Rotatable Protective Tube with Stoppers for Guide Wire Protection
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Solution Overview
Problem
Existing medical devices face challenges in treating stenosed sites in blood vessels due to calcification, particularly in bifurcated regions, and generate friction that can lead to guide wire breakage or coating peeling.
Innovation Solution
A medical device with a rotatable tubular drive shaft, a cutting unit, and a protective tubular main body that includes stoppers to prevent axial movement while allowing rotation, thereby protecting the guide wire from excessive friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tube is fixed to the cutting unit and rotates together with it, then the cutting unit can effectively cut stenotic lesions, but friction is generated on the guide wire causing breakage or coating peeling
Solution Approach 1:
The protective tube is separated from the cutting unit, allowing independent movement. The protective tube can rotate independently or remain stationary while the cutting unit rotates, preventing friction transmission to the guide wire while maintaining cutting effectiveness
Solution Approach 2:
The protective tube acts as an intermediary between the guide wire and the rotating cutting unit. It provides a low-friction interface that protects the guide wire from direct contact with rotating components, eliminating the harmful friction effect
2Reliability
If the protective tubular main body is allowed to rotate freely, then friction on the guide wire is reduced, but axial movement control is lost
Solution Approach 1:
The protective tubular main body is designed with dynamic characteristics - it can rotate freely to reduce friction, but axial movement is constrained by stoppers. This selective freedom allows rotational movement for friction reduction while maintaining axial position control through mechanical stops
Data Source
AI summary
A medical device for cutting an object in a body lumen includes: a tubular drive shaft; a cutting unit fixed to a distal portion of the drive shaft; a protective tubular main body accommodated in the drive shaft and the cutting unit and rotatable relative to the drive shaft; and a protective-side stopper disposed on an outer peripheral surface of a distal portion of the protective tubular main body. The distal portion of the drive shaft or the cutting unit has a drive-side stopper contactable with the protective-side stopper. By the protective-side stopper coming into contact with the drive-side stopper, the protective tubular main body is restrained from moving axially with respect to the drive shaft without being restrained from rotating relative to the drive shaft.