OPINIONS FROM OTHERS.
Page 27
Page 28
Page 29
If you've noticed an error in this article please click here to report it so we can fix it.
The Biqar invites correspondence on all subjects connected With the use of commercial motors. Letters should be on one side of the paper only and typewritten by preference, The rifgd of abbreviation is reserved, and no responsibility for views expressed is accepted.
The Weighing of Long Wheelbase Vehicles.
The Editor, THE COMMERCIAL MOTOR.
[1986] Sir,—With reference to your recent article dealing with the Ransomes conversion attachment for motor lorries, we should be interested to learn the
method employed for ascertaining the weight on each individual axle. Presumably the platform of the weighbridge was of a convenient length to allow of the middle axle being weighed while the front and back axles were on the ground at each end. [This assumption is correct. —ED.]
It is a fact, well-known to weighing machine manufacturers and ethers, that weights arrived at by weighing first one axle and then the other, and adding the two together are invariably misleading and inaccurate. To some extent the reason is that, owing to play in bearings or couplings, but .principally to the impossibility of. maintaining the ground at each end of the weighbridge dead level and in,the same plane as the surface of the platform, another factor besides gravity is introduced, viz., leverage.
If the wheels resting on the ground are ever so little higher than those on the weighbridge, a portion of their load will press downwards on to the weighbridge instead of vertically down on to the ground, thus increasing the load on the axle that is being weighed. The lorry is then Moved across the weighbridge until the front wheels are clear and the back wheels on the platform. If the ground under the front wheels slopes upwards, or if the wheels are on a hump, so raising them slightly above the level of the platform, a portion of their load will again be thrown back towards the weighbridge, and the two weighings added together will give a considerable overweight.
Conversely, if the ground, as is usually the case, falls away at each end of the weighbridge to keep off surface water' part of the load on the axle being weighed will be transferred by leverage to the axle resting on the lower ground, and in this ease short weight will be registered.
The action of the load may be compared with water in a rectangular tank. If the tank is level the pressure of water on the bottom will be uniform,' but if the tank be tilted at one end some of the water will run down to the lower end and increase the weight at that end, leaving the other end lighter. If, however, the whole tank is on the platform of a weighing machine, whether it be tilted or not, the correct weight will be registered, because both ends are weighed together.
The importance of weighing all the wheels of a vehicle simultaneously will thus be realized, and this applies equally, whether the vehicle has four wheels or'six wheels.
Many of the now fairly numerous six-wheeled lorries have a wheelbase exceeding 27 ft. Obviously, a weighbridge with a single platform of sufficient length to take these would be very expensive. We have, therefore, designed, and are supplying, a special weighbridge with two platforms in tandem suitably spaced to accommodate vehicles of every wheelbase from two-wheeled carts to the largest six, wheeled lorries. We shall be pleased to send particulars to any of your readers who are interested.--Yours faithfully, Wm. HonosoxAND SONS (WEIGHING
• MACHINISTS), LTD. C. F. WILLIAMS. Salford, Manchester.
The Clearing-house and the Haulier.
The Editor, THE COMMERCIAL MOTOR.
[1987] Sir,—I must apologize for asking further hospitality of your columns, particularly as I feel that my letter, No. 1985, in your issue of August 8th, deals with many of the points raised by " The Skotch " in his article appearing in the sam.e issue, but his article calls for further comment.
For certain obvious reasons I naturally dislike criticising the National Road Transport ClearingHouse, and, candidly, I detest writing on the sub• ject of clearing-houses at. all, because it savours of propaganda ; anti, indeed, my letters generally result in numerous additional applications from hauliers— just what I least desire. I repeat that my company is inundated with requests from hauliers, and prospective hauliers, for work, and my advice to the latter is always the same, viz., for goodness' sake "
don't"; market is already overcrowded.
We coud comfortably handle a further 200 tons of traffic daily were it available at our rates, but it can only be had (thanks to unscrupulous competition) at rates which are not a paying proposition for the average haulier, and we decline to touch it. Last week we were offered 85 tons to Birmingham at 35s. per ton, and declined it. It might suit vehicles of heavy-carrying capacity, but it is useless for 4-5tonners, and my point is that the principle of cutting rates simply because one van carry deuble.that of his neighbour is entirely. wrong. It is unjuSt to the smaller unit which must necessarily stay with us, and, indeed, unjust to the larger unit, because the net result is that the latter' in many instances' after conveying a double load, fares little or no better financially than the former at the standard rate. If the trading public had no use for the smaller vehicle it might be a different proposition, but there are, comparatively speaking, few regular consignments of 8-10 tons from one customer. Certain clearing-houses and traders will shortly be praying for the smallertype vehicles they have pushed off the roads ; in fact, they already feel the pinch. Our hauliers are frequently chased around London by gentlemen in taxicabs bidding for their services for traffic which these gentlemen have accepted at ridiculous rates and experience difficulty in moving. However; to return to the National Clearing-House, which " The Skotch " says "to some extent he is championing because they have come right out into the open and boldly advertised the terms which they offer to both parties." I have no desire to interfere with the liberty of the subject, but from the public point of view I consider the announcement was a complete fiasco. It simply quoted rates for 1-ton consignments for which, it was alleged, the railway companies usually applied their Class 2 and 3 rates, and as, in many instances, the rates differed very widely between the same points, i.e., one rate for traffic out of London, and a much higher figure into London for the same commodity, the position was absurd. For example, if Mr. Brown, of Nottingham, sends 1 ton of his commodity to London, he has the satisfaction of knowing that perchance the same vehicle Will bring from Mr. Smith, of London (a keen competitor), a similar consignment at 15s. per ton less than he (Mr. Brown) has paid. Or, if Mr. Brown has a factory in each place, he pays 65s. per ton from Nottingham to London and 50s. per ton from London to Nottingham (a point for London hauliers). RailWay rates are a maze without a plan, and abound in anomalies ; but I think the above beats all. Again, it is a practical impossibility to quote an economical rate to cover commodities in Classes 2 and 3 without making qualifications. Indeed, it is so with Class 3 alone. Just one example—a customer of ours despatches Class 3 traffic in cases and pays a certain rate. He also sends the same goods loose, i.e., in packets, the latter requiring a box-van lorry ; consequently, a 4-ton vehicle in this case only conveys 3 tons of actual traffic, and it would simply be absurd providing a more expensive vehicle and carrying 1 ton less of goods for the same sum of money ! Also, there are the thousands of exceptional rates in operation on the railways to be taken into consideration, to say nothing of the " unwritten law " appertaining to railway charges.
Of course, to quote a comprehensive rate by road is one matter and its consequences another. So much for the information to the public for 1-ton lots in Classes 2 and 3 (presumably applied to any sender irrespectiveof consignees), but where are the rates for Classes 1, 4 and 5 in 1-ton lots, and, what is infinitely more important, the rates for consignments exceeding 1 ton, which, of course, predominate?
I repeat, what I oft-times have said, that so long as road transport is in competition with the rails, the railway rates and conditions must be the basis for road rates ; the public demand it, but for the railway companies to publish their rates and conditions (goods and passenger train) from London to a single destination (say Birmingham) would neeessi tate a brochure of the proportions of The Commercial Motor, and it is, therefore, impossible for the road transporters to issue a similar guide.
I fail to see how "The Skotch " can contend that the announcement of the National Clearing-House provides both sides with their.terms. In my opinion, all that matters was conspicuous by its absence. Incidentally, there was no 'mention of terms to the hauliers, and the rates most called for are those for consignments exceeding 1 ton. " The Sketch" admits that a rate of 358. per ton to Bristol is useless for consignments under 5 tons, but is that not the rate quoted for 1-ton lots and the natural inference that lots exceeding 1 ton would be subject to a less rate?
Is" The Sketch" aware that 1-ton lots by road are in a minority ? And how, may. I ask, can he honestly champion the cause of one of my competitors solely on the grounds that they have given publicity toall their fates, when, in fact, they have only quoted a fraction of them? My quarrel 1S. with him, not with my competnors. I think your readers will agree With me that before he can champion the cause of this or any other concern, he should at least know the rates at which they convey the bulk, and not a fraction of their traffic; and, acting on his principle of boldly publishing rates, surely your readers are entitled to the full facts—or none at all.—Yours faithfully, WALTER GAmmo7KB, Managing Director, WALTER GAMMONS, LTD.
Will the Solid Tyre be Superseded?
The Editor, THE COMMERCIAL MOTOR.
[1988] Sir,—In The Commercial Motor for August 8th you ask the above question. In your editorial you state that you believe that sooner or later—and probably the former—the ordinary type of solid tyre will lose its present pre-eminent position and retire into the background.
In your article you do not state why this evolution must take place in the .near future, and therefore I think the readers of The Commercial Motor should know the reason why existing solid-rubber band tyres must soon be put on the scrapheap.
Very few people seem to realize that existing heavy commercial chassis cannot possibly have their tyres, wheels, axles, axle springs and differentials sprung unless by means of a shock-absorbing tyre. In other words, if such heavy chassis are shod with existing types of solid rubber band tyres, then every one of these unsprung parts must always remain unsprung parts under all running conditions which means that the foundations of the roads and bridges are prematurely destroyed, ehassis upkeep is increased, and the effective speed of the chassis is reduced. In fact, the only possible way of springing the unsprung parts of existing heavy types of chassis, referred to above, is by means of an efficient shack absorbing tyre, which ,gives, say, up to an inch in road contact under minimum load and in. up to an inch, as and when required, under maximum load or shock. The existing solid rubber band tyre can only give or flex in road contact up to, say, I of an inch when running _under ntaximunt load, and the softer the rubber used in the mantifacture of the tyre (in order to obtain greater give), the greater is the objectionable "wave or bill" of rubber created in front of the tyre when running on the road, thereby reducing the speed of the vehicle and increasing petrol consumption per mile. This objectionable wave orhill of rubber which appears in all existing solid rubber band tyres is enormously increased if the tyre is manufactured with soft rubber instead of with hard rubber, with the result that when any phassis is travelling at or over 15 miles an hour (which is greater, than the speed the -rubber .wave-infront .of the tyre can travel at) additional objectionable road shocks must be created when travelling even over a fairly good road, because the hill of rubber has to be mounted. .
. Another serious flaw which existing solid rubber band tyres all have is that their speed is more or less limited to the actual speed, or frequency of repose, of solid rubber, and, as the speed of confined air is 1,500 per cent. greater than that of rubber, it is impassible -for a solid rubber band tyre ever to have the speed of a tyre having a suitable cushion of confined air formed beneath or within itscentre
line. In other words, the flaws of all existing solid rubber band tyres are as follow.—
(1) Objectionable resilience (or bouncing 'quality) which compels the tyre to bounce all over the road instead of clinging to the road. "
(2). Very poor shock-absorbing qualities under maximum load, with practically none under minimum load, because the give in a solid tyre in road contact is only in. to jin., instead of being from
in. to 1 in.
(3) Limited speed, because of the fact that the speed of solid rubber band tyres is more or less limited to the speed or frequency of repose of solid rubber as compared with confined air.
(4) Solid rubber band tyres are built to carry the maximum load, instead of 'being built to carry the .minimum load efficiently.
I am quite satisfied that the commercial tyre of the future will have :—
(la) No objectionable resilience (or bouncing quality) and will be constructed to cling to the road under all running conditions.
(2b) Good shock absorbing qualities under mznimurn load and greatly increased effective
strength automatically when carrying maximum loads or overloads.
(3c) Greatly increased speed, because of the fact that no objectionable wave or bill of rubber will be created in front of the tyre when running on the road, because the extreme tread or centre line of the tyre will be constructed to give free spread, and to swallow up road inequalities instead of mounting them, under all running conditions. (4d) The shock-absorbing qualities under minimum load will spring every unsprung part in every type of heavy chassis in the future' either when it is running empty or lightly loaded, a thing absolutely impossible to-day, with solid rubber band tyres.
In Your editorial you state that two factors at present militate against the present use of giant inflated tyres—namely, (a) first cost and maintenance, and (b) the wheel drop in the event of a large inflated tyre bursting or puncturing.
I am satisfied that these difficulties will be 'overcome in the commercial inflated tyre of the future by the manufacture of an inflated tyre which cannot possibly drop in road contact more than, say, 2 ins. —Yours faithfully, ENGINEER. . London.