Wittenstein SE v. Vestas Wind Systems A/S

This is a revocation action (Action no. UPC 523/2025) before the Central Division (Section Munich) of the Unified Patent Court. The Claimant, Wittenstein SE (a German company based in Igersheim), brought the action on 12 June 2025 against the Defendant, Vestas Wind Systems A/S (a Danish company based in Aarhus). The patent at issue is European Patent EP 4 226 039 B1, entitled 'Wind turbine power transmission system,' which is based on international patent application WO 2022/073571 filed on 23 July 2021 and claims priority from Danish patent application DK PA202070677 of 6 October 2020. The mention of grant was published on 18 September 2024. The Claimant had also filed a notice of opposition with the EPO Opposition Division, whose oral proceedings on 24 June 2026 resulted in the patent being maintained in amended form (corresponding to the Defendant's auxiliary request 1), though that decision had not become legally binding. The panel consisted of Presiding Judge András Kupecz (also judge-rapporteur), legally qualified judge Daniel Severinsson, and technically qualified judge Kerstin Roselinger. An oral hearing was held on 8 July 2026, and the decision was issued on 2 September 2026.

The Claimant argued that the Patent was invalid on multiple grounds under Art. 65(1) and (2) UPCA in combination with Art. 138(1)(a)–(b) and (e) EPC. Specifically, the Claimant contended that the Patent lacked novelty (Art. 54 EPC), did not involve an inventive step (Art. 56 EPC), and did not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. Additionally, the Claimant raised an entitlement ground under Art. 138(1)(e) EPC, alleging that the patent proprietor was not entitled to the patent under Art. 60(1) EPC. The patent contains 22 claims, with claim 1 being an independent claim directed to a wind turbine with a specific gear system comprising a fixed ring gear, an input member with radially movable tooth segments, and a central output member with an eccentric profile. Claims 2–22 are dependent claims adding various specific features.

The Court issued two key headnotes. First, regarding the entitlement ground under Art. 138(1)(e) EPC, the Court held that this provision should be interpreted as meaning that the proprietor does not have any rights to the patent. The burden of presentation and proof for facts establishing that the proprietor is not entitled lies with the claimant. It is therefore not sufficient for this ground of revocation to succeed that a claimant merely demonstrates that it has rights to parts of the subject-matter disclosed in a patent (e.g., as a co-inventor or co-inventor's successor in title). Second, regarding dependent claims, the Court held that dependent claims are part of the patent and may be used as fall-back positions in revocation actions. At least in a stand-alone revocation action, where no infringement claim has been brought and it is not yet clear which claims a patent holder may decide to rely on, a claimant may have a legitimate interest in having the validity of dependent claims assessed, even if the independent claim is deemed valid. Although the Court is not generally required to take a decision regarding dependent claims in such a situation, it should at least have the discretion to do so if considered appropriate based on the circumstances of the case.