This invention relates to springs of the description known as " elliptic," and consists in a novel mode of constructing and combining the upper and lower plates of the spring, whereby gr^er strength is obtained with a less werghl; of metal than is required in springs of the usual construction. In our engravings,* Fig. 1 represents this improved spring as adapted to railroad cars; Fig. 2 is a side elevation of the same, modified and applied to a locomotive truck; and Fig. 3 is a side view of a double elliptic spring, constructed upon the same improved plan, and designed for ordinary carriages. The ends of the upper leaf. A, of the spring, are bent around bolts, B, secured in jaws attached to the truck, C, of railroad cars, or to jointed bars, I J, on which is suspended the truck of the locomotive, arid the lower leases, E, which are made of different lengths, in the same manner as the common elliptic springs are made, of a more rounding curve, so as to leave the space between the center of the upper and longest leaf, and corresponding part of the leaf. A, wheH they are arranged below the same, with the ends of the upper longest leaf sprung in between, and arranged against, the rounded ends, B, of the leaf, A. The leaves, A E, are held in their places during their elastic movements over each other .by the usual clips, near the ends of the lower ones, and by right-angled jaws, F, between which they are placed, which jaws are secured to the journal boxes, G, arranged between the guides, D, secured to the truck of the car or locomotive. When this plan of spring is employed for ordinary carriages, the leaves, a h, are arranged in the relation together represented in Fig. 3, and are connected together by joint pins at c. It will be seen that the spring is supported at the center of the lower leaves, E, and receives the weight of the car or other object at or near the ends of the upper leaf, A. The tendency of the weight thus applied is to cause the plates, E, to be straightened, and this tendency exerts a tension in a nearly longitudinal direction on the plates, A a, so that while the plates, E 6, yield considerably in the direction of the pressure, the plates, A a, though suflBciently elastic, yield but slightly, and serve to give great strength, to the spring. Springs constructed on this plan have been in operation on the heaviest tenders on the Delaware and Lackawanna Railroad for a year past, and they are found to be capable of sustaining a far greater pressure with an equal degree of elasticity, and a saving of at least twenty per cent of steel, than the ordinary construction of springs. This excellent form of spring was patented December 29, 1857. Any further information can be obtained by addressing the inventor, George Douglass, Scranton, Luzerne county, Pa.
This article was originally published with the title "Douslass' Railroad Car Spring" in Scientific American 13, 41, 328 (June 1858)