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by Ron Cater, AMInst BE ONE thing is evident at

Earls Court this year and this is that the quality of trailer manufacturers' products has continued to improve. At the last Show, there was already a definite improvement in the quality of units when compared with those shown in preceding years, but although the trend was encouraging even then, the advances made between '68 and the present exhibition are far greater.

Some of the most significant improvements are among the multitude of container carriers. It is apparent that makers have learned from mistakes made on earlier skeletal designs which resulted in drooping or broken bolsters, disappearing twistlocks, and containers damaged by sagging frames. And it is evident that most of the newgeneration skeletals will not suffer from such shortcomings.

The widespread bogie has maintained its popularity despite tyre scrub. Of the heavyweights here this year, the great majority are equipped with widespread bogies. And there seems also to be a bias towards the use of low-profile tyres. Whether this is from choice or because there is a national shortage of tyres, I am not sure. Of all the widespread types, however, there are only two which have steering axles, each axle originating from Italy.

One other maker of running gear—who also builds trailers but is not showing any at this exhibition—also has a steering axle with an Italian origin. None of the steerable types of standard trailer sports a full steeringbogie, each model having only one castorsteered axle.

Fewer pure skeletal trailers are on show than in recent years. It seems that the need for an all-purpose vehicle which will fulfil all the needs of a haulier, be it to carry general cargo, to do TIR work or mount various lengths of container has overshadowed all others; a large number of vehicles reflect the industry's ability to fill the need.

There is a significant swing toward multipurpose TIR vehicles several of which, built for Scandinavian operators, show just what can be done if an operator is prepared to pay the price.

Such a unit, shown by Peak Trailers, has been built for a gross trailer weight of 31 tons to operate at 38-ton gvw. It is 40ft long and features 20in. x 6in. main-frames which are flitched with a 4in. x 0.5in. plate along the section of the frame reduced in depth over the fifth-wheel coupling. Heavy tubes, 6in. in diameter, and 4in. x 2in. rsc are used to form cross-members at strategic points in the frame construction while 4in. x 21n. Ibeams form the cross-bearers set at 27in. centres throughout the length of the trailer. Three kingpins are fitted to permit several types of tractive unit to be coupled to the trailer, the positions of the pins being 3ft 6in., 4ft 2in. and 5ft 2in. from the front. The pins, of the folding type, are secured within the rubbing plate by spring-loaded catches.

Another unusual unit from Peak Trailers is the Mammoth suspension. This is built both in tandemand single-axle versions and features independent coil-sprung swinging arms. It is shown as a unitized tandem bogie suitable for mounting on tank or frameless van-bodied trailers and the like. Commercial Motor carried out a number of stability trials with this suspension during 1969 and 1970.

A second unusual TIR semi-trailer, from J. Booth (Trailers) Ltd, is equipped with a three-axle bogie and mounted on under-slung springs. The resultant floor height is only 37in. and within an overall height of 4 metres this allows for a clear interior height of no less than 10ft. The capacity of the vehicle is 2968 cu ft. The three-axle bogie, mounted on 8.25 x 15in. tyre equipment, provides for weights of 7.5 tons on each axle, a total capacity of 22.5 tons at the ground. Intermediate decks, which are fully load-bearing, can be fitted at any height to operators' requirements. The small diameter wheel and tyre equipment places a 40 mph speed restriction on the vehicle when fully laden.

What is probably the most versatile TIR ever seen is York Trailers' Europa. It is 40ft long fitted with demountable TIR bodywork, twistlocks and a substantial platform, and can be used for all kinds of general haulage. As it also has a dual-position kingpin and a sliding bogie, one can juggle the overall spread and the axle and kingpin imposed loads so as to make it suitable for use with numerous tractive unit configurations. Twistlocks for one 4011-long container or two 201:1 containers are fitted, these being fully retractable.

A clear trend at the Show is that most trailers are generally designed either as maximum-capacity single-axle units or maximum-capacity tandem-axle units. If they do not fit into these categories, then it is a safe bet to say that their design is aimed at the 16-ton-gross market. The maximumcapacity three-axle trailer is conspicuous by its absence. Four years ago almost every maker was showing a three-axle unit. This Show sees only one running-gear of this type. Obviously, the swing towards the widespread bogie has taken the biggest toll of the tri-axle market. After all, why use three axles when an adequate ground weight can be obtained with a widespread tandem? The three-axle trailer bogie was, of course, introduced before the maximum permitted overall length was increased to 15m (4911 2.6in.) from 13m (4211 7.75in.) at which length it was almost impossible to fit in the 3811 outer-axle spread required to run at 32 tons on four axles. Five-axle combinations qualify for 32 tons gross at only 32ft outer axle spread.

Only one major company now shows a non-reactive suspension of complicated design. Dyson has a boxvan designed for Hoover equipped with its Grandon suspension, a throwback to the BRS contract for that type of unit which heralded the introduction of the many non-reactives shown in 1964.

York and Dyson show converter dollies for use with standard haulage semi-trailers. These units have taken on a new importance since the rescinding of regulations requiring that a mate be carried on a vehicle hauling a drawbar trailer, The dolly shown by Dyson features a hinged drawbar and is mounted on 8.25 x 15in. Michelin tyres. The unit carries its own compressed-air reservoir and brake valve and triple diaphragm brake chambers operating I2,25in. x 7in, Moss brake units. It also has a link-stay to hold the drawbar rigid when the unit is being towed light.

York also shows a dolly unit but in this case the drawbar is formed by the main frame being swept inwards to form an A-frame. Any discrepancies in drawbar height caused by changing load or road conditions are accommodated by the rocking trunnions of the fifth-wheel. On this unit there is, of course, no need for a link-stay instead it has a support leg built in to hold the coupling at hook height when it is parked. The York unit is of 10 tons capacity and is fitted with a York 22, 5001b axle and a York Big D fifth-wheel coupling.

Those concerned with heavy haulage will find the unit shown by King Truck Equipment Ltd extremely interesting. It is a doubleended drawbar trailer with a low bed and a capacity of 60 tons, and it steers on all its eight axles. Unlike some of the multi-steered units which have appeared over the years, the King unit—based on the German firm of Scheuerle's designs and built under licence— utilizes hydraulics only for the powering of the steering but not for the transmission of the steering effect between the front and rear bogies.

This is done purely by mechanical linkages formed by ball-ended rods and chains and rods. A drawbar can be attached to either end of the vehicle to permit it to be towed or pushed and pulled in either direction, but, of course, in one direction there is a slight detraction from the braking power of the two-leading-shoe brake units which are used. Both the swan-necks are detachable, the centre load-carrying bed being lowered hydraulically to ground level to permit bogies to be removed and the bed to be loaded. Any number of beds can be supplied for use with the bogie assemblies giving the trailer a stillage-like capacity, of particular use where numerous heavy moves have to be made over a short distance when one tractor with a pair of bogies could handle a number of beds which could be loaded or off-loaded while another was in transit.

A new low-loader introduced earlier this year is shown by Crane Fruehauf. This is a detachable bogie-type of vehicle and is suitable for operation with payloads of 18/20 tons within the C and U Regulations and up to 25-ton payloads when having a Special Types authorization.

A feature of this unit is that it can be supplied with either the bogie or the swanneck quickly detachable. The bogie used is the standard CF DC2-18 two-spring unit which provides for the maximum articulation of the running gear essential for negotiating rough ground. CF also shows another completely new semi-trailer, a light alloy, semimax-section seven-compartment spirit tanker.

About half the numerous tippers feature the Villiers radial-arm-style of tipping. With this system the running gear is rigidly fixed to the tipping body while the tipping gear is mounted on the fifth-wheel. Connected between the fifth-wheel and the sub-frame of the running gear, is a braced, doublemembered framework hinged vertically at each end. As the body is tipped, this member goes into tension and together with the body and the tipping rams forms a triangulation which is inherently stable. Vehicles employing this system are shown by Neville Industries and Neville Truck Equipment.

The rubber suspension developed by NTE for use with maximum-capacity tippers of the radial-arm type is utilized on a unit shown mounted on Super Single tyres; it is fitted with York type 92 axles. The suspension rubbers are in the form of the triple-sandwich chevron rubbers mounted slightly off-vertical, canted in towards the top and angled outwards. The axles sit almost level with the rubbers and have a total range of movement of 2in. both vertically and laterally. The suspensions are carried in a pair of walkingbeams formed in the shape of Ms, the units nestling tietween the outer legs and the central V of the M. At the bottom apex of the M, a large section bearing runs on nylon bearings which are lipped to retain the lubricant. On the main shaft, which runs through the centre of the walking-beams, are loose wear-sleeves to protect the main shaft and these can be easily replaced.

To counteract the braking torque developed in the axle, a pair of radius rods situated beneath the axles are connected to the pivot shaft housing; these are connected through plain spherical bearings by pushfit pins retained only by a split pin.

The axle and suspension manufacturer, Rubery Owen-Rockwell, has a large number of units on show. Almost all of the smaller builders using conventional-type running gear have RO equipment on their products.

Although Hands Trailers, of Letchworth, no longer exists, it has left its mark at the exhibition on a number of bodybuilders' stands. The Hands Neway running gears are still being made by the other Hawker Siddeley firm—Gloster Saro—and a number of the Hands A and B (Weightsaver) range of trailers are being manufactured by Crane Fruehauf. CF bought all the designs when Hands was wound up.

Some of the ancillary trailer equipment is of considerable interest. Northern Trailers show a steered rear-axle widespread bogied container-carrying flat trailer, which has a very nice screw-type hand-operated parking brake unit. This is made by the Extra Special Engineering Co Ltd, of Fleetwood, Lancs, and is an enclosed unit having a wo—rm and wheel winch to tension the brake cables. Brockhouse has another neat handbrake unit and claims that it is completely waterproof. It emits two cables connected to the brakes on both axles.

More trailers this year have parking brakes on two axles and in at least two instances running gears have four-line air systems, the extra line powering the releasing cylinders or spring brake units on the trailer axles, permitting these to be operated from the tractive unit cab for service parking and providing an outfit with multi-axle parking brakes. Dyson is the firm which has produced these units—one being shown by Dyson as a running gear and the other mounted on a YEWCO tanker for Esso. This unit, also featuring a DysoriNiberti castor steered rear-axle on the widespread running gear, now has a load capacity of 10 tons giving a total widespread bogie capacity of 20 tons. This bogie is mounted on a Dyson/Dunlop Stabilair air suspension which, with the Hands Neway and the Scammell units, make up the full complement of air suspensions at Earls Court.

New exhibitors of trailer equipment have to work their way from stands in the gallery to a more prominent place on the ground floor and this year there are two new exhibitors up there. These are J. Booth (Trailers) Ltd, and an Irish firm, Arran Trailers. Booth, shows the three-axle low-level TIR mentioned earlier while Arran, which makes trailers of the German Blumhardt company's design under licence, shows an on/off road unit

with a capacity of 20 tons and a trunnionsprung bogie with 13-leaf springs and a removable kingpin. The bogie is capped by a pedestal to raise the bed of the trailer to provide a very high ground clearance. The vehicle is 33ft long and has a 1.125in.

tongued and grooved Keruing deck laid longitudinally. The platform is stake-sided, each side being made up of four sections. These are removable and are stiffened by top-hat-section steel posts.

Also shown by this company is an office/ trailer-cum-workshop. This is a drawbar unit mounted on twin-wheeled axles and has a ball-bearing turntable.

M and G Trailers have gone still further along the line in multi-purpose trailers and show a coil/container/flat-bed trailer. This thin has developed a reputation for building a good coil carrier but specializes in building to customers' specifications. For the first time, M and 0 shows a low-loader. This is a 24-ton gvw unit with an overall length of 27ft 6in. and a lower-bed length of 18ft. Once again many of the details are the result of customers' requirements.

A style of vehicle that has appeared in recent years is the dump trailer. This vehicle is a robust scow-ended unit most suitable for the rough life of site work. Its design throws the maximum amount of weight on to the driving axle of the tractive unit, to a large degree overcoming the age-old problem of traction inherent when using artics for off-road work.

Neville Truck Equipment Ltd shows a 24-ton gvw 15 Cu yd version of its Uni-Dump model. NTE's founder, George Neville, introduced this type of vehicle to the UK market and this latest version should interest tipper operators.

Not all the semi-trailers at Earls Court are from the heavy brigade. Tasker has a small auto-coupled unit plated for a gross trailer weight of 6.8 tons; this is of simple construction having 5in. x 2.5in. rolled-steel I-beam main-frames and rolled-steel angle side raves. The Tasker DS coupling is used with the secondary braking requirements passed by mechanical linkage through the . coupling.

Also shown is the American-designed Stricicvan which Tasker and its associate company, Cravens Homalloy, have jointly developed for the UK market. Although the specification is extremely high, its price is claimed by the maker to be highly competitive.

Like the Europa shown by York, this trailer is equipped with an adjustable bogie permitting movement in increments of 6in. over a total distance of 3.5ft. Provision is also made for alternative kingpin positions giving the vehicle a good deal of flexibility as to which tractive units can haul it. A total load imposition of 16 tons is permissible through the Strickvan kingpin without any alteration to the design.

I learned from the Tasker team that the firm had quite recently installed a new automatic welding machine which is being employed in the fabrication of main 1-beams. With the restrictions placed on companies using rolled I-beams by the steel industry, both with regards to the dimensions of beams available and the extended delivery times, it is becoming more and more important for them to fabricate their own units. In any case, there is a lot to be said for the flexibility of design one has when making one's own beams.

It is quite surprising to a shrewd observer to find that trailer makers in general fail to standardize in the fitting of brake and lighting plugs. Some are so fitted that they are thoroughly protected from accidental damage, others are extremely vulnerable. The same might be said for some makers' ideas on protecting rear lighting equipment, on trailers designed for roll-on/roll-off opera tions, from pilfering. Some of the devices shown would be better suited to housing a canary rather than deterring a determined pilferer of lenses and bulbs.

Most firms are now making a good job of fitting landing gear. In former years many of these have been braced fore and aft only, with a tie bar linking the two legs. Now the majority have triangulated stays, in many cases having quite correctly dispensed with the tie bar.

Only one transversed twin-aided unit is shown this year—it is BTC's and is the wellknown Four-in-Line. While almost every other maker has discontinued this type of vehicle, a spokesman for BTC told me that there was still considerable demand for it.

The frameless van has become quite popular. They range from units designed for operation at 16 tons gvw right up to the Strickvan and the York Freightmaster, being designed so as to be suitable for uprating to the highest gross train weights envisaged.

Weeks and Co (Engineers) Ltd is the only firm to show a trailer embodying a stillage handling system; the firm has introduced a new model with a capacity of 15 tons to its range. It is mounted on narrow track axles and takes the form of a chassis subframe on which is mounted a parallelogramtype second frame. Mounted between the sub-frame and the top frame are tripleextension hydraulic • rams which, when extended, raise the top frame. The unit is used in conjunction with stillage frames also built by Weeks and was initially conceived to reduce the demurrage charges made by a dock authority on a timber importing company. The vehicles have been steadily developed to fulfil the requirements of over highway running and now incorporate threeline air-pressure braking, a fully compensating bogie and all other C and U Regulations requirements.

From 13. Dixon-Bate, the Chester-based firm that builds small, special-purpose trailer equipment, comes the Uni-Box semitrailer designed so that both the body and the frame are load bearing. The suspension arrangement is interesting in that the hubs are mounted on stub axles carried on trailing arms. Suspension is by Aeon rubber springs and because there is no axle the floor level has been kept right down giving an unladen loading height of only 17in.. making it ideal for the sort of local delivery work for which it is intended. The vehicle on show has been specially designed for the North Western Electricity Board for use in delivering domestic electrical appliances. Other trailers that can be seen here are all of the two-wheeled drawbar type, one being a 220gal capacity tanker, the others a 6cwt 85 cu ft box trailer and a 25cwt cross-country general-purpose vehicle.

All these last mentioned vehicles feature overrun braking, the two heavier models having 10 x 1.75in. brake units and the lighter one, 7 x 1.25in. units.

Highway Trailers (Great Britain) Ltd is showing for the first time models from its 75 Fleet Special Range. Among these are two dual-purpose units, two flats and a skeletal.

The skeletal is a 25 tonnes model designed for operation in Denmark. Like many other units at Earls Court, it is fitted with singletaper leaf springs.

Of the Highway dual-purpose units shown one is a flat with container locks for one 20ftlong ISO container, the other vehicle is a flat/coil carrier and this features the wellproven Highway Vee-shaped coil-well construction. Highway is one of the companies taking special care to ensure the service couplings are well and truly protected from accident damage.

Northern Trailer, Pitt Trailers and Highway all show extremely light semi-trailers. Highway has a 32-ton platform, 37ft-long semi-trailer decked with 1.25 in. Keruing flooring and 16.5 x 7in. brakes; it has an unladen weight of only 3 tons 11 cwt. The Northern single-axle 24-ton-gvw model mounted on low-profile tyres weighs only 2.5 tons; the 32ft-long Pitt Tandem 4, a 24-ton tandem with single-wheel and tyre equipment, has an unladen weight of 3 tons 8cwt.

Customer influence shows very clearly on most of the semi-trailers on show, and as I commented at the beginning of this review, the quality of most exhibits is better than in previous years. I have been delighted to see that most makers have forsaken the extremely dangerous pointed roping hook in favour of a blunt-ended unit but I cannot be enthusiastic about some of the headboard assemblies. I saw only one flat platform vehicle with a step-tread fitted to assist the driver climbing on to the platform; apparently the others are made by manufacturers who still assume that all drivers are 21 years old—and athletic!