The partial-problems approach to inventive step is a well-known part of European patent practice, not least as it is used routinely by the EPO. The UPC’s Central Division (Munich) has now also applied this approach in UPC_CFI_836/2024 concerning EP4019790, which relates to a nail for use in a nail setting device. The claim in question combined two separate distinguishing features: a nail‑tip angle greater than 40°, intended to reduce the risk of the nail receiving material from splitting when the nail is driven in, and longitudinal grooves on the nail shaft, intended to increase pull‑out resistance after insertion. The court held that these features addressed two technically independent problems that did not exhibit any functional interaction or synergy.
Reducing splitting relates to the driving phase, whereas improving pull‑out strength relates to performance once the nail is already set.
Because the features solved different problems, the court evaluated each partial solution separately in line with established European practice on aggregations of features. Applying the partial-problems approach, the court held that these two distinguishing features solve independent problems without any synergistic interaction. Because the claim was therefore a mere aggregation of features, the contribution each feature makes to inventive step can be assessed in isolation from the other feature. The court found that both the selection of the tip angle and the use of longitudinal grooves were both independently obvious in light of a prior art and general technical knowledge. As a result, the claim lacked inventive step as a whole.


