Blood Pressure Cuff Airbag Stress Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional airbags for blood pressure measuring devices suffer from stress concentration and reduced durability at constricted portions, leading to potential rupture and decreased longevity due to inadequate reinforcement techniques.
Innovation Solution
The airbag design incorporates a main sheet member with constricted portions formed by welding, paired with sub sheet members that occupy a wider region and are welded at center near portions, distributing stress and enhancing durability by alleviating concentration at regions of high deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constricted portions are formed by welding opposed inner walls of the airbag to create projecting portions for uniform pressure distribution, then the cuff fixation is improved, but stress concentration occurs at the welded portions leading to reduced durability and potential rupture
Solution Approach 1:
The patent applies composite materials by combining the airbag main body (formed from flexible resin sheets) with reinforcing members (rigid rods or beams) at the constricted portions. This composite structure allows the airbag to maintain its flexibility while the reinforcing members provide the necessary strength and stress distribution capability, preventing rupture at the welded constricted portions while preserving the cuff fixation function.
Solution Approach 2:
The patent implements local quality by placing reinforcing members specifically at the constricted portions where stress concentration occurs, rather than uniformly throughout the entire airbag. The reinforcing members are positioned locally at the constricted portions to provide targeted strength enhancement where needed, while the rest of the airbag maintains its original flexible properties for effective inflation and cuff fixation.
2Ease of manufacture
If conventional welding techniques are used to form constricted portions, then manufacturing is simplified, but the welded portions experience thickness decrease and strength reduction
Solution Approach 1:
The patent uses composite materials to compensate for the strength reduction at welded portions. The reinforcing members (rigid rods or beams) are integrated with the airbag at the constricted portions to make up for the thickness decrease and strength reduction caused by welding, thereby maintaining overall structural strength while keeping the manufacturing process simple.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating reinforcing members at the constricted portions before the airbag is inflated and subjected to stress. These reinforcing members act as a preventive measure against potential rupture at the welded portions, cushioning against the stress concentration that would otherwise occur during normal operation.
3Productivity
If the airbag is inflated to fix the cuff, then blood pressure measurement function is achieved, but fatigue accumulates at constricted portions reducing service life
Solution Approach 1:
The patent applies composite materials by combining the flexible airbag structure with rigid reinforcing members at the constricted portions. This composite construction allows the airbag to undergo repeated inflation and deflation cycles for blood pressure measurement while the reinforcing members prevent fatigue accumulation and rupture, thereby extending the service life of the airbag.
Solution Approach 2:
The patent implements beforehand cushioning by positioning reinforcing members at the constricted portions before the airbag is put into service. These reinforcing members provide continuous protection against fatigue during repeated use, cushioning against the stress cycles that would otherwise lead to rupture and ending the service life of the airbag.
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 configuration significantly enhances the strength and durability of the airbag, reducing fatigue and maintaining performance comparable to conventional airbags while potentially using lower-strength materials, thus lowering manufacturing costs and weight.
Implementation Method 1
the pair of sub sheet members are respectively welded to the corresponding layers of the main sheet member at a portion corresponding to the constricted portion
Data Source
AI summary
An airbag for a blood pressure measuring device for fixing a cuff, including: a main sheet member which spreads in two layers forming a bag body, wherein a constricted portion is formed on the bag body, the constricted portion narrowing the air chamber with respect to the width direction, a pair of sub sheet members are disposed so as to correspond to the respective layers of the main sheet member, the sub sheet member occupying a region including at least a portion corresponding to the constricted portion, and the pair are respectively welded to the layers of the main sheet member at the constricted portion, the pair being welded to the corresponding layers of the main sheet member at a center near portion away from the constricted portion toward a center side with respect to the width direction.