DRIVING AND BRAKING ON ALL WHEELS.
Page 11
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A Detailed Description of an interesting Form of Tractor for Tractor-trailer Combinations.
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A NEW tractor for tractor-trailer • combinations, for which the makers think there will be a considerable de. mand on this side of the Atlantic, has beei designed and produced by the Walter Motor Truck Co., of 227-243, West 61st Street, New York. In order to develop this demand they are now establishing agencies in various countries, and it is most probable that this
• country will Come within the scope of their activities.
The Walter tractor hasi a short wheelbase, and its small turning radius and rug-ged construction particularly . adapt it for hauling a semi-trailer of 15 tons capacity. The design is a development of the same eorns pany's tractor snow-plough, which met with considerable success in dealing with the severe American snows last. winter.
The suspended drive, a patented feature of Waiter products, has been retained in this model. Instead of being mounted on the axle, as is the conventional practice, the differentials:and their .housings are suspended from the fraine, short, transverse cardan shafts transmitting the drive -to the four internal gear driven wheels. Considerably heavier rear axle construction allows fen-the support thereby of, approximately, 40 per cent, of the Weight of the loaded semi
trailer. . •
•• A Waukesha engine is employed, this, having four cylin
ders of Lore and stroke, and being governed • •down to 1;200 r.p.m. The gearbox gives five forward speeds and a reverse. Because of the fact that the clutch shaft is rather longer than in usual types, it has been possible to arrange the differential compartment for the forward axle between the flywheel and gear box as an integral part of the transmission case. . The forward differential is driven by a bevel pinion at the front end of the transmission shaft, whilst that at the rear is driven through an enclosed propeller shaft carrying a duplicate bevel pinion and fabric coupling at the rear end of the transmission shaft.
Employment -of Self-locking Differentials.
A differential, contained in the coon-, tershaft assembly, equalizes the drive between the front and rear axles -while turning, the steering being effected only by the front wheels.. Every differential is of the Walter self-locking type, whilst the rear differential housing is carried on the frame of -the tractor. The front wheels have a steering lock of 35 degrees. The'final drive of all four wheels is of the internal-gear type.
Of the six brakes provided, four are
carried at the outer ends of the transverse differential equalizing gearshafts, whilst the remaining two bear. on the miter surfaces of the rear-wheel internalgear housings. The first group is connected • to the pedal, each brake being of 10 ins; diameter and 5 ins. face. The rear-wheel brakes are worked by a hand lever, and have a 21-in, diameter and 21-in. face.
The forward transverse differential
lying between the gearbox and the clutch, the engine is disposed ahead of the front axle, and is thus very accessible for all adjustments. Moreover, the overhanging weight tends to equalize tie load when the Semi-trailer is attached, whilst, as the pivotal centre of the trailer is placed 6 ins, ahead of the centre of the. rear axle, a portion of its weight • is Lorne by the front wheels. The makers declare that the placing of the engine and the cab so far forward results in easy riding, the front springs being designed to carry a load which does not vary to a great extent.
The wheelbase is 8 ft. 4 ins., and the track, both front and rear, 5 ft. 8 ins. The eaststeel wheels are shod with 441in. by 7-in. solids, dual' tyrea being fitted at the rear. Long, heavy gussets at the ends of the cross-members liberally reinforce the frame, the side and end channels being . made of -I-in. pressed steel, 8 ins, deep with 3-in. flanges.
The total weight., without the pivot Support, is 9,100 lb. Half-doors, ventilating windscreen, and curtains are fitted to the cab, 'wherein a 20-in. driving wheel and convenient controls make for easy operation. Set in the dash alongside the hood are 8-in, electric headlamps.
The five-speed • transmission
gives a wide range of speed and drawbar pull. The maximum total gear ratio is 85 to 1, the minimum 8.5 to 1. Thus, at 1,200 r.p.m., the relative drawbar pulls are 10,000 lb. and 1,000 lb. respectively. The maximum governed -speed is 16 m.p.h., whilst the minimum turning radius over the out side of the chassis is Ili ft..