?cations and alterations
`insofar as they come within the scope of the appended
`claims or the equivalents thereof.
`What is claimed is:
`1. A device for sensing a condition of a pneumatic tire
`comprising:
`‘
`-
`
`In this embodiment, the sensor-pressure switch 20' is
`placed across batteries 28’ to shunt the centrifugal
`switch 30' when pressure switch 20’ indicates an abnor
`mal tire condition. This provides for a signal even when
`the vehicle is not in motion. With this embodiment, the
`transmission of an abnormal tire condition such as pres
`sure or temperature is provided to the driver instantly
`upon ignition start-up so long as the receiver module 13’
`(not shown) has power applied to it.
`In this second operating embodiment of FIG. 4, the
`following exemplary components and circuit values
`were employed in the radio transmitter device. These
`components and values are in no way to be deemed the
`overall inventive concepts involved.
`
`30
`
`35
`
`Component
`R1’
`R2’
`R3’
`R4’
`Cl
`C2’, C3’
`C4’
`C5’
`D1
`Ql'
`Q2
`Q3
`CR1‘
`BATTl'
`
`Description
`10M OHM
`100K OHM
`300K OHM
`1K OHM
`1 uF
`100 pF
`47 pF
`10 pF
`diode
`PNP Switching Transistor
`NPN Switching Transistor
`NPN RF Transistor
`1 MHZ Resonator
`6 Volt Battery
`
`50
`FIG. 5 shows yet another alternative embodiment of
`the present invention which is similar in operation and
`design to the device of FIG. 4, but includes means for
`actual tire pressure measurement indication. Such
`means could also provide for temperature measurement
`indication. For ease of illustration and discussion, like
`elements (FIGS. ‘3 and 4) will be referred to by like
`characters with a double primed suffix ("), and new
`elements will be referred to by new characters.
`In this embodiment, a pressure transducer/condition~
`ing circuit 21 as is known in the art is connected to the
`microcontroller 32" to provide for the ability to encode
`and deliver a direct pressure measurement to read out to
`the vehicle operator (i.e., 20 psi, 21 psi, etc.). The circuit
`21 is connected to microcontroller 3 " so that it is peri
`odically energized upon command by the microcon
`troller when the microcontroller is activated by either
`one or both of the following conditions: (I) the tire
`
`55
`
`60
`
`65
`
`a housing;
`means for mounting said housing within said tire;
`sensing means associated with said housing for moni
`toring a condition within the tire;
`circuit means associated with said housing including:
`a radio transmitter circuit operatively connected to
`said sensing means for controlling and generat
`ing radio signals indicative of said tire condition;
`and,
`a microcontroller having a low power mode dur
`ing operation of the device, means for monitor
`ing device parameters and means for periodically
`generating said radio signals in an absence of an
`abnormal tire condition, thereby providing for
`self-checking of the device in operation;
`power supply means associated with said housing
`operatively connected to said circuit means to
`power the circuit means and to enable the genera
`tion of the radio signals, said power supply means
`including a battery adapted to be contained within
`said tire and a centrifugal switch means adapted
`with said battery to render the circuit means de
`energized in a ?rst stationary and low tire rotation
`mode and energized in a second high tire rotation
`mode; and,
`means for receiving said radio signals.
`2. The device of claim 1 wherein said microcontroller
`comprises means for. selectively operating in said low
`power mode for nearly all the time it is energized in said
`second high tire rotation mode, said low power mode
`operating means having an internal timer which causes
`said microcontroller to wake up from said low power
`mode.
`3. A device for sensing a condition of a pneumatic tire
`mounted on a tire rim comprising:
`a housing;
`a means for mounting said housing within said tire;
`sensing means associated with said housing for moni
`toring said condition within the tire;
`circuit means associated with said housing including:
`a radio transmitter circuit operatively connected to
`said sensing means for controlling and generat
`
`SCHRADER
`EXH. 1005
`Page 1005-8
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`

`

`10
`
`20
`
`35
`
`40
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`5,285,189
`7
`8
`ing radio signals indicative of said tire condition;
`mode thereby with said microcontroller greatly
`and,
`limiting power required from the battery and in
`creasing battery life; and
`a microcontroller having a low power mode dur
`ing operation of the device, means for monitor
`means for receiving said radio signals.
`ing device parameters and means for periodically
`7. A method of monitoring a pneumatic tire condition
`generating said radio signals in an absence of an
`for use with an apparatus having a transmitter device
`abnormal tire condition, thereby providing for
`including a power supply including a battery adapted
`self-checking of the device in operation;
`for mounting in said tire, a centrifugal switch, a condi
`power supply means associated with said housing,
`tion sensor, microcontroller with an extended low
`opweratively connected to said circuit means to
`power consumption mode when energized during oper
`power the circuit means and to enable the genera
`ation of the device, and a radio signal generating circuit,
`tion of the radio signals, said power supply means
`and a receiver device for receiving radio signals, the
`including a battery adapted to be contained within
`method comprising the steps of:
`said tire and a centrifugal switch means adapted to
`disposing the transmitter device within the pneumatic
`render the circuit means de-energized in a ?rst 15
`tire;
`stationary and low tire rotation mode and ener
`sensing a rotational frequency of the pneumatic tire
`gized in a second high tire rotation mode;
`with the centrifugal switch above a predetermined
`switching circuit means operatively connected to said
`threshold rotational frequency;
`sensing means for bypassing the centrifugal switch
`enabling the microcontroller by connection to the
`means upon an indiction of an abnormal tire condi
`power supply through the centrifugal switch when
`tion; and
`the sensed rotational frequency exceeds the prede
`means for receiving said radio signals.
`termined threshold frequency;
`4. The device of claim 3 wherein said microcontroller
`using the microcontroller to monitor apparatus pa
`comprises means for selectively operating in said low
`rameters; controlling the radio signal generating
`power mode for nearly all the time it is energized in said
`25
`circuit to generate a ?rst radio signal indicative of
`second high tire rotation mode, said low power operat
`an abnormal tire condition;
`.
`ing means having an internal timer which causes said
`sensing said pneumatic tire condition with the condi
`microcontroller to wake up from said low power mode.
`tion sensor;
`5. The device of claim 3 further including a pressure
`controlling the radio signal generating circuit with
`transducer means associated with said housing opera
`the enabled microcontroller to periodically gener
`tively connected to said microcontroller for providing
`ate a second radio signal representative of the
`' tire pressure measurement data to said microcontroller
`sensed pneumatic tire condition at a predetermined
`upon command from said microcontroller.
`rate in an absence of an abnormal tire condition to
`6. A device for sensing an abnormal condition of a
`provide a self-checking of the transmitter device;
`pneumatic tire preferably of the type used on a motor
`and
`vehicle wherein the tire is mounted on a tire rim com
`prising:
`receiving the generated periodic radio signal with the
`a housing;
`receiver device.
`'
`8. The method of monitoring a pneumatic tire condi
`a means for mounting said housing within said tire;
`tion according to claim 7, further comprising enabling
`sensing means associated with said housing for moni
`the microcontroller by connection to the power supply
`toring the abnormal condition within the tire;
`using the condition sensor when the sensed pneumatic
`circuit means associated with said housing including a
`tire condition is within a predetermined range.
`microcontroller and oscillator circuit and a radio
`9. The method of monitoring a pneumatic tire condi
`transmitter circuit operatively connected to said
`tion according to claim 7, further comprising:
`sensing means for controlling and generating radio
`sensing pressure within the pneumatic tire;
`signals indicative of said abnormal tire condition,
`encoding the generated second radio signal with tire
`said microcontroller having a low power consump
`tion mode, means for selectively operating in said
`pressure information and transmitter device identi
`?cation information; and,
`low power consumption mode for nearly all the
`receiving the encoded radio signal and decoding the
`time energized, means for monitoring device pa
`rameters and means for periodically generating
`tire pressure information and the transmitter device
`said radio signals in an absence of said abnormal
`identi?cation information with the receiver device.
`tire condition, thereby providing for self-checking
`10. The method of monitoring a pneumatic tire condi
`of the device in operation;
`tion according to claim 9, further comprising:
`power supply means associated with said housing
`controlling the radio signal generating circuit with
`the microcontroller to periodically generate the
`operatively connected to said circuit means to
`power the circuit means and enable the generation
`encoded radio signal at a ?rst frequency; '
`of the radio signals, said power supply means in
`receiving the periodic encoded radio signal with the
`cluding a battery adapted to be contained within
`receiver device; and,
`said tire and a centrifugal switch, the centrifugal
`generating an alarm with the receiver device when
`switch adapted to render the circuit means de-ener
`the first frequency is less than said predetermined
`gized in a ?rst stationary and low tire rotation
`rate.
`mode and energized in a second high tire rotation
`
`a a c a a
`
`50
`
`55
`
`65
`
`SCHRADER
`EXH. 1005
`Page 1005-9
`
`