Lace Fastening Spool With Pawl Lock Against Vibration Loosening
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Solution Overview
Problem
Existing fastening devices for laces, such as those used in shoes, face issues with security due to easy loosening from external forces and vibrations, and have complex structures that increase manufacturing costs and assembly difficulties.
Innovation Solution
A fastening device comprising a base, spool, knob, engaging unit, spiral track, and retaining portions, where the engaging unit can switch positions to secure or release the spool, utilizing a pawl arm mechanism to prevent rotation and allow for adjustable lace tension, with the retaining portions designed to deform under external forces for secure positioning.
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 deteriorates because the lace is easily loosened due to vibrations or external forces
Solution Approach 1:
The fastening mechanism is divided into distinct functional components: a pawl arm for one-way engagement, inner teeth on the spool for meshing, and retaining portions for positional stability. This segmentation allows each component to perform its specific function effectively, maintaining reliability while keeping the overall structure simple.
Solution Approach 2:
Instead of using a spring to actively hold the lace tight, the invention uses a pawl-arm mechanism that passively prevents loosening by allowing rotation in one direction (tightening) while blocking rotation in the opposite direction (loosening). This inversion of the active/passive role resolves the contradiction between simplicity and reliability.
2Reliability
If a complex rotating buckle with interference components is used, then the reliability is improved by securing the lace inside, but the device complexity increases leading to higher manufacturing cost and assembly difficulty
Solution Approach 1:
The invention extracts and eliminates the complex rotating buckle structure and its interference components from the design. Instead, it uses a simplified spool with pawl-arm engagement that achieves the same security function without the unnecessary complexity, directly addressing the contradiction between reliability and device complexity.
Solution Approach 2:
The patent employs simple, easily manufacturable components such as the pawl arm and inner teeth that can be produced through basic molding or machining processes. These components are designed to be functional and secure without requiring complex assembly or expensive materials, resolving the contradiction between reliability and manufacturing complexity.
3Ease of operation
If the engaging unit is designed to switch positions for tightening and releasing, then the ease of operation is improved, but the device complexity increases due to additional components like spiral track and guiding portion
Solution Approach 1:
The pawl arm is integrated directly with the engaging unit, and the retaining portions are coupled to either the knob or base, merging multiple functions into fewer components. This integration reduces the overall device complexity while maintaining the ease of operation for tightening and releasing the lace.
Solution Approach 2:
The pawl arm automatically engages with the inner teeth when the spool is rotated in the tightening direction, and the retaining portions self-lock into position on the spiral track. This self-service mechanism eliminates the need for additional actuators or complex control systems, resolving the contradiction between ease of operation and device complexity.
Data Source
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Figure 2B
AI summary
A fastening device (100, 110, 120) includes a base (200, 200a, 200b), a spool (300, 300a, 300b), a knob (500, 500a, 500b), an engaging unit (400, 400a, 400b) and at least one deforming portion (410, 410a, 410b, 420, 420a, 420b, 430b). The spool is disposed at the base, and a lace ( is wound around the spool. The knob is disposed at the base. The engaging unit is disposed at the base. The at least one deforming portion is coupled to the base or the knob. The engaging unit has a first position and a second position relative to the knob. The engaging unit prohibits the spool from rotating toward a releasing direction (A1) when the engaging unit is at the first position, and the engaging unit allows the spool to be rotated toward the releasing direction when the knob is rotated toward the releasing direction and the at least one deforming portion is deformed to allow the engaging unit to switch to the second position.