Seals and Sealing.
Page 17
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In the current schedule of regulations for the construction and use of taximeters in the Metropolis, several sections are included which deal with the effective sealing of important adjustable portions of the apparatus. We dealt with these regulations, as a whole, in our issue of the 1st instant, and in the Editorial columns two weeks ago we had occasion to state that the Public Carriage Office Authorities at Scotland Yard were interpreting these and other regulations of a similar nature in a reasonable and broad-minded manner. Very considerable inconvenience, in addition to actual financial loss, was likely to have been incurred had those stipulations been strictly enforced by which it was rendered improper to run a motorcab, under any circumstances, unless all the seals were intact. In the event of accidental damage or deliberate removal of any of the official seals, the vehicle need not cease running until such seals can be replaced. The first available opportunity suffices for resealing, owing to the reasonable official interpretation of which we have written, and which has been the practice all this month.
As a matter of fact, we have heard it said that all this "pother " about seals and sealing of the taximeter mechanism of London motoreahs is of little practical utility. There are few drivers of locomotives who could not, on occasion, release a safety valve which normally was supposed to be padlocked or otherwise sealed. Were it worth the taxicabby's while, we think his ingenuity would not be far inferior to that of the loco. driver, and, therefore, if any preventive be employed in this ease, it must be of an inviolable kind. If a taximeter could easily be "faked," so far as its internal mechanism were concerned, we are convinced that it would be only human for certain drivers promptly to attempt to "fake " them. Such " doctoring," however, would be a matter of extreme delicacy, and would involve, moreover, very considerable, specialised, mechanical ability.
Seals on the Instrument.
The seals on the instrument itself—two in number are, therefore, only useful in the main as a check by the National Physical Laboratory—which certifies the taximeters' bills of health from time to time—upon the manufacturers. The authorities are assured, in this way, that such mechanism as they have calibrated shall, in default of accidental mechanical derangement, be free from miauthorised readjustment on the part of the makers. As the seals on the fare-registering apparatus itself actually, therefore, serve a definite purpose, they should be beyond suspicion. Alternative methods are offered by the authorities. Makers may either have a wired-on or an inset seal. In the latter case, the latest regulations specify that the holes for the reception of the lead must be deeply undercut, and must not he of less diameter than fiveeighths of an inch (16 millimetres). The wired-on seals, which are alternatively provided by the National Physical Laboratory, are of the usual hollow pattern, and are of lead. Removal of one of these seals, after it has once been effectively stamped, is almost a matter of impossibility, owing to the use of special wire; this consists of a single straight wire, round which a lighter strand is wound. The lead is forced into the spaces between the spiral windings thus formed.
Seals on the Driving Mechanism.
This last set of taximeter regulations initiates the practice of sealing the driving and transmission details, and such sealing may be carried out at any " passing " station. As a rule, live seals are affixed—in this case, by the Carriage Office inspectors. Some stations, however, we learn, are satisfied with four or even three separate fastenings. In the case of the largest number, two are wired on to the bracket which carries the taximeter, two more are used to protect the star-wheel bracket, and the last may be used at discretion to identify the flexible shaft and its tube or some other detail. The utility of this last series of seals seems doubtful, and certainly the method of carrying out the new regulation is open to criticism. All the seals on the driving mechanism are wired on, but it is notorious that such attachments are very liable to chafe and vibrate, whilst, in very many cases, they soon drop off. The police authorities use a plain wire, which is quite easily drawn through the seal, and as easily replaced, if need be. If it be conceded that it is necessary to guard against unauthorised tampering with the driving meelianism, the sealing should be of such a nature that tampering would become a mechanical impossibility, in order to ensure the confidence of both parties to the contract. If an ordinary lead seal and plain wire be adopted, the wire should be ingeniously crossed and twisted through the seal before clamping. If no alternative can be found to the wired-on seal, means should be taken to ensure that the seal will not chafe through its pendant wire. We would recommend that similar wire to that used by the National Physical Laboratory should be adopted for the use of the Scotland Yard inspectors. In most cases, where loose seals are now being fixed to the driving-gear details, the wire is passed through the ends of the fixing 'bolts. These bolts might equally well be riveted over, and then stamped with a metal stamp.
In conclusion, we would draw the attention of the autinrities to the fact that a number of ingenious patented devices for sealing purposes is on the market. Many of thesa are stamped from sheet metal with serrated edges, which edges are adapted to interlock when they are bent over. The best thing of its sort, however, appears to us to be an American device known as the Murray. This we illustrate, and the drawing is self-explanatory. It will be noticed that no clamping or sealing is necessary, and that entire mutilation can alone effect its removal.