E.R.F.
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Eight-wheeler with Automatic Gearbox and Air Springs
TODAY E.R.F.. Ltd.. announce details of a new eightwheeler goods chassis which should have an even. greater impact in the heavy-haulage field than their Rolls-Royce petrol-engined eight-wheeler when it was announced in June of last year. This time the interest is concerned not so much with the power unit as with the transmission and suspension, for the new 68GX3L lightweight chassis has a Bristol Siddeley S.R.M. fully automatic hydraulic-torque-converter gearbox, an Eaton 38D twospeed double-drive rear bogie, Hendrickson air suspension at the rear bogie also, and Girling disc brakes on the two front axles.
This new model will be exhibited on the E.R.F. stand next month, whilst there will be two similar models in the Demonstration Park which differ in that both have the rubber-sprung version of the Hendrickson suspension: one has the S.R.M. transmission and Eaton 38D axles, and the other has a constant-mesh gearbox and single-drive bogie with two-speed axle.
This new eight-wheeled type is by no means the only E.R.F. innovation this year, however. An entirely new 6 by 6 normal-control tractive unit for operation at a gross train weight of 50 tons will be exhibited at the Show, whilst examples of the new, strikingly styled LV cab, which incorporates a forward-step entrance and one-piece windscreen, will be displayed on the E.R.F., Bowyer Bros., Holmes (Preston) and Jennings stands. The three other exhibits on the E.R.F. stand consist of a 5LW-engined 14-ton-gross four-wheeler with Girling disc front brakes. a 6LX-engined 32-ton-gross tractive unit and a 6LX-engined
eight-wheeler with Bonallack Pneumajector 540-eu.-f1. tipping-tank container.
Other interesting E.R.F.s to be featured at Earls Court will include a I3-ton-gross four-wheeler with Perkins 6.354 diesel engine and insulated plastics-panelled van body on the Jennings stand, and one of the 88R petrol-engined eight-wheeled 4,000-gal. (17-ton payload) tankers on the Alf'd Miles stand.
Swedish Gearbox Design The 68GX3L eight-wheeler has a wheelbase of 16 ft. 9 in. and its unladen chassis-cab weight is 6 tons 6 cwt. The frame follows the current E.R.F. pattern, with the front bogie set back slightly and with sufficient space ahead of the leading wheels to permit the use of a forward-entry cab. The power unit is a Gardner 6LX 150-b.h.p. diesel, and this is unit mounted with the Bristol Siddeley automatic gearbox.
This box. which is made by Bristol Siddeley under licence from Svenska Rotor Maskiner A.B. (and is used in Swedish Scania-Vabis buses, for instance), incorporates a torque converter and epieyclic gearing which work together to give particularly high efficiency at low speeds, which is maintained at high-output speeds, -whilst a direct-drive lock-up clutch is incorporated so that no hydratilie losses can occur above a certain speed. The box incorporates brake bands which. provide hydraulic braking to augment the engine's braking effect.
From the torque converter, the drive passes through a twopiece propeller shaft to She Eaton 38D two-speed tandem-drive bogie. which incorporates a lockable third differential and has ratios of 4.87 and 6.77 to I. The axles are mounted on the ends of the usual Hendrickson-type walking beams, but instead of rubber "load cushions," suspension is given by two Air Ride pillow-type air springs: this air-sprung version of the Hendrickson boie has been available in the U.S.A. for a number of years, but this is the first instance of its use on a British vehicle. It weighs 2 cwt. less than the rubber-sprung bogie which, in turn, weighs 1.5 cwt. less than the E.R.E's balance-beam suspension.
Conventional semi-elliptic springs are employed at the front bogie, Steering being by Marles cam and double-roller gear, assisted by a hydraulic servo. Split-circuit air-hydraulic braking is used with two tandem master cylinders, the front brakes being Girling 16;125-in.-diameter discs and the rears Girling wedge-operated 15.5-in. by 7-in: units. With this layout there are four quite separate hydraulic circuits, giving quadruple safety. The vehicle to be exhibited has 9.00-20 (12-ply) tyres.
One of this exhibit's two sister models, which will he in the Demonstration Park, has an almost identical specification except with regard to the rear bogie. The 38D double-drive assembly is employed, but the ratios differ, whilst the suspension medium is different also, the more usual rubber cushions being incorporated. The other 68GX3L differs in respect of gearbox and rear axles. A David Brown five-speed direct-top gearbox replaces the torque-converter transmission, whilst the rear bogie is a single-drive assembly with Eaton 19800 two-speed driving axle (4.87 and 6.63 to 1).
The new 6 by 6 tractive unit, which is E.R.F.'s first normalcontrol chassis, has a wheelbase of 17 ft. 6 in and is powered by a Cummins NH220 12.17-litre six-cylinder diesel engine developing 212 b.h.p. Power is transmitted through an IS-in.diameter single-dry-plate clutch to a David Brown 561 five-speed constant-mesh gearbox with a 5.95-to-1 bottom gear and 0.701-to-1 top. The special auxiliary/transfer box is mounted amidships, and this gives ratios of 1.39 and 1 to I, with front-wheel-drive engagement by means of an air-operated multi-plate clutch working in an oil bath.
The front axle is a Kirkstall double-reduction unit and its overall ratio is 8.89 to I. Worm axles are used at the rear bogie. these having a ratio ot 8.75 to 1 and being equipped with I6.5-in. by 7-in, cam brakes. The rear-bogie suspension consists of four overslung springs, connected by balance beams, a simple layout giving adequate articulation for operation in Libya without the weight and expense of a fully articulating twospring bogie. The total brake frictional area is 956 sq. in. and the split-circuit air-pressure actuating system has diaphragmtype chambers.
A 12-in.-deep chassis frame is employed, the side members being 0.3125 in. thick, and the cross-members being bolted in position. A sub-frame over the rear bogie carries the Taskers fifth-wheel coupling.
A completely new all-steel cab has been developed for the 6x66Cu, as the new tractive unit is known. This cab has the accent on the provision of maximum ventilation and coolness in hot climates, to which end a plastics double roof is provided. Other features include reclining seats, two sleeping bunks and a 50-gal. fresh-water tank, The vehicle is fitted with Michelin 16.00-20 "Sahara X tyres and is equipped with a Darlington type 70 winch driven from the transfer-box power take-off.
The 6x66Cu has an overall length of 27 ft. 9 in, and is 8 ft. 6 in. wide. It has been designed for use with a Taskers 25-ton front-loading semi-trailer with a 36-ft. by 8-ft. 6-in. platform, and coupled to this the overall length of the complete outfit is 55 ft. 7 in.
The other vehicles on the E.R.F. stand are relatively conventional. the largest being a 68GX2 eight-wheeler with Pneumajector body. This 15-ft.-wheelbase machine is powered by a Gardner 6LX engine driving through a David Brown five-speed direct-top gearbox into the double-drive rear bogie. which has overhead-worm axles with a ratio of 5.2 to 1. Drum brakes are fitted to all four axles, with air-hydraulic actuation. and the vehicle is shod with 9.00-20 (12-ply) tyres. A Gardner 6LX engine is employed in the 64GX tractive unit also this being a 10-ft. 1-in.-wheelbase four-wheeler mounted on 10.00-20 (14-ply) tyres. The engine drives through a David Brown 10-speed gearbox into the. 7.01-to-1 double-reduction rear axle, the suspension at this axle consisting of underslung semi-elliptic springs with Aeon rubber helper springs.
Lightest of the exhibits on the E.R.F. stand is a 54G fourwheeler with Gardner 5LW diesel engine and five-speed direct-top gearbox. This vehicle has an Eaton two-speed axle and a split air,hydraulic braking system actuating front-axle disc brakes and rear-axle cam brakes. The new forward-step cab will be fitted on this exhibit, this being plastics-panelled. with some versions having light-alloy framinv and some timber framing. It has a full-width one-piece windscreen and a marked "horizontal" motif when viewed from the front, the familiar E.R.F. " egg " having been dropped. The doors contain quarter lights and wind-down windows, and the rear quarter lights are as deep as the door glazing.
Of the E.R.F. vehicles not on the E.R.F. stand, the most n26
interesting from the technical viewpoint is the Rolls-Royce-. petrol-engined eight-wheeled tanker on the Alf'd Mlles stand, full details of this machine having been published in The Commercial Motor last year. It will be exhibited with a Miles light-alloy 22-ft.-long tank and is designed to carry 17 tons of fuel oil at a maximum road speed of 52 m.p.h. There are several tankers in service in this country based on this chassis. but this will have been the first time that the design has been exhibited in public. The exhibit will have Michelin 10-22.5 tubeless "X" tyres.
Another vehicle about which little has been published but which has seen a considerable amount of service is the 64P. an example of which will be on the Jennings stand. This is a 13-ton-gross four-wheeler powered by the Perkins 6.354 directinjection diesel, the first time that engines of this make have been used by E.R.F., Ltd. As exhibited, the engine drives through a David Brown five-speed direct-top constant-mesh gearbox and Eaton two-speed axle. Drum brakes are employed On both axles and the new forward-entry cab is fitted. This vehicle has a Jennings insulated van body and another E.R.F.based van will be featured on the Jennings stand, this being an LK644 9-ton-gross vehicle with Gardner 4LK engine .and two-speed axle. An identical chassis will be alongside, but this will have a 16-ft. light-alloy brewery body.
An LV forward-entry cab will be featured on the 68GX3 eight-wheeled tipper on the Bowyer stand. this vehicle having a 6LX engine, David -Brown six-speed overdrive-top gearbox and double-drive rear bogie with lockable third differential. Two other eight-wheeled E.R.F. tippers will be sin view: one on the Edbro-B. and E. stand, with a fiLW engine, and the other on the Holmes (Preston) stand with a 6LX engine.
The remaining two E.R.F. models at the Show will he fourwheeled tractive units. The British Trailer Co. will be featuring a 54G 20-ton-gross machine powered by a 5LW engine and coupled to a 12-ton Four-in-Line semi-trailer with special aluminium-canopy-type body for the carriage of pallets. while Eagle Engineering will feature a 64GX Gardner 6LX-engined 24-ton-gross tractive unit with a 25-ton drop-frame semi-trailer.