Why Milwaukee Tool Sued Klein Over A Patent Infringement

Are Milwaukee Tool and Klein Tools entering into a full-blown rivalry? With multiple lawsuits now on the record between two of the tool industry's biggest names, it certainly seems like it. Most recently, Milwaukee Tool has filed a lawsuit accusing Klein Tools of patent infringement over its tape measure technology. The complaint, which was filed on April 29, 2025, in the U.S. District Court for the Northern District of Illinois, alleges that several Klein tape measures unlawfully replicate Milwaukee's patent-protected features.

The patent in question was granted in May 2023. It covers a specific "tape blade profile increasing tape standout," which allows Milwaukee's tape measures to stretch farther without bending. Milwaukee's owners claim is that Klein's 25-foot tape measures (models 9225, 9125AL, and 9125) fall within the dimensions and mechanical ratios that are defined in its patent. Milwaukee's argument is that, directly or indirectly, the point remains: Klein's products infringe upon its invention.

According to the legal filing, Milwaukee has an issue with the specific measurements of Klein Tools' tape measure: a flat blade width between 29 and 32 millimeters, a curved height near 9 millimeters, and a standout distance over 150 inches. Milwaukee's lawsuit argues these measurements are patented under its formula and that Klein's use of them violates Milwaukee's intellectual property rights.

Milwaukee hopes the court will grant a permanent injunction that prevents Klein from manufacturing or selling the tape measures. Milwaukee is also hoping to receive financial damages to cover lost profits. If the court finds Klein's infringement "willful" (as Milwaukee hopes they will), federal patent law suggests it could lead to triple damages being paid out.

This tape measure issue is not the first time Milwaukee Tool has taken action against Klein Tools. In fact, the two companies entered into another legal dispute back in 2024: one that goes after Klein's MODbox line. It centers on three separate patents related to Milwaukee's coupling mechanisms, sliding paths, and interlocking features that allow Milwaukee's PACKOUT line to securely stack and connect.

Like the tape measure lawsuit, Milwaukee's case against Klein's modular storage system accuses them of "willful infringement." To qualify, Milwaukee would have to prove that Klein was aware of the protected patents and continued production regardless. If the courts rule in Milwaukee's favor, Klein could face some very serious repercussions. For one, the possible removal of MODbox systems and the tape measures from the market. That's not to mention the major financial penalties that would bring as well.

The twin lawsuits just go to show how aggressive Milwaukee's stance is toward its intellectual property. And can you blame them? It's how they're protecting the time and money invested into research, development, manufacturing, and distribution of their products. Plus, if a company fails to enforce its patent rights, it can lead to weakened protections in any and all future disputes. For now, though, both Milwaukee Tool and Klein Tools continue to stand their ground. Milwaukee has the right to protect its innovations, while Klein ownership has the right to compete.