Abstract:
A portable tire pressure gauge measures a value of tire pressure. The gauge may display the measured value digitally and may output the measured value aurally. The tire pressure gauge may also aurally output a verbal message warning the operator if the measured value approaches a limit value, e.g., if the measured value is below a lower limit or above an upper limit. The limit values, or range of acceptable pressure values, may be set by the user and stored in the gauge. Further, a voice selection switch may be used to selectively turn on and off the voice output warning. Further still, in some examples, the voice warning may be provided in one of multiple foreign languages using the voice selection switch.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a Continuation of U.S. application Ser. No. 10/378,246, filed on Mar. 3, 2003 now U.S. Pat. No. 6,826,508. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a tire pressure gauge. In particular, the invention relates to a tire pressure gauge that digitally displays and aurally outputs the value of pressure measured by it. 
   2. Description of the Related Art 
   There are a variety of conventional tire pressure gauges that digitally display the values of pressure measured by them. A prior art tire pressure gauge displays and aurally outputs the value of pressure measured by it. For example, Japanese Utility Model Registration No. 3,068,608 and U.S. Pat. No. 6,385,554 may be referred to. 
   However, there has been no tire pressure gauge capable of measuring the tire pressure of a bicycle, a car or the like, digitally displaying the measured value in predetermined units of pressure and aurally outputting the value in different languages. 
   In general, the tire pressure of bicycles is high and ranges from about 1 kg/cm 2  to about 8 kg/cm 2 , while the tire pressure of cars is low and about a half of that of bicycles. The air valves particularly of bicycle tires differ in size between the American and French types and among different countries. Accordingly, various tire pressure gauges are required for different valve sizes and different pressure ranges. 
   Various types of bicycle tires and car tires have different ranges of optimum pressure. In general, if a vehicle runs with its tires low in pressure, both sides of the outer peripheral surface of each tire wear out due to their friction against the road surface. This affects the life of the tire. In particular, if a car runs at high speed with its tires low in pressure, they heat up to dangerous temperatures. If a vehicle runs with its tires too high in pressure, only the midsection of the peripheral surface of each tire contacts with the road surface and abnormally wears out. 
   Accordingly, different ranges of optimum tire pressure are set for bicycles and cars, which are vehicles having tires. The tire pressure of each vehicle having tires needs to be checked at regular intervals according to the condition under which the vehicle is used. 
   Recent industrial globalization causes many cars and bicycles made in foreign countries to be imported. Some tire pressure gauges are imported, and others are exported. In general, tire pressure gauges for use in each country display values of tire pressure in the units of pressure used there, and aurally output them in the language or one of the languages of the country. The tire pressure gauges that aurally output values of pressure in only one language are inconvenient in a country where two or more languages are spoken. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing problems, the object of the present invention is to provide a portable tire pressure gauge for measuring a value of tire pressure, the gauge being able to display the measured value digitally and selectively in one of different units of pressure and output the measured value aurally and selectively in one of different languages. 
   According to a first aspect of the present invention, there is provided a tire pressure gauge for measuring a value of tire pressure, the gauge comprising a display for displaying the measured value, an audio output unit for aurally outputting the measured value in one of different languages, and a power supply for measurement and display. This gauge can output the measured value of tire pressure aurally in a desired language and be operated even by a person having bad eyes. 
   The different languages may be the language of a country and a first foreign language in the country. The gauge may further comprise a voice output switch for switching on or off voice output and a language selection switch for selecting one of these two languages. The gauge can output the measured value aurally and selectively in one of the language of the country and the first foreign language, which many people in the country speak or understand. 
   The language of the country and the first foreign language may be English and Spanish, respectively, which many people in the United States understand. 
   The audio output unit may output the measured value of tire pressure as displayed on the display. If the measured value approaches a limit value stored in an arithmetic circuitry, this output unit may also output an audio warning. In this case, if the measured value is so low that the tire needs to be supplied with air, the tire pressure gauge can output an audio warning, which reminds the gauge user to supply the tire with air. 
   If the power supply is a solar battery, there is no need to carry a battery about together with the tire pressure gauge. This makes the gauge portable. 
   According to a second aspect of the present invention, there is provided a tire pressure gauge comprising a chuck for engaging with the air valve of a tire, a detector for detecting a value of tire pressure, a display for displaying the detected value, a unit selection switch for selecting the units of pressure in which the detected value is displayed, an arithmetic circuitry for converting the detected value into a value in the selected units, an audio output unit for aurally outputting the detected value in one of different languages, and a power supply for measurement and display. This gauge can measure tire pressure in various units of pressure. 
   The display of this gauge may be digital. The gauge may further comprise an illuminator for illuminating the digital display to make sure that the detected value of tire pressure is visible. 
   The units of pressure may be “psi”, “bar”, “kg/cm 2 ” or “kPa” so that the detected value of tire pressure can be displayed in the units of pressure that the gauge user understands most easily. 
   The different languages in which this gauge can aurally output the detected value may be the language of a country and a first foreign language in the country. The gauge may further comprise a voice output switch for switching on or off voice output and a language selection switch for selecting one of these two languages. The gauge can output the detected value aurally and selectively in one of the language of the country and the first foreign language, which many people in the country speak. The gauge can also output the value aurally in the units of pressure that the gauge user understands most easily. This enables many people in the country to understand the gauge. 
   The language of the country and the first foreign language may be English and Spanish, respectively. This enables the gauge to output the detected value of tire pressure in the units of pressure that the people living in the United States understand most easily. The audio output unit may output the detected value of tire pressure as displayed on the display. If the detected value approaches a limit value stored in the arithmetic circuitry, this output unit may also output an audio warning. In this case, if the detected value is so low that the tire needs to be supplied with air, the tire pressure gauge can output an audio warning in the units of pressure that the gauge user understands most easily. The warning reminds the user to supply the tire with air. 
   In accordance with another example of the present invention, there is provided a tire pressure gauge for measuring a value of a tire pressure, where the gauge may aurally output a message warning the operator if the measured value approaches a predetermined limit value. For example, if the measured value is below a lower limit value, the message may speak that the tire pressure is too low. Likewise, if the measured value is higher than the upper limit value, the gauge may speak a warning that the tire pressure is too high. The value or values at which the operator is warned may be set by the user. In some examples, a voice selection switch may be turned to select voice output or no voice output. In some further examples, the voice selection switch may also be used to select a voice output in one of multiple languages, such as a first foreign language or a second foreign language. 
   In accordance with another example, provided is a method of indicating tire pressure, the method comprising: detecting a tire pressure from a chuck engageable with an air valve of a tire; measuring the tire pressure from the detection of the tire pressure; displaying the measured tire pressure; determining if the measured tire pressure is outside a limit value; and aurally outputting a warning voice message, if the measured tire pressure is outside the limit value. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1(   a ) is a side view of a tire pressure gauge according to a first embodiment of the present invention. 
       FIG. 1(   b ) is a back view of the gauge shown in  FIG. 1(   a ). 
       FIG. 2(   a ) is a back view of a tire pressure gauge according to a second embodiment of the present invention. 
       FIG. 2(   b ) is a side view of the gauge shown in  FIG. 2(   a ). 
       FIG. 3  is a control block diagram of the gauge shown in  FIGS. 1(   a ) and  1 ( b ). 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Embodiments of the present invention are described below with reference to the accompanying drawings. 
     FIGS. 1(   a ) and  1 ( b ) show a tire pressure gauge  1 , which consists of a main body  1   a  in the form of a rectangular parallelepiped and an inclined head  1   b  at the top of the body  1   a . The head  1   b  has a chuck  2  that can engage with the air valve of a tire. 
   As shown in  FIG. 1(   a ), the gauge body  1   a  is fitted with a liquid crystal display  3 , a power/unit switch  4 , a solar battery  5  and a voice selection switch  7  on its left side. A lower portion of the gauge body  1   a  is fitted with an audio output unit  6 . 
   The gauge  1  is lightweight, small, long and narrow or slender so as to be easy to hold in one hand. It is accordingly easy to measure the pressure of a tire by holding the gauge body  1   a  in one hand and forcing the chuck  2  into engagement with the air valve of the tire. The edges and corners of the gauge  1  are rounded so that it can be manipulated easily without injuring the hand holding it. 
   The display  3  digitally displays the value of pressure measured by the gauge  1 . The power/unit switch  4  can be pushed to switch the unit of pressure to “psi”, “bar”, “kg/cm 2 ” or “kPa” in that order. The switching order might be another order. The gauge  1  can measure every psi, every 0.05 bar, every 0.05 kg/cm 2  or every 5 kPa of pressure. The power/unit switch  4  can also be pushed to switch on or off the gauge  1 . 
   The solar battery  5 , which is the power supply for driving the gauge  1 , supplies power for pressure measurement, output display and voice output. 
   The power supply for measurement and display might alternatively be a dry battery or another portable battery. However, a solar battery is suitable as the power supply for the gauge  1 , because this battery does not need to be replaced, and because the gauge  1  is often used outdoors. 
   The voice selection switch  7  can be turned to select no voice output, voice output in a first language or voice output in a second language. If the gauge  1  is made for use in a country, the first language for the gauge may be the official language of the country. In this case, the second language for the gauge  1  may be the first foreign language spoken most commonly in the country. For example, if the country is Japan or the United States, the first language may be Japanese or English, respectively, and the second language may be English or Spanish, respectively. Spanish is spoken by Central American immigrants in the United States. The gauge  1  may store the messages specified by a user in two languages. 
   If the voice selection switch  7  is turned to select voice output in one of the two languages, the gauge  1  aurally outputs, in the selected units of pressure, the value of pressure measured by it. It is preferable that, if the measured value approaches the predetermined lower limit value, the gauge  1  should aurally output a message warning the operator after the value is output. The message may say that the pressure is too low. Likewise, if the measured value is higher than the upper limit value, the gauge  1  might aurally warn that the pressure is too high. The gauge  1  has an IC memory, where the voice data for the messages may be recorded. If the measured value is within sufficiently safe range, only this value may be output aurally. The value or values at which the operator is warned may be set either when the gauge  1  is produced or at the option of the user. 
   In particular, because the United States has a large area and many highways and roads kept in good repair, cars are usually used as traffic means in the States. In the States, because many drivers usually keep their cars in good condition by themselves, they want tire pressure gauges easy to use. 
   Accordingly, the gauge  1  has voice output in English and Spanish as the first and second languages respectively. The voice selection switch  7  has a knob  7   a , a position E, a position S and a neutral position between the positions E and S. The knob  7   a  can be turned to the position E, the position S or the neutral position for English, Spanish or no voice output respectively. 
   The unit of pressure psi is used in the United States and other countries where the units “yard” and “pound” are used. The units of pressure “bar”, “kg/cm 2 ” and “kPa” are used in metric countries, where the metric system is used. 
   While the gauge  1  is measuring the pressure of a tire, with the chuck  2  forced into engagement with the air valve of the tire, the chuck  2  may be sealed with an elastic member (not shown) against air leakage. 
     FIGS. 2(   a ) and  2 ( b ) show another tire pressure gauge  1 A, which includes a chuck  2 A, a liquid crystal display  3  and a power/unit switch  4 . The chuck  2 A can engage with the air valve of a bicycle tire as well as the air valve of a car tire. The display  3  displays the value of pressure measured by the gauge  1 A. The switch  4  can be pushed to switch the unit of pressure. The body of the gauge  1 A has a gently convex front surface  8  and a gently concave back surface  9  so that the body can be held easily in hand. 
   As is the case with the gauge  1 , the gauge  1 A is fitted with a solar battery  5 , an audio output unit  6  and a voice selection switch  7 A. 
   The voice selection switch  7 A can be pushed to select voice output in a first language, voice output in a second language or no voice output. 
   In general, the air valves of bicycles are classified into the American and French types. It is possible to use the gauge  1 A for either of the types by merely changing the assembly of one or more parts of the chuck  2 A. 
   Bicycles have a higher range of tire pressure than cars. The gauge  1 A can measure up to 10 kg/cm 2 , under which the tire pressure of bicycles ranges. The gauge  1 A can, with sufficient accuracy, measure even a range from 2 kg/cm 2  to 3 kg/cm 2 , which is the range of car tire pressure. Accordingly, the gauge  1 A is common to bicycles and cars. 
     FIG. 3  is a control block diagram of the gauge  1 , which includes an electronic board  20 . The board  20  is a unit including a power controller  21  for on-off control of the power supply, an arithmetic circuitry  22 , a display controller  23  and an internal oscillator  24 . The arithmetic circuitry  22  computes, into a value in the units of pressure selected with the switch  4 , the electric signal representing the vibration based on the tire pressure detected at the chuck  2 . The display controller  23  controls the liquid crystal display  3 . By using the electronic board  20 , it is possible to accurately measure a range of tire pressure up to 10 kg/cm 2  and display the measured value in the various units of pressure. 
   The solar battery  5  supplies power through the power controller  21  to the arithmetic circuitry  22 , the display controller  23  and the internal oscillator  24 . The display  3  displays the measured value in the units of pressure selected with the power/unit switch  4 . The audio output unit  6  speaks the displayed value, which may be followed by the warning message, in the language selected with the voice selection switch  7 . 
   The display  3  can hold and display the peak value of tire pressure measured by the gauge  1 . After the peak value is measured with the chuck  2  forced into engagement with the air valve of a tire, the displayed value can be confirmed on the display  3 . If the power/unit switch  4  is pressed for a predetermined time, which may be three seconds, or longer, the displayed value switches automatically to another unit of pressure. The internal oscillator  24  operates to measure the predetermined time. 
   Another function of the gauges  1  and  1 A is zero point correction, which is performed at the same time that the power/unit switch  4  of each gauge is pressed after the gauge is switched on. 
   A lower limit and an upper limit of tire pressure are set in each of the gauges  1  and  1 A. If the gauge  1  or  1 A measures a tire pressure under the associated lower limit or over the associated upper limit, the gauge sounds a buzzer, without voice output selected. 
   Because the power supply of each gauge  1  or  1 A is a solar battery, the gauge is portable and easy to carry about for cycling or a drive, and it is possible to check the tire pressure with the gauge as the need arises. This makes it possible to enjoy safe cycling or a safe drive. 
   The display  3  of each gauge  1  or  1 A is fitted with an illuminator  3   a , which may be an LED or an electric light bulb, for illuminating it. The gauge  1  or  1 A includes a circuit that, when the associated chuck  2  or  2 A is forced into engagement with the air valve of a tire, detects the pressure of the tire and applies an electric current to the illuminator  3   a  so as to light this illuminator. The illuminator  3   a  makes it easy to read the value on the display  3  even at night or in a dark place. If the illuminator  3   a  is an LED, it consumes less power and is economical.