How Does the UPC Assess Equivalence? — Reflections on Wonderland v. Cybex

The UPC has added another noteworthy decision on patent infringement by equivalence.

On 27 May 2026, the Local Division Düsseldorf delivered its judgment in Wonderland v. Cybex (UPC_CFI_807/2024, UPC_CFI_334/2025). The Court upheld the validity of the patent but found that the accused products infringed neither literally nor by equivalence.

The judgment is particularly interesting because it expressly endorses the four-step framework for assessing equivalence first developed by the Local Division The Hague in Plant-e v. Arkyne and subsequently applied in Washtower v. BEGA. More importantly, the Düsseldorf panel provides one of the UPC’s most detailed discussions to date of how that framework should be applied in practice.

For practitioners following the development of UPC case law, the decision offers useful guidance on several aspects of the Court’s approach to infringement by equivalence.

1. Düsseldorf Endorses the Four-Step Framework Developed by the Local Division The Hague

The UPC Court of Appeal has not yet established a uniform test for infringement by equivalence.

In Plant-e v. Arkyne, the Local Division The Hague formulated a four-step framework, which it later applied again in Washtower v. BEGA.

In Wonderland v. Cybex, the Düsseldorf Local Division expressly endorsed that approach, stating:

“The criteria set out by the Local Division The Hague form a coherent whole.”

The Court therefore considered the four-step framework suitable for assessing infringement by equivalent means and found no reason to adopt a different standard in the present case.

Under this framework, the following questions are examined:

1. Does the variant perform essentially the same technical function as the claimed feature (technical equivalence)?

2. Would extending protection to the variant provide fair protection for the patentee, taking into account, among other things, whether the equivalent would have been obvious to the skilled person from the patent?

3. Would such an extension remain consistent with reasonable legal certainty for third parties?

4. Is the alleged equivalent itself novel and inventive over the prior art (the Formstein/Gillette defence)?

Although this is not the first UPC decision to adopt the Hague framework, Wonderland is one of the clearest illustrations of how the Court applies the first three steps in a fully reasoned judgment.

2. The Same Overall Technical Objective is Not Enough

Perhaps the most significant part of the judgment concerns the Court’s discussion of technical equivalence.

The patentee argued that the accused product merely rearranged the locations of several claimed components.

For example, the claims required the locking pin to be disposed on the wheel bearing assembly, whereas the accused embodiment located the locking pin on the seat. Likewise, the operating member was coupled to the seat rather than the wheel bearing assembly, and the cavity and clasping mechanism were likewise relocated.

According to the patentee, these modifications did not change the overall technical objective of the invention, namely providing a stable connection between the rotatable and non-rotatable parts while allowing selective locking of the swivel mechanism.

The Court disagreed.

Referring to Headnote 2, the Court explained that a patentee cannot establish technical equivalence simply by focusing on the overall objective of the invention. Instead, it must identify the function performed by each substituted claim feature and explain why the modified feature performs essentially the same function.

This was particularly important because the patent expressly claimed not only the components themselves, but also their specific arrangement. The Court observed that the patentee had not explained why the claimed arrangement—such as locating the locking pin and operating member on the wheel bearing assembly, and placing the cavity and clasping mechanism within the wheel bearing assembly—was functionally equivalent to the modified arrangement adopted in the accused product.

The Court therefore concluded that technical equivalence had not been established.

This clarification, now reflected in Headnote 2, is likely to become an important reference point for future UPC cases involving equivalence.

3. Why the Variant Was Not Obvious to the Skilled Person

The Court next considered the second step of the analysis: fair protection for the patentee.

The patentee argued that the accused embodiment could readily be derived from the patent because the skilled person would simply reverse the operating direction of the locking pin and relocate the relevant components. During the oral hearing, the patentee further argued that the claimed arrangement merely had to be turned by 180 degrees, without altering its internal working principle.

The Court was not persuaded.

In its view, arriving at the accused embodiment required several claimed components to be rearranged simultaneously, including the locking pin, operating member, cavity and clasping mechanism. That went well beyond replacing an individual claim feature with an equivalent one.

The Court therefore held, as stated in Headnote 3, that:

“In general, it is not obvious to a skilled person how to apply the equivalent element if a complete redesign of the claimed device is required.”

Importantly, the Court did not hold that every structural modification constitutes a complete redesign. Rather, it reached that conclusion on the particular facts before it, where multiple interrelated structural relationships defined by the claims had to be altered simultaneously.

4. The Court Also Considered Legal Certainty

Another noteworthy aspect of the judgment is that the Court continued its analysis even after concluding that the first two requirements were not satisfied.

The Court went on to consider reasonable legal certainty for third parties.

It observed that the patent did not merely claim a general technical concept or functional result. Instead, the claims specified a particular structural arrangement, including where the locking pin, operating member, cavity and clasping mechanism were located.

Accordingly, a skilled person reading the patent would understand that these structural relationships formed part of the claimed technical solution rather than representing arbitrary design choices.

Extending protection to an embodiment that altered several of those structural relationships would therefore undermine the reasonable expectations of third parties as to the scope of protection.

The Court therefore concluded that the third step of the Hague framework was likewise not satisfied.

5. How does Wonderland v. Cybex Fit into the UPC’s Developing Case Law?

Several earlier UPC decisions have already addressed infringement by equivalence, including Plant-e v. Arkyne, Washtower v. BEGA, Ballinno v. UEFA, OrthoApnea, DISH v. AYLO, N.J. Diffusion v. Gisela Mayer and Hartmann Packaging v. Omni-Pac.

Among them, Plant-e v. Arkyne was the first UPC decision to formulate and apply a four-step framework for assessing infringement by equivalence, ultimately finding infringement. Washtower v. BEGA subsequently applied the same framework in preliminary injunction proceedings and provisionally concluded that replacing the claimed metal L-shaped retaining strip with a plastic one constituted an equivalent implementation.

Not all subsequent decisions, however, have required a detailed analysis of every step of the framework. In cases such as OrthoApnea, DISH v. AYLO, N.J. Diffusion v. Gisela Mayer and Hartmann Packaging v. Omni-Pac, the courts concluded that the accused embodiments did not satisfy the requirement of technical equivalence. As a result, the judgments primarily focused on that aspect of the analysis.

Against that background, Wonderland v. Cybex is noteworthy because it is the first decision of a German Local Division to expressly endorse the four-step framework developed by the Hague Local Division. More importantly, it further clarifies why establishing the same overall technical objective is insufficient to demonstrate technical equivalence and why, in general, a variant requiring a complete redesign of the claimed device will not be regarded as obvious to the skilled person.

Whether the Court of Appeal will formally endorse the Hague framework—or further refine its individual elements—remains to be seen.