What are Fasteners?
Fasteners are a type of mechanical parts used for fastening connections and are used in a wide range of applications. Fasteners are characterized by a wide variety of specifications and different performance applications, and a high degree of standardization, serialization and generalization. Therefore, there are also people who have national (industry) standards for a class of fasteners called standard fasteners, simply called standard parts.
As the specifications, dimensions, tolerances, weight, performance, surface conditions, marking methods, acceptance inspection, marking and packaging of each specific fastener product are different, there are several national (industry) standards, such as British, German and American standards.
Fasteners are the most widely used mechanical foundation components. With China’s accession to the WTO in 2001 and its entry into the ranks of major international trading countries. Chinese fastener products are exported to a large number of countries around the world. Fasteners, as one of China’s large import and export products, to achieve international convergence, to promote China’s fastener enterprises to the world, promote fastener enterprises to participate in international cooperation and competition, are of great significance.
A fastener is a general term for a type of mechanical part that is used when two or more parts (or components) are fastened together into a single unit. Also known as standard parts in the market.
What are the classifications of fasteners?
It typically includes the following 12 categories of parts.
1. Bolts: A class of fasteners consisting of a head and a screw (cylindrical body with a male thread), in conjunction with a nut, for connecting two parts with through holes. This form of connection is called a bolted connection. If the nut is screwed down from the bolt, the two parts can be separated, so the bolt connection is a removable connection.
2. Stud: A fastener without a head, but with an external thread on both ends. When connected, one end of it must be screwed into the part with the female threaded hole and the other end through the part with the through-hole, then the nut must be screwed on, even if the two parts are tightly connected as one. This form of connection is called a stud connection and is also a removable connection. It is mainly used for connecting parts with large thickness, requiring compact structure, or where bolt connections are not suitable due to frequent disassembly.
3. Screw: A fastener consisting of two parts, the head and the screw, which may be divided into three categories by use: machine screws, set screws and special purpose screws. Machine screws are mainly used for a part with a tightened threaded hole, connected to a part with a through-hole, without the need for a nut fit (this connection is called a screw connection and is a removable connection; it can also be used with a nut for a tightened connection between two parts with a through-hole). Set screws are mainly used to fix the relative position between the two parts. Special purpose screws are used for special connections, such as lifting ring screws, for lifting parts.
4. Nuts: with a female threaded hole, the shape is generally shown as a flat hexagonal column, but also flat square column or flat cylindrical, with bolts, studs or machine screws, used to tighten the connection between two parts, so that it becomes a whole.
5. Self-tapping screw: Similar to machine screws, except that the threads on the screw are dedicated threads for self-tapping screws. It is used to fasten two thin metal components to form a single unit, and small holes need to be drilled in the components beforehand, due to the high hardness of this screw, can be screwed directly into the hole of the components, so that the components form a responsive female thread. This form of connection is also a removable connection.
6. Wood screws: Similar to machine screws, except that the threads on the screw are specifically ribbed for wood screws, which can be screwed directly into a wood member (or part) for fastening a metal (or non-metal) part with a through-hole to a wood member. This connection is also a removable connection.
7. Washers: A type of fastener with a flat circular shape. Placed between the bolt, screw or nut support surface and connected parts surface, plays a role in increasing the contact surface area of the connected parts, reduce the pressure per unit area and protect the surface of the connected parts from being damaged; another type of elastic washer, can also play a role in preventing the nut back loose.
8. Retaining ring: A ring fitted in the shaft groove or bore of a machine or piece of equipment, which acts to prevent the parts on the shaft or bore from moving left or right.
9. Pins: Mainly used for positioning parts, some are also used for connecting parts, fixing parts, transferring power or locking other fasteners.
10. Rivet: A fastener consisting of two parts, the head and the nail bar, used to fasten two parts (or components) with through-hole connections into a single unit. This form of connection is called a rivet connection, or rivet joint for short. The genus is connected to the non-removable. If two parts that are joined together are to be separated, the rivets on the parts must be broken.
11. Assemblies and joints: Assemblies are a class of fasteners supplied in combination, such as a combination of a machine screw (or bolt, self-supplied screw) and a flat washer (or spring washer, lock washer); joints are a class of fasteners supplied in combination with a specialized bolt, nut and washer, such as a high-strength large hex head bolt joints for steel construction.
12. Welded nail: An exotic fastener consisting of light energy and a nail head (or no nail head), which is fixed to one part (or component) by means of welding, so that it can be connected to other parts.
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