Walking Assist Device Shank Link Knee Mechanism
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Solution Overview
Problem
Conventional crutches restrict hand use, require excessive energy, and can cause axillary pressure and nerve damage due to their design, while alternative devices like the iWALKFree impose an awkward leg position and instability.
Innovation Solution
A walking assist device with a shank link and thigh member connected at a knee mechanism that resists motion during stance to prevent foot contact and reduces ground reaction force, featuring adjustable components and a torque generator for controlled resistance, allowing a more natural gait and reduced energy expenditure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crutches are used to support body weight, then the injured leg is bypassed, but the user's hands are restricted and excessive energy is required
Solution Approach 1:
The invention extracts the hand-holding function from the weight support function. The crutch is designed with a handless mechanism where the underarm pad and structural components provide weight support without requiring the user to grip or hold the crutch, thereby freeing the hands for other tasks while maintaining reliable weight bearing capability
Solution Approach 2:
The crutch components serve multiple functions: the underarm pad provides both structural support and weight bearing, the handless design simultaneously achieves weight support and hand freedom, and the overall device provides both mobility assistance and hand liberation without requiring separate mechanisms
2Reliability
If conventional crutches are used to transfer body weight, then the injured leg is protected, but energy consumption doubles
Solution Approach 1:
The crutch design allows the user's natural body movements and gait pattern to drive the weight transfer mechanism, rather than requiring active manipulation or additional muscular effort. The passive mechanical structure converts the user's existing motion into effective weight bearing, reducing the additional energy expenditure typically required to operate crutches
3Reliability
If conventional crutches are used for weight bearing, then the injured leg is bypassed, but axillary pressure and nerve damage occur
Solution Approach 1:
The underarm pad is designed with optimized local properties including appropriate padding material, distributed pressure surface area, and ergonomic shaping that concentrates support forces on the broader shoulder region rather than focal points on the axilla, thereby maintaining effective weight bearing while minimizing localized pressure damage and nerve compression
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
Enables hands-free walking with reduced energy consumption and minimized pressure on the axillary region, providing stability and comfort by mimicking leg movement and distributing forces effectively.
Implementation Method 1
a torque generator configured to produce the controlled resistance
Implementation Method 2
a compliant element coupled between the shank link and the artificial foot
Data Source
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AI summary
A walking assist device, which is to be worn on a person's leg, includes a shank link, a thigh member, and a knee mechanism. The thigh member is in contact with the person's thigh when the device is worn on the person's leg. The knee mechanism rotatably connects the shank link to the thigh member. When the shank link is in contact with the ground, the knee mechanism is configured to resist the rotation of the shank link relative to the thigh member to prevent the person's foot from contacting the ground and reduces ground reaction forces entering the person's foot.