Concealed Fastener Slider Flange Geometry to Prevent Tape Catching
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Solution Overview
Problem
Conventional sliders for concealed slide fasteners experience increased contact stress and flange tips catching or biting into fastener tapes, particularly with thin fabrics or fabrics with rough yarn weaves, leading to difficulty in pulling up the slider and potential damage to the fastener tapes.
Innovation Solution
The slider design includes flanges with a front end located forward of the rails and a start point of the flange inner-front curved portion positioned behind the rail end, along with a larger radius of curvature for the inner-front curved portion, reducing contact stress and preventing flange tips from catching or biting into the tapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flanges protrude forward beyond the rails to engage the tape folding portions, then the slider can effectively grip and move the fastener tapes, but the contact stress between flanges and tapes increases causing flange tips to catch or bite into the tapes
Solution Approach 1:
The flange inner-front curved portion is designed with a specific radius of curvature (1.2mm to 2.0mm) to create a rounded transition zone. This curvature prevents the flange tips from concentrating stress on sharp edges, thereby eliminating the biting or catching phenomenon while maintaining effective engagement with the tape folding portions
Solution Approach 2:
The patent optimizes the position of the flange inner-front curved portion start point relative to the rail front end, and controls the radius of curvature within specific ranges. These parameter adjustments reduce contact stress by distributing the load over a larger area and creating a more gradual transition zone between the flange and tape
2Reliability
If the flanges are designed to engage thin or rough fabrics effectively, then the slider can securely grip the fastener tapes, but the flange tips are more likely to bite into the delicate fabric and cause damage
Solution Approach 1:
The curved portion of the flange with radius of curvature between 1.2mm to 2.0mm creates a rounded contact surface that distributes pressure evenly across the fabric. This prevents concentration of stress at sharp flange edges, thereby avoiding biting or catching of thin and rough fabrics during slider operation
Solution Approach 2:
The flange is designed with different geometric characteristics at different locations: the inner-front curved portion has a specific radius to gently engage the fabric, while other portions maintain structural integrity. This localized geometric optimization allows effective grip on delicate fabrics without causing damage
Data Source
AI summary
A slider for a concealed slide fastener includes: a lower blade; a pair of left and right rails erected along side edges of the lower blade in a left-right direction; left and right flanges extending in a direction in which the left and right flanges approach each other from upper ends of the pair of left and right rails; a guide column erected on the lower blade; and an attachment column provided above the guide column. A front end portion of each of the flanges is located forward with respect to a front end portion of each of the rails. A start point of a flange inner-front curved portion is located behind the front end portion of each of the rails.