TWO NEW LATIL TRA
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FLIERS For Short and Long Hauls Much-improved Mark I and New Mal k Now Built at Latil's London Works. Both Dual-purpose Machines, Being Suitable for R and Cross-country Conditions FOR the transport of maximum loads, there is much to be said in favour of the type of outfit legally defined as a motor tractor and trailer. Whilst permitted a speed of 20 m.p.h., which, in this respect, places it on level terms with other comparable means, it enjoys lower taxation and its cost of operation, according to The Commercial Motor Tables of Operating Costs, is favourable.
One of the best-known British manufacturers of tractive units for trailer haulage is Latil Industrial Vehicles, Ltd., 11, Albert Embankment, London, S.E.11, the Latil Traulier having enjoyed considerable popularity in that sphere for a number of years. This company has just introduced two new models, which are now built atits London works. Their design, generally, follows. that of the prototype, but certain important modifications have been made as a result of the experience gained over the past 10 years, during which Trauliers have been in operation.
Like their predecessor, the new Trauliers are 'dualpin-pose machines., being suitable for operation on roads or soft ground. In view, however, Of the fact that cer
tam n characteristics which are highly desirable for the one purpose may constitute a limitation for the others, measures have been adopted to overcome this obvious difficulty.
Before describing these, the purposes of and differences between the two models should be outlined. The new Trauliers 'are designated Mark I and Mark II. The.
B12 former is for economic operation in a limited area where high speed is not required, some degree of traffic congestion probably obtains, and narrow streets and sharp corners have to be negotiated. It has a smaller engine than the other and is not so fast.
Mark II, whilst also well equipped for town work, is recommended for cases where long journeys will be regularly undertaken. It is more powerful and is fully capable of maintaining an average of 20 m.p.h. As mentioned before, both models are also suitable for cross-country conditions.
Readers will be aware that an outstanding feature of the Latil Traulier is the fact that it drives and steers on all four wheels. Four-wheel drive is a definite asset in many circumstances, but it has been found that for fast main-road work fOur-wheel steering (of great value at other times) is of little, if any, advantage, and may be disadvantageous.
Therefore, on the Mark II, a device has been incorporated which enables the back wheels to be locked in the parallel position and the rear steering gear to be disconnected. This is accomplished ingeniously.
The steering arrangements are straightforward. From the steering box a normal drop arm is linked to a primary lever on a longitudinal steering shaft. This, in turn, carries at each end a secondary lever coupled by pushand-pull rods to the stub-axle arms. The secondary lever at the rear actually comprises two levers. One of these is fast on the shaft and the other loose. There is a third similar lever fixed to the frame, the loose lever being between it and the other.
The push-and-pull rod (corresponding to what is more usually named the drag link) is• coupled to the loose lever, which can be moved on the shaft axially so that by cldgs, it may be engaged with either the lever keyed to the shaft or with that fixed to the frame. It is controlled by a hand lever, conveniently placed, and pro-. vision is made for positively locking it in both positions.
Other important differences between _the two models are in respect of main dimensions and frame section. The wheelbase and overall length of Mark I are 7 ft. 6 ins. and 13 ft. 6 ins, respectively, whilst the corre sponding figures for Mark II are 8 ft. 101 ins. an
14 ft. 8i ins. Their respective frame sections as approximately 4i ins. by 2f ins. by 1 in., and 411 ins by 21 ins. by A in.
There is also a small difference in gear ratio, th Mark I having a reduction in top gear of 11.46 to nd the figure for Mark II being 11.02. The difference n road speed is chiefly a question of engine r.p.m. In he Traulier for town work a unit developing 53 b.h.p. .t 2,000 r.p.m. is used, whilst the faster machine has Al engine of 75 b.h.p. governed to 2,400 r.p.m. In his connection, it should be mentioned that, as an alteriative to the latter petrol unit, the Gardner 4LK oil :ngine is available.
On both models the engines are unit mounted at three )oints on rubber. They have four cylinders and overlead valves, the stroke, in both cases, is 130 mm. and he bores of the Mark I and Mark It are 95 mm. and LOO mm. respectively. The torque developed by the ;mailer unit is 138 lb.-ft. at 1,300 r.p.m. and by the arger 180 lb.-ft. at 1,600 r.p.m.
Two ignition systems are available—coil and distriautor or Scintilla Vertex magneto. Solex governor carauretters supply the mixture.
Lubrication Systems.
On the Mark I engine an Amal pump feeds the carburetter from a 20-gallon tank, whilst on the Mark 11 an A.C.pump is used. The lubrication systems also differ. A large accessible filter, with detachable gauze, is mounted on the off side of the smaller engine and is included in the main pressure circuit. It incorporates a spring release valve so that if the element should become blocked oil will flow straight to the bearings.
On the larger unit there are two filters, mounted on the near side, which also serve as oil coolers, being generously finned. As before, they are connected in the main pressure line.
Both oil pumps are submerged and feed the main and big-end bearings, the little-ends being lubricated by splash.
Hot-spot manifolding is employed and features of the cooling systems are pump circulation, large cowled fans, and thermostat control. The Mark IT cylinder block has wet liners, but this does not apply to the smaller engine. An interesting detail is the use of Aeren encased-cable, control for the throttle.
A larger clutch than formerly is employed, the single plate being 14 ins. in diameter. In the gearbox there are two sets of wheels. The primary set gives three forward speeds and the secondary, high and low ratios. In all six, transmission is through four wheels on three shafts. There are also two reverse speeds, whilst three speeds are available to the power take-off.
Transmission Arrangements.
From the lowest gearbox shaft power is conveyed forwards and rearwards by two propeller shafts, each having two Hardy-Spicer needle-roller jOints of the latest type, to two bevel gears, incorporating differentials. Thence a Hardy-Spicer two-jointed shaft runs to each road wheel, the final drive being by spur pinion and internal gear. Each bevel gear is hung from a pair of cross-members and forms part of the sprung weight.
It is of note that the outer universals are of high-angle type, being capable of an angularity of 30 degrees on each side of the straight. The spur gears now run on tapered roller bearings, as do the wheel hubs ; formerly, ball races were used. On the Mark I, straight-toothed bevel gears are employed, whilst the larger Traulier has spiral-bevel gears.
The ratio of the final spur-gear drive is 4.93 to 1 and that of the bevel is 2.46 to 1 on the Mark I and 2.38 to 1 on the Mark II. The two secondary gearbox E14 ratios are 0.07 and 2.5 to 1, whilst the three primary ratios are 0.97, 1.76 and 3.05 to 1. .
Brakes on all four wheels are applied by the pedal oln smaller machine through Dewandre vacuum rvo gear, and on the larger by compressed-air servo paratus of the same make. They are of the contract 4 kg-band type, acting on drums outside the internal ears.
The bands are held against torque at the bottom and sire contracted at the top. It is of note that a large "lumber of stops preserves correct curvature when the band is released, and that the design gives a slight selfEnergizing effect (forwards and in reverse), but on only one half of the band. The layout comprises a single
11' ross-shaft and four cable assemblies.
A powerful and well-finned transmission brake is mounted behind the gearbox. It is intended mainly for emergencies and parking, and is operated through a pring-loaded control rod to prevent sudden application. Provision is made for direct connection to the trailer rakes, and a capacious air-storage cylinder is carried.
A pressure of 80 lb. per sq. in. is normal for laden conditions, but there is a device by which this can be reduced to 40 lb. for running light. In both the vacuum and air systems, the foot brake is direct operated if the power fails. A vacuum tank can also be supplied.
A feature of the suspension system is the use of long springs, the forward ends of which work in guides instead of being shackled. This arrangement permits a degree of twist and thus allows free movement of the axles when irregular ground is being traversed.
These Trauliers are equipped to carry a superimposed load of 25-30 cwt. The main object of this is for the sake of tyre adhesion. The wheels of the Mark I are shod with 32 by 6 tyre,s, whilst those of the Mark Ii have 9 by 22 equipment.
Despite the many improvements that have been effected in designing these two Laths, it is especially noteworthy that an important reduction, amounting to about -£150 (it formerly cost £750) has been made in the price of the Mark I, which replaces the earlier machine of the same designation. Moreover, model Mark II, which can be described as an innovation, because it does not replace a former type, but, as it were, opens up new ground, is offered at an attractive figure comparable in respect of value for money with its smaller confrere.