Flexible-Bladder Joint Assembly for Constant Internal Volume
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Solution Overview
Problem
Extravehicular activity (EVA) suits face challenges due to changing joint volumes as they are articulated, requiring significant user effort and limited oxygen resources, leading to increased time and fuel consumption for space missions.
Innovation Solution
A joint assembly with a tubular body and flexible bladder arrangement that maintains a constant internal volume during articulation, using a non-gaseous fluid and reinforcing fibers to prevent expansion or rupture, and includes self-healing properties to ensure reliability in vacuum environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional joint portions are used in EVA suits, then the joints can be articulated, but the volume inside the joint changes during articulation requiring significant user effort and energy
Solution Approach 1:
The patent employs a pneumatic bladder system filled with gas that expands and contracts to compensate for volume changes during joint articulation. When the joint bends, the bladder volume changes to offset the volume reduction, and when the joint straightens, the bladder expands to restore volume, thereby maintaining constant total volume and reducing the work required against pressure differential
Solution Approach 2:
The patent changes the physical state of the compensating medium from liquid to gas. The gaseous nature of the bladder allows for greater compressibility and volume adjustment range, enabling more effective compensation of volume changes during articulation. The gas pressure within the bladder dynamically adjusts to maintain overall constant volume, reducing the energy required for joint movement
2Quantity of substance
If the EVA suit is pressurised at low pressure (3-4 PSI) to reduce oxygen consumption, then oxygen resources are conserved, but the user still experiences limited mobility and time in the suit
Solution Approach 1:
The pneumatic bladder system allows the EVA suit to be pressurized to lower pressures (3-4 PSI) while maintaining effective joint articulation. The bladder compensates for volume changes during movement, eliminating the need for high pressurization. This enables oxygen conservation through reduced pressure while preserving full joint mobility and user comfort
3Device complexity
If conventional joints are used, then the EVA suit structure is simple, but the changing volume requires significant work and energy from the user
Solution Approach 1:
The patent uses flexible bladder structures made of thin film materials that can expand and contract to compensate for volume changes. These flexible shells are integrated into the joint structure, providing automatic volume compensation through their elastic deformation during articulation, thereby reducing energy requirements without adding significant structural complexity
Solution Approach 2:
The pneumatic bladder system provides automatic volume compensation through pressure-equalization mechanisms. The gas-filled bladder dynamically adjusts its volume in response to joint articulation, maintaining constant total volume without requiring active control systems or complex mechanical components, thus balancing simplicity with energy 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
Reduces the effort required to maneuver joints, allowing extended use in EVA suits and minimizing oxygen resource usage, thus reducing mission duration and fuel consumption.
Implementation Method 1
The significant pressure difference means that changing the volume within the EVA suit takes significant work and energy
Implementation Method 2
The membrane comprises a plurality of reinforcing fibres arranged to prevent the membrane from expanding or stretching
Implementation Method 3
a non-gaseous fluid which moves within the chamber during articulation of the tubular body from said first state to said second state
Data Source
AI summary
The present disclosure relates to a joint assembly configured to define a tubular body having a first end, a second end and a passage therebetween. The tubular body is configured for articulation between a first state in which the first end and second end are in a first orientation with respect to one another, and a second state in which the first end and second end are in a second orientation with respect to one another. The body comprises a flexible bladder arranged between opposing supports, each of the bladder and the supports being ring-shaped so as to define an aperture, the respective apertures forming part of the passage. The bladder defines a chamber, and the chamber is partially filled with a fluid which moves within the chamber during articulation of the tubular body from said first state to said second state in order to maintain a constant internal volume of the joint assembly.