Prosecution Insights
Last updated: April 19, 2026
Application No. 18/730,396

Oil-Free Air Compressor

Non-Final OA §103
Filed
Jul 19, 2024
Examiner
MIAN, SHAFIQ A
Art Unit
3746
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Hitachi Industrial Equipment Systems Co., Ltd.
OA Round
1 (Non-Final)
79%
Grant Probability
Favorable
1-2
OA Rounds
2y 2m
To Grant
99%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
636 granted / 809 resolved
+8.6% vs TC avg
Strong +26% interview lift
Without
With
+25.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 2m
Avg Prosecution
22 currently pending
Career history
831
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
43.8%
+3.8% vs TC avg
§102
25.0%
-15.0% vs TC avg
§112
27.1%
-12.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 809 resolved cases

Office Action

§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 . Responsive to correspondence This office action is in response to correspondence filed on 07/19/2024. Information Disclosure Statement The information disclosure statement filed 07/19/2024 was filed before the first action on the merits. This submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS has been fully considered by the Office. Abstract The abstract filed 07/19/2024 appears to be acceptable. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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. 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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 non-obviousness. Claim(s) 1-2, 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE). Re: Claim 1: SASAKI discloses: An oil-free air compressor (See Fig.1: ¶0001 discloses oil-free compressor 1) comprising: an oil-free compressor body (See Fig.1: ¶0001 discloses oil-free compressor 1 implicitly comprises a body and as shown in figure 1) that compresses air (See Fig.1: ¶0001: compresses air), and that outputs the compressed air (See Fig.1: ¶0001: compresses air and outputs compressed air); a cooler (See Fig.1: ¶0001: cooler 3) that is connected to the compressor body (See Fig.1: ¶0001 discloses oil-free compressor 1 implicitly comprises a body and as shown in figure 1), and that cools the compressed high-temperature air (See Fig.1: ¶0001 typically cooler cools the compressed air outputted by the compressor 1); a dry air supply mechanism for supplying dry air to an output side of the compressor body (See Fig.1: ¶0001:the oilless air compressor being further provided with an anti-corrosion gas supply means 8 that supplies dry air to the output side of the compressor 1); and SASAKI is silent regarding: a mechanism for preventing a reverse rotation of the compressor body during a shutdown of the compressor. However, KOBE teaches: a mechanism for preventing a reverse rotation of the compressor body during a shutdown of the compressor (See Fig.2: see under description of Fig.2: lines 1-9: discloses a screw compressor wherein, by providing a ratchet mechanism or other mechanical reversal prevention device in the rotor shaft system, a state in which gas on the high-pressure side flows back and expands on the low-pressure side when the compressor stops, causing the rotor to rotate in the opposite direction). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure SASAKI to include the teachings of KOBE, because KOBE teaches that the disclosed configuration provides the benefit for driving a rotor of the screw compressor, a gear device for accelerating or decelerating, or other components. Re: Claim 2: SASAKI modified by KOBE discloses: The oil-free air compressor according to claim 1, modified SASAKI discloses all the limitations of claim 1, and wherein the air compressor according to claim 1 wherein the compressor body is an oil-free screw compressor (SASAKI/KOBE: See Fig.1: discloses oil-free screw compressor). Re: Claim 4: SASAKI modified by KOBE discloses: The oil-free air compressor according to claim 1, modified SASAKI discloses all the limitations of claim 1, and wherein the mechanism for preventing the reverse rotation of the compressor body is a ratchet mechanism (KOBE: discloses ratchet mechanism as explained on page 1 lines 1-4). Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) as applied to claim 1 above, and further in view of JP 2000130528 A5 to JP’528 (JP’528). Re: Claim 3: SASAKI modified by KOBE discloses: The oil-free air compressor according to claim 1 modified SASAKI discloses all the limitations of claim 1, and wherein the mechanism for preventing the reverse rotation of the compressor body is a brake device (KOBE: See page 1 lines 1-4: a mechanical reversal prevention device, and thus can be said to be a braking device, alternatively use of a braking device with the motor is well known in the art, such a braking system is explicitly taught by JP 2000130528 A5 to JP’528 (JP’528), which discloses that, a combination of various well-known techniques such as a combination of a trapezoidal screw and a worm transmitter, a combination of a normal screw or a ball screw and a motor with a brake, and the use of a reverse rotation prevention step motor may be considered, it would have been therefore obvious to one of ordinary skill in the art before the effective filing date of the invention to employ brakes as an alternative to ratchet mechanism where both the device resolves the same problem and would have yielded predictable results). Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) as applied to claim 1 above, and further in view of JP 2013199891 A to TAKAHASHI (TAKAHASHI). Re: Claim 7: SASAKI modified by KOBE discloses: The oil-free air compressor according to claim 1, modified SASAKI discloses all the limitations of claim 1, the modified SASAKI is silent regarding: wherein, further, the dry air supply mechanism supplies the dry air to a suction side of the compressor body. However, TAKAHASHI teaches: wherein, further, the dry air supply mechanism supplies the dry air to a suction side of the compressor body (TAKAHASHI: ¶0025-¶0039: discloses the blower 1A compresses and sends gas such as atmospheric air A from the upstream side to the downstream side by using lift generated by the blades of an impeller, and is classified into a fan, a blower). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure modified SASAKI to include the teachings of TAKAHSHI, because TAKAHASHI teaches that this configuration provides the benefit of compressing and directing the gas such as atmospheric air from the upstream side to the downstream side by using lift generated by the blades of an impeller. Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) and JP 2013199891 A to TAKAHASHI (TAKAHASHI) as applied to claim 7 above, and further in view of JP 5141350 A to TAZAWA (TAZAWA). Re: Claim 8: SASAKI modified by KOBE and TAKAHASHI discloses: The oil-free air compressor according to claim 7, modified SASAKI discloses all the limitations of claim 1, the modified SASAKI is silent regarding: further comprising: an unloader provided on the suction side of the compressor body and having a valve therein for throttling a path of the compressed air , wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the compressor body. However, TAZAWA teaches: further comprising: an unloader provided on the suction side of the compressor body and having a valve therein for throttling a path of the compressed air , and wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the compressor body (TAZAWA: See Fig.2: ¶0029-¶0032: discloses suction side of the compressor body having a valve for throttling air via a valve as explained in cite paragraphs). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure modified SASAKI to include the teachings of TAZAWA, because TAZAWA teaches that this configuration provides the benefit of compressing and directing the gas such as atmospheric air from the upstream side to the downstream side by using lift generated by the blades of an impeller. Claim(s) 9, 10, 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) as applied to claim 1 above, and further in view of JP 5141350 A to TAZAWA (TAZAWA). Re: Claim 9: SASAKI modified by KOBE discloses: An oil-free air compressor modified SASAKI discloses all the limitations of claim 1, and a mechanism for preventing a reverse rotation of the low- pressure stage compressor body during a shutdown of the compressor (See rejection of claim 1 above) the modified SASAKI is silent regarding: comprising: an oil-free low-pressure stage compressor body and an oil-free high-pressure stage compressor body that compress air, and that output the compressed air; an intermediate-stage pipe connecting the low-pressure stage compressor body and the high-pressure stage compressor body; an intercooler that is provided in an intermediate stage, and that cools the compressed high-temperature air; an aftercooler provided on an output side of the high- pressure stage compressor body; a dry air supply mechanism for supplying dry air to the intermediate-stage pipe. However, TAZAWA teaches: an oil-free low-pressure stage compressor body and an oil-free high-pressure stage compressor body that compress air, and that output the compressed air; an intermediate-stage pipe connecting the low-pressure stage compressor body and the high-pressure stage compressor body; an intercooler that is provided in an intermediate stage, and that cools the compressed high-temperature air; an aftercooler provided on an output side of the high- pressure stage compressor body; a dry air supply mechanism for supplying dry air to the intermediate-stage pipe (TAZAWA See Fig.3: ¶0033-¶0035: discloses an oilless air compressor comprising an intermediate-stage compressor body 1 and a final-stage compressor body 2 that compress and output air, intermediate-stage piping that connects the intermediate-stage compressor body 1 and the final-stage compressor body 2, an intercooler 3 in the intermediate stage that cools compressed hot air, and an aftercooler 4 on the output side of the final-stage compressor body 2, the oilless air compressor being further provided with a gas tank 14 that supplies dry air to the intermediate-stage piping). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure modified SASAKI to include the teachings of TAZAWA, because TAZAWA teaches that this configuration provides the benefit of prevent the occurrence of rusting without the occurrence of wear and peel owing to high temperature high speed rotation of a compressor. Re: Claim 10: SASAKI modified by KOBE and TAZAWA discloses: The oil-free air compressor according to claim 9 , modified SASAKI discloses all the limitations of claim 9, and wherein the low-pressure stage compressor body and the high-pressure stage compressor body are oil-free screw compressors (SASAKI: discloses compressors are oil free compressor, as explained in rejection of claim 1). Re: Claim 12: SASAKI modified by KOBE and TAZAWA discloses: The oil-free air compressor according to claim 9, modified SASAKI discloses all the limitation of claim 9, and wherein the mechanism for preventing the reverse rotation of the low-pressure stage compressor body is a ratchet mechanism (KOBE: discloses ratchet mechanism as explained on page 1 lines 1-4). Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) and JP 5141350 A to TAZAWA (TAZAWA) as applied to claim 9 above , and further in view of JP 2000130528 A5 to JP’528 (JP’528). Re: Claim 11: SASAKI modified by KOBE and TAZAWA discloses: The oil-free air compressor according claim 9, modified SASAKI discloses all the limitations of claim 9, modified SASAKI discloses all the limitations of claim 1, and wherein the mechanism for preventing the reverse rotation of the compressor body is a brake device (KOBE: See page 1 lines 1-4: a mechanical reversal prevention device, and thus can be said to be a braking device, alternatively use of a braking device with the motor is well known in the art, such a braking system is explicitly taught by JP 2000130528 A5 to JP’528 (JP’528), which discloses that, a combination of various well-known techniques such as a combination of a trapezoidal screw and a worm transmitter, a combination of a normal screw or a ball screw and a motor with a brake, and the use of a reverse rotation prevention step motor may be considered, it would have been therefore obvious to one of ordinary skill in the art before the effective filing date of the invention to employ brakes as an alternative to ratchet mechanism where both the device resolves the same problem and would have yielded predictable results). Claim(s) 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over JP 04128595 A to SASAKI (SASAKI) in view of Japanese Utility Model Application No. 135425/1977 (Laid-open No. 5460712/1979) (KOBE STEEL, LTD.) 26 April 1979 (1979-04-26) (KOBE) and JP 5141350 A to TAZAWA (TAZAWA) as applied to claim 9 above , and further in view of JP 2013199891 A to TAKAHASHI (TAKAHASHI). Re: Claim 14: SASAKI modified by KOBE and TAZAWA discloses: The oil-free air compressor according to claim 9 wherein, modified Sasaki discloses all the limitations of claim 9, the modified SASAKI is silent regarding:further, the dry air supply mechanism supplies the dry air to a suction side of the low-pressure stage compressor body. However, TAKAHASHI teaches: wherein, further, the dry air supply mechanism supplies the dry air to a suction side of the compressor body (TAKAHASHI: ¶0025-¶0039: discloses the blower 1A compresses and sends gas such as atmospheric air A from the upstream side to the downstream side by using lift generated by the blades of an impeller, and is classified into a fan, a blower). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure modified SASAKI to include the teachings of TAKAHSHI, because TAKAHASHI teaches that this configuration provides the benefit of compressing and directing the gas such as atmospheric air from the upstream side to the downstream side by using lift generated by the blades of an impeller. Re: Claim 15: SASAKI modified by KOBE, TAKAHASHI and TAZAWA discloses: The oil-free air compressor according to claim 14, modified SASAKI discloses all the limitations of claim 14, the modified SASAKI is silent regarding: further comprising: an unloader provided on the suction side of the compressor body and having a valve therein for throttling a path of the compressed air , wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the compressor body. However, TAZAWA teaches: further comprising: an unloader provided on the suction side of the compressor body and having a valve therein for throttling a path of the compressed air , and wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the compressor body (See Fig.2: ¶0029-¶0032: discloses suction side of the compressor body having a valve for throttling air via a valve as explained in cite paragraphs). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure modified SASAKI to include the teachings of TAZAWA, because TAZAWA teaches that this configuration provides the benefit of compressing and directing the gas such as atmospheric air from the upstream side to the downstream side by using lift generated by the blades of an impeller. Allowable Subject Matter Claims 5-6 and 13 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. The following is a statement of reasons for the indication of allowable subject matter: Claims 5 and 13 contains an allowable subject matter because the prior art of record failed to disclose or teach “The oil-free air compressor according to claims 1 and 9 including the limitations of claims 5 and 13 respectively, an oil pump that supplies lubricating oil to each bearing; an opening-closing valve provided on a suction side of the oil pump; and a single motor that drives the compressor body and the oil pump, wherein the oil pump is a gear pump, the motor, the compressor body, and the oil pump are connected to each other by gears, and the opening-closing valve is closed during the shutdown of the compressor” Claim 5 is allowable based on its dependency on allowable claim 5 on allowable claim contains and intervening claims. . Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to SHAFIQ A MIAN whose telephone number is (571)272-4925. The examiner can normally be reached 8:30 am to 6:30 pm (Monday thru Thursday). 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, MARK LAURENZI can be reached at (571) 270-7878. 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. /SHAFIQ MIAN/Primary Examiner, Art Unit 3746 January 28, 2026
Read full office action

Prosecution Timeline

Jul 19, 2024
Application Filed
Jan 28, 2026
Non-Final Rejection — §103 (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
79%
Grant Probability
99%
With Interview (+25.6%)
2y 2m
Median Time to Grant
Low
PTA Risk
Based on 809 resolved cases by this examiner. Grant probability derived from career allow rate.

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