KAI USA Ltd v. Wuu Jau Co Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: KAI U.S.A., LTD. d/b/a/ KERSHAW KNIVES (Oregon)
  • Defendant: Wuu Jau Co., Inc. (Oklahoma) and Neptune Trading Inc. (California)
  • Plaintiff’s Counsel: STOLL STOLL BERNE LOKTING & SHLACHTER P.C.; SEED IP LAW GROUP, PLLC
• Case Identification: 3:15-cv-02108, D. Ore., 11/10/2015
• Venue Allegations: Venue is alleged to be proper because Defendants offer for sale and sell the accused products within the district, and Plaintiff’s principal place of business and manufacturing facilities are located in the district.
• Core Dispute: Plaintiff alleges that Defendants’ line of "Spring Assisted Pocket Knives" infringes four U.S. patents related to assisted-opening mechanisms, blade-mounted locks, and safety features for folding knives.
• Technical Context: The technology at issue involves mechanisms that use a spring or other biasing element to help a user open a folding knife with one hand, a popular feature in the consumer and professional cutlery market.
• Key Procedural History: The complaint alleges that Plaintiff provided Defendant Wuu Jau Co., Inc. with notice of the alleged infringement on or about October 1, 2015, approximately six weeks before filing the lawsuit.

Case Timeline

Date	Event
1998-03-10	Priority Date for U.S. Patent No. 6,145,202 and 6,397,476
1999-04-19	Priority Date for U.S. Patent No. 6,338,431 and 7,340,838
2000-11-14	U.S. Patent No. 6,145,202 Issued
2002-01-15	U.S. Patent No. 6,338,431 Issued
2002-06-04	U.S. Patent No. 6,397,476 Issued
2008-03-11	U.S. Patent No. 7,340,838 Issued
2015-10-01	Plaintiff allegedly informed Defendant Wuu Jau of infringement
2015-11-10	Complaint Filed

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

U.S. Patent No. 6,145,202 - “Opening and Closing Assisting Mechanism for Folding Knife” (Issued Nov. 14, 2000)

The Invention Explained

• Problem Addressed: The patent seeks to overcome deficiencies in conventional folding knives by providing a mechanism that assists in both opening and closing the blade, enabling the action to be performed with a single hand, which is particularly beneficial for users who may have difficulty using two hands for physical or safety reasons (’202 Patent, col. 1:23-31).
• The Patented Solution: The invention employs a "bias element," such as a torsion bar, housed within a recessed portion of the handle and offset from the blade's path. This element engages the blade's tang. A user must manually rotate the blade past an "equilibrium point," after which the stored energy in the bias element automatically drives the blade to the fully open position without further user force (’202 Patent, Abstract; col. 3:13-24). The mechanism is illustrated in Figure 4, showing the bias element (29) interacting with the blade tang (28).
• Technical Importance: This design provided a method for creating a reliable and easy-to-use "assisted-opening" or "semi-automatic" folding knife.

Key Claims at a Glance

• The complaint does not identify specific asserted claims (Compl. ¶15). Independent claim 1 is representative of the core invention.
• Independent Claim 1 Recites:
  • a blade having a tang extending outwardly from the blade;
  • a handle having at least one recessed portion;
  • a bar pivotally connecting the tang and the handle; and
  • a bias element engaging the blade, housed within the recessed portion of the handle, such that the bias element is "substantially to one side of a plane defined by said blade" and assists the blade’s movement to an open position.
• The complaint's general allegations may be read to reserve the right to assert any claims from the patent, including dependent claims.

U.S. Patent No. 6,338,431 - “Locking Knife Blade with Moving Locking Mechanism on Blade” (Issued Jan. 15, 2002)

The Invention Explained

• Problem Addressed: The patent describes a need for a locking mechanism that secures a folding knife blade in the open position but also facilitates simple, one-handed unlocking and closing of the blade (’431 Patent, col. 1:12-18).
• The Patented Solution: The invention centers on a locking "post" that is mounted within a slot on the blade itself, allowing it to slide relative to the blade. When the blade is opened, a spring can urge the post into a locking position where it abuts a surface on the handle, preventing closure. To close the knife, the user manually retracts the post on the blade, disengaging it from the handle and allowing the blade to pivot shut (’431 Patent, Abstract; col. 3:1-11). Figure 1 depicts the post (30) on the blade (12) and its interaction with the handle (16).
• Technical Importance: By placing the movable locking and unlocking mechanism directly on the blade, the design enables a user to control the lock with the same hand holding the knife, potentially simplifying one-handed operation compared to traditional handle-based locks.

Key Claims at a Glance

• The complaint does not identify specific asserted claims (Compl. ¶15). Independent claim 2 is representative of the locking mechanism.
• Independent Claim 2 Recites:
  • a blade with a tang and a handle to which the tang is pivotally connected, defining a plane of travel for the blade; and
  • a "post extending transversely outward from the plane of travel of the blade and slidably held by the blade" to move between a retracted and a locking position;
  • wherein in the locking position, the handle and the post block the blade from pivoting toward the closed position.
• The complaint's general allegations may be read to reserve the right to assert any claims from the patent, including dependent claims.

Multi-Patent Capsule: U.S. Patent No. 6,397,476

• Patent Identification: U.S. Patent No. 6,397,476, “Opening and Closing Assisting Mechanism for a Folding Knife,” Issued June 4, 2002 (Compl. ¶12).
• Technology Synopsis: As a continuation of the '202 patent, this patent further details a spring-assisted opening mechanism. The invention describes a bias element that operates on the blade through a cavity formed in the handle, where the cavity is specifically described as extending parallel to and spaced outwardly from the blade's plane of travel and is at least partially enclosed by a handle lining (’476 Patent, Abstract; Claim 1).
• Asserted Claims: The complaint asserts infringement of "one or more claims" without further specification (Compl. ¶15).
• Accused Features: The complaint alleges that the general "assisted opening" functionality of Defendants' "Spring Assisted Pocket Knives" infringes the patent (Compl. ¶15).

Multi-Patent Capsule: U.S. Patent No. 7,340,838

• Patent Identification: U.S. Patent No. 7,340,838, “Folding Knife with Safety Lock,” Issued Mar. 11, 2008 (Compl. ¶13).
• Technology Synopsis: This patent discloses a safety lock designed to prevent a folding knife, particularly one with an assisted-opening feature, from opening unintentionally. The invention consists of a lock that is movably mounted on the handle and can be slid into a "locked position" to physically obstruct the blade's path of travel, preventing it from pivoting out of the handle (’838 Patent, Abstract; col. 1:35-46).
• Asserted Claims: The complaint asserts infringement of "one or more claims" without further specification (Compl. ¶15).
• Accused Features: The complaint's allegations suggest that safety lock features on the Defendants' accused knives are the infringing instrumentalities (Compl. ¶15).

III. The Accused Instrumentality

• Product Identification: The accused instrumentalities are "various models of assisted opening knives" sold by Defendants, which are referred to on Defendants' websites as "Spring Assisted Pocket Knives" (Compl. ¶15). Specific brands listed include Buckshot, Tac-Force, Wartech, MILSPEC, OG Knives, BIOHAZARD, America's NAVY, US ARMY, FAMOUS, and Super Bitch, with several model numbers also identified (Compl. ¶16).
• Functionality and Market Context: The complaint alleges that the Accused Products possess "the same claimed features as those included in the patented Kai USA products for their Speed Safe® knives," implying they incorporate spring-assisted opening mechanisms (Compl. ¶15). The assertion of the full patent family suggests these knives may also include specific blade-locking and safety-locking features. The products are allegedly marketed and sold nationwide through Defendants' websites and showrooms (Compl. ¶6).

IV. Analysis of Infringement Allegations

The complaint does not provide element-by-element infringement allegations or include claim charts. The infringement theory is articulated at a high level, stating that all spring-assisted knives sold by Defendants infringe one or more claims of the four patents-in-suit (Compl. ¶17). The core allegation is that the Defendants' "Spring Assisted Pocket Knives" (Compl. ¶15) incorporate the patented technologies for assisted opening (’202 and ’476 Patents), blade-mounted locks (’431 Patent), and safety locks (’838 Patent). No probative visual evidence provided in complaint.

• Identified Points of Contention:
  • ’202 Patent: The infringement analysis may focus on the structural arrangement of the opening mechanism. A key question is whether the accused knives employ a bias element that is "housed within said recessed portion of said handle such that said bias element is substantially to one side of a plane defined by said blade" (Claim 1). The spatial relationship between the spring and the blade plane appears to be a critical limitation that may be a point of dispute.
  • ’431 Patent: For the ’431 patent, the central dispute is likely to be whether the accused products use a lock that is "slidably held by the blade" (Claim 2). A technical question for the court will be whether the accused knives embody this specific blade-mounted, sliding-post lock, or if they instead use a more conventional lock integrated into the handle (e.g., a liner lock), which could create a technical mismatch with the claim language.

V. Key Claim Terms for Construction

• ’202 Patent (Claim 1): "substantially to one side of a plane defined by said blade"

  • Context and Importance: This phrase defines the spatial location of the bias element relative to the blade. Its construction is critical because it distinguishes the claimed invention from mechanisms where a spring might operate within the same plane as the blade. Practitioners may focus on this term to determine if the accused products' spring placement falls within the scope of the claim.
  • Intrinsic Evidence for a Broader Interpretation: The use of the word "substantially" suggests the patentee did not intend to limit the claim to an exact, perfectly offset position, allowing for some degree of variation. The patent also describes alternate embodiments, such as a coiled wire, which may imply flexibility in the precise arrangement (’202 Patent, col. 4:1-13).
  • Intrinsic Evidence for a Narrower Interpretation: The preferred embodiment clearly shows the bias element (29) housed in a recess (24) on one side piece of the handle, distinctly separate from the central channel (19) where the blade rests (’202 Patent, Fig. 3-4; col. 2:49-54). This could support an argument that "substantially to one side" requires a clear structural offset into a handle side-piece.

• ’431 Patent (Claim 2): "post ... slidably held by the blade"

  • Context and Importance: This term defines the core of the locking invention: a lock that is part of and moves with the blade. Infringement of this patent family likely hinges on whether the accused products contain such a feature. The definition of "post" and what it means to be "slidably held by the blade" will be central.
  • Intrinsic Evidence for a Broader Interpretation: The term "post" is not explicitly defined and could be argued to cover any member that projects to create a block. "Slidably held" could encompass any mechanism permitting linear movement, not just a pin in a slot.
  • Intrinsic Evidence for a Narrower Interpretation: The specification and figures consistently depict the "post" (30) as a discrete, pin-like component that moves within a defined, linear "slot" (60) machined through the blade (’431 Patent, Fig. 6; col. 3:1-4). This could support a narrower construction requiring a distinct pin-in-slot structure, as opposed to other types of latches that might be integrated with the blade.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement. It asserts that Defendants actively induce their customers to infringe by selling the Accused Products, and that the products are specifically manufactured for infringement and have no substantially non-infringing uses (Compl. ¶¶ 26, 25 [second paragraph 25], 26 [second paragraph 26]).
• Willful Infringement: The complaint alleges that Defendants' infringement has been willful, at least since receiving Plaintiff's notice letter dated October 1, 2015 (Compl. ¶¶ 22-23, 29). This allegation is based on alleged actual notice of the patents-in-suit.

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

1. Evidentiary Proof: Given the complaint’s lack of specific, element-by-element infringement allegations, a threshold issue will be an evidentiary one: can the plaintiff, through discovery, produce evidence demonstrating that the various accused knife models actually practice the specific mechanical structures required by the asserted patent claims?
2. Technical Scope: The case will likely turn on questions of technical scope and potential mismatch. For the assisted-opening patents (’202/’476), does the accused mechanism's spring operate "substantially to one side" of the blade's plane as claimed? For the locking patent (’431), does the accused lock constitute a "post... slidably held by the blade," or does it utilize a conventional handle-based lock, placing it outside the claim's literal scope?
3. Combination of Features: A further question is one of infringement overlap: how many of the accused knife models practice the combination of patented features? Resolution may require determining which products, if any, infringe the assisted-opening claims, the blade-mounted lock claims, and the safety-lock claims, as opposed to only one of these technologies.