Pendulum-Actuated Prosthetic Ankle Joint for Slope Adaptation
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Solution Overview
Problem
Conventional orthotic and prosthetic ankle joints fail to accurately replicate natural ankle movement, particularly on slopes, leading to insufficient dorsiflexion or excessive pressure, which can cause discomfort and increased risk of falling.
Innovation Solution
An adjustable orthotic or prosthetic ankle joint with a tibial section and talus portion, featuring a pivotally connected shell and an adjustment mechanism that includes a pendulum and lock system, allowing automatic realignment of the ankle joint to mimic natural movement on uneven terrain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed dorsi-stop is provided in the orthotic or prosthetic joint, then the foot dorsiflexion is limited to prevent collapse, but on upward slopes the brace allows insufficient dorsiflexion causing excessive pressure and pain on the proximal section
Solution Approach 1:
The patent applies a dynamic adjustment mechanism that allows the dorsi-stop angle to change automatically in response to slope variations. The adjustment mechanism includes a pendulum that swings with gravity to trigger locking pins that engage with teeth at different angles, enabling the foot-ankle portion to dynamically adapt its dorsiflexion limit based on the terrain slope, thus resolving the contradiction between fixed stability and adaptive versatility.
2Stability of the object's composition
If a plantar flexion stop is provided to prevent excessive foot movement, then the foot and ankle are constrained, but the knee must flex which is fatiguing and may increase falling risk
Solution Approach 1:
The patent implements a dynamic plantar flexion stop mechanism that adjusts the locking angle based on slope conditions. On downward slopes, the mechanism allows greater plantar flexion before engagement, preventing excessive knee flexion and reducing fatigue. The pendulum-based adjustment system automatically modifies the stop angle to maintain knee extension and reduce falling risk while still providing necessary foot movement control.
3Device complexity
If the ankle joint is fixed in a single alignment, then the structure is simple and stable, but it cannot accommodate movement on slopes requiring alignment changes
Solution Approach 1:
The patent segments the ankle joint into multiple functional components: a tibial section, a foot-ankle portion, and an intermediate adjustment mechanism with pendulum, locking pins, and teeth. This segmentation allows each component to perform a specific function while collectively providing slope accommodation. The modular design maintains relative structural simplicity while enabling alignment adjustment through the coordinated interaction of discrete elements.
4Device complexity
If the orthotic or prosthetic device uses a rigid connection between foot and tibia, then the device is structurally simple, but it cannot replicate natural ankle movement on uneven terrain
Solution Approach 1:
The patent replaces the rigid connection with a dynamic articulated joint that includes a pendulum-based adjustment mechanism. The pendulum swings with gravity to automatically adjust the locking angle, allowing the foot-ankle portion to pivot relative to the tibial section in a manner that replicates natural ankle movement on slopes. This dynamic connection maintains structural simplicity while significantly improving the reliability of natural movement replication.
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 secure and natural ankle movement on slopes by automatically adjusting the ankle joint alignment, reducing pressure and fatigue, and enhancing stability and control for users with paralysis or amputations.
Implementation Method 1
an adjustment mechanism that includes a pendulum and lock system, allowing automatic realignment of the ankle joint to mimic natural movement on uneven terrain
Data Source
AI summary
The present disclosure relates to an orthotic (or brace) and/or prosthetic ankle joint and associated methods adapted to enable adjustment of a talus section or ankle portion or brace with respect to a tibial section of the orthotic (or brace) and/or prosthetic ankle joint. The talus section or ankle portion of the orthotic (or brace) and/or prosthetic ankle joint is movably coupled to the tibial section with the alignment between the talus section and tibial section being adjustable between various positions by disengagement or engagement of a lock of an adjustment mechanism. As the lock is disengaged, the talus section is enabled to pivot with respect to the tibial section in at least one direction as the user moves along a slope.