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A NEW GUY
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8-TON CHASSIS
First and Full Particulars of a Robust Low-loading Chassis Incorporating a 43 h.p. Six-cylindered Engine, Four. speed Gearbox, Dropped Frame and
Pneumatic Tyre Equipment
THE past few months have been notable in the commercialvehicle world for the increase in the _number of large petrol-driven chassis that have been evolved to meet the increasing demand of operators for vehicles capable of dealing with greater loads than those for which the existing wide range of five-tonners and six-tonners is suitable. The latest addition to the ranks of what might be called "the heavies" is a Guy 8-ton chassis which, with every modern refinement and a thoroughly up-to-date specification, fully conforms to the rather specialized requirements of the large haulage contractor and the small operator who has to deal with heavy loads of relatively large bulk.
One of the outstanding features ' of this new chassis is 'unquestionably the fact that a dropped frame is used in order to make the loading height as low as possible. It is not an adaptation of the passenger chassis, however, for the new B20 vehicle has been laid out especially for use as a goods machine and in consequence every component is designed to suit the circumstances which are peculiar to the duty of a goods vehicle.
The Leading Dimensions.
Before going into details of construction it would seen] to be opportune to give a few of the main dimensions of the chassis in order that prospective purchasers may be familiar with the loading capacity, etc. With a wheelbase of 14 ft. 11 ins, and track measurements of 6 ft. 6 ins, for the front wheels, and 5 ft. 10 ins. for the rear twin wheels, the overall dimensions work out at 24 ft. 1 in. long and 7 ft. 6 ins. wide. As will be seen from the illustrations a full-width forward-control cab is used and in consequence the space allowed for pay-load is exceptionally large. From behind the cab to the centre of the rear axle measures 11 ft. 8+ ins., so that with a 7-ft. overhang (thereby conforming to the regulations in this respect) the platform can be made 18 ft. 8 ins, long and 7 ft. 6 ins. wide. With 40-in. by 8-in, pneumatic tyres the height of the top of the frame works out at 2 ft. p ins., but, of course, the platform height has to be somewhat greater, especially if it be desired to avoid wheel-arches. As a guide it may be stated that the width between the inner walls of the inside pair of tyres is 4 ft. 3+ ins., so that quite a large proportion of the platform would be unobstructed if a low loading height should be of paramount importance.
The frame itself is a sturdy structure built on normal lines with main members 12 ins, deep at the centre and 3+ ins, in the flange,
pressed out of sheet steel. There is, of course, a pronounCed arch over the rear axle, whilst the• members are splayed out at the rear to take a spare wheel find tyre. A cross-member amidships, of cruciform shape, supports a centre bearing for the propeller shaft and serves to strengthen the whole structure. Farther back a 3-in. tubular cross-member with wide flanged ends is fitted in line with the rear anchoragefor the road springs, whilst a flat pressed-steel crosspiece at the rear adds further strength.
The power unit employed is the well-known Guy six-cylindered engine, which, with bore and stroke dimensions of 4+ ins. and 5+ ins, respectively, develops 105 b.h.p. at maximum revolution speeds. It will be recalled that this unit embodies a substantial seven-bearing crankshaft and the Guy patented form of inclined-valve mechanism for which claims are made that an efficient combustion-chamber design is possible of attainment without complication. The cylinders. are cast monobloc and are rigidly bolted to an aluminium crankcase which carries the bearings for the crankshaft in webs running right across the case. Two cylinder heads with perfectly flat under surfaces are used, each covering three cylinders ; rapid decarbonization is thus facilitated because one head only need be lifted at a time and the vehicle is out of commission for the shortest possible period.
It is interesting to note how the various auxiliaries of the engine have been rendered accessible de spite the fact that a full forwardcontrol cab is used. The dynamo is installed at the front on the near side of the unit, whilst at the rear on the same side is a cradle-mounted starter motor. Above these components lie the exhaust and inlet manifolds, together with the carburetter, whilst the magneto and water pump are fitted at each end respectively of a cross-shaft at the front of the unit and are so designed that they can be changed about to suit the special requirements of forward or ordinary control.
The Clutch Details.
The dry single-plate clutch with 168 sq. ins, of friction material has an ample reserve to deal with the maximum torque of the engine. Three toggle levers give a light pedal action. The coupling from the
operating fork to the clutch pedal is rather interesting, for a hand-wheel type of master adjustment is provided on the rod running from the pedal Concerned to a swinging lever on the clutch shaft, so that as wear takes place the additional clearance can be taken up without it being necessary to reset each of the toggle arms. A short cardan shaft with fabric joints connects with the gearbox,. which has four forward speeds. Both main and lay shafts are supported at their centres, despite the fact that the shafts themselves are
of exceptionally large diameter, consequently the gears should remain quiet for a long time. A sub-frame is used for the_ suspension of the engine and gearbox, special precautions having been taken in the design of the mounting to avoid any frame distortion being transmitted to either component, engine or gearbox. An incidental advantage of this construction is that in the event of an accident when the main frame may have become dam
aged, the sub-frame carrying the engine, clutch, gearbox, universal joint, etc., can be supported by jacks and after uncoupling the attachment bolts the main frame can be lifted over these units, thereby avoiding the loss of time engendered by dismantling. The propeller shaft is in two parts, a support bearing being mounted in the frame approximately midway between the rear of the gearbox and the axle. Cross-pintype enclosed joints are used.
We now come to the steering gear. This component is the largest size of Mules gear, with cam-and-roller type of reduction, and, together
vith a 21-in.-diaineter steering vheel, it gives an exceptionally light .ction. The usual Guy feature of an Ill-loaded tubular track rod with a vick feed to the ball joints is, of !course, incorporated. The front-axle nvivel pins have renewable bushes it the bottom and tapered-roller Jearings at the top. the load on the nvivel pins themselves being taken -hrough the tapered-roller bearings. A. full-floating overhead-worm rear axle provides the final drive, with a ratio of 9i to 1. The brakes are particularly interesting, for a Dewandre servo motor is housed on each side of the frame. The servo motor on the off side of the chassis might be called a "master." Each motor applies front and rear brakes on its particular side of the vehicle. As might he expected, the whole system is coupled mechanically, so that in the event of the driver inadvertently stopping the engine or a breakage occurring in one of the suction-pipe lines the vehicle is still under control. Sepa
rate shoes in the rear drums only are operated by the hand lever.
The chassis weighs 4 tons 10 cwt. 2 qrs., the disposition of the weight being 2 tons 2 cwt. on the front wheels and 2 tons 8 cwt. 2 qrs. on the rear wheels. That it is capable of carrying the full rated capacity may be judged by the fact that the first vehicle has been subjected to prolonged tests with a gross load of nearly 10 tons ; a body allowance therefore, of nearly 2 tons is provided for,