Endoscope Covering Rubber Hardness Gradient for Sterilization Stability
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Solution Overview
Problem
Endoscopes with flexible insertion portions face challenges in maintaining a secure fixation of the covering rubber around the bending portion, particularly during high-temperature high-pressure steam sterilization, where the rubber is subjected to deformation and pressure differences, leading to adhesive peeling and instability.
Innovation Solution
The endoscope design incorporates a covering rubber with varying hardness levels, where the end portions are tightly bound to rigid portions using threads and adhesives, with the end portions having a higher hardness than the center portion to enhance durability and prevent peeling during sterilization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the covering rubber is tightly bound to the rigid portion using threads and adhesives, then the fixation is secured, but the adhesive peels during high-temperature high-pressure steam sterilization
Solution Approach 1:
The covering rubber is designed with different hardness levels in different regions: the end portions have higher hardness (70-90 durometer) while the center portion has lower hardness (30-60 durometer). This local quality differentiation allows the end portions to maintain stable bonding with adhesives during sterilization, while the center remains flexible for bending operations.
Solution Approach 2:
The patent changes the physical parameter of hardness within the covering rubber material. By creating a hardness gradient from the center to the ends, the material properties are optimized to resist adhesive peeling at the bonded end portions while maintaining flexibility in the center portion for bending operations.
2Adaptability or versatility
If the covering rubber has high flexibility for bending operations, then the endoscope can navigate body cavities, but the adhesive bonding becomes unstable during sterilization
Solution Approach 1:
The covering rubber exhibits different mechanical properties at different locations: high flexibility in the center portion for bending operations, and high hardness at the end portions for stable adhesive bonding during sterilization processes.
Solution Approach 2:
The covering rubber is functionally segmented into a center portion and end portions, each with different hardness characteristics. The center portion (lower hardness) accommodates bending movements while the end portions (higher hardness) provide stable anchorage for adhesive fixation.
3Reliability
If the end portions of the covering rubber are made harder to prevent peeling, then bonding stability improves, but the overall flexibility of the insertion portion decreases
Solution Approach 1:
The covering rubber is designed with non-uniform hardness distribution, where only the end portions require high hardness for bonding stability, while the center portion maintains low hardness for flexibility. This localized property assignment resolves the contradiction between bonding stability and overall flexibility.
Data Source
AI summary
An endoscope comprising, in a part of an insertion portion having flexibility, a bending portion formed by covering an outermost circumference with a covering rubber. Respective end portions of the covering rubber being tightly bound to a rigid portion near the bending portion with a thread and fixed by applying an adhesive. In at least one end portion of both fixed end portions of the covering rubber, hardness of at least a portion in a range from an end portion in a center portion side of a portion tightly bound with the thread to an end portion in a center portion side of a portion to which the adhesive is applied is set higher than hardness in a center portion of the covering rubber.