DCT
1:18-cv-01889
NEXTracker Inc v. Sunlink Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: NEXTracker, Inc. (Delaware)
- Defendant: SunLink Corporation (Delaware)
- Plaintiff’s Counsel: Fish & Richardson P.C.
- Case Identification: 1:18-cv-01889, D. Del., 11/28/2018
- Venue Allegations: Venue is asserted to be proper in the District of Delaware because the Defendant, SunLink Corporation, is a Delaware corporation.
- Core Dispute: Plaintiff alleges that Defendant’s TechTrack line of single-axis solar trackers infringes two patents related to the mechanical support structures and clamping mechanisms for rotating solar panel arrays.
- Technical Context: The dispute is in the utility-scale solar power industry, where solar trackers rotate photovoltaic panels to follow the sun, significantly increasing energy capture efficiency over fixed-tilt systems.
- Key Procedural History: The complaint alleges that Defendant gained knowledge of the technology underlying the ’669 Patent during failed merger negotiations in September 2015 with the patent's original assignee, Optimum Tracker. It further alleges that Optimum Tracker later sent a letter to the Defendant regarding the published U.S. patent application that would become the ’669 Patent. These allegations of pre-suit knowledge form the basis for the willfulness claim.
Case Timeline
| Date | Event |
|---|---|
| 2012-12-10 | Earliest Priority Date for U.S. Patent No. 9,970,686 |
| 2013-01-01 | NEXTracker founded (approximate year) |
| 2013-01-01 | SunLink's Director of Products allegedly visits NEXTracker (approximate year) |
| 2014-11-05 | Priority Date for U.S. Patent No. 9,806,669 |
| 2015-09-01 | SunLink allegedly reviews ’669 Patent technology during merger talks |
| 2016-09-08 | U.S. National Stage Application for ’669 Patent filed |
| 2016-09-12 | SunLink allegedly offered accused products at Solar Power Int'l 2016 |
| 2017-10-31 | U.S. Patent No. 9,806,669 issues |
| 2018-05-15 | U.S. Patent No. 9,970,686 issues |
| 2018-07-10 | SunLink allegedly offered accused products at Intersolar 2018 |
| 2018-11-28 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,806,669 - "Single-Axis Follower Support System for a Solar Collector," issued October 31, 2017
The Invention Explained
- Problem Addressed: The patent describes a problem in prior art single-axis solar trackers where the horizontal axis of rotation is necessarily located a significant distance away from the center of gravity of the solar panel platform. This distance increases the mechanical effort required to rotate the array, making the system less efficient. (’669 Patent, col. 1:43-62).
- The Patented Solution: The invention proposes a unique bearing system that brings the axis of rotation closer to the panels' center of gravity. This is achieved through a bearing with a rotatable part that includes both a housing for the main support beam and a curved guide rail extending below the housing. This rotatable part moves along rolling members (e.g., ball bearings) that are fixed to a stationary base anchored to the ground. (’669 Patent, Abstract; col. 2:5-24). This configuration, depicted in Figure 2, allows for a more balanced and mechanically efficient rotation. (’669 Patent, FIG. 2).
- Technical Importance: This design purports to reduce the torque required to rotate the solar array, which can lower the power requirements and cost of the drive system, a critical consideration in large-scale solar installations. (’669 Patent, col. 2:1-4).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 1 (Compl. ¶33).
- The essential elements of independent claim 1 include:
- A fixed structure for anchorage to a ground.
- A platform to support a solar collector, fastened on a horizontal central beam.
- The beam is rotatably mounted on the fixed structure via at least one bearing.
- The bearing comprises a "rotatable part" with a housing for the beam and a "guide rail" with a circular-arc shape.
- The bearing also comprises a "base" held on the fixed structure, onto which "rolling members" are fastened.
- These rolling members are mounted to "roll in the guide rail of the rotatable part."
- The complaint reserves the right to assert other claims (Compl. ¶32).
U.S. Patent No. 9,970,686 - "Balanced Solar Tracker Clamp," issued May 15, 2018
The Invention Explained
- Problem Addressed: The patent addresses the need for tracking systems that are "fully adjustable in at each of the pillars," suggesting a focus on accommodating real-world construction imperfections and simplifying field installation. (’686 Patent, col. 2:25-34).
- The Patented Solution: The invention is a tracker apparatus with a specific mechanical configuration designed for robustness and adjustability. Key features include a "drive mount capable of accommodating construction tolerances in at least three-axes" and a clamp assembly with a specially shaped housing. This housing's opening contains distinct inner regions that act as mechanical stops, defining the rotational limits for the main torque tube. (’686 Patent, Claim 8; col. 6:1-6).
- Technical Importance: Providing adjustability in multiple axes at the drive mount can compensate for misalignments in pier installation, a common and costly problem in large solar fields, thereby speeding up construction and reducing labor costs. (’686 Patent, col. 5:65-col. 6:6).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 8 (Compl. ¶57).
- The essential elements of independent claim 8 include:
- A first pier with a first pivot device and a second pier with a drive mount.
- The drive mount is "capable of accommodating construction tolerances in at least three-axes."
- A torque tube is operably disposed on the piers.
- A clamp is configured around the torque tube to support a solar module.
- A clamp assembly with a housing coupled to the torque tube, where the housing has an opening with a "first inner region" and a "second inner region" that act as first and second stops for the torque tube's movement in first and second radial directions.
- The complaint reserves the right to assert other claims (Compl. ¶56).
III. The Accused Instrumentality
Product Identification
- The accused product is the "TechTrack Distributed solar tracker" sold by SunLink (Compl. ¶33, ¶57).
Functionality and Market Context
- The TechTrack is a single-axis solar tracker system designed for utility-scale solar power plants (Compl. ¶1). The complaint alleges that SunLink markets, sells, and provides installation manuals and engineering services for these trackers in the United States (Compl. ¶¶ 16, 18, 24, 26).
- The complaint alleges that the accused product incorporates a "Balanced Row Bearing Design" that is central to the infringement allegations for the ’669 Patent (Compl. ¶33). A screenshot from a datasheet shows the labeled "Pier", "Pivot Device", and "Drive Mount" components accused of infringing the ’686 Patent (Compl. ¶¶ 59-60). The complaint further alleges that SunLink is a "follower" in the solar tracker market, where NEXTracker is a "leader" (Compl. ¶1, ¶15).
IV. Analysis of Infringement Allegations
’669 Patent Infringement Allegations
The complaint uses an annotated screenshot from a SunLink marketing video to show how the accused product allegedly meets the limitations of the bearing element. The screenshot labels components of the accused bearing as the "Rotatable Part," "Guide Rail," "Housing," "Base," and "Fixed Rolling Members" (Compl. ¶37, p. 12).
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a fixed structure for anchorage to a ground | The accused TechTrack trackers have "vertical piers that are fixed and are for anchorage to a ground." | ¶35 | col. 4:21-26 |
| a platform configured to support at least one solar collector, said platform being fastened on at least one horizontal central beam rotatably mounted on the fixed structure... | The accused trackers contain a platform for a solar collector, which is fastened to a "Horizontal Beam and Axis" that is rotatably mounted on the fixed structure. | ¶36 | col. 4:30-36 |
| ...inside at least one bearing fastened on the fixed structure, wherein at least one bearing comprises (i) a rotatable part including...a housing for receiving the horizontal central beam and...a guide rail presenting a circular-arch shape...said guide rail extending below said housing and (ii) a base held on the fixed structure... | The accused trackers allegedly contain a bearing with a rotatable part, housing, guide rail, and base. | ¶37 | col. 4:50-51 |
| ...and onto which are fastened rolling members, said rolling members being mounted so as to roll in the guide rail of the rotatable part. | The accused bearing allegedly has "Fixed Rolling Members" that are mounted on the base and roll in the guide rail of the rotatable part. | ¶37 | col. 4:52-55 |
- Identified Points of Contention:
- Technical Question: The central dispute may concern the nature of the "rolling members." The complaint alleges the accused "Fixed Rolling Members" "roll in the guide rail" (Compl. ¶37), but the primary evidence is a static, labeled screenshot. The case may require detailed evidence and expert testimony to establish whether the accused components perform the specific "rolling" function as claimed, or if they operate via a different mechanism, such as sliding.
- Scope Question: The patent describes the guide rail as a "through slot" in one embodiment ('669 Patent, col. 2:60-62). The litigation may raise the question of whether the claims are limited to this specific "through slot" structure or can be read more broadly to cover the design of the accused product's guide rail.
’686 Patent Infringement Allegations
The complaint uses annotated screenshots from a product datasheet to map features of the accused tracker to claim limitations. One image labels the "First Pier" and "Second Pier" and their associated "Pivot Device" and "Drive Mount" (Compl. ¶¶ 59-60, pp. 15-16).
| Claim Element (from Independent Claim 8) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a first pier comprising a first pivot device; [and] a second pier comprising a drive mount... | The accused trackers contain a first pier with a first pivot device and a second pier with a drive mount. | ¶59, ¶60 | col. 19:8-10 |
| ...the drive mount capable of accommodating construction tolerances in at least three-axes | The accused trackers contain a drive mount that is allegedly capable of this three-axis accommodation. | ¶60 | col. 19:11-13 |
| ...a clamp assembly comprising a housing coupled to the torque tube...the housing comprising an opening having a major plane normal to a length of the torque tube, the opening comprising a first inner region and a second inner region... | The accused trackers contain a clamp assembly with a housing coupled to the torque tube, and the housing has an opening with a first inner region and a second inner region. | ¶63 | col. 19:38-44 |
| ...the first inner region acts as a first stop for movement of the torque tube...and the second inner region acts as a second stop... | The accused trackers contain a clamp assembly where the first inner region acts as a first stop and the second inner region acts as a second stop. | ¶63 | col. 19:44-50 |
- Identified Points of Contention:
- Scope Question: A critical issue for the court will be construing the term "capable of accommodating construction tolerances in at least three-axes." The complaint asserts this functionality but does not detail how the accused product achieves it (Compl. ¶60). The patent itself links this capability to a "spherical bearing" ('686 Patent, col. 6:21-23), which may narrow the scope of this functional language.
- Technical Question: Proving the existence and function of the "first inner region" and "second inner region" as stops may be an evidentiary challenge. The complaint includes a labeled image of the "First Inner Region" but explicitly states the "Second Inner Region (not visible in image)" (Compl. ¶63, p. 19), suggesting that demonstrating this element's presence and function will require more than surface-level product analysis.
V. Key Claim Terms for Construction
For U.S. Patent 9,806,669
- The Term: "rolling members being mounted so as to roll in the guide rail" (Claim 1)
- Context and Importance: This phrase describes the core mechanical action of the patented bearing. The infringement case hinges on whether the accused product's bearing operates in this specific manner. Practitioners may focus on this term because the distinction between "rolling" and other forms of movement, like sliding or gliding, could be case-dispositive.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself does not specify the type of rolling member, referring generally to "rolling members." This could support an interpretation that covers various components that perform a rolling function. (’669 Patent, col. 7:11-14).
- Evidence for a Narrower Interpretation: The specification repeatedly refers to the rolling members as being of the "ball bearing type, needle bearing type or roller bearing type" and rolling within a "through slot." (’669 Patent, col. 4:52-55; col. 2:60-62). A defendant may argue these specific embodiments limit the term to traditional bearing structures within a defined slot, not just any contact that involves rotation.
For U.S. Patent 9,970,686
- The Term: "drive mount capable of accommodating construction tolerances in at least three-axes" (Claim 8)
- Context and Importance: This functional language is a key feature of the invention, addressing the practical challenges of field installation. The entire case could turn on whether the accused product's drive mount is found to possess this specific multi-axis adjustability.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim does not define the "three-axes," leaving it open to a potentially broad interpretation covering any combination of three-dimensional adjustments (e.g., vertical, lateral, and rotational). The patent also discusses adjustability in general terms, such as being "fully adjustable in at each of the pillars." (’686 Patent, col. 2:28-29).
- Evidence for a Narrower Interpretation: The specification suggests that this capability is achieved via a "spherical bearing" which "allows for a construction tolerance." (’686 Patent, col. 6:21-23). A defendant could argue that the term should be limited to the specific range of motion provided by a spherical bearing, rather than any generic three-axis adjustment mechanism.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for both patents. Inducement is premised on SunLink allegedly marketing the accused trackers and providing instructions, installation manuals, and engineering services that direct customers to use the products in an infringing manner (Compl. ¶¶ 21, 24, 43, 69). The complaint alleges contributory infringement by asserting SunLink sells a collection of components that are especially made for infringing use and are not common components suitable for non-infringing use (Compl. ¶¶ 39-40, 65-66).
- Willful Infringement: Willfulness is alleged for both patents based on extensive claims of pre-suit knowledge. The complaint asserts that SunLink "reviewed and analyzed the technology underlying the '669 Patent" during failed merger negotiations with the original assignee in 2015 (Compl. ¶27). It further alleges that the original assignee sent a letter to SunLink informing it of the published patent application that matured into the ’669 Patent (Compl. ¶29). Finally, it alleges SunLink researches NEXTracker's products and IP in the regular course of business (Compl. ¶30).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of pre-suit knowledge and intent: The allegations that SunLink analyzed the patented technology during failed merger talks and later received a letter regarding the patent application create a significant factual basis for the willfulness claim. The resolution of this issue will heavily influence potential damages if infringement is found.
- A key question will be one of functional scope: Can the phrase "capable of accommodating construction tolerances in at least three-axes" from the ’686 patent be proven to read on the accused drive mount? The plaintiff will need to provide substantial evidence defining this capability and showing that the accused product performs it.
- A third core issue will be one of mechanical operation: Does the accused product's "Balanced Row Bearing Design" function in the manner required by the ’669 patent? Specifically, the court's determination will likely depend on whether the evidence shows the accused components "roll in the guide rail," as claimed, or if there is a fundamental mismatch in their mechanical action.