Increased safety in use, and improved function, of ammunition items

Abstract

An electrically detonated fuse for a grenade is shown, used either as a b up system for the usual mechanical detonator, or independently as the sole arming and detonating means. The invention is considered more accurate and dependable than a mechanical system, which is aimed at the objective of reducing the amount of grenade duds, the dangerous phenomenon of still live grenades unexploded upon impact creating a hazardous situation for military and other personnel. The invention uses the ordinary action of the currently used inflated ribbon which is extended from the grenade while it is in flight, to generate an electromotive force signal via a piezoelectric crystal. An electrically activated detonator is installed next to the grenade's main charge, for blowing the device when the electrical detonator is switched on. A large surge of power is fed to the electrical detonator by the closing of an electrical impact fuse, when the grenade physically impacts a target. To store the necessary voltage for detonation a capacitor bank is employed, which store is charged by the said generated e.m.f. signal. The e.m.f. signal is generated through opposite polarization of a piezoelectric crystal, which the ribbon acts on in compression.

What is claimed is: 
     
       1. An electrical fuze for use in detonating a grenade which includes a main charge and a deploying ribbon loop for arming the grenade, said fuze comprising: means including a piezoelectric crystal for generating an electromotive force signal by the retarding action of said ribbon when deployed;   electrical circuit means for conditioning and storing said signal for use in detonating said grenade;   electrically operated detonation means for setting off the main charge, receiving a conditioned signal from said electrical circuit means;   means for closing a circuit upon a physical impact, said switch means positioned between said electrical circuit means and said detonation means.   
     
     
       2. A fuze as in claim 1 wherein said ribbon comprising a tape stiffener assembly and said means for generating a signal includes causing opposite polarization of a piezoelectric crystal which the ribbon acts on in compression. 
     
     
       3. A fuze as in claim 2 wherein said elecrical circuit means comprises a half-wave rectifying diode in series with a capacitance bank. 
     
     
       4. A fuze as in claim 3 wherein said switch means comprises an impact fuze. 
     
     
       5. A fuze as in claim 4 including an arming stem comprises a shear pin, which pin is sheared by the deployment of said tape stiffener assembly, permitting said compression of said piezoelectric crystal between a shoulder of such stem and the fuze housing.