Wrist Cuff Air Bladder Layout for Accurate Blood Pressure Sensing
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Solution Overview
Problem
Conventional blood pressure measuring devices, particularly those worn on the wrist, suffer from measurement errors due to insufficient air volume in the air chamber and limited contact area, leading to inaccurate pressure readings and blocked air flow passages.
Innovation Solution
A cuff design with a main air bladder having a larger cross-sectional area than sub air bladders, a stent in the folding portion to prevent passage blockage, and a structured air flow system with branch passages to ensure efficient air distribution, allowing for accurate pressure application on the radial artery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the air chamber is made larger to accommodate more air for accurate pressure measurement, then measurement precision is improved, but the device becomes bulkier and less portable
Solution Approach 1:
The air chamber is divided into multiple air bladders (first air bladder, second air bladder, third air bladder) that can be inflated independently. This segmentation allows the device to maintain a compact overall size while providing sufficient air volume for accurate pressure measurement through coordinated inflation of multiple smaller chambers rather than one large chamber.
Solution Approach 2:
The multiple air bladders are nested within the cuff structure, with the first air bladder positioned at the distal end, second air bladder in the middle, and third air bladder at the proximal end. This nested arrangement maximizes the use of available space within the compact cuff design, allowing sufficient air volume for measurement while maintaining portability.
2Measurement precision
If the air chamber is made larger to improve measurement accuracy, then pressure measurement is improved, but the contact area with the wrist is limited
Solution Approach 1:
The air chamber is segmented into multiple bladders positioned at different locations along the cuff. The first air bladder contacts the distal wrist, second air bladder contacts the middle wrist, and third air bladder contacts the proximal wrist. This segmentation distributes the contact area across multiple regions, ensuring sufficient total contact area for accurate pressure application while maintaining measurement precision.
Solution Approach 2:
Instead of relying on a single large air chamber, the design uses multiple air bladders arranged along the longitudinal dimension of the cuff. This dimensional distribution allows the air bladders to contact the wrist at multiple points along its length, effectively increasing the total contact area without requiring a single large chamber that would compromise portability.
3Volume of moving object
If the flow passage is made foldable to improve portability, then device compactness is improved, but air flow may be blocked
Solution Approach 1:
A flow passage support structure acts as an intermediary element within the foldable flow passage. This support structure prevents the flow passage from collapsing or bending into a blocked state during folding, while still allowing the passage to be compacted for portability. The support structure maintains patentability of the air flow path through the folded configuration.
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 cuff design ensures accurate blood pressure measurement by effectively pressurizing the radial artery with sufficient air pressure and maintaining unobstructed air flow, enhancing measurement precision and portability.
Implementation Method 1
an air supply unit (110) that introduces air into the cuff (100); a pressurizing unit (120) that expands when air is introduced from the air supply unit (110) to pressurize a radial artery located at a wrist of a subject
Implementation Method 2
a pressurizing unit (120) that expands when air is introduced from the air supply unit (110) to pressurize a radial artery located at a wrist of a subject
Data Source
AI summary
A cuff for a blood pressure measuring device includes: an air supply unit comprising an air inlet through which air is introduced from the outside and an air outlet through which air inside is discharged; a pressurizing unit connected to the air supply unit and configured to expand when air is introduced from the air supply unit, and a folding portion disposed between the air supply unit and the pressurizing unit and including a first air passage that connects the air supply unit and the pressurizing unit to communicate with each other. The pressurizing unit includes a main air bladder disposed to contact the wrist and connected to the air supply unit, at least one sub air bladder laminated on one side of the main air bladder, and a communication passage that connects the main air bladder and the sub air bladder to communicate with each other.