U-Shaped Spring Locknut for Vibration-Resistant Reuse
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Solution Overview
Problem
Bolts and nuts in machinery and vehicle environments often loosen due to vibration and thermal expansion/contraction, leading to safety hazards and increased costs with existing locknuts that are costly and not easily removable.
Innovation Solution
A metallic nut with a bifurcated U-shaped spring member that applies frictional pressure to prevent unauthorized unthreading, using a U-shaped spring member inserted through an access opening into a pocket, which contacts the threaded member to prevent longitudinal movement and disengagement, with various embodiments optimizing leg shape and arrangement for different thread configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locknuts are used to prevent loosening, then the nut remains secure against vibration and thermal expansion, but the manufacturing cost increases substantially and the locknut cannot be easily removed and reused
Solution Approach 1:
The locknut is divided into two separate components: a conventional nut body and a distinct U-shaped spring member. The spring member is inserted through an access opening in the nut body, allowing the locking function to be separated from the nut structure. This segmentation enables the nut body to remain simple and inexpensive while the spring member provides the locking action, reducing overall manufacturing cost compared to integrated locknut designs.
Solution Approach 2:
The spring member is designed to be removable and reusable. When the nut needs to be removed, the spring member can be taken out and reused on another fastener, while the conventional nut body can be reused without destruction. This recoverability reduces long-term costs compared to conventional locknuts that must be destroyed upon removal.
2Reliability
If conventional locknuts are used to prevent unauthorized unthreading, then the threaded member remains secured, but the complexity of the device increases and requires special tools for installation and removal
Solution Approach 1:
The locking function is segmented into a separate U-shaped spring member that can be independently installed through an access opening. This separates the locking mechanism from the nut body, simplifying the overall structure and eliminating the need for complex integrated locknut designs that require special installation tools.
Solution Approach 2:
The spring member acts as an intermediary element that provides the locking action between the nut body and the threaded member. It applies frictional pressure through its bowed leg members against the threaded member, preventing unauthorized unthreading without requiring the nut itself to be complex or specialized.
3Reliability
If the spring member applies frictional pressure to prevent loosening, then the threaded member remains secure under vibration and thermal stress, but the spring member may interfere with the threaded member's longitudinal movement
Solution Approach 1:
The spring member's frictional pressure is applied locally at specific contact points on the threaded member's outer surface, rather than uniformly across the entire interface. The bowed leg members contact the threaded member at discrete locations, providing sufficient frictional resistance to vibration and thermal stress while leaving other areas free for longitudinal movement during installation and removal.
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 solution effectively prevents unauthorized disengagement of threaded members, ensuring safety and reducing manufacturing costs by allowing for reusability of locknuts, making them more viable for high-volume production without significant cost increases.
Implementation Method 1
The bowed leg members are to apply a frictional pressure onto the threaded member preventing unauthorized unthreading and disengagement of the threaded member from the nut body
Implementation Method 2
The U-shaped spring member has a pair of spaced apart leg members (which forms the bifurcation) each of which is slightly bowed toward each other providing the spring action
Data Source
AI summary
A locknut which uses a U-shaped spring member that is mounted in a nut body that applies frictional pressure onto a threaded member that engages with said nut body.