Nikola Tesla U.S. Patent 514,169 - Reciprocating Engine Patent Wrapper Page 12

J J T 1 J JIJLJ The invention is based upon certain well known mechanical principles a statement of which will ass ist in a better understanding of the nature and purposes of the objects sought and results obtained. Heret ofore, where the pressure of st eam or any gas has been utilized and applied for the production of mechanical motion it has been customary to connect with the reciprocating or moving parts of the engine a fly-wheel. or some rotary system equivalent in its effect and possessing relatively great mechanical in etia, upon which dependence was mainly placed for the maintainance of constant speed. This, while securing in a, measure this object, renders impossible the attainment of the result at which I have arrived, and is attended by disadvantages which by my in vention are entirely obviated. On the other hand, in certain cases, where reciprocating engines or tools have been used without a rotating system of great inertia, no attempt, so far as I know, has been made to secure conditions which would necessarily yield such results as I have reached. It is a well known principle that if a spring possessing a sensible inertia be brought under tension, as by being stretched, and then freed it will perform vi-- brat ions which are isochronoue and, as to period, in the main dependent upon the rigidity of the spring, and its own inertia or that of the system of which it may form an 57