AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

BODYWORK FOR SIX-WHEELERS.

9th November 1926
Page 92
Page 93
Page 94
Page 92, 9th November 1926 — BODYWORK FOR SIX-WHEELERS.
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

The Advantages of Six Wheels to a Vehicle for Load Carrying. Some of the Applications of the Two Types—Flexible and Rigid Frames.

rip HE larger the vehicle unit the lower are the costs 1 per ton-mile, providing that full loads can be lound. But if the size of the ordinary four-wheeled van or lorry be -increased so as to permit a very large load to be carried, an excessive weight is. concentrated on the two .axles, especially upon the rear one with consequent damage to the roads. This drawback may be overcome by increasing the number of wheels used, so that the weight is better distributed. The four-wheeled trailer drawn by an ordinary lorry is used as a simple means of ensuring economy in transport, but, by comparison, the same load can be carried more compactly on a six-wheeled vehicle and the load can form a useful means of securing adhesion of the driving wheels.

'Flexible and Rigid Types.

The six-wheeler is made both as a flexible and rigid type. The typical flexible six-wheeler consists of a

more or less short coupled tractor, on the back end of which is mounted a turntable for carrying the front end of a two-wheeled trailer. This type a vehicle has a definite legal status, for, under the Heavy Motorcar (Amendment) Order, 1922, it may now travel at 12 miles an hour instead of being limited to 5 miles per hour, the axle weight of the trailer may be up to tons and for all the axles 22 tons, while an overall length up to 33 ft. is permitted.

The rigid six-wheeler is a comparatively recent introduction to this country. It has been designed chiefly to meet the demand for passenger vehicles of larger seating capacity, as the flexible six-wheeler is, from the technical point of view, a vehicle drawing a trailer, and, therefore, cannot be used for the mounting of bus and coach bodies unless it weighs under two tons laden. With the rigid six-wheeler the two rear axles are assembled closer together than the two front axles of a

D2 . flexible six-wheeler, because they are both used for driving. This has the advantage of a better tractive effort, wheelspin is almost impossible and skidding is reduced considerably. As the two hind axles are coupled together by the type of spring suspension adopted, the vertical play is thereby reduced and less wheel-arch clearance is necessary, As axle weight is reduced, pneumatic tyres may be used with safety for public-service work, apart from the fact that the punCture of two tyres on the same side of the chassis is very • unlikely.

The Flexible Six-wheeled Lorry.

Let us consider various types of six-wheeled vehicle. The flexible six-wheeler has a driver's cab mounted on the tractor portion, while the loading unit is mounted on the trailer. The cab, being separate, lends itself to standardization. There must be sufficient clearance in a horizontal plane to allow for the turning movement of the trailer on its wheel plate, as well as in a vertical plane when the vehicle is-negotiating bad roads, or is on the crest of a humpback bridge or similar road. conditions. For this reason, six or eight inches clearance

is allOwed between the back of the cab and the front of-the main portion of the body, whilst the back of the cab slopes forward at the top as in the Carrimore sikwheeler, or the front of the loading unit is curved as in the 8cammell six-wheeler to a radius having its centre corresponding approximately to that of the turntable.

As the hind axle is not a driving one and there is only the •brake mechanism to consider, there is plenty of scope for the mounting ..of almost. any style of body required, whilst the hind axle can be placed far enough back So as practically to eliminate rear overhang.

With a plain platform body mounted, a loading area of 21 ft. to 22 ft. 6 ins, long by 7 ft. wide can be obtained, suitable for loads of seven to eight tons and for sided lorries and box vans up to 12 tons, whilst for cable drum and machinery haulage sbecial patterns are made to carry loads up to 20 tons, The length of

the body is often increased to over 27 ft. ind up to. the legal limit of width.

Side Loading Facilities..

A useful feature of the flexible six-wheeler is the large amount of free body spaca between the middle and hind pair .of wheels, so that it is a simple matter to arrange for side as well as end loading. Side loading is usually a great convenience, even with a small van, but it is more so when the vehicle is long. Although the straight trailer_ frame is found suitable in some trades, there is no doubt that the cranked or drop frame is better, because then the advantages of low as well as side loading are combined. The height of the forward portion of the body is determined by the height • of the tractor chassis and the style of turntable adopted, but so long as sufficient clearance be allowed behind the tail end of the tractor the whole of the remaining portion of the trailer may be cranked down. Often the height of the hind wheel determines the lower floor

• level, but since there is 100 or more square feet of floor space, the body can be built inside the wheels and the top of the wheel-arch or guard arranged so that it is on a level or just below the floor level. The floor height may also be reduced at least five inches by the use of a wheel-arch. This will not interfere seriously

• with easy loading if side doors or drop sides are fitted, nor, bearing in mind the siz,e of the body, will it reduce its capacity to any appreciable extent. If outriggers are bolted to the side of the chassis, then the thickness of the bottom frame is reduced to a minimum as well as the height of the floor.

The Well Floor.

A straight frame may be used and a very useful well floor constructed by building the lower part of the body

between the bind wheels and carrying the well as far forward as is required. This form of construction introduces a ledge on either side at the frame level, but is not objectionable for many kinds of loads. It would appear that the use of the cranked axle is not favoured for the hind axle of the flexible six-wheeler, but if adopted it would give an extra low well floor. Dished or splayed wheels might also be adopted so as to allow a wider body to be designed, without increasing the track. Smaller hind wheels would also allow the floor to be built lower.

Detachable Hoops.

A very useful pattern of general-purpose side-loading body with drop frame has a loose sheet supported on hoops and longitudinals acting as ridge poles. Steel hoops of channel section are bolted to the tops of the side stanchions. The hoops can, if necessary, be re

moved and stowed away in front. Drop sides are provided, having hook-shaped hinges so that they can easily be removed if necessary. The stanchions are also removable so that the vehicle. can, if desired, be converted into a flat platform lorry.

' Cable Drum Transport.

The flexible six-wheeler is unsurpassed for carrying such heavy and cumbersome articles as electric eable drums and machinery. The trailer frame is of the drop pattern and is made as low as the hind suspension allows. A wheel-arch or even side members. arched over the hind axle are not likely to interfere much with loading, as the drums will lie in 'single file and not be wider than the chassis. With -a low floor only a coin-. paratively short hind ramp is required for loading the drums. On the forward end of the trailer is mounted a hand winch, which rolls the drums into position and then retains the ramp in an upright position, acting as a safeguard, but the drums, of course; are held in position by strong' wedges and other fastenings. The ramp may also be held in a vertical position' by means of rods with hooked ends.

Pantechnicons.

The six-wheeled 'pantechnicon is a capaciOus affair equal in size to a couple of small rooms of a suburban villa! In America, in localities where there are no restrictions as to length, six-wheelers of truly mammoth proportions are in use, and in this country bodies 27 ft. 6 ins, long by 7 ft. 6 ins. wide and 8 ft. high are in service, representing a capacity of 1,650 cub. ft. The panel area available for writing display is equivalent to that of a street hoarding!

Six-wheelers for the Brewer, Market Gardener and Farmer.

The skeleton-sided body forms a suitable pattern for brewers' use. Mounted on a drop frame, the whole of this part of the side is divided into a pair of hinged doors, whilst another pair gives access to the higher portion over the turntable. On a Scammell lorry of this type the doors can be easily lifted off their hinges without swinging right back. The body is 22 ft. 6 ins. long and has an approximate capacity of 60 barrels. The brewer also uses the platform lorry with or without side stakes and chains, and also as a drop-frame platform lorry with wheel-arch. As the brewer uses a ladder for unloading, the low loading line is a great labour saver. The skeleton, or cage-sided, body Is also favoured by the market gardener and with suitable modifications can be designed for transporting livestock. A comparatively large number of pigs or sheep can be carried by means of a double-deck body.

Tanks and Tippers.

The flexible six-wheeler is suitable for mounting large tanks up to a capacity of 3,000 gallons carried on cross-bearers secured to the trailer frame, or the tank Itself forms the connection between the middle and hind axles and no trailer frame is required. Tipping bodies are also mounted up to a capacity of about 30 cubic yards.

D4

The Six-wheeled Bus And Coach.

Although 'the rigid six-wheeler is used for goods transport, there is no doubt that its chief field of activity' lies in the direction of providing economical passenger service. With a lowloading chassis,, bodies, of the largest capacity may be mounted safely with the advantage of less road wear. The rigid six-wheeler is also made up by adding an extension frame and another axle and pair of wheels. This method is adopted 'for. passenger vehicles of both medium and small seating capacity, because a six-wheeled chassis is not only a method of mounting a large body scientifically, but it has advantages for almost any size of body. Asa singledecker the six-wheeler is often built as a 40-seater, the advantage being that the bulk of the load is carried on two hind axles and four wheels instead of half that number, whilst the amount of rear overhang can be kept within reasonable limits, or be made evein. less than with the ordinary four-wheeled chassis..

As a double-decker the rigid six-wheeler is built to a seating capacity varying from 54 to 68 seats, witheither normal or forward steering. A recent design has not only a covered top, but also an enclosed staircase. Two firms which specialize in the rigid-frame six-wheeled double-decker are Guy Motors, Ltd., and Karrier Motors, Ltd.

The rigid six-wheeler offers similar facilities for the. mounting of medium and large-sized coaches. It also gives much scope for the design of the luxury type of saloon coach with a larger seating capacity than is possible on the four-Wheeled chassis, with plenty of legroom, luggage accommodation, and every convenience of modern road travel.

Tags


comments powered by Disqus