DCT
1:20-cv-02356
Somero Enterprises Inc v. Ligchine Intl Corp
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Somero Enterprises, Inc. (Delaware)
- Defendant: Ligchine International Corporation (Indiana)
- Plaintiff’s Counsel: Barnes & Thornburg LLP; Honigman LLP
- Case Identification: 1:20-cv-02356, S.D. Ind., 09/17/2020
- Venue Allegations: Venue is alleged to be proper in the Southern District of Indiana because the defendant, Ligchine, is an Indiana corporation with its principal place of business in the district, and thus resides there.
- Core Dispute: Plaintiff alleges that Defendant’s "SpiderScreed" line of concrete screeding machines infringes a patent related to wheeled, laser-guided concrete screeding technology.
- Technical Context: The technology concerns automated machines used in construction to level and finish large surfaces of uncured concrete, a process known as screeding.
- Key Procedural History: The complaint notes that Plaintiff provided Defendant with actual notice of the patent and alleged infringement via a letter dated July 30, 2020. Subsequent to the filing of this complaint, an Inter Partes Review (IPR) was initiated against the '366 Patent (IPR2024-00051), which resulted in a final written decision cancelling all asserted claims (1-15). This post-complaint development renders the patent unenforceable.
Case Timeline
| Date | Event |
|---|---|
| 2004-07-26 | '366 Patent Priority Date |
| 2011-10-18 | '366 Patent Issue Date |
| 2019-01-22 | Accused SpiderScreed Product Introduced |
| 2020-07-30 | Plaintiff sends notice letter to Defendant |
| 2020-09-17 | First Amended Complaint Filing Date |
| 2023-10-24 | IPR filed against '366 Patent (IPR2024-00051) |
| 2025-03-03 | U.S. Patent Office cancels claims 1-15 of '366 Patent |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,038,366 - "Wheeled Concrete Screeding Device"
- Patent Identification: U.S. Patent No. 8,038,366, "Wheeled Concrete Screeding Device," issued October 18, 2011.
The Invention Explained
- Problem Addressed: The patent's background section describes the considerable manual labor required to spread and level uncured concrete in areas where large, automated screeding machines cannot be used, which is costly and labor-intensive (’366 Patent, col. 1:38-47).
- The Patented Solution: The invention is a smaller, "walk-behind" power rake or plow apparatus for striking-off uncured concrete (’366 Patent, col. 1:54-58). As depicted in Figure 1, it consists of a wheeled unit (12) that moves through the concrete, and a plow head assembly (14) that follows behind. This assembly includes a "grade establishing element" (e.g., a plow) that is automatically adjusted to a desired height by a laser receiver (20), and a separate "vibratable member" that smoothes and compacts the concrete at the established grade (’366 Patent, col. 1:59-67).
- Technical Importance: This approach sought to bring the accuracy and labor-saving benefits of laser-guided automation to smaller-scale concrete projects that previously relied on manual methods (’366 Patent, col. 5:1-6).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2-5 (’366 Patent, col. 25:8-38; Compl. ¶21).
- Independent Claim 1 recites a wheeled concrete screeding device with the following essential elements:
- A wheeled unit with at least two wheels, movable through uncured concrete.
- A screed head supported at the rear of the wheeled unit, comprising a grade establishing element and a vibratable member.
- The grade establishing element is vertically adjustable in response to a signal from a laser receiver on the screed head.
- The vibratable member is adjustably attached to the rear of the grade establishing element and "at least partially floats" on and is supported by the struck-off surface of the uncured concrete.
- The complaint reserves the right to assert additional claims (’366 Patent, Compl. ¶21).
III. The Accused Instrumentality
Product Identification
- The accused instrumentality is the Ligchine "SpiderScreed" machine (’366 Patent, Compl. ¶14). A photograph of the machine is provided in the complaint (’366 Patent, Compl. ¶15).
Functionality and Market Context
- The complaint alleges the SpiderScreed is a "laser-guided concrete screed" designed for "upper deck concrete and slab-on-grade screeding applications" (’366 Patent, Compl. ¶13, p. 5).
- Based on product literature cited in the complaint, the SpiderScreed features an "automatic laser leveling" system with two receiver "eyes," and a screed head that includes a 10-foot auger (’366 Patent, Compl. p. 8). The complaint includes a photograph showing the accused machine operating on uncured concrete, with its wheels moving on the subgrade and its screed head leveling the concrete (’366 Patent, Compl. p. 5).
IV. Analysis of Infringement Allegations
'366 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A wheeled concrete screeding device for screeding uncured concrete... | The SpiderScreed is a "wheeled concrete screeding device for screeding uncured concrete." | ¶22, p. 5 | col. 25:8-12 |
| a wheeled unit having at least two wheels for movably supporting a frame portion of said wheeled unit...wherein said wheeled unit is movable through uncured concrete in a screeding direction; | The SpiderScreed is a "wheeled unit having at least two wheels for movably supporting a frame portion...movable through uncured concrete in a screeding direction." | ¶22, p. 5 | col. 25:13-18 |
| a screed head supported at said rearward end of said frame portion and following behind said wheeled unit...said screed head comprising a grade establishing element and a vibratable member; | The SpiderScreed has "a screed head supported at said rearward end of said frame portion...comprising a grade establishing element and a vibratable member." | ¶22, p. 5 | col. 25:19-23 |
| wherein said grade establishing element is generally vertically adjustable responsive to a signal from a laser receiver disposed at said screed head to establish a struck-off surface of the uncured concrete at a desired grade... | The SpiderScreed has a grade establishing element that is "generally vertically adjustable responsive to a signal from a laser receiver" to establish a desired grade. | ¶22, p. 6 | col. 25:24-29 |
| wherein said vibratable member is adjustably attached at a rearward end of said grade establishing element and wherein said vibratable member at least partially floats behind said grade establishing element on the struck-off surface... | The SpiderScreed has a "vibratable member is adjustably attached at a rearward end" and "at least partially floats behind said grade establishing element on the struck-off surface." | ¶22, p. 6 | col. 25:30-38 |
- Identified Points of Contention:
- Scope Questions: The complaint alleges the SpiderScreed's auger meets the "grade establishing element" limitation (Compl. p. 8). A potential dispute is whether the term "grade establishing element," often described in the patent as a "plow member" (’366 Patent, col. 6:18), can be construed to read on the accused product's auger. While dependent claim 3 explicitly adds an auger, the question for claim 1 is whether an auger falls within the scope of the broader term.
- Technical Questions: Claim 1 requires the "vibratable member" to "at least partially float" on the struck-off concrete. The complaint supports this with a close-up photograph of the screed head (Compl. p. 6). However, a key factual question is what evidence demonstrates that the accused member performs this specific "floating" function, which implies a particular physical interaction and degree of support from the concrete itself, rather than simply being dragged at a fixed position relative to the main unit.
V. Key Claim Terms for Construction
- The Term: "at least partially floats"
- Context and Importance: This term defines the functional relationship between the vibratable member, the grade establishing element, and the uncured concrete. The infringement analysis for claim 1 hinges on whether the accused device's vibratable member operates with the specific degree of freedom and support from the concrete that is connoted by "floats." Practitioners may focus on this term because it describes a behavior, not just a structure, and its meaning will likely determine whether the accused product's operation aligns with the claim.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes an embodiment where the attachment links are "pivotally attached," allowing the vibrating member to "freely float relative to the plow" and "rest on the forms" (’366 Patent, col. 13:12-14). This could suggest that any non-rigid connection that allows the member to rest on a surface (either the forms or the concrete) satisfies the "floating" limitation.
- Evidence for a Narrower Interpretation: The claim language itself requires the member to float "on the struck-off surface of the uncured concrete" and be "at least partially supported at the struck-off surface" (’366 Patent, col. 25:32-37). This language, along with the abstract, could support a narrower definition requiring the concrete itself, not just external forms, to provide the support and define the member's vertical position. The complaint alleges this specific behavior with a photograph showing the member on concrete (Compl. p. 6).
VI. Other Allegations
- Indirect Infringement: The complaint makes a general allegation of infringement under 35 U.S.C. § 271 et seq. but does not plead specific facts to support claims of induced or contributory infringement, such as allegations that Defendant instructs users to perform infringing acts or sells a non-staple component for infringing use (Compl. ¶24).
- Willful Infringement: The complaint alleges that Defendant’s infringement has been willful and deliberate based on its continued infringing activities after receiving Plaintiff's notice letter of July 30, 2020 (Compl. ¶17, ¶26). This alleges pre-suit knowledge of the patent and the alleged infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
At the time of its filing, this case presented standard questions of patent infringement. However, subsequent events have fundamentally altered its trajectory.
- A central question would have been one of technical and functional scope: Could Plaintiff prove that the accused "SpiderScreed," with its auger-based design, practices the "grade establishing element" limitation, and more critically, that its vibratable member performs the specific "floating" action on the surface of uncured concrete as required by claim 1?
- The dispositive issue is now procedural and external to the complaint’s original merits: the cancellation of all asserted claims (1-15) in a subsequent Inter Partes Review renders the patent unenforceable. This development, occurring years after the complaint was filed, effectively moots the infringement action and highlights the significant and often case-ending impact of parallel validity challenges at the U.S. Patent and Trademark Office.