HINTS ON SALVAGE WORK IL
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A Number of " Tips " which May be of Use to Repairers are Contained in This Article. By " Vim." ,
AS PROMISED in my previous article on salving commercial vehicles that have broken down
• on the road, I will now give some hints and tips, acquired by actual (and sometimes painful) experience, on getting them off the rocks and into the repair chop.
Ordinary mechanical derangements not involving towing need not concern us now. I am going to refer only to absolute breakdowns and wrecks. Quite possibly many of the garage proprietors who read what follows will find that they have learnt nothing fresh, but I believe that to those who have not yet had a lot to do with the heavier types of automobiles some of the suggestions put forward may come in handy one of these days.
A good-quality steel wire rope takes a lot of beating as a towing medium. The breaking strain of a i in. diameter rope of this type is from 4 to 8 or 10 tons, according to the number of strands and quality of the steel. The steel wire rope is elastic to some extent, and therefore itself absorbs some of the shock of getting away, but great care should always be exercised to avoid kinking hecauSe this weakens it seriously, also it must not be permitted to become suety. For towing a vehicle the brakes of which are for any reason out of action, the only possible medium is a bar or pole, which will take thrust as well as pull, so that the towed cannot over-run the vehicle that is towing. I have used 3 in. by 3 in. ash for a towing bar With complete success, and have pulled some very heavy lorries with it. As a matter of fact, the tensile strength of fair-quality ash is, I think, in the neighbourhood of a tons per square inch, and its crushing weight a-bout 4 tons per square inoh, and I suppose the size mentioned would handle almost anything on the road at present, but it is iraportant to remember that it is not easy to keep a piece of timber dead straight for long, and that a slight curvature will weaken its resistance as a whole to a compression strain, such as occurs when the front car is suddenly checked, thus causing the towed vehicle to be pulled -up by thrusting on the bar. It is also most important to bear in mind that the towing vehicle's brakes have double work to do. A towing bar must be furnished with suitable universal swivel joints at both ends to allow for road inequalities and turning movements
or with loops by Means of which the ends may be hooked or roped to the vehicles. The steel straps which secure the universal joints to the bar, or form the loops referred to, should be carefully forged so as to fit the bar snugly, and should be well bolted in their position through holes drilled with the metal end pieces in situ to insure that the bolts fill the holes in the wood perfectly.
It is always advisable to carry on the break-down lorry, besides the towing rope or bar, a quantity of stout hemp rope, especially for dealing with difficulties such as these: If the break-down lorry gets stuck on a hill while towing another vehicle, either because of the severity of the gradient or because the greasy state of the sos,d's surface prevents the wheels from gripping, it will usually be found that at no considerable distance ahead the gradient eases off or there is a nice, gritty piece of surface. Uncouple the front car and let her run ahead to the more favourable spot, add the extra lengths of rope, and let her pull from that place in comfort. This generally does the trick, and the rope can be shortened again at once. I recollect on one occasion using what must have been nearly 100 yards of rope before
could get a move on the heavy van we were hauling: we had been stopped by other traffic on a hill, and our lorry simply could not get off again with her burden, but the extra length of line enabled us to proceed to the brow of the hill, where our car was on the level and had not her own weight to worry about; and so, by gentle stages, we managed to bring the other to the top. Sometimes it is practicable to use the off-side camber of the road to relieve the towing car of some of its labour until a move has been got on the whole outfit, after which the power available is usually sufficient to keep going. Starting away is always the worst part of towing.
An extra long tow rope will not infrequently solve the problem of removing a, ditched or bogged lorry from its temporary resting-pla,ce, because, with its aid, the towing car can utilize any piece of surface in the vicinity that is most favourable in point of view of hardness or of down gradient. If necessary, the hauling can be done a foot or so at a time, the rope being shortened after each effort, so that a. few
feet of good going for the tower will suffice. A pulley rigged to a tree may be necessary to give the right angle for pulling, or, in certain circumstances it may be desirable to place a few rollers under the rope, to reduce friction between it and the road.
Do not forget that a bogged oar—that is, a car which has got on to soft ground and cannot stir because its rear wheels can get no grip, and merely fly round as soon as the clutch is let in—can often be extricated from its difficulty by its own power, with the assistance of a. couple of lengthseof strong rope. If the back wheels are shod with twin solids, tie each rope to one wheel, by passing it through the pair of spokes that is just. about to enter the groove scooped by the wheels in the ground, and knotting it over the division between the tyres; then work the ropes under the front wheels and attach their other ends to some fixed object, such as a tree, or even to another car, directly in front of the stranded vehicle. To induce the ropes to go under the front wheels, jack the latter up one at a time, or cut away the soil. The diagram will explain what I mean more clearly than words will convey. If the clutch be now let in gently, the back wheels will act as winding drums and will travel along the ropes. Once, when I had nothing whatever on which I could depend for fixing the forward ends of the ropes. I tried tying them to the front wheels in the manner shown in the diagram, thus converting the bogged lorry into a four-wheel-drive vehicle for the time being! The operation had to be repeated twice before she was clear of the soft spot, but it answered all right. If the hubs of the rear wheels happen to be prominent, it is occasionally possible to tie the ropes to the spokes and make the hubs serve as winding drums, but a man will be wanted to watch each of them, because they will not carry many turns of rope, and prompt action with the scotch is requisite to prevent the whole show slipping back to its old position, should all the turns come off with a rush, as they are inclined to do.