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our on Demountable Bodies
Direct Savings Derived From a New Loading System Will Offset Capital Cost In Two Years By P. A. C. Brockington,
A.M.I.Mech.E.
COMBINED use of four vehicles and seven demountable bodies has, in recent months, coped with grocery deliveries which formerly required six rigid vehicles of comparable capacity. The experiment has been carried out by G. Wright and Son (Dorchester), Ltd., Dorchester, Dorset, who estimate that the direct savings derived from the system will offset capital cost within two years. This does not take into account the value of more obscure advantages, such as earlier delivery times and more efficient organization of warehouse movements.
The new method of loading is based " on the Cargon system, developed by Fisher and Ludlow, Ltd., but has a number of original features. Mounted on an Austin forward-control oil-engined 7-ton chassis, a container body can be removed and replaced with a substitute by two men in 10 minutes. At the Wright depot containers are loaded direct from the warehouse with the aid of hand trucks and pallets.
Although the change from conventional methods was accompanied by some teething troubles, there have been no • major difficulties.
The use of a weighbridge for checking all outgoing loads is an aspect of the new operation which has special importance to the drivers. Because of the time now saved by 7 the rapid turnround of vehicles, drivers can normally complete a day's work without overtime. This has reduced their earning capacity on the original wage scale.
But the weighbridge is being used to formulate a bonus scheme to compensate for loss of earnings and to increase efficiency by relating payments to tonnage carried and unloading time. It is expected that, on average, drivers will earn the same wage as before, without overtime.
Operations Over Dorset and larger centres on the boundaries of neighbouring counties. Runs are organized on a regular weekly basis and, in the case of longer deliveries, with multiple drops, one run occupies an entire working day. Over the week, however, two runs are frequently covered by the same vehicle in a day, which, in a typical case, represents an increase of vehicle utilization of 100 per cent.
Supplied by Fisher and Ludlow, Ltd., the steel mounting frame for the box container bodies is equipped with 25 wheels of 4-in, diameter, arranged in five longitudinal rows on roller bearings. The wheels are supported by five runners of Cor-Ten corrbsion-resistant steel on the vehicle chassis, and the body is firmly clamped to the chassis for road operation.
In pteparation for unloading, the vehicle is backed up to the single-exit dispatch bay. The height of the chassis runners is adjusted automatically to the height of the deck during the final 18 in.
of moyement. This is done by two V-type guide members, which contact rollers on the rear of the vehicle.
This method of vehicle alignment obviates the use of jacking to raise the vehicle wheels to the required height. The principle was evolved by the Wright company, and the gear was built by H.C.B. Engineering, Ltd., Totton, the makers of the light-alloy insulated container bodies.
Height Adjustment
A body being removed from a vehicle is nOrmally empty, or lightly loaded, and the height of the rollers is greater than the axis level of the V guides. The upper guide members, therefore, contact the rollers and depress the chassis to the level of the deck, so that the vehicle runners line up with similar steel runners embedded in the deck concrete.
Arranged transversely to the access ramp, a sunken section of the warehouse floor accommodates a traverser-type trolley. This is supported on rails and enables the body to be moved manually to any part of the section. It also allows it to be transferred to a higher floor. on the far side, to one of five sets of steel runners set at right angles to the traverser This layout provides four loading positions in addition to a washing bay equipped with a high-pressure washing gun. An Avery weighbridge, located between the entrance deck and the washing bay, records the weight of the complete load, including the traverser and container. All loads are routed over the weighbridge.
Body Location
The body is located at the front of the vehicle chassis by two angle-type clamps. which automatically engage projections on the body to prevent vertical and forward movement. Two lever-operated screw-type clamps are employed at the sides, and two more special-type screwclamps at the rear. Here, adjusting screws bear on pivoted arms in contact with angled locating plates on the container.
Mounted on rolled-steel-joist pillars the V guides are free standing, so that no part of the load on the guides is transferred to the warehouse building structure. When the vehicle has been lined up for container transfer, a hinged flap is lowered to bridge the gap between the two sets of steel runners. Alignment of the vehicle, when it is being backed up to the warehouse deck, is facilitated by two raised strips of concrete, which act as tyre guides.
Additional help comes from two shallow concrete slabs, forward of these strips, shaped to give drivers an indication of the correct position at the front end. A limited amount of practice enables drivers to back into the V guides without repeated shunting.
The container has an internal length of 14 ft., is 7 ft. wide, 6 ft. 6 in. high and weighs 12 cwt. It is estimated that the auxiliary gear adds 6 cwt. to the weight of the vehicle, compared with arigid boxvan with an all-aluminium body. The extra weight also represents The approximate difference between lightalloy and normal composite construction. but mainly bulk loads are carried, which weigh far less than the maximum payload. The special gear increases the floor-level height by some 3 in., but this is offset by a similar reduction in wheel clearance by the employment of lighter road springs.
Two aluminium roller shutters are fitted at the rear of the container, the shutter on the left being of reduced width. This gives access to a smaller compartment, separated from the main one by wire-mesh partitions. This is used for storing special packages and empties. The shutters are constructed from one piece of corrugated section, which dispenses with hinges. They are easy, however, to operate.
Insulation is provided by 11 in. of expanded polystyrene filler between the double skins of the sides and roof. The rolled-and-hardened exterior aluminium panels have a dimpled finish and give a pleasing appearance.
Other body details include a wooden floor and an interior light. Current is supplied by the vehicle battery when the container is mounted and by a Davenset transformer, connected to the mains, when the light is required for loading in the warehouse.
The grocery fleet is operated in conjunction with four van-sales vehicles which distribute cooked-meat products. These are Austin 1-ton vehicles equipped with B.M.C. 2.2-litre oil engines. A day's run may involve up to 80 stops, but the vehicles average as much as 30 m.p.g. and have a high reliability record.
Because of the frequent stopping, lubricating oil in all the Wright vehicles is changed after 1,500-2,000 miles, and it is a boast of the directors that none of the company's vehicles emits black smoke. All maintenance is performed in the garage, which is heated during the winter by oil-burning equipment supplied with old sump-oil.
Colour Experiment
An interesting psychological experiment has been carried out with the colour scheme of vehicles in the grocery fleet. In an effort to attract the attention of the public and emphasize the cleanliness of the vehicles, light-coloured paintwork is used throughout. But no two vehicles have the same livery. The principle is also applied to the containers, with the result that 28 colour combinations are possible.
It is contended that the policy is appropriate where operations are restricted to a relatively small area, and the company name is well known. Variation in appearance creates added interest, it is claimed.
This is in contrast to the example of a concern delivering to centres in distant parts whcro their name would escape notice unless it was backed by repeated visual impact of similarity of appearance.