Shoe Insert Stiffening Area for Power Transmission
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Solution Overview
Problem
Existing shoe inserts fail to effectively address power loss during sports activities due to medial turning of the foot, particularly in cycling, ice skating, cross-country skiing, and rowing, as they do not adequately counteract pronation and distribute force efficiently across the foot.
Innovation Solution
A shoe insert with a continuous stiffening area extending from the longitudinal arch to the forefoot, arched towards the sole, which depresses under pronation to lift the forefoot, distributing pressure and improving power transmission by preventing medial turning and enhancing leverage across the metatarsal heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the foot is allowed to pronate naturally to cushion shock loads, then comfort is improved, but power transmission is reduced due to torsion and medial turning
Solution Approach 1:
The patent converts the harmful pronation movement into a beneficial lever mechanism. The arched stiffening area is positioned to be depressed by pronation forces, which triggers a lifting action at the forefoot through the lever arm formed by the stiffening area extension. This transforms the energy that would otherwise be lost to torsion into useful leverage for power transmission to the pedal.
2Loss of energy
If a stiffening area is added to prevent pronation and improve power transmission, then power transmission is improved, but the insole requires more space in the shoe
Solution Approach 1:
The stiffening area is designed with a specific three-dimensional configuration featuring an arch in the longitudinal direction. This arch allows the stiffening area to be depressed vertically when the foot pronates, which then translates into a lifting motion at the forefoot through the lever arm. This dimensional design enables the stiffening area to function as both a structural support and a dynamic lever mechanism without requiring excessive thickness or volume.
Solution Approach 2:
The stiffening area is implemented as a thin, flexible structure that can be depressed by pronation forces while maintaining its structural integrity. The material and design allow it to flex and deform under load, enabling the lever action without requiring a thick or bulky construction. This thin-film approach minimizes the space required in the shoe while maintaining the necessary mechanical functionality.
3Loss of energy
If the stiffening area extends under all metatarsal heads to distribute force, then power transmission is improved, but the metatarsophalangeal joint of the big toe is constrained
Solution Approach 1:
The stiffening area is designed with non-uniform distribution, being absent specifically under the metatarsophalangeal joint of the big toe while extending under the other metatarsal heads. This local modification allows the big toe joint to maintain its natural mobility and rolling motion during the gait cycle, while the stiffening area under the other metatarsal heads provides the necessary force distribution and lever action for power transmission.
4Object-affected harmful factors
If existing shoe inserts are used to support the arch, then comfort is improved, but power transmission loss between talus and toe joints is not prevented
Solution Approach 1:
The insole is segmented into distinct functional areas: a soft support area for comfort, an arched stiffening area for lever action, and a gap area under the big toe joint for mobility. The stiffening area itself is segmented to extend specifically from the longitudinal arch to below certain metatarsal heads, creating the necessary lever arm while leaving other areas flexible. This segmentation allows each region to perform its specific function without interfering with others.
Data Source
Figure 1a~1b
Figure 2~3
AI summary
A shoe insole comprising a continuous stiffening area that includes at least one area of the shoe insole which, when the foot is in contact with the insole, extends substantially from the longitudinal arch to the forefoot, wherein, when the foot is in contact with the insole, the stiffening area is curved against the sole of the foot in the area of the longitudinal arch, and, in the unloaded state, the areas of the shoe insole which, when the foot is in contact with the insole, are located in the area of the hindfoot and forefoot, lie substantially in the zero plane, and the stiffening area is further designed such that, when the foot is in contact with the insole, at least the area of the metatarsophalangeal joint of the big toe is located outside the stiffening area.