DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claims 1-20 are pending in this application.
Claim Objections
Claim 15 is objected to because of the following informalities:
Regarding Claim 15 in Line 12 “the energetic fuel material” should be energetic material to provide consistent terminology in the claim.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Claims 1-6 and 15-20 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Claim 1 recites the limitation "the additive manufacturing process" in Line 29. There is insufficient antecedent basis for this limitation in the claim. It is unclear whether the additive manufacturing process is referring to the overall method being claimed or if it is referring to a different process, such as just the steps performed by the additive manufacturing device. For the purposes of this examination the limitation will be interpreted as the overall method.
Claims 2-6 depends from Claim 1 and are rejected accordingly.
Claim 3 recites the limitation "the cylindrical fuel grain" in Line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 5 recites the limitation "the additive manufacturing process" in Line 1. There is insufficient antecedent basis for this limitation in the claim. It is unclear whether the additive manufacturing process is referring to the overall method being claimed or if it is referring to a different process, such as just the steps performed by the additive manufacturing device. For the purposes of this examination the limitation will be interpreted as the overall method.
Claim 15 recites the limitation "the additive manufacturing process" in Line 12. There is insufficient antecedent basis for this limitation in the claim. It is unclear whether the additive manufacturing process is referring to the overall method being claimed or if it is referring to a different process, such as just the steps performed by the additive manufacturing device. For the purposes of this examination the limitation will be interpreted as the overall method.
Claims 16-20 depends from Claim 15 and are rejected accordingly.
Claim 17 recites the limitation "the additive manufacturing process" in Line 2. There is insufficient antecedent basis for this limitation in the claim. It is unclear whether the additive manufacturing process is referring to the overall method being claimed or if it is referring to a different process, such as just the steps performed by the additive manufacturing device. For the purposes of this examination the limitation will be interpreted as the overall method.
Regarding Claim 18, the limitation “the sensors provide telemetry to an external control system for real-time monitoring during storage and combustion” renders the claim indefinite. The limitation is directed towards a method of operating/using an apparatus where Claim 15, from which Claim 18 depends is directed towards a method of manufacturing. It is thus unclear how the method step of using applies to the method of manufacturing. For the purposes of this examination the limitation will be interpreted as the sensors being configured to provide telemetry to an external control system for real-time monitoring during storage and combustion.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Fuller (U.S. Pre-grant Publication 2013/0042596), hereinafter Fuller, in view of Summers (U.S. Patent No. 10,287,218), hereinafter Summers, and Jones (U.S. Patent No. 10,309,346), hereinafter Jones.
Regarding Independent Claim 1, Fuller discloses a method of making a fuel grain for use in a rocket engine (Figures 1 and 3-5 - Abstract), the method comprising:
a first material, 418, suitable as a hybrid rocket propellant, a second energetic material, 412, and a third ignitable material, 414;
feeding the material into an additive manufacturing device (Figures 1 and 3-5 – the material is provided to a device, 406 and 424, which make up an additive manufacturing device):
operating the additive manufacturing device to fabricate a fuel grain, 402, comprising a plurality of stacked layers of solidified material (Figure 5 – the material is provided in layers to form the fuel grain), each stacked layer comprising concentric circular structures of different diameter fused together to form a central opening (Figures 4 and 5 – the grain is formed by layers of concentric circular structures, as shown in Figure 4, to form a grain with a central port, 438):
aligning the stacked layers such that the central openings form a combustion unit extending axially through the fuel grain and bounded by a combustion surface (Figures 3 and 4 – Paragraph 0004– the central opening/port of the grain is the location where combustion occurs and thus the port and the surface of the layers that form the port make up a combustion unit that extends through the grain and bounded by the internal surface of the grain):
configuring the fuel grain to include heterogeneous materials comprising unfilled fuel materials and filled fuel materials to enhance thrust performance (it is noted that Applicant’s Paragraph 0063 describes filled thermoplastics as thermoplastics/fuel materials containing at least one additive – Figure 4 - Paragraphs 0051, 0053 and 0081 – the different fuel sections shown in Figure 4 have different fuel materials/compositions in order to enhance/provide a desired thrust performance; the fuel grain includes fuel materials along and mixtures of fuel materials and additives, i.e. filled and unfilled fuel materials): and
wherein the additive manufacturing process permits integration of heterogeneous energetic compositions not achievable by conventional cast or cured propellant fabrication methods (Figure 4 - Paragraphs 0051, 0053 and 0081 – the different fuel sections shown in Figure 4 have different fuel materials/compositions and thus meets the limitation).
Fuller does not disclose compounding the first material, the second energetic material, and the third ignitable material according to a predetermined mixture ratio to form a compounded raw material; feeding the compounded raw material into an additive manufacturing device; and the fuel grain comprising thermoplastics.
However, Summers teaches a method of making a fuel grain for use in a rocket engine (Figures 1 and 2) comprising compounding multiple materials according to a predetermined mixture ratio to form a compounded raw material (Figure 1 – Column 4, Lines 2-6 – the multiple materials are provided in the predetermined/appropriate amounts to the mixer, 16, to form a compounded raw material); feeding the compounded raw material into an additive manufacturing device (Figures 1 and 2 – the raw material is feed to the structure, 50, that make up an additive manufacturing device).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Fuller by including compounding the first material, the second energetic material, and the third ignitable material according to a predetermined mixture ratio to form a compounded raw material; feeding the compounded raw material into an additive manufacturing device, as taught by Summers, in order to provide a safer process that minimizes the need to handle mixed propellant material (Summers – Column 3, Lines 60-61).
Fuller in view of Summers do not disclose the fuel material comprises thermoplastics.
However, Jones teaches the use of a Acrynotrile Butadiene Styrene (ABS) thermoplastic fuel or a fuel formulation consisting of a blend of ABS thermoplastic and aluminum powder in an additive manufacturing process (Abstract and Column 9, Lines 9-14 – the fuel grain is formed of unfilled thermoplastics/ABS and filled thermoplastics/ABS).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the invention of Fuller in view of Summers by making the fuel material comprises thermoplastics, as taught by Jones, resulting in the unfilled fuel materials and filled fuel materials being unfilled thermoplastics and filled thermoplastics since it has been held that the selection of a known material (in the present case thermoplastic/ABS) based on its suitability for its intended use (providing a fuel material) would have been an obvious extension of prior art teachings. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), MPEP 2144.07.
Regarding Claim 2, Fuller in view of Summers and Jones disclose the invention as claimed and discussed above. Fuller further discloses the combustion unit comprises a polygonal shape (Figure 4 – the port/combustion unit, 438, shown is a star/polygonal shape).
Regarding Claim 3, Fuller in view of Summers and Jones disclose the invention as claimed and discussed above. Fuller in view of Summers and Jones, as discussed so far, do not disclose embedding thermally insulating materials around the cylindrical fuel grain to regulate combustion temperature.
However, Jones further teaches the use of thermally insulating materials around the fuel grain to regulate combustion temperature (Figure 5 – Column 12, Lines 60-67 – the fuel grain is wrapped with an insulating material to prevent thermal damage/regulate combustion temperature).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Fuller in view of Summers and Jones by embedding thermally insulating materials around the cylindrical fuel grain to regulate combustion temperature, as taught by Jones, in order to prevent thermal damage (Jones – Column 12, Lines 60-67).
Regarding Claim 4, Fuller in view of Summers and Jones disclose the invention as claimed and discussed above. Fuller in view of Summers and Jones, as discussed so far, do not disclose the heterogeneous materials further comprise nanocomposites including aluminum or other metallic additives.
However, Jones further teaches the use of nanocomposites including aluminum (Column 9, Lines 9-14 – the fuel material used includes composite material of ABS and nano scale aluminum).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Fuller in view of Summers and Jones by making the heterogeneous materials further comprise nanocomposites including aluminum, as taught by Jones, since it has been held that the selection of a known material (in the present case nanocomposites that include aluminum) based on its suitability for its intended use (providing a fuel material/heterogenous fuel material) would have been an obvious extension of prior art teachings. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), MPEP 2144.07.
Claim(s) 5 is rejected under 35 U.S.C. 103 as being unpatentable over Fuller in view of Summers and Jones as applied to claim 1 above, and further in view of Jones (U.S. Patent No. 10,286,599), hereinafter Jones ‘599.
Regarding Claim 5, Fuller in view of Summers and Jones disclose the invention as claimed and discussed above. Fuller in view of Summers and Jones do not disclose the additive manufacturing process is performed under an inert atmosphere to reduce moisture and degradation.
However, Jones ‘599 teaches a method of additive manufacturing a rocket fuel grain (Title) where the additive manufacturing process is performed under an inert atmosphere to reduce moisture and degradation (Column 15, Lines 4-38 – an inert gas covers the printing area during fabrication and thus would perform the function of reducing moisture and degradation).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Fuller in view of Summers and Jones by including the additive manufacturing process is performed under an inert atmosphere to reduce moisture and degradation, as taught by Jones ‘599, in order to provide an additional safety measure (Jones ‘599 – Column 15, Lines 20-25).
Claim(s) 6 is rejected under 35 U.S.C. 103 as being unpatentable over Fuller in view of Summers and Jones as applied to claim 1 above, and further in view of Danforth (U.S. Pre-grant Publication 2017 /0253536), hereinafter Danforth.
Regarding Claim 6, Fuller in view of Summers and Jones disclose the invention as claimed and discussed above. Fuller in view of Summers and Jones do not disclose the heterogeneous propellants are electrically activated solid propellants.
However, Danforth teaches an additive manufacturing method that uses electrically activated solid propellants (Abstract).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the invention Fuller in view of Summers and Jones by making the heterogeneous propellants are electrically activated solid propellants since it has been held that the selection of a known material (in the present case electrically activated solid propellants) based on its suitability for its intended use (providing a fuel material/heterogenous fuel material that is additively manufactured) would have been an obvious extension of prior art teachings. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), MPEP 2144.07.
Claim(s) 7-9, 11-12 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Summers in view of Fuller, Jones and Kuntz (U.S. Patent No. 3,246,053), hereinafter Kuntz.
Regarding Independent Claim 7 and Claim 9, Summers discloses a method for producing a multi-component rocket fuel grain with tailored combustion properties (Figures 1 and 2), the method comprising:
continuously feeding a first fuel material, 20, a second oxidizer material, 22, and a third binder, 24, material into a robotic mixer, 16;
dynamically adjusting the mixture ratio of the first, second, and third materials (Column 4, Lines 29-32 – the flow rates of the materials is controlled, i.e. dynamically adjusted) in response to real-time monitoring of viscosity and composition to form a modified fuel composition (Column 4, Lines 2-6 and 29-32 and Column 5, Lines 31-44 – the method controls the amounts of the materials to the appropriate/predetermined amounts, i.e. according to monitored amounts/composition, and based on measurements that include viscosity to achieve a fuel composition/mixture);
extruding the modified fuel composition in a plurality of concentric layers to create a solidified fuel grain (Column 6, Lines 35-47 – the grain, 12, is produced by the buildup of the fuel material in layers that are concentric to each other);
aligning the plurality of concentric layers to form a central combustion port extending axially through the fuel grain (Column 6, Lines 35-47 – the grain has a central opening formed by the plurality of layers that are built up);
curing the solidified fuel grain (Column 7, Lines 38-44 – the fuel grain is cured).
Summers does not disclose each layer including alternating materials to produce zones with distinct combustion characteristics; embedding structural elements within the layers to control oxidizer flow and combustion surface area; curing the solidified fuel grain under controlled inert-gas conditions to achieve desired mechanical and thermal properties; configuring the fuel grain with an outer thermally insulating layer to reduce heat loss during combustion.
However, Fuller teaches a method for producing a multi-component rocket fuel grain (Figures 1 and 3-5 - Abstract) with alternating materials to produce zones with distinct combustion characteristics (Figure 4 – Paragraph 0089 – the grain is made with different/alternating materials to provide different combustion characteristics).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers by making each layer including alternating materials to produce zones with distinct combustion characteristics, as taught Fuller, in order to allow the grain to provide specific pressures, i.e. thrust, throughout operation (Fuller – Paragraph 0056).
Summers in view of Fuller do not disclose embedding structural elements within the layers to control oxidizer flow and combustion surface area; curing the solidified fuel grain under controlled inert-gas conditions to achieve desired mechanical and thermal properties; configuring the fuel grain with an outer thermally insulating layer to reduce heat loss during combustion.
However, Jones teaches a method for additively manufacturing a rocket fuel grain (Title - Abstract) where the method includes embedding structural elements within layers to control oxidizer flow and combustion surface area (Column 11, Lines 14-60 – the layers used to form the grain includes elements, such as ribs (Claim 9), that extend into the bore/port to effect/induce vortex/control the flow of gases, i.e. oxidizer, through the port, and increase/control the combustion surface area).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers in view of Fuller by making the method include embedding structural elements within the layers to control oxidizer flow and combustion surface area, as taught by Jones, in order to provide the desired surface area and oxidizer/gas flow for combustion (Jones – Column 11, Lines 14-60).
Summers in view of Fuller and Jones, as discussed so far, do not disclose curing the solidified fuel grain under controlled inert-gas conditions to achieve desired mechanical and thermal properties; configuring the fuel grain with an outer thermally insulating layer to reduce heat loss during combustion.
However, Jones further teaches the use of an outer thermally insulating layer to reduce heat loss during combustion (Figure 5 – Column 12, Lines 60-67 – the fuel grain is wrapped with an insulating material to prevent thermal damage/regulate combustion temperature).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers in view of Fuller and Jones by configuring the fuel grain with an outer thermally insulating layer to reduce heat loss during combustion, as taught by Jones, in order to prevent thermal damage (Jones – Column 12, Lines 60-67).
Summers in view of Fuller and Jones do not disclose curing the solidified fuel grain under controlled inert-gas conditions to achieve desired mechanical and thermal properties.
However, Kuntz teaches a method of manufacturing a solid fuel grain (Title) where the solid fuel grain is cured under controlled inert-gas conditions (Column 3, Lines 58-60 – the curing of the grain occurs under inert gas conditions to displace atmospheric gases) to achieve desired mechanical and thermal properties (Column 1, Lines 16-37 – the curing process results in the grain having a desired tensile strength/mechanical property and thermal shrinkage/thermal properties).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers in view of Fuller and Jones by making the method include curing the solidified fuel grain under controlled inert-gas conditions to achieve desired mechanical and thermal properties, as taught by Kuntz, in order to provide a method that does not produce exothermic reactions which would constitute an explosive hazard (Kuntz – Column 5, Lines 63-69).
Regarding Claim 8, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers in view of Fuller, Jones and Kuntz, as discussed so far, do not disclose the alternating material zones comprise regions of higher regression rate and regions of slower regression rate.
However, Fuller further teaches alternating material zones comprise regions of higher regression rate and regions of slower regression rate (Paragraph 0082 – the different regions comprises different regression rates, i.e. zones of higher regression rate and zones of lower regression rate).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the invention of Summers in view of Fuller, Jones and Kuntz by making the alternating material zones comprise regions of higher regression rate and regions of slower regression rate, as taught by Fuller, for the same reasons as discussed above for Claim 7.
Regarding Claim 11, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers further discloses the oxidizer material comprises a perchlorate based oxidizer that is ammonium perchlorate (Column 4, Lines 7-15).
Regarding Claim 12, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers in view of Fuller, Jones and Kuntz, as discussed so far, do not disclose the binder material comprises a thermoplastic polymer selected from ABS, polyethylene, or polyurethane.
However, Jones teaches the use of a Acrynotrile Butadiene Styrene (ABS) thermoplastic polymer as a binder (Abstract and Column 9, Lines 9-14 – the fuel grain is formed of unfilled thermoplastics/ABS and filled thermoplastics/ABS).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the invention of Summers in view of Fuller, Jones and Kuntz by making the binder material comprises a thermoplastic polymer that is ABS, as taught by Jones, since it has been held that the selection of a known material (in the present case thermoplastic/ABS) based on its suitability for its intended use (providing a binder material) would have been an obvious extension of prior art teachings. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), MPEP 2144.07.
Regarding Claim 14, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers in view of Fuller, Jones and Kuntz, as discussed so far, do not explicitly disclose zones with distinct combustion properties are tailored to provide staged thrust output during rocket flight.
However, Fuller further teaches zones comprise regions of higher regression rate and regions of slower regression rate (Paragraph 0082 – the different regions comprises different regression rates, i.e. zones of higher regression rate and zones of lower regression rate) and as evidenced by Column 3, Lines 33-38 of Jones the regression rate of the fuel effects the mass flow rate and thus the thrust provided by that fuel. Thus the slower regression rate fuel would provide a different thrust output than the higher regression rate fuel thereby providing staged thrust output during rocket flight.
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have further modified the invention of Summers in view of Fuller, Jones and Kuntz by making the zones with distinct combustion properties are tailored to provide staged thrust output during rocket flight, as taught by Fuller, for the same reasons as discussed above for Claim 7.
Claim(s) 10 is rejected under 35 U.S.C. 103 as being unpatentable over Summers in view of Fuller, Jones and Kuntz as applied to claim 7 above, and further in view of Buller (U.S. Pre-grant Publication 2017/0341183), hereinafter Buller.
Regarding Claim 10, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers further discloses dynamic adjustment of mixture ratio is based on feedback from in situ sensors viscosity (Column 4, Lines 2-6, 29-32, 49-58 and column 5, Lines 31-44 – a feedback system that monitors viscosity is used to provide control to the amount of respective components of the grain).
Summers in view of Fuller, Jones and Kuntz do not disclose monitoring particle distribution.
However, Buller teaches an additive manufacturing process usable for aerospace/missile system (Title – Paragraph 0130) that uses a feedback system that monitors particle distribution and adjusts the manufacturing process (Paragraph 0059).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers in view of Fuller, Jones and Kuntz such that the method includes monitoring particle distribution, as taught by Buller, in order to result in better outcome in the process (Buller – Paragraph 0006).
Claim(s) 13 is rejected under 35 U.S.C. 103 as being unpatentable over Summers in view of Fuller, Jones and Kuntz as applied to claim 7 above, and further in view of Harvey (U.S. Patent No. 4,177,227), hereinafter Harvey.
Regarding Claim 13, Summers in view of Fuller, Jones and Kuntz disclose the invention as claimed and discussed above. Summers in view of Fuller, Jones and Kuntz do not disclose curing is performed at controlled temperature and pressure conditions to achieve improved mechanical strength.
However, Harvey teaches a method of fabricating a fuel grain (Title) that include curing is performed at controlled temperature and pressure conditions to achieve improved mechanical strength (Column 20, Lines 28-35 – the grain is cured at a controlled temperature and pressure to reach desired/improved mechanical properties).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Summers in view of Fuller, Jones and Kuntz such that curing is performed at controlled temperature and pressure conditions to achieve improved mechanical strength, as taught by Harvey, in order to achieve desirable characteristics of the grain (Harvey – Column 5, Lines 43-50).
Claim(s) 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over Danforth (U.S. Pre-grant Publication 2017 /0253536), hereinafter Danforth, in view of Danforth (U.S. Patent No. 10,023,505), hereinafter Danforth ‘505, Tracy (U.S. Patent No. 8,659,422), hereinafter Tracy, and Hunter (U.S. Patent No. 10,492,686), hereinafter Hunter.
Regarding Independent Claim 15 and Claim 16, Danforth discloses a method of fabricating an electrically ignitable fuel grain for a rocket engine (Abstract – Figure 1), the method comprising:
providing an additive manufacturing device, 34, configured to extrude both energetic (Paragraph 0030 – the fuel and oxidizer are energetic materials extruded by the device) and inert materials (Paragraph 0030 – the binder material includes polyethylene oxide, which is an inert material);
operating the additive manufacturing device to fabricate a plurality of stacked layers (Paragraph 0029 – the process forms the grain layer by layer that are stacked on each other) forming a cylindrical fuel grain (Figure 1 and 3 – the grain, 12/212, is cylindrical);
embedding within the stacked layers a series of sections comprising electrodes during fabrication (Paragraph 0003 – the electrodes, 15 and 16, are embedded in the sections of the layers when they are additively manufactured at the same time as the grain);
wherein the electrodes are configured to electrically ignite the fuel grain (Paragraph 0030 – the electrodes are used to ignite the fuel grain); and
wherein the additive manufacturing process co-fabricates the energetic fuel material and the electrodes, as an integrated unit (Paragraph 0003 – the electrodes, 15 and 16, are additively manufactured at the same time as the grain as an integrated unit).
Danforth does not disclose having a central combustion port; annular sections; embedding sensors during fabrication; wherein the sensors are configured to monitor at least one of stabilizer depletion, internal offgassing, internal swelling, and pressure buildup; and wherein the additive manufacturing process co-fabricates the sensors.
However, Danforth ‘505 teaches a method for manufacturing a propellant grain (Title) where stacked layers form a cylindrical fuel grain having a central combustion port (Figure 3 – the layers of the grain produces has a central combustion port, 210).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Danforth by making the stacked layers form a cylindrical fuel grain having a central combustion port, as taught by Danforth ‘505, resulting in annular sections forming the grain in order to provide a combustion cavity for the combustion of the propellant (Danforth ‘505 – Column 6, Lines 60-67).
Danforth in view of Danforth ‘505 do not disclose embedding sensors during fabrication; wherein the sensors are configured to monitor at least one of stabilizer depletion, internal offgassing, internal swelling, and pressure buildup; and wherein the additive manufacturing process co-fabricates the sensors.
However, Tracy teaches a rocket propellant grain (Title – Figure 2) with sensors, 207 and 209, embedded during the fabrication process (Column 2, Line 64- Column 3, Line 2– the sensors are embedded in the grain during the fabrication process), wherein the sensors are configured to monitor internal swelling (Column 5, Lines 7-16 – sensors used are capable of sensing strain which is the change of shape, i.e. the swelling of the grain).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Danforth in view of Danforth ‘505 by including embedding sensors during fabrication; wherein the sensors are configured to monitor internal swelling, as taught by Tracy, in order to provide health and usage monitoring of the grain (Tracy – Column 2, Lines 22-25).
Danforth in view of Danforth ‘505 and Tracy do not disclose wherein the additive manufacturing process co-fabricates the sensors.
However, Hunter teaches an additive manufacturing process usable for rockets (Column 110, Lines 4-11 and Column 122, Lines 23-36) where sensors are co-fabricated with the component it is embedded in (Column 110, Lines 4-29 – the sensor is fabricated simultaneously with the overall component).
Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the invention of Danforth in view of Danforth ‘505 and Tracy by making the additive manufacturing process co-fabricate the sensors simultaneously with the fuel grain material (Claim 16), as taught by Hunter, in order to allow for accurate placement of the sensor within the overall assembly (Hunter – Column 109, Lines 48-54).
Regarding Claim 17, Danforth in view of Danforth ‘505, Tracy and Hunter disclose the invention as claimed and discussed above. Danforth further discloses the electrodes are fabricated using conductive filaments during the additive manufacturing process (Paragraph 0015 – the electrodes are formed by conductive fibers/filaments).
Regarding Claim 18, Danforth in view of Danforth ‘505, Tracy and Hunter disclose the invention as claimed and discussed above. Tracy further discloses the sensors are configured to provide telemetry to an external control system for real-time monitoring during storage and combustion (Column 5, Lines 17-21 and Column 6, Lines 21-32 – the sensors are able to provide information regarding the grain, i.e. telemetry, wirelessly, and therefore to an outside control system and allow real-time monitoring during storage and combustion). Thus the combination of Danforth in view of Danforth ‘505, Tracy and Hunter, as discussed above would result in the limitations of Claim 18.
Regarding Claim 19, Danforth in view of Danforth ‘505, Tracy and Hunter disclose the invention as claimed and discussed above. Danforth further discloses the fuel grain further comprises insulating layers fabricated in situ by the additive manufacturing device (Paragraph 0029 and 0042 – the casing, 18, surrounding the propellant is additively manufactured as the grain is made where the casing include insulating material separating conductive material from the propellant).
Regarding Claim 20, Danforth in view of Danforth ‘505, Tracy and Hunter disclose the invention as claimed and discussed above. Danforth further discloses the electrodes are configured to permit selective ignition of different sections of the fuel grain (Paragraph 0048 – the propellant between adjacent electrodes is ignited when power is applied to the two adjacent electrodes, thus the electrodes are able to be operated such that they selectively ignite different sections of the fuel grain).
Conclusion
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/KYLE ROBERT THOMAS/Examiner, Art Unit 3741
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