Variable-Pitch Threaded Connection for Self-Locking Without Jamming
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Solution Overview
Problem
Conventional threaded connections, such as screws and nuts, lack self-locking capabilities, especially under high temperatures and in applications requiring adjustable fit, leading to loosening and potential breakage, and existing self-locking nuts are limited by their design and temperature constraints.
Innovation Solution
A threaded connection element with a variable pitch thread system that allows for self-locking without jamming or breaking, applicable to both bolts and nuts, enabling secure fit without the need for additional nuts and suitable for high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional screw with a standard nut is used to maintain a tight connection, then the connection is secure, but the components can loosen over time and require additional locking mechanisms
Solution Approach 1:
The patent applies a variable pitch thread design where the thread spacing changes along the length of the screw. This dynamic geometric variation creates alternating zones of different friction characteristics, allowing the connection to maintain security while preventing loosening through self-locking mechanisms at specific thread sections.
Solution Approach 2:
Different sections of the thread have different pitch values, creating local variations in mechanical properties. The varying pitch zones provide localized self-locking effects at specific positions along the thread, while other zones maintain standard engagement characteristics, thus achieving both security and durability.
2Reliability
If a self-locking nut with an inner nylon washer is used to prevent loosening, then the connection is secure, but the device cannot be used under high temperatures and has limited uses
Solution Approach 1:
The patent replaces the nylon washer mechanical locking system with a variable pitch thread geometric locking system. This substitution eliminates the temperature sensitivity and material degradation issues of nylon, allowing the self-locking mechanism to function reliably under high temperatures and through multiple uses.
Solution Approach 2:
The thread pitch parameter is varied along the length of the screw to create self-locking zones. This geometric parameter change provides temperature-independent locking capability, unlike material-based solutions such as nylon washers that degrade at high temperatures.
3Reliability
If a variable pitch thread system is applied to enable self-locking, then the connection prevents loosening, but the threading complexity increases
Solution Approach 1:
The thread is divided into multiple sections with different pitch values along its length. This segmentation creates distinct functional zones: some sections provide standard engagement while others provide self-locking effects, simplifying the overall design compared to a completely variable pitch system.
Solution Approach 2:
Instead of varying the pitch continuously, the patent applies discrete pitch variations at specific local zones. This approach achieves self-locking functionality while maintaining simpler manufacturing processes compared to continuously variable pitch threads.
Data Source
AI summary
A self-locking threaded connection element can be a screw or a nut, and includes a thread with a set of several turns. The thread has a thread pitch which varies from one turn to another and which enables the element to be self-locking, without seizing.