International coach rescue
Page 18
If you've noticed an error in this article please click here to report it so we can fix it.
• by Colin Barnett
Worldwide Recovery Systems of Hertford has developed a recovery vehicle based on an Iveco chassis. The outfit was designed in-house by Tirn Hawkins, a former recovery operator with Worldwide's sister company, Lantern, which operates in the northern M25/southern M1 area.
Hawkins' objective was to design a vehicle to operate safely and legally, even with the long under-reaches required by modern coaches which form much of Lantern's work. It had to be highly manoeuvrable with effective monitoring and control of axle loadings, including the front axle which can become dangerously light. The addition of a heavy-duty steering and lifting third axle created a vehicle believed to be the first of its type in the recovery field.
Iveco had a suitable base product and was willing to provide advice and support for the many non-standard details. Thanks to this close liaison, the truck carries a full manufacturer's warranty on the original components and is fully type-approved.
As supplied by Iveco Ford, the original truck is a Spanish-built EuroTech MP180E42P 4x2 rigid, with a 51m wheelbase, intended for drawbar operation. One of the big attractions of the chassis was the narrow design, which gives the necessary clearance for the rear-steer set-up.
Power
is provided by Iveco's 420hp (309kW) 13.8-litre six-cylinder engine driving through a ZF 16S221 gearbox to the standard Rockwell air-suspended 13tonne drive axle with a 3.42:1 ratio. The gearbox is fitted with
a ZF Intarder, which is modified to operate in six stages via the brake pedal as well as the standard hand lever.
Suspension is two-leaf steel parabolic at the front, with Wabco ECAS electronic four-bellows air on the drive axle and anti-roll bars at both ends. The requirement for a second axle to carry a parking brake is met by fitting spring brake actuators to the front axle.
Strong chassis
The chassis work was carried out by Iveco Ford dealer and conversion specialist North East Truck and Van, on Teesside. The chassis rails were completely stripped From the gearbox backwards and strengthened over this length by welding an additional L-shaped flitch to the outside. The 10mm-thick flitches face inwards and project below the original rails to form an extra channel. Vertical anti-crush box sections are fitted inside the chassis channels at each rear suspension mounting point.
With the standard driveRne reconnected, the 16-tonne tag axle was installed. This is a Phoenix straight-tube self-steering device. its tube has a 130mm diameter with 28mm wall thickness, while the king pins are a sturdy 70mm in diameter. The self-steering includes positive locking applied automatically above 47km/h, with a manual override for reversing. The axle is mounted by a pair of leading two-leaf springs anchored to the very rear of the chassis rails with a short Panhard rod providing lateral location. Suspension on the tag axle is by a pair of 15-in inboard air bellows, with a single 16-in bag pro
viding lift. Total design capacity of the rear bogie is 29 tonnes.
No cross-member is fitted at the rear of the chassis; the resulting "walk-in" feature allows the elbow of the Boniface under-reach lift to be positioned within millimetres of the axle tube. This gives the truck one of its biggest advantages, as even very small forward gains at the elbow point reduce the steer-axle lift forces considerably.
Both rear axles are fitted with dual wheels to lessen the impact of tyre failure. Michelin 315/80R22.5 tyres are fitted all round, with XZE2s on the steer axles and XDE2s driving.
Crucial to Walker's concept is the monitoring set-up. The system for the rear axles comprises a pair of air pressure gauges, with the balance controlled by a dash-mounted switch which varies the pressure in the tag axle's air bags. The front end has a different need: to monitor the amount of weight being lifted off the axle by the weight hanging off the back; too much lift and the steering function tends to vanish.
A pair of in-cab lights are used, with neither illuminated when the front axle carries between 6,000kg and its plated 7,500kg. Between 4,01:10 and 6,000kg the green light shows, while a load below the danger level of 4,000kg activates a red light.
The vehicle can be driven in this state, but the operator will be aware of the need to go with care. The recovered vehicle can be observed in transit thanks to a pair of CCTV cameras feeding a dash-mounted screen.
Sideways recovery The Iveco's recovery equipment is centred on a Boniface Interstater Mk4F underlift which has 4.45m of outreach and a lift rating of 8,000kg at full extension. Aithough primarily designed for onhighway straight recovery, limited sideways recoveries are possible thanks to a pair of Superwinch 1130 14-tonne hydraulic winches and mid-mounted stabiliser legs. Power is provided by a layshaft-driven PTO operating remote tandem gear pumps.
The steel bodywork clothing all this kit is Worldwide's own construction. As Worldwide's trucks often travel overseas, a 1,000-litre dual compartment fuel tank is flexibly mounted above the gearbox. The semi-high-top sleeper cab includes twin bunks and a night heater, while the body contains heated washing facilities.
Almost all the Iveco's 20 tonnes unladen weight works for a living, with just 750kg of dead ballast being fitted behind the front bumper. The result is a truck plated at 38 tonnes GCW under C&IJ regs and 80 tonnes under STGO. The rear bogie can bear 21tonnes (C&U) and 26 tonnes (STGO), although this figure is expected to be increased soon.
CM was on board for the truck's first operational journey . Apart from some minor trimming of the rear bogie air pressures, it worked exactly as planned.
With a typical load of around 12 tonnes on the back the Iveco was extremely stable, while the 420hp and Intarter brakes took starting and stopping in their stride. Worldwide hasn't completed the costings yet, but the truck is likely to have a price tag of around 2170,000.