Cylinder locks, or as they are often called “English”, got their name because their design is based on secret cylinder mechanisms. Cylinder mechanisms can be in the form of a cylinder, a circle, “droplets”, etc. The heart of such mechanisms is a set of spring-loaded pins, balls, plates of various sizes.
Cylinder design (IKON):
1 – cylinder body;
2 – cylinder core;
3 – key channel;
4 – pin of the cylinder mechanism;
5 – pin spring;
6 – cam of the cylinder mechanism;
7 – key
Cylinder locks, most often, are flat keys, along the edges of which, on one or both sides, there are cutouts (teeth), or point dents. Their number is equal to the number of locking pins in the cylinder mechanism, and the larger the number of pins, the higher the security of the lock. It is not recommended to use locks with less than five pins. In order to increase secrecy, leading companies produce cylinders for which two-, three- and four-row keys have been developed. The highest security is achieved in key cylinders with side perforations.
CISA cylinder with perforated key
The most vulnerable point of cylinder locks is the cylinder itself, the mechanism of which can be drilled, broken off or knocked out. To protect against drilling, reputable manufacturers install special, hardened pins or balls inside the cylinder to prevent the drill from penetrating, and the cylinder itself is protected with a hardened washer. To protect against breaking or knocking down the cylinders, a hardened steel safety pad or shield is installed, while the part of the cylinder protruding beyond the lining (shield) should not be more than 2 mm. Cylinders of a special shape (paracentric profile) and special steel clamps are also used to increase the resistance of the cylinder to its extraction.
As a rule, cylinder locks have increased secrecy, but low security properties..
A foreign object trapped in the keyhole of the cylinder is almost impossible to remove. This entails the subsequent replacement of the cylinder mechanism.
Cylinder with four rows of pins, with two-sided drill and pull-out protection, with locking device (BKS).
Conventional cylinder locks cannot be recoded, if the key is lost, the cylinder must be changed. To eliminate this drawback, on the basis of cylinder locks, a “master key” system was developed, which will be discussed below..
Effective security is known to require tight control over keys. On the one hand, the complex production of key copies causes inconvenience to the user, and on the other hand, if it is not difficult to order a key, then a criminal can also do it. Therefore, leading manufacturers usually offer several forms of customer service. For example, ASSA (Sweden) offers three types of work with blanks: absolute control (a pre-coded blank can only be ordered at the factory), patented control (additional keys can be ordered using a special card in dealerships), limited control (spare keys can be ordered by the owner of the key , the workpieces are not patented or protected). Other major lock manufacturers have adopted similar customer service schemes.
Various types of cylinders:
A – unilateral (CISA);
B – one-sided with a handle (KFV);
B – double-sided (CEZ);
Г – double-sided with a handle (CEZ);
D – double-sided with adjustable door closer (ABLOY);
E – double-sided, making it possible to open the cylinder even with the key inserted from the other side (IKON)
All cylinders can be divided into the following types: one-sided, two-sided, and also one-sided with a handle and two-sided with a handle. As a rule, double-sided cylinders cannot be opened if a key is inserted on the other side. However, in the production program of leading manufacturers there are cylinders that can be opened even with the key inserted from the other side..
As a rule, the lengths of the cylinders are in the range from 30 to 60 mm, which makes it possible to install them in door leaves of different widths. If necessary, cylinders can be of different lengths, both shorter and longer.
There are also cylinder locks, with the so-called cross-shaped key. In this case, the key is made in the form of a rod with cutting of secrets in three or four directions, which in cross-section resembles a “cross”. The mechanism itself is very small, does not protrude beyond the lock body, the pins are small and are located in a circle in different directions.
In order for cylinder locks to serve for a long time, the following recommendations must be observed: