Abstract: The invention relates to a method for detecting a drop in pressure of a motor vehicle tire by evaluating wheel speeds determined by sensors. The method for detecting the drop in pressure is based on the detection of a large drop in pressure or a complete drop in pressure using a reduction of the angular velocity or an increase (8) in the dynamic read radius rd of one or more wheels. The invention also relates to a device for controlling the braking power and/or driving dynamics and for measuring the pressure of vehicle tires wherein a microcomputer, which is connected to wheel rotational speed sensors and optionally to driving dynamic sensors, is used to perform the aforementioned method and a known method for regulating the braking power and/or driving dynamics.

Abstract: The present invention describes a method for detecting a tyre pressure drop in motor vehicles including the following steps:

Abstract: A method for detecting decrease in tire air-pressure for detecting decrease in internal pressure of a tire on the basis of rotational information obtained from tires attached to a vehicle. A threshold for judging decrease in air-pressure of following wheels is different from a threshold for judging decrease in air-pressure of driving wheels. Threshold for judging abnormalities in air-pressure are varied for judging abnormalities of tire air-pressures of following wheels and for judging abnormalities of tire air-pressure of driving wheels so that appropriate judgment of abnormalities in air-pressure can be performed.

Abstract: A self training tire pressure monitoring system for a vehicle includes at least two pressure sensors, at least two wheel sensors and a control. The pressure sensors are positioned at respective tires and are operable to provide a measured pressure output indicative of the pressure of the respective tires. The wheel sensors are positioned at respective wheels of the vehicle and are operable to provide a characteristic output indicative of rotation of the wheels over a period of time. The control receives the characteristic outputs and the measured pressure outputs and is operable to integrate the outputs to determine the particular wheels at which the pressure sensors and associated tires are positioned. The measured pressure and location of the tires may be displayed at a display of the vehicle. Preferably, the control deduces a deduced rolling radius of the tires in response to the characteristic output of the wheel sensors.

Abstract: An apparatus for alarming decrease in tire air-pressure which detects the decrease in internal pressure of the tire based on wheel speed information obtained from wheels of a vehicle and accordingly alarms a driver. The apparatus comprises: a wheel speed information detecting means, a memory means for storing the wheel speed information of the respective tires, a calculating means for calculating a judged value based on a vehicle velocity and wheel speed information, and a judging means for determining a decrease in tire air-pressure based on correlation of the vehicle velocity and an outer diameter of the tire at the time of performing high-speed running. It is possible to determine a decompression of a tire based on the correlation also in case the judged value will not become large owing to increased influence of centrifugal force during high-speed running even though a tire is in a decompressed condition.

Abstract: A transmitter, which is operated by a battery, wirelessly transmits data including data that represents the temperature T in a tire and data that represents the voltage V of the battery. A receiver judges whether or not the life of the battery is ending depending on the battery voltage V read from the received data. More specifically, the receiver performs the judgment regarding the life of the battery based on a comparison between the battery voltage V and a variable voltage reference value V0, which is selected in accordance with the temperature T in the tire. The judgment regarding the life of the battery is thus accurately performed.

Abstract: The present invention, in certain embodiments, is an apparatus to indicate the presence of an under-pressurized pneumatic tire for a vehicle, including, trailers, tractors, trucks or passenger vehicles. The apparatus comprises a housing, a cap, a shaft, a probe element, a bracket, an electrical switching element an electrically powered alarm. The housing is mounted next to the axle for the wheel of the vehicle. The cap is attached to the housing and has an aperture to receive the shaft. The shaft extends through the cap, and at one end, receives the probe element, and at the other end, holds the bracket upon which the electrical switching element is attached. When a tire loses air pressure, the height of the tire, as well as the vertical distance from the axle to the travelling surface, decreases; as the vertical distance decreases, the probe element contacts the travelling surface and rotates the shaft, bracket and electrical switch.

Abstract: The present invention, in certain embodiments, is an apparatus to indicate the presence of an under-pressurized pneumatic tire for a vehicle, including, trailers, tractors, trucks or passenger vehicles. The apparatus comprises a housing, a cap, a shaft, a probe element, a bracket, an electrical switching element an electrically powered alarm. The housing is mounted next to the axle for the wheel of the vehicle. The cap is attached to the housing and has an aperture to receive the shaft. The shaft extends through the cap, and at one end, receives the probe element, and at the other end, holds the bracket upon which the electrical switching element is attached. When a tire loses air pressure, the height of the tire, as well as the vertical distance from the axle to the travelling surface, decreases; as the vertical distance decreases, the probe element contacts the travelling surface and rotates the shaft, bracket and electrical switch.

Abstract: A system for detecting a deflated tire on a vehicle. The system includes an evaluating process that determines when a tire is likely to be deflated and issues a warning when the evaluating process determines a tire is likely to be deflated. The system further includes a feedback component that provides feedback to the evaluating process indicating whether the issued warning was erroneous. In one aspect of the invention, the feedback component makes corrections to the evaluating process. In another aspect of the invention, the feedback component is a direct feedback component. In yet another aspect of the invention, the feedback component is an inferred feedback component.

Abstract: The present invention is a novel technique and system that allows the pressure of a tire to be remotely monitored by sensing a tire parameter indicative of the tire's pressure without mounting any device on the tire itself, while the tire is or is not rotating. In the illustrative embodiment, a tire parameter indicative of the pressure inside the tire, such as the temperature, acoustical signature, or shape of the tire, is measured remotely with a remotely mounted sensor. The measured parameter is compared to a range of known acceptable limits for that particular parameter, and a warning signal is generated if the measured parameter is not within that range of acceptable limits.

Abstract: A low-pressure testing device for an automobile tire has a base, a warning device, two parallel separated resilient tubes The base is firmly placed on the ground. The warning device is mounted on one end of the base and has a first switch, a second switch and a warning circuit. Each of the parallel separated resilient tubes has a first closed end and a second end connected to the first switch or the second switch, as appropriate. When the two tubes are pressed simultaneously, the first and second switches close the warning circuit to sound an alarm.

Abstract: An apparatus for alarming decrease in tire air-pressure based on rotational information obtained from tires, comprising a rotational information detecting means for detecting rotational information of each tire, a steering angle detecting means, a memory means for storing the rotational information of each tire and the steering angle, a turning radius calculating and processing means, a judged value calculating and processing means, and a correction means for correcting the turning radius. It is possible to obtain an accurate turning radius also in case any tire of the following wheels is decompressed by correcting the turning radius obtained on the basis of rotational information by using the steering angle information, thereby the DEL value might be obtained in a more accurate manner than compared to conventional arrangements.

Abstract: A vehicle-mountable, suspension monitoring system produces suspension-analysis information which can be used to determine adjustments to a vehicle suspension. Sensor structure located adjacent the vehicle suspension is connected to a control/processing/display (CPD) unit located adjacent the vehicle operator. The sensor structure senses suspension related information and communicates the suspension related information to the CPD unit. The CPD unit receives the suspension related information and converts it to suspension-analysis information. The CPD unit stores the suspension-analysis information and displays it to the vehicle operator. Alternatively, the suspension-analysis information is downloaded from the CPD unit to a digital computer for display as waveform data.

Abstract: A system has been invented for monitoring at least one tire of a towed vehicle, the system in one aspect using mechanical indicators in conjunction with appropriate electrical wiring circuits and lights or other warning apparatus at a driver's position in a towing vehicle to signal the lowering of a tire due to loss of air pressure in the tire. Certain embodiments of such a system do not require the use of a monitoring camera and related video apparatus. In other systems according to the present invention, one or more cameras are used to provide a real-time view of either the tire(s) of a towing vehicle, tire pressure indicator(s), or both.

Abstract: A method and apparatus for connecting an electronic monitoring device to a pneumatic tire includes mounting the monitoring package of the monitoring device within the body of the tire or the body of a patch and subsequently connecting the power source to the monitoring package through electrical coupling. The method allows the monitoring package to be cured within the tire or the patch at relatively high temperatures while protecting the sensitive power source from the high temperatures. The use of electrical coupling to achieve the power transfer prevents the material surrounding the monitoring package from being pierced by an element that would form the direct electrical connection. The method allows the monitoring package and its antenna to be positioned in a variety of positions on or within the pneumatic tire.

Abstract: A tire inflation gas telemetry system (30) is installed inside a tire (174) mounted to a wheel (170) and is placed within a protective housing (100) having pneumatic cylinders (116, 126) with piston rods (128, 130) that are extended or retracted by tire inflation gas pressure changes. The housing is suspended by a cable (156) slung around the wheel. The cable is slack or taut depending on motion of a first piston rod, and the telemetry system is pivoted into alternate protected and operational orientations by motion of a second piston rod. When the tire is uninflated, the cable is slack, and the telemetry system is pivoted into the protected orientation. As the tire is inflated, the cable becomes taut causing the housing to be drawn tightly against the wheel, and the telemetry system is pivoted into the operational orientation.

Abstract: A system has been invented for monitoring at least one tire of a towed vehicle, the system in one aspect using mechanical indicators in conjunction with appropriate electrical wiring circuits and lights or other warning apparatus at a driver's position in a towing vehicle to signal the lowering of a tire due to loss of air pressure in the tire. Certain embodiments of such a system do not require the use of a monitoring camera and related video apparatus. In other systems according to the present invention, one or more cameras are used to provide a real-time view of either the tire(s) of a towing vehicle, tire pressure indicator(s), or both.

Abstract: A system (10) for monitoring a condition of a tire (12) of a vehicle (14) includes a tire-based unit (20) and a vehicle-based unit (40). The tire-based unit monitors a condition of the tire (12), assembles data indicative of the monitored condition, and transmits at least one radio frequency signal (32) including a signal indicative of the data. The vehicle-based unit (40) receives the radio frequency signal (32) and determines an actual reception success rate of the radio frequency signal. The vehicle-based unit (40) compares the actual reception success rate of each radio frequency signal (32) to known reception success rates corresponding to known tire positions on the vehicle (14) and identifies one of the known reception success rates that is closest to equal the actual reception success rate. The vehicle-based unit (40) associates the radio frequency signal (32) with the known tire position corresponding to the one of the known reception success rates.

Abstract: A warning system to alert the driver of a vehicle that a tire or wheel on the vehicle has become loose or a tire tread is separating from a tire core is disclosed. The warning system comprises a first metallic member mounted to the vehicle, a second metallic member mounted adjacent the surface of the tire being monitored and in a spaced-apart relationship with respect to the first member and an insulating member interposed between the first and second members forming a normally open electrical contact between the first and second members. When a tire or wheel becomes loose on the vehicle or a tire tread starts separating from its tire core, the surface of the tire contacts the second member causing it to move laterally and contact the first member resulting in the closing of the normally open electrical contact between the first and second members causing an audible and visual alarm to be actuated alerting the driver of the vehicle of a dangerous condition.

Abstract: An apparatus for alarming decrease in tire air-pressure which alarms decrease of internal pressure of a tire on the basis of a rotational information obtained by tires attached to a four-wheeled vehicle. The apparatus comprises rotational information detecting means; memory means for storing the rotational information; calculation processing means for calculating a reciprocal number of a turning radius and calculating a judged value; first judging means for comparing the judged value with a reference value at every regions of the turning radius; and second judging means for canceling a judgement of decrease of internal pressure when a difference between the judged values in the right and left turning regions is different from a difference between reference judged values in the right and left turning regions which are obtained at a time of initializing run.

Abstract: An arrangement for provision of vehicle tire sensory information while a tire (12) is mounted on a wheel rim (10) of a vehicle. A sensor unit (16) includes a tire condition sensor (e.g., electronics 38), a signal transmitter (36), and a housing (20) that contains the sensor and the transmitter. The housing (20) has a mounting hole. A stud (18) is welded to the rim (10) and extends into the space bounded between the tire (12) and the rim (10). The stud extends through the mounting hole of the sensor housing (20). A retainer (e.g., 26) extends between the sensor housing (20) and the stud (18) such that the sensor housing is held fixed relative to the stud.

Abstract: A vehicular tire inflation monitoring system is provided for a vehicle that includes at least one tire inflation indicator assembly, visible exterior of the vehicle, positioned at an exterior vehicle portion, such as at an exterior rearview mirror assembly. The at least one tire inflation indicator assembly provides an indication of the inflation condition of at least one of the vehicle tires. The tire inflation monitoring system includes a control receiving at least one input from at least one tire pressure sensor sensing pressure of at least one vehicle tire. The control produces an output to illuminate the at least one tire inflation indicator assembly.

Abstract: The present invention is a novel technique and system that allows the pressure of a tire to be remotely monitored by sensing a tire parameter indicative of the tire's pressure without mounting any device on the tire itself, while the tire is or is not rotating. In the illustrative embodiment, a tire parameter indicative of the pressure inside the tire, such as the temperature, acoustical signature, or shape of the tire, is measured remotely with a remotely mounted sensor. The measured parameter is compared to a range of known acceptable limits for that particular parameter, and a warning signal is generated if the measured parameter is not within that range of acceptable limits.

Abstract: The vehicle surroundings monitor detects the sizes and positions of obstacles, ditches and humans as well as the depths of the ditches to provide the driver with sufficient information to secure safety during driving. The pattern light projector receives an incoming laser beam and projects a light spot matrix in the form of a regular grating onto the monitored area. The camera photographs the light spot pattern on the monitored area and sends image signals to the data processor which processes the image signals to detect the presence of any obstacle, ditch or human. Based on the steering angle detected by the steering angle sensor, the path the car will take is predicted and a possible contact or collision of the car with the obstacle is detected beforehand. The buzzer, voice synthesizer and display device are used to alert the driver and indicate the presence of the obstacles, the possible contact with them and the location where the possible contact will occur.

Abstract: A vehicle wheel information supply device for supplying wheel information relating to a state of a wheel of a vehicle, including a wheel state detector for detecting the state of the wheel, a wheel information generator for generating the wheel information relating to the state of the wheel, on the basis of an output of the wheel state detector, a transmitter for transmitting the wheel information, and a receiver which receives the wheel information transmitted by the transmitter, the wheel state detector, the wheel information generator and the transmitter being disposed on the wheel while the receiver being disposed on a body of said vehicle, wherein the wheel information generator is capable of selectively generating different kinds of wheel information having respective different volumes, and at least one of the wheel information generator and the transmitter operates in a manner depending upon at least one parameter indicative of the state of the wheel, which at least one parameter is detected by the whe

Abstract: A tire pressure-monitoring system for use with a trailer. The monitoring system includes an inductive proximity sensor mounted adjacent each wheel. To activate the sensors, a target is mounted on each brake drum. Rotational speed data for each wheel is relayed from each sensor to a programmable logic controller which compares the rotational speed of a wheel with another wheel. Sensitivity parameters written into the program contained in the programmable logic controller compares the input data and, if the data falls outside the safe parameters, alerts the driver by activating and audio or visual alarm mounted within the tow vehicle. The sensitivity of the programmed logic may be optimized to differentiate changes in a tire diameter due to turning versus an actual loss in tire pressure.

Abstract: A system has been invented for monitoring at least one tire of a towed vehicle, the system in one aspect using mechanical indicators in conjunction with appropriate electrical wiring circuits and lights or other warning apparatus at a driver's position in a towing vehicle to signal the lowering of a tire due to loss of air pressure in the tire. Certain embodiments of such a system do not require the use of a monitoring camera and related video apparatus. In other systems according to the present invention, one or more cameras are used to provide a real-time view of either the tire(s) of a towing vehicle, tire pressure indicator(s), or both.

Abstract: Wheel speed values for each of four wheels are collected and statistically analyzed axle by axle for a difference which could indicate low tire pressure. Prior to analysis, and following reset of the system, calibration factors are determined for each axle to compensate for rolling radius variation, and are subsequently used to correct the percentage difference values for the two wheels on any one axle. When a sufficient number of values have been collected, a t0 value is calculated for each axle according the paired t-test statistical method or a slight variation thereof The t0 value for each axle is then compared to a respective empirical value based on a predetermined pressure loss. This comparison can provide the basis for a driver warning. Various types of filters can be used prior to calculating the t0 values to eliminate data that may lead to improper deflation detection.

Abstract: A time-independent, event-based system for receiving and discriminating unique codes from multiple transmitters has an event-based detection cycle instead of a time-based detection cycle. The system detects received ID codes from multiple transmitters and compares the received ID codes with registers for ID codes in an array in memory. Counters corresponding to the stored ID codes increment each time there is a match between the received ID code and the stored ID code. After a predetermined total number of increments, the system evaluates the received signals to discriminate between ID codes received from desired transmitters and those from undesired transmitters before resetting the counter. Because the system is event based and not a function of time, it will operate over a wide range of time cycles.

Abstract: In a vehicle having wheels with inflatable tires, position generators are assigned to each wheel to detect the distances between the wheel and the vehicle body. It is determined whether the time related mean wheel centers are situated approximately in a common plane. If not, a warning signal is generated, indicating defective tire air pressure.

Abstract: A tire-safety sensing device includes a supporting rod having one end connected to the body of the vehicle, located beside a tire, a fixing peg to pivotally connect the sensing device to a sensing rod to provide swinging motion, a contacting wheel with a bearing mounted onto the top end of the sensing rod, a spring (tortional spring) being mounted to the fixing peg, the two ends of the spring being mounted to a protrusion within a notch provided at the supporting rod and a protrusion of the sensing rod, the spring urges the sensing rod towards the tire such that the contacting wheel is in contact with the tire.

Abstract: A central tire inflation system for a work vehicle is presented. The central tire inflation system controls the inflation pressure in the tires of a work vehicle. The central tire inflation system may be placed in an automatic or manual mode. In the automatic mode, the system makes changes to the tire pressures according to the tire parameters, terrain conditions, and the operating loads placed on the tires.

Abstract: An apparatus for monitoring tire pressure on automobiles, having an arrangement (1), intended for installation into a wheel, made up of a pressure sensor, a transmitter, and a circuit for operating the pressure sensor and transmitter, and having a battery (2) which supplies the circuit with power via a power supply line (3), the arrangement (1) and the battery (2) being located in a sealed housing (9). Located in the power supply line (3) is an electronic switch (4) which has a control electrode (5) and is nonconductive when the control electrode (5) is connected to ground.

Abstract: A tire diagnostic system and method for detecting an inflation condition of a pneumatic tire on an automotive vehicle includes a method for estimating the inevitable pressure loss of the tire. The method creates the estimate based on a combination of a time since the tire was last set to a nominal value and an operating condition of the vehicle. For example, the estimate can be based on a combination of time and distance traveled since the tire was last set to a nominal value.

Abstract: A tire monitoring and warning assembly 10 which monitors and measures attributes or characteristics of at least one of the selectively inflatable tires 14-20 of a vehicle 12 and which compares the obtained measurements with a stored value which represents a value of the attribute or characteristic occurring or existing when the at least one tire 14-20 is desirably inflated, and which, based upon the comparison, warns the driver if the at least one of the tires 14-20 is deflated.

Abstract: A vehicle, such as a trailer, having a low tire warning and weight transfer system. The trailer has tandem wheel sets located on each side. The two tires of each tandem wheel set are each rotatably attached to a walking beam assembly which, in turn is attached to the trailer. The walking beam assembly has a horizontal walking beam that is substantially parallel to the ground when both tires of the adjacent wheel set are fully inflated. Walking beam stops are located on the trailer body adjacent each end of the walking beam. At least part of the stops intersect the vertical plane of the adjacent walking beam at a site above and/or below the beam. When one of the tires of a tandem wheel set becomes at least partially deflated, at least one end of the same side walking beam comes into contact with the adjacent stop, which prevents further movement of the walking beam assembly and shifts weight to the other, fully inflated tire.

Abstract: The system is for use in monitoring one or more vehicle tires to detect the onset of tire tread separation. Tire tread separation occurs when the surface layers of a tire are separated from the underlying body or carcass. The system of the present invention can detect the onset of this condition and warn a driver so that appropriate safety measures can be taken. In its broadest context, the detection system of the present invention includes a sensor for transmitting and receiving a beam of energy; a ranging unit for determining the distance between the sensor and the surface of the tire being monitored; a data acquisition unit for determining when a tire tread separation condition is present; and an alarm for alerting a driver of a dangerous tire tread condition. The system can be use to monitor either one tire or a pair of tires.

Abstract: A system and method that monitors four wheel sensors of an automotive vehicle to determine changes in the effective rolling radii of any wheel and a low pressure tire condition. Certain vehicle operating conditions, such as excessive or very low speeds, driven wheel torque, braking, and turns, are determined from the sensor outputs and are used to prevent erroneous detection of changes in effective rolling radius. Data from the sensors that is determined to be acceptable is accumulated over time as displacement values for each wheel. When the displacement values exceed a predetermined value, a metric function is used to compare differences detected in accumulated displacement values for the front pair of wheels and for the rear pair of wheels. If the difference between compared pairs of wheels is excessive, as compared with a predetermined baseline metric value, a low tire condition is detected.

Abstract: To accurately detect a resonance frequency of tire even in high speed range by which tire air pressure state of each wheel is known, a calculation processing unit to which detection signals of wheel speed and resonance frequencies of tire are inputted calculates a timewise change amount of a wheel speed deviation that is a difference between wheel speed ratios of front and rear wheels. Then, it makes corrections to remove the influence of timewise change amounts of resonance frequencies of front wheels from timewise change amounts of wheel speed deviations based on a relationship between the resonance frequency and the wheel speed deviation when air pressure of the tire is changed.

Abstract: A method for monitoring various engineering conditions of a pneumatic tire such a temperature, pressure, tire rotation and other operating conditions of the tire. A tire tag is mounted on the interior of the tire within the pressurizable cavity and contains the stored data and sensors for detecting certain conditions within the cavity. A separate transponding device is mounted on the tire rim. The tire tag contains a battery, an antenna and stored data pertaining to the tire. The transponding device uses electronic circuitry which collects data from the tire tag. The tire tag is actuated by transmitted radio frequency waves from the transponding device, which data is retransmitted by the transponding device to the remote location by an antenna which extends from the transponding device through the rim to a location externally of the tire.

Abstract: Device for monitoring the tires of a vehicle, comprised of a central unit d for each wheel a measurement sensor, a rotating antenna, a stationary antenna, and metallic parts of electromagnetic coupling placed in the environment of the wheel, the hub, and the spindle.

Abstract: An apparatus for detecting the drop in air pressure of any of tires mounted on a vehicle. The device finds, in finding an initial correction factor for eliminating the effect of a difference in effective rolling radius depending on an initial difference among the tires on the rotational angular velocities of the tires, the ratio of the rotational angular velocities of a predetermined pair of the tires as an initial correction factor, averaging and updating the initial correction factor for each sampling period, and taking the initial correction factor found when the number of times of the updation reaches a predetermined number of times as the final initial correction factor. When it is judged that the air pressure of any of the tires drops before the final initial correction factor is found, the calculation of the initial correction factor is stopped.

Abstract: A reduction in tire pressure in follower wheels and driven wheels is precisely determined irrespective of slipping states of the driven wheels through the use of apparatus wherein in a driven wheel slip amount calculating means M4 calculates a driven wheel slip amount KIDD as a left and right follower wheel speed difference FID and a left and right driven wheel speed difference RID; in a driven wheel torque calculating means M5, a driven wheel torque TQDW is calculated; in a driven wheel slip amount estimating means M6, a characteristic of variation in driven wheel slip amount KIDD relative to the variation in driven wheel torque TQDW is estimated using a least squares method; in a deviation calculating means M7, a deviation CKID between the follower wheel speed difference FID and the driven wheel speed difference RID in a state in which the driven wheels are not slipping, is calculated as an intercept of the driven wheel slip amount KIDD at a driven wheel torque equal to 0 (zero) in a graph of the variation

Abstract: The invention provides a method and apparatus for monitoring tires on a vehicle to detect adverse tire operating states, by continuously measuring the distance between the associated vehicle axle (or a vehicle body part rigidly connected thereto) and the road while the vehicle is in operation. From this measurement, the tire deflection is determined, which represents a comparatively exact measure of the respective tire load. When the tire deflection determined leaves a predetermined desired range, a warning signal is transmitted.

Abstract: An apparatus for alarming of tire deflation is provided in which reliability of an alarm is raised by a manner of alarming slightly when tire deflation is small and detection accuracy of a deflation detection mechanism is small, while alarming largely when tire deflation is large and deflation is detected with large accuracy. The apparatus comprises deflation detection means for detecting tire deflation; vehicle speed detection means for detecting a speed of a vehicle; and alarm means for deciding an alarm level depending on a detected tire deflation and a detected vehicle speed, and providing an alarm at the decided alarm level.

Abstract: An electronic controller applies a braking force to selected wheels when sudden tire rupture is detected. A tire rupture signal indicative of whether a tire on the vehicle has ruptured is generated. Signals corresponding to a desired trajectory of the and the actual trajectory of the vehicle are calculated. Corresponding brake actuator signals are generated and applied to appropriate brakes of the vehicle, controlling the actual trajectory of the vehicle.

Abstract: A tire deflation alarm apparatus to be provided on a vehicle with air-filled tires, comprising: a timer for measuring a period of time from when the air pressure of a tire is set to a normal value to the time when the air pressure spontaneously drops to a dangerous value, the period of time being established beforehand; an alarm portion connected to the timer and designed to give an alarm after the period of time has elapsed; and a reset switch for resetting the timer to the zero hour. The apparatus is capable of warning the tire's spontaneous air pressure drop that inevitably occurs when allowed to stand.

Abstract: A pressure sensing system is formed by a sensor mounted one to rotate with each tire and adapted to sense the pressure in the tire and generate a signal corresponding to the tire pressure, a movable contact system is moved into an operative position only when the vehicle is stopped and provides power (if required) to the sensor and contacts to deliver the electrical signals indicative of the tire air pressure to the vehicle body where it may be displayed for the operator's convenience.

Abstract: A tire pressure detector includes a casing that receives a battery unit and a signal generating unit therein and that is provided with an adaptor to engage an inflating valve of a tire. A switch unit is mounted in the adaptor for connecting electrically the battery unit and the signal generating unit, and includes a resilient disc member with a peripheral portion secured to an inner wall of the adaptor, and a central portion moving in accordance with pressure inside the tire. An annular conductive piece is disposed on an inward protrusion of the adaptor and is connected to the signal generating unit. A conductive tubular body is disposed on the central portion of the disc member and extends slidably through the inward protrusion of the adaptor. The tubular body has a peripheral flange projecting outwardly from an upper end thereof and extending above the conductive piece. A hollow conductive seat member is mounted in the adaptor above the tubular body. The seat member is connected to the battery unit.

Abstract: A tire pressure monitor apparatus comprising a vehicle body, four vehicle wheels including tires disposed at four comers of the vehicle body, four position sensors, one mounted between each wheel and the corresponding corner of the vehicle body and a microprocessor controller, wherein the microprocessor controller receives signals from the four relative position sensors and determines, responsive thereto, for each tire, a signal indicative of a pressure of air within the tire.