First look at the type of lock cylinder In the right cylinder lock of the security should be the maximum weight, wherein the door look orifices keyhole shape, the order of security level of force "a" shape, "ten" shaped, circular, crescent-shaped (in key bits on both sides of the teeth) , ring (circular, ring-shaped keyhole can not have side slots, especially the two-sided slot with a 180-degree angle, the side slot can be regarded as a figure, in fact, these lock core anti-theft, because of the tool The progress is only a difference in degree, not a qualitative difference.) The idling lock (the keyhole is commonly seen as a "ten" shape, crescent shape, etc.), the blade lock (which needs to be carefully designed for the shape and spatial position of the blade). Locks for bicycle theft prevention in colleges and universities, the most cost-effective lock cylinder is “idle lock”, which is characterized in that the general key or other objects protrude into the lock cylinder, and even other lock keys of the same model can only rotate freely. The lock cylinder does not open the lock. If you put some brains on the position of the lock cylinder and design some anti-theft obstacles, the idle lock cylinder still has a high degree of safety.
Secondly, look at the materials used in the locks.
There is a famous short board theory of wooden barrels, and the truth can be established in the anti-theft of locks.
1The material is insufficient, the line is not thick, the manufacturer is saving the material, and the cost reduction is also a very real problem. The design of the lock core is more reasonable, and the processing is refined. If the material used for the lock body is insufficient, there will be no anti-theft. Functional, the thief is a bad person, the law does not stipulate that the bad guys are stupid, on the contrary they are very embarrassing. The lock core is done, it is difficult to break, they will attack the body, if it is too thin, then the forceps will wait. 2 The overall design of the lock is unreasonable. There are no weak links. For example, some “U”-shaped locks, the lock bow is very thick, and the lock design is reasonable. However, the combination of the lock bow and the lock body is very thin and obviously short. The board effect, for example, the wire lock, is not considered for the shear resistance of the steel wire. If the condition is special, the lock needs to have a certain length, and a good Chain Lock of the material can be selected. 3 The material is used well, the lock body is made of zinc alloy, the strength is low and fragile, the aluminum or aluminum alloy is more unstable, the ductile iron material has a certain strength, I think it should be made of steel, and it is hardened by heat treatment. Anti-mite, anti-pliers.
Look again at the manufacturing precision of the lock cylinder, marbles and keys.
For example, how many tooth positions, the highest to the lowest difference of the ball stroke of each tooth position, can be effectively divided into a number of steps, which determines the mutual opening rate of the lock. For example, the ball stroke corresponding to each tooth position has 3 height precisions, and there are four tooth positions on the key. The key corresponding to this type of lock has only 81 combinations. The mutual opening rate is very amazing, there will be no safety. For example, the ball stroke corresponding to each tooth position has 4 height precisions, and there are 7 tooth positions on the key. The key corresponding to this type of lock has 15,526 combinations in theory, and the mutual opening rate is much lower. It should also be mentioned that there is a certain degree of mutual opening between the keys with small differences in adjacent combinations, which makes the mutual opening rate calculated by the combination of the purely theoretical ratios worse. For those models that are shoddy, the lock cylinder may have only a few hundred key codes, that is, only a few hundred keys; the design of the lock core model can have hundreds of thousands of keys.
The author currently believes that for the difference between the internal and external public security environment of colleges and universities, the use of colleges and universities is more cost-effective, and the medium-sized anti-theft idling lock of Dr. Lock can be considered as one of them, about 65 yuan.
