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 .
Response to Arguments
Applicant’s amendments to the claims overcomes the objection raised in the office action dated 10/01/2025.
Applicant's arguments filed 03/31/2026 pertaining to the prior art rejections have been fully considered but they are not persuasive.
Applicant's remarks state that Wienecke does not explicitly discuss "balanced flow paths" and therefore should not be interpreted to be balanced flow paths. However, the term "balanced flow paths" appears to be broad enough to encompass symmetrical flow paths and appears to be consistent with applicant's drawings and disclosure. Further, applicant's claims do not specify what is required with the limitation "effectively balanced flow paths". While the flow paths 38 and 40 may not inherently be balanced flow paths, they appear to be implicitly balanced flow paths because they are shown to be symmetrical and without valve obstructions, therefore one of ordinary skill in the art would reasonably recognize that they are "effectively balanced flow paths" in a manner consistent with applicant's disclosure.
Applicant's remarks discuss reservoir 48 causing unbalanced flow paths, however, this reservoir is not required to be connected to either line 38 or line 40. When both loaded check valves are closed, it is reasonable to believe that lines 38 and 40 would not have different flow characteristics and would be “effectively balanced flow paths”.
Applicant's remarks state that the reliance on the schematic depiction of hydraulic lines 38 and 40 to assert balanced flow paths is not the proper standard for interpreting a reference and points to states that drawings are not to scale. However the MPEP also states that:
"The drawings must be evaluated for what they reasonably disclose and suggest to one of ordinary skill in the art. In re Aslanian, 590 F.2d 911, 200 USPQ 500 (CCPA 1979). See MPEP § 2121.04 for more information on prior art drawings as "enabled disclosures.""
One of ordinary skill in the art would reasonably understood from the symmetrical hydraulic lines that do not include valves on the main conduits between the pump and the hydraulic actuator to have equivalent flow characteristics and would be balanced in a manner consistent with applicant’s disclosure especially in light of the similarities between applicant’s Figures and the prior art Figures.
Since Wienecke remains silent as to this balanced flow path feature, examiner relies upon the drawings which show a configuration nearly identical to applicant's drawings with regards to the buffer and the main flow paths between the hydraulic machine and hydraulic pump, therefore, it is reasonable to assert that they would function the same when the extra valves of Wienecke are closed. There is no indication that fluid from the reservoir must provide fluid to either main flow path 38, 40 at all times because the fluid chambers and flow paths and fluid chambers of the actuator are symmetrical and make-up flow from the reservoir is not required. Fluid would simply flow from one chamber to the other through the bidirectional pump. The spring loaded check valves would not open unless the biasing force of the springs is overcome and this would only happen in limited circumstances.
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.
Claim(s) 1, 3, 6-7, 9-15, 18-19, and 21-25, 33, 34 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wienecke (DE 102008013593).
Wienecke renders obvious:
1. (Currently Amended) A hydraulic system comprising: a hydraulic device (24) with a first device port (25) and a second device port (26); a differential buffer (Fig. 6, 50) with a first buffer port (apparent from Fig. 6) and a second buffer port (apparent from Fig. 6); a first flow path (38) that fluidly connects the first device port to the first buffer port; and a second flow path (40) that fluidly connects the second device port with the second buffer port; wherein, in at least a first mode of operation, the first device port is a device inlet port and the second device port is a device outlet port (24 is a bidirectional pump that can reverse its inlets and outlets, see paragraph [0024]), wherein the differential buffer includes a first buffer chamber 42 and a second buffer chamber 44 that are fluidly separated by a buffer piston 56 slidably received in the differential buffer, wherein the first buffer chamber is fluidly connected to the first buffer port and the second buffer chamber is fluidly connected to the second buffer port (apparent from Fig. 6), and wherein the buffer piston is configured to oscillate and is biased towards a neutral position (paragraph [0038] discloses piston 56 urged to a piston center position by springs 48), and wherein the first flow path and the second flow path are effectively balanced flow paths (flow paths 38 and 40 are balanced in an analogous manner as applicants device, having no other valves or structures in the first and second flow paths as claimed;
while the flow paths 38 and 40 may not inherently be balanced flow paths, they appear to be implicitly balanced flow paths because they are shown to be symmetrical and without valve obstructions, therefore one of ordinary skill in the art would reasonably recognize that they are "effectively balanced flow paths" in a manner consistent with applicant's disclosure;
since Wienecke remains silent as to this balanced flow path feature, examiner relies upon the drawings which show a configuration nearly identical to applicant's drawings with regards to the buffer and the main flow paths between the hydraulic machine and hydraulic pump, therefore, it is reasonable to assert that they would function the same when the extra valves of Wienecke are closed. There is no indication that fluid from the reservoir must provide fluid to either main flow path 38, 40 at all times because the fluid chambers and flow paths and fluid chambers of the actuator are symmetrical and make-up flow from the reservoir is not required. Fluid would simply flow from one chamber to the other through the bidirectional pump. The spring loaded check valves would not open unless the biasing force of the springs is overcome and this would only happen in limited circumstances).
3. (Currently Amended) The system of claim 1, further comprising a first spring configured to resist motion of the buffer piston in a first direction and a second spring configured to resist motion of the buffer piston in a second direction opposite the first direction (see Fig. 6, springs 58).
6. (Currently Amended) The system of claim 3, wherein the buffer piston is configured to move in the first direction when a pressure in the first buffer chamber is greater than a pressure in the second buffer chamber and in the second direction, opposite the first direction, when the pressure in the second buffer chamber is greater than the pressure in the first buffer chamber (apparent from the Figures, see paragraph [0029], etc.).
7. (Original) The system of claim 6, wherein when the buffer piston moves in the first direction a first volume of the first buffer chamber expands and a second volume of the second buffer chamber contracts, and wherein when the buffer piston moves in the second direction opposite the first direction, the second volume of the second buffer chamber expands and the first volume of the first buffer chamber contracts (apparent from the Figures, see paragraph [0029], etc.).
9. (Previously Presented) The system of claim 3, wherein the hydraulic device is selected from the group consisting of a hydraulic pump and a hydraulic motor (24 is a hydraulic pump)
10. (Previously Presented) The system of claim 3, wherein the first flow path has a first compliance and the second flow path has a second compliance, and wherein the first compliance is within 20% of the second compliance within a predetermined frequency range (this limitation is implicitly disclosed since the first and second flow paths 38, 40 are symmetrical/identical, the net compliances of both flow paths are expected to be similar or identical, which is within 20% of each other, similar to applicant’s device).
11. (Previously Presented) The system of claim 3, wherein the first fluid flow path has a first impedance and the second fluid flow path has a second impedance, and wherein the first impedance is within 20% of the second impedance within a predetermined frequency range (this limitation is implicitly disclosed since the first and second flow paths 38, 40 are symmetrical/identical, the impedances of both flow paths are expected to be similar or identical, which is within 20% of each other, similar to applicant’s device).
12. (Previously Presented) The system of claim 3, wherein the differential buffer includes a third port and a fourth port, and wherein the third and fourth ports are in fluid communication with a hydraulic load (apparent from Fig. 2 and Fig. 6).
13. (Original) The system of claim 12, wherein the hydraulic load is an active suspension actuator (absent further limitations pertaining to what an “active suspension actuator” requires, the actuator 27 of Wienecke will be interpreted to be meet active suspension actuator limitation since applicant’s disclosed “active suspension actuator 150” is a hydraulic cylinder similar to Wienecke’s hydraulic cylinder 27, and both actuators function similarly by extending and retracting using fluid pressure).
14. (Currently Amended) An active suspension actuator system, comprising: a hydraulic device including a first device port and a second device port; a differential buffer with a first buffer chamber and a second buffer chamber that are fluidly separated by a buffer piston slidably received in the differential buffer, wherein the buffer piston is configured to oscillate and is biased towards a neutral position, wherein the first buffer chamber is fluidly connected to the first port of the hydraulic device through a first flow path and the second buffer chamber is fluidly connected to the second port of the hydraulic device through a second flow path, wherein, in at least a first mode of operation, the first device port is a device inlet port and the second device port is a device outlet port, and wherein the first flow path and the second flow path are effectively balanced flow paths; and a hydraulic actuator with a first actuator chamber and a second actuator chamber that are fluidly separated by an actuator piston slidably received in the hydraulic actuator, wherein the first actuator chamber is fluidly connected to the first buffer chamber and the second actuator chamber is fluidly connected to the second buffer chamber (see claim 1 and 14 rejection for similar claim limitation mapping and discussion, all limitations are either discussed or apparent from Wienecke’s figures).
15. (Original) The system of claim 14, further comprising a first spring configured to resist motion of the buffer piston in a first direction and a second spring configured to resist motion of the buffer piston in a second direction opposite the first direction (see claim 3 rejection for similar limitation mapping and discussion).
18. (Previously Presented) The system of claim 15, wherein the buffer piston is configured to move in a first direction when a pressure in the first buffer chamber is greater than a pressure in the second buffer chamber and in a second direction, opposite the first direction, when the pressure in the second buffer chamber is greater than the pressure in the first buffer chamber (see claim 6 rejection for similar claim limitation mapping and discussion).
19. (Original) The system of claim 18, wherein when the buffer piston moves in the first direction a first volume of the first buffer chamber expands and a second volume of the second buffer chamber contracts, and wherein when the buffer piston moves in the second direction opposite the first direction, the second volume of the second buffer chamber expands and the first volume of the first buffer chamber contracts (see claim 7 rejection for similar claim limitation mapping and discussion).
21. (Previously Presented) The system of claim 14, wherein the hydraulic device is selected from the group consisting of a hydraulic pump and a hydraulic motor (see claim 9 rejection for similar claim limitation mapping and discussion).
22. (Previously Presented) The system of claim 14, wherein a first flow path extending between and including the first device port and the first buffer chamber has a first compliance and a second flow path extending between and including the second device port and the second buffer chamber has a second compliance, and wherein the first compliance is within 20% of the second compliance within a predetermined frequency range (see claim 10 rejection for similar claim limitation mapping and discussion).
23. (Previously Presented) The system of claim 14, wherein a first flow path extending between and including the first device port and the first buffer chamber has a first impedance and a second flow path extending between and including the second device port and the second buffer chamber has a second impedance, and wherein the first impedance is within 20% of the second impedance within a predetermined frequency range (see claim 11 rejection for similar claim limitation mapping and discussion).
24. (Currently Amended) The system of claim 14, wherein the differential buffer includes a third port fluidly coupled to the first buffer chamber and a fourth port fluidly coupled to the second buffer chamber, and wherein the third port of the differential buffer is fluidly connected to the first actuator chamber and the fourth port is fluidly connected to the second actuator chamber (see claim 12 rejection for similar claim limitation mapping and discussion).
25. (Currently Amended) A method of mitigating flow pulsations in a hydraulic system with a differential buffer, the method comprising: applying flow pulsations from a first port of a hydraulic device to a first flow path fluidly connected to a first buffer chamber of the differential buffer and applying flow pulsations from a second port of the hydraulic device to a second flow path fluidly connected to a second buffer chamber of the differential buffer, wherein the first flow path and the second flow path are balanced flow paths (absent further limitations on what is required from a “balanced flow path”, the identical flow paths Wienecke meets the limitation in a manner consistent with applicant’s disclosure as seen in applicant’s drawings), wherein the flow pulsations at the first port are superimposed on a nominal flow at the first port and the pulsations at the second port are super imposed on a nominal flow at the second port, wherein the first flow path and the second flow path are effectively balanced, wherein the flow pulsations in the first buffer chamber are effectively equal in magnitude and at least partially out of phase with the flow pulsations in the second buffer chamber, and wherein in at least one mode of operation the first port of the hydraulic device is an outlet port and the second port of the hydraulic device is an inlet port; and displacing a buffer piston disposed between the first buffer chamber and the second buffer chamber due at least in part to a phase difference between the flow pulsations in the first and second buffer chambers, wherein displacing the buffer piston includes oscillating the buffer piston and biasing the buffer piston towards a neutral position, and as a result of the displacement, at least partially canceling the flow pulsations in the first buffer chamber and the second buffer chamber (see previous claim rejections for similar claim limitation mapping and discussion, while Wienecke does not explicitly disclose the pulsations and the oscillation of the buffer, applicant’s claimed system appear to be the same as Wienecke’s system, therefore it is expected that both systems would operate in the same manner with the same functions and results, which includes wherein the flow pulsations at the first port are superimposed on a nominal flow at the first port and the pulsations at the second port are super imposed on a nominal flow at the second port, wherein displacing the buffer piston includes oscillating the buffer piston and biasing the buffer piston towards a neutral position, and as a result of the displacement, at least partially canceling the flow pulsations in the first buffer chamber and the second buffer chamber, due to the effectively balanced flow paths and the nature of a reversible hydraulic motor,
it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have either recognized or modified the device of Wienecke to have used any suitable hydraulic motor embodiment that has reciprocating pistons that would cause the suction of fluid from one port and pressurized output of fluid flow from the second port which would result in pulsations in the system, and due to the structural configuration of the system of Wienecke, would operate in the same manner as claimed in claim 25).
33. (Previously Presented) The method of claim 25, wherein the hydraulic device is selected from the group consisting of a hydraulic pump and a hydraulic motor (24 is a hydraulic pump).
34. (Previously Presented) The method of claim 25, wherein the phase difference of the hydraulic flow pulsations on each side of the buffer piston are between or equal to 140 degrees and 220 degrees out of phase (see previous claim rejections for similar claim limitation mapping and discussion, according to applicant’s specification, having low difference in impedance and compliance of both flow paths results in a phase difference around 180 degrees, since the flow paths are symmetrical, they are expected to have equivalent compliance and impedance and therefore also have a phase difference around 180 degrees, since prior art hydraulic circuit configuration is similar to the claimed invention, it is expected that they would function similar with regards to the pulsation phases).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Lerner et al. (US 10871174) discloses a hydraulic system using balanced flow within bidirectional power units
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Dustin T Nguyen whose telephone number is (571)270-0163. The examiner can normally be reached M - F: 8:00am - 4:30pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Nathaniel E. Wiehe can be reached at (571) 272-8648. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DUSTIN T NGUYEN/Primary Examiner, Art Unit 3745 May 14, 2026
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