Slide Fastener Flange Protrusion Design for Stringer Separation
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Solution Overview
Problem
Existing slide fasteners can experience issues where fastener elements are damaged due to prolonged pressure from flanges, and there is a risk of the slider becoming inclined or stopped during separation, leading to incomplete snapping of fastener elements.
Innovation Solution
A slide fastener design featuring a slider with upper and lower blades, guide posts, and flanges where the opposing surfaces at one side have protrusions and straight portions, allowing for easy separation of fastener stringers and preventing damage by maintaining the passage of fastener elements through the tape insertion path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gap of the tape insertion path gradually narrows from the shoulder mouth side toward the rear mouth side, then the slider can be snapped, but the snapping may be stopped on the way when the slider is slowly snapped because the next fastener element cannot pass through the tape insertion path
Solution Approach 1:
The tape insertion path is designed with a dynamic gap width that changes along its length. The gap is wider at the shoulder mouth side and gradually narrows toward the rear mouth side, allowing the path to adapt to the progression of fastener elements during snapping. This dynamic geometry ensures that each successive fastener element can pass through the tape insertion path even as previous elements have already passed, preventing the snapping operation from stopping midway.
2Device complexity
If the flanges are configured such that the gap of the tape insertion path is uniform from the shoulder mouth side to the rear mouth side, then the structure is simple, but if a twisting operation is strongly applied, the slider may be inclined and stopped because some fastener elements get out of the tape insertion path
Solution Approach 1:
The flanges are configured with an asymmetric gap width in the tape insertion path, where the gap is wider at the shoulder mouth side and narrower at the rear mouth side. This asymmetric design provides a larger clearance zone at the entry point that accommodates twisting operations and prevents fastener elements from getting out of the tape insertion path, while still maintaining a controlled narrowing toward the rear to guide proper alignment.
3Ease of operation
If fastener elements are pressed by the flanges of the tape insertion path for a long time, then the fastener elements may be damaged, but the flanges are needed to guide the fastener elements
Solution Approach 1:
The flanges are designed with locally varied properties along their length. The gap width between opposing flanges changes progressively from a wider width at the shoulder mouth side to a narrower width at the rear mouth side. This local variation in geometry allows the flanges to provide guiding function where needed while reducing pressing force in critical areas, preventing damage to fastener elements that may be pressed by the flanges during operation.
Data Source
AI summary
There is provided a slide fastener in which one of the fastener stringers is separated from a tape insertion path at one side of a body in the width direction when a lateral pulling force directed outward in the width direction of the fastener tapes is applied to a pair of fastener stringers. At least one opposing surfaces of an upper and lower flange at one side of the body in the width direction has a protrusion on the rear end portion thereof, and the opposing surfaces of the upper and lower flanges at one side of the body in the width direction respectively have straight portions which are parallel with each other except for the position at which the protrusion is formed.