The technical field of the invention is that of impact fuses for projectiles. It is known to produce impact fuses that include a piezoelectric generator for generating an electrical voltage upon the fuse impacting a target.
Conventionally, piezoelectric generators comprise one or several piezoelectric ceramics stacked on one another. Such a generator is placed on a bracket that is integral with the fuse body and the generator serves as an anvil.
In other respects, the fuse comprises a piston for mechanically contacting (exerting stress on) the generator upon impact. The FR-1595412 patent describes such a known impact fuse. The electrical voltage obtained from the generator is used to initiate an electrical primer.
One of the problems with the known fuses is that, under some impact conditions, the electrical voltage generated may be insufficient to ensure the initiation of the primer.
This is due to the fact that the shock received by the generator is too brief (the force on the generator is insufficient).
In other respects, initiation of the primer due to relatively low energy levels and/or detonation of the casing must be avoided.
Thus, contradictory conditions are present. On the one hand, a deformation of the generator sufficient to ensure a nominal electrical voltage allowing the initiation of the primer is needed. On the other hand, preventing any deformation of the generator at a reduced shock level is likewise needed.
The FR-2669416 patent describes a priming device that comprises a piezoelectric generator integral with the fuse body and is actuated by a hammer upon impact. At that time, the hammer is projected toward the piezoelectric generator as a result of the shockwave leaving from the cap. With such a concept, the shock received by the generator is all the same too brief. In other respects, the WO-85/03345 reference describes a percussion fuse comprising a piezoelectric generator and a means for enhancing safety. This means involves combining a self induction coil and a spark gap. Thus the firing is only caused when the rising edge of the received pulse exceeds a given amplitude.
The purpose of the fuse of this reference is different than that of the disclosed invention because the purpose of the reference is directed to a mechanical link for ensuring a high and brief pulse of the piston on the generator.