GB1520136A - Taximeters - Google Patents

Abstract

1520136 Taximeters K SCOTT 19 Aug 1975 34438/75 Heading G4T A taximeter for calculating a fare total from a predetermined combination of distance and time factors comprises an electronic circuit and associated components including an oscillator, in the form of an astable multivibrator 13, adapted to produce said time factor in the form of a constant frequency first electrical pulse train, a transducer adapted to produce said distance factor in the form of a second electrical pulse train, the frequency of which is proportional to the speed of the taxi, modifying means, JK flip-flop 9 and nand gate 12, whereby said first pulse train is modified or controlled by said second pulse train so that the frequency of said first pulse train is modified or controlled to conform to the frequency of said second pulse train when the frequency of said second pulse train exceeds a predetermined unit, activation means, push buttons 35, 36, adapted on operation to activate the taximeter, counting means, counter 29, for counting directly or indirectly the sum of pulses from said first pulse train when said taximeter is actuated and display means 33 adapted to display the fare resulting from the sum of the pulses counted by said counting means in a convenient form. When the second pulse train exceeds the predetermined frequency whereupon more than one pulse of said second pulse train appears between two pulses of said first pulse train, the first of the pulses from said second pulse train setting the flip-flop 9 to prepare the nand gate 12 to pass the second of said pulses from said second pulse train, which pulse triggers oscillator 13 terminating the relaxation period thereof and causing a pulse in the first pulse train to issue from the oscillator conforming with the second pulse from the second pulse train. A rate divider 25, 26 deletes a predetermined proportion of the output pulses of the oscillator so that each remaining pulse represents a unit increase in the indicated fare. The divider is programmable to adapt to varying tariffs. The counting means includes provision to provide a number of pulses corresponding to a preset hireage of flag-fall fee. Preferably the transducer includes a coil 2 to pick up changes in the magnetic field of the speedometer of the taxi, an integrator to smooth the output from the coil and a Schmitt trigger to convert the output from the integrator to distinct pulses.