The quality of a lock is judged by how easy it is to prevent unwanted access. However, there are situations where the presence of a lock can represent a problem even for those who are authorised to gain access. This is especially the case where you need to quickly gain access to a house or a room to rescue a person closed inside who is unwell and unable to open the door. Indeed, with common double cylinder locks, if the key has been left inserted in the keyhole inside the house one is often unable to open the door from the outside, even having another correct key. To avoid this situation, which can result in the loss of valuable time in the event of an emergency, there are cylinders designed specifically to be opened (with the key!) from the outside even if a key has been left inside.
Cylinders with emergency function and frictioned cylinders
If you exclude the cylinders for bathroom doors, which often have, on the outside, a round plate with a slot for the introduction of a coin which can be used for unlocking, there are two possible solutions with double cylinders:
- Cylinders with emergency function, which have a set installation direction such as the Viro 700 series cylinders, the mechanism of which allows opening with a key from the outside even if another key has been left inserted on the inside.
- Frictioned cylinders, which can be installed either one way or the other such as the Viro Palladium, which allow opening from either side, even if a key is inserted in the other side.
Less risk of being locked out
Almost everyone, at least once in their lives, has been locked out of their house. It often happens because you have lost your keys, but it can even happen if you have your trusty bunch of keys with you. With conventional cylinders, if a key has been left inside and the plug is not perfectly aligned, perhaps because it moved when closing the door, it is no longer possible to open the lock from the outside, even having the key.
In this case, the use of a frictioned cylinder or one with an emergency function solves the problem and saves the cost and bother due to an outside intervention.
Hotels and communities
Frictioned cylinders or ones with an emergency function are also useful in hotels and communities in general, where it is necessary to have access to the various rooms, for emergency or service reasons, even if they are locked from the inside.
Instead of the knob
As we have seen, a frictioned cylinder, or one with an emergency function, may also be useful to avoid installing an internal knob, which is not always desirable from the point of view of security. With a cylinder of this type it is possible to leave a key inserted inside – only when you are at home – which performs the same functions as the knob, allowing the lock to be quickly opened and closed. The difference is that, when one leaves the house, the key is removed, thereby eliminating a convenient way out for a potential burglar who has entered the house through, for example, a window.
Cylinders with emergency functions and frictioned cylinders are special designs in the panorama of security products. Their strong point is not merely their effectiveness in preventing unauthorised access, but also in making access always possible… of course only to those in possession of the right key!