Improvement of Self-Locking Structure for Bolts Used in Large Industrial Fans The bolts used in large industrial fans are self-locked by relying on the frictional force between the support surfaces of the nut and bolt head and the connected component support surface. However, when the fan encounters impact, vibration, or variable load, there is still a risk of the bolt becoming loose or even detached. Therefore, to address this risk, some industrial fan manufacturers have made improvements to ensure the stability of the self-locking structure of the bolts.
Firstly, this type of bolt is the same as ordinary ones, but a slightly larger spring pin is fitted onto the bolt. One end of the spring is fixed to the unthreaded end of the bolt, and the other end is made flat and obliquely downward, in the same direction as the direction the nut is tightened onto the bolt. The nut is also an ordinary one, except that one end is made into a sawtooth-shaped ring, with the sawtooth direction opposite to the direction the nut is tightened onto the bolt. This process is not complicated and has a relatively low cost. However, let's simulate the working process to see how effective it is.
Using this kind of bolt to connect the components of the two large industrial fans, the components are in constant vibration in the working environment. Firstly, tighten the nut with a wrench. As it is continuously pushed forward, the spring is compressed and the flat contact surface of the spring pin continuously slides over the sawtooth of the nut. At this time, when the nut is turned counterclockwise, the tangential force of the spring will produce some resistance. This achieves the goal of self-locking. Even in a vibrating environment, the nut tends to loosen, but the head of the spring pin locks the nut, preventing it from rotating in the opposite direction. Moreover, due to the vibration, the tangential force of the spring will tighten the connected components more tightly, which is a good anti-loosening method. If the connected component is relatively thick, the spring will be longer. This wastes materials and does not achieve good results. Therefore, there is an improvement here. That is, the end of the spring should not be fixed to the head of the bolt, but to a certain part in the middle of the bolt so that the tangential force (circumferential force) of the spring can be fully utilized. This type of bolt uses a physical method for self-locking, which is simple, firm, and does not change the bolt and nut structure on the whole, enabling cost savings based on the original design. For structures such as large industrial fans that are not frequently or not disassembled, this improvement method can effectively meet the anti-loosening requirement. Of course, this approach is also an upgraded improvement made for the structure and force bearing of the manufacturer's fan. Different manufacturers can transform the bolts according to their product characteristics to achieve the safety goal of preventing loosening and falling.