Prosthetic Foot Pump Mechanism for Vacuum Suspension
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Solution Overview
Problem
Existing prosthetic devices face challenges in securely attaching to the residual limb due to uneven pressure distribution, leading to discomfort, sores, and instability during walking.
Innovation Solution
A prosthetic system that utilizes a pump mechanism integrated into the prosthetic foot, which generates negative pressure inside the socket through the expansion and compression of the foot member, creating a vacuum without bulky components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical pump is used to generate vacuum in the socket, then negative pressure can be applied to secure attachment, but the pump relies on complete compression before decompression which makes vacuum generation unpredictable and inadequate
Solution Approach 1:
The patent inverts the conventional pump operation sequence by eliminating the compression step entirely. Instead of compressing then decompressing to generate vacuum, the pump mechanism directly expands during the user's walking motion to create negative pressure, reversing the traditional approach and achieving reliable vacuum generation without compression.
Solution Approach 2:
The pump mechanism is designed to automatically generate vacuum during the user's natural walking motion without requiring manual operation or external power sources. The pump's expansion is driven by the user's own movement, making the system self-actuating and eliminating the need for complex control systems.
2Reliability
If the pump is integrated into the prosthetic limb, then vacuum suspension is achieved, but the pump becomes bulky and significantly increases the weight of the prosthetic limb
Solution Approach 1:
The pump mechanism utilizes a flexible diaphragm or membrane that can expand and contract to generate vacuum. This flexible film approach replaces bulky rigid pump components with a thin, lightweight flexible structure that achieves the same vacuum generation function while dramatically reducing weight and volume.
Solution Approach 2:
The patent extracts the essential vacuum-generating function from complex mechanical pump components and isolates it into a simple expandable chamber with a flexible membrane. By removing unnecessary structural elements and focusing only on the core expansion-compression function, the design achieves lightweight vacuum suspension.
3Productivity
If conventional pumps are used, then vacuum can be generated, but the pumps are bulky and significantly contribute to the weight burden on the user
Solution Approach 1:
The patent changes the operational parameters of the pump by eliminating the compression phase and relying solely on expansion during user movement. This parameter change allows the use of lighter materials and simpler structures while maintaining effective vacuum generation capability throughout the gait cycle.
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 system provides a secure and reliable vacuum suspension, reducing sliding movement between the liner and socket, and maintaining suction over time, while being lightweight and streamlined.
Implementation Method 1
generating negative pressure inside a prosthetic socket worn over a residual limb
Implementation Method 2
The weight placed on the foot member of the prosthetic foot expands and compresses the foot member, which, in turn, expands a pump mechanism that efficiently draws air out from the socket
Data Source
AI summary
A prosthetic system includes a prosthetic foot having an upper foot element with a concave-forward facing portion and foot portion extending forwardly therefrom. An intermediate foot element is disposed below the upper foot element and has a front portion coupled to the foot portion of the upper foot element. A lower foot element is disposed below the intermediate foot element. A pump system is coupled to the prosthetic foot and comprises a pump mechanism including a housing defining a cavity, and a membrane situated in the cavity. The pump mechanism is movable between an original configuration and an expanded configuration. An arm member is connected to the pump mechanism and operatively coupled to the intermediate foot element. The arm member is arranged to move the pump mechanism toward at least the expanded configuration upon movement of the intermediate foot element relative to the upper foot element.