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Match Tipper Payloads to Vehicle Characteristics
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-SAYS COMMERCIAL DIRECTOR OF 162-STRONG HOVERINGHAM FLEET
OPERATORS of all types of heavier vehicles throughout the country will appreciate the view of Mr. W. J. Sheppard, commercial director of Hoveringham Gravels, Ltd., Hoveringham, Nottingham, that "existing legislation regarding maximum gross loads enforces the use of lighter vehicles for work that could be more efficiently performed by lorries of more robust construction." Elaborating the theme, Mr. Sheppard claims that this represents a payload penalty of around 11-2 tons in the case of a maximum-load four-wheeler, if the most suitable type is employed for the transport of sand and gravel.
Mr. Sheppard believes that, in the main, operators and vehicle manufacturers mutually agree there is need to match rated payload to the characteristics of the chassis and running gear to give the heavier vehicle an appropriate advantage. He makes the plea that this weight of opinion should be recognized in practical form by the Minister of Transport.
Complicated Problems
Organization and maintenance of 162 vehicles in the Hoveringham fleet are complicated by the necessity to distribute the lorries according to variations in need between the 18 quarries operated by the parent company, who control six subsidiary concerns and four associated companies. The fleet consists of 39 eight-wheelers and nine articulated outfits of Foden manufacture, and 10 rigid Albion sixwheelers. The remaining 104 vehicles are all four-wheelers, comprising 37 Bedfords, 27 Albions, 17 Fodens, 12 COmmers and 11 Thames Traders. The smaller vehicles include a number acquired in recent take-overs and many of these are sub-standard with regard to mechanical condition, compared with the high standard of the original .fleet.
Fifty Leyland Comet CS3.2R four-wheelers will shortly be supplied by Ford and Slater, Ltd., Leicester, on a hire. user basis over a period of 18 months, which will be used partly to replace existing vehicles and partly to augment the total. This scheme should obviate major overhauls and will eliminate selling difficulties. It is envisaged that some 200 vehicles will be in regular service when the Leylands have been integrated into the fleet. Mileages average from 900-1,100 weekly, the eight-wheelers engaged on long-distance work covering the greater mileage.
Quarry and fleet operations are supervised from a northern region headquarters -at Hoveringham and a southern region office in Wyboston, the two regions being geographically divided by a line between The Wash and the Bristol
Channel. Quarries in the northern region are at Newark, Nottingham and Colwick in the Trent Valley district (in addition to Hoveringham), Brandesburton in East Yorkshire, Finningley, near Doncaster, Lound, near East Retford, Chorley and Wigan in Lancashire, and Welford near Rugby.
In the southern region the group operates quarries at Tillingham in Essex, Rainham in Essex, Kintbury, near Newbury, Stanton Harcourt, near Oxford, Emberton in the Newport Pagnell area, Bourton on the Water and Chadlington, near Stow-on-the-Wold, as well as Wyboston. A traffic manager controls fleet operations regionally in both cases.
On average, about five per cent, of the distance covered represents site work, the most severe conditions being found on road-building areas. Vehicle operations vary from round trips up to 80 miles and short-distance deliveries within a radius of five miles. A substantial proportion of the traffic takes the form of runs between processing plants
(Below) Hoveringhatn operat the quarries and pre-mixed ate nine Foden articulated outfits — 'an enterprising concrete plants, whilst the conversion of vehicles that remainder normally comprises were originally too heavy the transport of loads to road to provide an economical building and erection sites, payload for their rated capacity." When engaged in inter-plant
runs, the vehicles are loaded and unloaded on level ground and no undue stresses are imposed on the vehicle chassis or tipping gear, a qualifying factor being the free-running property of the material.
When vehicles are feeding a road building site, the drivers are given strict instructions not to discharge the load unless the surface is level. The only accidents that have occurred have been the result of ground subsidence during the tipping operation.
A large variety of earthMoving equipment is employed at the quarries to feed the processing plants and to load vehicles; these include a number of Foden four-wheeled road vehicles specially converted in the Hoveringham workshops to operate as dumpers.
Maintenance and running repair schedules are prepared by the technical staff at Hoveringham and most of the major overhauls are performed in workshops on the Hoveringham premises, which are separate from those used for servicing repairs to static and mobile plant.
In addition to the workshops, there are well-equipped stores, a bodybuilding shop, a machine shop, which is nearing completion, an injection-system department, a tyre shop and a greasing bay. Routine servicing and some major overhauls are undertaken in repair depots at the quarries.
Power units of the Foden vehicles include Gardner 6LW and 5LW oil engines, and Foden Mk. 2 and Mk. 3 twostroke units. Major overhauls are normally carried out after the vehicle has completed some 180,000 miles, and it is noteworthy that in a typical case the crankshaft journal 'wear of a two-stroke engine does not exceed 0.0005 in. In the case of an eight-wheeler, the Gardner 6LW unit has a minimum fuel consumption of about 12 m.p.g., whilst a Mk. 2 two-stroke gives a minimum of about 11 m.p.g. The relative lightness of the two-stroke is considered to be a favourable factor.
One Lubricant
Eight-wheelers are equipped with the Foden 12-speed overdrive gearbox, which has highly favourable wearing characteristics and affords particular advantages for arduous site operations. Although not specifically recommended by the Foden company, the gearbox is filled with four gallons of lubricant instead of the specified 2+ gallons. Sump oil is changed in this case at 4,000-mile intervals, whereas changes are made after 2,000 miles in the case of the Comrner and Bedford engines, because of their reduced sump capacity.
An interesting practice is the use of Mobiloil Delvac Supplement 1 10W/30 engine lubricating oil for all types of power unit. Experience has shown that this lubricant is suitable for universal application. The use of a single grade simplifies stock control, reduces storage space and obviates the selection of an incorrect grade when a sump is refilled or replenished.
Standardization of lubricant is also applied to the two-pit greasing bay, where the use of three grades of lubricant covers the transmission requirements of all the vehicles serviced. A sunken workshop connecting the two pits is extended into the open at one end. The bay can accommodate two eight-wheelers, and 19-20 vehicles are serviced nightly by two fitters. Apart from four corner mounted Tecalemit grease pumps and hose reels, all the equipment is of Weaver manufacture and includes two Drain-0Matic oil dispensers. Used oil is fed to tanks mounted outside the building.
Worm-type back axles have been lubricated with Mobiloil Sovac 17 oil for the past nine years, and during this time no axle has failed in service. Other types of final drive are lubricated with Mobiloil GX.90 hypoid oil, and a Grade 140 straight mineral oil is used in gearboxes. Hub bearings are filled with Mobiloil M.P. lithium-based grease.
The strict enforcement of regulations by local councils relating to spillage on road surfaces has necessitated a special study of this problem and has resulted in the application of scow-ended tipping bodies to some of the Foden rigid vehicles. These are Neville sectioned-type U-shaped bodies of bolted construction having a capacity of 13 cu. yd., which are operated by Pilot twin-ram triple-telescopic under-body lifting gear. giving an angle of tip of 55 deg.
The robust construction of these bodies is regarded as a particularly favourable feature, and their use obviates corrosion problems as well as increasing the payload. Compared with a timber body of an eight-wheeler, the weight saving is 10 cwt., whereas in comparison to a steel body the saving is 8 cwt.
Only modification to the Neville standard body assembly on eight-wheeled Fodens is the use of steel mounting frame runners in place of the light-alloy type, the frame being supplied by the Foden company. With this combination, fractures of sub-frames have been completely eliminated. Company technicians consider that a rigid mounting frame structure is essential to the avoidance of distortion and favour steel members.
Many of the Foden vehicles are fitted with plastics cabs, which afford an appreciable saving in weight and are also relatively easy to repair. The front bumpers are again of plastics material and were originally located flush with the body panels. However, this allowed severe bump stresses to be transmitted to the cab 'structure, and the bumpers were later mounted on brackets below cab level to obviate damage from this cause.
The nine Foden articulated outfits represent an enterprising conversion of vehicles that were originally too
heavy to provide an economical payload for their rated capacity. These are equipped. with Gardner 5LW engines. After conversion in the workshops by reducing the wheelbase and fitting a Davis fifth-wheel coupling, the vehicles are used in conjunction with York trailers equipped with alloy bodies and steel sub-frames both of which are manufactured by the Pilot company, the additional payload being about 3 tons. With this payload advantage, the engine is slightly underpowered and experiments are being made with turbocharging to raise the output.
It is of special interest that keeping the vehicles in service may well depend upon the success of these experiments, which involve the use of a Simms turbocharger. This is mounted on the gearbox behind the cab, which necessitates a relatively long pipe connection to the inlet manifold. Bench-test results indicate that an output increase from 94 b.h.p. at 1,700 r.p.m. to 127 b.h.p. at the same speed can be expected. The long intake pipe appears to offer no disadvantages.
Tractors of the articulated outfits are also employed to haul trailers of the flat-platform and low-loading types, the latter being Dyson 30-ton units. Operation of the turbocharged engines will, therefore, cover a wide variety of running conditions.
Body Modifications Steel bodies fitted to the four-wheelers have been _modified to give reduced length and an increased height, the object of the modifications being to vary weight distribution and obviate the risk of loading the rear axle above the regulation 9 tons. When standard bodies were used, it was necessary to check the load on the rear axle as well as the weight of the complete vehicle before a delivery run, and in a typical case part of the load had to be removed to reduce the weight on the back axle despite an acceptable total.
Some of the heavier vehicles are equipped with Homalloy light-alloy bodies constructed of tongued-and-grooved sections, and these are fitted with +-in. special light-alloy floors. Outrigged under-body rams of Pilot manufacture are employed, whilst the timber bodies of the Commer chassis are equipped with Telehoist underbody SL7 singleram tipping gears. The Bedfords have steel bodies and Autolift front-of-body rams. About 50 per cent, of all the bodies used are U-shaped.
Employing Commer lorries equipped with two-stroke engines represents an experiment with lightweight vehicles, due for replacement after about two years, to test the economies of such a policy. So far, the maximum mileage covered by one of these vehicles is about 20,000, and wearing properties cannot be compared with those of other makes. The power units show no signs of undue wear and operate economically.. Timber bodies are fitted because of the contemplated limitation of overall life.
Strict attention is given to tyre maintenance, which is the sole responsibility of a specialist fitter. Michelin tyres are used throughout the fleet, the original Michelin Metallic type now being superseded by Michelin X and
XY type covers. Eight-wheelers in current service are equipped with Michelin Metallic D.20Y tyres, which are dimensionally equivalent to the 10.00-20. tyre and replace the standard size of 9.00-20. This " over-tyring " may, it is considered, partly explain the very favourable mileages
obtained. On average, this exceeds 50,000 miles, compared with 40,000 in the case of a four-wheeler and an articulated outfit mileage of 60,000.
The company have maintained comprehensive tyre records since standardization on Michelin tyres nearly five years ago and have proved that their eight-wheeler tyre cost is less than 1.8d. per vehicle mile. This figure takes into account the use of remoulded covers. Some Michelin D.20Y covers have been remoulded four times.
Although tyre pressures are checked this is a precautionary measure only, loss of pressure being very unusual over a period of 12 months as the tyres are equipped with Michelin Airstop tubes.
Tyre maintenance is supervised at all quarries by Michelin service personnel. The X tyres are preferred to Michelin Metallics because they afford a better ride, particularly when the vehicle is unladen. Any trouble previously experienced in the form of "gravel rash," caused by small gravel particles penetrating to the bead area through the valve slot, has now been eliminated by fitting a suitably shaped plate over the slot.
Converted to Dumpers
Conversion of five Eoden four-wheelers equipped with Gardner 5LW engines for operation as dumpers included equipping the vehicles with a special dumper cab, front bumper, rear wheels and air cleaner and a dumper body supplied by the Pilot company. Detailed features of the equipment include Aeon rubber-spring check buffers mounted on brackets in line with the main frame members, which relieve the tipping gear of shock stresses. The Pilot twin-ram underbody U.3 lifting gear gives an angle of tip of 50 deg.
Details of garage equipment include a 40-gal. cleaning tank equipped with an electrically driven suds pump to supply high-pressure jets arranged along the sides of the tank, Fletcher Miller Gensol No. 10 cleaning fluid being employed. This equipment is used in conjunction with a Wickham steam cleaner.
Designed by the garage foreman and constructed in the workshops, an hydraulically operated press is built of• standard lifting gear parts and has a useful capacity of
50 tons. The injector department is equipped with a Merlin pump analyser and injector spray tester.
Many drivers have upwards of 15 years' service to their credit, and it is symptomatic of the management's encouragement of responsibility and initiative that several drivers have graduated to higher positions in the organization. A driver bonus scheme based on the gross earnings of the vehicle is designed to promote keenness in the reduction of loading and turn-round times.