Door locks are installed to ensure safety. Do you know the mutual opening rate of locks?

The door lock is used in every family. Do you know that the anti-theft door lock core has "mutual opening rate"? That is, the probability that different anti-theft doors can be opened to each other. The lower the mutual opening rate, the better the safety of the lock. During the test, take the specified sampling number and fully open the test number. According to the corresponding national standards, three of the 10000 locks are the same; The mutual opening rate of class B lock is ≤ 0.01%; The mutual opening rate of class C lock is low, about ≤ 0.0004%, that is, four of one million locks are the same.

How to determine the mutual opening rate of locks?

Let's take a look at the structure of ordinary bullet lock:

There are two main factors affecting the mutual opening rate: one is the tooth flower on the key, and the other is the bullet of the lock cylinder. Generally speaking, there is a combination of tens of thousands of lock shapes and flower shapes for each manufacturer. In theory, that's enough. However, if the enterprise is mismanaged and different batches of locks are mixed together, the lock cylinders with the same tooth arrangement may be placed together or sent to the same place. This will lead to news reports that a key can open several doors. For marble, according to national standards, the thickness of marble shall be at least greater than 0.5mm. However, due to careless processing or cutting corners, the marble quality of some enterprises is unqualified and inaccurate, which can not well reflect the level difference of lock heads, resulting in high mutual opening rate. The simpler and cheaper the lock cylinder is, the more complex the arrangement order of the springs in the simple lock is, the combination mode is also limited, and the higher the repetition rate is.


Select high-grade lock cylinder and observe the number and shape of key teeth. The more the number and shape of complex keys, the lower the mutual opening rate of the corresponding lock, while the flat, smooth and shallow tooth keys will increase the mutual opening rate.