Medical Device Control Handle Multiplying Linear Motion
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Solution Overview
Problem
Existing control handles for medical devices, such as electrophysiology catheters, face limitations in providing sufficient 'throw' or degree of travel for puller wires, requiring multiple wires for bi-directional deflection and additional control, which complicates the design and increases size, especially in confined medical environments.
Innovation Solution
A control handle with a multiplying linear motion actuator assembly that uses first and second knobs and arms to increase the travel distance of a puller member relative to the knobs, allowing greater adjustability of the distal assembly through a housing with incline cam portions and pulley mechanisms, thereby enhancing the 'throw' without expanding the handle's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple puller wires are used for bi-directional deflection and additional control, then control capability is improved, but device complexity and size increase
Solution Approach 1:
The control handle is designed to provide multiplied linear motion throw for multiple puller wires through a compact mechanism. The housing with incline cam portions and arms enables greater travel distance for each puller wire actuation, allowing bi-directional deflection and contraction control within a single integrated handle structure, thus providing multi-functionality without proportionally increasing complexity
2Adaptability or versatility
If multiple puller wires are used for bi-directional deflection and additional control, then control capability is improved, but the size of the control handle increases
Solution Approach 1:
The actuator assembly components including arms, incline cams, and puller wire anchoring regions are nested within the control handle housing in a compact arrangement. The mechanism allows multiple actuation functions to be contained within the same housing volume, providing greater control capability without proportionally increasing the external dimensions of the control handle
3Adaptability or versatility
If the travel distance of puller wire is increased relative to actuator travel, then adjustability of distal assembly is improved, but the mechanism complexity increases
Solution Approach 1:
The housing includes incline cam portions with curved surfaces that convert the linear motion of the actuator into multiplied linear motion of the puller wire. As the actuator moves linearly, the arms ride along the inclined cam surfaces, which are positioned and angled to provide a mechanical advantage, thereby increasing the travel distance of the puller wire relative to the actuator travel without requiring complex rotational or multi-stage mechanisms
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 greater control and adjustability of medical device components, enabling more precise manipulation within limited spaces, such as the heart, by multiplying the linear travel of the puller member, facilitating bi-directional deflection and contraction of the catheter's distal assembly.
Implementation Method 1
The actuator assembly includes a body to which a proximal end of the puller member is fixed, first and second knobs, and first and second arms extending therebetween to link movement of the knobs to the body. The housing is configured with first and second opposing incline cam portions that jointly act on the arms to transfer longitudinal movement of the knobs to the body in a manner that multiplies the travel of the body and hence the puller member relative to the travel of the knobs.
Data Source
Figure 1
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Figure 2B
AI summary
A catheter for use in a patient's heart, especially for mapping a tubular region of the heart, has a catheter body, a deflectable intermediate section and a distal a mapping assembly that has a generally circular portion adapted to sit on or in a tubular region of the heart. A control handle of the catheter allows for deflection of the catheter via a first and second puller wire responsive to a deflection assembly and manipulation of distal assembly via a third puller wire responsive to a linear motion actuator assembly. The linear motion actuator assembly includes a pair of user interface knobs, a body to which a proximal end of the third puller wire anchored, and a pair of arms that movably suspends the body and transmits longitudinal travel of the knobs to the body in a manner that multiples the travel of the body relative to the travel of the knobs.