Sloped Cap Hook Fastener for Stronger Loop Engagement
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Solution Overview
Problem
Hook and loop attachment devices often exhibit inefficiencies and inadequate attachment strength, leading to unintended disengagement in various applications.
Innovation Solution
A hook fastener design featuring a stem with lateral edges, a cap extending from the upper end, and overhanging portions that are sloped and angled to enhance engagement with loop attachment structures, along with a manufacturing process that includes tilting the deforming portion of the intermediate component between rollers to form the cap, increasing the attachment strength and ease of engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hook fastener design is used, then manufacturing is simple, but attachment strength is inadequate
Solution Approach 1:
The hook fastener is divided into distinct functional segments: a stem portion and a cap portion with overhanging portions. This segmentation allows each part to perform its specific function optimally - the stem provides structural support while the cap with overhanging portions creates multiple engagement points with the loop attachment structure, thereby increasing attachment strength without excessive complexity
Solution Approach 2:
The overhanging portions extend laterally from the stem in directions perpendicular to the main stem axis, adding a lateral dimension to the engagement geometry. This dimensional change allows the hook fastener to engage the loop attachment structure at multiple points and angles, significantly enhancing attachment strength while maintaining manufacturability through standard molding processes
2Reliability
If conventional hook fastener design is used, then structure is simple, but engagement reliability is poor
Solution Approach 1:
By segmenting the hook fastener into a stem and a cap with overhanging portions, the design ensures that the engagement force is distributed across multiple contact points between the overhanging portions and the loop attachment structure. This segmentation prevents unintended disengagement by requiring simultaneous failure of multiple engagement points, thereby improving reliability
Solution Approach 2:
The overhanging portions are pre-formed during the molding process to extend laterally before engagement occurs. This preliminary configuration ensures that when the hook fastener engages with the loop attachment structure, the overhanging portions are already positioned to create secure mechanical interlocking, improving engagement reliability without requiring complex assembly steps
3Strength
If sloped cap design with overhanging portions is used, then attachment strength increases, but manufacturing complexity increases
Solution Approach 1:
The stem and cap portions with overhanging portions are formed as a single integrated component in one molding operation. This merging of forming operations eliminates the need for separate manufacturing steps to create the overhanging portions, thereby maintaining ease of manufacture while achieving enhanced attachment strength through the sophisticated geometry
Solution Approach 2:
The molding process parameters are optimized to directly form the sloped cap surface and laterally extending overhanging portions in a single shot. By changing the mold cavity geometry and processing parameters rather than adding post-forming steps, the design achieves complex geometry with standard manufacturing methods, maintaining ease of manufacture while improving attachment strength
Data Source
AI summary
A hook fastener includes a stem having two lateral edges, a first surface, and a second surface. A cap extends from an upper end of the stem, and the cap includes an upper surface, a first end, a second end, and a pair of overhanging portions. The upper surface of the cap is sloped between the first end and the second end. The first and second ends are at opposite longitudinal ends of the cap, and each overhanging portion extends in a lateral direction from the stem.