Prosecution Insights
Last updated: April 19, 2026
Application No. 18/568,086

Shaft-Grounding Device for Establishing an Electrically Conductive Connection Between a Rotatable Shaft and a Housing

Non-Final OA §102§112
Filed
Dec 07, 2023
Examiner
SCHLAK, DANIEL KEITH
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
ZF Friedrichshafen AG
OA Round
1 (Non-Final)
72%
Grant Probability
Favorable
1-2
OA Rounds
2y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 72% — above average
72%
Career Allow Rate
29 granted / 40 resolved
+4.5% vs TC avg
Strong +35% interview lift
Without
With
+35.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
31 currently pending
Career history
71
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
39.8%
-0.2% vs TC avg
§102
27.4%
-12.6% vs TC avg
§112
28.9%
-11.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 40 resolved cases

Office Action

§102 §112
DETAILED ACTION Claims 1-14 of U.S. Patent Application No. 18/568,086, filed on 7 December, 2023, were presented for examination. In the preliminary amendment also filed 7 December, 2023, claims 1-14 were canceled and new claims 15-28 were added. Claims 15-28 are currently pending in the application. 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 . Priority Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55. Information Disclosure Statement The information disclosure statement (IDS) submitted on 7 December, 2023, was filed before the mailing date of this Office action. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. Claim Rejections - 35 USC § 112 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. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim 28 is 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. Claim 28 recites the limitation "the shaft grounding ring” in line 6. There is insufficient antecedent basis for this limitation in the claim. 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. Claims 15-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by van Bezooijen (US 2019/0109520 A1). With respect to claim 15, van Bezooijen teaches a shaft grounding device [shaft grounding ring (FIG. 3) including elements 2, 3, 5, 7, 14, 16, 17] (see ¶ 0042) for electrically conductively connecting a rotatable shaft [1] and a housing [11] (see ¶ 0044 which recites “the dissipation body 10… with which the induced voltages can be dissipated away from the shaft 1 to a grounded housing 11), the shaft grounding device [2/3/5/7/14/16/17] being mechanically and electrically connected to the housing (see fig. 3, ¶ 0001, 0034, and 0044), the shaft grounding device [2/3/5/7/14/16/17] comprising: contact elements [flap sections 16, including web 22 and joint 26], each of the contact elements [16] being elastically bendable and electrically conductive (see ¶ 0049 which recites “flap sections 16, 17 in radial direction have different lengths and are contacting with elastic deformation the shaft 1… so that they can be bent elastically relative to the outer ring 14…” – also, ¶ 0051 recites “due to the elastic deformation of the flap sections 16, 17, it is achieved that they are contacting a really the shaft 1 and thus can reliably dissipate the voltages away from the shaft 1” which proves they are electrically conductive), the contact elements [16] forming a sliding contact (¶ 0053 recites “ensures for the period of use a constant reliable contact with the shaft 1…” – as the contact elements are immobile relative to the housing, this necessitates sliding contacting) that is electrically conductive with a circumferential surface [C] of the rotatable shaft [1] or a sleeve on the rotatable shaft [1], the contact elements [16] preloading the sliding contact (at running track 20 – see ¶ 0053 and 0055); and PNG media_image1.png 549 898 media_image1.png Greyscale at least one guide element [flaps 17 including web 27 and base 28], each of the at least one guide element [17] preventing the contact elements [16] from folding over when the shaft grounding device [2/3/5/7/14/16/17] is mounted onto the rotatable shaft [1] (¶ 0025 recites “in order for the flap sections of different lengths to be reliably elastically bent in the installation position… the joint ensures that the corresponding flap sections of different lengths can be elastically deformed to the required amount…”). {It is noted that although “folding over” is not explicitly discussed in the reference, the claim language is functional in nature, and can be interpreted such that any solid 3-dimensional item(s) interspersed between the contact elements would reduce the likelihood of folding of the contact elements by increasing the sum total of all restorative centering forces on the shaft, with each extra/additional item included between the housing and shaft constraining the shaft’s ability to deviate radially from its centered position, invariably reducing the incidence of a folding phenomenon in any individual contact element that is in the same sector as said item. Additionally, Applicant is directed to MPEP 2112, sub-sections I, II, and particularly III, for examples of the doctrine of inherency – although the Examiner has relied on a mechanics-based rationale to determine a common-sense conclusion that the contact elements [16] are less likely to fold due to the existence of the guide elements [17], which is sufficient because the “folding” is claimed as functional language, and therefore passive, inherency arguments are still relevant and Applicant is advised to read said section of the MPEP before responding}. With respect to claim 16/15, van Bezooijen teaches the device of claim 15, and further teaches wherein the contact elements [16] are arranged in a ring shape (see new annotated fig. 1 excerpt attached below), wherein the at least one guide element [17] comprises three guide elements spaced apart (numbered by the Examiner), each of the three guide elements [17] being positioned between a respective pair of adjacent contact elements [16] of the contact elements. PNG media_image2.png 516 424 media_image2.png Greyscale With respect to claim 17/15, van Bezooijen teaches the device of claim 15, and further teaches wherein the contact elements [16] are arranged in a ring shape, wherein the at least one guide element [17] is ring-shaped (in the new annotated excerpt of fig. 1 attached below, the Examiner has drawn a gray ring for the contact elements 16 and another gray ring for the guide elements – they both clearly follow their respective rings in orientation and geometry and are therefore ring-shaped). PNG media_image3.png 504 432 media_image3.png Greyscale With respect to claim 18/15, van Bezooijen teaches the device of claim 15, and further teaches: a holding element [inner clamping ring 3]; and a clamping element [outer clamping ring 2] (see ¶ 0042), wherein the contact elements [16] are held between the holding element [3] and the clamping element [2] (see new annotated excerpts of figs. 1 and 3 below, as well as ¶ 0042-0043 – it is noted that contact elements 16 are integral with ring 14 – see ¶ 0046 and 0048, the latter of which recites “ring 14 which is axially clamped across most of its radial width between the radial flanges 5, 7 of the clamping rings 2, 3…”), and PNG media_image4.png 522 873 media_image4.png Greyscale wherein the at least one guide element [17] is formed on or fastened to the holding element [3] or the clamping element [2] (it is also integral with ring 14 so is fastened to 2 and 3 by being clamped between them). With respect to claim 19/18/15, van Bezooijen teaches the device of claim 18, and further teaches wherein the holding element [2] or the clamping element [3] defines at least one recess (recess between 2 and 3, labeled by the Examiner in the new excerpt of figs. 1 and 3 below). For receiving at least one of the contact members [16] (again, contact members 16 are integral with ring 14, which is received in the recess – see ¶ 0048). PNG media_image5.png 518 874 media_image5.png Greyscale With respect to claim 20/15, van Bezooijen teaches the device of claim 15, and further teaches wherein at least one of the contact elements [16] has a cross-section which increases (at the transition from base 23 to web 22 – see ¶ 0058 and the enlarged snapshot of fig. 1 attached below, wherein the Examiner has labeled the radial inward direction and the overlap) radially inwardly and overlaps one or more of the at least one guide element [17] (it is noted that the overlap will come into effect after the installation of the shaft, as shown in fig. 3). PNG media_image6.png 551 442 media_image6.png Greyscale Claims 15 and 21-22 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Dorrestijn (WO 2015/086096 A1, reference provided herein). With respect to claim 15, Dorrestijn teaches a shaft grounding device [sealing arrangement 1] for electrically conductively connecting a rotatable shaft [rotating shaft 3] and a housing [2] (see last paragraph of page 6 – the housing is shown in in the embodiment of figs. 1-2 but not in the embodiment of figs. 3-5 – although the latter embodiment is being used herein, the housing is clearly part of it and is being interpreted as existing around the shaft grounding device as shown in figs. 1-2, even though it is not discussed in the embodiment of figs. 3-5), the shaft grounding device [1] being mechanically and electrically connected to the housing [2] (the abstract recites “a durable electrical connection between the machine parts…” it having been established in the beginning of the abstract that the first machine part is the housing 2 and the second machine part is the shaft 3), the shaft grounding device [1] comprising: PNG media_image7.png 552 957 media_image7.png Greyscale contact elements [carrier sections 5], each of the contact elements [5] being elastically bendable (the bottom of page 8 recites “the contact elements 6 are pressed radially onto the surface of the shaft 3 by means of spring 11…” – see also the weakening notch in figs. 4-5) and electrically conductive (see abstract), the contact elements [5] forming a sliding contact (between contact element 6 and shaft 3) that is electrically conductive with a circumferential surface [C] of the rotatable shaft [3] (see abstract) or a sleeve on the rotatable shaft [3], the contact elements [5] preloading the sliding contact (between 6 and C, with or without the spring 11, due to the weakening notch); and at least one guide element [contact element 6], each of the at least one guide element [6] preventing the contact elements [5] from folding over when the shaft grounding device [1] is mounted onto the rotatable shaft [3] (if the guide elements 6 were removed from the contact elements, the latter would be more prone to deformation and thus potential folding, since the guide elements 6 are described as consisting of graphite which is a very stiff material). With respect to claim 21/15, Dorrestijn teaches the device of claim 15, and further teaches wherein at least one of the contact elements [5] encompasses one or more of the at least one guide element [6] (it encompasses it via receiving it in a recess, labeled by the Examiner in the annotated excerpt of fig. 4 attached below). PNG media_image8.png 545 301 media_image8.png Greyscale With respect to claim 22/21/15, Dorrestijn teaches the device of claim 21, and further teaches wherein each of the at least one of the contact elements [5] defines a recess (still referring to the fig. 4 excerpt above, wherein the Examiner has labeled the recess defined by the pockets in elements 5). Claims 15 and 23 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Timm (WO 2020/194191 A1, provided herein). With respect to claim 15, Timm teaches a shaft grounding device [10] for electrically conductively connecting a rotatable shaft (represented by “diameter d” in fig. 7 – see abstract and top half of page 9) and a housing (mentioned in the abstract, claim 1, and page 6, line 8), the shaft grounding device [10] being mechanically and electrically connected to the housing (still referring to page 6 which describes the embodiment of figs. 1-5 but whose general discussion is taken to also refer to the alternative embodiment of figs. 6-9, used herein), the shaft grounding device [10] comprising: PNG media_image9.png 473 892 media_image9.png Greyscale contact elements [fibers 18], each of the contact elements [18] being elastically bendable (all fibers are elastically bendable) and electrically conductive (see page 8, lines 6-8), the contact elements [18] forming a sliding contact (see last two lines of abstract) that is electrically conductive with a circumferential surface of the rotatable shaft (see col. 3, lines 30-31) or a sleeve on the rotatable shaft, the contact elements [18] preloading the sliding contact (if the elements 18 are pushed until they touch, then the preloading of the sliding contact results or else they would stop touching); and at least one guide element [cartridge 16], each of the at least one guide element [16] preventing the contact elements [18] from folding over when the shaft grounding device [10] is mounted onto the rotatable shaft. {It is noted that although “folding over” is not explicitly discussed in the reference, the claim language is functional in nature, and can be interpreted such that any 3-dimensional solid item(s) protruding toward the shaft, and stiffer than the fibers (which guide elements 16 must be because by being 3-dimensional in nature, they can resist compressive stress unlike a 2-dimensional fiber), would necessarily reduce the likelihood of folding of the contact elements by increasing the sum total of all restorative centering forces on the shaft, with each extra/additional 3-dimensional item included between the housing and shaft constraining the shaft’s ability to deviate radially from its centered position, invariably reducing the incidence of a folding phenomenon in any individual contact element. Additionally, Applicant is directed to MPEP 2112, sub-sections I, II, and particularly III, for examples of the doctrine of inherency – although the Examiner has relied on a mechanics-based rationale to determine a common-sense conclusion that the contact elements [18] are less likely to fold due to the existence of the guide elements [16], which is sufficient because the “folding” is claimed as functional language, and therefore passive, inherency arguments are still relevant and Applicant is advised to read said section of the MPEP}. With respect to claim 23, Timm teaches the device of claim 15, and further teaches wherein one guide element [16] has no contact with the circumferential surface (represented by “d” which is outer diameter of the shaft, in fig. 7) when the shaft grounding device [10] is mounted onto the rotatable shaft {the top of page 9 recites “the cartridges (16) and conductive fibers (18) mounted thereon are moved radially inwardly into the axial cavity (14) such that free ends (18A) of the conductive fibers (18) jointly lie circumferentially along a first virtual circle or circumference “d” having a first predetermined shaft accommodating diameter…” – since the fibers 18 extend inwardly toward the shaft from the cartridges and only the free ends 18A touch the shaft, the guide element has no contact with the shaft surface during normal operation}. PNG media_image10.png 468 890 media_image10.png Greyscale Claims 15 and 24-28 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Franke (DE 102018208823 A1, provided by Applicant in IDS, but cited herein again and provided with a different machine translation, which will be used by the Examiner). With respect to claim 15, Franke teaches a shaft grounding device [contact element 6] for electrically conductively connecting a rotatable shaft [4] and a housing [external component 5] (see abstract and fig. 1), the shaft grounding device [6] being mechanically and electrically connected to the housing [5] (see abstract and ¶ 0005 of the provided translation), the shaft grounding device [6] comprising: PNG media_image11.png 476 1056 media_image11.png Greyscale contact elements [lamellae 12], each of the contact elements [12] being elastically bendable and electrically conductive {¶ 0023 recites “the lamellae 12 are flexible or resilient and form a sliding contact between the rotatable rotor shaft 4 and the contacting element 6…” – the abstract establishes that they are electrically conducive as being part of “conductive body (8)”}, the contact elements [12] forming a sliding contact that is electrically conductive with a circumferential surface of the rotatable shaft [4] (see last seven lines of the abstract and ¶ 0008) or a sleeve on the rotatable shaft, the contact elements [12] preloading the sliding contact (¶ 0008 recites “the at least one flexible lamella or lamella spring is formed on the body. The lamella is in this case a thin, disk-shaped element, for example in the form of a leaf spring, which can fit snugly against the outside of the shaft…”); and at least one guide element [slip ring 7], each of the at least one guide element [7] preventing the contact elements [12] from folding over when the shaft grounding device [1] is mounted onto the rotatable shaft [4] (¶ 0024 recites “here, end pieces 13 of the finger-shaped lamellae 12 are arranged resting on an end face 14 of the slip ring 7. Here, the slip ring forms a step in an outer side of the rotor shaft…” Thus, the slip ring, by being a solid annular object contacting the shaft and surrounding it, will prohibit radial drifting/movement of the shaft away from its axis, in such a way that the contact elements 12 cannot be folded/bent at all.) With respect to claim 24/15, Franke teaches the shaft grounding device [10] of claim 15, Franke further teaches a transmission [electric drive unit including electric machine 1] for a motor vehicle (see abstract which recites “an electric drive unit of a motor vehicle”), comprising; a housing [5]; a shaft [4] mounted in the housing [5] (see abstract and ¶ 0011, 0012, and 0024-0025); the shaft grounding device [6] of claim 15 (see rejection of claim 15 above), the shaft grounding device [6] grounding the shaft [4] (see ¶ 0007 and 0024). With respect to claim 25/24/15, Franke teaches the transmission of claim 24, wherein the shaft [4] forms an output shaft of the transmission [1] (see ¶ 0002). With respect to claim 26/24/15, Franke teaches the transmission of claim 24, and further comprises an electric machine [1 including a stator and a rotor], the shaft [4] being drivable by the electric machine [1] (see ¶ 0002). With respect to claim 27/15, Franke teaches the shaft grounding device [10] of claim 15, Franke further teaches an electric axle drive unit [electric drive unit including electric machine 1] for a motor vehicle (see abstract which recites “an electric drive unit of a motor vehicle”), the electric axle drive unit comprising; a housing [5]; a shaft [4] mounted in the housing [5] (see abstract and ¶ 0011, 0012, and 0024-0025); the shaft grounding device [6] of claim 15 (see rejection of claim 15 above), the shaft grounding device [6] grounding the shaft [4] (see ¶ 0007 and 0024). PNG media_image12.png 605 321 media_image12.png Greyscale With respect to claim 28/15, Franke teaches the shaft grounding device [10] of claim 15, Franke further teaches an electric machine [electric drive unit including electric machine 1] comprising; a housing [5]; a rotationally fixed stator [2] (see ¶ 0002 and fig. 1 excerpt attached above); a rotatable rotor [3] coupled to a rotor shaft [4], the rotor shaft [4] being mounted in the housing [5] (still referring to fig. 1 and ¶ 0002); the shaft grounding device [6] of claim 15 (see rejection of claim 15 above), the shaft grounding device [6] grounding the rotor shaft [4] (see ¶ 0007 and 0024). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Figs. 5-6 of US 2021/0115974 A1 appear to anticipate some claims of the application. PNG media_image13.png 205 284 media_image13.png Greyscale PNG media_image14.png 256 279 media_image14.png Greyscale Fig. 2 of US 2016/0215824 A1 also seems relevant to claim 1 and some dependent claims (although element 5 is a seal). PNG media_image15.png 452 457 media_image15.png Greyscale Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL K SCHLAK whose telephone number is (703)756-1685. The examiner can normally be reached Monday - Friday, 9:30 am - 6:00 pm EST. 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, Seye Iwarere can be reached at (571) 270 - 5112. 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. /Daniel K Schlak/Examiner, Art Unit 2834 /OLUSEYE IWARERE/Supervisory Patent Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Dec 07, 2023
Application Filed
Feb 07, 2026
Non-Final Rejection — §102, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12597835
ROTOR HAVING A SQUIRREL CAGE
2y 5m to grant Granted Apr 07, 2026
Patent 12580432
ELECTRIC MACHINE AND MOTOR VEHICLE WITH WALL ELEMENT AND TOOTH HEAD RING
2y 5m to grant Granted Mar 17, 2026
Patent 12567787
ELECTRIC MOTOR ROTOR INCLUDING END RING RESTRAINER
2y 5m to grant Granted Mar 03, 2026
Patent 12556054
STATOR WITH IMPROVED BUSBARS AND MOTOR INCLUDING THE SAME
2y 5m to grant Granted Feb 17, 2026
Patent 12549056
Electric Machine Frame Fastenerless Covers
2y 5m to grant Granted Feb 10, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

1-2
Expected OA Rounds
72%
Grant Probability
99%
With Interview (+35.4%)
2y 8m
Median Time to Grant
Low
PTA Risk
Based on 40 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month