:lass I — The "Combined Unit" Type.
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The principle of combining the main eatures of these light chassis into a Ingle rigid unit has found favour with . considerable number of prominent nanufacturers. The effect of this type ■ f construction on the general appearince of the .machine is to render it unleniably attractive. It gives an impresion to the casual observer of extreme implieity, rigidity, and strength, corn'bled with lightness of structure. That here are limitations to this class of lesign it would be idle to deny. Unless .Treat care is taken in the drawing )ffice, and the general arrangement is 'cry skilfully thought out, the advan:ages mentioned above may be outveighed by the disadvantage of inaccesdbility.
The main feature of this method of :onstruction is the combination, in one igid casting, of the casings of two or nore of the chief mechanical units of he chassis. The engine and gearbox :asings, as a rule, in this class, are :ast in one piece, with an intermediate .7overing for the clutch between the :wo. The avowed objects of the makers xre : to secure a simple and rigid form )f. construction ; to enable the principal 3ortion of the mechanism, in case of 'allure, to be removed en blot with 2ase ; and to dispense with the necessity or accurate lining up between the
main details when erecting or replacing.
Our diagrammatic sketch clearly indicates the general principles on which this type of machine is constructed. The engine (A) is carried in front of the dash, in the usual position, and can, of course, have either two or four cylinders. The crank-chamber casting is extended, round the flywheel and clutch, to the gearboxtase, of which it forms an integral part. It merely remains, therefore, to connect this selfcontained unit through an articulated drive to the live rear axle. This engine-gearbox combination simplifies the frame construction.
Argyll.
A notable example in Class I is the latest cab chassis manufactured by Arg-ylls, Ltd., of Xexarldria, N.B. The address of the Loneliin Company is 17, Newman Street, W. We gave such a full description of this machine last week, that it is unnecessary for us to do more than draw attention to its principal features. It corresponds very accurately to the description of the class characteristics given above. Engine, gearbox, clutch, flywheel, countershaft brake, and change-speed gear are all built upon the one casting. All four cylinders are cast in one piece, with a
boldly-designed water-outlet pipe screwed to the top of the water jacket. The crankshaft is carried in ball bearings, and, amongst other noticeable features, is the design of the back axle, which enables the differential to be dissembled with the maximum of ease.
Fiat.
The cab chassis marketed by Fiat Motors, Ltd., of 37-38, Long Acre, W,C., is a remarkable little machineLike the Argyll, in general principles it follows the broad lines of classification we have stated for this type. As an example of clever casting, the prospective buyer will have to travel far to discover anything to beat the combined four-cylinders and top half of the crank case, which is a remarkable feature. This, so far, is the last word in the school of " combined unit " construction, but we are forced to confess we are unable to discover any special reason for the accomplishment of such a feat in foundry work. Again, the lower half of the crank chamber is part and parcel of the aluminium gearbox casing, which it reaches by surrounding the flywheel. The backaxle casing has a tubular extension which, while acting as a torque bar and radius rod carries the propeller shaft.
Thames.
The cab chassis which is produced at the shops of the Thames Iron Works, Shipbuilding and Engineering Co., Ltd., whose London address is 17, Philpot Lane, E.C., follows the general lines of Class I. It has a two-cylinder engine, with a bore of 4 inches and a.
piston stroke of inches. A noticeable feature, and one in which this machine is unique in its class, is its worm-driven back axle.
Rover.
As might he anticipated, the Rover car is of unusual design throughout. The London offices of the Company, whose works are at Coventry, are situated at 59-61, New Oxford Street, W. The two-cylinder engine, the gearbox and clutch are all combined as one unit, and the bevel-driven, live back axle has its propeller shaft carried in a tubular extension to the axle casing.
Mass.
Another example of the combined . unit deSigr is•the Ma is car, handled by the Lancaster 3,L .for Garage, W.