Baker v. Billdon LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Scott Baker (California)
  • Defendant: Billdon LLC (dba BILLY Footwear) (Washington)
  • Plaintiff's Counsel: Law Office of Scott Baker
• Case Identification: 2:26-cv-02320, C.D. Cal., 02/17/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Central District of California because Defendant conducts continuous business in the district through online sales and retail partners, including Target and Kohl's, which Plaintiff characterizes as strategic partnerships establishing a "regular and established place of business" for Defendant in California.
• Core Dispute: Plaintiff alleges that Defendant's footwear products infringe six U.S. patents related to adaptive shoe designs featuring a wrap-around zipper that allows the shoe's upper portion to open for easy foot access.
• Technical Context: The technology resides in the field of adaptive footwear, designed to assist individuals with limited mobility or other disabilities in wearing conventional-style shoes.
• Key Procedural History: The complaint alleges that Plaintiff sent Defendant a series of six separate cease and desist letters. Each letter was allegedly sent shortly after the issuance of each of the six patents-in-suit, beginning in January 2019, forming the basis for the willfulness allegations.

Case Timeline

Date	Event
2013-06-14	Earliest Priority Date for all Patents-in-Suit ('893, '796, '733, '630, '806, '089)
2019-01-15	'893 Patent Issued
2019-01-25	Cease and Desist Letter for '893 Patent Allegedly Sent
2020-10-06	'796 Patent Issued
2020-10-16	Cease and Desist Letter for '796 Patent Allegedly Sent
2021-11-16	'733 Patent Issued
2021-11-19	Cease and Desist Letter for '733 Patent Allegedly Sent
2023-09-12	'630 Patent Issued
2023-09-18	Cease and Desist Letter for '630 Patent Allegedly Sent
2023-12-26	'806 Patent Issued
2024-05-28	'089 Patent Issued
2024-07-15	Cease and Desist Letter for '089 Patent Allegedly Sent
2024-08-27	Cease and Desist Letter for '806 Patent Allegedly Sent
2026-02-17	First Amended Complaint Filed

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

U.S. Patent No. 10,178,893 - "SHOE"

(Issued January 15, 2019; '893 Patent)

The Invention Explained

• Problem Addressed: The patent describes the difficulty individuals with limited muscular control or paralysis face when putting on conventional shoes, where toes can bend or curl, potentially causing circulatory problems, swelling, and discomfort ʼ893 Patent, col. 1:53-2:14
• The Patented Solution: The invention is a shoe with a unique zipper path that allows a significant portion of the shoe's upper to open and fold away from the sole ʼ893 Patent, abstract This creates a wide, unobstructed opening, enabling a user to place their foot directly onto the sole without needing to slide it through a narrow ankle opening, thereby keeping the toes in a natural, flat position (ʼ893 Patent, col. 2:27-41; ʼ893 Patent, FIG. 2).
• Technical Importance: This design allows for the creation of fashionable and conventional-looking shoes that are accessible to people with disabilities, who might otherwise be limited to orthopedic or less stylish adaptive footwear ʼ893 Patent, col. 4:50-65

Key Claims at a Glance

• The complaint asserts independent claim 1 (Compl. p. 35).
• Claim 1 of the '893 Patent generally recites:
  • A shoe with a sole and a top member defining a space for a foot.
  • A single continuous zipper fastener.
  • The zipper extends from a starting point at a midpoint of the ankle opening on the medial side.
  • The zipper traverses the medial side of the top member, continues across the distal front end portion, and then traverses the lateral side of the top member.
  • The zipper terminates at a point on the lateral side of the top member.
  • This configuration allows a "fold back portion" of the top member to be movable to provide foot access to the space.

U.S. Patent No. 10,791,796 - "SHOE"

(Issued October 6, 2020; '796 Patent)

The Invention Explained

• Problem Addressed: The patent addresses the same problem as the '893 Patent: the difficulty and potential for injury when individuals with limited mobility put on conventional shoes ʼ796 Patent, col. 1:54-2:14
• The Patented Solution: Like the '893 Patent, this invention discloses a shoe with a wrap-around zipper that allows the upper to open wide for easy foot placement ʼ796 Patent, abstract The primary distinction from the '893 Patent appears to be the specific path of the zipper as defined in the claims ʼ796 Patent, FIG. 1 ʼ796 Patent, col. 10:8-33
• Technical Importance: The invention provides an alternative configuration for an accessible, fashionable shoe, broadening the design options for adaptive footwear ʼ796 Patent, col. 4:55-65

Key Claims at a Glance

• The complaint asserts independent claim 1 (Compl. p. 40).
• Claim 1 of the '796 Patent generally recites:
  • A shoe with a sole and a top member defining a space for a foot.
  • A single continuous zipper fastener.
  • The zipper extends from a starting point at a midpoint of the ankle opening on the lateral side.
  • The zipper traverses the lateral side of the top member, continues across the distal front end portion, and then traverses the medial side of the top member.
  • The zipper terminates at a point on the medial side of the top member.
  • This configuration allows a "fold back portion" of the top member to be movable to provide foot access.

U.S. Patent No. 11,172,733 - "SHOE"

(Issued November 16, 2021; '733 Patent)

• Technology Synopsis: The '733 patent describes a similar zippered shoe technology for easy foot access, addressing the same problems for users with limited mobility ʼ733 Patent, col. 1:5-10 ʼ733 Patent, abstract The claims appear to focus on different specific zipper path configurations compared to the earlier patents.
• Asserted Claims: Independent Claim 1 (Compl. p. 44).
• Accused Features: The complaint alleges that the wrap-around zipper design of the Accused Products infringes the '733 patent Compl. ¶¶49-50

U.S. Patent No. 11,751,630 - "SHOE"

(Issued September 12, 2023; '630 Patent)

• Technology Synopsis: The '630 patent builds on the core zippered shoe concept but adds features related to the zipper's placement relative to the sole and the inclusion of a "flexible barrier" ʼ630 Patent, abstract The barrier is intended to prevent a wearer's sock or other material from getting caught in the zipper teeth during closure ʼ630 Patent, col. 9:38-42
• Asserted Claims: Independent Claim 1 (Compl. p. 48).
• Accused Features: The complaint alleges that the zipper functionality of the Accused Products, which allows the upper to open, infringes the '630 patent Compl. ¶¶55-56

U.S. Patent No. 11,849,806 - "SHOE"

(Issued December 26, 2023; '806 Patent)

• Technology Synopsis: The '806 patent describes a zippered shoe that further incorporates an "expandable vertical band" and a "securement cover flap" ʼ806 Patent, claim 2 This feature is designed to allow the shoe's ankle opening to expand to accommodate an ankle brace while maintaining a secure fit ʼ806 Patent, abstract
• Asserted Claims: Independent Claim 2 (Compl. p. 53).
• Accused Features: The complaint alleges that the wrap-around zipper and overall construction of the Accused Products infringe the '806 patent Compl. ¶¶61-62

U.S. Patent No. 11,992,089 - "SHOE WITH EXPANDABLE TOP"

(Issued May 28, 2024; '089 Patent)

• Technology Synopsis: The '089 patent describes a zippered shoe that also includes traditional laces and eyelets over a flap or tongue ʼ089 Patent, abstract This configuration allows the shoe to maintain the appearance of a standard lace-up shoe while still providing the accessibility of the wrap-around zipper ʼ089 Patent, claim 13
• Asserted Claims: Independent Claim 13 (Compl. p. 57).
• Accused Features: The complaint alleges that the Accused Products, particularly those with laces, utilize the patented combination of a zipper and expandable top Compl. ¶¶67-68

III. The Accused Instrumentality

Product Identification

The complaint accuses a wide range of Defendant's footwear sold under the "Billy Footwear" brand, including numerous sub-category labels such as "Billy Classic high," "Billy CS high," "Billy Short wrap low," and "Billy Lugs II" (Compl. ¶9; Compl. ¶10).

Functionality and Market Context

The Accused Products are alleged to be adaptive footwear that incorporates a zipper starting near the ankle opening, which then traverses the side of the shoe, wraps around the toe portion, and continues partially up the other side Compl. ¶9 This design allows the entire upper portion of the shoe to be flipped open as a "large flap," revealing the internal area for easy foot placement Compl. ¶9 The complaint provides an image of the accused "Billy Classic High" product, showing the shoe with its zippered top portion folded open Compl. ¶13 Another image shows the "Billy Lugs II" boot with its upper similarly opened, demonstrating the accused functionality in a different shoe style Compl. ¶16 The products are marketed and sold directly to consumers online and through major retail partners such as Nordstrom, Target, and Kohl's Compl. ¶4c Compl. ¶4d Compl. ¶11

IV. Analysis of Infringement Allegations

'893 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a sole (1) having an upper surface (1A), an outer edge (1B), and a lower surface (1C)	The accused product has a sole with an upper surface, an outer edge, and a lower surface, which are described as standard features for enclosed footwear.	¶35	col. 5:61-62
... a single fastening means in the form of one continuous zipper fastener (5) ...	The accused product has a single fastening means in the form of one continuous zipper fastener.	¶36	col. 6:2-4
extending from a starting point (5A) at a midpoint between the distal end (4A) and the proximal end (4B) of the ankle opening (4) on the medial side of the ankle opening (4C)	The accused product's zipper extends from a starting point at the ankle opening on the lateral side. The complaint alleges this is an insubstantial difference under the Doctrine of Equivalents.	¶36	col. 6:9-13
traversing the medial side of the top member (2D) ... towards the connection area ...	The accused product's zipper traverses the lateral side of the top member. The complaint alleges this "mirroring" is an insubstantial difference under the Doctrine of Equivalents.	¶36	col. 6:13-18
... continuing across the distal front end portion of the shoe (2A) at the connection area, to where the distal front end portion (2A) becomes the lateral side of the top member (2C)	The accused product's zipper continues across the distal front end and becomes the medial side. The complaint alleges this "mirroring" is an insubstantial difference under the Doctrine of Equivalents.	¶¶36-37	col. 6:18-22
... then traversing the lateral side of the connection area, the zipper fastener (5) travelling in a direction towards the proximal heel end portion of the shoe (2B),	The accused product's zipper then traverses the medial side. The complaint alleges this "mirroring" is an insubstantial difference under the Doctrine of Equivalents.	¶37	col. 6:22-26
a zipper termination point (5B) located midway between the distal front end portion of the shoe (2A) and the distal end of the ankle opening (4A) on the lateral side of the top member (2C)	The accused product's zipper terminates on the medial side. The complaint alleges this "mirroring" is an insubstantial difference under the Doctrine of Equivalents.	¶37	col. 6:26-30

'796 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a sole (1) having an upper surface (1A), an outer edge (1B), and a lower surface (1C)	The accused product has a sole with standard features for enclosed footwear.	¶40	col. 9:57-58
... a single fastening means in the form of one continuous zipper fastener (5) ...	The accused product has a single continuous zipper fastener.	¶41	col. 10:5-7
extending from a starting point (5A) at a midpoint between the distal end (4A) and the proximal end (4B) of the ankle opening (4) on the lateral side of the ankle opening (4C)	The accused product's zipper starts forward of the midpoint of the ankle opening on the lateral side. The complaint alleges this is an obvious variation and insubstantial difference under the Doctrine of Equivalents.	¶41	col. 10:8-13
traversing the lateral side of the top member (2D) at a descending angle ... towards the connection area ...	The accused product's zipper traverses the lateral side of the top member at a descending angle towards the connection area. The complaint alleges this is literal infringement.	¶41	col. 10:13-18

Identified Points of Contention

• Scope Questions: For the '893 Patent, the infringement analysis appears to depend entirely on the Doctrine of Equivalents. The complaint alleges the accused products have a zipper path that is a mirror image of the one claimed (i.e., lateral vs. medial) Compl. p. 36 This raises the question of whether "mirroring" the entire claimed path constitutes an insubstantial difference or if it impermissibly vitiates express claim limitations.
• Technical Questions: For the '796 Patent, a key dispute may arise over the term "midpoint." The complaint alleges the accused product's zipper starts "forward of the midpoint" and asserts infringement under the Doctrine of Equivalents for this element Compl. p. 41 The analysis will question what evidence exists to show this deviation is an "insubstantial difference" and how narrowly the term "midpoint" will be construed.

V. Key Claim Terms for Construction

Term: "medial side" vs. "lateral side"

(from '893 Patent, Claim 1)

• Context and Importance: The '893 Patent claims a zipper path starting on the "medial side," while the complaint alleges the accused product's zipper is on the "lateral side" and is thus an equivalent Compl. p. 36 The construction of these directional terms, and whether their interchangeability is an "insubstantial difference," is fundamental to the infringement allegation for this patent.
• Intrinsic Evidence for a Broader Interpretation: The specification's primary focus is on the functional result: allowing the top of the shoe "to open up and out of the way" for easy foot insertion ʼ893 Patent, col. 2:27-32 A party might argue that as long as this function is achieved, the specific side (medial or lateral) is not a critical aspect of the invention.
• Intrinsic Evidence for a Narrower Interpretation: Claim 1 explicitly and repeatedly distinguishes between the "medial side" and the "lateral side" to define a specific zipper path ʼ893 Patent, col. 10:1-33 The patent drawings, such as FIG. 1, consistently depict the claimed medial-to-lateral path. A party may argue this specificity was intentional and essential to define the invention over the prior art.

Term: "at a midpoint"

(from '796 Patent, Claim 1)

• Context and Importance: The complaint alleges the accused product's zipper starts "forward of the midpoint" of the ankle opening, relying on the Doctrine of Equivalents for this element Compl. p. 41 The definition of "midpoint"-whether it is a precise geometric point or a general region-will be critical to determining literal infringement and framing the equivalents analysis.
• Intrinsic Evidence for a Broader Interpretation: Practitioners may focus on the overall function of providing an access point. The specification states the zipper can be "conveniently located on any part of the shoe" to achieve the invention's objective ʼ796 Patent, col. 6:46-51, which may support an argument that the exact starting point is not a strict limitation.
• Intrinsic Evidence for a Narrower Interpretation: The term "midpoint" has a plain and ordinary meaning that suggests a specific central location. The claim language is precise in locating the starting point "at a midpoint between the distal end and the proximal end" of the opening ʼ796 Patent, col. 10:8-10, which could support a narrow construction limited to that specific location.

VI. Other Allegations

Indirect Infringement

The complaint does not contain a separate count for indirect infringement. However, the prayer for relief seeks to enjoin Defendant and its "retailers, wholesalers, and all other persons acting in concert" from acts including "supplying, distributing, offering for sale, or selling" the Accused Products Compl. ¶92 The factual basis for inducement may be inferred from allegations of Defendant's marketing and distribution partnerships Compl. ¶¶3-4 Compl. ¶11

Willful Infringement

The complaint alleges willful infringement for all six patents-in-suit, dedicating a separate claim to each Compl. ¶¶72-89 The basis for willfulness is alleged pre-suit knowledge derived from a series of six cease and desist letters Plaintiff claims to have sent to Defendant, with each letter corresponding to a newly issued patent and sent shortly after its issuance date Compl. ¶74 Compl. ¶77 Compl. ¶80 Compl. ¶83 Compl. ¶86 Compl. ¶89

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

• A central issue will be one of equivalency and claim scope: For the '893 patent, the case may turn on whether "mirroring" the entire claimed zipper path from the medial to the lateral side is an insubstantial difference under the Doctrine of Equivalents, or if it vitiates an express claim limitation. The outcome will depend on how essential the specific claimed path is to the invention as a whole.
• A second key question will be one of definitional precision: The construction of the term "midpoint" in the '796 patent will be critical. The court will need to decide if the term denotes a precise geometric location, which would limit the claim's literal scope, or a more general region, which could broaden it.
• A third major question will be one of culpability and damages: Given the allegation that Defendant received six separate cease and desist letters over a multi-year period as the patent portfolio grew, a key evidentiary focus will be on whether Defendant's continued alleged infringement constitutes objective recklessness, which would support a finding of willfulness and potential for enhanced damages.