Anti-Cross-Threading Thread Configuration with Variable Helix Angles
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Solution Overview
Problem
Threaded connections are prone to cross-threading, which can interfere with sealing functions and damage components due to misalignment of thread axes.
Innovation Solution
The solution involves configuring mating threads with offset starting points and varying helix angles, where leading portions have a lesser helix angle than trailing portions, to ensure sequential engagement and prevent cross-threading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded connections are used, then ease of manufacture is maintained, but cross-threading occurs causing misalignment and sealing failures
Solution Approach 1:
The thread is segmented into two distinct portions: a leading portion with a first helix angle and a trailing portion with a second helix angle. This segmentation allows the thread to perform different functions at different stages of engagement, with the leading portion facilitating initial alignment and the trailing portion providing secure fastening, thereby preventing cross-threading while maintaining manufacturing feasibility
Solution Approach 2:
Different portions of the same thread are given different local qualities through varying helix angles. The leading portion has a first helix angle optimized for alignment, while the trailing portion has a second helix angle optimized for fastening. This local differentiation enables the thread to prevent cross-threading without requiring an entirely new thread design
2Reliability
If threads with varying helix angles are used, then cross-threading is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the helix angle parameter along the length of the thread, transitioning from a first helix angle in the leading portion to a second helix angle in the trailing portion. This parameter variation is designed to be robust against manufacturing tolerances, ensuring that the functional benefits of cross-threading prevention are achieved without requiring extreme precision in helix angle control
3Ease of operation
If offset thread starting points are used, then sequential engagement is achieved, but device complexity increases
Solution Approach 1:
The leading portion of the thread with its distinct helix angle performs the preliminary action of guiding and aligning the mating threads before full engagement occurs. This preliminary alignment action prevents cross-threading from occurring in the first place, making the overall engagement process easier and more reliable without requiring complex adjustment mechanisms
Data Source
AI summary
A threaded closure system includes a threaded opening and a threaded closure, where at least one thread of the threaded opening or the threaded closure has a leading portion with a steeper angle than the rest of the thread.