Molded composite pyrogen igniter for rocket motors

Claim 1

A standardized lightweight pyrogen assembly for rocket motors comprising: a molded plastics elongated tube containing the pyrogen charge and adapted to be inserted in a rocket motor case for ignition of the rocket motor charge, said elongated tube being open at one end and having at least one passageway at the other end thereof for expelling ignition gases into the rocket motor, a molded plastics cap closing the open end of said elongated tube and serving as a closure for the rocket motor case, said elongated tube being provided with external spiral buttress threads on the open end and said cap being provided with internal spiral buttress threads for attachment to said elongated tube, said cap containing an ignition pellet cup and pellet retention means serving to close the open end of said cup for retaining an ignition charge therein, the other end of said cup being provided with a passageway to permit entrance of ignition gases to the interior of said cup, a safe-arm rotor disposed within said cap, said safe-arm rotor being provided with a bore therethrough, and rotatable from an armed position wherein said rotor alines the bore with the passageway in said cup and a safe position wherein a portion of said rotor blocks the passageway in said cup, a squib retained within said cap in a port that communicates with said rotor bore when said rotor is in said armed position, attachment means circumscribing the exterior surface of said closure cap, and said attachment means being secured to said cap so as to provide relative rotative movement therebetween and serving to sealingly attach the igniter assembly within the rocket motor casing.

Claim 13

A method of providing a gastight seal between two parts utilized to separate two areas of different gas pressures while maintaining relative rotative movement between the two parts comprising: providing a first part in the form of a rocket motor casing and adapted to withstand high gaseous pressures therein, providing at least one threaded opening in a wall of the first part, molding a plastics second part to serve as the closure for said first part, capturing an annular metal ring assembly within an annular groove formed on the exterior of the plastics closure during the molding thereof, providing a gastight seal between the captured annular metal ring and the molded plastics second part, providing external threads on the exterior of the annular ring assembly to engage the threaded opening in the first part, providing double O-ring seals in the abutting areas formed between the first and second part when they are threadedly connected, securing a rocket igniter within the rocket motor casing as an integral portion of the second part, and wherein the molded plastics and the metal ring assembly have inherent diverse thermal coefficients of expansion and during the molding process the metal ring will be captured within the plastics and during the normal post curing of the plastics the metal and plastics will separate sufficiently to permit relative rotative movement therebetween but will retain the gastight sealed relation between the rotative and stationary parts.

Claim 14

A method of providing a gastight seal between two parts utilized to separate two areas of different gas pressures while maintaining relative rotative movement between the two parts comprising: providing a first part in the form of a rocket motor casing and adapted to withstand high gaseous pressures therein, providing at least one threaded opening in a wall of the first part, molding a plastics second part to serve as the closure for said first part, capturing an annular metal ring assembly within an annular groove formed on the exterior of the plastics closure during the molding thereof, providing a gastight seal between the captured annular metal ring and the molded plastics second part, providing external threads on the exterior of the annular ring assembly to engage the threaded opening in the first part, providing double O-ring seals in the abutting areas formed between the first and second part when they are threadedly connected, securing a rocket igniter within the rocket motor casing as an integral portion of the second part, and wherein the molded plastics and the metal ring assembly have inherent diverse thermal coefficients of expansion and during the molding process the metal ring will be captured within the plastics and during the normal post curing of the plastics the metal and plastics will separate sufficiently to permit relative rotative movement therebetween but will retain the gastight sealed relation between the rotative and stationary parts.