NEW DESIGNS

Ashburton Guardian, Volume 58, Issue 301, 1 October 1938, Page 5

NEW DESIGNS

BRAKE IMPROVEMENT. MEETING GREATER SPEEDS. The greatly increased speeds possible in popular models during the last rew years have focussed a good deal of attention on brake design. The aim is to increase braking efficiency, so that even more effective stopping power will be available than with present designs, good as they are. One of the problems of the brake designer is to distribute the braking effort equally on the two shoes in each shoes are generally hinged together at one end and expanded at the other. As the expander is usually at the top, the direction of rotation of the drum tends to wrap the leading shoe into the drum but push the. training shoe away, so that nine times out of ten, the leading shoe does most of the work. Th.e problem is to make the trailing shoe carry its fair share. One of the simplest and most logical methods of achieving this appears to have been developed by a leading manufacturer of hydraulic brakes in England. The idea is to pivot each shoe separately, the leading one at the _bottom, as at present', and tlie trailing one at the top. Separate operating cylinders are used for each shoe, that for the front one at the top and the cylinder for the training one at the bottom. Thus, each shots is then subjected to the self-wrapping action imposed by the rotation of the drum, and each one hears its fair share of the load. An alternative scheme is to mount each shoe on square instead of round pivots, with the slots in tlie shoes instead of holes. These are formed into each shoe in such a fashion that application of tli-a brakes makes each shoe move outwards i-nto closer contact with the drum at the pivoted ends, instead of leaving the whole of this force to the ends operated by the hydraulic cylinder as at present. FOR NEW DRIVERS. SIMPLE PRECAUTION. There is a simple little thing connected with the driving of a, car which new owners often fail to realise, until a few dented mudguards have driven the lesson home. This is that the rear wheels do not follow the front ones when a car is being cornered, but take an inside path across that of the front wheels. This means that if the car is cut across the bows of another vehicle, there is an excellent chance of dragging the rear near side mudguard across the offside front guard of that other car. Most people are rather careful in this respect- when both cars are moving, but the greatest danger arises when the new owner is attempting to- park his car in front of a stationary vehicle. 1 The principle should be remembered, also, however, when taking a fairly abrupt cujrve. If cut too fine with 1 the near side front wheel, the rear one is almost certain to hit the kerb fairly hard and a badly bruised tyre may he the result.

PLATING ALUMINIUM. A PROBLEM SOLVED. For some 30 years, experts have been searching for a practical, fast and inexpensive method of plating aluminium with nickel, copper or chromium, hut all efforts failed on account of the insistent film of oxygen which forms on the surface of aluminium. This disability, it it- reported, has at last been overcome by, AA r . J. Travers, an American chemist, who has been searching for a solution of the problem for nearly 20 years. The outcome of his efforts is a patent that covers a process that will enable aluminium articles to he treated in volume in a normal manner by ordinary plating establishments. The Travers process subjects the article to be plated by treatment that creates upon it an anodic oxide film which leaves the aluminium surface hard and resistant. The article is then placed in an alkaline bath which modifies the anodic oxide film and prepares the surface for plating by tlie ordinary -process, using the same element and the same solutions. The result is a bond between the aluminium and the plate, which is stated to -be an entirely new one and a. discovery that promises application in a tremendously wide industrial field. Needless to say, the Travers plating process is likely to play an important part in the automobile industry, for by it, aluminium pistons, etc., can be plated with chromium, thus providing this hard-working component with a surface that will almost defy wear. Tests of long duration, conducted by automobile laboratories, have proved that the expansion and contraction of the plated piston under working conditions does not adversely affect the plating, nor does extreme cold or heat. At present, the world is using some 167,000 tons of aluminium annually—a volume that probably will be greatly, increased by the adoption of this new plating process.