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THE FOUR-TON CALEDON CHASSIS.

3rd February 1920
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Page 17, 3rd February 1920 — THE FOUR-TON CALEDON CHASSIS.
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Details of the Latest Model with a Single Sleeve-valve EngineDux Gearbox and F. J. Worm Gear.

ALEDON MOTORS, LTD:, have

been successful from the inauguration of the company. They have not had to pass through the trying times which' so many ther manufacturers of commercial vehicles experienced before the war, The first Caledon, machine produced in 1915 was web designed and embodied many features which had been proved successful. The manufacturers were in thee position to know what users required, as they themselves had been agents for many years before embarking on manufacture.

The latest chassis on which work is being concentrated does not differ greatly from its predecessors. It is made in two models. That intended for use as a fourton lorry is provided with a poppet-valve engine of the ordinary type; the other is a passenger model intended for char-abanes work, and this is provided with the new Caledon sleeve-valve engine, the special features of which are silence, smooth running and economy, which render it particularly suitable for this class of work.

We propose in this article to deal with the passenger model only, ai, apart from the engine, the two chassis are almost exactly similar.

The new chassis also reflects the experience which was gained whilst the manufacturers were acting as agents. Particular care has been paid, to the question of service, all the components are readily -accessible, and particular units can easily be removed from the chassis without disturbing the remainder. • The number of working parts ha.Sbeen eat dOwn considerably as compared 'with' other intakes of vehicles for similar work. The design of the engine -in 'particular cuts down the number Of ite:parts to minimum and renders its'repair 'a:mat= ter of ()Arens simplicity. 'The chassis preterits a sturdy and 7gracefill -cippeav mice which is .enlianced' the,design of the radiator, which isriotuided at the front, and has the aluminium header and bottom tanks finned, somewhat after the style of the Daimler radiator; except that the fins are not in the vertical plane

but in the horizontal. ' •

A pressed-steel frame, 8 iris. deep' at the centre and tapering to fitaiit and rear; but, otherwise straight, iS'enciPlOyed:' The dumb irons are set well Vack into the

channels and riveted into position. No sub frame is employed, as three-point suspension is used for the engine. The engine has a bore of 110 mm. and a stroke of 140 mm. ; it develops 44 b.h.p. at its normal speed of 1,500 r.p.m. It is four-cylinderecl; with tbe cylinders east in pairs, and made from the finest quality. closesgrained cast-iron. The exhaust ports are situated on the near side, and the inlet ports on the off-side. The valve port liners are made separate, accurately machined .and ground in position after assembly. The cylinder heads are detachable, and a large cover is also provided on each

cylinder so that the water jackets can be inspected and cleaned when necessary. The cylinder bores are tested to a pressure of 500 lb. per sq. in., whilst the jackets are tested to a pressure of 50 lb. per sq. in.

, The crankcase is constructed of castiron, the main bearings being supported in. the top half, whilst the bottom half acts as a sump with a capacity of three gallons: A large spherical bearing is provided it the front end, and a strong cross member is bolted to the rear, so that frame flexion cannot throw the crankshaft out of line. Two large inspection covers are provided at each side of the crankcase.

Three die-east white-metal bearings of ample dimensions are employed for the crankshaft, which is a high-tensile steel forging, machined all over and drilled for forced lubrication. The 'crankshaft is carefully balanced before assembly. High-tensile steel stampings of H-section are employed for the connecting rods, the big-end bearings of which are of die-cast white metal. The gudgeon pins are locked into the small ends, and work direct in the piston bosses.

The single sleeve-valve gear is constructed under turt-MeCtalum patents. This type of sleeve valve was Treviously known as the Argyll. In the Caledon engine a greatly 'simplified method of operating the sleeves has been introduced. It consists of a simple crank 4ncl short connecting rod to each sleeve, which give the necessary elliptical mo

tion. • The sleeve-operating shaft is casehardened, and is driven from the crankshaft by an enclosed silent chain. It-is carried on three large bearings.The valves themselves are made of cast-iron, the ports being accurately feinted on a special • machine and the sleeves being ground inside and out to -very fine limits. The pistons are also of cast-iron, each is fitted with three rings.

Lubrication is entirely automatic, and is on the -forced-feed spstem, the oil being forced under pressure to all Aha. crankshaft bearings from a plunger pump actuated hy the sleeve-operating shaft. A large oil filter is provided in the sump and a relief valve is embodied in the oil pump. An oil-level indicator is provided on the near aide of the engine.

Cooling-water circulation is by centrifugal pump, driven by a cross shaft at the front, end of the engine. A magneto of the waterproof type is driven from the front end of this cross shalt through the medium of a flexible leather coupling, Cooling is assisted by a four-bladed, pressed-steel fan driven by means of a V belt from the end of the operating, shaft, Eccentric adjustment is provided Lee the fan belt. A Claudel-Hobson oarburetter is fitted as standard.

An entirely enclosed governor, running in oil, is situated en the front end of the crankshaft, and as the connections An the carburetter are also enclosed, tampering with them is rendered a matter at diffi culty. The starting handle is carried in an extension of the crankcase, and is entirely independent of the frame, • A Ferodo-lined cone clutch_ provided -with a neat banjo-type clutch stop fitted across the frame carries the drive through the Hardy universal points, and a splhied shaft to the four Speed and reverse gear box of the special type known as the Dux, manufactured under licence from The French patentees. In this box the only sliding gear is the reverse the other gears are always in mesh, and are brought into action by means of dogs. The striking mechanism is contained in an oil-tight extension bolted to the gear

box. The change-speed lever itseliis supported by the frame, but has universal action so that no binding can occur, The gearbox is suspended from two cross members by four bolts only, and can . be removed quickly.

An unusually large oil-tight universal of the star t2,-pe,is situated behind the

gearbox, and a splined cardan shaft carries the drive to a rear universal of the sliding-block type, rendered oil-tight by a leather cover.

The rear axle is is pot-type steel east Lta ing the worm and differential being sup

ported by the cover. The worm gearing is of the David Brown F.J. tape. Steel tubes are hydraulically pressed into the

central casing, and these carry cast-steel spring brackets, which are bolted to the casing. All the wheels, which are cif the caststeel, tubular-spoked type, run on floating phosphor-bronze bushes. Those at the rear have very wide brake drains with internally-expaaling shoes. A large footbrake with externally-contracting shoes is also provided, both brakes being readily adjustable by means of snail horn adjating nuts.

The springs are long and deep; the second leaf of each is carried half round the spring eyes to give extra strength. The steering gear, which is very accessible and easily detachable, is of the -worm and segment type, the tie-bar being behind the axle.

Careful attention has been paid to the matter of lubrication: for instance, the clutch ball race has a large lubricator, and by unscrewing a plug in the rear universal this can be filled with oil.

We made inquiries as to whether the company are satisfied with the new F.J. worm gearing. They expressed complete satisfaction, and said that they no failures.

in the manufacture of

had had chassis, standardization is strictly adhered to, a.nd accuracy is .maintained by the Coleclon keeping the machine tools up to date.

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