DCT
1:25-cv-01335
Howmet Aerospace Inc v. Stanley Engineered Fastening LLC
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Howmet Aerospace Inc. (Delaware)
- Defendant: Stanley Engineered Fastening, LLC (Delaware); Avdel UK Ltd. (United Kingdom); Avdel Holding Limited (United Kingdom)
- Plaintiff’s Counsel: Greenberg Traurig, LLP
- Case Identification: 1:25-cv-01335, D. Del., 10/31/2025
- Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant Stanley Engineered Fastening is a Delaware limited liability company and therefore resides in the district, and because the foreign Avdel defendants are subject to personal jurisdiction in the district.
- Core Dispute: Plaintiff alleges that Defendants’ Avdel Avbolt ECO line of blind fasteners, and the method of installing them, infringes a patent related to blind fastener technology featuring a non-fracturing mandrel.
- Technical Context: Blind fasteners are mechanical components used to join materials where access is limited to only one side, a common requirement in aerospace, automotive, and structural assembly.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendants with pre-suit notice of infringement via a letter dated May 15, 2025, which Defendants acknowledged, leading to subsequent discussions between the parties prior to the lawsuit's filing.
Case Timeline
| Date | Event |
|---|---|
| 2019-02-07 | ’358 Patent Priority Date |
| 2024-01-30 | ’358 Patent Issue Date |
| 2025-02-05 | Defendant allegedly publishes brochure for installation tool |
| 2025-02 | Defendant allegedly imports an "Avbolt Eco Assembly Machine" |
| 2025-05-02 | Plaintiff allegedly begins marking its product packaging with patent number |
| 2025-05-06 | Defendant allegedly posts promotional YouTube video for Accused Product |
| 2025-05-07 | Defendant allegedly offers Accused Product for sale in a datasheet |
| 2025-05-15 | Plaintiff sends notice letter of infringement to Defendant |
| 2025-05-23 | Defendant acknowledges receipt of Plaintiff's notice letter |
| 2025-05-29 | Parties engage in discussions regarding infringement allegations |
| 2025-09 | Defendant allegedly offers Accused Product for sale at a trade show |
| 2025-10-31 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 11,885,358 - Blind fastener and method of installation thereof
- Patent Identification: U.S. Patent No. 11,885,358, “Blind fastener and method of installation thereof,” issued January 30, 2024. (Compl. ¶20).
The Invention Explained
- Problem Addressed: The patent background describes the challenges in designing fasteners for "blind installation" scenarios where only one side of a workpiece is accessible, noting that conventional fasteners can fail due to fatigue stresses or geometric variations in the installation bore. (Compl. ¶¶ 21-22; ’358 Patent, col. 1:12-20).
- The Patented Solution: The invention is a two-piece blind fastener composed of an outer sleeve and an inner mandrel. An installation tool grips a "pull region" on the mandrel and pulls it through the sleeve. This action deforms the "blind" end of the sleeve to form a head and "swages" the near end of the sleeve into grooves on the mandrel's shank, creating a secure, vibration-resistant joint. (’358 Patent, Abstract; col. 6:46-53). A key aspect is that the mandrel is designed to withstand the installation forces without breaking, unlike some conventional blind fasteners. (Compl. ¶24; ’358 Patent, col. 5:8-16). Figure 1 of the patent illustrates the distinct components of the fastener, including the sleeve (102), mandrel (112), pull region (120), and shank region (122). (’358 Patent, Fig. 1).
- Technical Importance: This non-fracturing design can improve corrosion resistance by not creating an exposed break-surface and may reduce the peak force required for installation, potentially allowing for lighter, more ergonomic tools and reducing shock loads on the structure being assembled. (Compl. ¶24; ’358 Patent, col. 4:46-58).
Key Claims at a Glance
- The complaint asserts independent apparatus claim 1 and independent method claim 16. (Compl. ¶¶ 47-48).
- Independent Claim 1 (Apparatus) requires:
- A sleeve with a first end, a second end, and a cavity.
- A mandrel partially received by the sleeve's cavity.
- The mandrel comprising a first end with an enlarged portion, a second end with a pull region, and an intermediate shank region.
- A specific dimensional constraint: "the pull region comprises an axial length no greater than 4 times a diameter of the shank region."
- Independent Claim 16 (Method) requires the steps of:
- Inserting a blind fastener (having the same structural and dimensional limitations as the fastener in claim 1) into a bore.
- Engaging a collet of an installation tool with the pull region.
- Moving the pull region away from the sleeve's second end.
- Deforming the sleeve on one side of the structure and swaging the sleeve onto the shank region on the opposite side.
III. The Accused Instrumentality
Product Identification
- The complaint identifies the "Avdel Avbolt ECO" fastener as the accused product and various "Stanley Installation Tools" (e.g., BLC40PB-35, LB45PT-70 NeoBolt® Tool) as instrumentalities used to perform the accused method. (Compl. ¶¶ 29, 37).
Functionality and Market Context
- The complaint alleges the Avbolt ECO is a "vibration resistant blind fastener" where a sleeve is swaged onto a mandrel during installation. (Compl. ¶30). A central allegation is that, like Plaintiff's commercial embodiment, the "Avbolt ECO does not fracture off the mandrel," which is said to create a "corrosion resistant blind fastener." (Compl. ¶30). The complaint includes a side-by-side comparison image of Plaintiff's BOMTail product and the accused Avbolt ECO, suggesting they are direct functional and market competitors. (Compl. ¶29).
- Plaintiff alleges that Defendants are marketing the Avbolt ECO to its customers, specifically naming Nextracker, for use in solar panel installations. (Compl. ¶38). Documentation, including product datasheets and operating manuals, allegedly instructs users to install the Avbolt ECO using Stanley tools. (Compl. ¶¶ 32, 37).
IV. Analysis of Infringement Allegations
’358 Patent Infringement Allegations (Claim 1)
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A blind fastener comprising: a sleeve comprising a first sleeve end, a second sleeve end, a cavity extending from the first sleeve end to the second sleeve end; | The Avbolt ECO product is alleged to be a blind fastener that includes a sleeve with two ends and an internal cavity. A photograph of the purported sleeve is provided. (Compl. ¶51). | ¶51 | col. 3:62-66 |
| and a mandrel configured to be at least partially received by the cavity of the sleeve, the mandrel comprising a first mandrel end...comprising an enlarged portion...a second mandrel end comprising a pull region, and a shank region... | The Avbolt ECO is alleged to include a mandrel with an enlarged head at one end, a grooved pull region at the other, and a shank in between. Photographs identify these features on the accused product. (Compl. ¶¶ 52-54). | ¶¶52-54 | col. 4:5-15 |
| wherein the pull region comprises an axial length no greater than 4 times a diameter of the shank region | The complaint alleges that based on measurements, the Avbolt ECO's pull region has a length of ~11.23mm and its shank region has a diameter of ~8.32mm, yielding a ratio of ~1.35, which is less than 4. A table and annotated diagram are provided to support this allegation. (Compl. ¶55). | ¶55 | col. 4:30-39 |
| and is configured to be engaged by an installation tool. | The Avbolt ECO's pull region is alleged to be designed for engagement by Stanley installation tools, as shown in promotional materials. A still from a promotional video depicts a tool's collet engaging the pull region. (Compl. ¶56). | ¶56 | col. 4:27-30 |
’358 Patent Infringement Allegations (Claim 16)
| Claim Element (from Independent Claim 16) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| inserting a first mandrel end of a blind fastener into a bore in a structure, the blind fastener comprising [structure of Claim 1] | The complaint alleges that installing the Avbolt ECO requires inserting it into a workpiece, and that the product has the structure recited in the claim. A still from a promotional video shows the fastener being inserted. (Compl. ¶69). | ¶¶69-70 | col. 6:11-13 |
| engaging a collet of the installation tool with the pull region of the blind fastener; | Users are allegedly instructed to use a Stanley tool whose collet engages the pull region of the Avbolt ECO. An annotated diagram from a promotional video illustrates the tool's collet engaging the fastener. (Compl. ¶71). | ¶71 | col. 6:14-16 |
| ...forcibly contacting the second sleeve end...with an anvil of the installation tool and moving the pull region distal from the second sleeve end... | The complaint alleges the installation process involves the tool's anvil pushing against the sleeve while the collet pulls the mandrel's pull region. A video still depicts this pulling action. (Compl. ¶72). | ¶72 | col. 6:17-22 |
| ...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... | The installation process is alleged to result in the deformation of the sleeve to form a blind-side head and the swaging of the sleeve onto the mandrel shank. A product diagram shows the area of "Swaging." (Compl. ¶74). | ¶¶73-74 | col. 6:46-53 |
Identified Points of Contention
- Scope Questions: A central dispute may concern the precise definitions and boundaries of the "pull region" and "shank region." The application of the critical "no greater than 4 times a diameter" limitation depends entirely on where these regions are determined to begin and end, and which specific diameter of the potentially non-uniform shank is used for the calculation.
- Technical Questions: The complaint's infringement theory for the dimensional limitation rests on its own measurements of the accused product. (Compl. ¶55). A key factual question will be whether these measurements are accurate and representative of the accused products as manufactured and sold, a matter that will require discovery and expert analysis.
V. Key Claim Terms for Construction
The Term: "pull region" (Claim 1, 16)
- Context and Importance: This term is critical because its "axial length" is the numerator in the claim's dispositive dimensional ratio. The definition of the region's start and end points directly controls whether the accused product infringes this limitation. Practitioners may focus on this term because the plaintiff's infringement read depends on the specific boundaries it has assumed for its measurements. (Compl. ¶55).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states the pull region "can comprise at least one of a generally smooth region, an annular shoulder, a groove, and a bore," suggesting a functional definition covering various features that an installation tool could engage. (’358 Patent, col. 4:53-58).
- Evidence for a Narrower Interpretation: The patent figures depict the pull region (120) as a distinct grooved section at the end of the mandrel, visually separate from the shank region (122). (’358 Patent, Fig. 1). A party could argue the term is limited to this specific, grooved structure shown in the preferred embodiment.
The Term: "diameter of the shank region" (Claim 1, 16)
- Context and Importance: This term provides the denominator for the 4x ratio. The shank region may have multiple diameters (e.g., if it is grooved or tapered), and the claim's satisfaction depends on which diameter is selected for the calculation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is simple—"a diameter"—which could be construed to mean any measurable diameter within the defined shank region. If any such diameter satisfies the ratio, the claim might be met.
- Evidence for a Narrower Interpretation: The specification provides slightly ambiguous guidance, stating the diameter "can be the major diameter (e.g., root) of the shank region." (’358 Patent, col. 4:37-39). The parenthetical "(e.g., root)" could be used to argue that the "root diameter" of any grooves is the proper measurement, which is typically smaller than the "major diameter," thereby making the 4x ratio harder to satisfy.
VI. Other Allegations
Indirect Infringement
- The complaint alleges both induced and contributory infringement. The inducement theory is based on Defendants' alleged provision of product datasheets, user manuals, and promotional videos that instruct customers on how to use the Avbolt ECO fasteners with Stanley tools in a manner that performs the steps of method claim 16. (Compl. ¶¶ 66, 77).
Willful Infringement
- Willfulness is alleged based on Defendants' continued infringement after receiving actual notice of the ’358 patent via a letter dated May 15, 2025. (Compl. ¶¶ 60, 80).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim construction and metrology: how will the court define the precise boundaries of the "pull region" and "shank region," and which diameter of the shank is legally relevant for the "no greater than 4 times a diameter" limitation? The outcome of this construction will likely determine the infringement analysis for the asserted claims.
- A central evidentiary question will be one of factual verification: are the plaintiff’s pre-discovery measurements of the accused Avbolt ECO fastener's dimensions, presented as fact in the complaint, accurate and representative of the product line? The dispute may turn on competing expert analyses of the accused product's actual geometry.