Patents in window manufacturing: the 1970s block-system

In 1974, the company Götz from Deggendorf, Germany, launched a new aluminium window construction on the market, known as window-block-system. Its striking features were a concealed window vent, invisible from the outside regardless of its opening type, and an extremely narrow face width of the external outer frame. The system combined favourable climatic properties and sophisticated design requirements. For this invention, Götz secured extensive industrial property rights. However, a look at the contemporary window market shows a similar design previously filed for patent by the Munich-based company Schöninger, and a predecessor for both inventions can be found at the end of the 1960s. The following analysis of window-block-designs from the 1960s to 1980s reveals that numerous manufacturers created supposedly new but rather similar products and were economically successful both with and without property rights. Learning from the exemplary case of window-block-systems, the paper discusses the industrial property rights strategy of various window manufacturers as well as their inventorship and the role and relevance of patents and utility models for innovation in the building sector.