Fastener Thread Height Control for Shorter Anti-Cross Threading
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Solution Overview
Problem
Existing anti-cross thread fasteners have a fixed transitional thread contour length that is longer than ideal due to manufacturing limitations, leading to wasted space in the thread rolling die and non-functional transitional thread sections.
Innovation Solution
Reconfigure the transitional thread contour to have a variable and controlled peak height, reducing its length to one-quarter turn shorter while maintaining full anti-cross thread functionality by ensuring the thread rolling die fills completely and eliminating non-functional sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transitional thread contour length is increased to ensure complete filling in thread rolling die, then manufacturing reliability is improved, but fastener length and weight increase
Solution Approach 1:
The patent applies local quality by varying the thread contour height at different locations along the transitional thread. Specifically, the thread contour height is reduced in the later portion of the transitional thread (after the first half turn) compared to the earlier portion, creating localized modifications that enable complete die filling while minimizing overall fastener length.
Solution Approach 2:
The patent changes the thread contour height parameter along the length of the transitional thread. The thread contour height transitions from full height at the beginning of the transitional thread to a reduced height in the later portion, allowing the thread rolling die to fill completely during the critical early forming stages while reducing material volume and fastener length.
2Length of moving object
If the transitional thread contour length is reduced to eliminate non-functional sections, then fastener length and cost are reduced, but manufacturing precision may be compromised
Solution Approach 1:
The patent concentrates the thread contour height reduction in the later portion of the transitional thread, maintaining full thread contour height in the critical first half turn where complete die filling occurs. This localized modification preserves manufacturing precision in the most critical forming region while still achieving length reduction.
Solution Approach 2:
The patent ensures that the thread rolling die fills completely during the critical early portion of the transitional thread (first half turn) before the contour height is reduced. This preliminary complete filling action guarantees manufacturing precision is achieved in the most important forming stage.
3Weight of moving object
If the thread contour height is reduced in transitional thread, then fastener weight and cost are reduced, but thread engagement functionality may be compromised
Solution Approach 1:
The patent maintains full thread contour height in the critical engagement region (standard thread portion and first half of transitional thread) where thread engagement functionality is most important. The height reduction is applied only in the later portion of the transitional thread where engagement functionality is less critical.
Solution Approach 2:
The patent ensures full thread contour height is present during the preliminary and critical thread engagement phases, including the entire standard thread portion and the first half turn of the transitional thread, before reducing height in less critical regions.
4Productivity
If the transitional thread contour is optimized to one-quarter turn length, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent implements a relatively simple local modification to the thread contour - reducing height only in the later portion of the transitional thread. This localized change is easy to implement in the thread rolling die design and process, achieving productivity improvement without excessive complexity.
Data Source
AI summary
A male anti-cross threading fastener comprising: a substantially round shank having a lead end, a torque end, and a plurality of male threads around a circumference of the shank, the plurality of male threads comprising: a standard thread around at least a portion of the circumference of the shank and having a standard thread contour, wherein a width and a thread angle of the standard thread enables engagement with corresponding female threads, wherein the major diameter of the standard thread is between a lower major diameter limit and a higher major diameter limit; a transitional thread around at least a portion of the circumference of the shank and having a transitional thread contour with a width and a thread angle similar to the width and thread angle of the standard thread that enables engagement with corresponding female threads; an anti-cross thread around at least a portion of the circumference of the shank and having an anti-cross thread contour and an outside diameter configured to promote alignment of the male anti-cross thread fastener with a female fastener; and a lead thread around at least a portion of the circumference of the shank and having a lead thread contour, and wherein the transitional thread contour has a height that transitions from the lower major diameter limit of the standard thread to the outside diameter of the anti-cross thread.