The "founding father" of the L shape is the Frankfurt model from the 1920s. In the 80s, the door handle was used in the German Museum of Architecture in Frankfurt, where the name for the door handle probably comes from. A second approach is based on a different name origin for the handle: The L-shape was designed by the Frankfurt architect Ferdinand Kramer and thus came to its name. Since 1925 the door handle has been mass-produced in the Frankfurt model.
Even if the history of its origin is unclear: the door handle and the city of Frankfurt are closely connected. According to records, four different shapes are attributed to the door handle of the Frankfurt model. First, the L-shaped handle was produced from white bronze and nickel silver. This was followed by a switch to cast iron, aluminum and finally stainless steel. From 1920-1940, the Frankfurt shape for the interior door was the most commonly used handle for the room door.