THE LATEST LATIL
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high-speed 3-4-tonner
First Details of a New Archedframe Machine, Having a Powerful Engine and Doublereduction Drive
ANEW model has been added to the range of commercial chassis marketed in this country' by Latil Industrial Vehicles, Ltd., 11, Albert Embankment, London, S.E.11. The machine is intended for high-speed work, carrying a useful pay-Toad of 3-i-4 tons,
and it has an arched frame to permit a moderate floor height.
This new chassis, which is known as type SPB3, incorporates an engine of the same model as fitted in the wellknown Lath l 1B5 6-tonner. It is a fourcylindered side-valve unit, having a bore of 105 mm. and a stroke of 160 mm. The piston displacement is 5,541 c.c. and the output at 1,900 r.p.m. is 72 b.h.p. A recent improvement in this power unit consists of arranging the exhaust lead from the front end of the manifold instead of from the rear. Incidentally, the capabilities of the 6-tonner, which embodies this engine, were fully referred to in the road-test report which was published in our issue dated July lst, 1930.
The frame of the SPB3 model is upswept at a point level with the gearbox, the rise being 5; ins.; it is also arched to the extent of 8 ins, over the rear axle. The main frame members are parallel, their depth being 8 ins., and they are connected by eight channelsection cross-members. The height of the frame top amidships is only 2 ft., and the overall frame width is 2 ft. 9 ins. The cross-members are riveted to the longitudinals.
The engine, single-plate dry clutch and four-speed gearbox are mounted as a unit, the drive being taken by a short shaft, having two fabric-type universal joints to a compact box bolted 'to a cross-member, this box containing the primary reduction gear. The box has a detachable base plate and two end plates, in which a pair of herring-bone gearwheels is mounted in ball bearings, the driving pinion being above the driven pinion. The standard reduction is in the ratio of 18 to 23, although for special purposes a ratio of 17 to 24 and possibly other ratios can be provided by the maker.
Thence the drive is taken to the rear axle by another exposed shaft, also having two fabric couplings; the final drive is of the spiral-bevel type with spur differential gear, the normal ratio being 9 to 35, or nearly four to one. Such a ratio permits a small driven wheel, and the clearance under the case is 81 ins., that under the front axle being 10,1 ins.
The rear-axle case is a banjo-type welded pressing and the differential gear can be removed from the rear. The axle shafts are of the semi-floating kind, the rear wheels being mounted upon double ball bearings. The wheels are of the pressed-steel disc type, carrying 34-in. by 7-in, pneumatic tyres, dual wheels being fitted to the rear axle. The front wheels are each carried on two single ball races.
With the two standard reduction ratios given above, the four-speed gearbox, which has a central ball-type gearchange lever, gives overall ratios of 4.96, 8.89, 15.58 and 21.63 to 1 forward and 28.28 to 1 reverse. A power take-off from the gearbox can be arranged if required.
As regards the springing, the front springs are of the ordinary semi-elliptic type, shackled at their forward ends, their length being 4 ft. and their width 21 ins. Each has nine leaves. The rear springs are of the reverse-camber pattern mounted above the axle and shackled at their rear ends. They are
4 ft. 7i ins, long and 4 ins. wide, and each consists of 17 leaves.
As in the B5-type 6-tonner, a Westinghouse vacuum cylinder is employed to increase the braking efficiency. This is brought into action by the pedal and controls brakes on all four wheels. The hand lever acts through manual effort upon the rear wheels only, and there is on this new model no transmission brake.
Worm-and-sector steering gear is employed, the drop arm being outside the frame member and mounted on a splined taper shaft. The turning circle in either direction is approximately 59 ft.
As regards the dimensions of this new Latil machine, the wheelbase is 14 ft. in S. , the front track 5 ft. 5 ins, and the rear track (between the twin tyres) 5 ft. The driver is located behind the engine, yet there is a useful body-mounting space from behind the driver to the end of the frame 14 ft. 2 ins, in length, the frame overhang behind the rear-axle centre being 5 ft. 2i ins, and the overall length of the chassis 22 ft. 43r ins. The chassis weighs approximately 2 tons 14 cwt.