Composite Knob Fastening Device for Lace Tensioning
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Solution Overview
Problem
Existing fastening devices using cords or laces for securing articles face issues such as loose knots, insecurity due to external forces, and structural limitations, including weight and cost concerns with metal-based buckles.
Innovation Solution
A fastening device featuring a case unit with a spool for winding the lace and a composite material knob with a metal shield cover, allowing for adjustable tension through rotation, which reduces weight and cost while maintaining structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-based fastening mechanism is used to clamp the lace, then the lace can be fastened through reaction force, but the restoring force of the spring causes the lace to be easily released due to vibrations or external force
Solution Approach 1:
The patent changes the fundamental parameter of the fastening mechanism from a spring-based elastic system to a friction-based static system. By using a knob that presses against the lace to create friction, the system transforms from dynamic (spring restoring force) to static (friction resistance), thereby preventing lace release under vibration or external force while maintaining fastening security.
Solution Approach 2:
The patent employs composite material structure in the knob, combining a metal shell for structural strength and friction resistance with a plastic or polymer inner core for weight reduction and cushioning. This composite construction enhances the knob's ability to maintain stable friction-based fastening while reducing overall device weight and improving resistance to external forces.
2Strength
If a metal-based buckle is used to tension the lace, then the structure provides strength and stability, but the device becomes heavy and expensive
Solution Approach 1:
The patent applies composite materials by constructing the knob with a metal shell providing structural strength and a plastic or polymer inner core providing weight reduction. This hybrid material approach maintains the necessary mechanical strength for lace tensioning while significantly reducing the overall weight compared to fully metal construction, thereby resolving the contradiction between strength and weight.
Solution Approach 2:
The patent segments the knob into distinct functional parts: a metal shell for structural integrity and strength, and a plastic or polymer inner core for weight reduction and cushioning. This segmentation allows each material to perform its optimal function, achieving both strength and weight reduction that would be impossible with a single material.
3Device complexity
If a simple fastening mechanism with a case and spring is used, then the structure is simple, but the lace is easily released and requires re-tying
Solution Approach 1:
The patent changes the fundamental operating parameter from spring-based elastic recovery to friction-based static resistance. By using a knob that applies continuous friction pressure to the lace, the system achieves reliable fastening security while maintaining structural simplicity, as the friction mechanism is inherently more stable than spring-based systems that require precise tension control.
Solution Approach 2:
The patent employs a simple friction-based knob mechanism that is easier and cheaper to manufacture than precision spring assemblies. The knob can be made from composite materials or simple mechanical components, providing reliable fastening without the complexity and cost of precision spring mechanisms, thereby resolving the contradiction between simplicity and reliability.
4Adaptability or versatility
If a buckle with metal components is used to adjust lace length and tightness, then the adjustment capability is achieved, but the structure becomes complex and expensive
Solution Approach 1:
The patent simplifies the adjustment mechanism by using a knob that rotates to change the friction pressure applied to the lace. This parameter-based adjustment (rotational position controlling friction force) provides versatile lace length and tightness adjustment while maintaining structural simplicity, as the knob mechanism is easier to manufacture than complex metal buckle assemblies.
Solution Approach 2:
The patent uses composite materials in the knob construction, combining metal shell and plastic or polymer core, which reduces manufacturing complexity and cost compared to fully metal buckles. This composite approach maintains the necessary adjustability while simplifying the overall structure and reducing expenses.
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 device provides secure and adjustable lace tensioning with reduced weight and cost, resisting external forces and vibrations, and ensures the lace is safely contained within the device.
Implementation Method 1
Through the interference between components inside the buckle, the length of the lace as well as the tightness can be adjusted
Implementation Method 2
The knob includes a main body made of a composite material, and a shield cover covering on the main body and made of a metal material
Data Source
AI summary
A fastening device includes a case unit including a receiving space, a spool located within the receiving space and configured for a lace to be wound therearound, and a knob covering on the case unit. The knob includes a main body made of a composite material, and a shield cover covering on the main body and made of a metal material. A rotation of the knob drives the spool to rotate in a tightening direction for tensioning the lace.