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 1-7, 9-14 are currently pending. Claims 1-7, 9-14 are rejected.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 09, 2026 has been entered.
Response to Arguments
Applicant’s arguments, see Pg. 6-7 of the remarks, filed January 09, 2026, with respect to the rejection(s) of claim(s) 1 under 35 U.S.C. 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Itzel et al. (US 2018/0230841 A1).
Regarding Claim 1, Applicant asserts Willett, Jr. et al. (US 2013/0280047 A1) does not expressly teach the amended limitation of wherein the abradable material comprises a honeycomb structure having cells which are oriented in a radial direction with respect to said axis as claimed. The Office agrees. However, this limitation is believed to be obvious in view of Itzel as detailed in the rejection below.
Regarding the limitation of the axial distance (L1), this limitation was discussed in the rejection of Claim 1 on Pg. 5-6 of the Final Rejection filed July 16, 2025. Applicant has not presented any deficiencies of the rejection to support the assertion made in the remarks.
Regarding the limitations of two lips and two slots, Applicant has not provided any further arguments to support the assertion made. It is noted that the claim uses the terms “has”/“comprising” and is therefore open ended to the number of lips and slots. In other words, this limitation would be met by a rotor with more than two lips, since said rotor would at least have/comprise two. Even assuming if a narrower recitation is made, there is currently no evidence of record the number provides a new and unexpected result (see MPEP 2144.04, VI, B regarding duplication of parts).
No other arguments have been provided with respect to the remaining claims.
Claim Objections
Claims 1-7, 9-14 are objected to because of the following informalities:
Regarding Claim 1, Line 13 recites “preformed slots” while Line 20 recites “preformed annular slots”. These are believed to be the same limitation. This limitation was first introduced as “preformed annular slot”. Applicant is suggested to amend such that this limitation is consistently recited, i.e. either first recite “preformed annular slot” and have all other instances recite “preformed annular slot”, or have all recitations recite “preformed annular slot” instead of switching back and forth. Note that Claim 3 uses “preformed slot”.
Claims 2-7 and 9-14 are subsequently objected to for their dependencies upon a previously rejected claim.
Appropriate correction is required.
Claim Rejections - 35 USC § 112(b)
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 1-7, 9-14 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding Claim 1, a broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instance, the claim recites the broad recitations “a number of preformed slots” and “a number of lips” in Lines 13-14, and the claim also recites “two lips” and “two preformed annular slots” in Lines 19-20 which are the narrower statements of the ranges/limitations. The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Regarding Claim 3, Lines 3-4 and 7-8 recite “a preformed slot upstream”. It is unclear if these are the same slots recited in Claim 1 or introducing additional slots. Claim 1 requires “two preformed annular slots” corresponding to the lips of the rotor. For purposes of examination, it is believed these are intended to be the same slots.
Regarding Claim 5, Line 1 recites “the slot”. It is unclear which slot the claim is in reference to, since there are multiple slots within the context of the claim. Claim 1 appears to require two slots.
Claims 2, 4, 6-7, and 9-14 are subsequently rejected for their dependencies upon a previously rejected claim.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-7 and 9-14, as far as they are definite and understood, are rejected under 35 U.S.C. 103 as being unpatentable over Willett, Jr. et al. (US 2013/0280047 A1), hereinafter Willett in view of Itzel et al. (US 2018/0230841 A1), hereinafter Itzel.
Regarding Claim 1, Figures 1-3 of Willett teach three different embodiments of a labyrinth-type sealing device for a turbomachine (see paragraph [0001]), the device comprising: a rotor having an axis of rotation (not shown, will be below frame of view in Figures) and comprising external annular lips (22, unlabeled in Figures 1-2) extending around said axis, and a stator extending around the axis, this stator comprising an annular coating (14) made of abradable material (see paragraph [0019]) which extends around the lips (22) and which is configured to cooperate in operation with the lips (22) to form a labyrinth-type seal with respect to a flow of gas which is intended to flow axially from upstream to downstream (left to right in Figures) through the rotor, the coating (14) comprising an internal cylindrical surface (bottom-most surface of 14 with respect to Figures) extending around the lips (22) and which is configured to contact the lips (22) to form annular grooves extending around the axis by friction (material of coating noted to be abradable, grooves formed if abraded when contacted), wherein the surface comprises, upstream of each of the lips (22), a corresponding preformed annular slot (space in section 16) which extends around the axis and which is configured to receive said lip (22) in the event of an axial upstream displacement of the rotor with respect to the stator, a number of preformed slots (in section 16) being equal to a number of lips (22) of the rotor, wherein the rotor has two lips comprising an upstream and a downstream lip (see left and right lips in annotated Figure 1’ below), and wherein the surface comprises two preformed annular slots, an upstream slot and a downstream slot (see left and right slots in annotated Figure 1’ below) corresponding, respectively, to the upstream and downstream lips of the rotor [0019-0022]. See also annotated Figure 1’ below. The limitation of being for an aircraft turbomachine is treated as intended use of the claimed device. The claimed device meets all the recited structural limitations as noted above. While the embodiments of Figures 1-2 show the preformed annular slots (in section 16) downstream of the lips, paragraph [0020] discloses the increased clearance (formed in 16) could be applied to the left side, which results in the slots being upstream of the lips.
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Willett does not expressly teach wherein each of the number of slots is located at an axial distance between 1 and 20mm upstream of the corresponding one of the number of lips as claimed.
However, the courts have held various practices to be routine expedients, requiring only ordinary skill in the art. One such practice is a change in size. “Limitations relating to the size… were not sufficient to patentably distinguish over the prior art” (see MPEP 2144.04, IV, A). While an axial distance is illustrated in Figures 1 and 3 of Willett, the exact value of that distance is not explicitly described. Such an axial distance is subject to change depending upon the overall size of the device. For instance, if the device of Willett is made larger, the distance would be a larger value compared to if the device is scaled smaller. One of ordinary skill would change the overall size of the device by design choice. The claim only requires a particular value for the axial gap without relation to any other dimensional value of the device. Thus, the claims are considered encompassing merely a change in size of the device. For example, if a device has a gap of particular size, increasing the device as a whole would increase the gap size as well.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device taught by Willett such that each of the number of slots is located at an axial distance between 1 and 20mm upstream of the corresponding one of the number of lips, since the size of the device is a matter of design choice.
Willett does not expressly teach wherein the abradable material comprises a honeycomb structure having cells that are oriented in a radial direction with respect to said axis as claimed. However, such a honeycomb structure would have been obvious in view of Itzel.
Figures 7-8 teach a labyrinth sealing device comprising an abradable material (67), wherein the abradable material (67) comprises a honeycomb structure having cells (75) that are oriented in a radial direction (vertical with respect to view in Figure 7) with respect to said axis (horizontal with respect to view in Figure 7). Thus, Itzel exemplifies honeycomb structures are known in the art and predictably provide sufficient abradability for labyrinth sealings of turbines. Additionally, the repeated pattern of thin-walled structures provided promotes wearing without damaging the rotor blades [0039-0041].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device taught by Willett by simply substituting the solid or non-descript structure of the abradable portion such that the abradable material comprises a honeycomb structure having cells that are oriented in a radial direction with respect to said axis as exemplified by Itzel, since honeycomb structures are known configurations of abradable materials that predictably result in sufficient abradability that provides proper labyrinth sealings for turbines. Additionally, honeycombs provide the benefit of being thin-walled so that abradability without damage of the rotors is further promoted.
Regarding Claim 2, Willett and Itzel teach the device as set forth in Claim 1.
Figures 1-3 of Willett teach wherein the upstream and downstream lips (leftmost and rightmost lips, see annotated Figure 1’ above) are surrounded by two distinct cylindrical surfaces (internal surface of 14), respectively upstream and downstream, of the coating (14) [0019-0022]. See also annotated Figure 1’ above.
Regarding Claim 3, Willett and Itzel teach the device as set forth in Claim 2.
Figures 1-3 of Willett teach wherein in the case where the upstream and downstream lips (left and right 22, unlabeled in Figures 1-2) are surrounded by two distinct cylindrical surfaces (internal surface of 14), respectively upstream and downstream of the coating (left and right 14 that respectively corresponds with the lips), the upstream cylindrical surface comprises a preformed slot (formed in section 16) upstream of the upstream lip (22), and/or the downstream cylindrical surface comprises a preformed slot (formed in section 16) upstream of the downstream lip (22) [0019-0022]. See also annotated Figure 1’ above. While the embodiments of Figures 1-2 show the preformed annular slots (in section 16) downstream of the lips, paragraph [0020] discloses the increased clearance (formed in 16) could be applied to the left side, which results in the slots being upstream of the lips.
Regarding Claim 4, Willett and Itzel teach the device as set forth in Claim 2.
Figures 1-3 of Willett teach wherein the upstream and downstream cylindrical surfaces (left and right pairs of 14) are stepped and comprise different diameters. For instance, the leftmost (14) and middle (14) are clearly illustrated having different radial positions.
Regarding Claim 5, Willett and Itzel teach the device as set forth in Claim 4.
Figure 3 of Willett teaches wherein the slot (formed in 16, specifically the middle one) is interposed axially between the two cylindrical surfaces (inner surfaces of 14) [0022]. Alternatively, this is interpretable as the middle (16) of the Figure 2 embodiment, which while illustrated to be on the right side of (14), may be on the left side as well [0020].
Regarding Claim 6, Willett and Itzel teach the device as set forth in Claim 1.
Figure 3 of Willett teaches wherein the axial distance is less than half an axial distance between the two lips (left and middle 22). The halfway point between the two lips (22) is clearly illustrated in the zone of the slot (formed in 16) with portions in greater or less than the distance, therefore it satisfies the broadest reasonable interpretation of being “located at”.
Regarding Claims 6-7, for purposes of expediting prosecution Claim 6 is rejected again assuming the illustrated figures of Willett are insufficient, Willett teaches the device as set forth in Claim 1.
Willett does not expressly teach wherein the axial distance is less than or equal to (Claim 6) / greater than (Claim 7) half an axial distance between the two lips as claimed.
However, paragraph [0020] of Willett characterizes the slot (clearance) as part of abradable coating profile. And that clearance designs calculations would determine the details of the coating profile based on the specific geometry of the turbine in question. In other words, this shows that aspects of the slot, such as the exact positioning, would be calculated based on the geometry of the turbine the teachings are applied to.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device illustrated in Willett such that the axial distance is less than or equal to (Claim 6) / greater than (Claim 7) half an axial distance between the two lips as evidenced by paragraph [0020] of Willett, since one of ordinary skill would alter the coating profile based on the turbine the teachings are applied to.
Regarding Claim 9, Willett and Itzel teach the device as set forth in Claim 1.
Figures 1-2 of Willett teach wherein each slot (formed in 16) has a radial depth or dimension less than or equal to a radial thickness or dimension of a zone of the coating (14) in which this slot is formed [0019-0020]. See also annotated Figure 1’ above.
Regarding Claim 10, Willett and Itzel teach the device as set forth in Claim 1.
Figures 1-3 of Willett teach wherein each slot (formed in 16) has an axial dimension greater than or equal to half an axial thickness of a corresponding lip (22, unlabeled in Figures 1-2), the thickness being measured at a level of an external periphery of this lip. See also annotated Figure 1’ above. The slots are illustrated much greater than the peripheries of the lips.
Regarding Claim 11, Willett and Itzel teach the device as set forth in Claim 1.
Figures 1 and 3 of Willett teach wherein each slot (formed in section 16) is located in an axial distance from an upstream axial end of the cylindrical surface (inner surface of 14) in which that slot is formed. See also annotated Figure 1’ above. For example, the rightmost slot (16) in Figure 3 is spaced from the rightmost (14). Note while the embodiment of Figure 1 shows the preformed annular slots (in section 16) downstream of the lips, paragraph [0020] discloses the increased clearance (formed in 16) could be applied to the left side, which results in the slots being upstream of the lips.
Regarding Claim 12, Willett and Itzel teach the device as set forth in Claim 1.
Willett teaches wherein the rotor is a compressor or turbine blading, and the stator is a sealing ring carried by a casing of the compressor or turbine [0002-0003, 0019]. See also Figure 3, where ring (20) is carried by the casing surrounding it.
Regarding Claim 13, Willett and Itzel teach the device as set forth in Claim 1.
Willett does not expressly teach an aircraft turbomachine comprising at least one device as claimed. However, an aircraft turbomachine would have been obvious in view of Itzel.
At best, paragraph [0002] of Willett exemplifies the teachings to be applicable to rotary machines, including turbines.
Figure 12 of Itzel teaches a labyrinth-type sealing device having a rotor (16), a stator (65), a coating (78) made of abradable material and an abradable layer (67) [0038 (described of a different embodiment but same numerals for rotor and stator), 0047]. Paragraph [0030] notes the teachings may be used in a variety of gas turbines, including those of power generation and aircrafts. Thus, Itzel provides evidence that it is known for a gas turbine to be used as an aircraft turbomachine. Additionally, aircraft turbomachines benefit from teachings related to labyrinth-type sealing devices having abradable material. Thus, it would be reasonable to apply the teachings of Willett to an aircraft turbomachine so that the aircraft turbomachine may receive the benefits of Willett.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device taught by Willett-Itzel with an aircraft turbomachine comprising at least one device as evidenced by Itzel, since aircraft turbomachines are a known application of such a device and an aircraft turbomachine would be able to obtain the benefits of the teachings of Willett.
Regarding Claim 14, Willett and Itzel teach the device as set forth in Claim 1.
Willett does not expressly teach wherein said axial distance is between 1 and 5mm as claimed.
However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device taught by Willett such that said axial distance is between 1 and 5mm due to a design choice to have a change in proportions for the same reasons set forth in the rejection of Claim 1 above.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELTON K WONG whose telephone number is (408)918-7626. The examiner can normally be reached Mon-Fri 8:00AM - 5:00PM PST.
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/ELTON K WONG/Primary Examiner, Art Unit 3745