![](https://www.sl-rasch.com/wp-content/uploads/2019/07/SL_Rasch_U10_Prototyp_01_Mobile.jpg)
Convertible Umbrella
Prototype of an umbrella with a folding arm system
In 1988, SL Rasch developed the prototype of a convertible umbrella as a study for the potential shading system on the large piazza around the Prophet’s Mosque in Medina. This was the first umbrella with a folding arm system, and its mechanism permits a maximum span of more than 12 metres. The structure is designed for wind speeds of up to 155 kilometres per hour – in both deployed and folded position. An anemometer ensures the umbrella is prevented from opening or closing when a strong wind is blowing. After being temporarily installed in front of the UN building in San Francisco (USA), the prototype now stands on private property in Germany.
![SL_Rasch_U10_Prototyp_02](https://www.sl-rasch.com/wp-content/uploads/2019/07/SL_Rasch_U10_Prototyp_02.jpg)
![SL_Rasch_U10_Prototyp_03](https://www.sl-rasch.com/wp-content/uploads/2019/07/SL_Rasch_U10_Prototyp_03.jpg)
![Innovative mechanism - The prototype was the first umbrella by SL Rasch with a folding arm system.](https://www.sl-rasch.com/wp-content/uploads/2019/07/SL_Rasch_U10_Prototyp_Skizze.jpg)
The prototype was the first umbrella by SL Rasch with a folding arm system.
![Unvarying height - If the arms fold up as the umbrella closes, its overall height remains unchanged.](https://www.sl-rasch.com/wp-content/uploads/2019/07/U105_NEU-1.jpg)
If the arms fold up as the umbrella closes, its overall height remains unchanged.