A Secure Bolt Locking Method for Agricultural Drones

Feeding China’s huge population is a massive challenge, and its agricultural sector is progressively modernizing to make it more effective. Unmanned Aerial Vehicles (UAVs) are one new technology that plays a critical role.

China is the world’s largest agricultural producing country. This should come as no surprise given that it is also the most populous country on earth, with some 1.413 billion people, slightly more than the entire African continent. 

Feeding that enormous population is a massive challenge. However, if you can grow it and eat it, China is almost certainly the world-leading producer. This goes for rice and most other grains, vegetables, and fruits. 

The Food and Agricultural Organization of the United Nations (FAO) writes that, “China has succeeded in producing one-fourth of the world’s grain and feeding one-fifth of the world’s population with less than 10 percent of world arable land, which is a great achievement in pursuit of food and nutrition security not only in China but also in the world.” 

 

Technology makes farming more effective 

The Chinese government has made agricultural development and modernization a top priority, aiming to make production more effective and optimize the entire agricultural value chain. Going from decentralized small-scale land operations to large-scale models that use efficient agricultural methods is essential. 

It is also critical to speed up breakthroughs in, and adoption of, agricultural technologies. As a result, state-of-the-art equipment is increasingly used, such as UAVs (Unmanned Aerial Vehicles). 

After ten years of rapid development; agriculture, forestry, and plant protection UAVs made up some 42 percent of the country’s civil UAV market in 2020. 

 

UAVs help ensure high yields 

UAVs bring many benefits to agriculture, such as efficiently monitoring and analyzing fields and crops. To ensure high yields, they also simplify crop spraying/dusting with fertilizers, pesticides, and plant nutrients. Previously, this was generally done by farmers walking or vehicles driving through the fields or using agricultural airplanes. 

With UAVs, farmers are not dependent on suppliers and can save time and money. They can operate the UAV themselves, or it can be done autonomously. One source states that a 15-minute UAV observation flight can sometimes accomplish as much as three or four hours of manual observation. 

Add to that safety. Flying a crop-spraying airplane is not for the faint-hearted or inattentive. For example, keeping track of high-voltage electric lines takes alertness, and serious accidents are not uncommon. Using UAVs, this type of incident decreases significantly. 

 

A very competitive UAV range 

Agricultural UAVs used for large-scale crop spraying can typically lift a heavy load of liquids. The Chinese manufacturer Shangliang Zhongyi (SLZY) Hi-tech Co., Ltd. offers the Houji range of high-precision plant protection UAVs. These UAVs carry a very competitive 40-kilogram payload, offer long running times, have a good wind field effect, and are easy to operate and maintain. 

Mr. Zhang, the technical manager at SLZY, says: “The Houji series offers technical performance, efficiency, and effect advantages compared to competing UAVs when facing large-scale crop planting and protecting cash crops, such as fruit trees and cotton.” 

However, initially, the high-speed vibrations generated by the rotor often caused bolts to loosen. SLZY used spring gaskets and friction to prevent this problem, but the anti-loosening effect was unreliable due to uneven elasticity. 

 

Looking for a better bolting solution 

It was not uncommon for customers to need frequent maintenance as bolts were coming loose. As a result, their UAV operation time could be short and the workload heavy. 

SLZY started looking for another way to secure the engines, rotors, and antenna fixtures to solve the problem. They found it in Nord-Lock wedge-locking washers. 

Unlike the spring gaskets, Nord-Lock washers use geometry instead of friction to prevent bolt loosening. The system is composed of a pair of lock washers with cams on one side and radial teeth on the other. The wedge-locking principle ensures that any rotational movement occurs between the cam faces. 

 

Greatly reduces maintenance 

“Because of the excellent locking performance of the Nord-Lock anti-loosening washer, we no longer need to carry out frequent inspections or repairs. Our customers tell us that it greatly extends the UAV’s running time and improves the stability,” says Mr. Zhang. 

The Houji UAVs are now used across China, meeting the different requirements and terrain challenges of large-scale plant protection for grain production, fruit trees, and cotton. Now more stable and robust, Houji series UAVs will continue to help develop efficient and modern plant protection in China.