What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Generally speaking, combination screws are widely used in electrical, electric, mechanical, electronic, household appliances, furniture, ships and so on. But the above said that different combination screws have different functions. For example, Phillips pan head combination screws are generally used in small electronic products. Larger cross hexagon combination screws are used in larger electrical products, such as frequency converters, and some larger frequency converters use many cross hexagon combination screws. Hit the inverter case. To loosen the tightening effect. For example, two combination screws with flower teeth, which are used on the inverter, are used to break the paint, so that all the two combination screws on the surface of the casing are powered on. There is also a two-combination screw with a square pressure line, which itself is a two-combination screw with a pan head screw and a square pad. It is generally used on the surface of the terminal block. The function is for wiring and for crimping.
self-locking nut is a nut that can self-lock by friction. The general nut will loosen itself due to vibration and other reasons during use. In order to prevent this phenomenon, the self-locking nut was invented. The main functions of self-locking nuts are anti-loose and anti-vibration. For special occasions. Its working principle is generally self-locking by friction. The types of self-locking nuts classified by function include those with nylon rings, those with neck closures, and those with metal anti-loosening devices. They are all effective torque type lock nuts (see GB/T3098.9-2002 national standard).
When checking the finished blind rivet, check: the diameter of the rivet body, the length of the rivet body, the thickness of the rivet body cap, the diameter of the cap, the total length of the mandrel, the exposed size of the mandrel, the size of the nail cap, and the outer diameter after assembly can be considered. In the actual inspection, the weak links of the product can be measured, such as: tensile force, shear resistance, and core pull-out resistance. The key is to pay attention to the rivets, if the rivets are insufficient, whether they are riveted in place; or because the cap of the mandrel is too large, so that the mouth of the rivet body cannot be pulled down; and there are jump heads, that is, the mandrel is too low or broken. The size is too small etc. Length measurement of closed blind rivets
Now the screw itself is made of metal, so it is easy to rust, especially screws in harsh weather environments that are exposed to the air for a long time, such as air conditioners, wires, etc. In the existing technology, the shape of the screw has been fixed, and the structure of the screw itself is composed of a shaft with twill in the middle and a polygonal structure with stripes on the outside. OK, but because of the installation of some equipment, it needs to be exposed to the air for a long time. For example, the outdoor unit of the air conditioner must be installed in the outdoor area, and the outdoor can not be sheltered from wind and rain, so after long-term sun and rain, the screw The surface is easy to rust. If the rust is serious to a certain extent, the nut will be embroidered to death. Once the external machine needs to be disassembled one day, the embroidered screw will lose its use value and give workers to the workers. The disassembly and assembly of the screw has caused a lot of trouble, because the embroidered screw cannot be unscrewed directly. The only method used is to cut off the shaft in the middle of the screw with a hacksaw, or discard the entire screw structure. Since the shaft in the screw has been inserted into the middle of the wall, this waste is not good for both aesthetics and safety. To solve the rust problem of the screw, the existing technology is to improve the material of the screw, or to maintain it regularly, but this method itself is time-consuming and labor-intensive, and it is a waste of resources.
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