A NEW GEARBOX

Evening Post, Volume CXXVI, Issue 50, 27 August 1938, Page 28

A NEW GEARBOX

EPICYCLIC AND AUTOMATIC

CONTINENTAL DEVELOPMENT

"One of the truest things which has ever been said is that you can only be sure of one thing about an invention, and that is that it will not work. Nevertheless there are exceptions to test the rule," states "The Motor." "One of these is the latest type of epicyclic gearbox now used in the Fleischel transmission. Transmissions Automatiques Fleischel, Luxembourg, have for many years been developing a fully automatic gear control. It is based on the fact that an engine publishes, so to speak, its need for a given gear by two things: speed and manifold pressure. Thus low speed and low manifold pressure indicate need for a lower gear. High speed and high manifold pressure, on the other hand, indicate need for a higher gear, assuming, of course, that the engine is unsupercharged. "If, therefore, a gear control is developed which is responsive by means of a capsule to manifold pressure and by a governor to speed, provided that these two are properly balanced in relation to each other, the engine will automatically select a higher or lower gear, as required. Whereas, however, with a normal gear change the throttle is closed during the actual period of gear shifting, this is not the case with an automatic transmission. "Very considerable difficulties have arisen in trying to obtain a gearbox which will stand up to changes of ratio on full throttle. It has been found that on existing types if a measure of slip is introduced to avoid shock, it soon becomes excessive and if no initial slip is provided then the gearbox wrecks itself. Moreover, the only type of gear which begins to fulfil the necessary demands is the epicyclic, which has the further disadvantage of being larger and heavier than the normal flash type. "To overcome all of these difficulties the Fleischel company has now designed its own gear. To keep it light and compact it has ingeniously coupled the epicyclic trains so that, they fulfil more than one purpose." A photograph with the notice shows the compact layout of the gear, and the spring loading which permits a smooth engagement under all conditions. The gear can be used with or without the automatic selection. A full set of drawings accompanies the article showing the different positions of the component parts for varying ratios. The journal expresses the opinion that the new gear may well prove a thoroughly useful adjunct to the automobile of the immediate future.