Patent ID: 8925463
Filing Date: 2015-01-06
Classification: F42B

Abstract:
1. A cartridge munition comprising, in combination: (a) a cartridge case having a base and an upper portion forming a propulsion chamber; (b) a projectile having a base inserted into the upper portion of the cartridge case and mechanically connected thereto; (c) a pyrotechnic propellant charge disposed in the propulsion chamber of the cartridge case whose propulsive gases exert a force on the base of the projectile when they burn causing the projectile to be driven out of the cartridge case; and (d) a pyrotechnic igniter or primer disposed in the base of the cartridge case for igniting the propellant charge; the improvement wherein said cartridge munition includes a pressure release device for venting propulsive gases from the propulsion chamber of the cartridge case if an elevated ambient temperature, lower than the ignition temperature of the igniter and the propulsive charge, presents a risk of self-ignition, said pressure release device including a retaining ring made of shape-memory material, which surrounds the igniter and retains the igniter in the base of the cartridge case, and at least one ring-shaped nut adapted to fix said retaining ring in said base of the cartridge case; wherein said retaining ring increases its diameter upon reaching said elevated temperature, thereby enabling separation of the igniter from the base of the cartridge case leaving an opening in the base of the cartridge for ventilation of propulsive gases.