Bicycle locks recommended by some local small public security bureaus are still low-grade locks, and the profits of merchants are half and half.
Therefore, there is no access system for the sale and production of low-grade bicycle locks, which endangers public interests.
Therefore, this is the work of the public security department, the industrial and commercial bureau and the quality supervision bureau, and should be led by the government.
A broken lock can only be opened with an electric grinder. You can choose an unconventional key to reduce the possibility of theft, or you can choose a lock with lower security to lock the bicycle with a fixed object.
The former has no jobs, but the latter monopolizes resources and power, which is endangering national security!
The biggest obstacle is that what can be done is not allowed to be done, and what cannot be done is in the hands of mediocrity. It's not a question of treatment, but there is no post at all, no access to the laboratory and no use of idle ordinary instruments. If your question recurs in Zhou Enlai, it will be easy to solve. And the locks that meet your requirements have been on the market for a long time, from molds to production lines. There is no need for scientific research, re-development and re-investment. There is nothing in the hardware market and bicycle retail market, and citizens have no ability to judge and investigate.
Some simple suggestions:
Don't install the lock firmly on the bicycle body, which will facilitate the thief to exert his destructive power.
The lock hook is larger than 15mm in diameter and is generally made of low carbon steel. The wholesale price below 25 yuan is not carburized, and the hardness is not enough, so it can be cut. Carburizing is called "hardening type" in the commodity. Another way to judge whether carburizing is completed is to use a manual saw blade or a steel saw blade with a length of 300mm, a thickness of 0.64mm and a width of 12 or 13mm. The carburized lock hook can't be sawed in, and the saw blade slides straight on the lock hook. Accordingly, the effective diameter of the chain is generally not carburized, and stainless steel can be thinner, because stainless steel is soft and tough and sticky when cutting; Generally, metal pipes with a diameter greater than 20 mm and a wall thickness greater than 1.5mm will be cut continuously. At least, the opening of scissors is not that big. Even if the opening is large, there is not much shear force applied, because the levers are inclined to each other and it will slide. You can use the tap water pipe of the faucet.
Open the hook and turn the key, you can see the lock tongue, which is the part of the lock body that blocks the hook, and the steel ball with the diameter of 10 mm is reliable; Generally, the lock tongue is stamped with low carbon steel, with a thickness of less than 2 mm and a width of less than 15 mm, and the lock tongue protruding from the copper lock core is not resistant to impact.
Pick the lock body with a magnet, and the lock body is made of iron. The thickness of the lock body tube should be greater than 2.0 mm, otherwise the pin will be weak. Those locks with embossed fonts are usually die-cast with zinc alloy, which is too fragile.
The whole copper lock body is basically not produced now, and the charge is 80 yuan/handle to 150 yuan/handle, which is quite heavy.
In reality, a better lock body is made of a whole piece of iron, and a cavity is dug in it with a milling machine or lathe, rather than a cheap product cut with a square tube or a round tube.
Originally, both the cross key and the crescent key can be used, but in fact, many locks have a small number of marbles, a small stroke range (large height difference between teeth), and even do not need spring reset. The bronze medal and material of copper lock core are poor, and the diameter of marble is small, the number of marble is small, and the height of marble is low and unreliable.
You can usually find a key with teeth on both sides, a square rod and a key with notches milled on both sides.
The key of sleeve shape also depends on the number of marbles, the height of marbles and the firmness of pins.
The best locks are original, which can improve the industrial base level of China. It is suggested to implement the national system, national competitions and competitions. I have seen some bicycle locks made by cyclists. This truly reflects the basic industrial level of the people. What is really confidential is the lock with high precision and abnormal structure made by ourselves, which is not in circulation in the market.
For example, the lock of the Beijing collider can only be opened by two people using mechanical keys at the same time, and the cockpit lock and prison lock of military aircraft are customized; The communication security machines of military, diplomatic and government departments in various countries are all designed and produced by themselves. As a sovereign country, this kind of equipment is not imported for key sectors.
I have published a paper on curbing crime in English at international academic conferences, which belongs to daily life knowledge.
Nowadays, hydraulic tongs are popular, and the common hook diameter is15 mm. When the blade of the hydraulic clamp is pressed into the hook less than half, the hook will break! ! ! Maximum opening of domestic hydraulic tongs 12 mm 360 yuan; A The maximum opening in 390 yuan is 16mm, and some openings are 14mm. Generally, the retail price of A with a maximum opening of 20mm can be one in 350 yuan, and that of imported manual hydraulic pressure is 80mm. Use hydraulic tongs in remote and dark places; Use a hard key to unscrew it in a crowded place.
The diameter of the self-made lock hook is greater than 20mm, which can be a pipe hook, or a good lock can be used. One or more steel bars are welded on the original lock hook, or the faucet iron pipe is put on. Nowadays, the blades of portable hydraulic tongs can't be opened that big. Note that the lock body and the lock hook are hinged or hinged, or the lock hook and the lock body can be separated, and there should be a hanging shielding widening reinforcement at their joint to prevent thieves from getting pliers from here. For the lock body of zinc alloy, the lock body of zinc alloy has been welded with an iron shell, the lock hook has been welded with three rebar strips with a diameter greater than 1.2mm for use in the construction site, and the keyhole has been welded with an elbow with a thickness greater than1.5mm. To unlock the lock with a key, it is necessary to rotate it from the side and extend it into the keyhole to prevent the straight rod from forcibly invading the key illegally. After being locked by a fixed object, people who stop at various occasions every day and deliver goods everywhere have experienced several years of actual combat. ! ! ! !