Socket wrench

Berlin key with holder

The pass-through key (also: Berlin key , double key ; English : Berlin key ) is a key with two identical beards . After the lock has been unlocked, the key must be pushed through the lock in order to pull it out of the lock on the other side with a twist, which locks the lock again. The pass-through key therefore forces the user of a passage door, which is to be kept locked, to lock it again immediately after passing through or to leave his key in the door. Such door locks with compulsory locking were the rule for the front doors of the Berlin tenements with backyards until the general introduction of house intercoms .

The key was invented by the Berlin master locksmith Johann Schweiger and registered for a patent by his company, Albert Kerfin & Co GmbH in 1912 (at that time still in Berlin-Kreuzberg , Adalbertstraße ). For many years the company was based in Berlin-Wedding and is now in Berlin-Biesdorf . Nowadays the socket key is only used sporadically in old building areas with corresponding doors and gate entrances, but is now a popular Berlin souvenir. A further development took place in the case of keys for cylinder locks , but here only for doors that can be accessed from one side.

literature

• Bruno Latour : The Berlin Key. botopress, Berlin 2015. From the French and with a comment by Gustav Roßler (Social Realization. Keys, People, Things) , ISBN 978-3-946056-00-3 .
• Bruno Latour : The Berlin Key . Explorations of a lover of science. Berlin: Akademie Verlag 1996, ISBN 3-05-002834-3 .

Web links

• Jens Sethmann: Against the defaulting and forgetful. The triumph of the double key. In: tenant magazine. Ed. vd Berliner Mietervereinigung, Berlin 11/2005, p. 19 f.
• The Berlin key in a report by Karambolage on ARTE on March 26, 2006 (video version on Vimeo , uploaded by the producer of the film: Der Berliner Schlüssel / The Berlin Key ).
• Website of the manufacturer Kerfin .
• Berlin through lock (Kerfin lock) . Explanations at Wiki.koksa , accessed on October 2, 2019.

Individual evidence

1. ↑ Petra Ullmann: Almost 90 years ago a craftsman from Weddingen invented the push-through key. In: Der Tagesspiegel , March 8, 2000, accessed on August 19, 2013
2. ↑ Jens Sethmann: The triumphant advance of the double key . In: MieterMagazin , November 2005, accessed on August 19, 2013
3. ↑ Compulsory closure with two beards. In: taz , January 11, 2016