Patent GB-1367999-A (GB)
Title: Electronic taximeter
IPC: G01D4/00
Filed: 1972-12-06
Abstract: 1367999 Electronic taximeters KIENZLE APPARATE GmbH 6 Dec 1972 [21 Jan 1972] 26876/72 Heading G4T In an electronic taximeter, a component 5, which gives a store and calculator 1 tariff instructions as to how the fare is to be built up, is readily replaceable by a different component 5 if a different tariff system is to be adopted. As described, component 5 comprises replaceable circuit boards 22, 23 (also Figs. 2, 2a, not shown) including a number of input leads (e 00 - e n ), which are successively called up over leads a 1 -a 6 , Fig. 4. The input leads and their associated gating &c. arrangements are divided into groups, each of which gives an output over lines i 1 -i 4  when called up. The respective outputs are constants for the particular tariff system and correspond to (a) the value of the minimum fare, (b) the value of a fare increment, a plurality of which will be added to the minimum fare if the time and/or distance corresponding to the minimum fare is exceeded, (c) four pulse-reduction ratios to be applied to the distance pulse train for four respective tariffs, (d) the distance which under tariff I costs the same as the minimum fare and (e) the reduction ratio to be applied to the time pulse train. One of the four available tariffs is selected at a switchboard 4; this enables the corresponding one of the four groups identified at (c). When this enabled group is called up, it delivers the corresponding distance pulse reduction ratio (say 20 : 1) over i 1 -i 4  to a comparator 28, Fig. 4. Simultaneously, over lines a 1 -a 6 , the position of store 9 holding the number of distance pulses received at that time from the distance pulse generator is called up, its content being transferred to comparator 28, and if this number is found to have reached twenty a " corrected " distance pulse is sent to input e 4 , Fig. 5, of circuit 7. Similarly, when the time pulse reduction ratio group-identified at (e) above-is called up and the number (say ten) of time pulses from the time pulse generator held in the appropriate section of store 9 is found to have reached the time pulse reduction ratio (10 : 1) value, a " corrected " time pulse is sent to input e 7  of circuit 7. All " corrected " distance pulses on e 4  get through this circuit 7 to flip-flop FF 2  (direct connection between e 4  and output line e 1 ). If the " corrected " time pulses on e 7  occur at a slower frequency than the " corrected " distance pulses at e 4 , then none of the time pulses get through (each time pulse sets FF 9  to enable AND U 1  for passing the next time pulse, but a distance pulse resets FF 9  before this next time pulse arrives). If, however, the time pulse frequency is the higher, n successive time pulses arriving at e 7  between two successive distance pulses at e 4 , then (n-1) of these time pulses get through. The total number of pulses getting through circuit 7 is thus equal to the number of pulses arriving at circuit 7 from the faster of the two " corrected " pulse trains. Flip-flop FF 2  is one of a number of flip-flops FF 1 -FF 8  forming an input register 6 of a logical array 3 (see also Fig. 1). Each flip-flop acts as a temporary store for one pulse of the quantity to which it is appropriate. FF 7  and FF 8 , for example, receive the time and distance pulses (not yet corrected) from the respective generators over lines e 3  and e 5 . The flip-flops are successively called up at a frequency higher than the frequency of the fastest input to the flip-flops ; i.e. when the taxi is travelling at its maximum speed, the frequency of distance pulses into FF 8  is still less than the call-up frequency, FF 8  therefore never receiving more than one distance pulse between two successive call-ups. The output from any flip-flop found to be set during a call-up cycle is transferred via FF 5  to an appropriate position of the store/ calculator 9/1. The callings-up of the flip-flops, of the sections of store 9, and of the input leads of constant-generating component 5 are all effected over leads a 1 -a 6 , Fig. 4, from a binary counter 25 which is continually triggered by very high frequency pulses over line k 0 . Corresponding sections of the three units are thereby called up simultaneously. A " corrected " time or distance pulse getting through circuit 7 is picked up from FF 2  and added to the running total fare, held in a corresponding section of store 9. The value held in this section is also communicated over lines g 1 -g 4  to an auxiliary store 11, Fig. 1, associated with a fare indicator 14. A control circuit, Fig. 3 (not shown), continually transmits the value held in store 11 to corresponding denomination elements of indicator 14 as a series of pulses of high enough frequency for the indicator to appear to permanently display the running fare. A further indicator 15 displays " extras " value when the taximeter is in " hired " operation, i.e. when indicator 14 is displaying the running fare. When the taxi is not hired, indicator 15 can be used to display the total distance the taxi has travelled or the total distance travelled when in a hired condition or the " extras " or the number of hirings. These values are held in corresponding sections of store 9 and are updated during operation by outputs from flip-flops FF 3 , FF 4 , FF 5 . Flip-flop FF 1  is set when the number of pulses held in store 9 reaches the value corresponding to the minimum fare. Up until this time the fare section of store 9, store 11 and indicator 14 have all stored or displayed this minimum fare, derived from constant-generating component 5. After FF 1  has been set, fare units are added to the minimum fare. Flip-flop FF 6  is set over line e 0  when an automatic tariff change is to be effected.