Reverse bulged forward acting scored rupture disc bulkhead structure for multi-stage rocket motor

Rupture disc bulkhead structure for use in a multi-stage rocket motor having a casing provided with a gaseous products discharge port and a plurality of propellant stages adapted to be ignited in successive order commencing with the stage in closest proximity to the discharge port, said bulkhead structure comprising:

• an essentially flat, non-apertured rupture disc presenting first and second disc faces and being adapted to be mounted in said casing between each adjacent pair of the propellant stages in full separating relationship thereto;
• and
• a multiple apertured backup member in flat engagement with the face of each disc opposed to the second face of the disc which is in direct contact with an adjacent propellant charge that has last been ignited, the backup member including a plurality of arm segments which at least partially define the apertures in the member,
• each of the discs being provided with a plurality of radially extending lines of weakness in the second face of a depth sufficient to cause rupture of that disc at a preselected pressure in a direction away from the backup member which is in supporting engagement with the disc, each line of weakness being aligned with one of the arm segments of the backup member such that the disc is able to withstand pressure thereagainst without rupture during ignition and burning of the last propellant stage to be ignited but to then rupture at a much lower pressure upon ignition of the propellant proximal to a corresponding backup member to allow free flow of gaseous propellant combustion products along a flow path extending through the bulkhead during burning of the latter propellant stage,
• each of the lines of weakness including a radially outer termination point, the discs being further provided with a groove formed in the second face and intersecting each termination point such that when the disc ruptures the disc is permitted to move substantially completely out of the flow path of the propellant combustion products by bending along the grooves.