Catheter Transition Region Step Design for Breaking Position Stability
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Solution Overview
Problem
Medical catheters with varying diameters face instability in breaking position under external load, either breaking weakly at the distal-end portion with small outer diameter or being prone to breakage at the transition zone without adequate strength.
Innovation Solution
A catheter design featuring a first region with a smaller outer diameter, a second region with a larger outer diameter, and a transition region connecting them, where the transition region's outer diameter gradually decreases and includes a step portion on its surface, enhancing breaking strength and stabilizing the breaking position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a tapered portion is formed over the entire circumference between the main body portion and distal-end portion, then the transition is smooth, but the breaking position becomes unstable and the catheter may break at the distal-end portion with small outer diameter
Solution Approach 1:
The patent applies local quality by providing a step portion only at specific locations on the outer circumferential surface of the transition region, rather than uniformly across the entire surface. This localized modification creates specific stress distribution patterns that stabilize the breaking position while maintaining adequate breaking strength. The step portions are strategically positioned to control where stress concentrates during excessive loading.
2Stability of the object's composition
If only a step portion is provided without a tapered portion, then the breaking position stabilizes, but the distal-end portion with small outer diameter breaks with low breaking strength
Solution Approach 1:
The patent employs asymmetry by combining a generally tapered transition region with localized step portions that create asymmetric stress distribution. The transition region provides gradual diameter change, while the step portions (protrusions or recesses) introduce controlled asymmetries that stabilize the breaking position. This asymmetric design prevents uniform stress distribution that would lead to unpredictable breaking locations.
3Ease of operation
If the catheter has multiple regions with different diameters to increase insertability and strength, then insertability and strength are improved, but the transition region becomes a weak point prone to breakage
Solution Approach 1:
The patent applies preliminary action by pre-designing the transition region with step portions that control stress concentration before excessive loading occurs. The step portions are formed during manufacturing to predetermined positions and dimensions, creating a predetermined breaking pattern that prevents catastrophic failure at unpredictable locations. This preliminary structural design ensures the transition region can withstand normal operational stresses while providing controlled behavior under excessive load.
Data Source
AI summary
A catheter includes a first region having a first outer diameter; a second region having a second outer diameter larger than the first outer diameter; and a transition region connecting with the first region and the second region, the transition region having an outer diameter being equal to or larger than the first outer diameter and equal to or smaller than the second outer diameter, wherein the outer diameter of the transition region gradually decreases from the second region toward the first region, and part of an outer circumferential surface of the transition region is formed in a shape having a step portion.