TORSION BAR SUSPENSION

Evening Star, Issue 25700, 25 January 1946, Page 2

TORSION BAR SUSPENSION

~ I T^t 1 *'•••••' ■ ■ SIMPLE SPRINGING SYSTEM PROVED DURING WAR Before the war, torsion bar suspension had proved its worth in the European motor-racing World, some. of the world’s fastest racing ears being equipped with this form of suspension. During the war, this simple system Of springing was used successfully _ih certain Army tanks aiid mobile Units, and nOw there are strong possibilities that torsion bars will be found in some of the European and American 1946 , oars. As, no doubt, many motorists have no knowledge as to the exact meaning of torsion bar. suspension, a few, details as to this form of body suspension will not be amiss. In its best-known form, it is represented by. the use of highgrade spring steel in the form of a shaft,; like an axle shaft. Usually , one end is attached to the wheel by iueatis of suitable linkage, while the other end is firmly attached to the chassis. One shaft or bar is provided for each wheol. ' . That a solid bar of- steel cab provide a flexible spring will surprise many, motor owners, The torsion Bar is made of the best alloy spring steel—the quality is carefully controlled right from the steel mill, , and watolled just as carefully while in the process _of manufacture. Experts have developed some special processing methods which are responsible fof the outstanding performance of the. torsion bar. , j The first of these is the mecliaiucal operation of ,f pre-settirig ”■ the .bar. * This-is a blatter of overloading it to specifications, so that it takes on a permanent set, in the dll ection of loading on the vehicle. The spring action of a torsion bar is. in the. form of a twist along its entire length. Since one end is held rigidly while the. other is twistfd by the. linkage, as the wheel moves up and down. The pre-set puts an initial and permanent twist in the bar.. Tt is then sho't-preened. thereby minimising fatigue failure. The combination of . pre-settiiig and shot\pfee'ning produces oars that can take unlimited punishment. ■ _ , According to a handbook issiied by the U.S.A. Society of Automotive Engineers, the effectiveness of a spring is measured. in terms of energy in pound-inches it can absorb for a poiitid of spring weight. On this basis, the, absorption capacity of the leaf spritig With properly stepped leaves (found on most passenger cars) Ganges from 300 to’ 400, the helical round Wire spring (knee-action type) 500 to 1,000, and torsion-bar spring .1,000 to 1,500. These figures, plus simplicity in design,- with less mechanical and los§ weight, are features likely to .gain torsion-bar suspension special consideration by car manufacturers in the Sotdistant future.^