AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

SPRINGS IN THE AIR

27th September 1957
Page 55
Page 54
Page 56
Page 57
Page 58
Page 55, 27th September 1957 — SPRINGS IN THE AIR
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

Seven Vehicle and Four Trailer Makers Show Air Suspension Systems at Frankfurt Lighter Goods Chassis Forward Control Widespread

By

John F. Moon, A.M.I.R.T.E.

AIR suspension has arrived as a welcome ionic at this year's Frankfurt International Motor Show at a time when the German transport industry is in a state of stagnation for the reasons explained on page 236.

Seven vehicle manufacturers and four trailer maker:, have air-sprung exhibits and most use German-made suspension units. The British Dunlop Pneuride system is exhibited for the first time, but is not found in any chassis, and the brake-manufacturing concerns of Westinghouse and Knorr show valve equipment for use with such systems.

Germany is ahead of Great Britain in suspension design. Admittedly, many of the layouts exhibited are prototypes, but at least the vehicles are running, which is more than can be said in Britain.

Bearing in mind that many overseas operators have for several years looked enviously at American airsprung vehicles which dollar restrictions have not allowed them to purchase, it is 'clear that if the German manufacturers can perfect their designs to meet varying export requirements, they will form an even greater danger to British overseas sales.

The other'point outstanding at the Show is the increasing number of lighter goods chassis and the preponderance of forward-control layouts. Such vehicles are, of course, the direct result of the Minister of Transport's proposed regulations. reducing weights and dimensions. There is a chance that the regulations might be favourably amended, but some manufacturers have felt it advisable to offer designs to meet the proposals, although sales resistance is strong, operators being loath to buy vehicles of a type that they do not want.

The Show, which is the 38th in the series, was opened on September, 19 by Prof. Dr. Heuss, president of the German Republie, arid it closes on Sunday. Although the total area of the grounds is slightly smaller than for the Show in 1955, the exhibition space is increased and the extension of a hall in the commercial-vehicle section has reduced the number of exterior exhibits.

Twenty-four commercial-vehicle manufacturers are exhibiting, including D.A.F. and Hogra from Holland, Beriiet from . France and Steyr-Daimler-Puch from Austria. Norwed-Bauer exhibit several Sachsenring vehicles from Zwickau, Eastern Germany..

German commercial-vehicle production has greatly increased since the time of the last Show. Whereas , during the first six months of 1955, 72,075 vehicles were produced, in the first seven months of this year 106,551 e16

units were made. Forty-eight per cent. of these products were exported, whilst the export percentage in 1955 was 42.5 per cent. Even so, Britain has, sO far this year, exported 44 per cent. more commercial vehicles than Germany.

Taking the air-sprung exhibits first, it may be recalled that at the 1955 Show the Continental tyre concern exhibited a bellows-type unit. It is this Spring which forms the backbone of most of the suspension systems to be seen this year and its application varies from maker to maker in an interesting Manner.

Henschel, for example, have used it on two vehicles. One, the HSI45TS tractor, 1.6s air suspension dt the

rear only, there being four bellows units, four levelling valves and four telescopic dampers. Where the Henschel differs from more conventional trucks, however, is that instead of heavy •radius arms to absorb torque and braking reactions and to locate the axle, two light two-leaf springs are used. This greatly simplifies the system, makes it much more compact and saves weight. This tractor is suitable for gross train weights of 25 tons.

The other Henschel exhibit with air springs is a version of the HS160LTSL underfloor-erigined bus, which has

air suspension at front and rear. The rear suspension layout is similar to that of the tractor, embodying leaf springs, but at the front, where two bellows are used, the axle is located by an A-frame which has a single-point mounting.

With both these layouts, separate air reservoirs are employed, unlike the American G.M.C. system, which utilizes the radius arms and support beams as reservoirs.

Another tractor employing air suspension is the new Krupp BUffel 24-26.1-ton unit. This vehicle, which has been built to conform with the proposed 6-b.h.p.-per-ton regula

;ion, has a 160-b.h.p. two-stroke engine. The rear axle is carried on two radius arms with a Continental bellows-type unit at the rear end of each, the layout being similar to that employed on the A.C.V. Bridgemaster bus, except for the use of air springs.

In addition to the axle location provided by the radius arms, a heavy V-frame, linked to the top of the axle, is employed, along with an anti-roll bar. In the Krupp system the two levelling valves, instead of being actuated mechanically by frame movement relative to the axle, are c18 controlled hydraulically by. an air-pressure bleed from the bellows.

M.A.N., Magirus-Deutz, Bussing and Mercedes-Benz. all show passenger vehicles with air suspension. The IVI.A.N, bus, the 7601301, is an underfloor-engined design of integral construction which is suitable for up to 125 passengers.

Air suspension units of M.A.N. design, built by Continental, are employed, but little information was forthcoming about them. They are not of the bellows type, however, and appear to work on the " rolling lobe '

system, similar to one of the American Goodyear designs. They have self-contained air cylinders, thereby dispensing with the need for separate reservoirs. The front suspension is independent and consists of unequal-length wishbones with the air units working on the tipper links. Radius arms, with the air springs behind the axle, are employed at the rear.

A M.A.N. engineer told me that there was little weight difference between the conventionally sprung and the airsprung versions of this bits, but that the latter would possibly "be 1 cwt. lighter and initially a little more expensive. Unladen, the 'completebus weighs 71 tons and has been designed for a gross weight of 16 tons.

The Magirus-Deutz Saturn II 98-passenger bus is another integral design employing air springs, and, similarly, the Bussing TU5S 90-passenger bus embodies air suspension. No details were available of the Magirus-Deutz layout, but the Bussing system has four Continental bellows units per axle, location being by means of radius arms. A similar suspension layout can be incorporated in the TU1 I bus.

Another bus employing air suspension is the Kassboltrer • Setra SPL 110-passenger model. This integral design was introduced originally in 1955 and was outstanding for its low weight of 5• tons, and for the independent suspension of all four wheels on wishbones and coil springs. Another unusual feature was the use of a Henschel 125 b.h.p. horizontal engine mounted behind the rear axle.

This design has now been modified by employing Continental air springs. The conversion was relatively simple, the coils having been replaced by Continental units.

The new Mercedes-Benz 0317 bus can be built with capacities of up to 120 passengers and was the first German bus to be offered with air suspension (The Commercial Motor, 'August •16). It has a 220-b.h.p. underfloor engine, which fact shows that Mercedes, like M.A.N., are tending to favour underfloor-eneined layouts for heavy-duty buses.

The Mercedes suspension incorporates the makers' own design of bellows units, there being two at the front axle and four at the rear. A single air reservoir is incorporated and there is one levelling valve for the front axle and two for the rear. Radius arms are used lot the axle location.

Among the trailer exhibits, four have air suspension: Bauer, D.A.F., Eytert and Schenk. Whereas all the airborne vehidies on show have bellows springs of Continental manufacture similar to the American Firestone design, all but one of the trailers have General Tire and Rubber sacktype units.

The Bauer exhibit is a tandem-axIe milk tanker semitrailer with dual tanks and plastics construction. It has two air springs and each axle is located by means of • a large frame carrying a ball joint which supports a forward extension of the main axle beam.

D.A.F., on the other hand, have developed a form of independent suspension for their tandem-axlecl semi-trailer. Each wheel is carried on a trailing arm and the layout is such as to reduce roll characteristics, at the same time providing positive wheel location. The suspension .bags are carried on longitudinal beams anchored at their outer ends to the axle carriers, and there is a single telescopic dampen on each side of the bogie. Two levelling valves are-incorporated.

The Eylert_11-12-ton single-axle semi-trailer differs from the other designs in that two Continental bellows units provide the suspension, in conjunction with radius arms and telescopic dampers.

Schenk have three trailers on show with General air springs, the most interesting being a four-wheeled passenger trailer employing short sack-type units. The axles are located by stout radius arms and there are two levelling valves per axle which provide rapid adjustment of air pressure to compensate for transverse alteration in the load position.

These short air springs are used also on a four-wheeled goods trailer with plastics body sides. The third Schenk airsprung design is a. tandem-axle semi-trailer van which has long springs similar to the Bauer layout.

Leyland-engined D.A.F. 10-tonner

There are few completely new goods vehicles at the Show, but one of the more interesting is the D.A.F. 2,0,90 D0-420, which is rated as an 8-tanner in Germany but can carry 10 tons for export purposes or, with full trailer, can run at a gross train weight of 35 tons.

A Leyland 0.680 150 b.h.p. engine powers this new D,A.F, model and a ZF six-speed gearbox is employed. This has constant-mesh engagement, but an air-assisted synchromesh unit is offered as alternative equipment. The chassis has Westinghouse braking and 11.00-20-in. (14-ply) tyres.

The cab is basically similar to previous D.A.F. models, but the front has been changed to distinguish it and the interior has been substantially modified to give greater driving comfort. The instruments are carried in a cowl directly ahead of the steering wheel, and above the windscreenthere are two lockable glove pockets.

Unlike previous D.A.F. designs, the gear lever is alongside the engine cowl, where it is appreciably easier to reach, and a ZF-Gemmer hydraulic steering servo is employed.

Henschel, bearing in mind the possible demand for lighter machines, exhibit a new forward-control 5-tanner with a horizontal underfloor engine developing 90 b.h.p: Cab-floor height is no lower than with conventional forward-engined designs, but a clear floor line has been preserved by the use of a steering-column gear change. The 50° wheel lock gives a turning circle of 39 ft.., the wheelbase being 101 ft.

Roots-type Supercharger

Another new design is the HS 120 T forward-control chassis which, in standard form, is powered by a 125 b,h.p. oil engine. This unit has, however, been fitted with a Rootstype supercharger, made by Motor•Sakosch, of Switzerland, which raises its power to 150 b,h.p. Supercharged, the HS 120 T can be operated with a trailer at a gross weight of 24 tons, and conform with the forthcoming regulation of 6 b.h.p. per ton of gross weight.

Bussing show three new goods vehicles: a 5-tot-trier and two forward-control tractors suitable for payloads of 171 and 20 tons, respectively. All these vehicles follow the conventional Bussing pattern of robust construction. The LU 7 underfloor-engined 61-tonner is to be fitted experimentally wilh Dunlop Pneuride air suspension units before the end-of the year.

Also on the Bussing stand is a 6,500 T underfloor-engined double-decker. This is not a new model, but incorporates several features to assist the conductor. The entrance to upper and lower decks is at the rear, where there is a large loading platform, and passengers pass from this to the conductor's desk on their way into the saloons. Passengers going up the rear staircase pass a photo-electric cell which actuates a counter on the conductor's desk, whilst passengers leaving the upper deck by the front staircase pass another cell which subtracts from the total recorded on the conductor's counter. Thus the conductor can tell at a glance exactly how many people are upstairs.

The same photo-electric cells close the doors automatically if the beams are not broken within 5 seconds of the last passenger leaving. A further safety device is a cell on each door which automatically opens it should there be any obstruction to prevent it closing properly. In this way, the conductor can concentrate on fare collection, which is important with a vehicle carrying 108 passengers. Mercedes-Benz have introduced a forward-control version of their L 321 chassis, which has a modern-styled cab with a c.20 deep curved one-piece windscreen. • A one-piece windscreen is a feature also of the Magirus-Deutz .Mercur 112 F 6-ton chassis. This has a steering-column gear change—a feature which is growing increasingly popular on medium-weight German vehicles.

Air-cooled Oil Engines Magirus-Deutz exhibit two new all-wheel-drive chassis, one a six-wheeler and one a four-wheeler. The six-wheeler is suitable for 15,ton dump bodies, whilst the four-wheeler has been developed for normal tippers of 6 tons capacity. Both have their military counterparts.

These Magirus-Deutz military vehicles, as with all other chassis of this make, have Deutz air-cooled engines. Faun, who also make dumpers and heavy military tractors, also use Deutz engines. Air-cooled engines are particularly suitable for these two applications, where vehicles arc working under rough conditions in all sorts of weather and are liable to be left standing in the open at night.

Among the very heavy vehicles exhibited by Faun, out standing is the K20 VA 22-ton dumper. This is a forward-control model, based on last year's K20 20-ton normal-control machine, and it is powered by a Deutz V12 air-cooled engine which develops 250 b.h.p. The dumper is 11 ft. 6. in. wide, but good driving visibility has been assured by generous glazing of the half-cab, including a large glass panel below the main windscreen to give improved forward vision.

A feature of some of these Faun dumpers is an automatic brick remover: this consists of a hinged bar, hanging downwards from each side of the body, which rests between the twin rear wheels and therefore dislodges any material which may become wedged between the tyres.

New Borgward 1f-tanners.

Borgward have introduced two new forward-control ranges, being modifications of existing 11-ton and 21-ton chassis. The 14-tanner has a set-back engine placed beneath the seats, which gives an unobstructed floor line and makes the vehicle eminently suitable for use on delivery work. These light models have independent front suspension and the engine, gearbox and front suspension units are mounted on a sub-frame which can be withdrawn simply.

The smaller range of vehicles made by Borgward under the name Goliath has been greatly modified and the vertical twin-eylindered two-stroke petrol-injection engine which, as tests by The Commercial Motor two years ago showed, is outstanding for economy, has been replaced by a new flat four-cylindered four-stroke unit. This new engine, which is . of 1.1-litre capacity, has twin carburetters and is mounted beneath the floorboards, instead of under the seat. It is used with a four-speed gearbox having steering-column control.

Krauss-Maffei, one of the few German passenger-vehicle manufacturers who are not exhibiting air-sprung vehicles, but who are known to be experimenting with them, show a new bus, the KMU 150, which follows the current trend for heavy passenger vehicles in that it has an underfloor engine, a Bussing 150 b.h.p. unit being employed. Like the lighter KMS 125 bus, it has independent front-wheel suspension and integral construction. Krauss-Maffei were among the pre-war pioneers of lightweight integral designs.

KAssbohrer, who specialize in rear-engined coaches, are exhibiting their Setra S 8 Ex. 43-Passenger coach, which is unusual in that the M.W.M. V8 air-cooled oil engine is used —the first instance of this unit applied to a coach. The M.W.M. engine has a special balanced pressure pre-combustion chamber which is claimed to give quiet running, although, being air-cooled, it is not so-quiet as the watercooled M.A.N. M-type unit.

This year's Show carries an undercurrent of slight depression in the German commercial-vehicle industry. Indeed, it is rumoured that both Henschel and Bussing have fallen upon hard times. Technical ability is high, but overall export sales are lower than our own. There is still time for British manufacturers to get ahead of the Germans, but this temporary lull should not be treated with too much confidence, particularly in view of the progress which is being made in the field of suspension.


comments powered by Disqus