Knee Rotational Adapter with Automatic Locking Mechanism
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Solution Overview
Problem
Conventional prosthetic knee joints for above-the-knee amputees only allow for flexion and extension, restricting the ability to rotate the lower portion of the prosthesis about its longitudinal axis, which limits mobility and stability during walking and prevents activities like sitting cross-legged, posing safety risks due to unstable alignment.
Innovation Solution
A knee rotational adapter that allows selective rotation of the lower portion relative to the upper portion while maintaining stability during walking, featuring a locking mechanism to prevent unwanted rotation, ensuring secure attachment to both the upper and lower prosthetic components and incorporating a release mechanism for adjustable alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional single-axis prosthetic knees are used, then the knee joint provides stable flexion and extension during walking, but the lower portion cannot rotate about its longitudinal axis, limiting mobility and preventing activities like sitting cross-legged
Solution Approach 1:
The prosthetic knee joint transitions from a fixed single-axis design to a dynamic multi-axis system that can adapt its degrees of freedom based on operational needs. The adapter mechanism allows the lower portion to rotate about the longitudinal axis when unlocked, while automatically locking during walking to maintain stability, thus providing dynamic adaptability between mobility and stability states
Solution Approach 2:
An adapter mechanism is introduced as an intermediary component between the upper and lower portions of the prosthetic limb. This adapter serves as a mediator that enables rotational movement when needed while maintaining the original flexion-extension functionality, thus resolving the contradiction between adding rotational capability and preserving alignment stability
2Adaptability or versatility
If the lower portion is allowed to rotate about its longitudinal axis during walking, then mobility and activities like sitting cross-legged are enabled, but the prosthetic foot may twist out of proper alignment creating unsafe conditions
Solution Approach 1:
The adapter mechanism incorporates an automatic locking feature that activates during walking based on the natural loading conditions. The system self-regulates by locking the rotational degree of freedom when weight-bearing occurs, eliminating the need for external control while preventing the harmful twisting effect on the prosthetic foot
Solution Approach 2:
The locking mechanism is designed to preemptively prevent rotational movement during walking by automatically engaging the lock before twisting can occur. This preliminary anti-action counteracts the potential harmful effect of rotation during weight-bearing activities while preserving rotational freedom during non-weight-bearing periods
Data Source
AI summary
A prosthetic adapter including a lower connector, an upper connector rotatably coupled to the lower connector, and a locking mechanism for preventing the upper connector from rotating relative to the lower connector. The locking mechanism is arranged to generally automatically retain a locked position when the lower connector is rotated to an original, predetermined alignment. An activation member is connected to and arranged for operating the locking mechanism.