TECHNICAL
Page 35
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Made to measure
TRACTION has been improved on a DAF 6x2 by rifting a Primrose Hi-lift axleload transfer unit, claims North Yorkshire haulier Ken Longthorne.
Working out at Hebalen on the moors north of Skipton, often with a drawbar trailer combination, good gradient performance is essential in his operation.
The device, switched electrically from the cab, is controlled by a solenoid valve which allows compressed air to pass into twin convolution bellows clamped between the saddle plate on the drive axle and a bridge plate across the chassis frame.
As the bellows expand weight is transferred from the trailing axle to the drive axle which is said to restore tyre grip and allow the vehicle to climb any gradient within the capability of the 150kW (201bhp) engine.
The braking system is protected by a pressure regulator placed in the line between the air tank and the Hi-lift. This determines the maximum pressure in the bellows and limits operation to when the tank pressure is above 448kN/sqm (65psi).
A lamp mounted inside the cab indicates to the driver when the system is in use.
Ken Longthorne often uses a Parkhouse 8.84m (29ft) three deck livestock container mounted on the platform body ' of a DAF and a similar unit at 5.79m (191t) on his Dyson drawbar trailer which accommodates a total of 32 cows or 600 lambs at one time.
The increase in traction is especially useful in off road conditions where previously delivery would not have been possible. CRANE Fruehauf has produced a lightweight urban semi-trailer design for Bass Charrington which it has conceived after a year of operational trials and a computer analysis of high cost areas in the maintenance of' the brewer's trailer fleet.
Now 220 of these trailers have been ordered and will go into service with nine companies in the Bass Charrington group.
Originally, the urban trailer design had to satisfy four urgent requirements, These were a light but strong construction enabling the trailer to be used under any possible restrictions of the Dykes Act, a standardised vehicle for all the company's group requirements, a longer life than trailers which the company has been operating and that its various sections should be built so that they could be repaired within times set by Bass Charrington's fleet engineers.
After a year's trial of the 7.62m (25ft) single axle aluminium alloy trailers, more design improvements were made.
The main frame, which is of 'I' beam steel, has aluminium alloy rear and intermediate cross-members, side raves, headboard, sheet rain superstructure and stirrup steps.
With a gross train weight of 16 tonnes (15.2 tons). the vehicle is plated for 14 tonnes (13.8 tons) gross and can carry either kegs or bottles. Unladen weight is 2.6 tonnes (2.56 tons).
To improve the ride char acteristics, the trailer is fitted with CDIS soft ride nine-leaf springs and Aeon rubber assistance giving a 63mm (2.5in) deflection.
One repair which Bass Charrington 'ound to be parti cularly cost17 from a labour view point vas the replacement of the d ack floor which is subjected to a great deal of • wear and tem r.It is now made with cross-boards in slide out buttressed SE 2tions.
As a piece s damaged, it can be slid out ar d replaced, If the whole deck needs renewing this can be done quickly, says CF.
Additionally strengthening has been added to the corner pillars and the aluminium side stanchions which have been repositioned for strength.
At the sides, removable steel bars can be replaced at 228mm (9in) and 304mm (12in) inter vals to suit the load being carried.
Other alterations to the trailers include rubber flap mounted rear lights, a toughened front hanger bracket and skid brackets.
One final saving, says CF is that the trailers require no painting.