Flexible Device Shaft With Angled Spiral Wrap Nesting
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Solution Overview
Problem
Conventional minimally invasive medical devices, such as catheters and endoscopes, face challenges with flexibility due to the use of metal or plastic spiral wraps, where the surface edges of adjacent wraps touching lead to axial elongation and reduced flexibility, interfering with accurate anatomical tracking.
Innovation Solution
The implementation of beveled edges on the spiral wraps allows for nesting of adjacent wraps, reducing axial elongation and increasing flexibility while maintaining column strength, by enabling the wraps to cooperate and nest within each other during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plastic spiral wraps are used with greater wall thickness and tighter spacing to provide comparable crush and kink resistance, then crush and kink resistance is improved, but shaft flexibility deteriorates due to surface edges touching and pushing wraps away from each other
Solution Approach 1:
The patent applies nesting by configuring the spiral wrap edges such that adjacent wraps nest within each other during bending. The leading edge of one wrap is received within the trailing edge of the adjacent wrap, allowing the wraps to cooperate and eliminate the pushing-away effect that causes axial elongation. This nesting configuration maintains crush and kink resistance while restoring shaft flexibility.
2Strength
If metal spiral wraps are used, then shaft column strength is improved, but manufacturing cost increases and further processing becomes difficult due to poor substrate properties
Solution Approach 1:
The patent changes the material parameter from metal to plastic for the spiral wrap. By modifying the edge geometry parameters (creating complementary nesting edges) and adjusting the wrap configuration, the patent achieves comparable mechanical performance with plastic material, thereby reducing manufacturing cost and improving processability while maintaining necessary structural strength.
Data Source
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AI summary
Spiral-wound materials, spirals, and shafts made therefrom that have wraps with edges that may nest within one another are described. Such edges allow the spiral to achieve a smaller bending radius, meaning tighter turns and more flexibility due to the ability of adjacent wraps to nest within each other when the shaft is bent. Spirals having wraps with edges capable of nesting can be used in the medical field for devices that track anatomy, such as endoscopes, colonoscopes, catheters, and the like.