Nikola Tesla U.S. Patent 511,916 - Electric Generator Patent Wrapper Page 11

18 Олек 2 In the construction of my engine above referred to I have followed and applied this principle, that is to say, I employ a cylinder and a piston which in any suitable manner I maintain in reciprocation by steam or gas under pressure. To the moving piston or to the cylinder, in case the latter reciproca te and the piston remain stationary, a spring is connected so as to be maintained in vibration thereby, and what ever may be the inertia of the pist on or of the moving system and the rigidity of the spring relatively to each other, provided, the practical limits within which the law holàs true that the forces which tend to bring the moving system to a given position are proportionate to the displacement are not exceeded, the impulses of the power impelled piston and the natural. vibrations of the spring will always correspond in direction and coincide in time. In the case of the engine referred to, the ports are so arranged that the movement of the pist on within the cylinder in either direction ceases when the force tending to impel it and the momentum which it has acquired are counterbalanced by the increasing pressure of the steam or compressed air in that end of the cylinder towards which it is moving, and as in its movement the piston has shut off at a given point, the pressure that impelled it and established the pressure that tends to return it, it is then impelled in the opposite direction, and this action is continued as long as the requisite pressure is ap