Catheter Contact Force Spring With Mechanical Stops Against Overstretch
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Solution Overview
Problem
Catheters experience irreversible deformation due to high tensile forces when used with assemblies like balloons, leading to potential damage and failure of the contact force spring.
Innovation Solution
Incorporating helical cuts with deviations and mechanical stops in the spring design to prevent overbending and overstretching, allowing simultaneous engagement of stops to share the load and prevent sequential failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spring is made more flexible to accommodate high tensile forces, then the catheter can better withstand stress, but the spring becomes susceptible to irreversible deformation and failure
Solution Approach 1:
Mechanical stops are pre-positioned within the helical cuts at specific locations along the spring. These stops are prepared in advance to engage when the spring reaches predetermined deformation limits, preventing further deformation before irreversible damage can occur. The stops are strategically placed to activate at critical stress points during catheter insertion and use.
Solution Approach 2:
The mechanical stops act as pre-positioned protective elements that cushion the spring against excessive tensile forces. When the spring encounters high stress during catheter navigation, the stops engage to absorb and distribute the force, preventing the spring from undergoing deformation beyond its elastic limit. This protective mechanism is already in place before the damaging forces are applied.
2Adaptability or versatility
If the spring is designed with multiple helical cuts to improve flexibility, then the catheter can navigate complex pathways, but the spring becomes more prone to sequential failure under high stress
Solution Approach 1:
Mechanical stops are pre-positioned within each helical cut at specific locations along the spring. These stops are prepared in advance to engage when the spring reaches predetermined deformation limits, preventing further deformation before irreversible damage can occur. The stops are strategically placed to activate at critical stress points during catheter insertion and use.
Solution Approach 2:
The mechanical stops act as pre-positioned protective elements that cushion the spring against excessive tensile forces. When the spring encounters high stress during catheter navigation, the stops engage to absorb and distribute the force, preventing the spring from undergoing deformation beyond its elastic limit. This protective mechanism is already in place before the damaging forces are applied.
3Ease of manufacture
If the spring uses conventional helical cuts without deviations, then the manufacturing is simpler, but the spring cannot prevent overbending and overstretching under high tensile forces
Solution Approach 1:
The helical cuts are designed with localized deviations at specific positions along the spring, rather than being uniform throughout. These local deviations create discrete mechanical stops at critical locations where the spring is most susceptible to overbending or overstretching. The majority of the helical cut remains simple and continuous, maintaining ease of manufacture, while the localized deviations provide the necessary protective function.
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 design effectively prevents irreversible deformation of the spring, ensuring reliable force measurement and functionality even under high stress conditions.
Implementation Method 1
a spring including a tube with at least one helical cut extending around a circumference of the tube, the at least one helical cut including deviations extending in a longitudinal direction of the tube
Data Source
AI summary
A catheter apparatus, including an elongated deflectable element, a distal assembly, a force sensor disposed between the elongated deflectable element and the distal assembly, and comprising a spring including a tube with at least one helical cut extending around a circumference of the tube, the at least one helical cut including deviations extending in a longitudinal direction of the tube, the deviations being configured to prevent overstretching and overbending of the spring.