After-firing safety device in a projectile with percussion fuze

摘要

An after-firing safety device in a projectile with percussion fuze includes a spiral spring set having at least three springs wound up in series with respectively opposite directions. The spring set, maintained under tension by a cage, starts to uncoil as soon as the cage slides off the spiral spring set on account of the acceleration of the projectile during firing. The time elapsing until a central aperture has been entirely vacated depends on the number of springs, the spring lengh, the spring tension, and the friction characteristic. The after-firing safety device is equally well suited for spinning projectiles as well as nonspinning projectiles.