DCT
1:25-cv-04689
Milwaukee Electric Tool Corp v. Klein Tools Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Milwaukee Electric Tool Corporation (Delaware)
- Defendant: Klein Tools, Inc. (Delaware)
- Plaintiff’s Counsel: Morgan, Lewis & Bockius LLP
- Case Identification: 1:25-cv-04689, N.D. Ill., 04/29/2025
- Venue Allegations: Venue is alleged to be proper in the Northern District of Illinois because the defendant, Klein Tools, maintains its corporate headquarters and principal place of business within the district and because the alleged acts of infringement are committed in the district.
- Core Dispute: Plaintiff alleges that Defendant’s line of tape measures infringes a patent related to a specific tape blade profile engineered to increase the unsupported extension distance, or "standout."
- Technical Context: The technology concerns the mechanical design of retractable tape measures, a mature product category where performance characteristics like blade stiffness and standout are key competitive differentiators in the professional trades market.
- Key Procedural History: The patent-in-suit is part of a larger family of applications and patents, tracing its priority back to 2017. The complaint does not mention any prior litigation between the parties or challenges to the patent family at the U.S. Patent and Trademark Office.
Case Timeline
| Date | Event |
|---|---|
| 2017-08-24 | U.S. Provisional Application Priority Date for '067 Patent |
| 2023-05-23 | U.S. Patent No. 11,656,067 Issues |
| 2025-04-29 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 11,656,067 - "Tape Measure with Tape Blade Profile Increasing Tape Standout," issued May 23, 2023
The Invention Explained
- Problem Addressed: The patent addresses the technical challenge of increasing a tape measure blade's "standout"—the distance it can extend horizontally without buckling under its own weight—which is a critical feature for professional users. The background suggests a need to achieve this increased performance, potentially even with thinner or narrower steel blades, without creating other problems like poor readability of measurement markings due to excessive curvature. ('067 Patent, col. 4:35-54).
- The Patented Solution: The invention claims a specific, engineered cross-sectional profile for the metal tape blade. Rather than simply curving the blade, the patent claims a precise combination of physical dimensions, including the metal core thickness, flat width, curved width, and curved height, as well as specific mathematical ratios between these dimensions. ('067 Patent, Abstract; col. 8:30-38). This quantified geometric profile is asserted to increase the blade's rigidity and resistance to buckling, thereby achieving superior standout distances. ('067 Patent, col. 4:45-47).
- Technical Importance: This approach suggests a method for optimizing a key performance metric (standout) through precise geometric control, potentially allowing for the creation of more compact and lightweight tape measures that still meet professional performance demands. ('067 Patent, col. 4:38-42).
Key Claims at a Glance
- The complaint asserts independent Claim 1. (Compl. ¶20).
- The essential elements of Claim 1 include:
- A standard tape measure assembly with a housing, reel, and retraction system.
- An elongate blade comprising an elongate metal core with a specific thickness (0.12 mm to 0.14 mm) and length (15 to 40 feet).
- A specific "flat width" of the blade (20 mm to 40 mm).
- A specific "curved height" of the blade's cross-section (8.5 mm to 9.5 mm).
- A required ratio of curved width to flat width (between 0.6 and 0.8).
- A required ratio of curved height to flat width (greater than 0.285).
- A resulting "standout distance" from the housing that is "greater than 150 inches."
- The complaint alleges infringement of "one or more claims" and identifies Claim 1 as "Representative," reserving the right to assert other claims. (Compl. ¶20).
III. The Accused Instrumentality
Product Identification
- The complaint identifies the Klein Tools Tape Measure models 9225 (25-Foot Magnetic Double-Hook), 9125AL (25-Foot Single-Hook Auto-Lock), and 9125 (25-Foot Single-Hook) as "the Accused Products." (Compl. ¶16).
Functionality and Market Context
- The Accused Products are retractable tape measures marketed to professional users. (Compl. ¶21). The complaint alleges that these products possess the specific physical dimensions and performance characteristics recited in the '067 Patent. (Compl. ¶27). A promotional image from Klein Tools' marketing materials is included in the complaint, advertising a "13' STANDOUT" (156 inches) for its tape measures. (Compl. p. 7). The complaint also presents a table containing specific, precise measurements of the Accused Products' blade geometry and performance, alleging they fall within the claimed ranges. (Compl. ¶27).
IV. Analysis of Infringement Allegations
'067 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a housing; a tape reel rotatably mounted within the housing; | Each Accused Product has a housing and a tape reel rotatably mounted within it. | ¶26 | col. 5:21-22 |
| an elongate blade wound around the reel...a curved profile such that the upper surface...defines a concave surface and the lower surface defines a convex surface | Each Accused Product has an elongate blade with a curved profile where the upper surface is concave and the lower surface is convex. | ¶26 | col. 5:22-29 |
| an elongate metal core having a first thickness, T1, between 0.12 mm and 0.14 mm; | Each Accused Product allegedly has a metal core thickness of 0.13 mm. | ¶27 | col. 5:30-32 |
| a length between 15 feet and 40 feet; | Each Accused Product allegedly has a blade length of 26 ft. | ¶27 | col. 8:48-49 |
| a flat width of 20 mm to 40 mm; | Each Accused Product allegedly has a flat width of 32 mm. | ¶27 | col. 8:40-41 |
| a curved height between 8.5 mm and 9.5 mm; | Each Accused Product allegedly has a curved height between 9.1859 mm and 9.3356 mm. | ¶27 | col. 9:1-2 |
| wherein a ratio of the curved width to the flat width is between 0.6 and 0.8; | Each Accused Product allegedly has a CW/FW ratio between 0.723438 and 0.749463. | ¶27 | col. 8:61-63 |
| wherein a ratio of curved height to flat width is greater than 0.285; | Each Accused Product allegedly has a CH/FW ratio between 0.287059 and 0.291738. | ¶27 | col. 9:6-7 |
| wherein a standout distance of the elongate blade from the housing is greater than 150 inches; and | Each Accused Product allegedly has a standout between 156 and 171 inches. A marketing image advertises a "13' STANDOUT" (156 inches). (Compl. p. 7). | ¶27 | col. 2:25-27 |
| a retraction system coupled to the tape reel...drives rewinding of the elongate blade on to the tape reel. | Each Accused Product has a retraction system that rewinds the blade. | ¶26 | col. 5:41-45 |
Identified Points of Contention
- Technical Questions: The complaint's allegations hinge on a set of highly specific measurements for the Accused Products, provided with up to six decimal places. (Compl. ¶27). A central point of contention will be factual and evidentiary: does expert testing and measurement of the Accused Products confirm that they meet every numerical limitation recited in Claim 1? The precision of the allegations suggests Plaintiff has conducted its own testing, which will likely be countered by Defendant's own expert analysis, focusing on measurement techniques and potential variability.
- Scope Questions: The term "standout distance" is defined in the patent's specification by a particular test methodology. ('067 Patent, col. 7:55 - col. 8:10). The dispute may therefore raise the question of whether the Accused Products meet the "greater than 150 inches" threshold when measured according to the specific protocol outlined in the patent.
V. Key Claim Terms for Construction
- The Term: "standout distance"
- Context and Importance: This term is a critical performance-based limitation. Infringement of this element is not merely a matter of observation but requires a specific test. Practitioners may focus on this term because its definition is tied to a specific measurement protocol described in the patent specification, making the method of testing as important as the result itself.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue that "standout" has a plain and ordinary meaning in the art of tape measures. However, the specification's explicit reference to a test protocol may limit the viability of such an argument.
- Evidence for a Narrower Interpretation: The '067 Patent specification states that "tape standout distance, as used herein, is determined via preceding test procedure." ('067 Patent, col. 8:56-60). It then describes a "droop measurement test," including how the tape blade is to be supported by the housing's guard assembly during the test. ('067 Patent, col. 8:1-10). This language provides strong evidence that the term was intended to be defined by the specific test procedure described, giving it a precise, limited meaning.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement, asserting that Klein Tools provides instructions and advertisements encouraging customers to use the Accused Products in an infringing manner. (Compl. ¶30). The complaint further alleges that Defendant's website, which includes a "BUY NOW" option linking to online retailers, facilitates these infringing sales. (Compl. ¶31).
- Willful Infringement: Willfulness is alleged based on Klein Tools' knowledge of the '067 Patent "at least as of the date of the filing and service of this Complaint." (Compl. ¶¶ 13, 32, 35). The pleading does not assert pre-suit knowledge, grounding the willfulness claim in alleged post-filing conduct.
VII. Analyst’s Conclusion: Key Questions for the Case
The dispute centers on highly quantitative and test-based claim limitations, suggesting the case will turn on factual evidence more than on legal interpretation of claim scope.
- A primary issue will be one of evidentiary verification: Will discovery and expert testing confirm that the accused Klein Tools products possess the exact dimensional properties and mathematical ratios—such as metal core thickness, curved height, and the ratio of curved height to flat width—as required by every limitation of Claim 1?
- A second core question will be one of definitional testing: When subjected to the specific "droop measurement test" protocol detailed in the '067 patent's specification, do the accused products in fact achieve a "standout distance" greater than 150 inches? The case may depend on a "battle of the experts" over the correct application of this patented test method.