Patents and protective rights

Nearly every German patent claim turns on one hinge: dadurch gekennzeichnet, dass. Everything before it is der Oberbegriff, the features already known; everything after it is das kennzeichnende Merkmal, the part that is new. The hinge itself is a piece of ordinary grammar. When a verb or participle takes a preposition — gekennzeichnet durch, sich freuen auf, bestehen in — and what follows is a whole clause rather than a noun, German does not drop the preposition. It fuses it with da-, adding an r before a vowel, and parks the result in the main clause as a placeholder: dadurch, darauf, darin. The dass-clause then fills it. With a plain noun the placeholder disappears: gekennzeichnet durch einen Hebel. Read a claim with that in mind and the placeholder tells you exactly where the invention starts.