• USEFUL TIPS ABOUT BRAKES.
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Our Driver and Mechanic Readers Air Their Views on an All-important Subject.
AFEW notes about brakes are always in season, and are of equal interest to drivers of all kinds of vehicles. Amongst the letters which we have received on this subject, that from " H.P.," of Glasgow, is the most workmanlike. He describes a simple method of making a brake gear to be carried on a wagon, but designed to operate the brakes on a trailer drawn by that wagon. It is so arranged that it can be operated direct by the existing hand-brake lever, but is, of course, only applicable in cases where the connection between wagon and trailer embodies a rigid tow-bar and hook.
The particular wagon to which this brake gear was fitted was equipped with a pair of towing hooks, similar to the War Office pattern, and located at the rear end of the wagon, one at each side of the frame. The towing hooks were removed, and their supporting brackets made to do duty as bearings for the brake-shaft. The latter was made in the shape shown in the sketch ; it was provided, as may be seen, with two other bearing blocks, fitted close to the
bends in the shaft. On account of its shape, a minor difficulty arose in connection with the erection of this shaft In the chassis. It could not be passed right through the two towing-hook brackets and in order to surmount this difficulty the . following plan was adopted :— The two inner bearings were slipped on to the shaft; one rivet was removed from the near-side towing-hook bracket, which allowed it to swing down about the only other rivet. The shaft was then threaded into the off-side bracket, and moved along that way until its motion could be reversed and its opposite end passed through the hole in the near-side bracket, when the latter was swung once more into its correct position. The remaining details of the apparatus will be clear to those who peruse the accompanying sketch. It will be observed that a short lever, secured to the near-side end of the shaft, provides for its being coupled to the compensating gear 'on the wagon by means of a b-in. red, upon which adjustment is provided by means of a wing-nut, Further means of adjustment is available in the turn-buckle which is inserted in the wire-rope connection between the brake-shaft and the trailer brake. The double attachment to the brake-shaft, as shown in the drawing, is necessary in order to allow freedom for turning.
A SIMPLE and ingenious form of tool
to facilitate the removal of shafts awd spindles which have become temporarily tight in their bearings is described by " S.R.H.," of London, W.9.
He simply takes two pieces of fiat bar, bends them crescent shape. and unites them near their ends, as shown in the sketch, by a pair of screws, which must be long enough and strong enough to serve as pull or push screws.
IN the case of some commercial
vehicles the brake-operating cam has moved through such a considerable angle by the time the brake linings are half worn that, even if it does not actually jam in the extreme position, further adjustment IS out of the question and new linings have to be fitted. This, as is pointed out by " H.S.," of Wrexham, can be avoided, and the brake linings
worn right down, if the expedient which is illustrated in one of the accompanying sketches be adopted. Liners of sheet steel, 1-16 in. thick, are fitted to the machined ends of the shoe against which the cam operates. These liners, as may be seen, are left long enough to enable them to be bent over at the top and bottom, thus preventing them from slipping out endways, whilst the flanges on the brake cam locate them laterally.
It is important to note that ordinary mild-steel sheet unhardened will serve this purpose, and that there is no need to take off the brake shoes when fitting the liners ; all that is necessary is to extend the shoes fully, pull the cam right over, and drive the liners in with a light hammer, subsequently bending them as shown.
SOME time ago reference was made by a contributor to this page to a trouble which he had experienced with a wirerope-operated brake. The rope to one brake shoe had broken and rendered both of them inoperative. He described how, by couplin„e each Ride of the rope to the corresponding frame member, he made sure that, in the event of a similar occurrence, he would still be able to operate one brake.
Another contributor, " A . W. ," of Dewsbury, in referring to this communication, expresses his belief in the principle that prevention is better than cure, and, beinghimself the driver of a vehicle equipped with brakes of this type, he set himself to discover how he might, in his own case, apply that principle.
After a little thought he came to the conclusion that breakage in these ropes resulted from the following circumstances :.—The lorry may be travelling with the brakes on, and the cables, therefore, already at high tension and considerably stretched. One of the lorry wheels strikes a pot-hole, and the shock momentarily drives the axle backwards in regard to the frame. There is no more "give" in the brake cables, and, consequently, one or other, or maybe both of them, if not actually broken at the time, is so far overstrained that a recurrence of the incident causes a breakage.. " A.W." prevents this by embodying a spring in the connection to each brake shoe. This spring is so stiff that its extension in the course of operation of the brake is negligible, but it will, nevertheless, expand sufficiently, in
• case of abnormal stresses, such as that to which reference has already been made, to relieve the cable to the r-quired extent.