Safing and arming device

In a weapon subject to a sequence of acceleration followed by spin, including a detonator and an explosive charge, the improvement comprising a barrier located between said detonator and explosive charge to normally form an obstruction to prevent accidental detonation of said explosive charge by said detonator, said barrier having a center-of-gravity offset radially outwardly of the axis of spin sufficiently so as to be completely removable laterally as an obstruction between said detonator and explosive charge, mechanical locking means devoid of a source of electrical power for its operation for normally locking said barrier in place to provide said obstruction, said mechanical locking means including a spirally wound ribbon wrapped around said barrier, restraining means normally engaging an outer surface of said spirally wound ribbon to prevent premature unwinding of said ribbon, said restraining means being responsive to said acceleration to disengage said ribbon and permit unwinding thereof as a consequence of said spin, said mechanical locking means also comprising locking elements restrained by the inner leaves of said spirally wound ribbon and normally locking said barrier in place, said locking elements being responsive to a predetermined number of spins to unlock and remove said barrier laterally and provide an unobstructed path between said detonator and explosive charge.