Pivot-Flex Prosthetic Foot With Coupling Mechanism
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Solution Overview
Problem
Amputees experience pain and musculoskeletal issues due to shear stress and transverse-plane torque from conventional prosthetic feet, which lack rotation in the transverse plane, leading to compensatory gait patterns and skin problems like epidermoid cysts and osteoarthritis.
Innovation Solution
A prosthetic device with a coupling mechanism that allows rotation of the foot component between the sagittal and transverse planes, mimicking natural foot movement, reducing transverse-plane torque and improving gait symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional prosthetic feet with rigid pylon connection are used, then structural stability is maintained, but transverse-plane torque is transmitted to the residual limb causing skin problems and pain
Solution Approach 1:
The prosthetic foot is divided into multiple segments that can rotate relative to each other about different axes. The foot assembly includes a heel assembly, midfoot assembly, and toe assembly that can independently rotate, allowing transverse-plane motion without transmitting torque to the residual limb while maintaining structural integrity through controlled segmentation.
Solution Approach 2:
The prosthetic foot transitions from a rigid structure to a dynamic multi-axis rotation system. The coupling mechanism enables the foot to adapt its orientation in real-time during gait cycles, providing sagittal-plane rotation for forward motion and transverse-plane rotation for directional changes, thereby eliminating harmful torque transmission.
2Ease of manufacture
If conventional prosthetic feet allowing only sagittal-plane rotation are used, then manufacturing simplicity is maintained, but natural gait patterns cannot be replicated leading to compensatory movements
Solution Approach 1:
The prosthetic foot incorporates dynamic multi-axis rotation capabilities through a coupling mechanism that connects sagittal-plane and transverse-plane motion. This allows the foot to naturally adapt to gait requirements without complex control systems, replicating human foot behavior while maintaining reasonable manufacturing complexity through mechanical coupling.
Solution Approach 2:
The prosthetic foot assembly is designed to perform multiple functions: sagittal-plane rotation for forward propulsion, transverse-plane rotation for directional changes, and automatic coupling between these motions. This multi-functionality replicates natural foot behavior across various gait conditions without requiring separate mechanisms for each function.
3Adaptability or versatility
If transverse rotation adapters are added to prosthetic pylons, then transverse-plane rotation is increased, but device complexity increases and dynamic stability may be reduced
Solution Approach 1:
The transverse rotation capability is merged directly into the foot assembly structure rather than being added as a separate adapter component. The coupling mechanism within the foot assembly integrates sagittal and transverse rotation functions, eliminating the need for additional transverse rotation adapters and reducing overall system complexity.
Data Source
AI summary
A prosthetic device is provided including (a) an ankle component, (b) a foot component coupled to the ankle component, wherein the foot component has a longitudinal length extending at least partially along a sagittal plane of a user when the prosthetic device is in use, wherein the foot component has a thickness extending at least partially along a transverse plane of a user when the prosthetic device is in use, and (c) a coupling mechanism positioned between the foot component and the ankle component, wherein the coupling mechanism couples a rotation of the foot component with respect to the sagittal plane to a rotation of the foot component with respect to the transverse plane.