Dissimilar Demountables
Page 57
If you've noticed an error in this article please click here to report it so we can fix it.
IN your report on the meeting held by the South Yorkshire I Section of the Institute of Materials Handling, at which Mr. A. H. Carter read his paper "Transport and Materials Handling—Road Vehicle Development," there were certain references to the Dinosaur system which, together with the Dumpmaster and Dumpster systems, we are now manufacturing in this country.
Reference was made to: (a) "The Dinosaur system was relatively costly "; (b) "Its use increased the taxation of the vehicle -; and (c) " Because the Dinosaur was tilted to a steep angle when loading, it could only be applied for certain types of goods."
As, in some ways, this information is misleading, I arn taking the opportunity of dealing with these points:—
(a) Invariably new techniques and methods involve increased capital expenditure, but resulting operating costs show considerable reductions arising out of increased efficiency and lower labour charges. The Dinosaur vehicle with its simple hydraulic equipment is naturally more expensive than a normal commercial chassis, but in many applications it will permit fleet operation with a reduced number of vehicles. With virtually no idle time for loading and unloading, it is possible to attain an exceptionally high utilization factor for the mobile unit.
(b) The slight increase in taxation involved by the higher tare is a very minor aspect in the overall annual operating cost, and is quite insignificant when compared with the labour saving of approximately £1,000 a year for the driver of each vehicle rendered surplus by the intro. duction of the Dinosaur system.
(c) It is inferred that the container can only be loaded on to the chassis by elevating to a steep angle. This is not so. The Dinosaur is the only, self-contained vehicle that can load and unload its own body on to or off the ground, a dock, a flat rail car or against any height of dock (up to chassis height)—it being possible to fit adjustable legs to each body container.
It is only when the body container is picked up from or set down on the ground that significant elevation takes place and, as the maximum elevation is approximately 17°, this could hardly be considered a " steep angle." Irx addition to this complete flexibility, in picking up and setting down its Own body, the vehicle is capable of further elevation to approximately 45° for complete discharge by tipping—for appropriate material.
Having clarified these aspects of the Dinosaur system, I would support Mr. Carter'sclaims that " an interchangeable body system offers the best solution to many traffic problems and can provide a better means of goods handling than the articulated vehicle.The Dinosaur system allows for interchange of dissimilar as well as similar bodies—the one vehicle can handle a variety of flats. totally enclosed or open bodies, stake-side bodies or even tanks.
Maindy, Cardiff. W. P. WARREN, Director, Powell Duffryn Engineering Co., Ltd.
Third-axle Conversions Again
I HAVE read with interest the letters on the subject of I third-axle conversion vehicle performance compared with that of the three-axle machine designed by chassis manufacturers and fitted with a " slogger" engine. In the laden condition the three-axle conversion with its usual engine is no match for its 10-litre opponent on any up-gradient. Even a slight head-wind would reduce the speed of the "conversion " considerably, since it has no reserve of power to overcome this, and a change-down is more than likely with a consequent increase in fuel consumption.
It is true, however, that on a downhill run, or with a tailwind, those conversions which have a high maximvm governed engine speed can and do reach speeds in excess of 50 m.p.h. But can they stop?
The majority of the third-axle conversions are equipped with servo-assisted hydraulic, brakes, the master cylinder of which was. initially designed for two-axle braking, and to provide a safe reserve of volume to cater for lining wear and drum expansion due to heat. To expect the existing brake system to operate on an additional axle can be extremely dangerous, for pedal travel is increased, thus reducing the available margin of safety Furthermore, the increase in gross vehicle weight reduces the handbrake efficiency considerably. It is impossible for a single-pull handbrake to be efficient at 20 tons g.v.w. unless it is power-assisted.
With regard to " Minimog's " statement that the mass producers have ,virtually extinguished the heavy fourwheeler, I would suggest 'that this is almost entirely due to legislation which restricts the speed of a drawbar trailer combination to 20 m.p.h., and requires a driver's mate to be carried.
The heavy four-Wheel tractor and maximum-payload semi-trailer is still a very popular combination.
Euxton, Lancs. " ANGLO-SCOT.''
[Most third-axle conversion specialists nowadays augment the standard braking system by providing an additional servo and master cylinder—E}..