The legal figure of equivalence and the associated question of infringement of a patent claim outside the scope of literal protection are among the most challenging tasks of patent law advice. On one hand, this is due to the case law, which is in a state of flux, and on the other hand, due to the evaluation required in individual cases as to whether a solution outside the literal sense can still be assigned to the scope of protection of the patent. This allocation and thus the assumption of an equivalent solution in the legal sense require three prerequisites: 1) a technical equivalent effect, which 2) is obvious to the person skilled in the art and 3) which the person skilled in the art considers as an equivalent solution based on the meaning of the patent claim. With the current “Kranarm” (crane arm) decision, the BGH does not break any new ground. Rather, the BGH confirms its previous case law on the assessment of equal effect. With this decision, the BGH contributes to legal certainty and thereby strengthens the position of both patent owners and competitors.
The inclusion of equivalent solutions in the scope of protection serves to adequately protect the inventive step. However, this is at the same time in tension with the requirement of legal certainty. In order to balance these conflicting interests, the case law requires that the meaning of the patent claims forms the decisive basis for determining the scope of protection (BGH, judgement of 12 March 2002, X ZR 168/00 – Schneidmesser I, GRUR 2002, 515, 517). Accordingly, it is demanded by case law that a solution deviating from the literal sense, which is assigned to the scope of protection equivalently to the literal solution, must be oriented towards the patent claim. This means that the skilled person must be able to find the modified but objectively equivalent means for solving the problem with considerations that are oriented towards the meaning of the teaching protected in the patent claim (BGH – Schneidmesser I, GRUR 2002, 515, 517).
Initial situation
In the specific case “Kranarm” the BGH was faced with a decision of the Munich Higher Regional Court (OLG), in which the OLG had assumed an equivalent infringement of the patent in suit. The patent in suit (EP1889808B1) concerns a crane arm with an attachment device for implements, which is equipped with swivel joints in the manner of a cardan joint. The patent in suit addresses the technical problem of constructing the cardan joint as stable as possible overall and allowing easy access to the connections for the hose lines without impairing the protection of the hose lines from external damage (BGH – Kranarm, para. 13).
As a solution to the problem, the patent claim 1 in suit provided, inter alia, that the hose lines (7), which run from the crane arm to the implement past the cardan joint, run “between the two pivot bearings (4a and 4b) of the pivot joint (4) on the crane side” (feature 3.1 of the feature structure of the BGH, para. 13) and “offset in the direction of the axis of rotation (y) of the pivot joint (5) on the working side, past this pivot joint” (feature 3.2). For a better understanding, the embodiment example according to Figure 4 is shown below:(picture shown in the newsletter)
The OLG found that the impugned embodiments 1 and 2 did not realise feature 3.1, as the hose lines did not run between the two pivot bearings (4a and 4b) of the crane-side pivot joint (4) on the crane side, but around a component that connects the two pivot bearings and fills the space between them (BGH – Kranarm, para. 17). This is clearly visible in the following illustration of the contested embodiment 2 (BGH – Kranarm, para. 4; emphasis added in red): (picture shown in the newsletter)
However, the OLG Munich acknowledged a realisation of patent claim 1 by equivalent means and – in opposition to the District Court – assumed an equal effect. It is true that the protection of the hose assemblies intended by feature 3.1 was achieved only to a limited extent. However, this did not prevent a equivalent effect, as the inventive effect of protecting the hoses from damage by external influences was still achieved in decisive manner by the fact that the hoses, after being guided around the component between the pivot bearings, were subsequently guided again on the side of the attachment device facing the crane arm between the two plate-shaped support devices running vertically to the axis of rotation (BGH – Crane arm, para. 18).
Decision of the BGH
The BGH did not allow this reasoning to suffice, so that an equal effect could at least not be assumed on the basis of the argumentation of the OLG Munich. The BGH stated that the deciding factor for the question of equal effect was which individual effects the features according to the patent provided – individually and as a whole – for solving the problem underlying the patent claim and whether these effects were achieved by other means in the attacked embodiment (BGH – Kranarm, para. 42 f.). An equal effect would not require that the deviating design obtains the effect according to the invention without any restriction. It was sufficient that the required effect was achieved by modified means only to a limited extent. The assumption of an equal effect could already be considered appropriate if the effect according to the invention was essentially achieved, i.e. to a practically still considerable extent. For this purpose, the effect according to the patent and a weighting of the deficits found in the challenged embodiments based on this were relevant (BGH – Kranarm, para. 47).
With regard to the present dispute, the BGH stated that the protection of the hose lines in the area of the two swivel joints was guaranteed by features 3.1 and 3.2. Against this background, it was not sufficient – in contrast to the assumption of the OLG – that the hose lines were only protected from external influences in the further course by components of the crane arm, but not in the area of the swivel joint on the side of the crane arm (BGH – Crane arm, paras. 44-46, 48). As the previous findings did not support the assumption of an equal effect, but at the same time could not be ruled out, the BGH referred the case back to the OLG (BGH – Crane Arm, para. 49 ff.).
Consequences for legal practice
The decision does not change the previous perception. It will remain the case that the assessment of an equal effect requires a precise elaboration of the effects according to the invention and their assignment to the relevant claim features and subsequently to the modified, possibly equivalent means. However, with the confirmation of its previous case law, the Federal Supreme Court contributes to legal certainty, which is of great importance (not only) for legal counselling practice.
