The Anatomy of the Picard Taximeter.
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A Description of the Mechanism of a Successful French Appliance for Mileage Recording or Time Registration.
The apparatus which, in France, is known as the " Compteur le Francais, Systeme Picard," and is manufactured and marketed by M. R. Picard, of 12, Rue Alfred-de-Vigny, Paris, is a taximeter which presents many interesting features, both in the ingenuity of its mechanical details, and in the arrangement of its interconnected component parts. Special interest attaches to this particular type of instrument, because it was the first fare-registering machine to be officially recognised by the municipal authorities in Paris, and, as this took place so far back as the year iSgo, the designer and manufacturer of the Picard machine can claim to have been one of the first, if not the first, to succeed in producing a thoroughly practicable and reliable combination. At the present time, more than two thousand of these appliances are in constant employment in the streets of Paris, and the machine, in its latest form, has been approved by the licensing authorities of the cities of London, Paris, Marseilles, Rouen, IIavre, Tours, Caen, Nantes, Brussels, Kieff, Cairo and many other of the largest towns abroad ; the Picard taximeter, moreover, is in actual service in most of these places. Scotland Yard authorities have given their sanction to the employment of the appliance, in London, on two-wheeled and four-wheeled horse-drawn and on automobile types of hackney carriages.
Inclined Indicator Window.
The general external appearance of the taximeter is clearly portrayed in the two photographs of the complete machine which we reproduce herewith. It will be at once remarked that the Picard differs from other machines of this character with which readers are
familiar, because of its long flat shape ; but this useful characteristic has in many instances enabled the makers— notably on some types of hansoms and growlers—so to dispose the face of the indicator, that it may be read by a pas senger from the inside of the vehicle to which it is fixed, without the necessity of his having to crane his neck at an uncomfortable angle in order to enable him to read the dial. The figures on some types of taximeters are too small, and the appliances are not always fixed at the best angle.
Examination of the illustration below will reveal the fact that the indications of the payable charges are made through a window which is inclined to the vertical, in order that the figures may be read with equal facility both by the driver and by the passenger. It will also be noticed that the four totalling counters are all conveniently grouped together at the bottom of the back of the casing, where they can be very easily and quickly inspected.
The Recording Dials.
The records, which are secured by this instrument, are as follow : the total mileage ; the total number of fares (that is, the total number ot initial sixpences —or eightpences, as the case may be); the total number of further fare charges other than the initial items ; and the total number of extras. All these records, of course, are in addition to those shown on the discs, which indicate the fares and extras to the passenger on each journey.
In order to enable our readers more easily to understand the mechanism of this appliance, we have prepared a diagrammatic sketch of the arrangement of the mechanical parts of the Picard taximeter. It will be found interesting to compare this diagram with that with which we illustrated our previous article on the Aron taximeter, which appeared on the 23rd July.
Arrangement of the Mechanism.
The mechanism consists, primarily, of the three shafts, a, b, and c, which are arranged in parallel. The left spindle (c) carries the fare and" extras "indicating drums for the passenger's inspec-. tion, and also the driving gear, complete with the differential arrangement which secures the connection of the recording apparatus with either the time
clock or with the drive from the road wheel. The centre spindle (a) is the one which carries the flag, and which, by its partial rotation, allocates the registration in one or other of the manners just described. The third shaft (b) is that which carries the various totalising drums, whose indications appear through the small windows at the back of the instrument. An inspection of the diagram will readily reveal the arrangement of the principal parts. The drive from the road wheel is secured through a snail cam (f), which is attached to one of the hubs, and
which transmits the motion through a spiral gear wheel (g). The drive is then taken up to the instrument by means of a suitable flexible shaft (h), and this rotates a small-pitch worm wheel (j) through the screw (e). When the flag is in the vertical position, indicating that the vehicle is for hire, the instrument is recording nothing, as the worm wheel (j) is running free on the shaft (c).
Alternative Actuation.
The Picard taximeter, however, has a feature which is not common to all types of these appliances, in that it provides means for recording the travel of the vehicle, to which it is attached, either on a purely mileage basis, or on a basis which is a combination of time and distance, and which is usually known as the horo-kilometric system. The method of putting the recording apparatus of this taximeter into suitable gear is that of sliding laterally a small pair of ratchet wheels (i), by means oif the lever (d), which lever is operated by a side cam mounted on the shaft (a); this cam only operates when the flag is lowered. In the " For Hire " position, the small ratchet wheels are disengaged, and no motion is transmitted Lo the recording apparatus ; in the second position, which provides for records on a mileage basis solely, one of the small ratchet wheels on the sleeve is engaged with a pawl (p), which puts in train with the drive from the road wheel (which we have already described) the counters solely ; in the third position, the recording drums are actuated by whichever of the two drives—that from the ordinary clock mechanism, or that from the road drive —is travelling the faster. In the lastnamed position, the small ratchet sleeve has its two wheels in engagement with the respective pawls which transmit the drive from the alternative prime movers.
The three positions of the flag are positively located by means of a small toothed Cain, which is shown mounted on the shaft (a), and which partially locks the shaft and flag in any one of the three positions by means of a small spring-controlled lever ; a projection engages with grooves in the cam.
Operation of Totalising Drums.
Taking the totalising drums in the order in which they appear on the diagram, we see that the top or "trips made " counter is rotated through one notch on the ratchet every time the flag is pulled down, and the shaft (a) is given the corresponding. rotary motion. The second drum, which records the mileage completed by the vehicle when hired, is rotated by the pawl (in) mounted on the lever (1); this lever is pivoted on the shaft (b), and is raised and lowered by the successive actions of the pins (k) mounted on the side of the worm wheel (j). It will thus be seen that the records secured on this counter are wholly dependent on the rotation of the road wheels. The third drum is merely a fare-counter, and it acts in conjunction with whichever of the two driving gears is in operation on the shaft (c). A small device, which is really an interrupter, but which is called by the inventor an obturator, is so arranged that the third recording drum misses the first two records of each fare. This device is necessary, of course, as the initial charge is accounted for by the first or "trips made" drum. An addition of the records from the first and third drums will at any time show the total money taken for mileage. The fourth and last drum is simply a recorder for the number of extra charges secured, and the arrangement shown at the bottom of the diagram will illustrate the method of its operation. A small additional handle is provided, outside the taximeter casing, with which the driver registers by hand each additional charge, and this operation is the only one which can be controlled by the driver. The handle rotates the shaft on which it is mounted through a small angle, and so causes the pawl (r) to push forward each of the ratchet wheels one tooth. When the flag is returned to the vertical position, the shaft (a) rotates, and the small trip pin (t), by means of the lever (s), releases the drum on the shaft (c), and it is thus returned to a zero position.
All the totalising drums on the right hand of the diagram are held in position by non-return pawls, and the total dials can only be placed at zero by the release of a locking mechanism which controls these pawls.
The description of the operating mechanism of the Picard taximeter, which we have given above, refers particularly to the first examples of the smaller model constructed by M. Picard for use in England. This type is now being provided with a small additional counter, which records the total mileage travelled, in addition to the registration of the total hired mileage ; all Picard machines to be fitted to motorcahs for service in Great Britain will he found to be provided with this necessary fifth " window." A larger model is made for use on horse-drawn cabs.
The proprietors of this taximeter are specially convinced that their apparatus, besides being of a type which is approved by the Public Carriage Office authorities at Scotland Yard, and by other municipal authorities, for employment on motorcabs, will be used to a very large extent on the existing horse-drawn vehicles, whose career the stressful competition of the rapidlymultiplying rnotorcab threatens to cut short, Enquiries by those who are interested in the employment of this machine in Great Britain should be addressed to Messrs. J. J. Edwards and Company, of 28, Sackville Street, Piccadilly, W. .,.