Mushroom-Type Hook Strap Polygonal Head Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mushroom-type hook straps for mechanical fasteners suffer from low engaging percentages, short lifetimes, and directional fastening limitations, leading to insufficient reliability and damage to fabric loops during engagement and disengagement.
Innovation Solution
A method involving a rotational molding roller with Y-shaped cavities and calendar rolls to form hook straps with tetragon pegs that are deformed into polygonal heads, 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 detaching
Solution Approach 1:
The patent applies asymmetry by changing the hook head shape from circular to polygonal (triangle, quadrangle, pentagon, or hexagon). This asymmetric shape creates protruding portions that engage with fabric loops more effectively, increasing the engaging percentage. The polygonal geometry ensures that during detaching operations, the hooks do not fully insert into the loops, preventing the lockup-type engagement that causes loop destruction, thereby extending the lifetime of the fastener while maintaining reliable fastening capability.
2Reliability
If elliptic-headed mushroom-type hooks are used, then the engaging percentage and fastening strength are improved, but the fastening function becomes directional and unreliable under perpendicular impact forces
Solution Approach 1:
The patent uses asymmetric polygonal shapes (triangle, quadrangle, pentagon, or hexagon) instead of elliptic heads. These polygonal shapes provide protruding portions in multiple directions around the hook head, enabling effective engagement with fabric loops regardless of the direction of applied force. This resolves the directional limitation of elliptic-headed hooks while maintaining high fastening strength and reliability under various loading conditions including perpendicular impact forces.
3Ease of manufacture
If traditional hook shapes are used, then the manufacturing process is simple, but the engaging percentage is low and sufficient fastening strength cannot be provided
Solution Approach 1:
The patent employs preliminary action by forming the hook preforms with the desired polygonal head shape directly during the extrusion and cooling process on the molding roller, before the final shaping operation. This preliminary formation of the polygonal geometry with protruding portions enables effective engagement while maintaining a relatively simple manufacturing process that integrates shaping into the existing production line.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the hook head from circular or elliptic shapes to polygonal shapes with specific numbers of sides (triangle, quadrangle, pentagon, or hexagon). This geometric parameter change creates protruding portions that significantly increase the engaging percentage with fabric loops while maintaining compatibility with the existing manufacturing process through adjustments to the molding roller cavities and shaping roller configuration.
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 enhances engaging percentages, extends the lifespan of the hook straps, and ensures reliable, all-directional uniform fastening without damaging fabric loops.
Implementation Method 1
cooling the thermoplastic material on the outer periphery surface of the rotational molding roller and within the substantially Y-shaped molding cavities with the cooling device so as to form a hook strap on which an plurality of hook preforms are molded
Implementation Method 2
the calendar roll that contacts the V-shaped free end of the hook preforms is heated to a temperature above a plastic deforming temperature of the plastic material so as to deform the V-shaped free end of each hook preform
Data Source
Figure 1a~1b
Figure 2a~3b
Figure 4
AI summary
A method for making a mushroom-type hook strap for mechanical fasteners is disclosed. In a first stage of the method, a hook strap on which a plurality of hook preforms each having a substantially V-shaped free end are integrally molded. Then, in a second stage of the method, the V-shaped free end of each of the hook preforms is deformed into a polygonal head portion by two calendar rolls so as to form a mushroom-type hook strap that has a higher engaging percentage with the loop strap, has a longer lifetime, and is capable of providing a reliable and all-directional uniform fastening function.