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 10/29/2025 has been entered. Claims 4, 5 were canceled. Claims 1-3, 6-20 remain pending in the application. Applicant’s amendments to the Claims have overcome each and every objection and 112(b) rejections.
Response to Arguments
Applicant’s arguments, with respect to the drawing objection have been fully considered and are persuasive. The drawing objections on claims 9, 13 and 18 have been withdrawn.
Applicant’s arguments, see Applicant’s remarks filed on 10/29/2025 with respect to the rejection(s) of claim(s) 1-3, 6-20 under 35 U.S.C. 102 have been fully considered and are persuasive. While the cited prior art, Ensslin (U.S. Pre-Grant Publication No. 2021/0253231), teaches a rotary damper, i.e., a device that dampens vibration in rotary direction, in a form of a fluid viscous damper (linear gas spring that damps relative pivotal (rotary) motion; paragraph [0041]), the Examiner acknowledges Ensslin does not sufficiently teach a rotary fluid viscous damper, which utilizes rotary motion of viscous fluid for dampening. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Aubry (U.S. Patent No. 4,768,630) teaching a rotary fluid viscous damper applicable for aircraft flight control.
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) 1-3, 5-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ensslin (U.S. Pre-Grant Publication No. 2021/0253231) in view of Aubry (4,768,630).
As per claim 1, Ensslin discloses a rotor assembly comprising a first rotor, a second rotor and a damper system, the first and second rotors (a plurality of stacked propellers 110; paragraph [0018]; figure 8) being arranged to be rotated about a common axis for thrust generation by a drive system (paragraph [0026]) and where the first rotor is rotatable about the common axis (102) relative to the second rotor between a stowed configuration of the rotor assembly in which a rotor blade of the first rotor and a rotor blade of the second rotor are substantially angularly aligned (as shown; figure 1) and a deployed configuration in which the rotor blade of the first rotor and the rotor blade of the second rotor are angularly misaligned (as shown; figure 2) and where the damper system is arranged to generate a damper force opposing the relative rotation between the first and second rotors in at least one of the direction towards the stowed configuration and the direction towards the deployed configuration (coupling assembly 120 (damper system) has return spring 192, in the form of linear gas spring providing a damping functionality to damp a relative pivotal (rotary) motion of the first propeller 110 and the second propeller 110; paragraph [0041]), wherein the damper is a rotary damper (damping a relative pivotal (rotary) motion; paragraph [0041]) that uses viscous fluid (gas, i.e., fluid inherently having some viscosity; paragraph [0041]). However, Ensslin does not explicitly teach a rotary fluid viscous damper as it relies on a linear gas spring.
Aubry is related prior art in that it deals with a damper that provides damping in the rotary direction in the field of aircraft flight control (column 3, lines 31-33). Aubry teaches a rotary fluid viscous damper that works by viscous fluid filled in a chamber engaging rotary motion of a plurality of rotor blades within the damper (see abstract). Aubry teaches this arrangement also provides twisting stiffness, i.e., rotary spring-like behavior, as well as damping function of the rotary motion (abstract; column 6, lines 20-22). Aubry also teaches this arrangement is very simple and very economical to produce and maintain during operation (column 7, lines 37-40). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date, to modify Ensslin’s return spring and damper assembly to incorporate Aubry’s rotary fluid viscous damper since Aubry’s rotary damper is capable of providing twisting stiffness (spring behavior in the rotary direction) and damping (Aubry) while also being very simple and very economical to produce and maintain during operation (column 7, lines 37-40).
As per claim 2, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where torque from the drive system is delivered to the first rotor through the damper system (coupling assembly 120 operates to transmit the input torque to the second propeller or the first propeller; paragraph [0031]).
As per claim 3, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where the damper system is arranged such that the damper force increases proportionally with increasing relative rotation rate between the first and second rotors (linear gas spring including a main cylinder that contains a gas and a plunger that compresses the gas, i.e., capable of providing damper force proportional to the speed of the rotation; paragraph [0041]). Also Aubry’s fluid damper system is arranged such that the damper force increases substantially proportionally with increasing relative rotation rate between the first and second rotors (inherent damping behavior of fluid damper).
As per claim 6, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses that the relative rotation occurring towards the deployed configuration is at least in part passively driven (coupling assembly 120 configured to transition between the stowed configuration and the deployed configuration based upon the rotational velocity and inertia of the coupling arms, i.e., passive; paragraph [0026], [0042]).
As per claim 7, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses that the relative rotation occurring towards the stowed configuration is at least in part passively driven (transitioning from the deployed configuration to the stowed configuration by creasing the rotational velocity, i.e., passive; paragraph [0159]).
As per claim 8, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses wherein the first rotor is biased with a force to rotate it towards the stowed configuration of the rotor assembly (return spring 192 configured to bias coupling assembly 120 toward the stowed configuration; paragraph [0041]).
As per claim 9, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 8, and further discloses a biasing means that biases the first rotor with the force, and wherein the biasing means is combined in a unit with the damper system (linear gas spring (biasing means) having a main cylinder that contains a gas and a plunger; paragraph [0041]). Aubry also teaches a biasing means that biases the first rotor with the force, and wherein the biasing means is combined in a unit with the damper system (twisting elastic return movement; column 6, lines 20-22)
As per claim 10, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where to the extent that the rotor assembly remains in the deployed configuration whilst the first rotor is being driven by the drive system, the deployed configuration is maintained at least in part passively (coupling guide member 162 maintaining coupling assembly 120 in the deployed configuration; paragraph [0035]).
As per claim 11, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where to the extent that the rotor assembly remains in the stowed configuration, the stowed configuration is maintained at least in part passively (when the coupling assembly rotational velocity is at or below a threshold, the coupling assembly 120 is in the stowed configuration; paragraph [0026]).
As per claim 12, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where the second rotor is rigidly mounted to a drive shaft of the drive system, thereby rotating with the drive shaft (lower propeller 54 is fixed coupled to input shaft 52; paragraph [0050]).
As per claim 13, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where the first rotor is mounted to the drive shaft via a bearing (upper propellers 110 are connected via bearing 62; paragraph [0050]; figure 8).
As per claim 14, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where a separation between the blades of the first and second rotor assemblies is less than substantially 100% of a mean aerodynamic blade chord length of the blades (the distance (separation) between the propeller hubs 116 are shown to be much less than the chord length of the blades 118; figure 8).
As per claim 15, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where each of the first and second rotors has exactly two blades (each propeller 110 includes two propeller blades 118; paragraph [0020]).
As per claim 16, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where the rotor assembly is arranged for use in generating thrust to power a flying vehicle (propeller generating a high amount of vertical thrust; paragraph [0017]).
As per claim 17, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where the rotor assembly is a non-tilting thrust rotor assembly (propeller generating a high amount of vertical thrust; paragraph [0017]).
As per claim 18, Ensslin, in view of Aubry, discloses a rotor assembly according to claim 1, and further discloses where when in the stowed configuration the rotor blade of the first rotor and the rotor blade of the second rotor are arranged such that their longitudinal axes are aligned with an incoming air flow direction during forward flight (as shown, in the stowed configuration, the propeller blades are aligned in the direction along the longitudinal direction of the aircraft fuselage, i.e., also aligns with the incoming air; figure 10).
As per claim 19, Ensslin, in view of Aubry, discloses a flying vehicle comprising the rotor assembly according to claim 1 (as shown; figures 9-10).
As per claim 20, Ensslin, in view of Aubry, discloses a method of controlling reconfiguration of a rotor assembly, the rotor assembly comprising a first rotor and a second rotor (a plurality of stacked propellers 110; paragraph [0018]; figure 8), the first and second rotors being arranged to be rotated about a common axis for thrust generation by a drive system (paragraph [0026]) and where the first rotor is rotatable about the common axis (102; figure 8) relative to the second rotor between a stowed configuration of the rotor assembly in which a rotor blade of the first rotor and a rotor blade of the second rotor are angularly aligned (as shown; figure 1) and a deployed configuration in which the rotor blade of the first rotor and the rotor blade of the second rotor are angularly misaligned (as shown; figure 2), the method comprising generating a damper force opposing the relative rotation between the first and second rotors in at least one of the direction towards the stowed configuration and the direction towards the deployed configuration (return spring 192, in the form of linear gas spring providing a damping functionality to damp a relative pivotal motion of the first propeller 110 and the second propeller 110; paragraph [0041]) wherein the damper is a rotary damper (damping a relative pivotal (rotary) motion; paragraph [0041]) that uses viscous fluid (gas, i.e., fluid inherently having some viscosity; paragraph [0041]). However, Ensslin does not explicitly teach a rotary fluid viscous damper as it relies on a linear gas spring.
Aubry is related prior art in that it deals with a damper that provides damping in the rotary direction in the field of aircraft flight control (column 3, lines 31-33). Aubry teaches a rotary fluid viscous damper that works by viscous fluid filled in a chamber engaging rotary motion of a plurality of rotor blades within the damper (see abstract). Aubry teaches this arrangement also provides twisting stiffness, i.e., rotary spring-like behavior, as well as damping function of the rotary motion (abstract; column 6, lines 20-22). Aubry also teaches this arrangement is very simple and very economical to produce and maintain during operation (column 7, lines 37-40). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date, to modify Ensslin’s return spring and damper assembly to incorporate Aubry’s rotary fluid viscous damper since Aubry’s rotary damper is capable of providing twisting stiffness (spring behavior in the rotary direction) and damping (Aubry) while also being very simple and very economical to produce and maintain during operation (column 7, lines 37-40).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Please note the difference in the scope of the currently amended claims having “rotary fluid viscous damper” which utilizes rotary motion of viscous fluid for damping and the previously claimed “rotary damper” of previous claim 4 and “fluid viscous damper” of claim 5 which includes all types of viscous damper that provides rotary damping. Therefore, the claim scope of the amendment filed on 10/29/2025 is different from the previous claim set. 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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/SANG K KIM/Primary Examiner, Art Unit 3745