Detailed Action1
America Invents Act Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 USC 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.
Claim Objections
Claim 22 is objected to because of an informality: the word “average” should be inserted before “second wall thickness” in line 2. Appropriate correction is required.
Rejections under 35 USC 112
The following is a quotation of 35 U.S.C. 112:
(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, 5, 7-9, 11-14, and 20-26 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 applicant regards as the invention.
Claim 1 recites the steel alloy reduces thermal conductivity of heat from the combustion chamber through the piston upper part increasing a temperature of the combustion chamber surface and increasing a thermodynamic efficiency of the piston. It is unclear what the steel alloy has to reduce thermal conductivity with respect to. For purposes of examination, the steel alloy merely has to reduce thermal conductivity with respect to other materials that can be used as the piston upper part.
Claim 24 recites about 20 W/m*K. The term “about” renders the claim indefinite. The term “about” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
The rest of the claims are rejected for depending from claim 1 and/or claim 24.
Rejections under 35 USC 1032
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 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious3 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(a) 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.
Claims 1, 5, 7, and 9 are rejected under 35 U.S.C. 103 as being unpatentable over EP-3333277-A1 (“Sidenor”) in view of USPGPub No. 2009/0151555 (“Lapp”).
Claim 1 recites a piston blank for a piston. Sidenor teaches providing pieces of steel which can subsequently be machined or formed into a piston (¶ [0001], [0023], [0057]-[0060] & [0064]), i.e. piston blank. Sidenor further discloses the piston upper part of the piston blank is manufactured from a steel alloy comprising: a chromium content of 0.9 to 1.2 percent by weight; and a silicon content of 2.85 to 3 percent by weight; a carbon content of 0.4 to 0.44 percent by weight; a manganese content of 0.6 to 0.8 percent by weight; and a molybdenum content of 0.15 to 0.2 percent by weight (para. [0028], wherein the ranges in Sidenor overlap with the claimed ranges and disclose the claimed ranges with sufficient specificity; see also Table 1 in ¶ [0066] which teaches a specific steel C that has specific chromium, silicon, carbon, manganese, and molybdenum contents that are within the claimed range or very close thereto). In the alternative, a prima facie case of obviousness is made since the ranges in Sidenor overlap or a very close to the claimed ranges.
Claim 1 also recites the steel alloy reduces thermal conductivity of heat from the combustion chamber through the piston upper part increasing a temperature of the combustion chamber surface and increasing a thermodynamic efficiency of the piston. The steel alloy of Sidenor is capable of reducing thermal conducting of heat through the piston upper part—thus increasing a thermodynamic efficiency of the piston—at least with respect to materials that are more thermally conductive than the steel alloy of Sidenor. One of skill in the art appreciates that some steel alloys have higher thermal conductivity than the steel alloy of Sidenor. One of skill in the art also appreciates that other metal alloys such as certain copper or aluminum alloys have higher thermal conductivities that the steel alloy of Sidenor.
Claim 1 further recites the chromium content and the silicon content increase a resistance to scaling of the combustion chamber surface at the increased temperature of the combustion chamber surface. This limitation is merely discussing the properties of chromium and silicon. Both chromium and silicon are known to resist scaling, thus one of skill in the art will reasonably infer that the chromium and silicon contents in the steel alloy of Sidenor will increase a resistance to scaling at least with respect to certain steel alloys without silicon or chromium. For example, chromium is the primary element responsible for the stainless nature of stainless steel—stainless steel being highly resistant to scaling. Silcon is also frequently added to steel alloys to resist scaling. Sidenor also teaches this (see ¶ [0001], [0024] & [0057] of Sidenor, wherein resisting oxidation also resists scaling since scaling is formed by oxidation).
Sidenor fails to explicitly teach the piston blank having a piston upper part including a combustion chamber bowl having a combustion chamber surface configured to be in communication with a combustion chamber and a piston lower part having a piston shaft defining a pin bore. However, this would have been obvious in view of Lapp.
Lapp is directed to a piston structure (fig. 1, ¶ [0001]), specifically a piston to minimize the amount of oil that escapes from the cooling gallery into the combustion chamber (¶ [0005]). Lapp teaches the piston having an upper part 22 including a combustion chamber bowl 30 having a surface configured to be in communication with a combustion chamber, and a piston lower part 24 having a shaft 76 that defines a pin bore 46 (fig. 1, ¶ [0021] & [0027]). Lapp teaches that the upper and lower parts 22 & 24 can be initially separate and connected together, or, the upper and lower parts 22 & 24 can be a unitary, one-piece design (¶ [0024]). The upper and lower parts can both be formed from a steel material (¶ [0024]). One of skill in the art will reasonably infer that the one-piece design is formed of the same steel material throughout since different materials are not fixed together.
In this case, Sidenor teaches a steel material used in a piston and capable of being forged, but is silent as to a specific piston structure. Lapp teaches a specific piston structure to minimize oil leakage. Since the piston upper part is subjected to the highest temperatures and pressures, it is predictable that using the steel of Sidenor to create at least the upper part of the piston of Lapp will take advantage of the Sidenor steel benefits such as high resistance to oxidation and good mechanical strength at high temperature. Thus, it would be obvious to use the steel of Sidenor to create at least the upper part of the piston of Lapp.
Regarding claim 5, Sidenor further teaches the steel alloy comprises a titanium content of 0.005 to 0.015 percent by weight (¶ [0046]).
Claim 7 recites the increased resistance to scaling is at the increased temperature of the combustion chamber surface of 550 to 650 °C. As detailed in the rejection to claim 1, above, the combustion chamber surface is formed out of the steel alloy of Sidenor that resists oxidation and scaling as also detailed in the rejection to claim 1 (see also ¶ [0024] & [0057] of Sidenor).
Claim 9 recites the piston blank is an integral component made from the steel alloy throughout. As detailed in the rejection to claim 1, above, Lapp teaches forming the whole piston as a unitary, one-piece design (¶ [0024]). One of skill in the art will reasonably infer that the one-piece design is formed of the same steel alloy throughout since different materials are not fixed together. Thus, in order to form a piston with high resistance to oxidation and good mechanical strength at high temperature, it would be obvious to use the steel of Sidenor to create the unitary, one-piece piston taught by Lapp so that the entire piston is made from the steel alloy of Sidenor.
Allowable Subject Matter
Claims 8, 11-14, and 20-26 would be allowable if rewritten to overcome the rejections under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include 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: the prior art fails to teach or fairly suggest the piston upper part and lower part, wherein the lower part is made from a steel material having a higher thermal conductive than the steel alloy of the upper part, and wherein the upper part comprising a steel alloy having the composition of claim 1, in combination with the other limitations of claims 1 and 8. USPGPub No. 2011/0030645 (“Rebello”) teaches that it is known for a steel upper part to have a lower thermal conductivity than a steel lower part. However, Rebello teaches the steel upper part being a stainless steel. Further, the art teaches one of skill in the art that to provide a reduction in thermal conductivity of the piston upper part with respect to a piston lower part, a stainless steel should be used (see e.g. Rebello & 20120180749) or a coating is formed on the upper part (see e.g. 20210180538, 20210102511, 20180094603, 20170241371 & 20120180749). It is also unclear what the thermal conductivity of the steel alloy of Sidenor is (as detailed more in the response to argument section below). Thus, it is not obvious without hindsight to form claim 8.
Response to Arguments
Applicant's arguments filed May 12, 2026 (“the remarks”) have been fully considered. These arguments are moot as a new ground of rejection is made herein. However, the examiner will address one argument as it could be relevant to other rejections.
Applicant argues that it is not obvious to combine Sidenor with Kemnitz because the claimed steel alloy has a lower thermal conductivity, while Kemnitz promotes heat transfer away from the combustion bowl.
This argument is not persuasive because as stated on paragraph 10 of the Affidavit filed on May 12, 2026, the co-inventor states that the reduction in thermal conductivity was unexpected. Thus, based on these arguments, it appears one of skill in the art (before the instant application was filed) would not have known that the steel alloy of Sidenor would reduce thermal conductivity.
Conclusion
Applicant's amendment necessitated the new grounds 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 extension fee 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 date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Kyle Cook whose telephone number is 571-272-2281. The examiner’s fax number is 571-273-3545. The examiner can normally be reached on Monday-Friday 9AM-5PM EST.
If attempts to reach the examiner by telephone are unsuccessful, please contact the examiner's supervisor Thomas Hong (571-272-0993). The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/KYLE A COOK/Primary Examiner, Art Unit 3726
1 The following conventions are used in this office action. All direct quotations from claims are presented in italics. All information within non-italicized parentheses and presented with claim language are from or refer to the cited prior art reference unless explicitly stated otherwise.
2 In 103 rejections, when the primary reference is followed by “et al.”, “et al.” refers to the secondary references. For example, if Jones was modified by Smith and Johnson, subsequent recitations of “Jones et al.” mean “Jones in view of Smith and Johnson”.
3 Hereafter all uses of the word “obvious” should be construed to mean “obvious to one of ordinary skill in the art before the effective filing date of the claimed invention.”
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