Nikola Tesla U.S. Patent 514,169 - Reciprocating Engine Patent Wrapper Page 19

64 The Teren spring a prefertim to apply Air Cushion sto 2 Not sun. to be subjected to and it may be successfully used as a prime mover wherever a constant rate of oscillation or speed is required, provided the limits within which the forces tending to bring the moving system to a given position are proportionate to the displacements, are not materially exceeded. dunit Oct 30.93 The pressure of the air confined in the cylinder when the plunger J is in its central position will always be practically that of the surrounding atmosphere, for while the cylinder is so constructed as not to permit such sudden escape of air as to sensibly impair or modify the action of the air spring there will still be a slow leakage of air into or out of it around the pist an rod : according to the pressure therein, so that the pressure of the air on opposite sides of the plunger will always tend to remain at that of the outside atmosphere. As an instance of the uses to which this engine may 6 be applied I have shown its pist on rod connected with a pawl R the oscillation of which drives a train of wheels. These may constitute the train of a clock or of any other mechanism. Another application of the invention is to mo ve a conductor in a magnetic field for ge nerat ing electric currents, and in these and similar uses it is obvious that the characteristics of the engine render it specially adapted for use in small sizes or units. -9