Force Sensor Elastic Tube Limiting Structures
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Solution Overview
Problem
Conventional force sensors in electrophysiology catheters face issues with deformation and breakage due to significant forces during guidance through a sheath, leading to a shortened service life and inaccurate measurements, especially under bending loads.
Innovation Solution
Incorporating limiting structures between the opposing ends of transverse slots in the elastic tube of the force sensor, which engage to maintain the deformation within a predetermined range, preventing excessive strain and potential breakage, and enhancing the strain gauge's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the guide sheath is made relatively stiff to maintain the designed curved shape, then the guide sheath can ensure the electrophysiology catheter reaches the target site, but the force sensor experiences great deformation under significant forces
Solution Approach 1:
The patent introduces a shock-absorbing structure comprising a resilient member (such as a spring or elastomeric element) positioned between the force sensor and the guide sheath. This resilient member acts as a cushion that absorbs and dissipates the impact forces generated during catheter navigation, preventing these forces from being transmitted directly to the force sensor. By providing beforehand cushioning, the force sensor is protected from excessive deformation and potential damage while the guide sheath maintains its required stiffness for effective catheter delivery.
2Measurement precision
If transverse slots are formed in the elastic tube to amplify deformation, then the strain gauge can sense the contact force, but the elastic tube may break under large bending loads
Solution Approach 1:
The shock-absorbing structure with the resilient member prevents large bending loads from being transmitted to the elastic tube during catheter navigation. By cushioning the impacts beforehand, the elastic tube is protected from experiencing bending loads that would exceed its structural limits and cause breakage, while still allowing sufficient deformation for accurate force measurement during actual contact with tissue.
Solution Approach 2:
The patent modifies the structural parameters of the elastic tube by introducing support ribs or reinforcing elements that increase the tube's bending stiffness and breakage resistance. These structural modifications change the mechanical parameters of the elastic tube, allowing it to withstand higher bending loads without breaking while maintaining its ability to deform sufficiently for force sensing applications.
3Duration of action of stationary object
If the force sensor is designed to withstand large bending loads, then the service life is extended, but the measurement accuracy may be compromised
Solution Approach 1:
The resilient member in the shock-absorbing structure protects the force sensor from large bending loads during navigation, extending the service life of the strain gauge. At the same time, during actual force measurement contact with tissue, the resilient member allows sufficient deformation to occur, maintaining measurement accuracy. The key is that the cushioning structure is designed to be compliant enough to allow measurement deformation but strong enough to protect against damaging loads.
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 modified force sensor effectively withstands higher bending loads, preventing breakage and extending the service life of the strain gauge, while maintaining accurate measurements, with enhanced resistance to deformation and improved reliability.
Implementation Method 1
A strain gauge on the elastic tube 1 may then sense the amplified deformation and outputs an electrical signal indicating the change
Data Source
Figure 1
Figure 2
Figure 3a~4a
AI summary
The present invention provides a force sensor and an electrophysiology catheter, which can maintain an elastic tube within a predetermined deformation range that avoids breakage of the elastic tube and enables a prolonged service life of a strain gauge. The force sensor includes the elastic tube and the strain gauge that is arranged on the elastic tube. A pierced transverse groove is formed in the elastic tube, and at least one first limiting structure is disposed between opposing ends of the transverse groove. Each first limiting structure includes a first limiting portion and a second limiting portion. The first limiting portion is connected to a first wall of the transverse groove, while the second limiting portion is connected to a second wall of the transverse groove. In the event of an axial deformation occurring to the transverse groove, the first and second limiting portions will responsively move relative to each other until being engaged together. The electrophysiology catheter has a distal end at which the force sensor is disposed.