US3858030A

US3858030A - Taximeters

Info

Publication number: US3858030A
Application number: US00357780A
Authority: US
Inventors: F Hart
Original assignee: MARTIN TAXIMETERS Pty Ltd
Current assignee: MARTIN TAXIMETERS Pty Ltd
Priority date: 1972-05-10
Filing date: 1973-05-07
Publication date: 1974-12-31
Anticipated expiration: 1991-12-31
Also published as: AU468720B2; DE2322590A1; GB1422661A; JPS49117083A; AU5549573A

Abstract

A taximeter having a mechanical mechanism which operates a control element to rotate the control element at a rate proportional to the distance travelled by a taxi, if the speed of the taxi is greater than a predetermined value, or otherwise to rotate the element at a constant rate, the element having associated therewith a transducer for generating a pulse train of frequency corresponding to the speed of rotation of the element and electronic counter and display means being provided to count the pulses of the pulse train and to display a taxi fare in accordance with a count of the pulses over the time of a taxi journey.

Description

United State S Patent [1 1 Hart [ Dec. 31, 1974 [54] TAXIMETERS 3,553,442 1/1971 Weisbart 235/92 3,703,985 11 1972 B 235 30 R [75] Invent: Franc'sghseph North Balwyn, 3,764,782 10i1973 5522352115 et al 23si30 R Australia [73] Assignee: Martin Taximeters (Aust.) Pty., Ltd. m y EXamiI1r-RiChard Wilkinson Assistant Examiner-Vit W. Miska [22] Filed: May 1973 Attorney, Agent, or Firm-McGlew and Tuttle [2]] Appl. No.: 357,780

[57] ABSTRACT [30] Foreign Appli atio P i it D t A taximeter having a mechanical mechanism which May 10 1972 Australia 8917/72 operates a control element to rotate the control element at a rate proportional to the distance travelled 521 US. Cl. .L .235/30 R 235/45 by a taxi if the Speed of the mi is greater than a P 51 Int. Cl. G07 b 13/00 determined value, or Otherwise to rotate the element 5 Field of Search 23523012 33 45 at a constant rate, the element having associated therewith a transducer for generating a pulse train of [56] References Cited frequency corresponding to the speed of rotation of the element and electronic counter and display means UNITED STATES PATENTS being provided to count the pulses of the pulse train 3,157,352 11/1964 Caywood 235/45 and to display a taxi fare in accordance with a Count Z: :1 of the pulses over the time of a taxi journey 3:512:70o 5/l972 235/30 R 14 Claims, 5 Drawing Figures Ami/W!!! fiffl/ Wff W12 flfJ/f Wl'fil/f/ {My Mf/fl/fl ,lfl/jfffff/ 17 aw zb w 14 1mm fiwz/wfz/wf w 43 w Vafillll Hit 3 \iiii iiti WWI/M! iii flaw /7Vf fl/V/ff KIM 7Z7 [lfl/V/Y [flfl/V/Z [WM f L L /2- l L l W4 W1 W1 fif/Wfif/ JIM/[1 fif/dfif/ flff/fl/F i i i L74 2 i? [7 37 A7 a?! H 1 H -?7 i lid/Z6 'f/M/f/fiV/Z [[A [f M J/f/Al/ fi/J/[fl fi/JP/l/ SHEET 2 [1F 3 at u L L $2 W4 W W4 mwm/ FIG. 4. w w i 0 i i a 24 I2 BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relates to taxi meters.

2. Description of Prior Art Taxi meters of one kind in common use utilise a mechanical device which has a rotatable member which, when the vehicle is stationary or moving at less than a predetermined speed, is driven at a preselected rate but which is coupled, when the vehicle is moving at more than the predtermined speed, to be driven at a rate which is proportional to the vehicle speed. Suitable mechanical means is provided, operated by this member to operate a mechanical farecharge recorder which, when the vehicle is stationary or moving at less than the predetermined speed, records a fare charge which is proportional to time and when the vehicle is moving at at more than the predetermined speed, records a distance travelled fare charge.

Taxi meters of the above kind, while being generally satisfactory in use require adjustment and continual maintenance in order to preserve their accuracy under operating conditions. This is particularly necessary in respect of the fare charge recorder. Proposals have been made to avoid this problem by employing wholly electronic devices but these tend to introduce further difficulties in that they are oftenprone to electrical interference which causes wrong fare computations'An object of the invention is therefore to provide a taxi meter which avoids, at least in part, the above difficulties.

BRIEF SUMMARY OF THE INVENTION According to the present invention there is provided a taxi meter having a rotatable control element, means for driving said element at a constant preselected rate, means for driving the element at a rate dependent upon the speed of a vehicle to which the taxi meter is affixed and clutch means for selectively coupling either of said drive means to said element so that the element is driven, when the vehicle is moving at more than a preselected speed, by said second means, and when the vehicle is stationary .or moving at less than said preselected speed, by said first means, said device further including transducer means coupled to said element for producing an electrical signal pulse train representative of the speed of rotation of the element and electronic counter and display means for counting the pulses of said train and displaying a fare value proportional to the number of pulses counted. Preferably the lastmentioned means includes pulse multiplier means for multiplying the pulses by a preselected value proportional to a preselected fare rate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING:

One embodiment of the invention is now described in detail with reference to the accompanying drawing, in which:

FIG. 1 is a partly schematic view of mechanical parts of the taxi meter;

FIG. 2 is across-section on the line 2-2 in FIG. 1;

FIG. 3 is a diagram illustrating the manner of organisation of electronic counter and display means forming part of the taximeter;

FIG. 4 is an electrical circuit diagram of part of the counter and display means of FIG. 3; and

FIG. 5 is an electrical circuit diagram of another part of the counter and display means of FIG. 3.

DETAIL DESCRIPTION Referring firstly to FIG. 1, the taxi meter includes a mechanical device 11 having a gear train 50 which is coupled to the speedometer drive cable from the engine gear box of a taxi 52, to be driven by the gear box.

The gear train 50 has an output shaft 54 which is driven by the gear train at a rate proportional to the speed at which the vehicle is travelling. An electric motor 56 drives a second gear train 58, the output shaft 60 of gear train 58 being driven at a constant speed.

Shafts

54, 60 are coupled to a clutch 62 which is itself coupled to drive a third gear train 64 from a gear 62a on the clutch. Gear train 64, in turn, drives an output shaft 66 of device 11 to which is attached a five-lobe cam 68, of a transducer 12.

Clutch 62 is of a kind operating to drive gear 62a at a speed equal to the speed of whichever one of

shafts

54 and 60 is rotating at the faster rate.

The drive from motor 56 is such as to tend to drive output shaft 66 at a constant speed of about one revolution every 2 minutes whereas the drive from the speed ometer cable is such as to tend to drive the shaft at a speed approximately two revolutions to the mile travelled by the taxi. Accordingly, when the taxi is stationary, the output shaft 66 of device 11 will be turned at one revolution every 2 minutes, but when the vehicle speed reaches a predetermined level it will instead be driven at a rate of approximately two revolutions to the mile.

Transducer 12 includes a cam follower 70 of spring steel which is attached at one end 70a to a fixed part (not shown) of the taximeter so that the free end 70b is biased resiliently radially inwardly of the cam follower.

An operating arm 72 also of spring steel is attached at one end 720 to a fixed part of the taxi meter and the free end carries a roller 74 which is biased against cam follower 70. An actuating member 76 ofa micro switch 78 is positioned adjacent to arm 72. As shaft 66 turns cam follower 70 is flexed upwardly and then downwardly, as viewed in FIG. 2, each time end 70b thereof passes over a lobe 68a of cam 68. Roller 74 thus is also moved upwardly and downwardly, because the roller is biased against the cam follower, so that up and down flexing of arm 72 results. This flexing of arm 72 causes the arm to press against member 76 to operate micro switch 78 each time the end 70b of the cam follower moves downwardly. Micro switch 78 is thus operated five times for every revolution of shaft 66.

Switch 78 is of the single pole double throw type and is coupled into an electric circuit 80 (FIG. 5) forming part of transducer 12. Thus, a movable contact 7811 of the switch is connected to an earthed terminal of an electric power supply (not shown) by a conductor 82.

pulses being proportional to the speed of rotation of output shaft 66.

Output lines 88, 90 from circuit 80 are connected to a pulse shaping circuit 13. This includes a flip-flop 92 having two

inverters

94, 96 which receive input pulses on lines 88, 90 and produce corresponding, shaped, pulses on output line 98, these shaped pulses having clean leading and trailing edges suitable for operation of subsequent integers of the taxi meter. Line 98 is coupled to the base of a transistor 100 which is connected into a switching circuit 102. Circuit 102 provides a pulse train output on an output line 104 which is connected to a pulse multiplier 14.

Output line 104 couples to a first differentiating circuit 110 of pulse multiplier 14. This circuit includes a capacitor 112 coupled, at one side, to line 104 and a resistor 114 connected between the other side of the capacitor and the earthed terminal of the power supply. Output from circuit 110 is taken on a conductor 116 coupled to the junction between the capacitor and resistor. conductor 116 is connected to the input terminal of an inverter 118, and the output terminal of this inverter is coupled, via a conductor 120 and a resistor 122 to the supply rail of the power supply. Differentiating circuit 110 operates to render pulses from circuit 13 of constant short duration. In this respect it will be appreciated that pulses generated by switch 78 will be of duration equal to the inverse of the pulse frequency, and will thus vary in duration over a considerable range as the speed of taxi 52 changes. This variation in pulse duration, which is considerable, is removed by differentiating circuit 110. Inverter 118 and resistor 122 are connected to produce, from circuit 110, output pulses on conductor 120. For every pulse applied on line 104, then, there is generated on conductor 120, a single pulse of constant duration.

Multiplier 14 includes four further differentiating

cir cuits

124, 126, 128, 130. Each of these circuits is identical to circuit 110. These are coupled to line 104, via

separate delay circuits

132, 134, 136, 138, which each comprise a capacitor 140 coupled at one end to line 104 and a resistor 142 connected between the other side of the capacitor and the earthed terminal of the power supply. Outputs from the

delay circuits

132, 134, 136, 138 are taken, via

respective inverters

142, 144, 146. 148 and applied to respective ones of the differentiating

circuits

124, 126, 128, 130. Outputs from the differentiating cirucits are applied to respective

further inverters

150, 152, 154, 156.

Conductors

158, 160, 162, 164 couple outputs from these inverters to a common conductor 166 which is coupled to conductor 120 and to resistor 122.

The

delay circuits

132, 134, 136, 138 have progressive delays so arranged that a pulse applied to these on line 104 will generate on each

conductor

158, 160, 162, 164 a separate pulse of duration equal to that of a pulse produced on conductor 120, but with progressively increasing time delays after the pulse on line 120 appears. As described in detail hereinafter

conductors

158, 160, 162, 164 can be selectively interrupted by assuming that not interruption is effected pulse multiplier 14 produces on conductor 166, for each pulse applied on line 104, a series of five equitime spaced pulses of short duration.

Conductor 166 of pulse multiplier 14 is connected via a line 108 to a units decade counter 17. This operates to provide, on output lines 170, a binary coded output advancing one count for every pulse applied to the counter. This output is applied to a decoder 22 connected to drive a seven segment cents display device 27.

Display device 27 is thus operated to successively display numerals O to 9 in repeated sequences, the numeral displayed advancing one count for each pulse applied to counter 17. At each tenth count a pulse is delivered on an output line 172 from counter 17.

Three further decade counters 18, 19 and 21 are provided. Counter 18 receives pulses on line 172 and on each tenth pulse delivers an output on an output line 176 thereof. Counter 19 receives pulses on line 176 and, at each tenth pulse, delivers a single pulse on an output line 178 therefrom. Counter 21 receives input pulses from line 178. The

counters

18, 19 and 21 have

output lines

174, 180, 182 which couple to

respective decoders

23, 24 and 26. The

counters

18, 19, 21 operate in an analogous manner to counter 17 producing binary coded outputs on

lines

174, 180, 182 which advance one count for each pulse applied thereto. The

decoders

23, 24, 27 likewise operate in an analogous manner to decoder 22, each advancing the displayed numeral of an associated

display device

28, 29, 31 on' count for each pulse applied to the

respective counter

18, 19 or 21.

Counters

18, 19, 21 comprise, respectively, a tens of cents counter, a dollars counter and a tens of dollars counter.

The taxi meter is operated by a switch (not shown) which operates to couple the power supply to the electrical parts of the meter. This switch might, for example, be coupled to the usual taxi meter HlRE and NOT FOR HIRE indicator mechanism. When switching on is effected, it is, of course, necessary to operate the display devices 27 to 31 so that these display the correct flag fall. This is effected by a preset and reset pulse generator 15 in conjunction with a pre set code circuit 32.

Generator 15 includes a transistor 200 having its collector coupled to the power supply rail via a resistor 202, and its emitter coupled to earth terminal of the power supply via a resistor 204. The base ofthe transistor is coupled, via a resistor 206, to the junction 215 between a series connector resistor 208 and an earthed capacitor 210. Resistor 208 and capacitor 210 are connected between the supply rail and earthed terminal of the power supply. Two inverters 212, 214 are coupled respectively from the collector and emitter of transistor 200 to a common line 216, the connection between the emitter and inverter 214 being via a resistor 218.

Line 216 is coupled through two parallel differentiating and time delay circuits 220, 222, each comprising a capacitor and resistor, to separate respective inverters 224, 226. The output from inverter 224 is connected via an output line 228 to conductor 166 of pulse multiplier 14 and thus to line 108. The output terminal of inverter 226 is connected to a conductor 230 and also, via a further inverter 232, to a conductor 234.

When the operating switch for the taxi meter is operated, the power supply is applied across the earthed terminal thereof and the supply rail thereof. This causes the voltage at the junction 215 to rise at a predetermined rate. The transistor 200 and inverters 212, 214 operate together as a Schmitt trigger circuit which rapidly switches transistor 200 when the voltage at jucntion 215 reaches a sufficient value. This thus causes a rapid rise of the voltage on line 216, the rise occurring after a time delay from switching on of the taxi meter. The time delay is made sufficient to ensure that other parts of the electric circuit are in stable operation at the time of voltage increase on line 216. Circuit 220 and inverter 224 operate to provide, from this voltage increase, an output pulse which is applied to line 108 via conductor 228. Likewise,

inverters

226 and 232 operate in conjunction with circuit 222to provide output pulses on

lines

230 and 234.

Line 234 is coupled to

decade counter

19, 21 so that the pulse applied thereon resets these and the associated

display devices

29, 31 to zero. The pulses applied on

lines

108 and 230 from generator operate to preset the decade counters l7, l8 and the associated display devices so that

display devices

17, 18 display a preselected initial fare charge. This initial fare charge is selected by means of the preset code circuit 32 which operates to bridge selected ones of four binary-code input terminals 240 of each counter 17, 18 to the line 230. The bridging is arranged such that the pulse on line 230 is applied to the selected terminals 240 so as to represent, in binary code, the numerals desired to be displayed in the

display devices

27, 28.

Circuit 32 is formed as a plug-in printed circuit and also includes plug connections which co-operate to completeonly desired ones of the

conductors

158, 160, 162, 164. It is thus possible to easily change the desired initial presetting of counters l7, l8 and to change the number of pulses appearing on line 108, for each pulse applied to pulse multipler 14, by unplugging circuit 32 and replacing it with another having a desired initial display coding for terminals 240 and a desired selection of pulse miltiplication.

In use of the taxi meter, pulses from transducer 12 are applied to pulse shaper 13 as a pulse train which, when the taxi is at standstill, is at a predetermined constant rate and, when the taxi is moving at more than a predetermined speed, are at a rate proportional to distance travelled. These pulses are shaped in pulse shaper l3, multiplied in multiplier 14 as desired by one, two, three, four or five according to the selected completion of

conductors

158, 160, 162, 164 and then passed to the counters to operate the display devices to record the taxi fare. The selection of a desired pulse multiplication rate is made together with selection of gear ratios in

gear trains

50, 58, 64 to give a desired rate of fare changing.

The taxi meter has been found to be reliable in use because the initial pulse train representing the fare is not generated in a manner which is prone to electrical interference as is the case when the mechanical device 11 in replaced by an electronic pulse generator. On the other hand, the electronic part of the apparatus is free from the aforementioned disadvantages of mechanical computation mechanisms and requires little maintenance is use. The electrical part of the meter can be constructed using readily available components. For example, counters 17, 18 may comprise commercially available integrated circuits type 9310 whilst

counters

19, 21 may comprise integrated circuits type 7490.

The described taxi meter has been advanced merely by way of explanation and many modifications may be made thereto with the spirit and scope of the appended claims.

We claim;

1. A taxi meter having a rotatable control element, means for driving said element at a constant preselected rate, means for driving the element at a rate dependent upon the speed of a vehicle to which the taxi meter is affixed and clutch means for selectively coupling either of said drive means to said element so that the element is driven, when the vehicle is moving at more than a preselected speed, by said second means, and when the vehicle is stationary or moving at less than said preselected speed, by said first means, said device further including transducer means coupled to said element for producing an electrical signal pulse train representative of the speed of rotation of the element and electronic counter and display means for counting the pulses of said train and displaying a fare value proportional to the number of pulses counted.

2. A taxi meter as claimed in claim 1, wherein said counter and display means includes pulse multiplier means for multiplying the pulses of said pulse train by a preselected value proportional to a preselected fare rate.

3. A taxi meter as claimed in claim 2, wherein said pulse multiplier means includes a plurality of pulse generators each operable to produce, from a pulse applied to the pulse multiplier means, a separate single pulse, the pulse generator means including time delay means whereby the said pulses generated thereby are generated as a sequence of equi-time-spaced pulses upon each application of a pulse to said pulse multiplier means.

4. A taxi meter as claimed in claim 3, wherein coupling means is provided for selectively coupling at least some of said pulse generators to an output of said pulse multiplier means.

5. A taxi meter as claimed in claim 4, wherein said coupling means comprises a removable plug-in circuit board having printed thereon particular electrical connections providing said selective coupling, whereby said pulse multiplier means can be adapted for different multiplication rates by replacement of the circuit board.

6. A taxi meter as claimed in claim 1, wherein said transducer means includes a switch coupled to cam follower means, said cam follower means including a lobed cam affixed to said element whereby the switch is operated at least once for each revolution of said element.

7. A taxi meter as claimed in claim 6, wherein said switch is a double-throw switch having a fixed contact which alternates between connection to two fixed contacts as the switch is operated, said fixed contacts being coupled to one terminal of an electrical power supply and the fixed contacts being affixed to the other terminal thereof, whereby the electrical potential of the fixed contacts alternates as operation of the switch is effected, whereby to generate said train of pulses.

8. A taxi meter as claimed in claim 7, including a pulse shaping circuit interconnected between said transducer means and said pulse multiplier means, said pulse shaping circuit including an electrical switching circuit which receives outputs from said fixed switch contacts whereby the pulses of said pulse train are shaped by alternate switching of said switching circuit, and are of duration substantially equal to the time of switching of the switch at either of its positions.

9. A taxi meter as claimed in claim 8 wherein said pulse multiplier means includes differentiating means by said pulse multiplier means is substantially less than the duration of pulses applied thereto.

10. A taxi meter as claimed in claim 9 including preset and reset pulse generator means which operate to reset said counter and display means when the taxi meter is switched on.

11. A taxi meter as claimed in claim 10, wherein said preset and reset pulse generator means includes preselector means for causing at least one flagfall counter of said counter and display means to operate associated display means of the counter and display means to display a predetermined fare indication upon switching on of the taxi meter.

12. A taxi meter as claimed in claim 11, wherein at least one of the said counters is provided with binary coded input terminals whichcan be selectively coupled to a presetting pulse generator indluded in said preset and reset pulse generator means to cause said at least one flagfall counter to generate an output resulting in display, in the associated display means, of said predetermined fare indication.

13. A taxi meter as claimed in claim 12, wherein said presetting pulse generator comprises means to generate a preset pulse, as the taxi meter is turned on, and said preselector means includes electric connector means on a removable plug-in board which couples selected ones of said binary coded input terminals to receive said preset pulse.

14. A taxi meter as claimed in claim 13 wherein said removable plug-in boards are formed as a single unit. =k

Claims

9. A taxi meter as claimed in claim 8 wherein said pulse multiplier means includes differentiating means one such means being associated with each pulse generator means whereby the duration of pulses produced by said pulse multiplier means is substantially less than the duration of pulses applied thereto.

12. A taxi meter as claimed in claim 11, wherein at least one of the said counters is provided with binary coded input terminals which can be selectively coupled to a presetting pulse generator indluded in said preset and reset pulse generator means to cause said at least one flagfall counter to generate an output resulting in display, in the associated display means, of said predetermined fare indication.

14. A taxi meter as claimed in claim 13 wherein said removable plug-in boards are formed as a single unit.