[This story was revised on 11/6/2014. No information was deleted, but comments were added by the author.]

A recent story by Courthouse News Service described a series of patent infringement lawsuits filed by Milwaukee Electric Tool Corp and associated companies (TTi, Metco Battery Technologies, and others) against “power tool heavy-hitters like Snap-On Inc. and Hilti Inc. for using multi-cell lithium ion batteries in their products.” Hilti and Snap-On are significant companies, but not the first that come to mind when one thinks of major players in the cordless power tool category. Wanting to know more, I tracked down the court filings and found out which companies Milwaukee is suing.

Patent infringement suits were filed on 10/16/14 in Wisconsin Eastern District Court against:

  • Hilti Inc.
  • Max USA Corp
  • Snap-On Incorporated
  • Tooltechnic Systems LLC (Festool)
  • Chervon North America Inc. (OEM supplier to brands such as Craftsman, Kobalt, and Masterforce)
  • Positec Tool Corporation et al (Rockwell and Worx; OEM supplier of Performax)
  • Richpower Industries Inc. (Genesis, PowerSmith, and Apprentice)
  • Sunrise Global Marketing LLC (Greenworks tools and OPE)
  • The complaints contain identical language, varying only where defendants are named and the models said to infringe Milwaukee patents are listed. And that would be every cordless Lithium-Ion tool from the companies named in the lawsuits.

According Milwaukee, it holds three patents (7,554,290; 7,944,173; 7,999,510) that give it the exclusive right to make “multi-cell Li-Ion packs that can produce an average discharge current greater than or equal to approximately 20 amps”. The patents also contain language describing the use of terminals in the tool and battery and the use of a lock to hold the battery in place—though it’s hard to believe these features are the focus of the suit because both were in use long before Milwaukee got into the cordless power tool business.

Milwaukee appears to be saying “We were the first to put Li-Ion cells in battery packs and we patented it, so we’re the only ones who are allowed to do it”. It’s unclear how an average discharge rate of 20 or more amps figures into the argument.

I contacted Milwaukee and asked what the suit was about. Their spokesperson was unable to comment on pending legal matters and referred me to the general counsel of their parent company (TTi). I sent that person the following three questions:

1) Is Milwaukee suing those 8 companies merely for putting lithium-ion cells into the battery packs of tools—or is there some more technical explanation for how they are alleged to have infringed the three patents?

2) The suit mentions packs with an output equal to or greater than 20 amps. Is 20 amps some kind of magic number?

3) Finally, if those 8 companies infringed Milwaukee patents by producing/selling lithium-ion battery packs—what about other big companies such as Bosch, DeWalt, and Makita. Aren't they doing the same thing as the others?

[Author's note: Makita should not have been included in the question above. In 2009 Milwaukee sued Makita and Hitachi for infringing its patents on Lithium-Ion and both cases were settled out of court]

TTi’s general counsel said she was unable to answer specific questions about pending legal matters but did say:

“…Milwaukee led the way in li-ion technology for power tools and has obtained many patents protecting its pioneering inventions. Milwaukee revolutionized the power tool industry when it launched its li-ion V28 line of cordless power tools in 2005. Innovation is at the heart of our business, and we vigorously protect our intellectual property against all infringements. We have taken and will continue to take appropriate action against anyone infringing our patents. This action can take the form of lawsuits or amicable negotiations to resolve the matter. Where possible, we have sought the latter, but where not possible, we must pursue court action.”

Part of the counsel’s response is a restatement of the “background facts” section of the complaints filed against the 8 tool companies. The background facts are Milwaukee's version of how Lithium-Ion power tools came to be, which I have  boiled down to the following points:

  • Prior to the introduction of Lithium-Ion power tools, NiCad tools had hit a plateau in terms of performance and runtime.
  • The highest voltage NiCad tools were heavy. Increasing their runtime and power would mean making them heavier still, resulting in tools that were impractical to use.
  • Prior to the introduction of the V28 line, it was generally believed Lithium-Ion cells were unsuitable for use in power tools.
  • Milwaukee’s V28 tool line (introduced in 2005) was the first to make use of Lithium-Ion battery cells.
  • Soon after, “Li-Ion became the de facto industry standard” and every competitor in the power tool industry “adopted Milwaukee Tool's inventions and transitioned, at least in part, to the use of Li-Ion powered battery packs in their handheld cordless power tools.”

The operative text in the section above is “adopted Milwaukee Tool’s inventions”. If any of these cases go to trial it will be up to a jury to decide if putting Li-Ion cells in a battery pack is an “invention” covered by patent law. It will be interesting to see what happens. A win by Milwaukee could mean some companies would be barred from producing or selling Li-Ion tools if they were unable to come to a financial agreement with Milwaukee.

Should Milwaukee succeed in these actions against smaller power tool companies it's hard not to wonder what might happen if they filed the same kind of suits against major competitors such as Bosch, DeWalt, and Makita. Could we someday live in a world where there was only one brand of Li-Ion power tools or where all brands had to pay royalties to Milwaukee?

[Author's note: The question in the sentence above is off base. Makita settled a similar suit with Milwaukee in 2009 and it still makes Lithium-Ion tools. It's reasonable to assume something similar might happen with some of the companies now being sued by Milwaukee and that some of the companies that haven't been sued may have already cut deals with Milwaukee. For more on these possibilities see: Readers Comment: Here's What You Missed In Covering Milwaukee's Lithium-Ion Lawsuits.]