Sports Shoe Closure Lever With Strain Wave Gear Tightening
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Solution Overview
Problem
Existing sports shoes face challenges in achieving optimal closure of flaps due to morphological foot diversity, with existing mechanisms requiring multiple turns or inadequate string take-up, especially when using circular levers or strain wave gears.
Innovation Solution
A sports shoe design incorporating a lever with a circular winding device based on strain wave gears, allowing for rapid and simple tightening by leveraging a transmission ratio between 1:6 and 1:30, optimizing flap closure based on individual foot shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If circular levers with spools are used to take up string, then the string can be taken up by the desired amount, but the user must apply a high number of turns to the spool
Solution Approach 1:
A gear mechanism is introduced as an intermediary between the spool and the user's manual operation. The gear system with multiple toothed wheels (first toothed wheel, second toothed wheel, third toothed wheel) and corresponding gear teeth creates a mechanical advantage, allowing the spool to rotate multiple times for each turn of the adjustment mechanism, thereby reducing the number of turns the user must apply while maintaining precise string take-up control
Solution Approach 2:
The invention changes the operational parameter from direct spool rotation to gear-mediated rotation. By introducing a gear train with specific tooth counts (e.g., 30 teeth on first wheel, 20 teeth on second wheel, 10 teeth on third wheel), the system transforms the user's input motion into amplified spool rotation, effectively changing how the take-up amount is achieved while maintaining precision
2Adaptability or versatility
If multiple circular levers are used to accommodate different foot morphologies, then adaptability improves, but the number of turns required increases
Solution Approach 1:
The gear-based lever mechanism serves multiple functions: it can accommodate different foot morphologies (adaptability) while simultaneously reducing the number of turns required (time efficiency). The universal gear design with multiple toothed wheels allows the same mechanism to handle various string lengths and take-up requirements across different shoe models and user needs, eliminating the need for multiple specialized levers
3Device complexity
If levers with fixed tooth spacing are used, then the structure is simple, but the closing optimization for diverse foot shapes is insufficient
Solution Approach 1:
The lever system transitions from a fixed, static structure to a dynamic, adjustable mechanism. The gear train allows the effective tooth spacing to be varied through different gear combinations and rotation ratios, enabling the lever to adapt to diverse foot shapes and flap closing requirements while maintaining a relatively simple base structure of interconnected toothed wheels
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 design enables rapid and precise adjustment of flap closure, accommodating various foot sizes with minimal user effort, providing excellent closure and adjustment based on morphological foot shape.
Implementation Method 1
the rotation of the externally toothed gearing is thus increased to a speed ratio that corresponds to the difference in the number of teeth between the externally toothed gear and the internally toothed gear on the transmission side
Implementation Method 2
a deformation wave, because it represents a wave deflection in one of the elements of the gear set
Data Source
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AI summary
A sports shoe (1) comprising an upper or a shell (2), to which at least one bootleg (3) is articulated, which wrap around the foot and optionally part of the leg of the user and have a first and a second flap (4, 5) which can be closed; the sports shoe comprises at least one lever (6), associated with the upper or shell (2), to which at the least one bootleg (3) is articulated, which is adapted to take up at least one string (7) associated with, and therefore guided on, the first and the second flap (4, 5) and/or upper or shell (2), to which the at least one bootleg (3) is articulated; Such string (7) is keyed on a circular winding device based on strain wave gears (8).