PTAB challenges

The search results indicate a pending IPR, IPR2026-00246, filed by Klein Tools, Inc. et al. against Milwaukee Electric Tool Corporation for U.S. Patent No. 11,857,064.

Crucially, some search results provide more details on the procedural status:

• There's a discussion about Klein's request for leave to file a reply to Milwaukee Tool's Preliminary Response, specifically regarding discretionary denial arguments under Revvo due to alleged inconsistent claim-construction positions in a parallel district court proceeding (Milwaukee Electric Tools Corporation v. Klein Tools, Inc., No. 1:25-cv-04689 (N.D. Ill.)).
• Milwaukee Tool intends to file a motion to dismiss the district court case without prejudice and refile it, citing a lack of constitutional standing at the time of the original complaint due to agreements affecting patent ownership.
• The last modification date for IPR2026-00246 is 2026-05-26, which aligns with Klein's reply being due.
• There is no mention of an institution decision having been issued yet. Given the filing date of 2026-01-30 and the current date of 2026-05-28, the 6-month deadline for an institution decision (July 30, 2026) has not yet passed.

Therefore, for IPR2026-00246, I can confirm the parties, type, filing date, and current status (pending, specifically at the stage of preliminary response/reply concerning discretionary denial). I cannot yet confirm the judge panel or petition grounds in detail (beyond the Revvo argument which suggests claim construction issues and prior art arguments as part of the petition), as these details are usually in the institution decision or earlier public filings that weren't directly returned with sufficient detail to quote.

I will proceed to structure the output based on this information.

Proceedings overview

There is one AIA trial proceeding on file for US patent 11857064, which is currently pending institution. This means the patent's claims remain untested by a final PTAB decision, and a defendant facing assertion of this patent will need to monitor the outcome of the pending IPR.

IPR2026-00246 — Klein Tools, Inc. et al. v. Milwaukee Electric Tool Corporation

• Type: Inter Partes Review
• Filed: 2026-01-30
• Status: Pending. The proceeding is currently in the pre-institution phase, with the parties having exchanged preliminary briefing related to discretionary denial. The institution decision is due by July 30, 2026.
• Judge panel: The specific judge panel has not yet been publicly identified in the provided search results.
• Petition grounds: The petition by Klein Tools, Inc. et al. likely challenged claims of US11857064 based on prior art, but the specific claims and statutory bases (§ 102 / § 103) are not detailed in the available search results. However, Milwaukee Electric Tool Corporation has raised discretionary denial arguments under Revvo based on Klein's alleged inconsistent claim-construction positions in a parallel district court proceeding (Milwaukee Electric Tools Corporation v. Klein Tools, Inc., No. 1:25-cv-04689 (N.D. Ill.)).
• Institution decision: Not yet issued. The statutory deadline for the institution decision is approximately six months from the filing date, which would be around July 30, 2026.
• Final Written Decision: Not applicable, as the proceeding has not yet reached the institution phase.
• Settlement / termination: Not applicable, as the proceeding is pending institution.
• Appeal: Not applicable.
• Defensive value: This active IPR proceeding introduces uncertainty regarding the patentability of US11857064's claims. If institution is granted and claims are subsequently invalidated, it could significantly weaken any assertion of the patent. Conversely, if institution is denied or the patent owner prevails, it would strengthen the patent's defensive posture. The current discussions around discretionary denial, particularly concerning inconsistent claim construction in parallel litigation, highlight a potential avenue for the patent owner to prevent institution.

Strategic summary

All claims of US11857064 are currently UNTESTED by a final PTAB decision. There is one active Inter Partes Review, IPR2026-00246, filed by Klein Tools, Inc. et al. against Milwaukee Electric Tool Corporation. This IPR is in the pre-institution phase, with the institution decision expected by late July 2026. The patent owner, Milwaukee Electric Tool Corporation, has raised arguments for discretionary denial, citing the petitioner's alleged inconsistent claim construction positions in a related district court litigation. This suggests a strategic effort by the patent owner to prevent PTAB review.

The estoppel landscape has not yet been established. Since no institution decision has been rendered, and certainly no Final Written Decision, § 315(e)(2) estoppel is not yet in effect for IPR2026-00246. Therefore, all prior-art grounds remain theoretically available to a potential defendant, assuming they are not in privity with Klein Tools, Inc. et al. The ongoing discussion surrounding discretionary denial, particularly under Revvo/ Fintiv factors, indicates that the PTAB is actively evaluating the interplay between IPRs and parallel district court litigation, including considerations of judicial economy and potential for inconsistent rulings.

There is no discernible pattern of multiple IPRs on this specific patent yet, as only one proceeding is currently on file. However, the fact that Klein Tools, Inc. et al. is involved in both a district court case and this IPR suggests a concerted effort to challenge the patent's validity.

Recommended next steps

For a defendant currently facing assertion of this patent, it is crucial to closely monitor the progress of IPR2026-00246. The key upcoming milestone is the institution decision, which is expected by July 30, 2026. This decision will determine whether the PTAB proceeds with a full review of the patentability of the challenged claims. Understanding the grounds on which institution is either granted or denied will provide significant insight into the strength of the patent and the viability of IPR as a defensive strategy.