What are the fastener parts?
2019-07-25
Fasteners are a kind of mechanical parts used for fastening connection and widely used. Fasteners are widely used in various industries, including energy, electronics, electrical appliances, machinery, chemical industry, metallurgy, dies, hydraulic and other industries. Various kinds of fasteners can be seen in machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, chemical industry, instruments and supplies. It is the most widely used mechanical foundation. It is characterized by a wide variety of specifications, different performance and uses, and a high degree of standardization, serialization and generalization. Therefore, some people refer to a kind of fasteners in the existing national standards as standard fasteners, or referred to as standard fasteners for short.
It usually includes the following parts:
1. Bolts: A class of fasteners consisting of a head and a screw (a cylinder with external threads) that need to be matched with nuts to fasten and connect two parts with through holes. This connection form is called bolt connection. If the nut is screwed off from the bolt, the two parts can be separated, so the bolt connection belongs to the removable connection.
2. Screw: No head, only a kind of fastener with threads at both ends. When connecting, one end must be screwed into a part with an internal thread hole, the other end must pass through the part with a through hole, and then the nut is screwed up, even if the two parts are tightly connected into a whole. This form of connection is called stud connection and also belongs to removable connection. It is mainly used in situations where one of the connected parts is thicker, requires compact structure, or is not suitable for bolted connection because of frequent disassembly.
3. Screw: It is also a kind of fastener consisting of head and screw. It can be divided into three categories according to its use: machine screw, fastening screw and special purpose screw. Machine screw is mainly used for a part with fixed threaded holes, and a part with through holes between the fastening connection, do not need nut coordination (this connection form is called screw connection, also belongs to the removable connection; can also be matched with nuts, for two parts with through holes between the fastening connection). Fixing screw is mainly used to fix the relative position between two parts. Special purpose screw such as ring screw for lifting parts.
4. Nuts: with internal threaded holes, the shape is generally flat hexagonal cylinder, but also flat square cylinder or flat cylinder, with bolts, studs or machine screw, used to fasten the connection of two parts, making it a whole.
5. Self-tapping screw: similar to machine screw, but the thread on the screw is special thread for self-tapping screw. It is used to fasten two thin metal components and make them a whole. Small holes need to be made in advance. Because of the high hardness of the screw, it can be directly screwed into the holes of the components to form internal threads in response.
6. Wood screw: It is similar to machine screw, but the thread on the screw is a special wood screw thread, which can be directly screwed into the wooden component (or part) for fastening a metal (or non-metal) part with a through hole to a wooden component. The connection is also removable.
7. Gasket: A kind of fastener with flat circular shape. Placing between the support surface of bolts, bolts or nuts and the surface of connecting parts plays a role in increasing the contact surface area of connecting parts, reducing unit area pressure and protecting the surface of connecting parts from being damaged. Another kind of elastic washer can also play a role in preventing the loosening of nuts.
