Pressure relief device for solid propellant motors subjected to high external temperatures

Claim 1

A rocket motor comprising a housing with a solid propellant mounted therein, said housing having a first groove extending into and around an internal surface which is void of said solid propellant at one of said housing, said housing having a second groove extending into and around an internal surface void of said propellant at the other end of said housing; closure means having a groove extending into and around the periphery of an external surface, said groove being in an adjacent position when installed to said first groove of said housing; heat responsive means mounted in said first groove of said housing and said groove of said closure means for securing the closure means to the housing; and a rocket motor nozzle having a groove extending into and around the periphery of an external surface, said groove being in an adjacent position when installed to said second groove of said housing; heat responsive means mounted in said second groove of said housing and said groove of said rocket nozzle for securing said rocket motor nozzle to said other end of said rocket motor housing, said heat responsive means having a melting point that is lower than the ignition point of said solid propellant so that when said housing is subjected to excessive external temperature, said heat responsive means will release said closure means and said rocket motor nozzle to prevent pressure build up in the motor housing, wherein said heat responsive means is a metal alloy and is contained in said groove of said closure means, in said groove of said rocket motor nozzle, and in said first groove and said second groove of said rocket motor housing with the grooves of the rocket motor housing, the rocket nozzle, and the closure means being filled with said metal alloy.