Slide Fastener Chain Fluid Tightness via Coupling Element Segmentation
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Solution Overview
Problem
Conventional slide fasteners are not fluid and/or gas tight when in a closed configuration, making them unsuitable for applications requiring watertightness, such as garments or luggage, and are often costly and complex to manufacture.
Innovation Solution
A slide fastener chain design featuring coupling elements with a shoulder, head, and neck portions, where the head and neck portions of one stringer interdigitate with the groove of the other, creating a seal along the entire length of the fastener chain without additional features, using impermeable materials for the tapes and cords to prevent fluid passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional slide fasteners are used, then the fastening function is achieved, but the fastener is not fluid and/or gas tight
Solution Approach 1:
The coupling element is segmented into distinct functional portions: a head portion with a groove, a neck portion, and a body portion. This segmentation allows each portion to perform its specific sealing function independently, creating multiple sealing interfaces that collectively achieve fluid tightness without requiring complex additional components
Solution Approach 2:
The head portion of the coupling element features a groove with specific local geometric properties that create a sealing interface with the tape. This local modification of the coupling element geometry enables fluid tightness at the critical sealing location without altering the overall fastener structure significantly
2Reliability
If additional sealing features are added to achieve watertightness, then fluid tightness is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The sealing function is merged with the coupling function by integrating the groove feature directly into the coupling element's head portion. This eliminates the need for separate sealing components or features, as the same coupling element that joins the tapes also creates the fluid tight seal through its groove geometry
Solution Approach 2:
The coupling element is designed to perform multiple functions simultaneously: it provides mechanical coupling between tapes through interdigitiation, creates fluid tight sealing through the groove-tape interface, and maintains structural integrity. This multi-functionality eliminates the need for additional dedicated sealing components
3Reliability
If the coupling elements are designed with groove and neck portions for sealing, then fluid tightness is achieved, but the fastener resistance to burst forces is enhanced
Solution Approach 1:
The groove in the head portion and the neck portion are pre-configured to create interference fit relationships with the tape and adjacent coupling elements. This preliminary geometric configuration ensures that sealing contact and burst force resistance are inherently built into the structure before the fastener is subjected to operational loads
Data Source
AI summary
A slide fastener chain includes first and second rows of coupling elements mounted on first and second longitudinal edges of the first and second fastener tapes. When the first and second rows of coupling elements are interdigitated, the first and second longitudinal edges remain spaced apart, and a first coupling element of the first row is received between two adjacent coupling elements of the second row such that: the groove of the first coupling element receives, in a first contact region, a portion of the second longitudinal edge, one of the grooves of the adjacent coupling elements receives, in a fourth contact region, a first portion of the first longitudinal edge, and another of the grooves of the adjacent coupling elements receives, in a fifth contact region, a second portion of the first longitudinal edge.