THERMALLY INITIATED MECHANICALLY FIRED DEVICE FOR PROVIDING PROTECTION AGAINST SLOW COOK-OFF

摘要

Slow cook-off protection for rocket motors is achieved through the use of a slow cook-off trigger mechanism in which a mechanical response is thermally initiated. A metallic housing contains and is thermally coupled to a bimetallic snap action disc spring. A firing pin is connected to the disc spring and telescopically guided by the housing toward an expolosive booster charge. The booster charge is coupled in a conventional manner to a linear shaped charge. The linear shaped charge is disposed adjacent to the rocket motor case in order to cut a stress riser in the casing when activated. The circular bimetallic spring is designed to snap between a first and second configuration to thereby drive the firing pin into the explosive booster charge at a predetermined temperature below the expected ignition temperature of the rocket propellant. After the trigger is activated and the linear chaped charge cuts a stress riser in a rocket casing, continued temperature rise results ignition of the rocket propellant. However, the stress riser in the rocket casing causes the rocketr casing to fail, thereby venting the propellant pressure through the split riser and thereby preventing the development of any substantial propulsive thrust.