DCT
4:20-cv-03557
Pave Lock Plus II LLC v. Erosion Prevention Products LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Pave/Lock/Plus II, LLC d/b/a Paveloc Plus (Texas)
- Defendant: Erosion Prevention Products LLC and Lee A. Smith (Texas)
- Plaintiff’s Counsel: Patterson + Sheridan LLP
- Case Identification: 4:20-cv-03557, S.D. Tex., 10/16/2020
- Venue Allegations: Venue is asserted based on Defendants' residence within the district and because a substantial part of the events giving rise to the claims, including allegations of infringement made by Defendants against Plaintiff, are alleged to have occurred in the district.
- Core Dispute: Plaintiff seeks a declaratory judgment that its concrete revetment blocks do not infringe Defendant's patent related to interlocking erosion control blocks, and further alleges tortious interference by Defendants.
- Technical Context: The technology concerns articulated concrete block systems used to armor shorelines and waterway beds against soil erosion, a significant component of civil engineering and public works construction projects.
- Key Procedural History: The complaint states this action was prompted by Defendant Smith, an inventor on the patent-in-suit, representing to third parties, including Plaintiff’s potential customers, that Plaintiff was infringing the patent. The complaint also alleges that Defendants have engaged in false marking by affixing an expired patent number to their own products.
Case Timeline
| Date | Event |
|---|---|
| 2009-02-03 | ’435 Patent Priority Date |
| 2012-02-28 | ’435 Patent Issue Date |
| 2015-02-06 | U.S. Patent No. 5,556,228 (allegedly on Def. label) expires |
| 2020-06-22 | Date of product run for Defendant's allegedly mismarked product |
| 2020-09-21 | Plaintiff's counsel sends letter to Defendants |
| 2020-10-16 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,123,435 - "INTERLOCKING REVETMENT BLOCK WITH ARRAY OF VEGETATION HOLES"
The Invention Explained
- Problem Addressed: The patent background describes the challenge of creating erosion control blocks that can withstand high-velocity water currents without being dislodged ('435 Patent, col. 1:31-35). While holes for vegetation can help anchor blocks to the soil, these same holes can create undesirable hydraulic lift forces if vegetation is sparse or absent ('435 Patent, col. 2:1-13). Additionally, the blocks must be designed for practical installation, implying constraints on weight and features for manual handling ('435 Patent, col. 2:20-35).
- The Patented Solution: The invention is an interlocking concrete block with a specific geometry of arms and sockets designed for both lateral and vertical stability between adjacent blocks ('435 Patent, Abstract). The design incorporates a specific array of five tapered holes within a central "core square," which are dimensioned and located to balance the need for vegetation growth, hydraulic stability, and providing grip points for a workman to lift and place the block ('435 Patent, col. 5:42-55; col. 2:56-63).
- Technical Importance: The design purports to offer an optimized solution that is cost-effective, easy to install, and certifiable for hydraulic stability under severe flow conditions, a key requirement for winning erosion control project contracts ('435 Patent, col. 2:40-52).
Key Claims at a Glance
- The complaint identifies independent claims 1 and 9 as being at issue (Compl. ¶ 29-30).
- Independent Claim 1's essential elements include:
- A block body with at least two interlocking arms and two corresponding sockets.
- A plurality of holes through the block body.
- Wherein the holes are tapered from top to bottom.
- Wherein the diameter of the bottom opening of each hole is the same.
- Wherein the diameter of the top opening of each hole are not all the same.
- Independent Claim 9's essential elements include:
- A block body with full-thickness arms and full-depth sockets.
- A "core square" with a specific geometric relationship to the block's edges and sockets.
- Five holes located in the core square with specific positions relative to the square's diagonals.
- Wherein the hole diameters on one surface are all the same, while on the other surface, three holes have a diameter different from the other two.
III. The Accused Instrumentality
Product Identification
The complaint identifies the products at issue as Plaintiff Paveloc’s "revetment products including articulated block units" (Compl. ¶13) and "revetment blocks" (Compl. ¶32). Specific product names are not provided.
Functionality and Market Context
- The complaint offers minimal technical description of Paveloc's products, noting only that they are used for erosion control and were supplied under a subcontract for a project with the Fort Bend County Levee Improvement District No. 2 (Compl. ¶10, 13).
- The primary technical allegation is a negative one: that Paveloc’s products do not possess the specific combination of hole-geometry features required by the final limitation of Claim 1 of the ’435 Patent (Compl. ¶32).
- The complaint alleges that Defendants are harming Paveloc's business relationships by telling customers its products infringe (Compl. ¶14, 18). As evidence of Defendants' alleged bad faith, the complaint includes a description of a label affixed to Defendants' own products, which is said to be falsely marked with an expired patent number (Compl. ¶21-22).
IV. Analysis of Infringement Allegations
As this is a complaint for a declaratory judgment of non-infringement, the analysis focuses on Paveloc's denial of infringement. The complaint provides a specific basis for non-infringement of Claim 1 but only a general denial for Claim 9.
Claim Chart Summary:
'435 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A revetment block, comprising: said block having a body with a thickness defined by a distance between a top surface and a bottom surface of the body of said block, and said block having a plurality of side edges; | The complaint does not provide sufficient detail for analysis of this element of Paveloc's product. | N/A | col. 8:15-19 |
| at least two arms, each arm extending from a respective side edge of the body of said block; each said arm having an enlarged end connected to a respective side edge by a narrowed neck portion; | The complaint does not provide sufficient detail for analysis of this element of Paveloc's product. | N/A | col. 8:20-24 |
| at least two sockets formed inwardly from respective side edges of the body of said block; each said socket having an enlarged cavity connected by a narrowed inlet to the respective side edge of the body of said block... | The complaint does not provide sufficient detail for analysis of this element of Paveloc's product. | N/A | col. 8:25-31 |
| a plurality of holes formed through the body of said block, wherein said holes are each tapered to flare out from the top surface... a diameter of a bottom opening of each said hole... is the same, and a diameter of a top opening of each said hole... are not all the same. | The complaint alleges that Paveloc’s revetment blocks do not have a plurality of holes with this specific combination of features regarding tapering and the relative diameters of the top and bottom openings. | ¶32 | col. 8:31-40 |
- Identified Points of Contention:
- Technical Question: The central factual dispute for Claim 1 is whether Paveloc's blocks meet all three sub-conditions of the final limitation: (1) tapered holes, (2) same-diameter bottom openings, and (3) different-diameter top openings. The complaint’s targeted denial raises the question of which of these specific features is allegedly missing from its products.
- Scope Question: For Claim 9, which recites a highly specific "core square" and a five-hole pattern, the infringement analysis will depend on whether the geometry of Paveloc's block can be mapped onto these precise structural limitations.
V. Key Claim Terms for Construction
The Term: "a diameter of a top opening of each said hole in the top surface of said block are not all the same" (Claim 1)
- Context and Importance: This term is the sole basis for the specific non-infringement argument articulated in the complaint (Compl. ¶32). The outcome of its construction could be dispositive. Practitioners may focus on this term because its interpretation will determine whether any minor variation suffices or if a material, functional difference is required.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue that the plain language "not all the same" is unambiguous and covers any deviation, including incidental manufacturing tolerances.
- Evidence for a Narrower Interpretation: The specification explains that the purpose of the different diameters is to create larger "finger holes" for a workman to grasp ('435 Patent, col. 6:29-48). This context may support an interpretation that "not all the same" requires a deliberate and functionally significant difference in diameter, such as the 2.0-inch and 2.5-inch examples provided in the preferred embodiment ('435 Patent, col. 6:20-24).
The Term: "core square" (Claim 9)
- Context and Importance: This term defines the area where the claimed five holes must be located. As a patentee-coined term, its definition is crucial for determining infringement of Claim 9.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself provides a definition, describing the "core square" by its boundaries relative to the block's side edges and the inner edges of the sockets ('435 Patent, col. 10:2-9). A party could argue this claim language is the sole determinant of the term's scope.
- Evidence for a Narrower Interpretation: The specification provides a more explicit definition, stating the "core square" is "that portion of the block that excludes the two arms 14 and 16 and the two sockets 12 and 18" ('435 Patent, col. 5:62-65). This could be used to argue that a block with a different arrangement of arms and sockets may not possess a "core square" as envisioned by the inventor.
VI. Other Allegations
- Indirect Infringement: Not applicable. The complaint seeks a declaration of non-infringement.
- Willful Infringement: Not applicable. The complaint does not allege willful patent infringement by Paveloc. It does allege that Defendants' actions related to the tortious interference claim were "willful, wanton, malicious" (Compl. ¶43), but this pertains to Defendants' alleged business conduct, not to a claim of patent infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
- A key evidentiary question will be one of product-to-claim mapping: Does Paveloc's product, as actually manufactured and sold, meet every limitation of the asserted claims? The dispute will likely focus on objective evidence regarding the precise geometry of the holes in Paveloc's blocks.
- A core issue will be one of definitional scope: How will the court construe the phrase "not all the same" in Claim 1? The case may turn on whether this requires a functionally significant difference in hole diameter, as suggested by the patent's specification, or if any measurable variation is sufficient to meet the limitation.
- A secondary question for the more complex Claim 9 will be one of structural identity: Does the geometric layout of Paveloc's block include the patent's specific definitions of a "core square" and the precise diagonal arrangement of five holes, or is there a fundamental mismatch in structure?