Hazard function
According to DIN 18252 , the danger function ("GF") or emergency and danger function means that "in the case of a profile double cylinder , it can be closed from the opposite side with a second associated key despite the key being turned on one side". Some manufacturers call the Emergency function also BSZ function ( b eidseitig s chließbarer Z ylinder ) or priority function . The latter, however, is not completely identical: only the outside is given priority, i.e. H. If there is a key there, it cannot be locked or unlocked inside.
The hazard function therefore allows double locking cylinders to be actuated with one key on both sides even if a key is already inserted on the other side. In an emergency, a door can then be opened from the outside or inside using a second key without breaking the lock.
The hazard function is required to get to helpless trapped people or to get back to locked rooms after being unintentionally locked out. This is particularly useful for apartments for the elderly and in general if there is no second access or if it cannot be easily accessed or opened, which applies to most apartments.
Cylinders with the hazard function are less robust than simple profile cylinders , as the mechanism in the locking nose (clutch) consists of several small springs and sensitive pawls.
According to DIN 18252, the coupling is the "component in a profile cylinder that connects the cylinder core actuated by the key to the lock bit in a rotationally fixed manner". In the case of double cylinders without a hazard or free-wheel function, the clutch does not allow the cylinder to be closed from the opposite side of the cylinder if the key is turned on one side.
Constructions are also common in which the tip of the key engages in the coupling and establishes the transmission with a positive fit. If the key wears out in the area of the tip, it can slip out of the coupling and the lock can no longer be opened as intended. For doors with a high frequency of use, the hazard function is therefore often foregone. The hazard function may also be unsuitable for multi-point locks and armored bolts, where keys and profile cylinders transmit higher torques.
As a variant, special cylinders with a so-called hazard key function can only be unlocked from the outside with a special hazard key. Depending on the manufacturer, the hazard key has a specially shaped tip, spring-loaded spike or something similar.
According to DIN 18252, the freewheel function ensures that "when the key is removed, the two cylinder cores of the profile double cylinder are not connected to the lock bit in a rotationally fixed manner". This means that the locking nose can be turned in a profile cylinder with a freewheel even without a key.
This means that a lock with a free- swing function can be operated by simply pressing a door knob or a panic bar . This is made possible by the special design of the locking nose, which is otherwise set in motion by a key and triggers the locking process. Since the free swing function works without a key, it is particularly suitable for fire doors.
This function may be necessary with panic door locks in order to enable the bolt to be pulled back when the fitting (e.g. door handle) is operated ("escape door function"). It is also common to combine the hazard function with freewheeling .
Footnotes
- ↑ a b c Realization of the inevitability of doors along escape routes and fire doors , p. 11/13; In: VdS.de. Accessed January 2020
- ↑ Security glossary: locking systems ; In: Abus.com. Accessed January 2020