Prosecution Insights
Last updated: April 19, 2026
Application No. 18/502,518

BRAKE SYSTEMS WITH A PLURALITY OF SINGLE-CHAMBER MASTER CYLINDERS

Non-Final OA §103§112
Filed
Nov 06, 2023
Examiner
MORRIS, DAVID R.
Art Unit
3616
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
ZF Active Safety US Inc.
OA Round
1 (Non-Final)
82%
Grant Probability
Favorable
1-2
OA Rounds
2y 2m
To Grant
96%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
417 granted / 508 resolved
+30.1% vs TC avg
Moderate +14% lift
Without
With
+13.7%
Interview Lift
resolved cases with interview
Fast prosecutor
2y 2m
Avg Prosecution
37 currently pending
Career history
545
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
31.8%
-8.2% vs TC avg
§102
35.0%
-5.0% vs TC avg
§112
29.9%
-10.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 508 resolved cases

Office Action

§103 §112
DETAILED CORRESPONDENCE 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) has been considered. Drawings The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference character “136” has been used to designate both a return line and an electric motor (see pgh. 0030). Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance. Claim Objections The following claims are objected to because of the following informalities: Claim 1 recites, “the first and second MC outlets” in lines 12-13, where previously recited was first and second “outputs”. Please amend this clause for consistency with the rest of the claims. Appropriate correction is required. 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. Claims 1-16 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 pre-AIA the applicant regards as the invention. Claim 1 recites, “at least one brake pressure signal” in line 19. Previously recited in line 17 was “a brake pressure signal”. It is unclear if this is the same signal as previously recited or a separate signal. Claim 1 recites, “a normal non-failure braking mode” in line 22, previously recited in line 5. It is unclear if this is the same mode as previously recited or a separate mode. Claim 7 recites, “the motor-driven master cylinder is a single-chamber master cylinder”. Previously recited in claim 1 was “first and second motor-driven master cylinders”. It is unclear if claim 7 requires only 1 of the first and second master cylinders to be single chamber, or if both are required to be single chamber. Claim 8 recites, “at least one brake pressure signal”, previously recited in claim 1. It is unclear if this is the same signal as previously recited or a separate signal. Claim 9 recites, “at least one brake pressure signal” twice, previously recited in claim 8 and 1. It is unclear if this is the same signal as previously recited or a separate signal. It is further unclear if the two recited instances in claim 1 are two separate signals or the same signal. Dependent claims not specifically mentioned are rejected due to dependency on a rejected base claim for failing to cure the deficiencies of the base claim. 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. 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 1-5, 7 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Drotleff et al. (U.S. 2021/0031742) in view of Kim (U.S. 2022/0176928). Regarding claim 1, Drotleff discloses (fig. 1) A brake system for actuating a plurality of wheel brakes (5-8) comprising first and second pairs of wheel brakes (first pair 5-6, second pair 7-8), the system comprising: a reservoir (2); first and second motor-driven master cylinders (9,10), each master cylinder being operable during a normal non-failure braking mode (see pgh. 0033) by actuation of an electric MC drive motor (11,12) of the master cylinder to generate brake actuating pressure at a respective first or second MC output (respective downstream fluid lines from 9,10) for hydraulically actuating a corresponding one of the first and second pairs of wheel brakes (9 actuates 5-6 and 10 actuates 7-8); a first traction control iso valve (14) hydraulically interposed between the first master cylinder and the first pair of wheel brakes via the first MC outlet; a second traction control iso valve (15) hydraulically interposed between the second master cylinder and the second pair of wheel brakes via the second MC outlet; at least two brake pressure sensors (each of boxes “P/U” at each output of 9,10 respectively), each brake pressure sensor being associated with a selected one of the first and second pairs of wheel brakes (“associated” as shown) for sensing hydraulic pressure at the corresponding pair of wheel brakes (the brake pressure exiting 9,10 is communicated to the wheels, thus this pressure sensor is “for sensing hydraulic pressure at the corresponding pair of wheel brakes”) and responsively producing a brake pressure signal (the sensors produce a signal indicative of brake pressure, thus this is a “brake pressure signal”); an electronic control unit (each of 27,28) for controlling at least one of the first and second master cylinders responsive to at least one brake pressure signal (see pgh. 0034 at least, further they are capable of adjusting the pressure “responsive to at least one brake pressure signal”, which corresponds to the pedal actuation at least); and a secondary power transmission unit (23-25) configured for selectively providing pressurized hydraulic fluid at first and second PTU outputs (see fluid lines connected to 23,24) for actuating the first and second pairs of wheel brakes in at least one of a normal non-failure braking mode and a backup braking mode (for the backup mode at least), the secondary power transmission unit including an electric PTU motor (25) configured to selectively pressurize the hydraulic fluid by transmitting rotary motion to at least two pump pistons (23,24), each pump piston providing pressurized hydraulic fluid to a corresponding one of the first and second PTU outputs (23 to the left output, 24 to the right output), each of the first and second PTU outputs providing fluid to a corresponding one of the first and second pairs of wheel brakes (as shown); Drotleff does not appear to disclose the secondary power transmission unit being directly fluidly connected to the reservoir. In the same field of endeavor of vehicle brake systems, Kim teaches (fig. 1) a brake system (1000) with secondary power transmission unit (1610,1620), wherein the secondary power transmission unit is directly fluidly connected to the reservoir (via line 1641, connected directly to the reservoir 1200). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have added a direct fluid line connection from the secondary power transmission unit to the reservoir as suggested by Kim to ensure adequate accumulator utilization, adequate supplemental brake pressure under a prolonged backup mode, and protecting against loss of pressure due to system leakage. Under a prolonged backup mode, the accumulators may empty and then the system is unable to provide the necessary pressure for braking, so having a connection line to the reservoir allows the pumps to pull more fluid into the system for braking. Additionally, the accumulator may wear or leak over time, thus reducing the pressure during a backup mode, so the system would be able to pull fluid directly from the reservoir as needed. Regarding claim 2, Drotleff discloses a deceleration signal transmitter (brake pedal 33 at least) configured to provide a braking signal, in a wired or wireless manner, corresponding to a desired braking action by an operator of the vehicle, wherein the electronic control unit controls at least one of the first and second master cylinders responsive to the braking signal (see pgh. 0034 at least). Regarding claim 3, while Drotleff discloses dump valves, it does not appear to disclose iso valves for each wheel. Kim teaches (fig. 1) an iso/dump control valve arrangement (valves of 1510,1520) associated with each wheel brake of the plurality of wheel brakes (one ISO 1511a-d and one dump 1512a-d for each wheel), each iso/dump control valve arrangement being controlled by the electronic control unit (see pgh. 0068 at least). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have provided iso and dump valves to each wheel, and have these valves controllable by the electronic control unit to provide ABS functionality at each wheel, as desired (see pgh. 0067-0068 at least). Regarding claim 4, Drotleff as modified teaches wherein each iso/dump control valve arrangement is in fluid communication with both a selected one of the first and second MC outputs and a selected one of the first and second PTU outputs (first two pairs of valves associated with one of the outputs and second two pairs of valves associated with the other. The first and second MC outputs are already “associated with” one of the first and second PTU outputs respectively) for selectively receiving pressurized hydraulic fluid therefrom (as modified). Regarding claim 5, Drotleff as modified teaches the first traction control iso valve is hydraulically interposed between the first master cylinder and the iso/dump control valve arrangements of the first pair of wheel brakes, and wherein the second traction control iso valve is hydraulically interposed between the second master cylinder and the iso/dump control valve arrangements of the second pair of wheel brakes (as modified, iso valves 1511 are upstream from the dump valves 1512, and the master cylinders 9,10 of Drotleff is upstream of everything else). Regarding claim 7, Drotleff as modified teaches the motor-driven master cylinder is a single-chamber master cylinder (fig. 1 as shown). Regarding claim 12, Drotleff as modified teaches each of the first and second MC outputs is in fluid communication, via a corresponding first or second traction control iso valve (when valves 14 and 18 are open and valves 15 and 19 are open, for example), with a pump input of at least one pump piston (bottom line of 23,24) for selectively supplying pressurized hydraulic fluid thereto, the secondary power transmission unit selectively boosting pressure of the pressurized hydraulic fluid (as described) to supply boosted-pressure hydraulic fluid to at least one of the first and second PTU outputs in at least one of a normal non-failure braking mode and a backup braking mode (backup mode at least). Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Drotleff et al. (U.S. 2021/0031742) in view of Kim (U.S. 2022/0176928) Takimoto et al. (U.S. 2022/0055582). Regarding claim 6, Drotleff does not appear to disclose the pressure sensor location. Takimoto teaches (fig. 1) brake pressure sensors (92S, 92P) is interposed hydraulically between a corresponding first or second traction control iso valve (21S,21P) and a respective iso/dump control valve arrangement (25a-d and 28a-d). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have provided the pressure sensors at the recited location as suggested by Takimoto to detect wheel pressure when the traction control iso valves are closed, thereby ensuring correct pressure supply for braking. Claims 8-9 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Drotleff et al. (U.S. 2021/0031742) in view of Kim (U.S. 2022/0176928) and Ganzel (U.S. 2019/0092304). Regarding claim 8, Drotleff as modified teaches the electronic control unit is a first electronic control unit controlling at least one of the first and second master cylinders (27 controls 9). Drotleff does not appear to disclose a second electronic control unit controlling the secondary power transmission unit. Ganzel teaches a brake system (10) including a first control unit (40) controlling the majority of the valves, master cylinder 34, etc., and a second electronic control unit (42) controlling the secondary power transmission unit (18), wherein both the first and second electronic control units control the respective first and/or second master cylinder (34) and secondary power transmission unit (18) responsive to at least one brake pressure signal (normal operation thereof). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have provided a separate ECU for the secondary power transmission unit of Drotleff as suggested by Ganzel to reduce system cost (see pgh. 0023 Ganzel). Regarding claim 9, Drotleff as modified further teaches a third electronic control unit (28), wherein the first electronic control unit controls a chosen one of the first and second master cylinders responsive to at least one brake pressure signal (27 controls 9) and the third electronic control unit controls an other one of the first and second master cylinders responsive to at least one brake pressure signal (28 controls 10). Regarding claim 13, Drotleff as modified does not appear to disclose which components are disposed in which housings. Ganzel further teaches (fig. 1) the reservoir (36) and master cylinder are co-located in a first housing (12) and the secondary power transmission unit (18) is located in a second housing (14), spaced apart from the first housing (pgh. 19, 14 and 18 can be “located remotely” from the main housing 12). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have provided separate housings for the reservoir and master cylinders and the secondary power transmission unit to provide modularity in the system, such that some customers can be sold a simpler brake system, but other customers can have a feature enhanced system with the secondary power transmission unit (see pgh. 0019). Allowable Subject Matter Claims 10, 11, and 14-16 would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims, and if rewritten to overcome any 112(b) rejections, as appropriate. Reasons for allowance, if applicable, will be the subject of a separate communication to the Applicant or patent owner, pursuant to 37 CFR § 1.104 and MPEP § 1302.14. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID MORRIS whose telephone number is (571)270-3595. The examiner can normally be reached Monday thru Friday; 8:30 AM - 5:00 PM. 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, Robert Siconolfi can be reached at (571) 272-7124. 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. /DAVID MORRIS/ Primary Examiner Art Unit 3616 /DAVID R MORRIS/Primary Examiner, Art Unit 3616
Read full office action

Prosecution Timeline

Nov 06, 2023
Application Filed
Jan 21, 2026
Non-Final Rejection — §103, §112 (current)

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

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Prosecution Projections

1-2
Expected OA Rounds
82%
Grant Probability
96%
With Interview (+13.7%)
2y 2m
Median Time to Grant
Low
PTA Risk
Based on 508 resolved cases by this examiner. Grant probability derived from career allow rate.

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