Prosecution Insights
Last updated: April 19, 2026
Application No. 18/930,123

COUNTER PRESSURE CHAMBER FOR HYDRAULIC CLUTCH

Final Rejection §102§103
Filed
Oct 29, 2024
Examiner
FLUHART, STACEY A
Art Unit
3655
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Dana Belgium N V
OA Round
4 (Final)
83%
Grant Probability
Favorable
5-6
OA Rounds
2y 3m
To Grant
97%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
681 granted / 824 resolved
+30.6% vs TC avg
Moderate +14% lift
Without
With
+14.0%
Interview Lift
resolved cases with interview
Typical timeline
2y 3m
Avg Prosecution
25 currently pending
Career history
849
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
40.3%
+0.3% vs TC avg
§102
24.6%
-15.4% vs TC avg
§112
33.2%
-6.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 824 resolved cases

Office Action

§102 §103
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 . Claim Rejections - 35 USC § 102 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 3, and 6 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Wilton (US 2012/0145511). Claim 1 Wilton discloses a hydraulic clutch comprising: a piston (44) comprising a first portion and a second portion, where the first portion and the second portion include and are contiguous via a step section (see annotated FIG. 1); a drum (22); a washer (24 and associated/ interconnected washer noted in annotated FIG. 1 as “washer”); a first seal (see annotated FIG. 1) radially surrounding the piston between the first portion of the piston and the drum (22); a second seal (see annotated FIG. 1) radially surrounding the washer between the washer and the second portion of the piston, where the first seal and the second seal share a common diameter and are positioned in parallel (see annotated FIG. 1 below); an actuation chamber (52) defined between the piston and the drum, where the actuation chamber is fluidly coupled to a work fluid supply channel (64 or any channels or ports along supply path) and the first seal fluidly seals the actuation chamber in a radial direction parallel to a first diameter of the piston; and a counter-pressure chamber (54) defined between the piston and the washer, where a rotational axis of the counter-pressure chamber is parallel to a rotational axis of the actuation chamber, where a diameter of the actuation chamber is equal to a diameter of the counter-pressure chamber (same diameter as “common diameter”), where the counter-pressure chamber is fluidly coupled to a work fluid overflow channel (60) and fluidly coupled to a second fluid passage (66 or input channel to 66) via a second channel (see annotated FIG. 1), where the second channel radially directs working fluid, and where the second seal fluidly seals the actuation chamber. [AltContent: textbox (Second channel)][AltContent: arrow][AltContent: textbox (Common diameter)][AltContent: connector][AltContent: textbox (Washer)][AltContent: arrow][AltContent: arrow][AltContent: textbox (Second portion)][AltContent: textbox (Step section)][AltContent: arrow][AltContent: textbox (first seal)][AltContent: arrow][AltContent: textbox (First portion)][AltContent: arrow][AltContent: textbox (Second seal)][AltContent: arrow] PNG media_image1.png 428 436 media_image1.png Greyscale The section between the first and second portions is interpreted as a stepped portion because it steps outward from one diameter to the next. There is no requirement that the stepped portion be 90 degrees until the further narrowing of this feature in claim 4. Claim 3 Wilton discloses where the counter-pressure chamber is configured to provide a first centrifugal load, and the actuation chamber is configured to provide a second centrifugal load, and where the first centrifugal load is equal to the second centrifugal load (see paragraph [0032] discloses that the assembly is centrifugally balanced). Claim 6 Wilton discloses where the actuation chamber (52) is configured to drive the piston (44). Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 2, 4-6, 13-16 and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang (CN 112443590A) in view of Liu (CN 113062932A). Claim 1 Wang discloses a hydraulic clutch comprising: a piston (34) comprising a first portion and a second portion, where the first portion and the second portion include and are contiguous via a section (region around 341 that interconnects the two diametered portions of the piston); a drum (31); a washer (38); a first seal (80) radially surrounding the piston between the first portion of the piston and the drum; a second seal (see annotated FIG. 1) radially surrounding the washer between the washer and the second portion of the piston, where the first seal and the second seal are positioned in parallel (see FIG. 1); an actuation chamber (37) defined between the piston (34) and the drum (31), where the actuation chamber (37) is fluidly coupled to a work fluid supply channel (13) and the first seal (80) fluidly seals the actuation chamber in a radial direction parallel to a first diameter of the piston; and a counter-pressure chamber (35) defined between the piston (34) and the washer (38), where a rotational axis of the counter-pressure chamber is parallel to a rotational axis of the actuation chamber (see FIG. 1), where the counter-pressure chamber is fluidly coupled to a work fluid overflow channel (381) and fluidly coupled to a second fluid passage (15) via a second channel (11), where the second channel (11) radially directs working fluid, and where the second seal fluidly seals the actuation chamber. Alternatively, Wang discloses where the counter-pressure chamber is fluidly coupled to a work fluid overflow channel (11) and fluidly coupled to a second fluid passage (311) via a second channel (341), where the second channel (341) radially directs working fluid. [AltContent: textbox (First surface)][AltContent: arrow][AltContent: textbox (Second seal)][AltContent: arrow][AltContent: textbox (Second portion)][AltContent: textbox (First portion)][AltContent: arrow][AltContent: arrow] PNG media_image2.png 762 850 media_image2.png Greyscale Wang discloses that the two portions of the piston have different outer diameters but does not necessarily disclose that the two portions of the piston are connected by a step section. Wang does not disclose where the first seal and the second seal share a common diameter. Wang does not disclose where a diameter of the actuation chamber is equal to a diameter of the counter-pressure chamber. However, Liu discloses a fluid clutch with a piston having three seals, two outer seals outside the piston against a drum and one inner seal inside the piston against a washer, as in Wang, but with the first outer seal set inward from the other outer seal in alignment with the inner seal at a common diameter and the two portions of the piston connected by a step section (see annotated partial FIG. 1 at the right below, mirror imaged to match the orientation of FIG. 1 of Wang at the left below). [AltContent: textbox (First outer seal)][AltContent: textbox (Other outer seal)] [AltContent: arrow][AltContent: arrow][AltContent: arrow][AltContent: arrow] [AltContent: arrow][AltContent: arrow][AltContent: arrow] PNG media_image2.png 762 850 media_image2.png Greyscale PNG media_image3.png 382 524 media_image3.png Greyscale [AltContent: textbox (Step section)][AltContent: textbox (Inner (recited second) seal)] It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to have modified Wang to have moved the smaller portion of the piston to be radially further inward as taught by Liu in order to provide more space for the clutch that is positioned surrounding the inner piston, for example to provide a greater surface area of the outer clutch or to provide more space for a larger return spring or to move the entirety of the outer clutch compensation chamber to be to the right of the larger diameter portion of the inner piston which would condense the arrangement overall. Claim 2 Wang under the alternative interpretation discloses where a shaft (10) comprises a portion (e.g., the middle portion of 13) of the work fluid supply channel (13) having a second diameter and a portion (any portion of 11) of the work fluid overflow channel (11) having a third diameter, and where the second diameter is equal to the third diameter (see FIG. 1 illustrating channel 12 overlapping the innermost and outermost diameters of channel 11). Claim 4 Wang discloses where the washer includes a stepped portion that is configured to have a spring positioned therein, where the stepped portion of the washer is a 90-degree offset between a first diameter and a second diameter of the washer (see annotated partial FIG. 1 below), and where the step section of the piston is a 90-degree offset between the first portion of the piston and the second portion of the piston (see step portion of Liu, modified to be added into Wang based on the rejection of claim 1). [AltContent: textbox (Stepped portion)] [AltContent: arrow] [AltContent: textbox (Second diameter)][AltContent: arrow][AltContent: textbox (First diameter)][AltContent: arrow] PNG media_image4.png 344 284 media_image4.png Greyscale Claim 5 Wang discloses where the washer includes a washer diameter (same as “first diameter” in rejection of claim 4) that is in contact with the second seal. Claim 6 Wang discloses where the actuation chamber (37) is configured to drive the piston (34). Claim 13 Wang discloses a hydraulic clutch, comprising: a drum (31) comprising a first cavity; a piston (34) comprising a first portion (see annotated figure in rejection of claim 1) including a groove (groove in which 80 sits) that depresses radially into a first surface of the first portion, a second portion (see annotated figure in rejection of claim 1) comprising a second cavity, and a connection that is contiguous between the first portion and the second portion, where a circumferentially outer surface of the first portion and a circumferentially outer surface of the second portion are both in face sharing contact with the drum (31) (see only figure); a washer (38) positioned in the second cavity of the piston; a first seal (80) positioned in the groove of the first portion of the piston and radially surrounding the piston between the first portion of the piston and the drum; a second seal (see annotated figure in rejection of claim 1) positioned in the second cavity of the second portion of the piston and radially surrounding the washer between the second portion of the piston and the washer; an actuation chamber (37) defined between a first surface (right surface) of the piston (34) and the drum (31); a counter-pressure chamber (35) defined in the second cavity between a second surface (left surface) of the piston (34) and the washer (38) the second surface opposing the first surface; and a spring (39 including the associated end supports) housed in the counter-pressure chamber, where the spring is in surface sharing contact with, and positioned between, the piston (34) and the washer (38). Wang discloses that the two portions of the piston have different outer diameters but does not necessarily disclose that the two portions of the piston are connected by a step section. Wang does not disclose where a diameter of the actuation chamber is equal to a diameter of the counter-pressure chamber. However, Liu discloses a fluid clutch with a piston having three seals, two outer seals outside the piston against a drum and one inner seal inside the piston against a washer, as in Wang, but with the first outer seal set inward from the other outer seal in alignment with the inner seal at a common diameter and the two portions of the piston connected by a step section (see annotated partial FIG. 1 at the right below, mirror imaged to match the orientation of FIG. 1 of Wang at the left above in rejection of claim 1). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to have modified Wang to have moved the smaller portion of the piston to be radially further inward as taught by Liu in order to provide more space for the clutch that is positioned surrounding the inner piston, for example to provide a greater surface area of the outer clutch or to provide more space for a larger return spring or to move the entirety of the outer clutch compensation chamber to be to the right of the larger diameter portion of the inner piston which would condense the arrangement overall. Claim 14 Wang discloses a hub (32), where the drum (31) is positioned about the hub (32) such that portions of the hub (32) are housed in the first cavity of the drum (31) (see only figure). Claim 15 Wang discloses where the actuation chamber (37) is enclosed in the first cavity of the drum (31), and the first surface (right surface and specifically the portion of the right surface that is also labeled as “first surface” in annotated figure in rejection of claim 1) of the piston (34) is planar in a vertical direction perpendicular to a central axis (horizontal dotted line figure) of the hydraulic clutch. Claim 16 Wang discloses where the spring (39) is configured to apply a force that is opposite (to the right in only figure) to direction of engagement (to the left) of the piston (34). Claim 21 Wang discloses where the work fluid overflow channel (11) is fluidly coupled to a passage (15) configured to expel work fluid. Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Hering (US 5,538,121). Claim 7 Wang discloses where the drum (31) is fixedly coupled to a plurality of separator plates (outer plates of 33). Wang does not disclose wherein the drum is fixedly coupled to an output gear. However, Hering discloses a clutch where the outer clutch hub includes a gear (44) connected thereto in order to transfer torque to/from the outer clutch hub in a simple manner. As so modified, Wang would disclose where rotational energy is transferred to the output gear when the piston is actuated to engage the plurality of separator plates with a plurality of friction plates since any torque from the inner hub through the clutch would also travel to the added input gear. Claim(s) 8-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Ikemoto. Claim 8 Wang discloses a hub (hub of 38) but does not disclose this hub is fixedly connected to an input gear. Ikemoto discloses a hub (3) fixedly coupled to an input gear (gear of 5). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to have modified Wang so that the output hubs (Wang, 22 and 32) are connected to a gear transmission in order to provide multiple gear ratios and/or in order to change the gear ratio to optimize the transmission. Claim 9 Wang discloses where a plurality of separator plates (outer plates of 33) are fixedly coupled to the drum (31) and a plurality of friction plates (inner plates of 33) are fixedly coupled to the hub (3) (see FIG. 1). Claim 10 Wang discloses where the plurality of friction plates (inner plates of 33) are selectively engaged with the plurality of separation plates (outer plates of 33) via actuation of the piston (34). Claim 11 Wang discloses where the drum (31) is positioned about the piston (34) and the piston (34) is positioned between the hub (3) and a portion of the drum (31) (see FIG. 1). Claim 12 Wang as modified discloses wherein the input gear (from Ikemoto, gear of 5 added to inside of hub 32) and the hub (3) are supported on a shaft (21) by bearings (60 and/or 50 as a thrust bearing) that enable the input gear and the hub to rotate independently of the shaft. 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 STACEY A FLUHART whose telephone number is (571)270-1851. The examiner can normally be reached M-Th 9AM-7PM. 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, Ernesto Suarez can be reached at 571-270-5565. 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. /STACEY A FLUHART/ Primary Examiner, Art Unit 3655
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Prosecution Timeline

Oct 29, 2024
Application Filed
Feb 22, 2025
Non-Final Rejection — §102, §103
May 27, 2025
Response Filed
Jul 08, 2025
Final Rejection — §102, §103
Sep 19, 2025
Request for Continued Examination
Oct 02, 2025
Response after Non-Final Action
Oct 21, 2025
Non-Final Rejection — §102, §103
Jan 26, 2026
Response Filed
Mar 18, 2026
Final Rejection — §102, §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

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2y 5m to grant Granted Mar 31, 2026
Patent 12577989
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2y 5m to grant Granted Mar 17, 2026
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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
83%
Grant Probability
97%
With Interview (+14.0%)
2y 3m
Median Time to Grant
High
PTA Risk
Based on 824 resolved cases by this examiner. Grant probability derived from career allow rate.

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