Off-Center Lock Nut Assembly for Vibration-Resistant Bolts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bolts and nuts tend to loosen due to vibrations, especially on low-angle slope threads, compromising installations and potentially leading to malfunctions or accidents in various equipment and structures.
Innovation Solution
A nut and bolt system featuring an upper nut with a low taper shank and a lower nut with a socket for self-holding, where the upper nut is slightly off-centered, increasing the spiral contact area and applying pressure to securely lock the bolt in place, preventing loosening from vibrations by using precision threading to minimize clearance and enhance thread engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard bolt and nut are used, then the structure is simple and easy to manufacture, but the nut loosens under vibration
Solution Approach 1:
The fastening system is divided into multiple components: a lower nut with external threads, an upper nut with internal threads, and a bolt. The upper nut is segmented into a cylindrical portion and a tapered portion, creating a multi-part system that prevents loosening through relative movement and friction between segments.
Solution Approach 2:
The upper nut is nested within the lower nut, with the tapered portion of the upper nut fitting into the lower nut. This nested configuration allows the two nuts to work together as an integrated anti-loosening system while maintaining a compact structure.
2Strength
If the nut is tightened to increase thread engagement, then the connection strength increases, but the clearance between threads increases allowing vibration loosening
Solution Approach 1:
The upper nut incorporates a tapered portion with a specific taper angle (e.g., 60 degrees) that changes the geometric parameters of the nut-bolt interface. This taper creates a wedging action that converts axial tightening force into radial clamping force, increasing friction and preventing thread clearance from allowing vibration-induced loosening.
Solution Approach 2:
The tapered portion of the upper nut introduces a curved surface geometry instead of a cylindrical shape. This curvature creates a wedge effect that generates frictional force opposing the direction of vibration-induced loosening, thereby stabilizing the thread engagement under vibrational loads.
3Reliability
If a lock tight bolt-nut system with tapered portion is used, then vibration loosening is prevented, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into standard operations: the lower nut is manufactured as a standard threaded component, while the upper nut is manufactured with a distinct tapered portion. This segmentation allows each component to be produced using conventional machining processes, avoiding the need for complex specialized manufacturing while achieving the anti-loosening function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively prevents nut loosening under vibrations by increasing the spiral contact area and thread engagement, providing a substantial force to maintain the bolt-nut connection, ensuring secure assembly and reducing the risk of malfunctions or accidents in machinery and structures.
Implementation Method 1
upper nut has a low taper shank and a lower nut has a socket for self-holding
Implementation Method 2
shank and socket guide bolt to the off-centered threads. When this happens, the bolt is forced to move towards its center
Implementation Method 3
upper nut has a very slightly off-centered thread center. When the upper nut tightens onto the bolt, the upper nut touches on the top of the bolt, then the shank and the socket guide bolt to the off-centered threads. When this happens, the bolt is forced to move towards its center, and the upper nut reacts to push back in the opposite direction. This force exerts on the spiral contact zone for bolt-nut lock tightening.
Data Source
AI summary
A lock tight nut and bolt system resistant to loosening due to vibration. The lock tight nut and bolt system includes an upper nut that has a shank part. The upper nut has first threads that are off center from a center of a bolt. The upper nut is configured to receive the bolt. A lower nut has a socket part and second threads that are centered with the center of the bolt. The socket part corresponds with the shank park of the upper nut. The upper nut and the lower nut are concentric with the center of the bolt. The system further may include the bolt.