Catheter Flat Beam Deflection Tip With Fiber Puller Ferrules
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Solution Overview
Problem
Existing catheters with metal puller wires for bi-directional deflection are prone to breakage and costly, while fiber-based puller members offer a smoother feel and higher pull force, but securely anchoring them to a metal deflection beam is challenging.
Innovation Solution
A catheter design using a metal deflection beam with fiber puller members anchored by crimped ferrules, where the ferrules are shaped to lie flat against the beam and resistance or laser welded, allowing secure attachment without debris or contaminants, enabling predictable on-plane bi-directional deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal puller wires are used for bi-directional deflection, then the catheter structure is simple and易于 manufacture, but the puller wires are prone to breakage and costly
Solution Approach 1:
A ferrule is introduced as an intermediary component between the fiber puller member and the metal deflection beam. The ferrule provides a secure anchoring point for the fiber and a suitable surface for welding to the metal beam, solving the compatibility issue between non-metallic fiber and metallic beam while ensuring reliable force transmission for bi-directional deflection.
Solution Approach 2:
The catheter employs a composite construction combining fiber-based puller members with metal ferrules and a metal deflection beam. This composite approach leverages the high strength-to-weight ratio and flexibility of fibers while utilizing the structural integrity and weldability of metal components, achieving both reliability and manufacturability.
2Ease of operation
If fiber-based puller members are used, then the catheter provides smoother feel and higher pull force, but securely anchoring them to metal deflection beam is challenging
Solution Approach 1:
The ferrule serves as a mediator that bridges the fiber puller member and metal deflection beam. It provides a crimping interface for the fiber and a welding interface for the metal beam, enabling secure anchoring while maintaining the operational advantages of fiber-based puller members including smooth deflection feel and high pull force capacity.
Solution Approach 2:
The ferrule undergoes plastic deformation through crimping to change its geometric parameters, creating a mechanical interlock with the fiber puller member. This parameter change enables secure anchoring of the fiber without requiring complex chemical bonding or specialized joining techniques.
3Reliability
If metal ferrule is crimped onto fiber puller member, then secure anchoring is achieved, but the ferrule may contain debris or contaminants affecting weld quality
Solution Approach 1:
The ferrule is functionally segmented into two distinct zones: a proximal crimping zone for securing the fiber puller member and a distal welding zone for attachment to the metal deflection beam. This segmentation isolates the welding area from contaminants introduced during crimping, ensuring high weld quality while maintaining secure fiber anchoring.
Solution Approach 2:
The potential source of contamination (crimping debris) is effectively extracted or isolated from the welding zone by the spatial separation provided by the ferrule's geometry. The crimping action occurs in the proximal portion while the welding occurs at the distal portion, preventing debris from interfering with weld quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a robust and cost-effective catheter with smooth bi-directional deflection capabilities, reducing the risk of breakage and enhancing maneuverability within the patient's vessel.
Implementation Method 1
a metal ferrule that is crimped onto a distal end of the fiber puller member
Implementation Method 2
the thin planar distal portion is resistance or laser welded to the beam
Implementation Method 3
the thin planar distal portion is resistance or laser welded to the beam
Data Source
AI summary
A catheter has a metal deflection beam with rectangular cross-section and one or two fiber puller members for predictable on-plane bi-directional deflection. Each fiber puller member is anchored at its distal end to a respective surface of the beam by a metal ferrule that is crimped onto the distal end. The ferrule is shaped to provide a flat outer underside that can lie flat against a beam surface and a thin planar distal section that is welded to the beam. With a distal end of the beam sandwiched between the thin planar distal section of two ferrules, the ferrules and the beam can be welded together by a single laser pulse.