Patent ID: 7607346

Claim:
A tire pressure indicator (TPI) that functions in combination with a vehicle tire stem that has a conventional Schrader-type tire-valve core removed and that has an upper end that includes a set of outer threads and a lower end that includes a spring retainer, said TPI comprising: A. a valve core that is designed to be inserted into the vacated vehicle tire stem, said valve core comprising: a) a valve plug having an upward-extending cavity that terminates with an upper surface having a plug shaft bore, a valve stem interfacing surface and a lower surface, b) a plunger housing having: (1) an upper surface that interfaces with the lower surface of said valve plug and a plunger shaft bore that is in alignment with the plug shaft bore, (2) a lower surface having attached thereto a housing base having an upper surface, a lower surface, and an air-passage bore, c) a diaphragm located within said plunger housing and having an upper surface and a lower surface wherein the lower surface interfaces with the upper surface of the housing base, d) an upper spring that is located between the upper surface of said diaphragm and the upper surface of said plunger housing, e) a plunger shaft that extends through the plug shaft bore and through the plunger shaft bore, wherein said plunger shaft having an upper end and a lower end that interfaces with the upper surface of said diaphragm, f) a compressive element located between the lower surface of the base and the spring retainer on the vehicle tire stem, B. a control cap that interfaces with the valve plug and that attaches to the upper end of the vehicle valve stem, C. a tire-pressure transmitting unit (TPTU) that is enclosed within said control cap, said TPTU having means for receiving and processing a high pressure signal and a low pressure signal, and producing and transmitting an encoded R.F. signal that corresponds to either an encoded high pressure signal or an encoded low pressure signal, D. a tire-pressure monitoring unit (TPMU) that is located remotely from said TPTU, said TPMU having means for receiving and processing the encoded R.F. signal from said TPTU and means for producing: a) a decoded high pressure signal that illuminates an LED (DS 3 ) in a first color, or b) a decoded low pressure signal that illuminates an LED (DS 4 ) in a second color, and E. means for preventing said TPTU from transmitting false high or low tire pressure signals that result from changes in the ambient temperature and/or normal tire temperature fluctuations that vary from a base temperature that corresponds to a preset tire pressure.