Danco LLC v. Hangzhou Great Star Industrial Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Danco, LLC (Delaware) and Edward Lenart (Michigan)
  • Defendant: Hangzhou Great Star Industrial Co., Ltd. (People's Republic of China)
  • Plaintiff's Counsel: Scheef & Stone, LLP
• Case Identification: 3:26-cv-01148, N.D. Tex., 08/27/2026
• Venue Allegations: Venue is alleged to be proper in any U.S. judicial district because the Defendant is a foreign corporation not resident in the U.S. Personal jurisdiction in the Northern District of Texas is alleged based on Defendant's acts of importing and selling the accused products in Texas.
• Core Dispute: Plaintiffs allege that Defendant's Kobalt-branded pry bars infringe two patents related to the design of pry bar assemblies.
• Technical Context: The technology is in the field of hand tools for construction and demolition, focusing on specific structural geometries intended to enhance strength and leverage while potentially reducing weight.
• Key Procedural History: The complaint alleges that the inventor and Danco entered into a Joint Development Agreement in 2018. During the prosecution of the '552 Patent, Plaintiffs allegedly submitted a declaration regarding the commercial success of their own product and evidence of competitor copying, specifically naming the accused Kobalt Pry Bar, to overcome prior art rejections. The parties reportedly engaged in settlement discussions between October 2024 and February 2026 after Defendant sent a letter asserting the '552 Patent was invalid.

Case Timeline

Date	Event
2018-09-05	Priority Date for '552 and '310 Patents
2018	Danco and Lenart enter Joint Development Agreement
Spring 2024	Danco becomes aware of accused HGS Pry Bars
2024-05-14	U.S. Patent No. 11,981,552 issues
2024-10-14	Hangzhou Great Star sends letter to Danco asserting invalidity
2024-10-01 - 2026-02-28	Parties engage in settlement discussions (range)
2025-07-29	U.S. Patent No. 12,371,310 issues
2026-08-27	First Amended Complaint filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,981,552 - "Pry Bar Assembly," issued May 14, 2024 ('552 Patent)

The Invention Explained

• Problem Addressed: The patent background identifies a need for tools used in deconstruction, such as removing framing, decking, and pulling apart structures held together by fasteners like nails '552 Patent, col. 1:40-44
• The Patented Solution: The invention is a pry bar with a uniquely designed claw section. This section features a plate and an "asymmetrically bowed" pry panel that is integrally formed with the plate '552 Patent, col. 3:20-22 The abstract and detailed description explain that this geometry, along with other features like an elongated crest, provides increased rigidity and strength, allowing the tool to be strong without being excessively heavy '552 Patent, abstract '552 Patent, col. 4:4-17
• Technical Importance: This design aims to improve the tool's strength-to-weight ratio, a critical factor for hand tools used in physically demanding construction and demolition tasks '552 Patent, col. 4:11-17

Key Claims at a Glance

• The complaint asserts independent claim 1 '552 Patent, col. 4:41
• The essential elements of independent claim 1 include:
  • A first section having a longitudinal axis in a first plane.
  • A second section comprising a first claw portion, which in turn comprises a first plate and a pry panel.
  • The first plate having lateral edges disposed in a second plane "substantially perpendicular to the first plane."
  • The pry panel being "asymmetrically bowed inwardly toward the first section from the first plate" and connected at both ends to the plate.
  • The first face of the plate comprising a tapered portion.
• The complaint also asserts dependent claims 2, 7, 9-11, 15-17, 19, 20, 22, 23, 25, 29, 33, 37, 46, and 47, and reserves the right to assert others 'Compl. ¶25

U.S. Patent No. 12,371,310 - "Pry Bar Assembly," issued July 29, 2025 ('310 Patent)

The Invention Explained

• Problem Addressed: As a continuation of the application leading to the '552 Patent, the '310 Patent addresses the same technical problem of creating an improved wrecking tool for deconstruction '310 Patent, col. 1:45-50
• The Patented Solution: The invention is described with slightly different terminology but claims a similar core structure. It claims a "handle section" and a "claw section" that includes a first claw portion and a pry panel '310 Patent, Claim 1 As in the '552 Patent, the key feature is that the pry panel is "asymmetrically bowed and extends inwardly from the first claw portion toward the handle section" '310 Patent, Claim 1 This suggests a focus on protecting variations of the same fundamental design concept.
• Technical Importance: The invention provides an alternative or refined configuration for a high-strength, lightweight pry bar, broadening the proprietary protection around the core design '310 Patent, col. 4:15-21

Key Claims at a Glance

• The complaint asserts independent claim 1 '310 Patent, col. 10:54
• The essential elements of independent claim 1 include:
  • A "handle section" with a longitudinal axis in a first plane.
  • A "claw section" extending from the handle, comprising a first claw portion and a pry panel.
  • The first claw portion having lateral edges in a second plane "substantially perpendicular to the first plane."
  • The pry panel being "asymmetrically bowed and extends inwardly from the first claw portion toward the handle section."
  • The pry panel being connected at two ends to the first claw portion.
• The complaint also asserts dependent claims 2, 3, 8-12, 15-19, 22, and 24-26, and reserves the right to assert others 'Compl. ¶32

III. The Accused Instrumentality

• Product Identification: The accused products are the Kobalt Pry Bar Model No. 66744 (Lowe's sku 5144457) and other similarly structured pry bars manufactured by Defendant Hangzhou Great Star Industrial Co., Ltd. (collectively "HGS Pry Bars") 'Compl. ¶1
• Functionality and Market Context: The complaint identifies the accused products as hand tools sold through retailers like Lowe's under the "Kobalt" store brand 'Compl. ¶17 It is alleged that Defendant manufactures these tools for sale in the U.S. market and that they are intended to compete directly with Plaintiffs' patented products ('Compl. ¶16; Compl. ¶18). The complaint includes an annotated version of Figure 2 from the '552 Patent to illustrate the allegedly infringing features of the accused tool 'Compl. ¶14 This visual aid from the complaint highlights a "First Section," a "First Claw Portion," and an "Asymmetrically Bowed Pry Panel" on a drawing of the tool 'Compl. ¶14

IV. Analysis of Infringement Allegations

The complaint alleges that the HGS Pry Bars literally infringe the asserted claims and references infringement analysis exhibits (Exhibits 3 and 4) that were not provided with the complaint document ('Compl. ¶24; Compl. ¶31). The following summary is based on the narrative allegations and claim language cited in the complaint.

'552 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a first section having a longitudinal axis in a first plane	The handle of the accused pry bar is alleged to be the "first section."	¶14	col. 3:2-5
a second section comprising a first claw portion	The working end of the accused pry bar is alleged to be the "second section" containing the "first claw portion."	¶14	col. 3:7-8
wherein the first claw portion comprises a first plate and a pry panel	The claw portion of the accused tool is alleged to comprise a plate structure and an integrated pry panel.	¶14	col. 3:20-22
wherein the first lateral edge and the second lateral edge are disposed in a second plane substantially perpendicular to the first plane	The side edges of the accused tool's claw portion are alleged to lie in a plane perpendicular to the handle's plane.	¶14	col. 3:14-15
wherein the pry panel is asymmetrically bowed inwardly toward the first section from the first plate...	The accused pry bar's panel is alleged to be "asymmetrically bowed" and oriented inward toward the handle.	¶14	col. 3:22-24
...and is connected at a first end to the first plate and at a second end to the first plate	The pry panel on the accused tool is alleged to be connected at two ends to the surrounding plate structure.	¶14	col. 4:57-59

'310 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a handle section comprising a longitudinal axis in a first plane	The handle of the accused pry bar is alleged to be the "handle section."	¶15	col. 3:8-11
a claw section extending from the handle section, the claw section comprising a first claw portion and a pry panel	The working end of the accused pry bar is alleged to comprise a claw section with a first claw portion and a pry panel.	¶15	col. 3:12-14
wherein the first lateral edge and the second lateral edge are disposed in a second plane substantially perpendicular to the first plane	The side edges of the accused tool's claw portion are alleged to be in a plane perpendicular to the handle.	¶15	col. 10:63-65
wherein the pry panel is asymmetrically bowed and extends inwardly from the first claw portion toward the handle section	The panel on the accused tool is alleged to be asymmetrically bowed and extend inward toward the handle.	¶15	col. 10:66-68
wherein the pry panel is connected at a first end to the first claw portion and at a second end to the first claw portion	The pry panel on the accused tool is alleged to be connected at two ends to the surrounding claw structure.	¶15	col. 11:1-3

• Identified Points of Contention: The infringement dispute may center on whether the accused product's structure meets the specific geometric limitations of the claims. The defendant has already signaled its intent to challenge the validity of the '552 Patent on grounds of indefiniteness, anticipation, and obviousness 'Compl. ¶19, suggesting that the interpretation and patentability of the claimed features, particularly the "asymmetrically bowed" panel, will be a primary focus of litigation. The prosecution history, in which Plaintiffs allegedly used the accused product as evidence of non-obviousness, may create complex arguments for both sides 'Compl. ¶¶20-21

V. Key Claim Terms for Construction

• The Term: "asymmetrically bowed" '552 Patent, Claim 1 '310 Patent, Claim 1

• Context and Importance: This term describes the core inventive feature highlighted in the complaint's annotated visual 'Compl. ¶14 Its definition will be central to both infringement and validity, as Defendant has already raised an indefiniteness challenge 'Compl. ¶19 Practitioners may focus on this term because its construction will likely determine whether the accused product's geometry falls within the scope of the claims.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The plain language "asymmetrically bowed" could be argued to cover any curvature that is not perfectly symmetrical. The patent describes the panel forming two legs of a triangle, which could be presented as just one example of asymmetry '552 Patent, col. 3:25-27
  • Evidence for a Narrower Interpretation: The specification provides a detailed embodiment where the pry panel forms "a short leg 54 and a long leg 56" with specific angular ranges relative to the plane of the aperture '552 Patent, col. 3:25-32 A defendant may argue that "asymmetrically bowed" should be limited to this specific configuration or is otherwise indefinite without such a limitation.

• The Term: "substantially perpendicular" '552 Patent, Claim 1 '310 Patent, Claim 1

• Context and Importance: This term defines the spatial relationship between the plane of the tool's handle and the plane of the claw's lateral edges. The degree of deviation allowed by "substantially" will be critical for determining literal infringement.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: Plaintiffs will likely argue that "substantially" is a term of approximation meant to account for manufacturing tolerances and minor deviations that do not alter the tool's fundamental structure or function.
  • Evidence for a Narrower Interpretation: The patent does not provide a specific angular range for "substantially." A defendant may argue that the context of a rigid tool for applying leverage implies a relationship that is very close to a true 90-degree angle to achieve the described function, and that significant deviation would fall outside the claim.

VI. Other Allegations

• Indirect Infringement: The complaint alleges inducement of infringement, stating that Defendant sells the HGS Pry Bars to retailers like Lowe's with the intent that they will then be sold to end-users for infringing uses ('Compl. ¶26; Compl. ¶33).
• Willful Infringement: Willfulness is alleged for both patents. For the '552 Patent, the complaint alleges Defendant has had actual notice since "at least October 14, 2024," the date of a letter from Defendant to Plaintiff regarding the patent 'Compl. ¶28 For the '310 Patent, the complaint alleges notice since its issue date, arguing Defendant had prior notice of the pending application from the ongoing dispute 'Compl. ¶35

VII. Analyst's Conclusion: Key Questions for the Case

1. Claim Construction & Validity: A core issue will be one of definitional scope and patentability: is the term "asymmetrically bowed" sufficiently definite under 35 U.S.C. § 112, and if so, can it be construed to cover the accused pry bar's specific geometry? The case will likely feature a significant battle over whether this feature was truly novel and non-obvious, especially given the defendant's pre-suit invalidity contentions 'Compl. ¶19
2. Prosecution History Estoppel & Inequitable Conduct: A key evidentiary and legal question will be the impact of the '552 Patent's prosecution history. Plaintiffs allegedly used the accused Kobalt pry bar as evidence of "competitor copying" to overcome a rejection 'Compl. ¶20 This raises the question of whether Plaintiffs' arguments now limit their infringement theories. Conversely, it provides Plaintiffs a strong basis for their willfulness claim and may complicate Defendant's non-infringement arguments.
3. Willfulness & Pre-Suit Knowledge: A central question for damages will be willfulness: can Plaintiffs establish that Defendant's alleged infringement was willful from the outset? The allegation that Defendant's own product was used to secure the patent's allowance 'Compl. ¶¶20-21 creates a unique factual predicate for arguing that Defendant had pre-suit knowledge of its infringing activity, or at minimum, was objectively reckless as to the risk of infringement once the patent issued.