Enclosed Lace Fastener With Directional Spool Locking
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Solution Overview
Problem
Existing fastening mechanisms for laces are prone to loosening due to external forces, have complex structures, and increase manufacturing costs, while also exposing the lace, posing safety risks.
Innovation Solution
A fastening device comprising a case, spool, knob, and locking unit that allows for secure fastening and loosening of laces through a simplified structure, using a knob rotation mechanism to engage and disengage the spool, ensuring the lace is retained without complex components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple spring-based fastening mechanism is used, then the device complexity is reduced, but the reliability of fastening deteriorates as the lace is easily released due to vibrations or external force
Solution Approach 1:
The locking unit dynamically changes state between locked and unlocked positions based on the rotation direction of the knob. The pawl arm engages with the gear teeth to lock the spool in the tightening direction, while allowing free rotation in the loosening direction, providing directional control and reliable fastening without complex components
Solution Approach 2:
The pawl arm acts as an intermediary mechanism between the knob rotation and the spool locking. It translates the rotational motion of the knob into selective engagement with the gear teeth, enabling reliable one-way locking while maintaining a simple overall structure
2Reliability
If a complex buckle structure with interference components is used, then the reliability of fastening is improved, but the device complexity increases and manufacturing cost rises
Solution Approach 1:
The fastening device is segmented into distinct functional components: the spool for lace winding, the locking unit with pawl arm and gear teeth for secure locking, and the knob for operation. This segmentation allows each component to perform its specific function efficiently while keeping the overall structure simple and manufacturable
Solution Approach 2:
The locking unit automatically engages and disengages based on the direction of knob rotation without requiring additional control mechanisms. The pawl arm self-activates to lock the spool when the lace is tightened and allows free rotation when loosening is needed, eliminating the need for complex control systems
3Device complexity
If a spring-based fastening mechanism is used, then the device complexity is reduced, but the ease of operation deteriorates as the lace exposure may bring danger
Solution Approach 1:
The spool is nested within the housing, and the locking unit is nested within the same housing space. The lace is wound around the spool and secured inside the compact assembly, preventing exposure and eliminating safety hazards while maintaining a simple structural design
4Reliability
If a rotational buckle mechanism is used, then the reliability of fastening is improved, but the ease of manufacture deteriorates due to complex structure
Solution Approach 1:
The locking mechanism uses simple gear teeth and a pawl arm that can be easily replicated through standard manufacturing processes. The modular design allows for easy copying and mass production, reducing manufacturing costs while maintaining reliable fastening functionality
Data Source
AI summary
A fastening device is provided. The fastening device includes a case, a spool, a knob and a locking unit. When the knob is rotated relative to the case in a tightening direction, the spool is not affected by the locking unit and is allowed to rotate in the tightening direction for fastening the lace. When the knob is rotated relative to the case in a loosening direction, the spool is allowed to freely rotate in the loosening direction to release the lace. As the knob is engaged with the housing via an engagement between the mounted portion and the engaged portion, the housing, the locking unit, the knob and the spool are combined and restricted.