Polygonal Head Mushroom Hooks for Uniform Fastening
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Solution Overview
Problem
Existing mushroom-type hook straps for mechanical fasteners have low engaging percentages, short lifetimes, and provide non-uniform, directional fastening functions, leading to unreliable engagement and loop damage during use.
Innovation Solution
A method involving a rotational molding roller with Y-shaped cavities and an extruder to form thermoplastic hook straps with V-shaped preforms, which are then deformed into polygonal head hooks using calender rolls, providing increased engagement and uniform fastening capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circular-headed mushroom-type hooks are used, then the fastening function is provided, but the engaging percentage is low and the lifetime is short due to loop destruction during detachment
Solution Approach 1:
The patent applies asymmetry by changing the hook head shape from circular to non-circular forms such as elliptic, rectangular, or polygonal heads. This asymmetric geometry creates protruding portions that engage with fabric loops more effectively, increasing the engaging percentage and preventing loop destruction during detachment, thereby extending the hook strap lifetime while maintaining fastening reliability.
Solution Approach 2:
The patent applies local quality by creating specific geometric features (protruding portions) at critical locations on the hook head surface. These localized structural modifications at the head-periphery interface enable selective engagement with fabric loops, improving both reliability and durability without requiring changes to the entire hook structure.
2Strength
If elliptic-headed mushroom-type hooks are used, then the engaging percentage and fastening strength are improved, but the fastening function becomes directional rather than uniform in all directions
Solution Approach 1:
The patent uses asymmetric polygonal head shapes (such as rectangular, triangular, or multi-sided polygons) that provide protruding portions distributed around the head periphery. This asymmetric design maintains the directional engagement advantages while creating multiple engagement points that enable more uniform fastening performance across different orientations compared to simple elliptic heads.
Solution Approach 2:
The patent transitions from two-dimensional elliptic head profiles to three-dimensional polygonal head structures with multiple faces and protruding portions. This dimensional evolution creates engagement capabilities in multiple directions simultaneously, enabling the hooks to provide more uniform fastening strength regardless of the direction of applied load or orientation of the loop strap.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a hook strap with a higher engaging percentage, longer lifetime, and reliable all-directional uniform fastening, preventing loop damage during detachment and enhancing overall fastening performance.
Implementation Method 1
extruding melted thermoplastic resin 1 from the extruder 2 into a plurality of die cavities 4 formed in an outer periphery of a molding roller 3
Implementation Method 2
cooling the molding roller 3 to form a hook strap 7 on which a plurality of upstanding stems 6 are molded
Implementation Method 3
the shaping roller that contacts the stems heats the free end of the stems to a temperature above a flow point of the thermoplastic reason to shape the stems into hooks
Data Source
AI summary
A mushroom-type hook strap for mechanical fasteners has a series of hooks integrally formed on the strap, with each hook formed by a polygonal shape situated on top of an axis of a single stem, thereby forming a mushroom type hook having a polygonal head portion on the axis of the single stem, with protruding portions in substantially every direction for engaging fabric loops of a loop strap.