THE 30-CWT. JACKSON HOLROYD.
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A New Chassis with a Double Reduction Rear Axle of the Live Type.
PA RT1CULA.RS of the new Jackson Holroyd chassis have been awaited with considerable interest, as it is the result of exhaustive testa extending over a period of several years. • The manufacturers are James Whiteley, Ltd., Eagle Workie Well Lane, Halifax. They are.of the opinion that it is a great mistake to place a new chassis on themarket until the makers are thoroughly convinced that it is of good design, reliable, and free from excessive wear. They could have brought this chassis to the public notice •
some considerable timebut they preferred to "keep it dark' until they were themselves satisfied.
The frame consists of two rolled channel steel side members,' 4f ins. by 2 ins., inswept about ins, close to the !rear hangers of the front springs. Five ■ erose members are provided, three of them being of channel seetion and the other two tubular, The epring hangers are substantial, and made of cast-steel alloy.. The dumb-irons are bolted to the bottorn-flangs of the side members, and are carried back some distance along these flanges. The frame is perfectly straight throughout in the horizontal plane. The engine is four-cylindered with the cylinders cast in pairs, the bore and stroke being 4. ins. and 5 ins. respectively. All the valves are on the near side, and are enclosed by easily-detachable covers.
The crankcase has two large inspection covers, on one of which is cast the large oil filler, whilst the other carries an oil pump of the plunger and spring type, the plunger being worked by a cam from the camshaft.
Water circulation is by centrifugal pump, the pump being driven through a small universal joint of the jaw and pin type. The overhead water leads are of large diameter, and should assist the circulation to a great extent. A Zenith carburetter is fitted at the near side Of the engine, whilst the magneto is situated at the off-side.
The starting hand& and fan are carried on a main frame cross member.
Three speeds forward and a reverse are provided by the gearbox. Both the engine and eearbox are carried on a subframe, which is slung to the main frame by long 'Allis. The gearbox has four holding-down brackets, as also has the engine. Incidentally, the crankcase is of continuous web construction which stiffens it and prevents any risk of warping under stress. The clutch is of the internal cone type, the cone being of aluminium lined with leather.
Both brakes ate of the internalexpanding type. The foot brake operates on a drum behind the gearbox, whilst the hand brake operates on drums 'bolted to the rear wheels, which, incidentally, are of the wood artillery type: .
The back axle is of the double-reduction type, the first reduction being by spur gears. The final drive is througn bevels. The main axle casing is divided vertically into two halves, and fitted with cast-steel extension pieces, which carry the spring brackets. The axle is of the live type. The driving shafts., which are supported in than bearings, carry the load and also transmit the power. The torque member consists of two tubes, fixed to the top and bottom of the axle casing and slung at the frOnt end front a cross member.:
The drive from the gearbox is through an open cardan shaft fitted with two block-type universal joints, both of which can slide. — Steering is by worm and complete wheel, the worm being solid with the steering shaft.