The dispute was brought by Yellow Sphere Innovations GmbH and inventor Erwin Härtwich against caravan manufacturer Knaus Tabbert AG.

The claimants alleged that the defendant’s caravans, marketed using “Fibre Frame” technology, incorporated structural elements falling within the scope of the patent.

The defendant denied infringement and responded with a counterclaim for revocation of the patent.

The patent

The patent concerns a vehicle frame structure, suitable for caravans or similar vehicles. The invention aims to provide lightweight but structurally robust frame elements.

Claim 1 is directed to a frame for a vehicle with at least one structural part. The claim includes several key features, some of which are defined in terms of a method of manufacture. In particular, the claim requires that:

• the structural part is manufactured as a casting in a casting mold; and
• the mold reproduces the three-dimensional outer shape of the structural part.

This introduces the product-by-process issue: whether the claim is limited to products actually manufactured by that process, or whether it covers products having the resulting characteristics regardless of how they were made.

The court therefore had to address how process language in a product claim should be interpreted when assessing patent infringement.

Product-by-process claims

The court clarified the legal nature of product-by-process claims in a way that aligns closely with established European Patent Office  (EPO) practice.

According to the court, such claims are characterised by the fact that the technical contribution of the invention generally lies not in the manufacturing process itself, but in the properties imparted to the resulting product. The process language therefore serves primarily as a means of defining the product.

When assessing infringement, the decisive factor is therefore how the person skilled in the art would understand the information on the manufacturing process and what conclusions they would draw about the structure or characteristics of the resulting product. The focus is on the technical features of the product implied by the process, rather than on whether the process was actually carried out.

This reasoning had a direct impact on the defendant’s non-infringement arguments. The defendant attempted to avoid infringement by pointing to differences in its production method, including the use of multiple moulds and additional processing steps. However, under the court’s interpretation, such differences are not necessarily decisive.

Instead, the relevant question becomes whether the accused product possesses the structural characteristics that the claimed process would produce. If the person skilled in the art would infer that the product necessarily has those characteristics, the claim may still be infringed even if the exact manufacturing route differs.

The decision therefore confirms that, at least in principle, product-by-process language does not automatically restrict protection to products made by the specified process. Rather, the process wording functions as a tool to define the product’s technical features where those features cannot easily be expressed in purely structural terms.

The court also recognised an important qualification to this principle. Where the manufacturing process leads to identifiable properties that can only be achieved through that specific process, the patent may in practice be limited to products that can be manufactured using that process. In the present case, however, the court did not consider this situation to arise and found that infringement had occurred.

Conclusion

Although the case involved a relatively specific technology in the caravan industry, the court’s reasoning has wider relevance.

The decision signals that the UPC is likely to interpret product-by-process claims in a manner broadly consistent with established European patent law principles. In practice, the analysis will focus on the product’s technical characteristics as understood by the person skilled in the art, rather than the specific manufacturing method which has been used.

For businesses operating in sectors where manufacturing processes play an important role in defining products (such as advanced materials, chemical engineering, or composite structures) this decision provides important guidance of how such claims may be assessed before the UPC.

Case details at a glance

Jurisdiction: UPC
Decision level: Düsseldorf Local Division
Parties: Erwin Härtwich, Yellow Sphere Innovations GmbH v Knaus Tabbert AG
Citation: ORD_68984/2024
Date: 10 April 2025
Decision: dycip.com/upc-ord-68984-2024