Catheter Layer Bonding via Interlocking Protrusions
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Solution Overview
Problem
Existing catheters and balloon catheters face issues where the outer layer readily comes off the inner layer when pulled, especially in curved ducts like blood vessels or bile ducts, due to stress concentration at the bonding points, leading to a weakened bond and potential detachment.
Innovation Solution
The catheter design incorporates a reinforcing layer with gaps where the inner layer protrudes to engage with the outer layer, creating a strengthened bond across a larger area and anchoring effect, with a flexible second outer layer on the distal end for enhanced engagement and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a reinforcing layer is interposed between an inner layer and an outer layer to bond these layers, then the catheter structure is strengthened, but the bond between the inner layer and the outer layer becomes difficult to strengthen
Solution Approach 1:
The invention transitions from planar bonding to three-dimensional interlocking bonding. Protruding portions extend in the axial direction to stick into the outer layer, creating engagement along the length of the catheter rather than at a single plane. This dimensional change transforms the bonding mechanism from surface adhesion to volumetric interlocking, significantly enhancing bond strength and reliability.
Solution Approach 2:
The protruding portions are configured with curved surfaces that follow the wavy contour of the reinforcing layer. This curvature allows the bonding interface to conform to the natural undulations of the reinforcing layer, increasing the contact area and distributing stresses more evenly across the bonding interface, thereby preventing delamination.
2Area of stationary object
If only irregularities are provided on the outer circumference of the inner layer and on the inner circumference of the outer layer, then the bonding area is increased, but the outer layer readily comes off the inner layer when pulled in the distal end direction
Solution Approach 1:
The reinforcing layer is segmented into discrete wound wires with gaps between adjacent wires. This segmentation allows protruding portions to pass through the gaps and engage the outer layer at multiple discrete points along the axial direction. The segmented structure transforms continuous bonding into multi-point anchoring, providing superior resistance to axial pulling forces while maintaining adequate bonding area.
Solution Approach 2:
The bonding mechanism extends from radial engagement (irregularities on circumferential surfaces) to axial engagement (protruding portions sticking into the outer layer). This dimensional extension creates a three-dimensional interlocking structure where protruding portions anchored in the inner layer and extending axially provide mechanical interlocking that resists delamination under axial loading conditions.
3Adaptability or versatility
If a catheter is inserted into a curving duct causing the catheter to bend, then the catheter can navigate complex anatomy, but stress concentrates at the bonding portion between outer layer and inner layer causing potential detachment
Solution Approach 1:
The bonding structure is designed with locally optimized features: protruding portions are strategically positioned and dimensioned to provide enhanced anchoring at critical locations. The wavy contour and protruding portions create localized stress distribution patterns that prevent stress concentration at any single bonding point, thereby maintaining bonding reliability under bending conditions while preserving catheter flexibility for navigating curving ducts.
4Volume of moving object
If the outer layer is pulled in the radial direction outwardly, then the catheter can expand to treat stenosis, but the outer layer readily comes off the inner layer
Solution Approach 1:
The wavy contour and curved protruding portions are designed to accommodate radial expansion. When the catheter expands, the curved bonding interface allows for controlled deformation without creating stress concentration points that would cause delamination. The geometric configuration of the bonding features absorbs expansion stresses through elastic deformation of the curved surfaces, maintaining bond integrity during radial expansion for stenosis treatment.
Data Source
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AI summary
[Problems to be Solved] An object of the present invention is to provide a catheter and a balloon catheter in which an outer layer does not readily come off an inner layer when the outer layer is pulled in the axial direction (in the distal end direction and in the proximal end direction) or in the radial direction (outwardly). [Solution] In a catheter 1, in a gap 25 of a reinforcing layer (coil body) 30, disposed is a first bonding portion 50 where a first inner layer protruding portion 12 of an inner layer 10 sticking into a first outer layer 40 is engaged with a first outer layer protruding portion 42 of the first outer layer 40 sticking into the inner layer 10. This configuration enlarges the area across which the first outer layer 40 and the inner layer 10 are bonded to each other within the gap 25 of the reinforcing layer (coil body) 30, leading to a strengthened bond between the first outer layer 40 and the inner layer 10. The first bonding portion 50 is anchored in the reinforcing layer (coil body) 30 to produce an anchoring effect, which can reduce the probability of the first outer layer 40 to come off the inner layer 10 when the catheter 1 bends to cause the first outer layer 40 to be pulled in the axial direction (in the distal end direction and in the proximal end direction).