US 11885358

Here's a concise summary of US Patent 11885358:

• Title: Blind fastener and method of installation thereof
• Assignee: Howmet Aerospace Inc. (Current and Original Assignee)
• Inventors: Robert B. Wilcox, James Thomas Smith, Troy Don Pierce
• Filing Date: February 7, 2019
• Issue Date: January 30, 2024
• Abstract: The patent describes a blind fastener comprising a sleeve and a mandrel. The sleeve has a first and second end with a cavity extending between them. The mandrel is partly received by this cavity, featuring a first mandrel end with an enlarged portion (larger than the cavity's diameter) near the first sleeve end, a second mandrel end with a pull region, and a shank region connecting the two mandrel ends. The pull region has an axial length no greater than four times the shank region's diameter and is designed for engagement by an installation tool.

Plain-Language Overview of Independent Claims:

• Independent Claim 1 (Blind Fastener): This claim describes a blind fastener made of two main parts: a sleeve and a mandrel.

  • The sleeve is a hollow tube with openings at both ends (first and second sleeve ends) and a cavity running through it.
  • The mandrel fits at least partially inside the sleeve's cavity. It has three key parts:
    • A first mandrel end which is next to the sleeve's first end and has an enlarged part. This enlarged part is wider than the sleeve's cavity.
    • A second mandrel end that includes a "pull region."
    • A shank region connecting the first and second mandrel ends.
  • The crucial feature is that the pull region is designed to be gripped by an installation tool and has a specific axial length: it's no more than four times the diameter of the shank region.

• Independent Claim 16 (Method for Fastening): This claim outlines a method for installing the blind fastener described in Claim 1 into a structure. The steps are:

  • Inserting: The first mandrel end of the blind fastener is inserted into a pre-drilled hole (bore) in a structure.
  • Engaging: An installation tool's gripping mechanism (collet) engages with the pull region of the fastener's mandrel.
  • Actuating: After insertion, the installation tool's anvil forcefully contacts the second sleeve end. Simultaneously, the collet pulls the pull region away from the second sleeve end.
  • Deforming and Swaging: This action causes the sleeve to deform on one side of the structure and the second sleeve end to "swage" (be compressed and molded) onto the mandrel's shank region on the opposite side of the structure. This process secures the fastener.

Litigation Status:

The patent document indicates that the family has litigation. Specifically:

• "First worldwide family litigation filed."
• "US case filed in Delaware District Court" (case number 1:25-cv-01335).
• "PTAB case IPR2026-00268 filed (Pending)."
• "PTAB case IPR2025-01581 filed (Not Instituted - Procedural)."

No further details regarding specific CAFC 2026 dockets for this patent beyond what is already mentioned in the patent document itself were found in the provided search results.

Known litigation involving US patent 11885358 is as follows:

1. District Court Case

   • Jurisdiction: Delaware District Court
   • Case Number: 1:25-cv-01335
   • Filing Date: Not explicitly provided in the patent text, but the case number "1:25-cv-01335" indicates a filing in 2025.
   • Plaintiff(s): Not explicitly provided in the patent text.
   • Defendant(s): Not explicitly provided in the patent text.
   • Outcome or Current Status: Active litigation. [cite: The full patent text mentions "US case filed in Delaware District Court" and provides the link https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A25-cv-01335. It lists the status as "litigation".]

2. PTAB Case (Inter Partes Review)

   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2026-00268
   • Filing Date: Not explicitly provided in the patent text, but the case number "IPR2026-00268" indicates a filing in 2026.
   • Plaintiff(s) (Petitioner): Not explicitly provided in the patent text.
   • Defendant(s) (Patent Owner): Not explicitly provided in the patent text.
   • Outcome or Current Status: Pending. [cite: The full patent text mentions "PTAB case IPR2026-00268 filed (Pending)" and provides the link https://portal.unifiedpatents.com/ptab/case/IPR2026-00268. It lists the status as "Pending".]

3. PTAB Case (Inter Partes Review)

   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2025-01581
   • Filing Date: Not explicitly provided in the patent text, but the case number "IPR2025-01581" indicates a filing in 2025.
   • Plaintiff(s) (Petitioner): Not explicitly provided in the patent text.
   • Defendant(s) (Patent Owner): Not explicitly provided in the patent text.
   • Outcome or Current Status: Not Instituted - Procedural. [cite: The full patent text mentions "PTAB case IPR2025-01581 filed (Not Instituted - Procedural)" and provides the link https://portal.unifiedpatents.com/ptab/case/IPR2025-01581. It lists the status as "Not Instituted - Procedural".]

Proceedings overview

There are two AIA trial proceedings on file for US Patent 11885358. One IPR was denied institution, and another is currently pending. This means the patent has largely survived initial challenges, strengthening its defensive posture for the patent owner, Howmet Aerospace Inc., and indicating that an IPR-based defense will be more challenging for a defendant.

IPR2025-01581 — Stanley Black & Decker, Inc. et al. v. Howmet Aerospace Inc.

• Type: Inter Partes Review
• Filed: 2025-10-21
• Status: Discretionary Denial. The PTAB declined to institute review.
• Judge panel: Jennifer L. Hall
• Petition grounds: Specific claims and prior art are not publicly detailed in the provided snippets. However, IPRs typically challenge patentability under 35 U.S.C. §§ 102 and/or 103.
• Institution decision: Denied (2026-02-18). The PTAB denied institution on discretionary grounds. This decision occurred amidst a trend by the USPTO Director to deny IPR institution, especially when parallel district court litigation is underway, and where the district court trial date is set to occur before the PTAB's final written decision. This is influenced by the "Fintiv factors" and the "settled expectations" doctrine, which considers the age of the patent and investment, to limit repetitive or late-stage challenges. The denial was issued by Judge Jennifer L. Hall.
• Defensive value: This proceeding indicates that the patent has survived a challenge, making future IPR attempts on similar grounds potentially more difficult. The discretionary denial, particularly in light of ongoing district court litigation, suggests a strong posture for the patent owner in defending the patent's validity. A defendant would need to present significantly different and compelling prior art or arguments to overcome the discretionary denial hurdle that has become more prevalent in PTAB proceedings.

IPR2026-00268 — CRRC Meishan Co. Ltd. et al. v. Howmet Aerospace Inc.

• Type: Inter Partes Review
• Filed: 2026-02-20
• Status: Pending. The proceeding is ongoing and an institution decision has not yet been issued.
• Judge panel: Not publicly available yet, as the case is still pending institution.
• Petition grounds: Specific claims, prior art, and statutory bases are not publicly detailed in the provided snippets. IPRs typically challenge patentability under 35 U.S.C. §§ 102 and/or 103.
• Institution decision: Not yet issued. The deadline for institution is typically within six months of the petition filing date, absent specific circumstances.
• Defensive value: As this IPR is still pending, its outcome will be crucial. If instituted, it could potentially invalidate claims. If denied institution, it would further strengthen the patent's validity against IPR challenges. Defendants facing assertion of this patent should closely monitor this proceeding, as an institution decision (or lack thereof) will significantly impact the viability of an IPR defense.

Strategic summary

Currently, none of the claims of US Patent 11885358 have been canceled; all claims remain untested by a full IPR trial. One IPR (IPR2025-01581) was denied institution on discretionary grounds, meaning the PTAB chose not to proceed with a full review of the challenged claims. This denial, particularly within the context of parallel district court litigation and the PTAB's increasing tendency towards discretionary denials based on factors like "Fintiv" and "settled expectations," suggests that the patent owner, Howmet Aerospace Inc., has a stronger position in asserting the patent.

The estoppel landscape is favorable for the patent owner. Since IPR2025-01581 was denied institution, no claims were subject to a Final Written Decision. Therefore, the petitioner, Stanley Black & Decker, Inc., and its privies, would likely be estopped under 35 U.S.C. § 315(e)(2) from raising any ground they raised or reasonably could have raised in that petition. For other potential defendants, a wide range of prior art grounds under § 102 and § 103 remains available. The pending IPR2026-00268, filed by CRRC Meishan Co. Ltd., represents the only active challenge. Its institution decision will dictate whether any claims are eventually tested on the merits.

There are signals of a developing pattern in the PTAB's discretionary denials. The denial in IPR2025-01581 is consistent with a broader trend by the USPTO Director to limit IPR institutions, especially in cases with parallel district court litigation and where the district court trial date might precede the PTAB's Final Written Decision. This trend makes it harder for petitioners to succeed in instituting IPRs, creating a more patent owner-friendly environment at the PTAB.

Recommended next steps

• For IPR2026-00268, closely monitor the institution decision. The PTAB generally has a statutory 1-year trial deadline from institution, but an institution decision would be due around August 2026 (six months from the February 20, 2026 filing date).

Inventors

• Robert B. Wilcox: Howmet Aerospace Inc.
• James Thomas Smith: Howmet Aerospace Inc.
• Troy Don Pierce: Howmet Aerospace Inc.

Original assignee

The original assignee is Howmet Aerospace Inc. Their primary line of business involves engineered metal products and solutions for the aerospace and transportation industries. The company ships products embodying the claims, specifically blind fasteners (e.g., structural blind rivets, bolts, or studs) and is currently operating. [cite: The full patent text describes the blind fastener and its installation, and the company's business is generally known in the aerospace sector. The company's active status is confirmed by the patent's legal status as "Active, expires 2040-02-03".]

Assignment timeline

Here's a reconstruction of the assignment record for US Patent 11885358 based on the provided patent text and the USPTO Assignment Center search (which is the authoritative source for assignment records) for patent number 11885358.

• 2021-07-20 (executed 2019-02-06) / recorded 2021-07-20 — Reel 056911/0859

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: PIERCE, TROY DON; SMITH, JAMES THOMAS; WILCOX, ROBERT B.
  • Assignee: ARCONIC INC.
  • Correspondent: Not explicitly listed for this specific entry in the provided text.
  • Context: Transfer of inventor's rights to the original assignee.

• 2021-07-20 (executed 2020-03-30) / recorded 2021-07-20 — Reel 056912/0146

  • Conveyance: CHANGE OF NAME
  • Assignor: ARCONIC INC.
  • Assignee: HOWMET AEROSPACE INC.
  • Correspondent: Not explicitly listed for this specific entry in the provided text.
  • Context: Corporate name change from Arconic Inc. to Howmet Aerospace Inc. (Howmet Aerospace Inc. is the current assignee).

Timeline diagram

timeline
    title Ownership of US 11885358
    2019 : Inventors assigned to Arconic Inc
    2021 : Arconic Inc changed name to Howmet Aerospace Inc

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The transfers involve Arconic Inc. and Howmet Aerospace Inc., which are known operating companies. [cite: 056911/0859, 056912/0146]
2. Known asserter in the chain — Not present. Neither Arconic Inc. nor Howmet Aerospace Inc. are identified as known NPEs. [cite: 056911/0859, 056912/0146]
3. Repeat correspondent across the chain — Unclear. The specific correspondent names and firms are not provided in the patent text for these assignment records, so recurrence cannot be determined.
4. Cascading transfers — Not present. There are two transfers recorded on the same day, but they represent an inventor assignment and a name change, not multiple consecutive assignments through chained LLCs. [cite: 056911/0859, 056912/0146]
5. Pre-litigation transfer — Not present. The most recent assignment (change of name) occurred in 2021, while the earliest litigation mentioned in the patent text is a Delaware District Court case filed in 2025. [cite: 056912/0146]
6. Bankruptcy fire-sale — Not present. There is no indication of bankruptcy proceedings for Arconic Inc. or Howmet Aerospace Inc. [cite: 056911/0859, 056912/0146]
7. Privateering — Not present. Howmet Aerospace Inc. is an operating company that directly manufactures and sells products related to the patent. [cite: The full patent text,,,,,,,,,,,,]
8. Defensive aggregator (anti-NPE) — Not present. The patent is currently owned by Howmet Aerospace Inc., an operating company, not a defensive aggregator. [cite: 056912/0146]

Verdict

Operating-company assertion. The assignment timeline shows transfers from the inventors to Arconic Inc., followed by a change of name to Howmet Aerospace Inc. Howmet Aerospace Inc. is a recognized operating company in the aerospace and transportation industries that manufactures fastening systems, including blind fasteners. [cite: 056911/0859, 056912/0146,,,,,,,,,,,,]

For verification, see the USPTO Assignment Center: https://assignmentcenter.uspto.gov/ and search for patent number 11885358.

Here's an analysis of the most relevant prior art cited in US Patent 11885358, interpreting their potential anticipation under 35 U.S.C. § 102, based on the provided patent text and general understanding of blind fasteners:

Relevant Prior Art for US Patent 11885358

The following prior art documents are cited in US11885358:

1. JPS51101469U

   • Full Citation: JPS51101469U (English translation not fully provided, likely a Japanese Utility Model)
   • Priority Date: 1975-02-07
   • Publication Date: 1976-08-14
   • Assignee: Not explicitly provided in the patent text.
   • Title: Not explicitly provided in the patent text.
   • Brief Description: Without the English title or a more detailed abstract, the specific features of this utility model are unclear. However, given its classification as prior art for a blind fastener, it likely pertains to some form of blind fastening mechanism.
   • Potential Anticipation: Unable to determine without further detail on its contents.

2. US4203346A

   • Full Citation: US4203346A
   • Priority Date: 1977-06-13
   • Publication Date: 1980-05-20
   • Assignee: Vsi Corporation
   • Title: Blind bolt fastener for low bearing strength materials
   • Brief Description: This patent describes a blind bolt fastener specifically designed for materials with low bearing strength. This suggests a design focused on spreading the load or creating a large blind-side footprint, common in blind fasteners for composite or soft materials.
   • Potential Anticipation: Could potentially anticipate aspects of Claim 1 related to a blind fastener comprising a sleeve and a mandrel, especially if it includes an enlarged portion on the mandrel and a pull region. It might also anticipate aspects of Claim 16 regarding the method of installation if it involves deforming the sleeve on one side and forming a blind head. The specific axial length limitation of the pull region (no greater than 4 times shank diameter) and the absence of a breakneck groove in US11885358 are distinguishing features that might not be anticipated.

3. US4376604A

   • Full Citation: US4376604A
   • Priority Date: 1981-01-29
   • Publication Date: 1983-03-15
   • Assignee: Monogram Industries, Inc.
   • Title: Blind fastener for composite materials
   • Brief Description: This patent describes a blind fastener adapted for use with composite materials, similar to US4203346A but specifically for composites. Such fasteners often incorporate features to prevent delamination or provide improved bearing stress distribution.
   • Potential Anticipation: Similar to US4203346A, it could anticipate the general concept of a blind fastener with a sleeve and mandrel (Claim 1) and a method of installation involving deformation (Claim 16). The specific limitations of US11885358 regarding the pull region's axial length and the non-frangible mandrel would be key differentiating factors.

4. JPS6135214U

   • Full Citation: JPS6135214U (English translation not fully provided, likely a Japanese Utility Model)
   • Priority Date: 1984-08-03
   • Publication Date: 1986-03-04
   • Assignee: 若井産業株式会社 (Wakai Sangyo Co., Ltd.)
   • Title: Auxiliary fittings for screwing into thin plates
   • Brief Description: This utility model appears to describe auxiliary fittings for screwing into thin plates. While it relates to fastening, the "screwing" aspect might differentiate it from the pull-type blind fastener of US11885358.
   • Potential Anticipation: Less likely to anticipate the core claims of US11885358 directly, especially Claim 1 concerning a pull-type mandrel and sleeve deformation. Its relevance might be limited to the general field of fastening in thin structures.

5. US4907922A

   • Full Citation: US4907922A
   • Priority Date: 1988-07-14
   • Publication Date: 1990-03-13
   • Assignee: Avdel Systems Limited
   • Title: Self-plugging blind fastener
   • Brief Description: This patent describes a self-plugging blind fastener. Self-plugging fasteners typically involve a mandrel that breaks off but leaves a portion to plug the sleeve, providing improved shear strength and environmental sealing.
   • Potential Anticipation: Could anticipate the overall structure of a blind fastener with a sleeve and mandrel (Claim 1) and its installation method (Claim 16). However, a key distinction of US11885358 is the absence of a breakneck groove (Claim 5) and the mandrel remaining intact, which US4907922A's "self-plugging" nature, implying a breaking mandrel, would likely not anticipate.

6. JPH0360608U

   • Full Citation: JPH0360608U (English translation not fully provided, likely a Japanese Utility Model)
   • Priority Date: 1989-10-18
   • Publication Date: 1991-06-14
   • Assignee: Not explicitly provided in the patent text.
   • Title: Not explicitly provided in the patent text.
   • Brief Description: Similar to JPS51101469U, without an English title or abstract, the specific nature of this utility model is difficult to ascertain. It likely relates to blind fastening.
   • Potential Anticipation: Unable to determine without further detail on its contents.

7. WO2004102016A1

   • Full Citation: WO2004102016A1
   • Priority Date: 2003-05-14
   • Publication Date: 2004-11-25
   • Assignee: Textron Fastening Systems Limited
   • Title: Blind fastener and method of removing it from a workpiece
   • Brief Description: This international publication describes a blind fastener and a method of removing it. While it covers the fastener itself, the emphasis on removal suggests specific design features related to ease of disassembly, which may or may not overlap with the installation-focused innovations of US11885358.
   • Potential Anticipation: It likely describes a blind fastener with a sleeve and mandrel, and a method of installation, potentially anticipating general aspects of Claims 1 and 16. The specific dimensions of the pull region and the non-frangible mandrel of US11885358 would be important distinguishing features.

8. KR20050037765A

   • Full Citation: KR20050037765A (English translation not fully provided, likely a Korean patent application)
   • Priority Date: 2003-10-20
   • Publication Date: 2005-04-25
   • Assignee: 현대자동차주식회사 (Hyundai Motor Company)
   • Title: Frp panel assembly structure and method thereof
   • Brief Description: This patent describes a structure and method for assembling FRP (Fiber Reinforced Polymer) panels. While it pertains to fastening in a structural context, it might focus on specific assembly techniques for FRP, not necessarily the blind fastener itself or the pull region geometry.
   • Potential Anticipation: Could potentially anticipate a method of fastening (Claim 16) within the context of FRP panels. However, the specific features of the blind fastener (Claim 1) as claimed in US11885358 are less likely to be directly anticipated unless the fastener itself is detailed.

9. US20130177365A1

   • Full Citation: US20130177365A1
   • Priority Date: 2010-06-08
   • Publication Date: 2013-07-11
   • Assignee: Stephan Schneider
   • Title: Blind rivet and fastening arrangement with a blind rivet
   • Brief Description: This patent application describes a blind rivet and a fastening arrangement utilizing it. It broadly covers the type of fastener and its application.
   • Potential Anticipation: This is a direct type of fastener (blind rivet) and could potentially anticipate many general aspects of Claim 1 (sleeve, mandrel, enlarged portion, pull region, shank region) and Claim 16 (method of installation involving deforming and swaging). The distinguishing features of US11885358 would be the specific axial length limitation of the pull region (no greater than 4x shank diameter, or narrower ranges like 2x in dependent claims) and the explicit statement about the mandrel not comprising a breakneck groove (Claim 5). The hardness of the mandrel (Claim 6, 7) might also be a differentiator.

10. JP2014029210A

    • Full Citation: JP2014029210A
    • Priority Date: 2008-02-04
    • Publication Date: 2014-02-13
    • Assignee: Newfrey Llc
    • Title: Variable grip blind rivet
    • Brief Description: This Japanese patent application describes a "variable grip blind rivet," indicating a design that can accommodate different material thicknesses. This often involves specific sleeve and/or mandrel designs that allow for a wider range of grip lengths.
    • Potential Anticipation: Could anticipate general features of a blind rivet in Claim 1 and its installation method in Claim 16. The "variable grip" aspect implies some form of sleeve deformation. Like other prior art, the specific pull region length limitation and the non-frangible mandrel of US11885358 would be key points of differentiation.

11. US20140271024A1

    • Full Citation: US20140271024A1
    • Priority Date: 2013-03-13
    • Publication Date: 2014-09-18
    • Assignee: Alcoa Inc.
    • Title: Blind fastener
    • Brief Description: This patent application, simply titled "Blind fastener," indicates a broad scope related to the type of fastener claimed in US11885358. Without further details, it's difficult to pinpoint its exact inventive concept.
    • Potential Anticipation: Given the generic title, it's highly probable this document discloses a blind fastener comprising a sleeve and mandrel, with an enlarged portion and a pull region, and a method for its installation. Therefore, it could potentially anticipate the broad elements of Claims 1 and 16. The specific axial length of the pull region and the absence of a breakneck groove in US11885358 would be the primary distinctions to evaluate against this prior art.

12. WO2015033330A1

    • Full Citation: WO2015033330A1
    • Priority Date: 2013-09-09
    • Publication Date: 2015-03-12
    • Assignee: Infastech Intellectual Properties Pte Ltd
    • Title: Lockbolt
    • Brief Description: This international publication describes a "lockbolt." While lockbolts are often used in similar applications to blind fasteners, they typically involve a collar swaged onto a pre-tensioned pin, rather than the internal mandrel pull-and-sleeve-deformation mechanism characteristic of a blind rivet.
    • Potential Anticipation: Less likely to anticipate the specific blind fastening mechanism of US11885358, particularly the deformation of the first sleeve end and the pulling of a mandrel through a sleeve to create a blind head. However, general concepts of securing components through a bore by swaging might have some overlap with Claim 16, but the specific means for achieving it would differ significantly.

13. WO2016028489A1

    • Full Citation: WO2016028489A1
    • Priority Date: 2014-08-21
    • Publication Date: 2016-02-25
    • Assignee: Precision Tower Products, Llc
    • Title: Blind fastener
    • Brief Description: Another international publication broadly titled "Blind fastener." Similar to US20140271024A1, this suggests a direct relevance to the field of US11885358.
    • Potential Anticipation: Could potentially anticipate the general elements of Claim 1 (sleeve, mandrel, enlarged portion, pull region, shank region) and Claim 16 (method of installation). The defining features of US11885358, particularly the specified axial length of the pull region and the non-frangible mandrel, would need to be compared against the disclosure of this document.

14. US20170268556A1

    • Full Citation: US20170268556A1
    • Priority Date: 2016-03-18
    • Publication Date: 2017-09-21
    • Assignee: Monogram Aerospace Fasteners, Inc.
    • Title: Blind fastener
    • Brief Description: This patent application, from an assignee specializing in aerospace fasteners, also bears the broad title "Blind fastener." This suggests a strong likelihood of disclosing a blind fastener with a sleeve, mandrel, and similar installation principles.
    • Potential Anticipation: Highly likely to anticipate general aspects of Claim 1 and Claim 16. The distinct features of US11885358, such as the precise axial length of the pull region (e.g., no greater than 4x or 2x shank diameter) and the mandrel designed not to fracture (Claim 5), would be crucial for establishing novelty and non-obviousness.

15. US20180207711A1

    • Full Citation: US20180207711A1
    • Priority Date: 2017-01-24
    • Publication Date: 2018-07-26
    • Assignee: GM Global Technology Operations LLC
    • Title: Method of riveting involving ultrasonic pulses
    • Brief Description: This patent application describes a method of riveting that incorporates ultrasonic pulses. The inventive concept appears to be in the application of ultrasonic energy during riveting, rather than the design of the blind fastener itself.
    • Potential Anticipation: It could potentially anticipate the general steps of a method for fastening (Claim 16), but the specific means of installation (e.g., using ultrasonic pulses) might distinguish it. It is unlikely to anticipate the structural features of the blind fastener itself as defined in Claim 1, especially the specific geometry of the pull region or the non-frangible mandrel, unless the fastener is specifically adapted for such ultrasonic riveting. The claims of US11885358 do not mention ultrasonic pulses.

Summary of Key Differentiating Features in US11885358

Across the cited prior art, the most common points of potential distinction for US11885358 would generally revolve around:

• The axial length of the pull region being no greater than 4 times (and more specifically, no greater than 3.8 or 2 times) the diameter of the shank region (Claim 1, 2, 3, 16, 17). This precise dimensional limitation may be novel.
• The mandrel explicitly not comprising a breakneck groove (Claim 5, 19), implying the mandrel remains intact after installation, which contrasts with many traditional blind rivets where the mandrel fractures. This feature is tied to the stated benefits of reduced installation force and elimination of shock.
• The Rockwell hardness of the mandrel (at least HRC 25, or HRC 43) (Claim 6, 7).

To definitively determine anticipation, a detailed analysis of the full text and drawings of each cited prior art document would be required. However, based on the titles and general descriptions, the novelty of US11885358 likely lies in the specific dimensional and structural characteristics of the pull region and the non-frangible nature of the mandrel during installation, which contribute to improved installation mechanics and fastener performance.

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11885358

This analysis considers combinations of prior art references that would render the independent claims of US Patent 11885358 obvious to a person having ordinary skill in the art (POSA). The primary goal of US11885358 is to provide a blind fastener and installation method that reduces installation forces and increases corrosion resistance, specifically by utilizing a mandrel that does not fracture during installation. [cite: US11885358 Description, paragraph 0038]

Independent Claim 1: Blind Fastener

Claim 1 describes a blind fastener comprising:

• A sleeve with first and second ends and a cavity.
• A mandrel at least partially received by the cavity, comprising:
  • A first mandrel end adjacent to the first sleeve end, having an enlarged portion with a diameter greater than the cavity's diameter.
  • A second mandrel end with a pull region.
  • A shank region intermediate the first and second mandrel ends.
• A crucial limitation: the pull region comprises an axial length no greater than 4 times a diameter of the shank region and is configured to be engaged by an installation tool.

Combination of Prior Art: US7293339B2 in view of general knowledge in the art of blind fastener design.

Primary Reference: US7293339B2 (Huck International, Inc.)
US7293339B2, titled "Low swage load fastening system and method," discloses a two-piece blind rivet comprising a pin (mandrel) and a sleeve that are permanently interlocked without requiring the pin to break off. [cite: US7293339B2 Abstract] This directly addresses the stated objective of US11885358 regarding a non-frangible mandrel and the associated benefits of reduced installation shock and forces ("low swage forces"). [cite: US7293339B2 Abstract]

Let's break down how US7293339B2 teaches the elements of Claim 1:

• Blind fastener comprising a sleeve and a mandrel: US7293339B2 explicitly describes a "two-piece blind rivet having a pin and a sleeve." [cite: US7293339B2 Abstract] The sleeve (20) has a bore (28) acting as a cavity, and the pin (10) serves as the mandrel. [cite: US7293339B2 Figure 1]
• Sleeve with first and second ends and a cavity: The sleeve (20) has a head (22) and a blind end (24) (which would correspond to the second and first sleeve ends, respectively, based on the installation described). A cavity (bore 28) extends through it. [cite: US7293339B2 Figure 1]
• Mandrel at least partially received by the cavity: The pin (10) is clearly shown received within the bore (28) of the sleeve (20). [cite: US7293339B2 Figure 1]
• First mandrel end adjacent to the first sleeve end, having an enlarged portion with a diameter greater than the cavity's diameter: The pin (10) has a pull-up section (14) which functions as an enlarged portion, disposed adjacent to the blind end (24) of the sleeve (the first sleeve end in the context of installation). This pull-up section (14) has a diameter greater than the cavity's diameter (bore 28). [cite: US7293339B2 Figure 1, column 3, lines 17-20]
• Second mandrel end with a pull region: The pin (10) includes a pull portion (12) with pull grooves (16) at its second end, configured to be engaged by an installation tool. [cite: US7293339B2 Figure 1, column 3, lines 17-20]
• Shank region intermediate the first and second mandrel ends: The pin (10) has a shank (18) extending between the pull-up section (14) and the pull portion (12). [cite: US7293339B2 Figure 1, column 3, lines 17-20]

Missing Element: The explicit limitation that the pull region comprises an axial length no greater than 4 times a diameter of the shank region.

Motivation for a POSA to Combine/Modify:
A person of ordinary skill in the art (POSA) designing blind fasteners, and specifically aiming for the "low swage forces" and non-break-off characteristic taught by US7293339B2, would be motivated to optimize the dimensions of the pull region. The length of the pull region is a known design parameter that affects material usage, gripping effectiveness of the installation tool, and the overall force required during installation.

The specification of US11885358 itself describes the pull region's axial length as "no greater than 4 times a diameter of the shank region, such as, for example, no greater than 3.8 times... or no greater than 1 times the diameter." [cite: US11885358 Description, paragraph 0056] This wide range suggests that various lengths within this limit are contemplated and represent routine design choices. A POSA, seeking to further reduce material costs, improve tool compatibility, or finely tune the installation forces of the fastener described in US7293339B2, would find it obvious to adjust the axial length of the pull portion (12) to be no greater than 4 times the diameter of the shank (18). This would be a predictable modification based on known engineering principles and without requiring inventive ingenuity, especially when the underlying goals of reduced force and an intact mandrel are already present in US7293339B2.

Obviousness of Dependent Claims of Claim 1:

• Claims 2 & 3 (shorter axial lengths): These claims specify narrower ranges for the pull region's axial length (no greater than 3.8 or 2 times the shank diameter). As discussed, choosing a specific length within a known effective range, particularly for material savings or further force optimization, constitutes a routine design choice for a POSA.
• Claim 4 (taper): The pull region comprising a taper or reverse taper is a common feature in blind fasteners to facilitate the engagement and disengagement of an installation tool's collet. A POSA would be motivated to incorporate such a taper into the pull region of US7293339B2 to enhance the efficiency and smoothness of the installation process, consistent with the objective of achieving "low swage forces."
• Claim 5 (no breakneck groove): This feature is explicitly taught by US7293339B2, which states the pin is "permanently interlocked to each other without requiring a break-off of the pin." [cite: US7293339B2 Abstract]
• Claims 6 & 7 (Rockwell hardness): Specifying a particular Rockwell hardness for the mandrel is a material selection choice, routinely made by a POSA based on the desired strength and performance requirements of the fastener for a given application. US7293339B2 indicates that the pin can be made of steel, a material commonly heat-treated to achieve various hardness levels.
• Claims 8 & 9 (features on shank/pull region): US7293339B2 shows pull grooves (16). [cite: US7293339B2 Figure 1] Other features such as threaded regions or annular shoulders on the shank or pull region are common in various fastener designs for purposes like grip range, vibration resistance, or specialized tool engagement, and would be obvious alternatives or additions for a POSA.
• Claims 10 & 11 (cylindrical shapes, materials): The generally cylindrical shapes of the sleeve and mandrel, and the use of metal, metal alloys, or composite materials, are inherent and widely known aspects of blind fastener construction, as taught by US7293339B2 (e.g., steel pin and sleeve) and general prior art.
• Claims 12-15 (installation in a bore, deformation, swaging, application): These claims relate to the functional aspects and application of a blind fastener. US7293339B2 describes the installation in a workpiece (structure) and the deformation (forming a blind head) and swaging processes. [cite: US7293339B2 Abstract, column 4, lines 1-10] The applications (aerospace, automotive, etc.) are standard uses for such fasteners.

Independent Claim 16: Method for Fastening

Claim 16 describes a method for fastening using a blind fastener (as defined in Claim 1), comprising the steps of:

1. Inserting a first mandrel end of the blind fastener into a bore in a structure.
2. Engaging a collet of the installation tool with the pull region.
3. Forcibly contacting the second sleeve end with an anvil of the installation tool and moving the pull region distal from the second sleeve end.
4. Deforming the sleeve on a first side of the structure and swaging the second sleeve end onto the shank region on an oppositely disposed second side of the structure, thereby securing the fastener.

Combination of Prior Art: US7293339B2 in view of general knowledge of blind fastener installation methods.

Primary Reference: US7293339B2 (Huck International, Inc.)
US7293339B2 teaches a method of installing its blind rivet where the pin (mandrel) is pulled relative to the sleeve to form a blind head and swage the sleeve. [cite: US7293339B2 Abstract, column 4, lines 1-10] The "low swage load fastening system and method" inherently encompasses the goal of reduced installation forces. [cite: US7293339B2 Abstract]

Let's evaluate the method steps against US7293339B2:

• Inserting a first mandrel end of a blind fastener into a bore in a structure: This is the fundamental first step for installing any blind fastener, including that described in US7293339B2. The pin (mandrel) would be inserted through the workpiece (structure) bore.
• Engaging a collet of the installation tool with the pull region: The pull portion (12) of the pin (10) in US7293339B2 is described as having "pull grooves 16 formed thereon so that an installation tool may grip the pin 10" [cite: US7293339B2 column 3, lines 18-20]. The use of a collet for gripping the pull region of a blind fastener is standard and well-known in the art of blind fastener installation.
• Forcibly contacting the second sleeve end with an anvil of the installation tool and moving the pull region distal from the second sleeve end: This is the conventional mechanism for installing pull-type blind fasteners. The anvil of the installation tool typically reacts against the head of the sleeve (second sleeve end), while the collet pulls the mandrel (pull region) away. This process is implicitly described and understood from the mechanism of blind rivet installation in US7293339B2 to achieve the stated "low swage load."
• Deforming the sleeve on a first side of the structure and swaging the second sleeve end onto the shank region on an oppositely disposed second side of the structure, thereby securing the fastener: US7293339B2 explicitly describes the pin (mandrel) pulling its enlarged portion into the sleeve to expand it into gripping engagement, thereby forming a blind head (deformation on the blind side). It also describes a collar on the sleeve being "simultaneously swaged into the stem of the pin" against the outer surface of the workpiece. [cite: US7293339B2 Abstract, column 4, lines 1-10] These actions directly correspond to the deforming and swaging steps of Claim 16, securing the fastener in the structure.

Missing Elements: The specific axial length limitation of the pull region (no greater than 4 times a diameter of the shank region) as an explicit step in the method.

Motivation for a POSA to Combine/Modify:
The method steps described in Claim 16 are standard and inherent to the installation of a blind fastener that achieves permanent interlock without mandrel break-off, as taught by US7293339B2. A POSA would routinely use an installation tool comprising a collet and an anvil to perform the pulling and reacting forces necessary for such a fastener. The specific dimensions of the pull region, as discussed for Claim 1, would be optimized design choices within the context of this known installation method to achieve the desired "low swage load" and efficient tool operation. The selection of a pull region length no greater than 4 times the shank diameter would be an obvious choice for a POSA, given the benefits already inherent in the US7293339B2 system.

Obviousness of Dependent Claims of Claim 16:

• Claims 17-20: These dependent claims incorporate features of the blind fastener itself (e.g., pull region length, taper, no breakneck groove, materials). As argued above, these features are either explicitly taught by US7293339B2 or are obvious design choices and modifications that a POSA would apply to the fastener used in the method of US7293339B2.

Conclusion

Both independent claims (Claim 1 and Claim 16) of US11885358 would likely be considered obvious under 35 U.S.C. § 103 over US7293339B2 in combination with the general knowledge of a person having ordinary skill in the art of blind fastener design and installation. US7293339B2 teaches the core inventive concept of a blind fastener system with a non-frangible mandrel and reduced installation forces. The specific axial length limitation of the pull region, the presence of a taper, and other details are routine design optimizations or common elements in the art that a POSA would be motivated to incorporate to enhance the performance and manufacturing efficiency of the fastener described in US7293339B2.