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 .
Response to Amendment
The amendment filed on 15 July 2025 has been entered. Claim(s) 21-29 remain pending in this application. Claim(s) 1-20 have been cancelled. Claim(s) 21-29 are new.
The amendment to the drawings has overcome the drawing objections set forth in the office action mailed 15 January 2025.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 21 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Smith (U.S. Patent No. 6,016,652), hereinafter Smith.
Regarding Independent Claim 21, Smith discloses a rocket engine (Figure 2) comprising:
a casing, 18, circumferentially extending around a longitudinal axis, Ax, to circumscribe a combustion chamber, 31, extending along the longitudinal axis (the combustion chamber, 31, extends along the longitudinal axis, Ax, and circumscribed by the casing, 18), the combustion chamber having an inlet, 29, and an outlet, 35, the combustion chamber defining a fuel-receiving volume (the volume of the combustion chamber, 31, that receives the fuel, 24, is a fuel receiving volume), the inlet fluidly connectable to a source, 12, of an oxidizer, 14, the outlet in fluid communication with an environment outside the combustion chamber for expelling combustion gases (Figure 2 – Column 9, Lines 9-11 – the outlet is connects the combustion chamber to the ambient environment to expel combustion gases);
a solid fuel, 24, located within the fuel-receiving volume (the volume of the combustion chamber, 31, receives the fuel, 24), the solid fuel configured to be exposed to the oxidizer injected in the combustion chamber via the inlet (Column 9, Lines 22-27 – the solid fuel is exposed to oxidizer injected through the inlet, 29), the solid fuel having a face exposed to the oxidizer (the top and bottom and radially inner face of the fuel, 24, is exposed to the oxidizer), an area of the face increasing as the solid fuel is being burned away (the radially inner face of the fuel is a cylindrical area and thus has an area that will increase as the radius from the central axis increases as the face regresses radially outward).
Claim(s) 21 and 27-28 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chen (U.S. Patent No. 9,458,796), hereinafter Chen.
Regarding Independent Claim 21, Chen discloses a rocket engine (Figure 2) comprising:
a casing, 3, circumferentially extending around a longitudinal axis (the rocket engine has a horizontal longitudinal axis when viewed as shown in Figure 2 about which the casing extends left to right) to circumscribe a combustion chamber, 11, extending along the longitudinal axis (the combustion chamber, 11, extends along the longitudinal axis and circumscribed by the casing, 2), the combustion chamber having an inlet, 5, and an outlet, 2, the combustion chamber defining a fuel-receiving volume (the volume of the combustion chamber, 11, that receives the middle fuel segment, 4, as shown in Figure 2 is the fuel receiving volume), the inlet fluidly connectable to a source of an oxidizer (Column 3, Lines 11-16 – the inlet, 5, injects oxidizer into the combustion chamber and thus is connected to a source of oxidizer), the outlet in fluid communication with an environment outside the combustion chamber for expelling combustion gases (Figure 2 – the outlet is connects the combustion chamber to the ambient environment to expel combustion gases);
a solid fuel (the middle fuel segment, 4, is a solid fuel) located within the fuel-receiving volume (the volume of the combustion chamber receives the fuel), the solid fuel configured to be exposed to the oxidizer injected in the combustion chamber via the inlet (the solid fuel is exposed to oxidizer injected through the inlet, 5), the solid fuel having a face exposed to the oxidizer (the right face and the radially innermost face of the fuel segment, 4, is exposed to the oxidizer), an area of the face increasing as the solid fuel is being burned away (the radially inner face of the fuel is a cylindrical area and thus has an area that will increase as the radius from the central axis increases as the face regresses radially outward).
Regarding Claim 27, Chen discloses the invention as claimed and discussed above. Chen further discloses the inlet includes at least one aperture defined through the casing and located axially between the fuel-receiving volume of the combustion chamber and the outlet of the combustion chamber relative to the longitudinal axis (Figures 2 and 3 - the inlet, 5, is series of apertures located through the casing, 3, that is between the fuel receiving volume and the outlet, 2).
Regarding Claim 28, Chen discloses the invention as claimed and discussed above. Chen further discloses the solid fuel burns along a regression direction parallel to the longitudinal axis (the right end face of the middle segment of fuel, 4, is a face that is perpendicular to the horizontal longitudinal axis, therefore the regression direction of the end face will be perpendicular to the face and parallel to the longitudinal axis).
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) 22 and 29 are rejected under 35 U.S.C. 103 as being unpatentable over Smith in view of Kobald (Non-Patent Literature – Viscosity and Regression Rate of Liquefying Hybrid Rocket Fuels), hereinafter Kobald.
Regarding Claims 22 and 29, Smith discloses the invention as claimed and discussed above. Smith further discloses the solid fuel includes a first solid fuel (Figure 14 – the fuel, 24, is configured as shown in Figure 14, with a first fuel being the radially outermost cylinder) and a second solid fuel (the second radially outermost cylinder surrounded by the first fuel is the second solid fuel), the first solid fuel extending around the second solid fuel (the first solid fuel is the radially outermost cylinder and thus surrounds the second solid fuel), the first solid fuel and the second solid fuel differing by one or more properties (Column 18, Lines 14-21 – the first and second solid fuel are different materials having different properties).
Smith does not explicitly disclose the property being a rheological property.
However, Kobald teaches hybrid rocket engines (Page 1245 – “Introduction”, Column 1, Line 1) wherein the composition of the fuel determines the viscosity of the liquid layer formed during combustion (Page 1245 – Abstract, Lines 5-6 – the different fuels have different viscosity levels) where the viscosity of the fuel effects the regression rate of the fuel (Page 1245 – Abstract, Line 9 and Page 1251, “Conclusions”, Column 1, Lines 3-9 – the regression rate of the fuel is effected by the viscosity of the fuel where the lower viscosity contributes to a higher regression rate).
Further it is noted that viscosity is recognized as a rheological property in Paragraph 00121 of the instant application.
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 Smith by making the differing property of the first and second solid fuels a rheological property/viscosity (Claim 29), as taught by Kobald, in order to better predict the regression rate of the fuels by their viscosities (Kobald – Page 1245 – Abstract, Lines 9-10).
Allowable Subject Matter
Claims 23-26 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
The prior art of record do not disclose “a mass flow rate of combustion gases generated by the solid fuel remains constant while a mass flow rate of the oxidizer in the combustion chamber is constant” along with the remaining structure of Claim 23.
The prior art of record do not disclose “the second solid fuel has a regression rate greater than the first solid fuel such that an axial offset is created between a first axial end face of the first solid fuel and a second axial end face of the second solid fuel” along with the remaining structure of Claim 24.
The prior art of record do not disclose “the solid fuel includes a central rod, a first tube around the central rod, and a second tube around the first tube” along with the remaining structure of Claim 25.
Claim 26 depends from Claim 25 and thus includes the allowable subject matter as indicated above.
Response to Arguments
Applicant’s arguments have been considered but are moot in view of the new grounds of rejection set forth herein.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/KYLE ROBERT THOMAS/Examiner, Art Unit 3741