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.
For common screw belts, please refer to the Central Taiwan Announcement No. 327449 on February 21, 1998, Screw Belts (2), which includes a main body with multiple grooves on the side of the main body for the purpose of locking screw tools to drive the belt. A toggler; and a plurality of nail grooves are arranged on the nail belt so that the screw planting is arranged in an arrangement, and the nail grooves are all provided with through holes, and the through holes extend downward with a ring to form a support portion for the screws; and the It is surrounded and provided with a plurality of cutting grooves, which is beneficial for the screw to be rotated through the nail groove; and it is characterized in that the nail groove is located on the inner wall surface of the surrounding and is provided with a plurality of lobes, and these lobes are implanted in the screw. In the nail groove, the leaflet supports the screw, so that the screws with different outer diameters are fully supported and positioned by the leaflet; and/or the upper part of the leaflet is inclined or curved, so that a depression is formed above the ring to support the screw The arc surface or tapered surface of the neck can make the screw more stable to be supported.
The main purpose of the embedded nut is to replace the direct opening of screw holes on the injection molded parts, so as to improve the strength of the screw holes of the injection molded parts. Referring to FIG. 1 , in order to lock the workpiece 3 ′ on the injection molded part 2 ′, the screw 5 ′ passes through the through hole on the workpiece 3 ′ and is screwed into the screw hole of the embedded nut 1 ′ to fix the workpiece 3 ′. The embedding between the embedded nut 1' and the injection-molded part 2' generally includes two ways. One is to heat the embedded nut 1' and then insert it into the injection-molded part 2' by hot pressing; the other is to insert the embedded nut into the injection-molded part 2'. 1' and the injection part 2' are integrally injection-molded. In order to ensure the bonding strength between the inner nut 1' and the injection molded part 2', knurling is provided on the outer peripheral surface of the inner nut 1'.
With the mass production of large-scale equipment, standardization, and the concept of lean production, it has become more and more important to improve the efficiency of the assembly stage. Nowadays, when assembling small equipment, power tools and automatic bolt supply devices are basically popular, but only for M3 and smaller However, large equipment is often fastened with M8 or larger diameter bolts, and it is still in the process of combining manual and air tools. Among them, the pre-installation of the flat and spring washers on the bolts is completely manual operation. When the bolts need to be tightened in large quantities, the shortcomings of low efficiency are particularly obvious, and the flat and spring washers are easy to be scattered when manually assembled, and there are mixed installations of different specifications. Problems such as less installation and missing installation will affect the processing quality.
There are many names for bolts, and everyone may have different names. Some people call them screws, some people call them bolts, and some people call them fasteners. Although there are so many names, they all mean the same thing, they are all bolts. A bolt is a generic term for a fastener. A bolt is a tool that uses the physical and mathematical principles of the oblique circular rotation and friction of an object to fasten the parts of the object step by step. [1] Bolts are indispensable in daily life and industrial production. Bolts are also known as the rice of industry. It can be seen that the bolts are widely used. The application scope of bolts includes: electronic products, mechanical products, digital products, electrical equipment, electromechanical products. Bolts are also used in ships, vehicles, hydraulic engineering, and even chemical experiments. Anyway, bolts are used in many places. Especially the precision bolts used in digital products. Miniature bolts for DVD, cameras, glasses, clocks, electronics, etc.; general bolts for televisions, electrical products, musical instruments, furniture, etc.; large bolts and nuts are used for engineering, construction, and bridges; transportation equipment, aircraft, trams, automobiles etc. are used together with large and small bolts. Bolts have important tasks in industry. As long as there is industry on the earth, the function of bolts will always be important.
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