Prosthetic Foot Floating Forefoot Keel Lateral Rotation
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Solution Overview
Problem
Existing prosthetic feet lack natural ankle rotation, particularly in lateral movement, which is essential for navigating uneven terrain and participating in athletic activities, and often constrain rotation in unnatural or discrete increments.
Innovation Solution
A prosthetic foot design that incorporates flexible and resilient bumpers and springs allowing inversion/eversion (side-to-side) and heel/toe rotation, with adjustable stiffness, enabling a more natural ankle rotation and energy return similar to a human foot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unitary foot design is used, then structural simplicity is maintained, but lateral roll-over movement capability is lost
Solution Approach 1:
The prosthetic foot is divided into multiple independent components: a heel section, a forefoot section, and a midfoot section. These segments are connected through resilient elements that allow relative movement. The forefoot section can rotate laterally relative to the heel section, enabling natural roll-over motion while maintaining overall structural integrity through the segmented design.
2Ease of operation
If joints allowing plantar-dorsiflexion and lateral flexion are incorporated, then ankle movement simulation is improved, but lateral rotation capability is still constrained
Solution Approach 1:
The connection between foot sections is made dynamic through resilient elements rather than fixed joints. The forefoot section can rotate laterally relative to the heel section through a defined range of motion, allowing continuous adjustment rather than discrete increments. This dynamic connection enables natural lateral rotation during athletic activities while maintaining stability during normal walking.
3Adaptability or versatility
If resilient elements are added to enable lateral rotation, then natural ankle rotation is achieved, but device complexity increases
Solution Approach 1:
Resilient elements in the form of flexible bushings or foam structures are incorporated between the heel section and forefoot section. These flexible elements allow lateral rotation and absorption of impact forces while maintaining a relatively simple overall structure. The resilient materials provide the necessary compliance and rotation capability without requiring complex mechanical joints or multiple rigid components.
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
The design provides a soft feel and natural ankle rotation, enhancing mobility on varied terrain and during athletic activities by allowing smooth lateral and longitudinal movements, improving the user's overall gait and comfort.
Implementation Method 1
a resilient element positioned at least partially within the gap, the resilient element configured generally to dissipate stress in the first plate and control deflection between the first plate and the mounting block
Implementation Method 2
replacing the entire foot with an energy storage element such as a spring. As the user steps onto the foot, the user's weight compresses the spring. As the user moves forward, the user's weight comes off the foot and the energy stored in the spring is used to propel the user forward
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 2d~5
AI summary
A prosthetic foot device (10-l0e) has an elongate forefoot spring (42, 42e) carried by a fastener (26-26c, 132) and suspended between upper and lower bumpers (34, 34d, 34e and 38, 38d, 38e). A heel spring (54, 54e) is suspended between an end of the fastener and the lower bumper.