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Vertical Engines are Now Fitted to All Models Built at the Paisley Works.
There has been an infusion of fresh blood into the New Arrol-Johnston Car Co., Ltd., of Underwood, Paisley, near Glasgow, and this is giving proof of its presence by developments and changes for which Mr. T. C. Pullinger is responsible. The work of re-organisation and re-generation of a large engineering works is by no means an easy task, but Mr. Pullinger certainly seems to be working along the right lines. He has neither made sweeping changes in the designs of the ArrolJohnston vehicles, nor does he intend to introduce any new types ; he has. however, given his close attention to the models which were exhibited by the company at the last commercialvehicle show at Olympia, and these have been now improved and strengthened in every detail that was likely to give rise to trouble. Beyond alterations to small details, the only important departure from previous Arrol-Johnston practice is the decision, after most careful consideration, to throw over the old horizontal engine, with its two pistons in each cylinder, and to fit to all the company's models one of the vertical type of engines which fashion has decided are the " best " for use on motor vehicles. It has often been said that " one may as well be out of the world as out of the fashion," and, attributing the halting popularity of ArrolJohnston vehicles to the whims of fashion, Mr. Pullinger has put on one side all arguments as to the relative efficiency of engines of the horizontal and vertical types, and, by the adoption of an engine with vertically-disposed cylinders for all models, has decided to " be in the swim."
A representative of the Editorial staff of this journal recently spent a day with Mr. Pullinger in the works, at Paisley, and he was then given the opportunity to examine every detail of construction in the various departments of the factory which, by the way, is well equipped with modern high-speed machinery. The " fixed plant" includes many fine examples of gear-cutting and hobbing machines, millers, and precision grinders, whilst jigs and limit gauges constitute a very important and considerable proportion of the " loose plant." The photo graphs from which the accompanying illustrations have been prepared were all taken from a two-ton chassis, but the following notes may be said also to apply to the same maker's smaller van or lorry chassis.
As may be seen from the plan view of the chassis on page 365, the engine has two cylinders, but, should any particular client insist upon the fitting of a motor belonging to the larger class, there is ample room under the bonnet for the fitting of a four-cylinder engine. A well-balanced flywheel is fitted, and this is of large diameter, and ha a cleanly-moulded and accurately-pitched vanes ; the flywheel thus acts as a fan and, as such, it " pulls "
a strong current of air through the radiator and the space under the bonnet. The core of the flywheel also acts as a casing for the Hele-Shaw clutch, and from this the power is transmitted to a four-speed-andreverse gearbox through a semi-universal joint; the details of the joint may be seen in one of the views of the gearbox. The hardened-steel blocks, which engage in the jaws on the driven member of the clutch, are carried by a star-piece. The same view also shows the double-flanged shaft, which is interposed between the star-piece and the mainshaft of the gearbox ; when this intermediate piece of shaft is removed, either the clutch or the
gearbox may be taken down, for the purpose of repair or renewal, without disturbance of any other part of the chassis, The gearbox shafts are mounted on roller bearings of the type which has been manufactured by the Arrol-Johnston company for many years. and these bearings receive a constant supply of oil, from the well of the gearbox, by capillary action through strands of wool.
The cardan-shaft joints on the older types of Arrol-Johnston chassis have been known to give trouble, on account of the difficulty attendant upon the proper lubrication of the working parts of the joint. It is true that a large aluminium cover was fitted with a view to the retention of the lubricant, but actual practice showed that the grease was thrown outwards, by the centrifugal force, on to the walls of the cover. That source of trouble has now been overcome by the fitting of a new form of cover, which closely conforms to the shape of the joint; there is now a minimum amount of clearance, and, therefore, a small quantity of
grease within the new cover will more effectively lubricate the slipper blocks and pins than did a relatively-large quantity of grease in the old " pot " form of cover. A leather gaiter closes the mouth of the aluminium casing. Two sectional views of the new joint cover are shown in the drawing of the differential-countersbaft, which we reproduce on the previous page.
An examination of this last-named drawing will also show that ball bearings have now replaced the roller bearings which previously were fitted, and the change has resulted in a reduction of the bending moments on the shafts, whilst the main-drive bevel-pinion shaft is now supported at both sides of the 16-tooth pinion—a very stiff and workmanlike form of construction, and one by which much whipping of the shaft is avoided, The differentialshaft is carried from the main mem hers of the frame by means of two east-steel brackets, which also serve as anchoring points for the back axle. These brackets have suitable housings bored in them to take the spherical ends of the differential-shaft casing ; on the old models, they were disfigured by the presence of stiffening ribs, and other projections with many corners, that might have led to fracture of the casting. The new brackets are shown. in one of the small illustrations on this page, and it may be seen that they are very stiff and clean in design.
The material and workmanship, which are put into this maker's machines, are above reproach, and the old Arrol-Johnoton dog-carts, which are to be found in many out-of-theway places throughout the kingdom, testify to the truth of this statement, as also to their reliability.
After our representative's tour of inspection through the works, the chassis which is shown on page 365 was fitted with a flat platform body, and, with nearly a full load of steel billets, the wagon was driven by Mr. E. J. C. Roberts (who has long been connected with the company's sales and demonstration branch) from the works up one of the steepest and longest hills in the vicinity of Paisley—a steady grind for a matter of 2 to 3 miles along a winding and very difficult road. The vehicle's performance was highly-creditable, and the machine's capabilities for stopping, starting, and acceleration on severe gradients were fully demonstrated, whilst the engine showed no signs of overheating.