1920.] 
Reviews and Abstracts. 
61 
These two equations form the basis of the investigation. When applied 
to the ordinary* type of spring, with square-ended leaves of equal thickness 
throughout and with equal overhangs, they show that the reactions (W n, &c.) 
and stresses are very unequal for the various leaves. In such springs the 
short leaf is always stressed more than any other, and is the weakest link 
in the chain, so that such a spring with 12 leaves is only as good as one of 
7f leaves equally stressed throughout. Further, although the overhangs 
can be calculated to equalize the reactions, the stresses are still unequal, 
and little improvement in actual strength results. If, however, the ends 
of the leaves are tapered to the correct shape with mathematical exactitude 
the reactions and stresses can be equalized in every leaf, and the safe load 
of the spring correspondingly increased. 
Although the spring commonly referred to in text-books in which each 
leaf is tapered (in width) to a point for the exact length of each equal over¬ 
hang has this quality, and should be an ideal spring, other modifying 
circumstances, “ which will be duly discussed, ,? | prevent such springs 
fulfilling this promise, and they are not used in practice. 
Further tapering the points of the leaves in any way in the plane of 
the width only has no practical effect on the reactions, stresses, J or strength 
of springs, and is only of use from the aesthetic point of view. 
The “ double-tapered ” leaf, shown in the figure above, is the most 
important type of end, and is the subject of several patents granted to 
the authors. In springs of this construction the leaves are highly stressed 
at the points and at the buckles, but are not so highly stressed at their 
centres. A slot of mathematical proportions is therefore punched out of 
* “ Ordinary ” applies to America. 
f The authors tantalizingly forget to duly discuss this point.— S. H. J. 
f The previous conclusion says that such tapering in the “ text-book ” spring equalizes 
the reactions and stresses.— S. H. J. 
