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a British premium tractive unit
Page 96
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By D. Lloyd, BSc
Part 5: the cab and its equipment
THE part of a lorry which is most important from the driver's point of view is the cab and it is in standards of cab comfort that British lorries fall furthest behind their Continental equivalents. This is particularly so in the case of heavy lorries, the vehicles used primarily for long-distance work where a comfortable cab is more important than on short runs.
Although some heavy vehicle cabs, either recently introduced or still in the development stage, are a considerable improvement on previous models, the majority of British heavy vehicle cabs are masterpieces of bad design. An excessive noise level is probably the worst feature, while a complete issue of CM could be filled with examples of badly placed controls. Among the most common are handbrake and /or gearchange levers so placed that the unwary driver grazes his knuckles or traps his fingers when using them, accelerator linkage so stiff that the right leg aches with the effort of holding the throttle open, windscreen wipers that don't clear the part of the screen in front of the driver's eyes, large holes in the floor around foot controls and steering column, mirrors hidden by windscreen or door pillars, windows that jam open or shut and so on. One well-known model of not many years ago had a gear lever directly between the clutch pedal and driver's seat — a prize example. The lack of a suitable heater and no proper ventilation make these cabs like refrigerators in winter and ovens in summer, while having the engine in the cab between the seats means that the only space for carrying tools, spares and luggage is the foot-well in front of the left-hand seat.
The cabs of most medium and small lorries are much better and, apart from cost there is no reason why the cab of a heavy lorry, in particular a 32-ton-gcw tractive unit, should be any worse than that of a smaller lorry, and since a premium specification tractor is built up to a standard, not down to a price, a luxury cab better than the cabs on the leading Continental makes is required.
Ideally this should be a completely new cab designed specifically for a premium specification vehicle, but economics demand that it be based on an existing cab, and the Motor Panels Transcontinental cab comes nearest to meeting the requirements. This is the second full-width all-steel cab available to independent manufacturers, and replaces Motor Panels' first full-width cab, as used on the ERF 64 CU 335 which was a widened version of the earlier 2.3-metre cab. The Transcontinental consists of seven main units which can be assembled to give several variations on the basic cab, so it is available as a sleeper, non-sleeper or crew cab, fixed or tilt, right-hand or left-hand drive, and the floor structure can be tailored to suit most axle, chassis and engine positions. Different front panel assemblies, interior trim, instruments and fittings can be supplied to suit different heavy-vehiele manufacturers, so incorporating the instrument layout, seats, mirrors and most features suggested for a premium specification cab in the Transcontinental should be no problem. What follows is a list of these features and the reasons for them.
Safety cab
The cab should be strong enough to meet the Swedish safety cab regulations, the justification for a safety cab being dramatically demonstrated during the CM Road Test of a Scania 80 tractor. Overall shape should avoid unnecessary projections and sharp corners to keep wind noise to a minimum, and the windscreen should slope back. In an aerodynamically inefficient cab wind noise can be high and is more noticeable if the cab is well insulated from engine noise. The cab should tilt, using a hydraulic ram, as on Scania cabs, for access to the engine, but dipstick and oil filter should be accessible from the catwalk behind the cab. Water filler could also be here or at the front depending on the position of the radiator header tank. Headroom must be adequate for a tall driver and overall cab width should be 2.45m — the same as an ISO container.
It is important that the cab has a flat floor or only a low engine hump to the front of the seats, so that the driver can step across to the other side of the cab if necessary and a three-man passenger seat can be fitted. The third seat would be on top of the engine, so could be an occasional seat. Most heavy vehicles with large in-line six-cylinder engines have two seats with a large engine hump between them occupying the centre of the cab. This is the result of the cab being built as low as possible, and there being a large fixed fan in front of the top of the engine. On a unit intended for long-distance work a high cab is at little disadvantage as it will probably be pulling a high trailer, and the driver is not climbing in and out very often. Visibility from a high cab is better so on the premium specification tractive unit the floor is high enough to cover the wheel arches, and the top of the engine will be below seat height. Since a very large radiator and a thermostat-controlled fan are to be used, the fan does not have to be in front of the top of the engine. It could be lower, driven from the crankshaft via a viscous coupling, or two fans one on either side of the engine could be used, so the engine hump in front of the seats is much reduced or eliminated.
For maximum visibility a one-piece windscreen should be fitted, of laminated glass to comply with German vehicle technical control regulations. The top of the windscreen should be well above the driver's eye level for good upward visibility. For proper rearward vision, Spafax flat mirrors with spring loaded mountings would be used on both sides mounted on Bedford folding arms. On the left (assuming right-hand drive) would also be a Volvo convex mirror to keep the back of the trailer in view and, if the air flow round the cab made them necessary, mudshields for the mirrors 1)vould be fitted. A minor but important point is that the right-hand mirror would be fitted below the driver's eye level so that it did not form a blind spot. There should be a luggage shelf behind the passenger seats with the space underneath it on the left of the engine, forming a cupboard for stowing the tools and spares and a supply of food and drink, if desired, on a long Continental
run. The shelf and cupboard should be narrow to keep the front-tb-back measurement of the cab down. About 30 cm internal width for the cupboard is enough. Behind the driver's seat would be a space to about seat level for hanging coats, and on the floor could be a small refrigerator. Heatwaves would be no problem with a supply of ice-cold drinks: Also for hot weather would be an openable roof light, and the heater blowers could be used to blow cool air.
For cold weather, an efficient heater/demister which warms all the cab, and can keep the driver's right foot warm, is essential, and the conventional hot-water heater has a number of disadvantages. When parked it is necessary to keep the engine ticking over (illegal in Germany) and when running light it takes a long time to warm up on a really cold morning when the defroster is most necessary, so a diesel fuel fired heater, as fitted to IMagirus Deutz vehicles, would be used. The heater should be powerful enough to maintain 20°C inside the cab when it is —1CPC outside, for UK use, and 20°C inside when it is —30C outside, for Central Europe. Through-flow ventilation, with the driver's input in line with the steering column would be fitted. It should not be necessary to mention the position of the driver's input, but it is
amazing that on all cars to which this ventilation system is fitted, it is located where it freezes his right hand if he holds the steering wheel in the conventional quarter to three position.
The right-hand window would have a single-stroke Leyland winder, but the left-hand window would have an electric winder, so that it could be lowered and raised on the move. There would be a kerb window in the left-hand door or, alternatively, the Italian system of a downward facing mirror. It is sometimes an advantage to be able to lock the cab doors from the inside so Wilmot Breedon locks of the type used on the 1.5-litre (later 1.6 litre) BMC Farina cars would be fitted.
A fully sprung driver's seat such as the Bostrom Viking or Chapman Superide could be used but upholstered in real leather to lengthen the life. A possible alternative is the recently announced Dunlop air suspension seat.
On the control layout illustrated, the brake to the left of the driver's seat, behind the gear lever, could be the Telma control, in which case the trailer brake is mounted on the right of the instrument panel, or the positions of these brake controls could be reversed. The foot control pedals are hinged at the bottom for correct ankle action, but the clutch and accelerator have hydraulic actuation, and the service brake valve is in a closed compartment under the cab floor so the only opening right through the cab floor is for the gear lever, as the remote control remains attached to the engine when the cab is tilted.
Instrument layout is the one described in the Smiths ergonomic approach to heavy commercial vehicle instrumentation. Although this comprehensive report on ergonomically designed instrumentation was published in April 1971 it is an indication of the extremely conservative outlook of the British commercial vehicle industry that it has been ignored. The layout has three panels, the central one carrying only data essential to the driver while in motion, the second panel carrying gauges which can be read at convenient intervals, while the third is for switches and heater controls. The switch panel has a stepped lip so that fog light, windscreen wiper and washer switches are not confused in the dark, and to its left in the premium specification unit would be lockable glove compartments with the lids forming tables when open. Instruments on the central panel include the tachograph but the model shown in the photograph is not the Gitac which Smiths make under licence.
The three air brake gauges, rev counter and oil temperature gauge are also on the central panel. Oil temperature is more important than oil pressure or water temperature as it indicates if the engine is overheating through being overworked, so the oil pressure and water temperature gauges are on the secondary panel along with the axle load indicator (no excuse for overloading!) fuel gauge and voltmeter. Smiths say it is not practicable to devise a fuel gauge to read accurately in litres or gallons so the driver must still dip the tanks with a metre rule when entering or leaving Germany to avoid trouble with Treibstaffausweises/Namlichkeitsnachweises (i.e. diesel tax) and a voltmeter is preferred to an ammeter as the latter would not indicate trouble if the alternator was still charging a flat battery. There is space on the second panel for two extra gauges and for these I would choose an outside temperature gauge so the driver would know if it was freezing outside and ice patches were forming, or what degree of cold start is required on a very cold morning; and, for use in some areas overseas where signposting is poor, a compass. Possible future developments include a reliable sump oil level gauge and tyre pressure gauge. All gauges are arranged so that the pointers are vertical when readings are normal and danger sectors are coloured red. The layout also includes an elaborate warning light system with a master warning light marked "STOP" coming on in the event of sudden failure of any vehicle system.
The radio, under the second panel, is no longer regarded as a luxury item. Apart from BBC reports on road conditions a radio combats motorway boredom leading to drowsiness, which is a major factor in motorway crashes. Smiths Industries point out that some of the 60mm diameter instruments are not yet available in the form described, but their rationalized commercial vehicle instrument range of 52mm diameter instruments can be used in the ergonomically designed layout. The premium specification tractive unit layout would differ from the illustration because a brake control, already mentioned, would be on the right of the instrument panel and a Ford combined lights/indicator control on the steering column. On the lights switch "dip" is used as the "dim" position. The driver's air inlet would be above the middle of the central panel.
For overseas use there is some advantage in left-hand drive as it makes overtaking on single-carriageway roads easier, but against this is the fact that with right-hand drive it is easier to see where the back of the trailer is on tight right turns in narrow streets, and in some traffic conditions it is safer to enter or leave the cab on the pavement side. Also an international operator doing a large non-motorway mileage in Britain would prefer right-hand drive as left-hand drive is a considerable handicap on congested British main roads, so our premium specification unit should be right-hand drive.
The importance of a low noise level in the cab does not need explaining and, apart from the silencing measures mentioned in the section on engines, there would be a thick layer of acoustic cladding under all the cab and at the back near the exhaust. The cab mounting points would be rubber insulated. Total interior noise is road noise (which is outside the vehicle designer's control) plus engine noise plus wind noise and this should not be more than 80 decibels (A) at 60 mph air speed. This figure should be compared with a maximum noise level of 78 dBA in a Scania LB140 cab in laboratory tests, and figures in the 85 to 90 dBA range in the sort of cab mentioned in the first paragraph of this article. It should be remembered that the decibel scale is logarithmic, so an increment of 10 dBA doubles the noise level, and continuous exposure to noise levels above 85 dBA can cause permanent damage to the ears.
The interior of the cab should be finished to a high standard, with sun visors, seat belt fixing points, padded trim, rubber mats and so on.
Sleeper cabs No provision is made for a sleeper cab. The practice of drivers sleeping overnight in lorry cabs is to be deplored and it is hoped that trade union opposition to it will remain strong, in spite of Britain having to conform to EEC transport regulations. British TIR operators using sleeper cabs argue that they save the driver having to find and pay for a hotel, but the saving is a delusion. Western Europe is full of hotels, most of which, unlike British hotels, welcome lorry drivers and the expensive part of the bill is the food not the room. The room probably costs less than a driver who is using a sleeper cab spends during the course of an evening's drinking, and a driver who wants to cut down on his overseas living expenses should pay only for bed and breakfast and carry his own food and drink. It is obvious that a driver will get a better night's sleep in a hotel room than in a lorry park, while the public washing and toilet facilities available at the latter are not always good. The security advantage of sleeper cabs is rather theoretical as anyone trying to break into a lorry on a park is likely to be spotted, while thieves attacking a lorry parked on a remote layby were unlikely to be deterred by the presence of the driver. A fortunately very rare reason for not using sleeper cabs is that last winter four French drivers, caught by an unexpected cold spell in the Alps, froze to death, and last summer an English driver using a sleeper cab in Germany had a heart attack and lay dead for nearly a week on an autobahn rest haus parkplatz. In fact, anyone determined to sleep in the premium specification cab would find the driver's seat plus three-man passenger seat more
comfortable than the usual sleeper cab bunk, but the intended advantage of this seat arrangement is that it enables the driver to take short rests during the day, if desired.
The only significant differences between the Transcontinental cab and the cab described in this article are that the Transcontinental does not meet Swedish safety cab regulations, and there is no version with a space about 35 cm wide behind the seats. The Transcontinental cab was first shown at Earls Court last year in left-hand drive, sleeper-cab form, with a Scammell Crusader floor structure.
The advantage, apart from higher productivity, to the operator of a vehicle with a luxury cab is that it constitutes a major improvement in working conditions for the driver, and thus enables the haulier with premium specification vehicles to employ better drivers. The lorry driver in Britain has for decades been regarded as a second-class citizen, having very low wage rates and poor working conditions in the shape of old banger lorries, but now that most drivers on long-distance work are reasonably well paid, one with a premium specification vehicle enjoys higher pay and better conditions than the majority of sales representatives. Since the driver is the haulage operator's representative, an operator employing "driver representatives" who have the right approach to the customer has an advantage over an operator who can only employ the "don't blame me, I'm only the driver" type. This advantage would be particularly noticeable in overseas work. A TIR operator should be able to require a working knowledge of two European languages from his drivers, who would then be able to do the job easier and thus quicker, and would no longer compare unfavourable with their multilingual counterparts of other nationalities.
Reference has been made to the space required for the storage of tools and spares and a list of.the equipment carried by a fully equipped tractive unit towing third-party trailers illustrates the need for this. A complete set includes:— Toolkit sufficient to do simple roadside repairs with both metric and A /F spanners in toolbox; breakdown warning triangle; snow chains; tow chain; wheelbrace and bar; trailer winding handle with adapter for square landing gear spindle; 6-ton jack with 30 cm lift, and jack handle; adapters for various trailer air lines; assortment of trailer light lenses; torch; inspection light; wheelchuck; shovel; ladder; broom; handbrush; spare air line and Schrader valve end; spare mirror head; wiper blade; fan belt; complete set of bulbs; flasher unit, injector pipes (Simms fuel system); spare for any other known unreliable item; frost muffs for mirrors; tin of engine oil; rubbish bin; trailer number plate; first aid kit; fire extinguisher, handling gloves; maps; vehicle handbook and list of service stations; metre rule; wire cutters and so on plus the driver's personal luggage. Some of this is essential and some only desirable. Items like the ladder, broom and shovel would be carried on the catwalk or cab roof, but a fair amount of storage space is still necessary.
Next week: specifying reliable &arks.