Vacuum Pump with Spring-Loaded Movable Wall for Prosthetic Socket
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Solution Overview
Problem
Existing vacuum-assisted suspension systems in prosthetics face challenges in maintaining consistent negative air pressure due to inconsistent compressive force during gait, leading to inefficient use of the vacuum pump and air leakage.
Innovation Solution
A method and system that utilize a compression transfer element to increase and decrease the volume of a fluid chamber within the vacuum pump, ensuring complete fluid expulsion and reduction in air pressure fluctuations, with a movable wall and spring element to optimize each pump cycle, and a one-way valve to maintain vacuum within the socket.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vacuum pump relies on complete compression to expel air in each cycle, then the pump capacity is maximized, but complete compression cannot occur consistently due to variable impact and displacement during gait
Solution Approach 1:
The invention introduces a spring element that dynamically adjusts the compression force applied to the piston. The spring provides a restoring force that ensures complete compression of the fluid chamber regardless of variations in external impact and displacement during gait, maintaining consistent pump operation and reliable vacuum creation.
Solution Approach 2:
The spring element changes the mechanical parameter of compression force, transforming variable impact forces into consistent compressive action on the piston. This parameter transformation ensures that the fluid chamber is completely compressed in every cycle, maximizing pump capacity while maintaining reliability despite gait variations.
2Ease of operation
If the seal covering the socket brims is used to create vacuum space, then suspension is achieved, but air leakage occurs through the non-airtight seal
Solution Approach 1:
The invention extracts the vacuum creation function from the passive seal structure and relocates it to an active pump system. The pump actively removes air from the socket space, maintaining vacuum pressure regardless of seal imperfections, thereby resolving the contradiction between ease of attachment and reliable vacuum maintenance.
Solution Approach 2:
The pump system creates a feedback mechanism where air leakage is continuously counteracted by active pumping. The system monitors vacuum pressure indirectly through the pump's operation, automatically compensating for air ingress through the seal, thus maintaining reliable suspension despite non-airtight sealing.
3Productivity
If the fluid chamber volume increases during compression, then fluid is drawn in from the socket space, but without complete expulsion the vacuum efficiency decreases
Solution Approach 1:
The spring element provides dynamic restoration force that ensures complete compression of the fluid chamber in every cycle. This dynamic mechanism guarantees that all fluid drawn into the chamber is fully expelled, maximizing vacuum creation efficiency while preventing energy waste from incomplete pumping cycles.
Solution Approach 2:
The spring ensures continuous and complete compression action, maintaining uninterrupted vacuum creation. By guaranteeing full expulsion of fluid in every cycle, the system maintains continuous useful action without energy-wasting incomplete cycles, improving overall productivity and efficiency.
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
This solution enhances the efficiency of the vacuum pump by fully utilizing each cycle, reducing air pressure fluctuations, and providing a more consistent and effective attachment between the prosthetic socket and residual limb, improving blood flow, wound healing, and proprioception.
Implementation Method 1
a spring element that is compressed by the movable wall upon application of a compressive force and configured to expand in the absence of force on the movable wall to assist in expelling fluid out of the fluid compartment
Implementation Method 2
A compression transfer element is connected between a prosthetic foot and the vacuum pump. The compression transfer element causes the movable wall to reciprocate within the housing upon application of a compressive force to the prosthetic foot
Implementation Method 3
fluid is drawn into the fluid chamber from a socket space or cavity through an input port upon an increase in the volume of the fluid chamber
Data Source
AI summary
A vacuum assisted suspension system is used to increase or maintain negative pressure or vacuum in a sealed socket cavity as a socket and prosthetic limb attachment mechanism. The system includes a vacuum pump (2) having a housing (8) that defines an enclosed space to receive a fluid. At least one wall of the housing (8) and at least one movable wall (10) define a fluid compartment (12). The system includes a compression transfer element (15) connected to the at least one movable wall (10) and connected to a prosthetic foot (6). The compression transfer element (15) causes the at least one movable wall (10) of the fluid compartment (12) to move and increase the volume of the fluid compartment (12) in response to a compressive force on the prosthetic foot (6) to draw in fluid from the prosthetic socket (4). In the absence of a compressive force, the volume of the fluid compartment (12) decreases thereby expelling fluid out of the fluid compartment (12).