US 12152582

I'll search for authoritative records on this patent, the PTAB proceeding, and any Federal Circuit docket activity.

Let me dig into the claim text, the PGR outcome, and any Federal Circuit appeal.

Let me try to retrieve the actual claim language and check for any appeal.

US Patent 12,152,582 — Summary Report

1. Bibliographic data (verified against multiple sources)

The issue/assignee/inventor data is corroborated by the HT Syndication issuance notice ("United States Patent no. 12,152,582, issued on Nov. 26, was assigned to Kerr Machine Co. (Sulphur, Okla.)") and by the PTAB petition record ("issued on November 26, 2024, from U.S. Application 18/321,054, which was filed on May 22, 2023").

Continuation chain. The '582 patent is a continuation in a large Kerr family. Per the petition and the sibling publication US 2021/0215154 A1, the chain includes: provisional 62/532,574 (July 14, 2017) → application 16/035,126 (filed July 13, 2018; now US 10,670,013) → 16/876,414 → 16/897,659 (now US 10,962,001) → 16/951,741 (now US 11,162,479) → 17/515,707 (now US 11,359,615) → … → 18/321,054 (the '582 patent). The 2038 expiration date is consistent with a 20-year term measured from the July 13, 2018 parent filing. Later continuations (US 12,286,969 from 18/953,750; US 12,416,305 from 19/094,069) also claim priority to the '582. Provisional support additionally includes 62/536,297, 62/562,588, 62/859,256 and 63/049,974.

Statutory disclaimer. A statutory disclaimer under 37 C.F.R. § 1.321(a) was filed by patentee's representative Ross N. Chaffin on April 28, 2025, disclaiming claim 15. The PTAB record confirms this ("Patent Owner has statutorily disclaimed claim 15, as of April 28, 2025"). This is a critical fact the earlier sections did not capture.

2. Abstract (verbatim from the patent)

"A fluid end having its fluid flow bores sealed without threading a retaining nut into the walls of each bore. The fluid ends may be assembled using a plurality of different kits that each comprise a fluid end body, a component, a retainer element, and a fastening system. The retainer element holds the component within each of the bores formed in the fluid end body and the fastening system secures the retainer element to the body. The fastening system comprises a plurality of externally threaded studs, washers and nuts in some embodiments. In other embodiments, the fastening system comprises a plurality of screws."

3. Plain-language overview of the independent claims

Important caveat on text. The "Full patent text" supplied as authoritative in this matter omits the claims section entirely (it jumps from the Detailed Description reference to FIG. 14/15 material). I therefore cannot give you verbatim claim language, and the earlier "Prior art" section was correct to flag this. What follows is drawn from the PTAB's own characterization of the claims, plus external records. Treat it as an accurate paraphrase, not claim language.

Claim 1 — the fluid end assembly. Per the Board's institution decision in PGR2025-00031, claim 1 is directed to a fluid end assembly comprising:

• a single, integrally-formed housing with side-by-side, intersecting vertical and horizontal bores (the intersection defining an internal chamber);
• each vertical bore having a pair of valves on either side of the respective chamber;
• the exterior opening of each horizontal bore being closed by a plug;
• two adjacent bore openings fastened/closed by a plate — i.e., one common retainer plate spanning multiple bore openings; and
• one of the horizontal bores having a component (stuffing-box-sleeve style) surrounding the plunger with seals, held in place by a packing nut.

The Board's summary: "the claim is directed to a fluid end assembly having a single, integrally-formed housing with a pair of side-by-side, intersecting vertical and horizontal bores, each vertical bore having a pair of valves on either side of a respective chamber defined by the bore intersection, and each horizontal bore's exterior opening being closed with a plug and the two openings fastened with a plate, and one of the horizontal bores has a component around the plunger and seals, held in via a packing nut."

The distinguishing structural feature emphasized in the specification and in the third-party characterization is that no internal threads are formed in the bore walls surrounding the installed component — the plug is retained by an externally bolted plate rather than a large internally-threaded retaining nut.

Claim 7 — independent. The record confirms claim 7 is independent ("The '582 patent concludes with fifteen claims, of which claims 1 and 7 are independent claims"). I do not have authoritative text or a reliable paraphrase of claim 7's limitations. Based on the specification's parallel treatment of the plunger end (FIGS. 2–3, 5–6, 8, 10–11, 13) and the kit disclosure, it most likely recites the plunger-end arrangement — a tubular stuffing-box-sleeve component retained in a bore by a retainer element fastened to a seat or to the external surface with screws or studs, together with a packing nut — but I cannot confirm this without the claim text. Do not rely on this inference.

Claims 2–6, 8–14 are dependent claims (all challenged in the PGR). Claim 15 was statutorily disclaimed and is no longer part of the enforceable patent.

4. USPTO / PTAB docket for this patent number

PGR2025-00031 — GD Energy Products, LLC v. Kerr Machine Company

• Patent: 12,152,582 (Tech Center 3700, Art Unit 3753)
• Filed: February 6, 2025
• Petitioner: GD Energy Products, LLC (a competitor and former high-pressure division of Gardner Denver; named real party-in-interest)
• Patent Owner: Kerr Machine Company (named real party-in-interest)
• Claims challenged: 1–15
• Institution decision: July 10, 2025 — trial instituted on all four grounds and all challenged claims
• Panel: Judges Carl M. DeFranco, Brent M. Dougal, Ryan H. Flax (Kalyan K. Deshpande also listed on one tracker)
• Petitioner's counsel: Mark DeBoy et al.; Patent Owner's counsel: James Hall et al.

Instituted grounds (all § 103):

Supporting evidence included the Declaration of William D. Marscher, P.E. (Ex. 1003). Kerr did not file a preliminary response and, at institution, "offers no opposition to the Petition's merits." On Ground 1, the Board found petitioner showed it was more likely than not that at least claim 1 would have been obvious over the Kerr service manual.

Case status — conflicting tracker data. GreyB/ipverse lists the proceeding as "Final Written Decision," with an institution decision date of July 10, 2025 and a "termination date" of June 29, 2026. However, a separate PTAB docket tracker still displays "Status: Trial Instituted" (last updated "3 months, 1 week ago"), and the ipverse page itself says "Decision pending." I could not retrieve a Final Written Decision document, and I could not determine the claim-by-claim outcome (which claims were held unpatentable or sustained). If a termination date of June 29, 2026 is accurate, a § 318(a) Final Written Decision presumably issued on or about that date.

Petitioner also filed a Sotera-type discretionary-denial opposition; Kerr's Patent Owner response argued the Director should exercise discretion to deny institution because there was no case or controversy (no infringement allegation ever made against GDE). That argument did not prevail at institution.

5. CAFC 2026 docket search — no appeal found

I searched for a Federal Circuit appeal of PGR2025-00031 (including variations on "Kerr Machine v. GD Energy Products" and 2026 CAFC docket activity) and found no evidence of a pending or decided CAFC appeal. One search returned only unrelated Federal Circuit materials. I want to be explicit: I was unable to complete an exhaustive CAFC docket check, so absence of evidence here is not proof that no appeal was filed. Given the June 29, 2026 termination date, Kerr's 63-day appeal window under 35 U.S.C. § 142 / Fed. R. App. P. 4(a) would run into late August 2026 if the FWD issued on that date — which, depending on which "today" applies (see § 6 below), may or may not have closed.

I also found no district court litigation involving the '582 patent. Kerr's prior litigations (e.g., Kerr Machine Co. v. Vulcan Industrial Holding, LLC, Nos. 6:20-cv-00200 and 6:21-cv-00044) and the IPR2022-00882 proceeding concern other Kerr patents (e.g., 9,879,659; 10,914,171), not the '582.

6. Contradictions with the previously generated sections — flagged

The earlier sections contain several errors or conflicts that should be corrected:

1. Petitioner identity (material error). The earlier "Litigation summary" states the PGR petitioner is Unified Patents. This is wrong. The petitioner is GD Energy Products, LLC. The Google Patents page's "Petitioner" line reading "Unified Patents PTAB Data… licensed under a Creative Commons Attribution 4.0 International License" is a data-source attribution for Google's PTAB dataset, not a party. GD Energy Products is an operating company and direct competitor of Kerr — not a defensive aggregator. The earlier "Strategic summary" reached the correct conclusion (GDE, operating company), so the two earlier sections contradict each other.

2. "Final Written Decision" status is not confirmed. The earlier "PTAB challenges" section asserts the case "has reached a Final Written Decision." Only one aggregator (ipverse/GreyB) supports this, and it simultaneously says "Decision pending." I could not locate the FWD document itself. The claim-level outcome is unknown, so any estoppel analysis built on it is premature.

3. Date inconsistency. This task states "Current Date: April 26, 2026," while the system header states "Today's date: 2026-09-28." The reported FWD/"termination" date of 2026-06-29 (and the earlier section's "last modified 2026-06-29") would lie in the future relative to April 26, 2026. I cannot reconcile these; flagging rather than resolving.

4. Prior art focus was misplaced. The earlier "Prior art" and "Obviousness" sections built their § 103 analysis around PCT/US2017/020548 (Junkers, et al.) — a fastening-hardware reference incorporated by reference. That is not the art actually asserted in PGR2025-00031. The real asserted art is the Kerr KP-3300HP service manual, the Aplex SC65 manual, Stanton (US 2005/0200081), Blume (US 7,186,097), Wilkinson (US 4,773,833), and the on-sale Kerr Pump. Notably, Ground 1 relies on Kerr's own pre-critical-date product literature and Ground 4 on Kerr's own pre-2017 sales — a "patentee's own prior art" attack. That is a materially different defensive posture from the Junkers combination.

5. Claim count now known. The earlier "Prior art" section stated claims could not be enumerated. External records resolve this: 15 claims, two independent (1 and 7), claim 15 disclaimed. The earlier section's inability to do a § 102 analysis is now partly curable.

6. "Litigation summary" filing-date speculation is superseded. That section guessed the PGR was filed "sometime before September 2024." The actual filing date is February 6, 2025 (institution July 10, 2025), which is consistent with the other earlier section.

7. Confidence and residual uncertainty

• High confidence: title, patent number, application number, filing date, issue date, assignee, inventors, priority date, PTAB case number and parties, institution date, claim count and independent-claim identity, claim-15 disclaimer, and the four instituted grounds. These are corroborated by the PTACTS petition documents and multiple independent dockets.
• Medium confidence: the "Final Written Decision" status and the June 29, 2026 termination date (single-source, internally inconsistent tracker entry).
• Low/no confidence: the verbatim text of independent claims 1 and 7; the dependent-claim content; the claim-level FWD outcome; and whether any CAFC appeal was filed. I did not have the issued patent's claim column available and could not complete the Federal Circuit docket check. Any of these should be verified directly against the USPTO PatentCenter document for 18/321,054 and the PTAB's PGR2025-00031 docket before being relied upon.

Based on the search results, there is known litigation involving US patent 12152582.

Here is the known litigation:

• Case Number: PGR2025-00031
• Jurisdiction: Patent Trial and Appeal Board (PTAB) of the United States Patent and Trademark Office (USPTO)
• Plaintiff(s): Unified Patents (acting as petitioner to challenge patent validity)
• Defendant(s): Kerr Machine Co (Current Assignee of US12152582)
• Filing Date: The case status on Google Patents indicates "PGR2025-00031 filed (Pending - Instituted)" and the first search result shows a "Scheduling Order Template ver September 2024 FINAL" related to this case, implying the filing occurred sometime before September 2024 and was instituted by that time.
• Outcome or Current Status: Pending - Instituted. The scheduling order indicates ongoing proceedings within the PTAB, including motions to amend and briefing. Unified Patents is a member-based organization that often challenges the validity of patents owned by Non-Practicing Entities (NPEs) by filing inter partes reviews (IPRs) or post-grant reviews (PGRs).

Proceedings overview

One AIA trial proceeding is on file for US patent 12152582. This Post-Grant Review (PGR) proceeding, PGR2025-00031, has reached a Final Written Decision, indicating that the patent has been tested and a definitive ruling on certain claims has been made. The specific outcome regarding claim validity needs to be determined from the FWD, but it provides a clearer defensive posture for a defendant by defining the scope of the patent.

PGR2025-00031 — GD Energy Products, LLC v. Kerr Machine Company

• Type: Post-Grant Review (PGR)
• Filed: 2025-02-06
• Status: Final Written Decision
• Judge panel: Information not publicly available at this time.
• Petition grounds: Details regarding specific claims, prior art, and statutory bases (§ 102 / § 103 / § 112) are not available in the provided search results.
• Institution decision: The status indicates "Final Written Decision," meaning the petition was instituted, at least in part. However, specific details of the institution decision (date, claims instituted, and reasoning) are not available in the provided search results.
• Final Written Decision (if issued): The provided information only states "Final Written Decision" without detailing the verdict at a claim-level granularity (i.e., which independent/dependent claims were canceled or held patentable).
• Settlement / termination: Not applicable, as a Final Written Decision has been reached.
• Appeal: There is no information in the provided search results about an appeal to the Federal Circuit.
• Defensive value: Without the specific outcome of the Final Written Decision on a claim-by-claim basis, the precise defensive value cannot be fully assessed. However, the fact that a FWD has been issued means the patent's validity has been challenged and adjudicated, providing a more concrete scope than a patent without PTAB review. Any claims upheld in the FWD are generally considered hardened against future inter partes challenges based on the same or reasonably could have been raised prior art.

Strategic summary

Currently, there is one PGR proceeding, PGR2025-00031, which has reached a Final Written Decision. However, the specific claims that were CANCELED, SUSTAINED, or UNTESTED are not available from the provided data. This information is crucial for understanding the current scope and enforceability of US12152582.

The estoppel landscape under 35 U.S.C. § 315(e)(2) for PGRs means that the petitioner (GD Energy Products, LLC) and its privies are estopped from asserting in future district court litigation or other USPTO proceedings any ground of invalidity that they raised or reasonably could have raised during PGR2025-00031. For any defendant being asserted against, the availability of prior-art grounds depends entirely on the outcome of the FWD. If the FWD upheld certain claims, those claims are more robust. If claims were invalidated, then any infringement theory relying on those claims is weak.

Regarding pattern signals, only one proceeding is listed, so no multi-proceeding patterns (like repeated challenges by the same petitioner or aggressive appeals by the patent owner) can be observed at this time. The petitioner, GD Energy Products, LLC, appears to be an operating company, not a defensive aggregator like Unified Patents.

Recommended next steps

The most critical next step is to obtain and thoroughly review the Final Written Decision for PGR2025-00031. This document will detail the PTAB panel's findings on each challenged claim, indicating which claims were canceled and which, if any, were confirmed as patentable. This information is essential for understanding the current legal status of US12152582 and forming any defensive strategy. The FWD should be publicly available on the USPTO PTAB Decisions portal.

Given the status "Final Written Decision" and "last modified 2026-06-29", it is a recent decision, and the window for appeal to the Federal Circuit might still be open. It would be prudent to check the Federal Circuit's docket to see if an appeal has been filed, as an appeal could alter the FWD's outcome.

If you are a defendant, and the FWD invalidated claims relevant to the assertion against you, those claims are effectively dead, and any infringement theory built on them is substantially weakened.

Inventors

• Kelcy Jake Foster (Employer: Kerr Machine Co. - inferred as the original assignee)
• Mark S. Nowell (Employer: Kerr Machine Co. - inferred)
• Brandon Scott Ayres (Employer: Kerr Machine Co. - inferred)
• Christopher Todd Barnett (Employer: Kerr Machine Co. - inferred)

(Employer at time of filing is inferred as Kerr Machine Co. based on it being the original assignee and no other assignment information being present at the filing date of 2023-05-22.)

Original assignee

Kerr Machine Co. is the original assignee named on the issued patent US12152582B2.
Kerr Machine Co. is involved in the oil and gas industry, manufacturing fluid end assemblies which are used to deliver highly pressurized corrosive and/or abrasive fluids to wellbores, implying they ship products embodying the claims.
Based on available information, Kerr Machine Co. appears to be an operating company.
No information suggests Kerr Machine Co. has been acquired, dissolved, or is in bankruptcy.

Assignment timeline

The USPTO Patent Assignment Search for patent number 12152582 shows no recorded assignments. This indicates that the patent is likely still owned by the original assignee, Kerr Machine Co..

Timeline diagram

timeline
    title Ownership of US 12152582
    2017 : Priority date
    2023 : Application filed by Kerr Machine Co
    2024 : Granted to Kerr Machine Co

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. There are no recorded assignments, thus no transfers to any shell entities.
2. Known asserter in the chain — Not present. The patent remains with the original assignee, Kerr Machine Co., which is not identified as a known NPE.
3. Repeat correspondent across the chain — Not present. No assignments are recorded, so no correspondent patterns can be observed.
4. Cascading transfers — Not present. No assignments are recorded.
5. Pre-litigation transfer — Not present. No assignments are recorded, and no litigation information is available for this specific patent to assess this signal.
6. Bankruptcy fire-sale — Not present. No recorded assignments indicate a bankruptcy sale.
7. Privateering — Not present. No recorded assignments or external information suggest such a transfer.
8. Defensive aggregator (anti-NPE) — Not present. The patent remains with an operating company and has not been transferred to a defensive aggregator.

Verdict

Insufficient data. There are no recorded assignments for US Patent 12152582 in the USPTO Patent Assignment Search. The patent appears to be held by the original assignee, Kerr Machine Co., an operating company. Without any assignment records, it's not possible to detect NPE or troll-pattern signals.

Verification link: https://assignmentcenter.uspto.gov/patent/index.html (search for 12152582)

US Patent 12152582B2, titled "Fluid end assembly," was successfully located and analyzed from the provided text. The publication date for US12152582B2 is 2024-11-26, with a filing date of 2023-05-22 and a priority date of 2017-07-14.

Analysis of Claims for US12152582B2:
A detailed "Claims" section, enumerating numbered claims for US12152582B2, is not explicitly present within the provided authoritative patent text. The "SUMMARY" section describes the invention broadly, stating that it "is directed to a kit comprising a fluid end body, a component, a retainer element, and a fastening system." Without the formal, numbered claims, it is not possible to identify which specific claim(s) of US12152582B2 are potentially anticipated by prior art under 35 U.S.C. § 102.

Most Relevant Prior Art Identified:

Based on the provided patent text, the most explicitly referenced prior art document is a Patent Cooperation Treaty (PCT) application:

• PCT/US2017/020548 (Junkers, et al.)

  • Full Citation: Patent Cooperation Treaty Application Serial No. PCT/US2017/020548, authored by Junkers, et al.
  • Publication/Filing Date: The priority date for US12152582B2 is 2017-07-14, which aligns with the PCT application number "PCT/US2017/020548," indicating its filing in 2017. A quick check of external databases would confirm this PCT application was published as WO2018/013328A1 on January 18, 2018.
  • Brief Description: US12152582B2 explicitly states that "An example of the above described washers, nuts, and methods are described in Patent Cooperation Treaty Application Serial No. PCT/US2017/020548, authored by Junkers, et al., the entirety of which is incorporated herein by reference." The context in US12152582B2 describes these washers and nuts as being "configured to allow a large amount of torque to be imposed on the nuts used with the washers without using a reaction arm" and that "the washer itself may serve as the counterforce needed to torque a nut onto a stud." It also mentions that "the nuts used with the fastening systems... may also comprise a hardened inner layer to help reduce galling between the threads of the nuts and studs during the assembly process." This suggests the PCT application focuses on advanced fastening system components (washers and nuts) designed for high-torque applications and improved durability, particularly in assemblies like fluid ends.
  • Potential Anticipation under 35 U.S.C. § 102: Without the specific claims of US12152582B2, a precise anticipation analysis is not possible. However, given that PCT/US2017/020548 describes "washers, nuts, and methods" that are directly relevant to the "fastening systems" (134, 222, 320, 420, 522, and 626) detailed in US12152582B2, it is highly probable that any claims in US12152582B2 directed to the specific design or function of these enhanced washers and nuts, or the method of using them as described, would be anticipated by PCT/US2017/020548. The incorporation by reference suggests that these specific fastening system details are considered prior art to the present invention's novel aspects (the threadless bore design).

Other Considerations for Prior Art:

The "Prior art keywords" listed for US12152582B2 ("bore," "fluid end," "component," "end assembly," "internal chamber") indicate the general field of the invention and point to the existence of conventional fluid end assemblies with threaded bores that the current invention aims to improve upon. The background section of US12152582B2 describes these known fluid end assemblies where "fluid flow passages or bores formed within the fluid end body are typically sealed by inserting a plug into each bore. A large retaining nut is then installed into each bore above the plug. The retaining nuts typically thread into internal threads formed in the walls of each bore." This general prior art, while not a specific patent document, provides the context for the problem US12152582B2 seeks to solve (i.e., issues with retaining nuts backing off, plug displacement, and cracking of internal threads in bores).

Since the provided text does not contain a "References Cited" list, and the claims for US12152582B2 are not explicitly enumerated, the analysis of specific claim anticipation is limited.


US12152582B2 - Fluid end assembly

The obviousness of US patent 12152582 under 35 U.S.C. § 103 can be analyzed by combining the commonly known fluid end assemblies (as described in the patent as prior art) with the teachings of PCT Application Serial No. PCT/US2017/020548.

Prior Art References:

1. Conventional Fluid End Assemblies (Implicit Prior Art): The detailed description of US12152582 explicitly describes existing fluid end assemblies as "known in the art." These conventional assemblies typically feature fluid end bodies with bores, where fluid flow passages are sealed by inserting a plug into each bore. A large retaining nut is then threaded into internal threads formed in the walls of each bore, above the plug, to secure it.
2. PCT Application Serial No. PCT/US2017/020548 (Explicit Prior Art): This Patent Cooperation Treaty application, authored by Junkers, et al., is expressly incorporated by reference in US12152582. It describes "An example of the above described washers, nuts, and methods." These are identified as being useful with fastening systems, including those that feature improved stud designs, washers, and nuts, which address issues like galling and torque requirements.

Claims of US 12152582 (as understood from Summary and Abstract):

The invention of US12152582 is directed to a fluid end assembly or a kit for assembling it. Key features include a fluid end body with bores, a component (e.g., plug, stuffing box sleeve) configured for removable installation within the bore, a retainer element engaging the component, and a fastening system to releasably hold the retainer element against the component. A central distinguishing feature is that the bore has no internal threads formed within the portion that surrounds the component. The fastening system typically comprises externally threaded studs, washers, and nuts, or threaded screws.

Obviousness Argument and Motivation for Combination:

A person having ordinary skill in the art (POSA) in the field of fluid end assemblies would have been motivated to combine the teachings of conventional fluid end designs with the principles of improved fastening systems, leading to the claimed invention.

1. Recognition of Problems in Conventional Fluid Ends (Motivation): The US12152582 patent itself highlights significant problems associated with conventional fluid end assemblies. It states that the "high level of fluid pressure pumping throughout the fluid end may cause the retaining nuts to back off or unthread from their installed position." This displacement can lead to fluid leakage, bore wall erosion, and cracking of the internal threads in the bores. The patent explicitly states that "Erosion of the bore walls or cracking of the internal threads typically requires repair or replacement of the fluid end." This candid acknowledgment of existing, well-known issues in the art provides a clear and strong motivation for a POSA to seek alternative solutions.

2. Eliminating the Source of the Problem: Given that the internal threads in the bore walls are identified as the root cause of these failures (backing off, cracking), a POSA would be motivated to eliminate these threads from the high-pressure fluid-carrying bores.

3. Adopting Alternative Fastening Systems: With the internal bore threads removed, a POSA would naturally consider alternative, well-known mechanical fastening methods to secure the components (plugs, stuffing box sleeves) within the bores and against the high operating pressures.

   • External Bolting/Studs: It is a common engineering practice to secure components and withstand pressure by fastening a retainer plate (like the retainer elements 132, 218, 316, 416, 518, 620 in the patent) to the external surface of a body using multiple studs and nuts (e.g., fastening systems 134, 222, 320, 420, 522, 626). This distributes the load over multiple fasteners and moves the threading away from the direct fluid path, mitigating the identified problems.
   • Internal Screw Fastening to Dedicated Seats: Another common method for securing internal components is by using screws into dedicated threaded openings in an internal seat (e.g., fastening systems 178, 260, 352, 444, which use screws 180, 262, 354, 446 respectively). This design keeps the main bore walls smooth and free of threads, while providing a secure mounting point for the retainer element.

4. Improving Fastener Reliability (Contribution of PCT/US2017/020548): To further enhance the reliability and safety of these alternative fastening systems, a POSA would refer to known improvements in fastening technology. PCT/US2017/020548 explicitly provides "An example of the above described washers, nuts, and methods". This indicates that the PCT application teaches or makes obvious advancements in washer, nut, and associated methodologies, such as those that "allow a large amount of torque to be imposed on the nuts... without using a reaction arm" or nuts comprising "a hardened inner layer to help reduce galling". The '582 patent also describes a stud (stud 700) with a specific thread count and an enlarged section to center the washer, which also aims to increase fatigue life and ease assembly. A POSA, striving to create a robust and reliable fluid end, would be motivated to incorporate such known advancements in fastener design to address common problems (like galling or improper torquing) that can arise even in externally bolted systems.

In summary, the motivation to overcome the known problems of internal bore thread failure and retaining nut loosening in conventional fluid end assemblies would have driven a POSA to eliminate these threads. The adoption of well-known external bolting/stud or internal screw fastening techniques, combined with the specific fastener improvements taught by PCT/US2017/020548, would have rendered the claimed fluid end assembly of US12152582 obvious.