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 submitted 12/01/2025 has been entered. Claims 1--20 remain pending.
Response to Arguments
Applicant's arguments filed 12/01/2025 have been fully considered but they are not persuasive. The amendments to the claims have changed the scope of the claims necessitating new and modified grounds of rejection. Please see new and modified grounds of rejection below.
The Applicant argues that the prior art does not teach all limitations of the claims since the claims now require a droop which disrupts “the smooth, S-shaped curve of the camber line 60 near the leading edge 40” and that the camber line shown in Figure 17 of Mikic is smooth.
The Examiner respectfully disagrees. The Applicant has disclosed any special definition for “droop” nor described any limits on what may or may not be considered a “droop”. Merriam-Webster defines droop as “to hang or incline downward” which is clearly shown in Figure 17 of Mikic where, notably, the distance from the chord line 170 to lower surface 130 increases to a maximum proximate the leading edge.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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, 6, and 8-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 11407510 to Mikic in view of US 10746025 to Yoshida.
(a) Regarding claim 1:
(i) Mikic discloses a rotor (airfoil 100, see abstract) comprising a length that extends from a first end to a tip (span of airfoil 100, Fig 20), the first end configured to be adjacent to a hub of a rotor system (rotor hub 550, Fig 20), the rotor including a cross- section that changes from a first cross-section at the first end to a second cross-section at the tip (Col 8 Lns 56-66), wherein the rotor includes:
a leading edge (150, Fig 17), a trailing edge (160, Fig 17) opposite the leading edge (Fig 17), an upper surface (120, Fig 17) and a lower surface (130, Fig 17) opposite the upper surface (Fig 17),
wherein the first cross-section has a profile defined by:
a chord length (length 171 or L of chord line 170, Fig 17) extending from the leading edge of the rotor to the trailing edge of the rotor (Fig 17), and
a maximum thickness (maximum thickness 175, Fig 17) at a midpoint of the chord length (maximum thickness 175 located at a chordwise location 176 of 0.50 L, where L is the chord length; Fig 17; Col 9 Lns 29-33), and
wherein the maximum thickness is defined by a diameter of a largest circle extending between the upper surface of the rotor and the lower surface of the rotor (must exist as defined in the claim), and
a camber line (172 at the first cross section, Fig 17);
wherein the second cross-section has a profile including a camber line (172 at the second cross section, Fig 17), and
wherein the camber line of the profile of the second cross-section is different from the camber line of the profile of the first cross-section (Col 8 Lns 56-66), and
wherein the lower surface includes a droop adjacent the leading edge of the rotor (the distance from the chord line 170 to lower surface 130 increases to a maximum proximate the leading edge), the droop reducing the positive camber of the first cross section adjacent the leading edge of the rotor (Fig 17).
(ii) Mikic does not explicitly disclose:
wherein the camber line is an S-shape such that the camber line has a positive camber from the leading edge of the rotor to the midpoint of the chord length and has a negative camber from the midpoint of the chord length to the trailing edge of the rotor.
(iii) Yoshida is also in the field of rotor blades (see abstract) and teaches a rotor comprising:
leading and trailing edges (43 and 44, respectively, Fig 3),
a chord length (length of a straight line connecting leading and trailing edges, Fig 3),
a camber line (line along mid points between pressure surface 46p and suction surface 46n from leading edge 43 to trailing edge 44, Fig 3), and
wherein the camber line is an S-shape such that the camber line has a positive camber from the leading edge of the rotor to a midpoint of the chord length and a negative camber from a midpoint of the chord length to the trailing edge of the rotor (radius R1 equal to radius R2, Col 5 Lns 56-59, and profile is of substantially constant thickness from leading to trailing edge so camber line must be substantially parallel and equal in length to lines of pressure and suction sides 46p/46n of which the point where the leading edge side meets the trailing edge side is boundary line b disclosed by Yoshida as being located equal to halfway along those lines, Col 8 Lns 60-65; Fig 3).
(iv) 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 camber line of the first cross-section as disclosed by Mikic to be s-shaped as taught by Yoshida for the purpose of reducing flow from the pressure side of the blade to the suction side of the blade thereby increasing efficiency (Col 1 Lns 54-56).
(b) Regarding claim 2:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic further discloses wherein, at the first end of the rotor, a radius of the leading edge is at least 0.5% of the chord length (Col 8 Lns 12-18).
(c) Regarding claim 3:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic further discloses wherein, at the first end of the rotor, a radius of the leading edge is a continuous curve without discontinuity (must be for a radiused edge; reasonably disclosed in Fig 17).
(d) Regarding claim 4:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic further discloses wherein, at the first end of the rotor, a radius of the trailing edge is at least 0.5% of the chord length (Col 8 Lns 26-30).
(e) Regarding claim 6:
(i) Mikic as modified by Yoshida teaches the rotor of claim 5.
(ii) The claim “wherein, at the first end of the rotor, the rounded trailing edge of the profile and the camber line having the S-shape of the profile are configured to, in use of the rotor at a first operating point, increase a length of flow attachment to the rotor compared to a length of flow attachment to a rotor having an airfoil with an elliptical profile operating at the first operating point, and wherein the first operating point includes a positive pitch angle” is a functional limitation. As the prior art teaches all structural limitations of the claims, the rounded trailing edge of the profile and s-shape of the profile in the proposed combination is capable of performing the claimed function.
(f) Regarding claim 8:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic further discloses wherein, at the first end of the rotor, a radius of the leading edge and a radius of the trailing edge are equal (any value common to both ranges disclosed by Mikic for leading and trailing edges, e.g. 0.05 L; Col 8 Lns 12-18 and Col 8 Lns 26-30).
(g) Regarding claim 9:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Yoshida further teaches wherein, at the first end of the rotor, the camber line of the profile of the first cross-section passes through the midpoint of the chord length (Yoshida teaches wherein curves of R1 and R2 are equal wherein each curve extends from a leading or trailing edge to a mid point of the chord, see rejections above, therefore the camber line inflection point between the two curves must be located at the mid point of the chord).
(h) Regarding claim 10:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Yoshida further teaches wherein, at the first end of the rotor, the positive camber is a same magnitude as the negative camber (curves of R1 and R2 are equal wherein each curve extends from a leading or trailing edge to a mid point of the chord, see rejections above; therefore, the magnitudes of the positive and negative cambers must be equal).
(i) Regarding claim 11:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Yoshida further teaches wherein, at the first end of the rotor, the positive camber is a smaller magnitude than a magnitude of the negative camber (R1 may be greater than R2 leading to a smaller distance between the chord and the camber line at the leading edge curve than at the trailing edge curve, Col 8 Ln 66 – Col 9 Ln 2; Fig 3).
(j) Regarding claim 12:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic as modified by Yoshida further teach wherein, at the first end of the rotor, the first cross-section is taken perpendicularly to the leading edge of the airfoil (Mikic: Fig 17; Yoshida: Fig 3).
(k) Regarding claim 13:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Yoshida further wherein, at the first end of the rotor, a half of the profile taken from the midpoint of the chord length extending toward the leading edge is an inverted, mirror image of a second half of the profile taken from the midpoint of the chord length extending toward the trailing edge (the airfoil cross section is substantially constant in thickness and curves of R1 and R2 are equal wherein each curve extends from a leading or trailing edge to a mid point of the chord in a direction opposite to the other, see rejections above; therefore the profile of the first half must be an inverted mirror image of the second half).
Claim(s) 1 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 11407510 to Mikic in view of US 10443607 to Brown.
(a) Regarding claim 1:
(i) Mikic discloses a rotor (airfoil 100, see abstract) comprising a length that extends from a first end to a tip (span of airfoil 100, Fig 20), the first end configured to be adjacent to a hub of a rotor system (rotor hub 550, Fig 20), the rotor including a cross- section that changes from a first cross-section at the first end to a second cross-section at the tip (Col 8 Lns 56-66), wherein the rotor includes:
a leading edge (150, Fig 17), a trailing edge (160, Fig 17) opposite the leading edge (Fig 17), an upper surface (120, Fig 17) and a lower surface (130, Fig 17) opposite the upper surface (Fig 17),
wherein the first cross-section has a profile defined by:
a chord length (length 171 or L of chord line 170, Fig 17) extending from the leading edge of the rotor to the trailing edge of the rotor (Fig 17), and
a maximum thickness (maximum thickness 175, Fig 17) at a midpoint of the chord length (maximum thickness 175 located at a chordwise location 176 of 0.50 L, where L is the chord length; Fig 17; Col 9 Lns 29-33), and
wherein the maximum thickness is defined by a diameter of a largest circle extending between the upper surface of the rotor and the lower surface of the rotor (must exist as defined in the claim), and
a camber line (172 at the first cross section, Fig 17);
wherein the second cross-section has a profile including a camber line (172 at the second cross section, Fig 17), and
wherein the camber line of the profile of the second cross-section is different from the camber line of the profile of the first cross-section (Col 8 Lns 56-66), and
wherein the lower surface includes a droop adjacent the leading edge of the rotor (the distance from the chord line 170 to lower surface 130 increases to a maximum proximate the leading edge), the droop reducing the positive camber of the first cross section adjacent the leading edge of the rotor (Fig 17).
(ii) Mikic does not explicitly disclose:
wherein the camber line is an S-shape such that the camber line has a positive camber from the leading edge of the rotor to the midpoint of the chord length and has a negative camber from the midpoint of the chord length to the trailing edge of the rotor.
(iii) Brown is also in the field of blades (see title) and teaches an airfoil (blade 332, Fig 7) comprising a camber line (356, Fig 7) which has a negative camber from a midpoint of a chord length (negative camber may begin at a chordwise location of 30 times a radius of the trailing edge from the trailing edge, Col 7 Lns 51-53; Mikic discloses trailing edge radii that, when multiplied by a value within the range taught by Brown, would locate the beginning of the negative camber at the midpoint of the chord length, Mikic: Col 8 Lns 26-30) to a trailing edge of the airfoil (354, Fig 7).
(iv) 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 camber line as disclosed by Mikic to have a negative camber at the trailing edge of the airfoil as taught by Brown for the purpose of achieving a desired exit flow direction and reducing thickness (Col 2 Lns 48-60) and biasing the profile toward the suction surface (Col 3 Lns 1-7).
(v) The Examiner notes that the leading edge half of the camber line disclosed by Mikic has a positive camber and in the proposed combination with the teachings of Brown would have a negative camber on a trailing edge half of the camber line with a point of inflection therebetween, i.e. S-shaped.
(b) Regarding claim 15:
(i) Mikic as modified by Brown teaches the rotor of claim 1.
(ii) Brown further teaches wherein the second cross-section is a standard airfoil (wherein the trailing edge side negative camber is located only at a radially inner or intermediate portion of the rotor and the second cross-section is located at the tip; Col 6 Lns 24-28).
Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 11407510 to Mikic in view of US 10746025 to Yoshida as evidenced by US 12199305 to Villanueva.
(a) Regarding claim 5:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic as modified by Yoshida do not teach wherein, at the first end of the rotor, the maximum thickness is 25%-30% of the chord length of the rotor.
(iii) The Office is taking official notice that it is well known in the art for rotors, at the first end of the rotor, to have a maximum thickness that is 25%-30% of the chord length of the rotor as evidence by Villanueva (25%-30%, Col 7 Lns 11-16).
Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 11407510 to Mikic in view of US 10746025 to Yoshida, as applied to claim 1 above, and further in view of US 12305611 to Petsche.
(a) Regarding claim 7:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Mikic as modified by Yoshida does not teach wherein, at the first end of the rotor, the maximum thickness is 70%-90% of the chord length of the rotor.
(iii) Petsche is also in the field of rotors (see title) and teaches a rotor wherein, at a first end of the rotor, the maximum thickness is 75% of the chord length of the rotor (Col 4 Lns 27-33).
(iv) 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 rotor as disclosed by Mikic with the above aforementioned maximum thickness as taught by Petsche for the purpose of providing a rotor with optimized design and lift-to-drag ratios (Col 4 Lns 27-29).
Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 10822076 to Hunter in view of US 11407510 to Mikic in further view of US 10746025 to Yoshida.
(a) Regarding claims 14:
(i) Mikic as modified by Yoshida teaches the rotor of claim 1.
(ii) Hunter discloses a dual-rotor rotorcraft (see title) having a first rotor and a second rotor (upper and lower rotor assemblies 28 and 32, Fig 1), wherein the first rotor and the second rotor rotate in opposite directions (Col 2 Lns 34-35).
(iv) 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 first and second rotors as disclosed by Hunter to comprise the rotor of claim 1 as taught by Mikic as modified by Yoshida for the purpose of reducing noise (Mikic: Col 1 Lns 26-34) and/or reducing flow from the pressure side of the blade to the suction side of the blade thereby increasing efficiency (Yoshida: Col 1 Lns 54-56).
Claim(s) 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 10822076 to Hunter in view of US 11407510 to Mikic in further view of US 10443607 to Brown.
(a) Regarding claim 16:
(i) Hunter discloses a dual-rotor rotorcraft (see title) having a first rotor blade and a second rotor blade (blades of upper and lower rotor assemblies 28 and 32, Fig 1) each having an airfoil (see abstract) comprising a camber line (inherent to all airfoils) and configured to operate in both a forward and reverse flow condition (absent Applicant discloses a special definition of “operate”, all airfoils may be operated in both forward and reverse flow conditions).
(ii) Hunter does not disclose:
an airfoil body having a leading edge, a trailing edge opposite the leading edge, an upper surface and a lower surface opposite the upper surface,
wherein the airfoil body, in cross-section, has a profile defined by:
a chord length extending from the leading edge of the airfoil to the trailing edge of the airfoil,
a maximum thickness at a midpoint of the chord length,
wherein the maximum thickness is defined by a diameter of a largest circle extending between the upper surface of the airfoil and the lower surface of the airfoil, and
a camber line, wherein the camber line has a positive camber from the leading edge of the airfoil to the midpoint of the chord length and has a negative camber from the midpoint of the chord length to the trailing edge of the airfoil.
(iii) Mikic discloses an airfoil for a rotor blade (see abstract), the airfoil comprising:
an airfoil body (airfoil 100) having a leading edge (150, Fig 17), a trailing edge (160, Fig 17) opposite the leading edge (Fig 17), an upper surface (120, Fig 17) and a lower surface (130, Fig 17) opposite the upper surface (Fig 17),
wherein the airfoil body, in cross-section, has a profile defined by:
a chord length (length 171 or L of chord line 170, Fig 17) extending from the leading edge of the airfoil to the trailing edge of the airfoil (Fig 17),
a maximum thickness (maximum thickness 175, Fig 17) at a midpoint of the chord length (maximum thickness 175 located at a chordwise location 176 of 0.50 L, where L is the chord length; Fig 17; Col 9 Lns 29-33),
wherein the maximum thickness is defined by a diameter of a largest circle extending between the upper surface of the airfoil and the lower surface of the airfoil (must exist as defined in the claim), and
a camber line (camber line 172, Fig 17), wherein the camber line has a positive camber from the leading edge of the airfoil to the midpoint of the chord length (Fig 17), and
wherein the lower surface includes a droop adjacent the leading edge of the rotor (the distance from the chord line 170 to lower surface 130 increases to a maximum proximate the leading edge), the droop reducing the positive camber of the first cross section adjacent the leading edge of the rotor (Fig 17).
(iv) 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 airfoil as disclosed by Hunter with the above aforementioned airfoil as taught by Mikic for the purpose of reducing noise (Col 1 Lns 26-34).
(v) Hunter as modified by Mikic does not explicitly teach:
wherein the camber line has a negative camber from the midpoint of the chord length to the trailing edge of the airfoil.
(iii) Brown is also in the field of blades (see title) and teaches an airfoil (blade 332, Fig 7) comprising a camber line (356, Fig 7) which has a negative camber from a midpoint of a chord length (negative camber may begin at a chordwise location of 30 times a radius of the trailing edge from the trailing edge, Col 7 Lns 51-53; Mikic discloses trailing edge radii that, when multiplied by a value within the range taught by Brown, would locate the beginning of the negative camber at the midpoint of the chord length, Mikic: Col 8 Lns 26-30) to a trailing edge of the airfoil (354, Fig 7).
(iv) 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 camber line as taught by Hunter as modified by Mikic to have a negative camber at the trailing edge of the airfoil as taught by Brown for the purpose of achieving a desired exit flow direction and reducing thickness (Col 2 Lns 48-60) and biasing the profile toward the suction surface (Col 3 Lns 1-7).
(b) Regarding claim 17:
(i) Hunter as modified by Mikic as further modified by Brown teaches the airfoil of claim 16.
(ii) Mikic further teaches wherein a radius of the leading edge is a continuous curve without discontinuity (must be for a radiused edge; reasonably disclosed in Fig 17), and wherein a radius of the trailing edge is a continuous curve without discontinuity (must be for a radiused edge; Col 8 Lns 26-30).
(c) Regarding claim 18:
(i) Hunter as modified by Mikic as further modified by Brown teaches the airfoil of claim 16.
(ii) Mikic further teaches wherein a radius of the leading edge is at least 0.5% of the chord length (Col 8 Lns 12-18), and wherein a radius of the trailing edge is at least 0.5% of the chord length (Col 8 Lns 26-30).
Claim(s) 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 10822076 to Hunter in view of US 11407510 to Mikic in further view of US 10443607 to Brown as evidenced by US 12199305 to Villanueva.
(a) Regarding claim 19:
(i) Hunter as modified by Mikic as further modified by Brown teaches the airfoil of claim 16.
(ii) Hunter as modified by Mikic as further modified by Brown does not teach wherein, at the first end of the rotor, the maximum thickness is 25%-30% of the chord length of the rotor.
(iii) The Office is taking official notice that it is well known in the art for rotors, at the first end of the rotor, to have a maximum thickness that is 25%-30% of the chord length of the rotor as evidence by Villanueva (25%-30%, Col 7 Lns 11-16).
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 10822076 to Hunter in view of US 11407510 to Mikic in further view of US 10443607 to Brown, as applied to claim 17 above, and further in view of US 12305611 to Petsche.
(a) Regarding claim 20:
(i) Hunter as modified by Mikic as further modified by Brown teaches the airfoil of claim 17.
(ii) Hunter as modified by Mikic as further modified by Brown does not teach wherein the maximum thickness is 70%-90% of the chord length of the airfoil.
(iii) Petsche is also in the field of rotors (see title) and teaches an airfoil wherein the maximum thickness is 75% of the chord length of the airfoil (Col 4 Lns 27-33).
(iv) 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 airfoil as taught by Hunter as modified by Mikic as further modified by Brown with the above aforementioned maximum thickness as taught by Petsche for the purpose of providing a rotor with optimized design and lift-to-drag ratios (Col 4 Lns 27-29).
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Justin A Pruitt whose telephone number is (571)272-8383. The examiner can normally be reached T-F 8:30am - 6:30pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Nathaniel Wiehe can be reached at (571) 272-8648. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JUSTIN A PRUITT/Examiner, Art Unit 3745
/NATHANIEL E WIEHE/Supervisory Patent Examiner, Art Unit 3745