Prosecution Insights
Last updated: April 19, 2026
Application No. 17/721,796

BOLT ASSEMBLY

Non-Final OA §103
Filed
Apr 15, 2022
Examiner
WONG, JOCK M
Art Unit
3675
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Rolls-Royce
OA Round
5 (Non-Final)
34%
Grant Probability
At Risk
5-6
OA Rounds
3y 3m
To Grant
78%
With Interview

Examiner Intelligence

Grants only 34% of cases
34%
Career Allow Rate
28 granted / 83 resolved
-18.3% vs TC avg
Strong +45% interview lift
Without
With
+44.6%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
48 currently pending
Career history
131
Total Applications
across all art units

Statute-Specific Performance

§103
48.1%
+8.1% vs TC avg
§102
28.6%
-11.4% vs TC avg
§112
22.6%
-17.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 83 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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 26, 2026 has been entered. Response to Amendment Claim 1 has been amended. Therefore, claims 1-2 and 8-14 remain pending in the application. 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 (i.e., changing from AIA to pre-AIA ) 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. 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) 1-2 and 8-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Reed (US20120219358A1), hereinafter "Reed", in view of Steeljrv (Non-Patent Document U cited in PTO-892 dated December 19, 2024) and RMI Titanium Company, Titanium Alloy Guide (Non-Patent Document V cited in PTO-892 dated July 5, 2024), hereinafter "Steeljrv" and "RMI", respectively. Regarding claim 1, Reed teaches a bolt assembly (see Figs 2-3, joint assembly 40, Paragraph 0041) comprising: - a bolt (Fig 2, bolt 50) extending (see Fig 2) in a longitudinal direction (see Fig 2) through a flange connection (Fig 2, flanges 42, 44, Paragraph 0041), the bolt (50) comprising a first portion (see Fig 2, Paragraph 0041, Examiner notes threaded portion 60 as a first portion) and a second portion (see Fig 2, Paragraph 0041 Examiner notes head 58 as a second portion), the first portion (see Fig 2) comprising a threaded section (Fig 2, threaded portion 60) at a first side (see Fig 2) of the flange connection (42, 44), the second portion (see Fig 2) comprising a head portion (Fig 2, head 58) at a second side (see Fig 2) of the flange connection (42, 44); - a nut (Fig 2, nut 54) screwed (see Fig 2, Paragraph 0041) on the threaded section (60); and - a spacer (Fig 3, collar 52) arranged (see Fig 2, Paragraph 0041) between the nut (54) and the flange connection (42, 44) or between (Paragraph 0041, Reed indicates each collar 52 is arranged between one of the flanges 42, 44 and the respective nut 54 or between one of the flanges 42, 44 and a head of the respective bolt 50) the head portion (58) and the flange connection (42, 44); wherein the spacer (52) is shaped (see Fig 3) with a non-cylindrical shape (see Fig 3, Paragraph 0042, Examiner notes the second member 64 is substantially U-shaped or V-shaped in cross-section taken in a plane through and containing the axis Y of the collar 52 as a non-cylindrical shape) to have a lower stiffness in the longitudinal direction (see Fig 2) under compression compared to a stiffness of a strictly cylindrical shape (see Fig 3, Paragraphs 0042-0044, Examiner notes collar 52 may be crushable or non-crushable, performs a dual roll of providing a linear stiffness and acting as a collar, and ensures that at an axial load lower than the capability of the bolt 50 and the crushing load of the collar 52 the bolt clamping load may be overcome to allow parting, separation of, the flanges 42 and 44 as to have a lower stiffness in the longitudinal direction under compression compared to a stiffness of a strictly cylindrical shape); wherein a combination (see Fig 3, Paragraphs 0042-0044) of the non-cylindrical shape (see Fig 3) and the larger elasticity (Paragraph 0044, Examiner notes the axial space 78 between the radially inner end 70 of the first portion 66 and the radially inner end 74 of the second portion 68 is reduced to zero as the larger elasticity) of the spacer (52) causes the spacer (52) to resist buckling by acting as a spring to compress under tension by the bolt (50) and then to expand upon a lengthening of the bolt (50) to preserve clamping integrity of the bolt assembly (40) (Paragraphs 0001-0005, Examiner notes the joint assembly is to remain structurally effective whilst limiting the load, deflection, passed from one side of the joint assembly to the other as to resist buckling by acting as a spring to compress under tension by the bolt and then to expand upon a lengthening of the bolt to preserve clamping integrity of the bolt assembly). Reed fails to teach wherein the bolt is comprised of a titanium alloy; wherein the spacer is comprised of a titanium alloy; wherein the spacer titanium alloy has a larger elasticity, defined by a lower elastic modulus, than the bolt titanium alloy; wherein the spacer is comprised of a Ti-3Al-8V-6Cr-4Mo-4Zr titanium alloy; wherein the bolt titanium alloy has a minimum yield strength above 500 MPa and a minimum guaranteed elongation at failure larger than 15 percent. However, Steeljrv teaches it is known to provide fasteners (see Pg 2, fastener categories; e.g. bolt, fastener assembly, etc.) of titanium alloy materials (see Pg 2). More specifically, Steeljrv teaches aerospace fasteners prefer titanium alloy materials (see Pg 2). Further, Steeljrv teaches, in Tables 1-2 on Pgs 2-4, various titanium alloys used for fasteners, e.g. bolt titanium alloy can be selected as ninth from top row: SP-700, Ti-4.5Al-3V-2Fe-2Mo, Near β type; and spacer titanium alloy can be selected as second to last row: TB9(βC), Ti-3Al-8V-6Cr-4Mo-4Zr, Metastable β). Therefore, as evidenced by Steeljrv, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the materials of the bolt and spacer of Reed to be of titanium alloys as taught by Steeljrv in Tables 1-2. Additionally, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the materials to be of titanium alloys, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious engineering design choice. It is also common knowledge to choose a material that has sufficient strength, durability, flexibility, hardness, and potential aesthetics, etc., for the application, intended use, and design considerations for that material. MPEP 2144.07. The rationale for supporting this conclusion of obviousness is to provide known materials of reduced weight, improved strength, increased corrosion resistance, etc. (Steeljrv, see Pgs 2-3) based on application, functional, and criticality requirements. Reed, in view of Steeljrv fails to teach wherein the spacer titanium alloy has a larger elasticity, defined by a lower elastic modulus, than the bolt titanium alloy; wherein the bolt titanium alloy has a minimum yield strength above 500 MPa and a minimum guaranteed elongation at failure larger than 15 percent. However, RMI teaches, for example, SP-700 has a modulus of elasticity of 110 GPa, yield strength of 972 MPa, and an elongation of 19% (see Pg 33). RMI further teaches, for example, Ti-3Al-8V-6Cr-4Mo-4Zr has a modulus of elasticity of 93-96 GPa (see Pg 35). Accordingly, RMI teaches wherein the spacer titanium alloy (see Pg 35) has a larger elasticity (see Pgs 33 and 35), defined by a lower elastic modulus (see Pg 35), than the bolt titanium alloy (see Pg 33); wherein the bolt titanium alloy (see Pg 33) has a minimum yield strength above 500 MPa (see Pg 33) and a minimum guaranteed elongation at failure larger than 15 percent (see Pg 33). Therefore, as evidenced by RMI, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine known properties of known materials, i.e. the spacer titanium alloy has a larger elasticity, defined by a lower elastic modulus, than the bolt titanium alloy; wherein the bolt titanium alloy has a minimum yield strength above 500 MPa and a minimum guaranteed elongation at failure larger than 15 percent, of RMI to modified Reed. The rationale for supporting this conclusion of obviousness is to provide titanium alloys for hot gas turbine components which provide attractive mechanical properties, corrosion and erosion resistance, heat transfer characteristics, etc. (RMI, Pgs 1-4). Regarding claim 2, modified Reed teaches the bolt assembly (40) of claim 1 and further teaches wherein the bolt titanium alloy (see Pg 33) has at least one of an elastic modulus between 107 GPa and 150 GPa (see Pg 33, RMI indicates a modulus of elasticity of 110 GPa), or a density smaller than 5 g/cc (see Pg 33, RMI indicates a density of 4.54 g/cm3). Regarding claim 8, modified Reed teaches the bolt assembly (40) of claim 1 and further teaches wherein the spacer (52) comprises a conic shaped lateral surface (see Fig 3, Examiner notes a conic shaped surface of first member 62 of collar 52 distal second member 64 as comprises a conic shaped lateral surface). Regarding claim 9, modified Reed teaches the bolt assembly (40) of claim 1 but fails to teach wherein the spacer comprises a conic through-hole. However, in a further embodiment of Reed in Fig 4, Reed teaches wherein the spacer (Fig 4, collar 52B) comprises a conic through-hole (see Fig 4, Paragraphs 0045-0047, Examiner notes the radially inner end 74 of the second portion 68 has a greater internal diameter than the radially inner end 70 of the first portion 66 as comprises a conic through-hole). Therefore, as evidenced by the further embodiment of Reed in Fig 4, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the spacer of modified Reed to comprise a conic through-hole as taught by the further embodiment of Reed in Fig 4. The rationale for supporting this conclusion of obviousness is to allow larger bolts in the flange as well as spread the flange contact load wider and over a greater area thus reducing the contact pressure in the flange directly (Reed, Paragraphs 0045-0047). Regarding claim 10, modified Reed teaches the bolt assembly (40) of claim 1 but fails to teach wherein the spacer comprises a lateral surface shaped as a conic hourglass, a curved hourglass or a mirrored curved hourglass. However, in a further embodiment of Reed in Fig 5, Reed teaches wherein the spacer (Fig 5, collar 52C) comprises a lateral surface shaped as a conic hourglass, a curved hourglass or a mirrored curved hourglass (see Fig 5, Paragraphs 0048-0050, Examiner notes the third member 80 is arranged at a second end 65 of the first member 62 so that the first member 62 is arranged axially between the second member 64 and the third member 80 as comprises a lateral surface shaped as a conic hourglass, a curved hourglass or a mirrored curved hourglass). Therefore, as evidenced by the further embodiment of Reed in Fig 5, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the spacer of modified Reed to comprise a lateral surface shaped as a conic hourglass, a curved hourglass or a mirrored curved hourglass as taught by the further embodiment of Reed in Fig 5. The rationale for supporting this conclusion of obviousness is to provide two areas of significantly different axial stiffness as well as fully isolating the collar function from the effects of lateral load casing bolt bending, and therefore, an eccentric load path, such that the threat of premature crushing of the collar is reduced (Reed, Paragraphs 0048-0050). Regarding claim 11, modified Reed teaches the bolt assembly (40) of claim 10 and further teaches wherein the spacer (52) comprises a cylindrical or conic through-hole (see Fig 5, Paragraphs 0048-0050, Examiner notes radially inner end 70 of the first portion 66, the radially inner end 74 of the second portion 68, the radially inner end 86 of the third portion 82, the radially inner end 90 of the fourth portion 84 and the first member 62 have the same internal diameter as comprises a cylindrical through-hole). Regarding claim 12, modified Reed teaches the bolt assembly (40) of claim 1 but fails to teach wherein the spacer comprises a reverse hourglass through-hole. However, in a further embodiment of Reed in Fig 6, Reed teaches wherein the spacer (Fig 6, collar 52D) comprises a reverse hourglass through-hole (see Fig 6, Paragraphs 0051-0053, Examiner notes the second member 64 of the collar 52D is arranged axially between the first member 62 and the third member 100 as comprises a reverse hourglass through-hole). Therefore, as evidenced by the further embodiment of Reed in Fig 6, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the spacer of modified Reed to comprise a reverse hourglass through-hole as taught by the further embodiment of Reed in Fig 6. The rationale for supporting this conclusion of obviousness is to provide the third member to crush at a second predetermined load or is arranged not to crush (Reed, Paragraphs 0051-0053). Regarding claim 13, modified Reed teaches the bolt assembly (40) of claim 1 but fails to teach wherein the spacer comprises a bulged out barrel form. However, in a further embodiment of Reed in Fig 6, Reed teaches wherein the spacer (Fig 6, collar 52D) comprises a bulged out barrel form (see Fig 6, Paragraphs 0051-0053, Examiner notes the second member 64 of the collar 52D is arranged axially between the first member 62 and the third member 100 as comprises a bulged out barrel form). Therefore, as evidenced by the further embodiment of Reed in Fig 6, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the spacer of modified Reed to comprise a bulged out barrel form as taught by the further embodiment of Reed in Fig 6. The rationale for supporting this conclusion of obviousness is to provide the third member to crush at a second predetermined load or is arranged not to crush (Reed, Paragraphs 0051-0053). Regarding claim 14, modified Reed teaches the bolt assembly (40) of claim 1 but fails to teach wherein the spacer comprises a lateral surface shaped as a double stepped cylinder having an outer diameter at ends thereof larger than an outer diameter in a central section between the ends. However, in a further embodiment of Reed in Fig 5, Reed teaches wherein the spacer (Fig 5, collar 52C) comprises a lateral surface shaped as a double stepped cylinder (see Fig 5, Paragraphs 0048-0050, Examiner notes the third member 80 is arranged at a second end 65 of the first member 62 so that the first member 62 is arranged axially between the second member 64 and the third member 80 as comprises a lateral surface shaped as a double stepped cylinder) having an outer diameter at ends (see Fig 5, Examiner notes outer diameters of second member 64 and third member 80 as having an outer diameter at ends) thereof larger (see Fig 5) than an outer diameter in a central section (see Fig 5, Examiner notes an outer diameter of a middle section of first member 62 as an outer diameter in a central section) between the ends (see Fig 5) (see Fig 5, Paragraphs 0048-0050, Examiner notes the radially outer end 72 of the first portion 66 and the radially outer end 76 of the second portion 68 of the second member 64 have a greater external diameter than the external diameter of the first member 62 and the radially outer end 88 of the third portion 82 and the radially outer end 92 of the fourth portion 84 of the third member 80 have a greater external diameter than the external diameter of the first member 62 as comprises a lateral surface shaped as a double stepped cylinder having an outer diameter at ends thereof larger than an outer diameter in a central section between the ends). Therefore, as evidenced by the further embodiment of Reed in Fig 5, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the spacer of modified Reed to comprise a lateral surface shaped as a double stepped cylinder having an outer diameter at ends thereof larger than an outer diameter in a central section between the ends as taught by the further embodiment of Reed in Fig 5. The rationale for supporting this conclusion of obviousness is to provide two areas of significantly different axial stiffness as well as fully isolating the collar function from the effects of lateral load casing bolt bending, and therefore, an eccentric load path, such that the threat of premature crushing of the collar is reduced (Reed, Paragraphs 0048-0050). Response to Arguments With respect to a Declaration from inventor Robert Heeter on Pg 5 of Applicant’s Remarks filed January 26, 2026, the Examiner acknowledges Applicant’s Declaration. Applicant's arguments filed January 26, 2026 have been fully considered but they are not persuasive. With respect to amended claim 1 on Pgs 5-6 of Applicant’s Remarks filed January 26, 2026, Applicant respectfully disagrees that “a minimum guaranteed elongation at failure larger than 15 percent” is not supported by the specification and presents Paragraphs 0010 and 0069. Applicant indicates “elongation at failure larger than 15 percent” in Paragraphs 0010 and 0069 makes clear that the elongation at failure is larger than 15%; such statements do not permit any interpretation that would allow an elongation at failure below 15% of any bolt, nor does it allow an interpretation that the elongation at failure of larger than 15% need merely be a typical elongation at failure of larger than 15% that would still allow for any bolt to have an elongation at failure of less than 15%. The Examiner agrees with Applicant that Paragraphs 0010 and 0069 makes clear that the elongation at failure is larger than 15% and thus, Applicant’s amended limitation of “a minimum guaranteed elongation at failure larger than 15 percent” appears to be supported by the specification. However, the Examiner respectfully notes that the amended limitation of “guaranteed” provides no additional weight as the elongation at failure occurs at larger than 15%. Further, with respect to Pgs 6-7 of Applicant’s Remarks filed January 26, 2026, Applicant further argues that SP-700 alloy would not meet this requirement because even with a typical elongation at failure of 19%, the minimum guaranteed elongation at failure is only 10%, which is below the required 15% and the person skilled in the art of gas turbine design would readily understand that the above-cited statements set an absolute floor for the elongation at failure that must be met to prevent dangerous or even catastrophic consequences in a gas turbine aircraft engine. The Examiner agrees that an absolute floor for the elongation at failure must be met to prevent dangerous or even catastrophic consequences in a gas turbine aircraft engine, however, the Examiner respectfully disagrees that SP-700 would not meet this requirement. One of ordinary skill in the art would understand that such “typical elongation at failure at 19%” would reasonably teach and/or suggest the claimed “minimum guaranteed elongation at failure larger than 15%”. As Applicant indicates on Pg 6, the “elongation at failure of larger than 15% need merely be a typical elongation at failure of larger than 15% that would still allow for any bolt to have an elongation at failure of less than 15%” and “Applicant buys and designs components with material specifications which state what the material has to be able to deliver X property value and reject lots that fail to meet that minimum X property value”; thus, such components, i.e. bolts, have not only an elongation of failure at less than 15% but also have an elongation at failure larger than 15%. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOCK WONG whose telephone number is (571)270-1349. The examiner can normally be reached Monday - Friday, 7:30am - 5:00pm (ET). 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, Kristina Fulton can be reached at (571)272-7376. 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. /J.W./Examiner, Art Unit 3675 /KRISTINA R FULTON/Supervisory Patent Examiner, Art Unit 3675
Read full office action

Prosecution Timeline

Apr 15, 2022
Application Filed
Jun 27, 2024
Non-Final Rejection — §103
Sep 16, 2024
Response Filed
Dec 12, 2024
Final Rejection — §103
Feb 10, 2025
Response after Non-Final Action
Feb 20, 2025
Request for Continued Examination
Feb 21, 2025
Response after Non-Final Action
Jun 17, 2025
Non-Final Rejection — §103
Sep 22, 2025
Response Filed
Oct 22, 2025
Final Rejection — §103
Jan 07, 2026
Response after Non-Final Action
Jan 26, 2026
Request for Continued Examination
Jan 28, 2026
Response after Non-Final Action
Feb 19, 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

5-6
Expected OA Rounds
34%
Grant Probability
78%
With Interview (+44.6%)
3y 3m
Median Time to Grant
High
PTA Risk
Based on 83 resolved cases by this examiner. Grant probability derived from career allow rate.

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