DETAILED ACTION
Examiner’s Note
This office action is in response to applicants’ remarks and amendments to the claims filed October 17 2025. Claims 1, 6-7, 12, 17, and 22-23 are pending with claims 1 and 6-7 remaining withdrawn as directed to non-elected subject matter.
Claim Rejections - 35 USC § 103
The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made.
Claims 12, 17, 22, and 23 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Polen et al. (US PGPub 2007/0102493), in view of Guston (The Cambridge Aerospace Dictionary, second Edition 2009), Navpers (Handbook of Damage Control, 1945), Poli (Design for Manufacturing: A Structured Approach, 2001) and Smith (US PGPub US 2005/0284045), in view of Alessi et al. (PGPub US 2008/0308611) in view of Boyer et al. (Materials Properties Handbook: Titanium Alloys, 1994).
Regarding applicants’ claims 12, Polen et al. disclose a hot stretched workpiece which in one aspect may be titanium, where the workpiece may include two side walls and be imparted with a curvilinear configuration (paragraphs 0001, 0010, 0046, 0047, 0053 and figures 1, 5, and 10).
Polen et al. do not appear to explicitly disclose the addition of a reinforcing member. However, gussets are known reinforcing members for joints and angles in the form of small flat members (Gunston). Navpers disclose an angle clip which can be made much stronger by welding of a triangular bracket (figure 36-79 and page 215). Poli disclose the use of gussets in injection molding as a means of providing stiffening (page 89 section 5.6.3 and figure 5.18). Smith disclose a lintel system including an angle iron provided with a stiffener in the form of triangular members attached at approximately 90°relative to the legs of the angle iron (paragraph 0002, 0057, 0058, and figure 3). One of ordinary skill in the art at the time of the invention would have found it obvious to attach a stiffener/gusset to the work piece of Polen et al. to improve the strength of the work piece.
With regards to the selection of the material for the reinforcing member, it is within the ordinary level of skill in the art to select materials based on known engineering design considerations. One of ordinary skill in the art would have found it obvious to select a material in order to achieve a suitable combination of design parameters including the use of the same material (e.g. a titanium workpiece with a titanium reinforcing member), such that the reinforcing member has the same properties as the workpiece thereby preventing the introduction of stress as the result of using materials with different physical properties e.g. differences in thermal expansion properties, and additionally avoiding challenges in joining of dissimilar materials. Further it is within the ordinary skill in the art to select a material based on its suitability for its intended purpose (MPEP 2144.07). Polen et al. disclose the use of titanium in the manufacture of the hot stretched workpiece, one of ordinary skill in the art would have found it obvious to select titanium for a reinforcing component where titanium is recognized by Polen et al. as a suitable material for the construction of the workpiece.
Polen et al. do not appear to explicitly disclose the process by which the stiffener is attached, however Alessi et al. disclose a linear friction welding method where it has been shown that welds produced by linear friction welding are structurally sound and of high quality, and can be successfully used with materials such as titanium that cannot be easily welded by conventional means (paragraphs 0006). Alessi et al. further teach that linear friction welding involves a solid-state process that results in desirable microstructures thereby producing minimal component distortion and high strength welds (paragraph 0004). One of ordinary skill in the art at the time of the invention would have found it obvious to use the linear friction welding process of Alessi et al. to attach a gusset in order to provide a stiffener which is attached in a manner which is structurally sound and of high quality with minimal distortion of the components being welded.
Additionally the requirements of hot-stretch forming and linear friction welding are process limitations used to define the claimed product. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior art product was made by a different process. Further, the burden shifts to applicant to come forward with evidence establishing an unobvious difference between the claimed product and the prior art product. See MPEP 2113.
Applicants require at least one linear-friction weld joint “defining a weld interface with substantially no residual stress having a severely deformed by highly defined grain structure”. Applicants’ specification at paragraph 0036 states that “Linear friction welding creates a severely deformed, but highly refined grain structures at the weld interface with substantially no residual stress”. The use of linear-friction welding to attach a gusset, as discussed above, would therefore create a severely deformed, but highly refined grain structures with substantially no residual stress. The resulting structure is a reinforcing member positioned at least partially within the space between the sidewalls after the base member of the structural component has been formed.
Further, Polen et al. do not appear to explicitly disclose the workpiece to have substantially no residual stress and further having “portions of the at least two sidewalls of the base member to which the at least on reinforcing member is linear friction welded and which comprises the weld interface” to have essentially no residual stress per (I) and/or (II) as claimed. However, Polen et al. as modified above and applicants, both disclose substantially identical processes, including the use of a hot-stretch forming and linear friction welding. Given the use of substantially identical processes, the resulting workpiece would be expected to have substantially identical properties as those disclosed by applicants, including having substantially no residual stress and satisfying (I) and/or (II) above.
Alternatively, it is known to use heat treatments of titanium to relieve stress from non-uniform hot forging, welding and thermal stresses, without adversely affecting the strength and ductility of the material, the removal of stress helping to maintain shape stability and eliminating unfavorable conditions such as loss of compressive yield strength (page 1111 left column and page 1112 - Stress Relieving – first paragraph). One of ordinary skill in the art at the time of the invention would have found it obvious to subject the workpiece of Polen et al. to a stress relieving heat treatment to relive stress form the hot working and welding operations thereby promoting shape stability and eliminating unfavorable conditions. Given the relief of stress, the product would have substantially no residual stress as presently required.
While applicants expressly claim “without further heat treatments” this is product-by-process requirement which is evaluated with respect to the resulting structure (as discussed above and in MPEP 2113). Here regardless of the use of an additional heat treatment the claimed structure is achieved, i.e. satisfies the requirement of having substantially no residual stress.
Regarding applicants’ claim 17, Polen et al. disclose hot stretch forming of a workpiece as discussed above with respect to claim 12. Applicants’ claim 17 sets forth further limitations defining the product by the apparatus and process used to from the workpiece. Polen et al. do disclose claimed parameters such as a heat insulating enclosure, resistance heating, and moving the profile relative to a die (paragraph 0009-0020), however even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior art product was made by a different process. Further, although produced by a different process, the burden shifts to applicant to come forward with evidence establishing an unobvious difference between the claimed product and the prior art product. See MPEP 2113. Absent a showing that the claimed process and apparatus necessarily results in a structure which is not formed in the prior art, the presently claimed apparatus and process are not found to result in a patentably distinct product.
Regarding applicants’ claims 22 and 23, the term aerospace structural component is broad. Aerospace is a general term used to describe technologies relating to aviation and space flight. A curvilinear workpiece such as disclosed by Polen et al. and modified as described above would have a structure useable as a structural component in an aerospace application. The range of structures in aerospace include but are not limited to, structures related to the manufacture of miniature drones, large cargo aircraft, small satellite rockets, interplanetary probes and rovers, space shuttles, and space stations. Given the range of structures within the field of aerospace, an L shaped reinforced workpiece has the necessary structure to be used as an aerospace structural component.
Response to Arguments
Applicants’ arguments filed October 17, 2025 have been considered but have not been found to be persuasive.
Applicants have amended the claims with regards to include substantially no stress “without further heat treatment”. Applicants argue that there is no reasonable expectation of success in applying linear friction welding to the hot-stretched part of Polen et al. due to the differences in the heat and pressure used. However hot stretching and welding by design are different processes. Alessi et al. disclose the that linear friction welding is a solid-state process of jointing similar or dissimilar metals that results in desirable microstructures in the weld and in the heat affected Zones, producing minimal component distortion and high strength welds. In addition, linear friction welding is also a self-cleaning process, in that the oscillating motion of the process causes surface irregularities and contaminants to be expelled as flash generated during the weld, eliminating production steps (paragraph 0004). MPEP 2143.02 sets forth that “Where there is a reason to modify or combine the prior art to achieve the claimed invention, the claims may be rejected as prima facie obvious provided there is also a reasonable expectation of success. The reasonable expectation of success requirement refers to "the likelihood of success" in combining or modifying prior art disclosures to meet the limitations of the claimed invention.”
Further absolute predictability is not required, “Obviousness does not require absolute predictability, but at least some degree of predictability is required. Evidence showing there was no reasonable expectation of success may support a conclusion of nonobviousness” (MPEP 2143.02). Here Alessi et al. disclose a linear friction welding method where it has been shown that welds produced by linear friction welding are structurally sound and of high quality, and can be successfully used with materials such as titanium that cannot be easily welded by conventional means (paragraphs 0006). One of ordinary skill in the art would have been motivated to select this process, particularly over conventional processes with an expectation of improved results over the use of conventional processes. There is no requirement of complete predictability or that the combination results in the same advantages as may be inherent to later discovered. Here there is motivation to add a reinforcing element and motivation to select liner friction welding as the means by which it is attached as it is demonstrated to produce welds that are structurally sound and of high quality, and can be successfully used with materials such as titanium that cannot be easily welded by conventional means.
With regards to’ without further heating’, the application of linear friction welding as disclosed by Alessi et al. to attach the reinforcement elements to the structural member of Polen et al. do not require further heat treatment. However improvements in the process such as elimination a post processing step are evaluated differently in product claims than they are within process claims. Applicants’ claims are directed to a final product that has substantially no residual stress. It is emphasized that some residual stress may be present and that no specific level of stress is set. The claimed requirement that it occurs “without further heating” when presented in a product claim is evaluated as a product-by-process limitation.
Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process. The structure implied by the process steps should be considered when assessing the patentability of product-by-process claims over the prior art, especially where the product can only be defined by the process steps by which the product is made, or where the manufacturing process steps would be expected to impart distinctive structural characteristics to the final product. MPEP 2113 I.
Here the required feature is a product that has substantially no residual stress. Regardless of if a further heat treatment is carried out the result is the same, a product that is substantially free of residual stress.
Once a product appearing to be substantially identical is found and a prior art rejection is made, the burden of production shifts to applications to demonstrate an non-obvious difference. Once the examiner provides a rationale tending to show that the claimed product appears to be the same or similar to that of the prior art, although produced by a different process, the burden shifts to applicant to come forward with evidence establishing an nonobvious difference between the claimed product and the prior art product. MPEP 2113.
Applicants argue that the results are unexpected and therefore establish non-obviousness however there is insufficient evidence that the application of friction welding to attach a reinforcing element to a hot stretched base member produces unexpected results. In establishing unexpected results “The evidence relied upon should establish "that the differences in results are in fact unexpected and unobvious and of both statistical and practical significance” (MPEP716.02(b)). Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of non-obviousness must be commensurate in scope with the claims which the evidence is offered to support." (MPEP 716.02(d)). There is insufficient evidence presented by applicants to establish that the use of linear friction welding produces a reinforced structural part exhibiting unexpected properties. Absent objective evidence to weight against the teachings of the prior art the preponderance of evidence suggests a reasonable expectation of success with predictable results.
Further while a proposed modification cannot render the prior art unsatisfactory for its intended purpose (MPEP 2143.01 V), there is insufficient evidence such that one of ordinary skill in the art would have concluded that the use of linear friction welding to secure reinforcing elements to the base member of Polen et al. would render the structural member of Polen et al. unsuitable as a structural member.
For these reasons, and for those reasons as provided in the rejections above, the rejections of record are maintained.
Conclusion
THIS ACTION IS MADE FINAL. 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 ADAM C KRUPICKA whose telephone number is (571)270-7086. The examiner can normally be reached Monday-Friday 8-5pm EST.
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/Adam Krupicka/Primary Examiner, Art Unit 1784