Prosecution Insights
Last updated: April 19, 2026
Application No. 18/578,476

BRUSHLESS MOTOR

Final Rejection §103
Filed
Jan 11, 2024
Examiner
KENERLY, TERRANCE L
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Dyson Technology Limited
OA Round
2 (Final)
73%
Grant Probability
Favorable
3-4
OA Rounds
2y 8m
To Grant
88%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
828 granted / 1129 resolved
+5.3% vs TC avg
Strong +15% interview lift
Without
With
+15.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
33 currently pending
Career history
1162
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
55.7%
+15.7% vs TC avg
§102
28.8%
-11.2% vs TC avg
§112
11.2%
-28.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1129 resolved cases

Office Action

§103
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 Arguments Applicant's arguments filed 12/22/2025 have been fully considered but they are not persuasive. In response to applicant’s arguments regarding claim 1 and how it would be improper to combine the references, this is a mere allegation of patentability and is not found persuasive. As for applicant’s argument applicant’s allegations about Sullivan and Childe and how one having ordinary skill in the art would not be motivated to switch places of the o-ring, this is not found persuasive because the motivation was provided. Still further, the size, thickness, and springiness are all features considered when picking an o-ring for such a task (location of o-ring whether it is going to be close to an impeller or far from the impeller) and those features fall within the realm of one having ordinary skill in the art. As for applicant’s allegations regarding there being no articulated rationale to support the rejection, this too is not found persuasive because the rationale was provided in the previous rejection and in the response to applicant’s arguments in this rejection. Thus, the swapping of the o-ring of Childe into Sullivan’s invention is conceivably compatible. In response to applicant’s arguments regarding claim 2, this is not found persuasive for reasons stated above (the selection of the stiffness, size, thickness fall within the realm of one having ordinary skill in the art). In response to applicant’s arguments regarding claim 3, this is not found persuasive for the similar reasons as why applicant’s arguments regarding claim 2 were not found persuasive. In response to applicant’s arguments regarding claim 5, this is not found persuasive as Shore A hardness measures how flexible/stiff something is. In response to applicant’s argument regarding claim 8, this is not found persuasive for reasons stated above and that the o-ring is meant to be used with the configuration of Sullivan that does not have the recess. 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. 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. Claim(s) 1-6, 8, 13-15 and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sullivan (US 20180363669) in view of Childe et al. (WO 2005029680). Claim 1, Sullivan teaches: A brushless motor 10 comprising a stator assembly , a rotor assembly 12 rotatable relative to the stator assembly 16, 18, 20 & 22, and a frame 14 within which the stator assembly (within slots, para 0017) and the rotor assembly are housed (fig 4), wherein the rotor assembly comprises a shaft 30, first and second bearings 40 & 38 attached to the shaft (fig 4), a permanent magnet 32 attached to the shaft between the first and second bearings (fig 4), an impeller 42 attached to the shaft (fig 4), the first bearing located further away from the impeller than the second bearing (fig 4); but does not disclose an o-ring mounted between the first bearing and the frame. Childe et al. discloses that an o-ring mounted between the first bearing and the frame 23 (or housing of the motor, fig 4) to reduce noise and vibrations which improves the reliability of the machine (col 3 3rd para). As a result, it would have been obvious to a person having ordinary skill in the art prior to the invention being effectively filed to modify the invention of Sullivan with an o-ring mounted between the first bearing and the frame, as taught by Childe et al. so as to improve the reliability of the machine. Claim 2, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the o-ring (18a & 18b of Childe et al., fig 4) is mounted between the first bearing (9 of Childe et al., fig 4) and the frame (of Childe et al., fig 4) such that the o-ring is able to move axially relative to the frame without deformation of the o-ring (since the o-ring is held in a recess on the end cap 11 and the frame has a flat surface, fig 4 MPEP 2112). Claim 3, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the o-ring (18a & 18b of Childe et al., fig 4) is mounted between the first bearing (9 of Childe et al., fig 4) and the frame (of Childe et al., fig 4) such that the o-ring is substantially uncompressed (since the o-ring is held in a recess on the end cap 11 and the frame has a flat surface, fig 4 MPEP 2112). Claim 4, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the o-ring (of Childe et al.) comprises a substantially circular cross-sectional shape (figs 3 & 4) when mounted between the first bearing and the frame 23 (of Childe et al.). Claim 5, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the o-ring comprises a radial stiffness in the region of 1.0x106 N/m to 4.0x106 N/m (since the material of Childe et al. o-ring is EPDM which has a Shore A hardness of 30-90, the examiner contends that the limitations regarding the radial stiffness are met, page 7 lines 20-28 and MPEP 2112). Claim 6, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the o-ring comprises a material having a Shore A hardness in the region of 65-90 (since the material of Childe et al. o-ring is EPDM which has a Shore A hardness of 30-90, page 7 lines 20-28 and MPEP 2112). Claim 8, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1 wherein the o-ring (18a & 18b of Childe et al., fig 4) contacts the frame (of Childe et al., fig 4) over a region that is substantially smooth, and the o-ring is able to move axially over the region of the frame (since the o-ring is held in a recess on the end cap 11 and the frame has a flat surface, fig 4 MPEP 2112). Claim 13, Sullivan in view of Childe et al. teach: The brushless motor as claimed in Claim 1, wherein the brushless motor comprises a stopper (the end cap of Childe et al. is a stopper, fig 4) for inhibiting radial motion of the rotor assembly relative to the frame. Claim 14, Sullivan in view of Childe et al. teach: The brushless motor as claimed in claim 13, wherein the stopper comprises an end cap (the end cap of Childe et al. is a stopper, fig 4) positioned to at least partially overlie the first bearing (fig 4 of Childe et al.), and at least a portion of the end cap is located between the first bearing and the frame (fig 4 of Childe et al.). Claim 15, Sullivan in view of Childe et al. teach: The brushless motor as claimed in claim 14, wherein a first distance between the portion of the end cap located between the first bearing (since the bearing is fixed to the end cap, Childe et al. fig 4) and the frame is less than a second distance (The air gap between the stator and rotor represents the 2nd distance which is greater than the 1st distance since there is no gap between the end cap and the bearing, MPEP 2112) between the permanent magnet and the stator assembly. Claim 21, Sullivan in view of Childe et al. teach: A vacuum cleaner 30 (of Childe et al., fig 5) comprising the brushless motor as claimed in Claim 1. Claim(s) 7 & 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sullivan in view of Childe et al. and in further view of Tsunoda et al. (JP 2006174581). Claim 7, Sullivan has been discussed above, re claim 1; but does not teach that the o-ring contacts an outer surface of the first bearing over a region that is substantially smooth, and the o-ring is able to move axially over the region of the outer surface. Tsunoda et al. teach that the o-ring 3 contacts an outer surface of the first bearing 1 over a region that is substantially smooth to provide a water proof structure for the shaft. As for the o-ring being able to move axially over a region of the outer surface of the bearing, this would be realized once Tsunoda et al. teaching is applied to the motor structure of Sullivan (since o-rings can function as dynamic seals) and keeping the same motivation which improves the motor’s reliability. As a result, it would have been obvious to a person having ordinary skill in the art before the invention was effectively filed to modify the invention of Sullivan so that the o-ring contacts an outer surface of the first bearing over a region that is substantially smooth, as taught by Tsunoda et al. so as to improve the reliability of the motor. Claim 9, Sullivan has been discussed above, re claim 1; but does not teach that the frame comprises a channel having a first portion with a first diameter, a second portion with a second diameter less than the first diameter, and a step defining a transition from the first portion to the second portion, the step defining an axial stop for inhibiting axial movement of the o-ring. Tsunoda et al. teach that the frame 2 comprises a channel (annotated fig 1 below) having a first portion (annotated fig 1 below) with a first diameter, a second portion (annotated fig 1 below) with a second diameter less than the first diameter, and a step (annotated fig 1 below) defining a transition from the first portion to the second portion, the step defining an axial stop for inhibiting axial movement of the o-ring (since the aforementioned limitations are met) to provide a water proof structure for the shaft. As for the o-ring being able to move axially over a region of the outer surface of the bearing, this would be realized once Tsunoda et al. teaching is applied to the motor structure of Sullivan (since o-rings can function as dynamic seals) and keeping the same motivation which improves the motor’s reliability. PNG media_image1.png 669 503 media_image1.png Greyscale As a result, it would have been obvious to a person having ordinary skill in the art before the invention was effectively filed to modify the invention of Sullivan so that the frame comprises a channel having a first portion with a first diameter, a second portion with a second diameter less than the first diameter, and a step defining a transition from the first portion to the second portion, the step defining an axial stop for inhibiting axial movement of the o-ring, as taught by Tsunoda et al. so as to improve the reliability of the motor. Claim 10, Sullivan in view of Childe et al. and further in view of Tsunoda et al. teach: The brushless motor as claimed in claim 9, wherein the step defines an axial stop for inhibiting axial movement of the o-ring in a direction toward the impeller (of Sullivan) since the o-ring rests against the stop (see annotated fig above). Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sullivan in view of Childe et al. and in further view of Kanehara (JP 2000156952). Claim 11, Sullivan has been discussed above, re claim 1; but does not teach that the rotor assembly comprises a pre-load spring for applying a load to an outer race of the first bearing. Kanehara teaches that the rotor assembly 34 comprises a pre-load spring 4 for applying a load to an outer race 3 of the first bearing 3 to reduce the noise in the motor which leads to an improved reliability of the motor. As a result, it would have been obvious to a person having ordinary skill in the art before the invention was effectively filed to modify the invention of Sullivan so that the rotor assembly comprises a pre-load spring for applying a load to an outer race of the first bearing, as taught by Kanehara so as to improve the reliability of the motor. Allowable Subject Matter Claims 12 and 16 are allowed. Claims 17-20 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. Conclusion THIS ACTION IS MADE FINAL. 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 TERRANCE L KENERLY whose telephone number is (571)270-7851. The examiner can normally be reached M-F 9am-5pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christopher Koehler can be reached at 5712723560. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /TERRANCE L KENERLY/Primary Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Jan 11, 2024
Application Filed
Sep 15, 2025
Non-Final Rejection — §103
Dec 22, 2025
Response Filed
Feb 21, 2026
Final Rejection — §103 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
73%
Grant Probability
88%
With Interview (+15.1%)
2y 8m
Median Time to Grant
Moderate
PTA Risk
Based on 1129 resolved cases by this examiner. Grant probability derived from career allow rate.

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