Service HotlineStandard screw is one of the fasteners commonly used for fastening and assembly. Standard screws and flat washers, grade A, and standard spring washers, are used in combination, and are widely used in the assembly of various products. For manufacturers who use combination screws in small and medium batches, the process of combining screws, spring washers and flat washers generally adopts the method of assembling screws by workers' bare hands. This method is tedious and repetitive, wastes human resources, is time-consuming and labor-intensive, and it is difficult to ensure the normal operation of the workshop. assembly progress. The screw assembly machines currently on the market can replace manual assembly screws, but this type of equipment has disadvantages such as bulky size, high cost, complex structure, inconvenient non-standard manufacturing and maintenance, high noise, and power consumption.
The classification of the second combination screw is divided according to the material of the screw wire and the hardness index of the screw wire. Generally, the two combination screws are divided into stainless steel and iron, and stainless steel is divided into stainless steel 201, stainless steel 304 and stainless steel 316. Iron is divided into three types: low carbon steel, medium carbon steel, and high carbon steel. Carbon steel combination screws refer to iron combination screws. Generally, iron combination screws are classified into grades 4.8, 8.8, 10.9, and 12.9. But in the market, the combination screws of grade 10.9 and grade 12.9 are rarely used, so we won't talk about it here. And the two combination screws on the market are more commonly used combination screws of grade 4.8 and 8.8. 4.8 grade combination screws are generally made of 1010A screw wire rods. After the screw wire rods are beaten into screws, they are combined with spring flat washers. After production, this 4.8 grade combination screw does not need to be hardened. Its hardness can reach 4.8. The 8.8 grade combination screw is generally made of 10B21 screw wire. After the screw wire is punched into a screw, it is equipped with a spring washer and a flat washer, and the three pieces can be combined and rubbed by an automatic spring-flat washer machine. Fasten the spring-flat washer combination on the screw, and the spring-flat washer will not fall off. After the combination screw is produced, it needs to be hardened to make the hardness reach 8.8. After the hardness reaches 8.8, we need to take it for electroplating. In order to prevent hydrogen embrittlement of the spring washer in the 8.8-level combination screw with added hardness, it is easy to break. In this way, it is necessary to carry out hydrogen removal treatment on the hardened combined screws, and the electroplating can only be done after the hydrogen removal.
Further, the pressure riveting portion and the pressure-bearing portion are both columnar structures, the outer diameter of the pressure-bearing portion is larger than the outer diameter of the pressure riveting portion, the pressure riveting portion is a stepped structure, and the diameter of the lower end of the pressure riveting portion is smaller than that of the pressure riveting portion. The diameter of the upper end of the rivet part.
In steelmaking plants, the wheels of metallurgical casting crane trolleys used for hanging liquid metal are connected with cardan shafts through flanges. Usually, a keyway is set in the radial direction of the connecting flange, and the keyway is a through groove. The B-type flat key is set in the keyway to transmit torque. During the frequent forward and reverse motion of the wheel, the flange connection bolts are easily loosened. Since the keyway is a through groove, the B-type flat key is easily caused when the flange connection bolts are loosened. It falls off from the keyway of the connecting flange and cannot transmit the torque, which seriously affects the working efficiency of the locomotive. In addition, because the B-type flat key falls off and cannot transmit the torque, the locomotive can only rely on the connecting bolt to transmit the torque when it continues to work. Poor, it is easy to damage and scrap the connecting bolts, and then damage the connecting flanges, requiring frequent replacement and maintenance, high cost, and difficult maintenance.
However, although the existing screw can meet the function of connecting and tightening objects, its structure includes a head and a threaded rod connected with the head. Since it only has one threaded rod, it does not have a two-way connection function and cannot be satisfied with the Some special use requirements bring inconvenience to use.
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