DCT

1:26-cv-01675

Caster Concepts Inc v. Dorodo LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:26-cv-01675, W.D. Mich., 05/25/2026
  • Venue Allegations: Venue is alleged to be proper in the Western District of Michigan because Defendant DoRodo resides and has an established place of business in the district, and Defendant Schioppa is a foreign entity subject to personal jurisdiction in the district.
  • Core Dispute: Plaintiff alleges that Defendants' "Orbital wheel" casters infringe two patents related to a caster wheel assembly featuring a specific parabolic interface between the hub and the tread.
  • Technical Context: The technology concerns the design of industrial caster wheels, where the interface between a metal hub and a resilient tread is engineered to manage load-induced stresses, reduce wear, and improve performance.
  • Key Procedural History: The complaint states that Plaintiff notified Defendants of the asserted patents and the alleged infringement in writing beginning in September 2025 and continuing through March 2026, but the parties were unable to reach a resolution prior to the filing of the suit.

Case Timeline

Date Event
2012-12-11 Priority Date for '355 and '524 Patents
2014-10-21 '355 Patent Issued
2015-06-16 '524 Patent Issued
2025-XX-XX Plaintiff alleges it learned of Defendants' casters being sold in the U.S.
2025-09-XX Plaintiff notified Defendant DoRodo of the Asserted Patents by letter
2026-03-03 Plaintiff alleges Defendant Schioppa responded to the notification letter
2026-03-05 Plaintiff notified Defendants of their alleged infringement of the Asserted Patents
2026-05-26 Complaint Filing Date

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

U.S. Patent No. 8,863,355 - "Caster Wheel with Parabolic Tread-Hub Interface" (Issued Oct. 21, 2014)

The Invention Explained

  • Problem Addressed: The patent's background describes a trade-off in caster wheel design: hard wheels are durable but noisy and offer poor shock absorption, while soft, elastomeric treads are quieter and protect floors but are prone to failure from shear stresses and heat buildup, limiting their load capacity and lifespan ʼ355 Patent, col. 2:17-53
  • The Patented Solution: The invention is a caster wheel assembly where the metal hub has an "annularly dished concave region" with a specific parabolic cross-section that mates with a convex elastomeric tread ʼ355 Patent, abstract ʼ355 Patent, col. 3:1-15 This parabolic interface is engineered to convert destructive shear forces into compressive forces, which the elastomer can better withstand, thereby increasing load capacity and durability ʼ355 Patent, col. 3:16-29 The design is defined by the mathematical equation "y=A*x²" ʼ355 Patent, abstract
  • Technical Importance: This design seeks to achieve the high load capacity of a hard wheel while retaining the desirable characteristics of a soft wheel, such as quiet operation and floor protection, representing a significant engineering goal for industrial material handling equipment ʼ355 Patent, col. 2:54-63

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 Compl. ¶17
  • Essential Elements of Claim 1:
    • A hub with an outer rim section and an inner bearing section, with the rim section having an "annularly dished concave region" between two cylindrical lips.
    • A bearing and bushing assembly disposed within a counter-bore in the hub's bearing section.
    • A resilient elastomeric tread surrounding the rim, with a convex inner periphery that conforms to the hub's concave region in a "nested relationship."
    • The tread includes cylindrical pads that are in "direct surface-to-surface contact" with the hub's cylindrical lips.
    • The "annularly dished concave region" of the hub has a "parabolic OD cross-section" which is "defined by the equation y=A*x², where A is between 1.5 and 4."

U.S. Patent No. 9,056,524 - "Caster Wheel with Parabolic Tread-Hub Interface" (Issued June 16, 2015)

The Invention Explained

  • Problem Addressed: As a continuation of the '355 Patent, the '524 Patent addresses the same technical problem of managing stress and improving the durability and load capacity of caster wheels with elastomeric treads ʼ524 Patent, col. 2:19-53
  • The Patented Solution: The patent discloses the same core technology centered on a specifically shaped parabolic interface between the wheel hub and tread ʼ524 Patent, abstract The claims are structured differently but protect the same fundamental concept of using a parabolic geometry defined by the equation "y=A*x²" to redistribute load stresses within the tread from shear to compression ʼ524 Patent, col. 11:11-15
  • Technical Importance: The '524 patent broadens the protection for the innovative tread-hub interface, reinforcing the patentee's rights to the design that aims to overcome longstanding trade-offs in caster performance ʼ524 Patent, col. 2:54-63

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 7 Compl. ¶17
  • Essential Elements of Claim 7:
    • A hub with an outer rim section and an inner bearing section.
    • The rim section has an "annularly dished concave region" between a pair of cylindrical lips.
    • A tread with a conforming convex inner periphery and cylindrical pads in "direct surface-to-surface contact" with the hub's lips.
    • The "annularly dished concave region" has a "parabolic OD cross-section" defined by the equation "y=A*x², where A is between 1.5 and 4."
    • The bearing section includes an "inner bearing seat defined by a counter-bore."

III. The Accused Instrumentality

Product Identification

The accused products are Defendants' casters that include "Orbital wheels" Compl. ¶16

Functionality and Market Context

The complaint alleges that Defendants Schioppa (a Brazilian manufacturer) and DoRodo (its North American distributor) import, offer for sale, and sell the accused casters in the United States Compl. ¶¶18-19 The complaint asserts that these casters have the "parabolic profile" claimed in the Asserted Patents Compl. ¶16 The complaint also notes that the accused Orbital wheel is competitive with Plaintiff's own TWERGO products, which embody the patented technology Compl. ¶14 Compl. ¶34 The complaint includes a visual comparison between a patent figure and a cross-section of the accused Schioppa Orbital wheel, highlighting the alleged similarity in their profiles Compl. ¶16, p. 6

IV. Analysis of Infringement Allegations

The complaint provides detailed claim chart exhibits (Exhibits G and H) to support its infringement allegations.

'355 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a hub...said hub having an outer peripheral rim section and an inner bearing section... The accused Schioppa Orbital wheel includes a hub with an outer peripheral rim section and an inner bearing section. ¶17; Ex. G, p. 2 col. 4:46-54
a tread surrounding said rim surface, said tread fabricated from a resilient elastomeric material... The accused wheel has a resilient elastomeric tread surrounding the rim surface. ¶17; Ex. G, p. 5 col. 7:7-11
said tread having a convex inner periphery conforming to said annularly dished concave region of said rim surface in a nested relationship... The tread of the accused wheel has a convex inner periphery that conforms to the concave region of the hub's rim surface. ¶17; Ex. G, p. 5 col. 7:19-22
said cylindrical pads disposed in direct surface-to-surface contact with said cylindrical lips of said rim surface... The tread of the accused wheel includes cylindrical pads on each side of the convex inner periphery that are in direct contact with the cylindrical lips of the rim surface. ¶17; Ex. G, p. 5 col. 7:23-28
and wherein said annularly dished concave region...has a parabolic OD cross-section, wherein said parabolic OD cross-section is defined by the equation y=A*x², where A is between 1.5 and 4. The complaint provides a design drawing of the accused wheel, alleging its annularly dished concave region has a parabolic cross-section defined by the specified equation, even if it is a "compound profile." ¶17; Ex. G, p. 6 col. 5:31-44

'524 Patent Infringement Allegations

Claim Element (from Independent Claim 7) Alleged Infringing Functionality Complaint Citation Patent Citation
a hub comprising a generally annular body...having an outer peripheral rim section and an inner bearing section... The accused Schioppa Orbital wheel contains a hub with an annular body, an outer peripheral rim section, and an inner bearing section. ¶17; Ex. H, p. 2 col. 10:50-52
said rim section including an annular outer rim surface having an annularly dished concave region disposed between a pair of cylindrical lips... The accused hub's rim section has an annularly dished concave region between cylindrical lips. ¶17; Ex. H, p. 2 col. 10:54-57
a tread surrounding said rim surface...said tread having a convex inner periphery conforming to said annularly dished concave region...in a tight nested relationship... The accused wheel has a tread with a convex inner periphery that conforms to the hub's concave region in a nested relationship. ¶17; Ex. H, p. 3 col. 11:1-6
wherein said annularly dished concave region...has a parabolic OD cross-section...defined by the equation y=A*x², where A is between 1.5 and 4... The complaint alleges, with a supporting design drawing, that the accused wheel's concave region has a parabolic cross-section that meets the claimed mathematical definition. ¶17; Ex. H, p. 4 col. 11:11-15
and wherein said bearing section includes an inner bearing seat defined by a counter-bore. The bearing section of the accused hub includes an inner bearing seat defined by a counter-bore. ¶17; Ex. H, p. 5 col. 11:16-18
  • Identified Points of Contention:
    • Scope Questions: A principal question raised by the complaint's own evidence is whether the accused product's "compound profile made up of multiple regions represented by different radii" can satisfy the claim limitation requiring a "parabolic OD cross-section... defined by the equation y=A*x²" Compl. Ex. G, p. 6 Compl. Ex. H, p. 4 The resolution may depend on whether the claim requires a pure, continuous parabola or if a shape that approximates a parabola "taken as a whole" falls within the claim's scope.
    • Technical Questions: The complaint's allegation rests on the assertion that the accused product's geometry fits the claimed mathematical formula. A key evidentiary question will be what proof, such as expert measurement and curve-fitting analysis, demonstrates that the accused product's compound curve profile actually satisfies the equation "y=A*x²" with the constant 'A' falling within the claimed range of 1.5 to 4.

V. Key Claim Terms for Construction

  • The Term: "parabolic OD cross-section...defined by the equation y=A*x²"
  • Context and Importance: This term is the technological core of the asserted claims and the lynchpin of the infringement allegation. Its construction will likely determine whether the accused product's geometry, which the complaint itself characterizes as a "compound profile," can be found to infringe.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: Plaintiff may argue that the specification's focus on the function of the parabolic shape-to reorient stresses and improve durability-suggests the term should not be limited to a geometrically perfect parabola ʼ355 Patent, col. 3:16-29 Language describing the equation as producing a "suitable curve" could be cited to support a construction that includes shapes that are substantially or functionally parabolic ʼ355 Patent, col. 5:37-39
    • Evidence for a Narrower Interpretation: Defendants may argue that the claim's explicit recitation of a precise mathematical formula ("defined by the equation y=A*x²") limits the claim to only those shapes that strictly adhere to that formula. The specification's disclosure of a highly specific preferred value for the constant 'A' (3.5556) could be used to argue that the inventors contemplated a precise, not merely approximate, geometric shape ʼ355 Patent, col. 5:49-51

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement. It asserts inducement by alleging Defendants, with knowledge of the patents since at least March 2026, instruct and encourage customers to use the Orbital wheels in an infringing caster assembly Compl. ¶¶32-33 It asserts contributory infringement by alleging the Orbital wheels are a material part of the invention and have no substantial non-infringing uses as marketed by Defendants Compl. ¶¶35-37
  • Willful Infringement: Willfulness is alleged based on Defendants' continued infringement after receiving notice of the patents and the specific infringement allegations on March 5, 2026, several weeks before the complaint was filed Compl. ¶27 Compl. ¶39

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

The dispute as framed by the complaint appears to center on highly technical questions of geometry and claim scope. The case will likely turn on the answers to two central questions:

  • A core issue will be one of claim construction: does the limitation "parabolic OD cross-section... defined by the equation y=A*x²" require a pure, continuous mathematical parabola across the entire region, or can it be construed to cover a "compound profile" composed of multiple different radii that, when "taken as a whole," approximates the claimed equation?
  • A second key question will be factual and evidentiary: assuming a construction that could allow for non-perfect parabolas, can the Plaintiff prove through technical evidence and expert testimony that the specific geometry of the accused Orbital wheel actually satisfies the mathematical constraints of the claimed equation, including that the constant 'A' falls within the specified 1.5 to 4 range?
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