Slide Fastener Element With Chamfered Margins For Smooth Feel And Strength
Solution Overview
Problem
The existing metal fastener elements for slide fasteners have rough edges that cause a prickling or scratched feel when the hand is inserted, and their design leads to a decrease in strength during transverse pulling and bending due to thin thickness at the tip end portion.
Innovation Solution
A fastener element with a coupling head and leg portions, featuring a center first margin portion and inclined second margin portions on either side, which are chamfered to provide a smooth surface, maintaining thickness and preventing deformation, thus enhancing the sliding feel and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the center margin portion is rounded to improve smooth feel, then the sliding smoothness is improved, but the thickness at the tip end portion becomes thin causing deformation and strength decrease
Solution Approach 1:
The patent applies different surface treatments to different regions of the coupling head. Specifically, the outer edge portions are rounded to provide smoothness for sliding operation, while the center margin portion maintains its original shape with sufficient thickness to ensure structural strength during transverse pulling and bending operations.
Solution Approach 2:
The coupling head surface is divided into distinct regions: rounded outer edge portions for smooth sliding contact, and a non-rounded center margin portion for maintaining structural integrity. This segmentation allows each region to fulfill its specific function without compromising the other.
2Ease of operation
If outer edge portions are rounded to reduce noise and improve sliding, then the sliding resistance is reduced, but the manufacturing complexity increases due to additional processing steps
Solution Approach 1:
Only the outer edge portions of the coupling head are rounded, while the center margin portion and other critical structural areas maintain their original geometry. This localized treatment reduces manufacturing complexity compared to complete rounding, while still achieving the desired reduction in sliding resistance and noise.
Data Source
Figure 1
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Figure 4~5
AI summary
A fastener element (10, 30) of the invention includes a coupling head (11, 31) and a pair of leg portions (13, 33) and has a coupling concave portion (14) provided on a first surface of the coupling head (11, 31) and a coupling convex portion (15) projecting from a second surface of the coupling head (11, 31). An outer margin portion on a first surface side of the coupling head (11, 31) has a first margin portion (17a) formed like a ridge line and a pair of second margin portions (17b, 37b) disposed on both sides of the first margin portion (17a) and formed like an inclined surface or a curved surface and one end of each of the second margin portions (17b, 37b) is arranged on an inside of both end positions of a width direction of the coupling concave portion (14). Accordingly, the feel of the fastener element (10, 30) can be improved and also the strength of the slide fastener with respect to transverse pulling can stably be maintained.