Sphygmomanometer Back Plate Non-Uniform Thickness
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Solution Overview
Problem
Conventional sphygmomanometers face challenges in accurately measuring human body pressure pulse waves due to high-pressure distribution caused by welding portions of the sensing cuff, which affects the measurement accuracy by applying pressure differently from the intended measurement area.
Innovation Solution
A sphygmomanometer design featuring a sensing cuff with a back plate that has a width direction dimension shorter than the sensing cuff and further shorter than the inner dimension between welding pools, ensuring that the hard welding portions are not pressed, thereby minimizing stress and achieving uniform pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing cuff is pressed flat against the human body with a back plate, then the stability and measurement capability are improved, but the welding portions and welding pools locally apply high pressure to the human body, generating high-pressure distribution in portions different from where blood pressure information is measured
Solution Approach 1:
The back plate is designed with non-uniform thickness, featuring a thinner portion positioned at the welding pool area and a thicker portion at the center. This local variation in thickness creates differential pressure distribution, allowing the back plate to apply sufficient pressing force at the measurement area while reducing pressure at the welding pool locations, thereby eliminating the harmful high-pressure distribution without compromising overall measurement capability
Solution Approach 2:
The back plate's thickness parameter is strategically varied across different regions. By changing the thickness parameter from uniform to non-uniform distribution, the mechanical properties of the back plate are modified to achieve selective pressure application - maintaining firm contact for accurate measurement while avoiding excessive pressure at welding portions that would interfere with blood pressure detection
2Stability of the object's composition
If the back plate width direction dimension is made larger to enhance sensing cuff stability, then the stability is improved, but the welding pools press the human body more strongly, generating inaccurate pressure distribution
Solution Approach 1:
The back plate employs local quality variation through non-uniform thickness distribution. The wider portions at the edges provide stability support without directly pressing the welding pools, while the thinner central region controls pressure application. This spatially differentiated structure allows the back plate to simultaneously achieve both stability enhancement and accurate pressure distribution for measurement
3Measurement precision
If the sensing cuff is pressed with sufficient force to obtain accurate blood pressure information, then the measurement capability is improved, but the hard welding portions generate strong stress and high pressure distribution in non-measurement areas
Solution Approach 1:
The back plate's thickness parameter is optimized to create a pressure distribution profile that maintains sufficient overall pressing force for accurate blood pressure measurement while locally reducing stress at welding portions. The non-uniform thickness acts as a stress modulation mechanism, allowing the system to achieve measurement capability improvement without proportional increase in harmful stress concentration
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 design allows for accurate measurement of human body pressure pulse waves by avoiding the hard welding portions, resulting in improved measurement accuracy and reduced noise in blood pressure readings.
Implementation Method 1
a back plate disposed on the second sheet, extending along the circumferential direction of the site to be measured, and conveying a pressing force to the sensing cuff
Implementation Method 2
accurate measurement of human body pressure pulse waves by avoiding the hard welding portions
Data Source
AI summary
A sphygmomanometer includes a sensing cuff, and a back plate. The sensing cuff includes a first sheet extending in a circumferential direction of the site to be measured to cross an artery passing portion of the site to be measured, and a second sheet facing the first sheet. The sensing cuff has a bag shape formed by welding the first sheet and the second sheet. The back plate is disposed on the second sheet, extending along the circumferential direction of the site to be measured. A width direction dimension of the back plate measured in a width direction parallel to a direction in which the artery extends, is shorter than a width direction dimension of the sensing cuff, and is further shorter than an inner dimension between welding pools formed at end portions of an internal space of the sensing cuff.