Concealed Slide Fastener Structure for Tensile Load Resistance
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Solution Overview
Problem
Hidden or seam-concealed slide fasteners used in attaching fabric covers to objects like furniture or vehicle seats often become visible due to tensile forces, as they are not designed for removal and are fitted tightly, leading to visible exposure during normal use.
Innovation Solution
The slide fastener features a pair of stringer tapes with stiffened regions made of two-component yarn, which are layered and connected in an interlocking manner with coupling members, providing additional strength and concealing the fastener under tensile load by abutting against each other, mimicking a seam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fabric cover is fitted tightly to remain permanently in position, then the attachment reliability is improved, but the slide fastener becomes visible under tensile load
Solution Approach 1:
The stringer tapes are given different local properties: the first stringer tape portion has a stiffened region with increased rigidity to resist tensile forces and maintain concealment, while the second stringer tape portion remains flexible for normal operation. This local differentiation allows the fastener to remain concealed under load while maintaining functionality.
Solution Approach 2:
The stiffened region is formed using composite construction with multiple layers including a base fabric layer and a stiffening layer (such as thermoplastic or woven stiffening material). This composite structure provides the necessary mechanical strength to counteract tensile forces while maintaining the overall flexibility of the stringer tape.
2Strength
If the fabric cover is fitted extremely tightly for permanent attachment, then the attachment strength is improved, but the tensile forces cause the slide fastener to become visible
Solution Approach 1:
The stiffened region is positioned specifically in the area where tensile forces act on the stringer tapes, providing localized reinforcement only where needed. This allows the stringer tapes to maintain sufficient flexibility in other areas while resisting visibility-causing forces at the critical location.
Solution Approach 2:
The stiffened region acts as a counterbalancing element that resists the tensile forces trying to pull the stringer tapes apart and make the fastener visible. The increased rigidity creates a counteracting force that maintains the concealed appearance under load.
3Shape
If additional stiffening is added to the stringer tapes, then the concealment under tensile load is improved, but the device complexity increases
Solution Approach 1:
The stiffening function is integrated directly into the stringer tape structure itself rather than being a separate component. The stiffened region is formed as part of the stringer tape assembly, combining the tape and stiffening elements into a single integrated unit that reduces overall device complexity.
Solution Approach 2:
The stiffened region is pre-formed and integrated into the stringer tapes before assembly. This preliminary preparation allows the stiffening function to be built-in during manufacturing rather than requiring additional assembly steps or adjustable components, thereby simplifying the final device structure.
Data Source
AI summary
A slide fastener has a pair of stringer tapes and coupling members each fastened to the stringer tapes in a row. The rows of coupling members lie opposite one another and connect the two stringer tapes to one another in an interlocking manner. Each stringer tape is formed from two stringer tape portions, the coupling members each rest against a first stringer tape portion, and a second stringer tape portion is arranged on the side of the first stringer tape portion facing away from the coupling members. The first stringer tape portion and second stringer tape portion of stringer tapes are bent and connected to each other at a stringer tape region. A slider is designed such that a movement of the slider in a first direction connects the coupling members of the stringer tapes in an interlocking manner and releases them in an opposite direction.