Air Springs and Disc Brakes on New P.S.V.
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Guy Introduce Revolutionary Passenger Chassis• and Ultralightweight Eightwheeler
IN addition to representative models from the new Invincible. Mark II range of heavy-duty goods vehicles, 3uy Motors, Ltd., will be exhibiting two Anstanding new designs at Earls Court. )ne of these is the first British passenger ;hassis to have air suspension and disc Aakes as initial equipment, whilst the ather is an ultra-lightweight low-cost ight-wheeler which-is virtually an eightvheeled version of the Warrior fourvheeler.
The new passenger chassis, which is as ,et unnamed, is an underfloor-engined lesign for single-deck bus or coach bodyvork. There will be two examples at the 2ommercial Motor Show, one on the liuy stand and one in the demonstration aark. Both will be powered by Leyland ).680.150-b.h.p. oil engines, used in conunction with 'a new fully automatic (ersion of the Guy five-speed epicyclic overdrive-top) gearbox.
The passenger model bears no relationhip to previous Guy underfloor-engined lesigns, having been designed from the tart around an air-suspension layout. ndependent-front-wheel suspension has teen adopted, as it is considered that this s the easiest way to apply air springs to he front wheels, besides giving additional tdvantages in respect of roll stability and ;enerally improved suspension charactersties. A conventional rear axle is used. Firestone Airide rolling-lobe diathragrn-type air springs are employed, vith single units at each front wheel and our springs for the rear axle. The front .uspension consists of unequal-length mst wishbones at each side, the lower vishbones being longer than the upper ines. These carry the kingpins and stub txles and the upper wishbones form the ewer mountings for the air springs, vhich are on the same axis as the wishmnes.
Wide-Spring.Hase
This installation not only ensures a vide spring base to resist roll but also Oyes a ratio of spring-to-wheel frequency A 1 to L There is a levelling valve at :ach front wheel and telescopic dampers aass through the wishbones.
At the rear end, the axle is carried on teams, each of which has an air spring it each end. Torque reaction is absorbed ay two pairs of parallel locating links and here are two Panhard rods to locate the ixle laterally. A single levelling valve is neorporated in the rear-axle arrangenent. All the suspension linkages have .ubber bushes to eliminate the need for naintenance.
Girling disc brakes of the automatic elf-adjusting type, working on the iydrastatic principle are used. Single aliper units are employed on the front uses and the rear brakes are twin-caliper issemblies. They are actuated by airtydraulic means, tkieffront and rear brak trig systems being independent. A drumtype transmission hand brake is mounted at the hack of the gearbox.
The engine-gearbox unit is located midway in the chassis frame beneath the side members. The engine is a standard .Leyland unit with an 18-in.-diameter fluid coupling, but the gearbox is a new Guy development.
This is basically the five-speed epicyclic unit which Guy Motors have been manufacturing for several years, but it has been adapted for fully automatic control, using C.A.V: electrical equipment.
• An overriding control lever is mounted on the steering column and the electrical gear provides automatic selection of neutral when the vehicle is coasted to a standstill. Fourth gear is direct, whilst fifth gear is an 0.755-to-I overdrive.
The underslung-worm rear axle has a reduction ratio of 5.2 to 1. The chassis, which has a wheelbase of 18 ft., has a flat-topped frame which includes fullwidth outrigger brackets and it is suitable for 36-ft. by 8-ft. semi-integral bodywork. It is equipped with m00--20-in. tyres on B7.0 wide-base wheels.
New Eight-wheeler The new Warrior eight-wheeler has a wheelbase of 17 ft. 11 in. and will be shown with cab and platform body. Emphasis has been placed on low cost and light weight, and it is expected that a payload of at least 18 tons can be carried without exceedipg the gross legal limit of 24 tons.
Power is supplied by an A.E.C. AV 470 112 b.h.p. oil engine. This has a 14-in.diameter single-dry-plate clutch, hydraulically operated. -and is unit-mounted with a five-speed synchromesh gearbox. An Eaton two-speed rear axle affords ratios of 6.5 and 8.87 to 1, and the trailing axle of the rear bogie has coil and leaf springs
with hydraulic load compensation, these being of Primrose design.
An air-hydraulic braking system incorporates Girling two-leading-shoe units on the first, third and fourth axles. The front brakes are I5.25-in. by 4.5-in, units, whilst the rear brakes are of 15.5-in. diameter with 6-in.-wide facings; the total frictional area is 922 sq. in. Conventional semi-elliptic springs are used for both front axles and driving axle. The side members of the frame are only 9 in. deep, with 3-in. flanges.
Marles cam-and-double-roller steering is used. A 40-gal. fuel tank is fitted. The standard tyres are 9.00-20 in. and the electrical system is 24v. The forwardcontrol cab is equipped with windscreen washers, heater unit and canopy.
. Another new Guy design which will be seen at the Show is a 68-seat 30.-ft. by 8-ft.-double-deck bus based on an Arab forward-engined chassis powered by a Gardner 6LW --oil engine. This vehicle has been built to the order of Wolverhampton Transport Department; Who are taking it into service immediately after the Show, and is the first 30-footer to be employed in that city.
Automatic Gearbox
Other than the length, this .vehicle follows conventional Guy double-decker practice, but -an innovation is the use of a fully automatic _version of the .normal• Guy four-speed epicyclic gearbox. It has air-pressure cam-operated brakes and 11.00-20-in: (14-ply) front tyres and I0,00-20-in. (12-ply) rear equipment..
The body has been built by H. V. Burlingham, Ltd., and has 68 forwardfacing seats and ample baggage space. The overall unladen height is 14 ft. 7 in. The body weighs 3 tons 9 cwt.
As forecast in The Commercial Motor on August 15, the Guy exhibits at the Show will include a normal-control fourwheeler (with Rolls-Royce engine) and a forward-control eight-wheeler (Gardner 6LX) from the new Invincible range, but in addition there will be a forward-control four-wheeled tractor powered by a Meadows 6DC. 500. six-cylindered oil
engine.
This is an 8-ft. 9-in.-wheelbase model with fifth-wheel coupling and is equipped with 10.00-20-in: tyres. The five-speed constant-mesh gearbox has a direct top gear, and the 81-in.-centres worm axle has a reduction ratio of 7.25 to I. The tractor is suitable for a gross train weight of 24 tons.