PHASES OF PASSENGER TRAVEL
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Notes on Every Aspect of Coach and Bus Development.
ANEW method of body construction which has come to our notice recently, and which is the invention of Mr, Leon Barradell, AlA., of Burham, Rochester, is interesting, because its employment should provide a useful contribution to present systems of metal-framework construction, at the same time resulting in a considerable saving in weight when compared with
the wood-frame method. Mr. Bar radell's system, which is protected by patents, snakes use of metal framemembers of a reinforced channel section in conjunction with light wood fillets. The fillets are slipped into flanges on both sides of the channel-sectioned members, and the panelling, whether it be of metal, plywood or other material, is held to the wood fillets by ordinary wood screws, elongated holes or slots being provided in the flanges of the metal frame-members through which the screws pass.
The construction is, therefore, strictly speaking, a composite one, in which metal and wood are utilized, but the stresses are borne by the metal members, and so little timber is used that for all practical purposes the construction may be described as being of the all-metal type.
From the point of view of lightness in weight and bearing in mind the narrow sections of the frame-members used, the new system would appear to have practically all the advantages of all-metal construction, whilst, at the same time, certain of the shortcomings of this system are overcome.
The inventor claims that the use of his patented method redu,les the cost of manufacture and of repair. All members can be marked off on the bench, no drilling or• riVeting being
done ir situ. The body is easy to construct and does not demand the employment of special craftsmen. Purchasers' individual requirements of shape and design are easily catered for. The inventor also claims that sufficient flexibility is provided by his system to allow for normal chassis torsion, and that a reduction in height can be made on account of the small section that is, possible for cross-bearers and roofsticks.
Other advantages may be noted. By reason of the elongated holes, the drilling of panels when in position is largely avoided. The slots are of a specific length and a regular distance apart, so that, having located the position in a panel for the end screw-hole, the workman can safely drill all the other holes along the panel edge with the assurance that the latitude allowed him by the length of the slots will be quite sufficient to accommodate a slight error in the location of the panel when he comes to fit it. This may appear a small point, but, actually, it means an important saving of time and labour.
Another advantage is that should a frame-member prove to be a fraction of an inch too long or too short, the dis
crepaney may be allowed for by the use of a distance-piece or by slightly reducing the section of the wooden fillet in the member to whish it is to be joined, so that precise alignment is obtainable without the necessity of producing frame-members of very exact length.
The channel-sectioned members may be used for all the purposes for which the orthodox coachbuilder employs beams of ash or other timbers. Crossbearers, pillars, uprights, waist-rails, cant-rails, seat-rails and roof-sticks may all be made with the standard type of channel-sectioned metal member, and only a few different sizes of this material need be kept in stock. For floor-bearers and similar components which have to be exceedingly strong, it is quite a simple matter to employ two lengths of the standard metal framing, these being held together by bolts and distance-pieces, and forming a beam which gives considerable rigidity, although it is of conveniently small depth.
Cross-joints are effected with boxtype pressed-metal knee-pieces, bolts and nuts—a means which renders the replacement of a damaged member a simple task. Mouldings are fitted by screwing into the wood fillets through the slots already referred to.
The method of construction would appear to have distinct possibilities, the most important feature being the saving ill weight which it permits. In this respect, the patentee claims that by the adoption of his system and the employment of aluminium panels and rooting, duralumin main members and Plymax flooring, it is possible to
construct a single-deck bus body having a weight which is about two-thirds of the weight of it similar body built up in the orthodox manner with ash members, light-steel panelling and wood flooring and roof. The invention is one which appears to warrant attention.