In our life, there is a general name for a hardware product that can be regarded as a standard part. We collectively call them fasteners, and fasteners are widely used as a mechanical component in the discipline inspection commission in fastening applications. Widely used in energy, electronics, electrical appliances, machinery, chemical industry, metallurgy, molds, hydraulics and other industries, in various machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, chemicals, instruments and supplies As above, you can see all kinds of fasteners, which are the most widely used mechanical basic parts. It is characterized by a large variety of specifications, different performance uses, and the degree of standardization, serialization, and generalization is extremely high. Therefore, some types of fasteners that already have national standards are called standard fasteners, or simply referred to as standard parts. This is the standard in the solid parts industry.

Fasteners usually contain 12 kinds of parts

1. Bolt: a type of fastener consisting of a head and a screw (a cylinder with external threads), which need to cooperate with a nut to fasten two parts with through holes. This type of connection is called a bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

 

2. Studs: There is no head, only a type of fastener with external threads at both ends. When connecting, one end of it must be screwed into a part with an internally threaded hole, the other end is passed through a part with a through hole, and then the nut is screwed on, even if the two parts are firmly connected into a whole. This type of connection is called a stud connection and is also a detachable connection. It is mainly used in the case where one of the connected parts has a large thickness, requires a compact structure, or is not suitable for bolt connection due to frequent disassembly.

 

3. Screw: It is also a type of fastener consisting of the head and the screw. It can be divided into three categories according to its purpose: machine screws, set screws and special-purpose screws. Machine screws are mainly used for a tight connection between a part with a threaded hole and a part with a through hole, without the need for a nut (this type of connection is called a screw connection and is also a detachable connection; it can also be Cooperate with the nut for fastening connection between two parts with through holes.) Set screws are mainly used to fix the relative position between the two parts. Special-purpose screws such as eyebolts are used for lifting parts.

 

4.Nuts: with internal threaded holes, generally in the shape of a flat hexagonal cylinder, and also a flat square cylinder or a flat cylinder, with bolts, studs or machine screws, used to fasten and connect two parts, so that It becomes a whole.

 

5. Self-tapping screws: Similar to machine screws, but the threads on the screw are special threads for self-tapping screws. It is used to fasten two thin metal members to make it a whole.A small hole must be made on the member in advance. Due to the high hardness of this screw, it can be screwed directly into the hole of the member to make the member Form a responsive internal thread.

 

6.Wood screws: similar to machine screws, but the screw on the screw is a special wood screw thread, which can be directly screwed into the wooden member (or part), used to put a metal (or non-metal) with a through hole The parts are fastened to a wooden member. This connection is also a detachable connection.

 

7. Washer: a type of fastener with a flat circular ring shape. It is placed between the support surface of the bolt, screw or nut and the surface of the connected part, which plays the role of increasing the contact surface area of the connected part, reducing the unit area pressure and protecting the surface of the connected part from being damaged; It can also play a role in preventing the nut from loosening.