A device for preventing sparking in an electric ignition circuit when a lead becomesbroken, particularly adapted for use in aeroplanes

摘要

137,860. Bosch Akt.-Ges., R. Jan. 5, 1918, [Convention date]. Void [Published under Sect. 91 of the Act]. Gravity and inertia switches.-A device for preventing electric sparks at the point of rupture of the electric leads of the ignition circuit of a wrecked aeroplane at the moment when the lead is torn asunder by the impact, comprises an electric switch adapted to be operated automatically by the impact to short-circuit the primary winding of the ignition machine. In the construction shown, the device comprises a casing a in which is located a ball b held against a partition c by a spring-pressed rod d and surrounded by a flat spiral spring e bent into cylindrical shape as shown in Figs. 2 and 3. Through the partition extends a pin f abutting at one end against the ball and at the other end against an insulated spring g, the length of the pin being such that a contact i carried by the spring and an uninsulated contact k on the casing are normally held apart. When the aeroplane strikes the ground, the inertia of the ball causes this to move from between the pin and the rod, the spring cage giving way to allow of this movement; the contacts i, k move together and the primary winding l of the ignition machine is short-circuited. The device is re-set by drawing out the rod d, the spring cage returning the ball to its normal position.