# US 5,348,603 A · Composite/metal hybrid rocket motor case and methods for manufacturing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,603 A - Document ID: US5348603A - Status: Granted - Kind: A - Application number: 08/067,849 - Filed: 1993-05-27 - Granted: 1994-09-20 - Earliest claimed: 1992-06-25 - Assignees: Thiokol Corporation - Inventors: James A. Yorgason - Web page: https://patentgrep.com/patent/US5348603A ## CPC - B29C 43/3642: {Bags, bleeder sheets or cauls for isostatic pressing} - B29C 43/12: using bags surrounding the moulding material {or using membranes contacting the moulding material} - B29C 53/382: {using laminated sheets} - B29C 53/44: rotatable about the axis of the article - B29C 53/566: {for making tubular articles followed by compression} - B29C 63/16: applied by "rubber" bag or diaphragm - B29C 70/342: {using isostatic pressure} - B29C 70/78: Moulding material on one side only of the preformed part - F02K 9/34: Casings; Combustion chambers; Liners thereof - B29K 2105/0854: {in the form of a non-woven mat} - B29K 2105/0872: {Prepregs} - B29K 2105/258: {Tubular} - B29K 2705/02: Aluminium - B29L 2023/00: Tubular articles (B29L2024/00 takes precedence {; catheters B29L2031/7542}) - B29L 2031/3097: {Cosmonautical vehicles; Rockets} - F05D 2300/603: Composites; e.g. fibre-reinforced - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A composite/metal hybrid rocket motor case made by rolling sheets of continuous, unidirectional fiber reinforcement pre-impregnated with an uncured, thermoset or thermoplastic resin about the mandrel using a tube rolling machine to form a liner having discontinuous layers of fiber reinforcement. The liner is inserted into a metal shell configured with elongated slots. A mold is placed around the shell with a bladder placed within the liner. The bladder within the mold is then pressurized to force the liner against the metal shell while the contents of the mold are heated. As the liner cures, it bonds to the shell. Fins, launch lugs, domes and bulkheads may be attached to the metal shell by known attachment methods. ## Claims ### Claim 1 A process for manufacturing a case for a rocket motor, comprising the steps of: obtaining a sheet of uncured fiber reinforced plastic and a generally cylindrically shaped metal shell; configuring the sheet of uncured fiber reinforced plastic into a generally cylindrical shape; forming a plurality of apertures in the metal shell; inserting the cylindrically shaped sheet of plastic into the metal shell; attaching the cylindrically shaped sheet of plastic to the metal shell; inserting a cylindrically shaped layer of insulation inside the cylindrically shaped sheet of plastic; and curing the cylindrically shaped sheet of plastic such that it attaches to the cylindrically shaped layer of insulation. ### Claim 2 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said step of obtaining a sheet of uncured fiber reinforced plastic comprises obtaining a sheet of continuous, unidirectional fiber reinforcement which has been pre-impregnated with an uncured, thermoset resin. ### Claim 3 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said step of obtaining a sheet of uncured fiber reinforced plastic comprises obtaining a sheet of continuous, unidirectional fiber reinforcement which has been pre-impregnated with an uncured, thermoplastic resin. ### Claim 4 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said step of forming a plurality of apertures in the metal shell comprises forming the apertures such that they are elongated with their length oriented along the axis of the metal shell. ### Claim 5 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said curing step is preceded by introducing the cylindrically shaped sheet of plastic and the metal shell into a mold and said attaching step and said curing step comprise heating the plastic to a predetermined temperature and forcing the cylindrically shaped sheet of plastic against the metal shell while the plastic cures such that the plastic attaches to the metal shell. ### Claim 6 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said step of configuring the sheet of plastic into a cylindrical shape comprises rolling the sheet of plastic about a mandrel. ### Claim 7 (depends on 6) A process for manufacturing a case for a rocket motor as defined in claim 6, wherein said rolling step further comprises heating the sheet of plastic such that the viscosity of the plastic is decreased. ### Claim 8 (depends on 1) A process for manufacturing a case for a rocket motor as defined in claim 1, wherein said curing step is preceded by forcing the cylindrically shaped sheet of plastic against the metal shell and said attaching step and said curing step further comprise maintaining the cylindrically shaped sheet of plastic against the metal shell while curing the plastic such that the plastic attaches to the metal shell. ### Claim 9 (depends on 8) A process for manufacturing a case for a rocket motor as defined in claim 8, wherein said forcing step comprises forcing the cylindrically shaped sheet of plastic against the metal shell with an expandable bladder. ### Claim 10 A process for manufacturing a case for a rocket motor, comprising the steps of: obtaining a sheet of continuous, unidirectional fiber reinforcement which has been pre-impregnated with an uncured, thermoset resin; rolling the sheet of fiber reinforcement about a mandrel; repeating said obtaining and said rolling steps to form a generally cylindrically shaped liner reinforced with discontinuous fibers; obtaining a generally cylindrically shaped metal shell; forming a plurality of apertures in the metal shell; inserting the liner into the metal shell; forcing the liner against the metal shell; heating the liner to a predetermined temperature; and curing the liner while maintaining the liner forced against the metal shell and maintaining the liner at the predetermined temperature, thereby bonding the liner to the metal shell. ### Claim 11 (depends on 10) A process for manufacturing a case for a rocket motor as defined in claim 10, wherein said step of forming a plurality of apertures in the metal shell comprises forming the apertures in the shell such that they are substantially uniformly distributed and are elongated with their length oriented along the axis of the metal shell. ### Claim 12 (depends on 10) A process for manufacturing a case for a rocket motor as defined in claim 10, wherein said rolling step further comprises heating the sheet of plastic such that the viscosity of the plastic is decreased. ### Claim 13 (depends on 10) A process for manufacturing a case for a rocket motor as defined in claim 10, wherein said forcing step comprises inserting an expandable bladder within the liner and pressurizing the expandable bladder to a predetermined level such that the liner is forced against the metal shell. ### Claim 14 (depends on 13) A process for manufacturing a case for a rocket motor as defined in claim 13, wherein said heating step is preceded by introducing the liner and the metal shell into a mold and said curing step further comprises increasing the pressure within the expandable bladder. ### Claim 15 (depends on 11) A process for manufacturing a case for a rocket motor as defined in claim 11, wherein said rolling step is preceded by wrapping the mandrel with a release material. ### Claim 16 (depends on 15) A process for manufacturing a case for a rocket motor as defined in claim 15, wherein said wrapping step comprises wrapping the mandrel with a nylon film and dusting the release material with talc. ### Claim 17 (depends on 15) A process for manufacturing a case for a rocket motor as defined in claim 15, wherein said repeating step is followed by removing the release material from within the liner.