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A TRAILER WHICH TRACKS.

20th July 1920, Page 28
20th July 1920
Page 28
Page 28, 20th July 1920 — A TRAILER WHICH TRACKS.
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A Résumé of Recently Published Patents.

One of the outstanding advantages. of the six-wheeled vehicle, as represented by the Scamane11 and the Knox, is in re gard to its ability to negotiate, with its load, passages and yards which are a considerable source of trouble to the ordinary wagon towing the usual type of trailer. .The difficulties under whick the latter vehicles labour are particularly pronounced when it is necessary for much reversing to take place. In such circumstances, although much adverse criticism has been levelled at the six wheeler on account of the peculiarities of its steering, we do not recollect that any one has seriously put forward the view that the wagon and independent trailer has the advantage, or even that it is the equal of the newer type Of heavyload carrier.

Trailers which would improve matters in this regard are not unknown. They are usually designed to track in the same tracks as the towing (or teething) vehicle, . whether the latter is moving forwards or backwards. Trailers of that kind have from time to time been placed upon the market, but without hitherto meeting with any appreciation of the

benefits which they were euppoeed to confer. -Maybe the disability of the independent and ordinary trailer are not what they seem. At any rate, the trailer that tracks has not caught on yet.

There cannot be said, therefore, to be anything novel or strikingly original about the principles which underlie the trailar, which is. the subject of patent specification No. 144,132, ef which the patentee is A. Mond. It is, purely and simply, a. trailer which tracks. However, the construction appears to be on sound lines, and there can be no doubt bet that that/tare general adoption of trailers of this form, or seine similar kind, would be advantageous from several points of view, not least being that of the general user of the roads who has to wait, with the best patience that he can muster,. while a etearner and trailer, which have taken the wrong turning, reverse and turn round in the roadway. In the present design the ordinary Ackermann axle is used, fore and .aft if on a four-wheeled trailer, and for the ugly axle, of course, on a two-wheeler. The frame may be of any convenient form. That in the accompanying draw ing is of channel steel, with the flanges turned inwards. Above each axle, and 'firmly ecured to, the frame at each side, is a flat plate. The general body of it is at a lower level than that of the

chassis, being, as a matter of fact, disposed about midway between the lower

flange of the frame and the top of the axle forging. -Below each plate, and separated from it by a pair of distance . washers, is another and shorter one. The two, thus arranged serve as support for

what the patentee terms a whiffle-tree, and a pin through the centre serves as a bearing for that component:

The whiffle-tree is a triangular plate, somewhat irregular in form, the bearing being in the middle of its area. What may be termed the apex is directed to. wards the interior of the dhassis, and serves as an attachment for a steering rod by eehich it is coupled to one of B30

the stub axles of the trailer. A pair of stub axles are joined together, in the cueldmary manner with the Ackermann steering gear, by means of a. tiebar. To the two extremities of the base of the triangular whiffle-tree are attached rods or chains which at their other ends are coupled to the rear axle of the towing vehicle. They do not, however, bear the strain of the hauling. That is taken care of by a universally jointed drawbar of special construetion. A long triangular piece is secured at the two ends of its base to the axle of the trailer. At its front end is formed half of a universal joint. A smaller three-Sided component is seemed in a similar manner to the rear axle of the tractor, and this, too, at its apex, has also a part of a universal joint. The two portions of the universal joint are united to form the coupling between the two 'Machines. It will be noted that the drawbar is sufficiently rigid to serve either for towing, as when the tractor is moving

on forward gear, or for pushing, on those occasions when it may be necessary to reverse. The tracking mechanism of the trailer, of course, operates in either direction of motion of the combined unit.

On a four-wheeled trailer both axles are alike, and the whiffle-trees are united by a tie rod as shown in the drawing. The trailer may therefore be coupled to the tractor from either end, and both pairs of wheels are controlled by the steering gear in any event.

Detail Improvements.

W. T. Bell and F. J. Beetherion describe in specification No. 144,078 a method of holding the glands of the piston rod and valve rods of steam engines. A simple dog, secured and adjusted by means of one bolt, is designed ae rest with its outer edges on the projecting ends of the glands. Those ends are semi-cylindrical sothat the pressure of the dog always acts in line with the axis of the rod. All or any of the glands Ir may be tightened as equired by the h simple manipulation of e one nut.

The non-skid fitting for pneumatic tyres which is described in specification No. 144,150, by S. T. Buchanan, Of Aberdeen, U.S.A., is interesting. A chain with elongated links is located on the inner side of the feline of the wheel. U-shaped links at intervals are attached to this chain, and they support bars, which are of substantial section, so as to be practically rigid. They are of such a shape that they will clip Ile tyre very i

closely when it s in the semi-flattened condition which it assumes when near-to contact with the ground. In that way the strain of holding the non-skid when it is in operatien is taken from the supporting chain, it being practically gripped by the tyre within it. In. order to reduce the speed at which the surfaces of friction discs work, D. N. Quertier interposes a single gear reduction between the engine and trio-Lien gear. The patent is numbered 144,180

The non-skid fitting which is described by H. C. Smith in epecification No.

144,107, is a block which fits between two adjacent spokes and partly surrounds them. It thus forms a substantial and practically rigid attachment for the non-skid chain. It is claimed that it Ls equally applicable to all types of wheel,including the wire wheel.

W. G. Smith, in No. 144,192, utilizes a ring of rubber, secured against the felloe of the wheel, as a splash guard.' It is niade the same size as the tyre, and wears down with it.

An improved arrangement of electrical self-starter is described in No. 144,220 by a German patentee. 'The object of the modifications described is that of eliminating the risk of damage to the mechanism owing to the starter being switched OR while the engine is running. By grooving the front faces of the engine cranks, and drilling holes which connect these grooves up to the interior of the hollow crankpin, again drilling holes between that interior and the surface of the pin, Powell Bros., Ltd., in No. 144,231, attain the lubrication of the connecting rod by simple means,

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