Variable Stiffness Endoscope Shaft Spiral Wrap Design
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Solution Overview
Problem
Single-use endoscopes and catheters require cost-effective manufacturing while maintaining performance characteristics equivalent to reusable devices, which is challenging due to the high expense of materials and manufacturing processes for variable stiffness shafts.
Innovation Solution
A shaft with a spiral wrap that varies flexibility along its length by modifying gap spacing, wrap width, and thickness, and material, allowing for adjustable stiffness sections to enhance flexibility and column strength, specifically in the distal section for steering and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable stiffness shafts are made using traditional methods (varying outer sheath material or braid characteristics), then flexibility and column strength are improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by varying the gap spacing between spiral wrap coils at different locations along the shaft. The distal section has larger gap spacing for enhanced flexibility, while the proximal section has smaller gap spacing for greater column strength. This localized structural variation achieves the required performance characteristics without expensive materials or complex manufacturing processes.
Solution Approach 2:
The patent changes the geometric parameter of gap spacing between spiral wrap coils to control shaft stiffness. By adjusting this parameter along the shaft length, the device achieves variable flexibility and column strength characteristics, providing an inexpensive alternative to varying material properties.
2Ease of operation
If the distal section is made highly flexible for steering, then navigability is improved, but column strength decreases
Solution Approach 1:
The patent implements local quality by creating distinct structural characteristics in different sections of the shaft. The distal section features larger gap spacing between spiral wrap coils to enable flexible steering and navigation, while the proximal section has smaller gap spacing to provide the column strength needed to transmit forces from the operator.
Solution Approach 2:
The shaft is segmented into functional zones with different flexibility requirements. The spiral wrap structure is configured with varying gap spacing to create distinct proximal and distal sections, each optimized for its specific function while maintaining overall structural integrity.
Data Source
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AI summary
A shaft for a medical device includes an outer sheath and a flexible spiral wrap therein. The flexibility of the spiral wrap is modified by changing the width of the wraps of a spiral, the thickness of the wraps of a spiral, or the gap spacing of the spiral. The spacing between wraps is maintained by attaching the spiral wrap to the cover sheath that surrounds the spiral wrap at two or more locations.