초록 ▼

A system for obtaining precise inflation to a desired pressure setting of pneumatic tires comprises a pressure transducer which provides an output voltage proportional to its input pressure determines the output frequency of a voltage/frequency converter. The output of the voltage/frequency converte

A system for obtaining precise inflation to a desired pressure setting of pneumatic tires comprises a pressure transducer which provides an output voltage proportional to its input pressure determines the output frequency of a voltage/frequency converter. The output of the voltage/frequency converter is gated into a counter for a set period determined by a timer unit so that in such period the counter assembles a count which is a measure of the sensed pressure. The timer unit is adapted to divide down the local a.c. mains supply frequency so as to derive therefrom discrete timing pulses enabling cyclic operation of the apparatus within a predetermined timing framework. A user has the facility to enter a pressure target into the apparatus and, during each cyclic operation, a comparison is effected between the pressure sensed by the transducer and the set target pressure and, depending upon the outcome of this comparison, a pressure increment or decrement is affectuated as appropriate by operation of an inflate or exhaust valve. Compensation for transducer and/or voltage/frequency converter drift is described, together with variants such as for enabling extra large tires to be rapidly inflated.

대표청구항 ▼

A vehicle tire inflation system comprising: a pressure transducer adapted for connection to a vehicle tire to be responsive to the pressure therewithin for generating a corresponding output signal; converter means responsive to an output signal from said transducer for deriving a periodic signal hav

A vehicle tire inflation system comprising: a pressure transducer adapted for connection to a vehicle tire to be responsive to the pressure therewithin for generating a corresponding output signal; converter means responsive to an output signal from said transducer for deriving a periodic signal having a frequency which is a function of the transducer output signal; counter means coupled to the output of said converter means for counting excursions of the variable frequency signal produced thereby and providing output signals representative of the count accumulated; time control means associated with said counter means for determining periods during which the output of said converter means is counted by said counter means whereby the count accumulated during each of said periods constitutes a measure of the transducer output during the respective period; comparator means for comparing the count assembled in said counter means with a predetermined quantity representative of a desired tire pressure; control means responsive to the result of said comparison for correspondingly adjusting the tire pressure; and the operations of said comparator means and of said control means being arranged to occur at times determined by said time control means.