SEDDON EXTEND IN MUL HEELER MARKET.
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MAXIMUM-CAPACITY sixand eight-wheeled chassis have been announced by Seddon Diesel Vehicles Ltd., Oldham, Lancs. These models are the first of this type to be produced by Seddon, who have hitherto concentrated on four-wheelers and passenger chassis, but their specifications suggest that they will make an immediate appeal to home and overseas operators of this class of vehicle by virtue of their simple design and choice of power units, transmissions and bogie layouts.
The Sirdar M Cummins-engined six-wheeled-40-ton-gross tractor and the Pennine Mk. 19 lightweight passenger chassis, which has an A.E.C. AH 410 horizontal oil engine, are also announced. A deseription and road-test report of the Pennine appear on pages 108-110.
Examples of these new models will be seen on the Seddon stand at Earls Court next month. A new version of the Mk. 15110 10-ton chassis, which is powered by the new Leyland 375 oil engine, and a low-loading model of the Mk. 15 7-tonner, fitted with 8.25-15-in, tyres, will also be exhibited.
Another innovation will be found on the Eagle stand. This is-a Mk. 14 tractor unit with an A.E.C. AV 470 oil engine, this unit now being-optional in all versions of the Mk. 14.
The new heavy-vehicle range comprises eight models. Three of 'these are eight-wheelers: the DD8 and the SD8 are 17-ft. 9-in.-wheelbase models; the former having a double-drive bogie, whilst the latter has a single-drive unit. The third eight-wheeler is the DD8TP, which has been designed. for tipper Use and has a wheelbase of 14 ft. 6 in. All these vehicles are rated for a gross weight of 24 tons and are suitable for trailer operation.
Three six-wheelers are also available, all with double-drive bogies. The load carriers are rated for a gross weight of 20 tons and consist of the DD6 17-ft. 9-in.-wheelbase general haulage model and The DD6TP 14-ft. 6-in.-wheelbase tipper. In addition, there is the DD6TC 11-ft. 6-in.-wheelbase tractor unit, which can be' operated at a gross train weight of 40 tons.
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The heavy-vehicle range is completed by two twin-steer six-wheelers, both of which are rated for use at 18 tons gross. These models are the TS6 general haulage chassis, which has a wheelbase of 19 ft., and the TS6TP tipper of 14-ft. wheelbase.
• The standard engine offered with these models is the new six-cylindered 150 b.h.p. Gardner 6LX, with the option of the Gardner 6L.W 112 b.h.p. unit and the Cummins HF 6 oil engine. The Cummins has a cubic capacity of 11.01 litres and outputs of 168 b.h.p. at 2,100 r.p.m. and 495 lb.-ft. at f,450 r.p.rn. With the Gardner engines a hydraulically actuated 16-in.-diameter single-dry-plate clutch is employed, and the Cummins unit has an 18-in. air-operated clutch.
David • Brown gearboxes are used with the Gardner
engines. The standard 6LX unit has the D.B. 557/480.
five-speed constant-mesh gearbox, which has forward ratios of 7.95, 4.7, 2.78, 1.56 and 1 to 1, reverse being 7.95 to I. With the 6LW engine the 557/29 gearbox is used, this being
milar to the 557/480 except for slightly different ratios. With the Cummins engine a Fuller R96 10-speed gearbox employed. The forward ratios are 9.65, 7.43, 5.8, 4.48, .54, 2.73, 2.21, 1.64, 1.27 and 1 to 1, the highand low-range verse ratios being 3.18 and 11.26 1. There is provision for fitting power take-off on either side.
In all cases the gearbox is unit-mounted with the engine, four-point layout being employed. The engine is tilted ownwards at its rear end so that the top of the bell °using lies below the normal body line, thus allowing the ody to be built to within 2 in. of the rear of the cab.
All chassis have two-piece propeller shafts with Hardy picer needle-roller-bearing universal joints. All the singlerive-bogie chassis and the Cummins and Gardner 6LXngined chassis have overhead-worm • axles with 84-4n. entres. but 71-in. centre axles are used when the 6LW
engine is.fitted. The double7drive bogies are offered Without a third :differential, with a conventional third differenz fiat, or With a new type of air-operated lockable 'third differential, -Which is engaged by a small switch on the
instrument panel. ,
A choice of ..two types of rear suspension is available. The normal road-vehicle version is a four-spring-andbalance-bearh layout,.th-e.springs being 3 in. wide and 47 in tong. For rough work a fully articulated two-spring system is offered, this having two 47-4n.-long inverted semi-elliptic
springs. . . • , Conventional beam front axles are employed, and the king-pins are carried in tapered-roller bearings. The front suspension consists of single-rate 48-in.-long springs, the leaves of which are 3 in. wide.
Air brakes are used throughout the new range, and the eight-wheelers have eight-wheel brakes as standard. Splitcircuit systems are incorporated, and in the case of the eight-wheelers the first and third axles are on one circuit and tbe second and fourth axles on the other: The dual E valve is mounted on the frame and is actuated by a conventional brake pedal.
The front and rear brakes on all models are 16-1 in. in diatneter; the front facings are 4 in. wide and the rear facings 6 in. The brakes are actuated by piston-type 'Cylinders, 5-in.-diameter assemblies being employed at the front, with 6-in.-diameter frame-mounted cylinders operating the rear brakes. A Neate multi-pull hand brake is fitted.
Marks cam-and-double-roller steering is used on all models and Vickers-Detroit hydraulic steering servos are available. A 21-in.-diameter steering wheel is fitted:
The frames of the new vehicles are built up from *-in.thick steel pressings and bolted construction is used throughout. The side members, which have 3-in, flanges, have a constant depth of 10i-in., and in -the case of the eightwheelers bracing is provided by seven deep cross-members.. A 60-gal, fuel tank is carried, on the left side of the chassis behind the batteries.
Standard tyres fitted to the new models are 9.00-20 in. (12 ply), carried on 6.00T wheels which have a 10-stud n25
mounting for +-in. B.S.F. studs. A spare wheel i5 included. Starting and lighting equipment is 24 v. The instruments include speedometer, odometer, amtineter, dual air-pressure . gauge, 'temperature gauge and the normal lighting switches. The standard chassis equipment includes the scuttle and dash assembly, cab floor, wheel-arches, front wings, heavysection front bumper and a full kit of tools.
A new design of plastics-panelled. cab is available with the range. Its upper section and. grille are similar to those of the Mk. 15 cab, although the grille is deeper. The lower panelling is somewhat different, the Skirting being flush with the upper panels and integral with the main section of the -cab. Standard fittings include a full-width wrapround two-piece Windscreen, curved rear quarter lights, fully adjustable driving seat and two-man passenger seat. Seddon-built timber or light-alloy bodywork can be supplied to -specification, painted and lettered as required. . All the new models are 8 ft wide and the eight wheeler has an Overall chassis length of 29 ft ..6 in., giving a frame length behind the cab of 24 ft. 01 in. The estimated weight of the eight-wheeled chassis and cab is 61 tons.
• Sirdar for Road Use The new Sirdar M tractor, although carrying the same type name as the heavier six-wheeled 30-ton-gross chassis road-tested earlier this year (The Commercial Motor, April 25), is much lighter and is intended solely for use as a road tractor suitable for payloads of 25-28 tons.
• As with the larger vehicle, it is a normal-control design, the cab and frontal styling being identical with those of the 30-ton-gross chassis. It has a wheelbase of 14 ft. 6 in.; overall width of 8 ft. and overall length of 22 ft. The unladen chassis and cab weight is approximately 7 tons 2 ewt.
Power is supplied by a 'Cummins HF 6 oil engine, as offered with the new sixand eight-wheelers, and an 18-in. diameter single-dry-plate air-operated clutch is fitted. A Fuller Roadranger R 96 gearbox is unit-mounted with the engine, and its ratios are the same as those of the R 96 box used in the new heavies.
Power is transmitted through a two-piece propeller shaft to the heavy-duty rear bogie. This has overhead-worm drive axles with 81--in. centres, and an air-operated lockabl third differential is standard. There is a choice of axl ratios-7.25 or 8.25 to 1.
Fully articulated suspension is em bodied. the bogie using two inverted semi-elliptic springs 54 in. long. Thes have 5-in.-wide leaves, and the layout permits a diagona
difference in the wheel level of 12 .in. Rubber-busFie torque arms are employed. The front axle is a similar um to that used on the new heavy-duty road vehicles, whilst th front springs are single-rate units, 48 in. long and 3 in wide.
Split-circuit air-pressure braking is incorporated in th Sirdar M, and 161-in.-diameter brakes. are employed at al axles. The front facings are 4 in. wide, whilst those at th rear are 6 in. wide, .giving a total frictional area of 834 sq. in. A multi-pull hand brake is used.
Robust Frame Construction
Frame side members are of similar section to those of the other new sixand eight-wheelers. Six cross-members are incorporated, and the side members are heavily flitched adjacent to the rear bogie. Fitted bolts are employed throughout the assembly, and the frame has a constant width over the side members of 3 ft. 1 in.
MarIes cam-and-double-roller steering with VickersDetroit hydraulic servo is standard. The standard tyres are 11.00-20 in. (12 ply) mounted on-7.33-20 in. wheels.
Several tyre options are available. The hubs have 10 B.S.F. studs and the spare wheel, which is standard, is mounted on a winch-type gear. The maximum recommended front-axle and rear-bogie loadings are 51 tons and 18 tons respectively.
The new forward-control. Mk. 15/10 10-ton chassis differs only from the earlier models (which remain in production) in having the new Leyland 375 oil engine. This develops 125 b.h.p. at its maximum governed speed of 2,500 r.p.m. and 109 b.h.p. at 2,200 r.p.m. as used in the Seddon. The peak torque output is 282 lb.-ft. at 1,400 r.p.m. The 375 engine is used in conjunction with the Meadows 250 C5 five-speed constant-mesh gearbox and 14-in, clutch.