What we learned from the mushroom: a patent between technological invention and standards

This article focuses on the Geilinger shear-head reinforcement – an invention of the Swiss company Geilinger – and traces its impact on construction products and the role of patents in its development and dissemination. In the 1960s, the engineer Stanislaw Bryl and the architect Ernst Rüeger applied for two patents for Geilinger & Co. Both patents were issued for columns that support a reinforced concrete ceiling. The invention allows the structural elements that absorb the shear forces to be fully embedded in the flat slab. The ‘Geilinger steel mushroom’ – as the invention was called – is still used today in skeleton construction, for example for the Roche Towers in Basel by Herzog & de Meuron (2012–2015/2017–2022). Using the Geilinger shear-head reinforcement as an example, the article analyses the different factors that influenced the development of building products at the time – the technical progress in the calculating methods, the revision of the standards, and the patent strategy of the company itself. The focus is particularly on the conflict between novelty and utilisation of the invention. The article demonstrates that the strategy of the company’s patents was to disseminate the Geilinger ‘steel mushroom’ as a construction product to establish a monopoly.