There are three basic types of anti-loosening methods for the connection of basic threaded fasteners:
a. Non-detachable locking
This is a loosening method that changes the detachable screw connection into a non-removable screw connection by means of welding, bonding or riveting, and is a very reliable traditional method of preventing loosening. The disadvantage is that threaded fasteners cannot be reused. And the operation is troublesome. It is often used in certain important situations where it is required to prevent looseness and reliability without requiring disassembly.
b. Loosening of mechanical fasteners
The mechanical fastener is used to fix and pinch between the screw and the connected part or between the screw and the screw to stop the looseness. The advantage of this method is that the anti-looseness is reliable, and its anti-looseness reliability generally depends on the static strength or fatigue strength of the mechanical fastener (or the fastener itself, such as a slotted nut). Its disadvantage is that it increases the weight of the fastening connection, it is troublesome to manufacture and install, and it cannot be installed mechanically, so the cost is high. Due to its high reliability against loosening, some important parts in mechanical products and aerospace products are still widely used.
c. Anti-looseness to increase friction
The purpose of preventing loosening is achieved by increasing the friction between the threads or the heads of the bolts (screws) and the nut, or by increasing the friction between both. This kind of anti-loosening method is less reliable than the above type a or b methods, but its greatest advantage is that it is not limited by the use of space, it can be repeatedly assembled and disassembled, it can be maneuvered, and some of them Fasteners (such as nylon ring locknuts, all-metal locknuts) have achieved a very high level of reliability against loosening. Therefore, this kind of anti-loose method is most widely used in the mechanical manufacturing sector and aerospace field.