Class A lock: At present, the A-level anti-theft lock key on the market mainly has a word key and a cross key. The internal structure of the A-class lock cylinder is very simple, limited to the change of the marble, and the marble groove is small and shallow. The anti-technical opening time is extremely high within 1 minute. The marble structure is a single row of marbles or a cross lock.

Class B lock: Class B lock key is a flat key, with double row of marble slots. The difference with A lock is that there is a row of curved and irregular lines on the key surface. The main types of lock cylinders are 3 types, computer double-row lock core, double-row crescent lock core, double-sided vane lock core. The anti-technical opening time is 5 minutes, and the mutual opening rate is high. With a strong twist tool, the lock cylinder can be opened in 1 minute.

Class C lock (Super B grade): The key shape is the single-sided blade inner milling groove, the outer milling slot key or the double row + blade form, the lock core type is the side column lock core, which can not be opened by the Ministry of Public Security for 270 minutes. The regional mutual opening rate is zero (one in six million). The structure of the marble is locked by the double row of blades and the V-shaped side column; if the lock cylinder is opened by a strong twisting tool, the internal core of the lock cylinder is broken, and the self-explosion is locked, resulting in failure to open.

First, the A-level anti-theft lock

Only the marble slot is a Class A anti-theft lock on the spoon, and the number one key and the cross key are the most common. Although the texture on the key does not look like a dot, the corresponding lock cylinder is a marble structure. The internal structure of the lock cylinder is very simple, limited to the change of the marble, and the marble groove is small and shallow.

Second, the B-class anti-theft lock

The key has both a marble slot and a milling slot. It is a Class B lock. This lock is usually equipped with a flat key. It is double-sided and double-row. The key mainly includes a single-row anti-pull key and a single-row crescent key. The internal structure of the lock cylinder is complex with respect to the A-level lock, and the anti-theft function is also safer than the A-level lock.

Third, (C-level lock) super B-class anti-theft lock

The Super B-class lock is currently a safer level. From the key, it is usually a double-sided double-row bullet slot with a blade or curve next to it. The work of the lock cylinder is rigorous and complicated. The monitoring of the relevant departments is based on the technical opening of more than 270 minutes, which can be used with confidence.

Fourth, anti-theft door lock inspection

1. Check the safety level of the lock: When purchasing, the merchant must be required to present the safety level certificate of the lock used by the security door to see if it is a special anti-theft lock that has passed the inspection by the public security department, and select the safety door according to the lock level.

2. Check the security door lock: the steel plate with a thickness of 3mm or more should be protected at the lock.

3. Check the length of the main door lock of the anti-theft door: the effective length of the main lock tongue of the anti-theft door should be no less than 16mm, and there should be a bolt stop device. If not, it will not be qualified.