Non-standard screw news:
Screws are called industrial meters. Although they are small, they are definitely not small.
Especially high-tech objects such as aircrafts must not be ignored. Once loosened, the consequences will be disastrous! So how to prevent the bolt from loosening?
Bolt connections on airplanes generally have anti-loosening measures, such as fuses, split pins, fuses, and safety screws. The smaller pallet nut is self-locking through an elliptical hole. This hole is elliptical when it is not installed, or through a nut. The slot on the tail is used for clamping.
Fuse
Use thin metal wires to connect two or more fasteners together. If a component has a tendency to loosen, it will be pulled by the fuse and stop developing.
Material: Low carbon steel, stainless steel, brass, etc. Low carbon steel wire is commonly used. When knotting, you can choose single-strand or double-strand fuse wire type. Generally, the form of double-strand twisted into braid is the most widely used, as shown in the figure below.
Single-row fuses are usually used in small screw groups, which are closely spaced or difficult to reach, as shown in the figure.
Generally speaking, if multiple threaded fasteners are gathered together, it is better to use the form of mutual series insurance rather than each independent insurance. According to the specific situation, the number of fuse components for one-time cross-insulation can be determined.
Overhead
safety pin
Security screw
In addition, screw self-locking is the most commonly used anti-loosening measure. Thread self-locking is usually achieved through a special thread profile, and the pitch (tooth pitch) of the self-locking thread is small. Usually the performance of the self-locking force depends on the nut, unless the nut is particularly damaged, so the self-locking force failure can usually be solved by replacing the nut. How to prevent the screws from loosening during use?
The connection of ordinary screws and nuts is self-locking, and will not automatically loosen under the condition of static load and little change in working temperature. However, due to impact, vibration or variable load, and the operating temperature does not change much, this connection may loosen, affect work, or even cause an accident. In order to ensure the safety and reliability of the connection, effective anti-loosening measures must be taken for the connection of the screw and the nut.
1. Choose screws with appropriate specifications and sizes, larger or smaller sizes. They may be used reluctantly at the moment, but after a long period of time, they will inevitably become loose or locked.
2. Special engineering plastics are processed on the threads, which can make the screws produce strong friction torque and reaction force due to the extrusion of the engineering plastics during the tightening process, and produce absolute resistance to vibration, making ordinary screws permanent and powerful. The anti-loosening screw completely solves the problem of loosening of the connection between the screw and the screw.
3. Anti-loose and anti-loose methods to increase friction. This anti-loosening method is to prevent the tightened threads from losing pressure due to changes in external load, so there is always frictional resistance to prevent the connection from loosening. Anti-loosening methods to increase friction include the installation of spring washers and the use of double nuts.
4. Mechanical anti-loosening This anti-loosening method uses various stop devices to prevent the screw from rotating relative to the part to realize the anti-loosening. Mechanical anti-loose agents are more reliable and therefore more suitable. Common mechanical anti-loosening measures include split pins and slot nuts, non-return washers and disc nuts, stop washers and nuts, and Shenlian steel wire.
5. Non-detachable loosening method. Use tack welding and spot riveting to fix the nut on the bolt or the connected part, and the screw can be fixed on the connected part, so as to achieve the effect of anti-loosening.
