Articulation Joint Centering Mechanism for Precise Surgical Control
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Solution Overview
Problem
Existing surgical instrument adapters face challenges in accurately controlling articulation mechanisms with multiple axes, leading to unpredictable movement and position variation during actuation, which affects the precision and stability of surgical procedures.
Innovation Solution
A joint assembly with a proximal and distal joint mechanism, featuring a biasing mechanism with inner and outer biasing bars, and a center pin and shaft pin system, that maintains alignment until the distal joint reaches its articulation limit, allowing controlled articulation and precise movement of the tool assembly relative to the longitudinal axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple universal joints are used to provide omnidirectional articulation, then accessibility to surgical site is improved, but articulation control precision deteriorates due to simultaneous multi-axis movement
Solution Approach 1:
The articulation mechanism is segmented into a proximal joint and a distal joint that are decoupled through a gimbal mechanism. The proximal joint handles articulation in one plane while the distal joint handles articulation in another plane, preventing simultaneous multi-axis movement and improving articulation control precision while maintaining omnidirectional capability.
Solution Approach 2:
A gimbal mechanism acts as an intermediary between the proximal and distal joints. This gimbal decouples the two joints, allowing each to articulate independently about its own axis without causing simultaneous movement in multiple axes, thereby resolving the contradiction between articulation range and control precision.
2Adaptability or versatility
If multiple universal joints are used for omnidirectional articulation, then articulation flexibility is improved, but position stability deteriorates due to position variation during actuation
Solution Approach 1:
The joint system is divided into separately controllable proximal and distal joints with independent articulation axes. This segmentation allows each joint to maintain stable positioning independently while still providing flexible omnidirectional articulation capability when needed.
Solution Approach 2:
The gimbal serves as a mediator that isolates the proximal and distal joints from each other. This isolation prevents position variation and instability that would occur if the joints were coupled, while still allowing the system to achieve flexible articulation through coordinated movement of the two independent joints.
3Ease of operation
If force is applied to articulate the end effector, then articulation movement is achieved, but position control accuracy deteriorates due to simultaneous multi-axis articulation
Solution Approach 1:
The articulation mechanism is segmented into independent proximal and distal joints that rotate about orthogonal axes. When force is applied to one joint, it articulates only about its own axis without causing simultaneous movement in the other joint, thereby maintaining position control accuracy while achieving ease of articulation movement.
Solution Approach 2:
The gimbal acts as an intermediary that decouples the force transmission between joints. Force applied to articulate one joint does not translate to simultaneous articulation of the other joint, preserving position control accuracy while maintaining operational ease.
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 predictable and stable articulation of surgical instruments, minimizing chatter and maintaining precise control during surgical procedures by ensuring the joint assembly remains aligned until the maximum articulation angle is reached, thereby enhancing surgical precision and reducing mechanical backlash.
Implementation Method 1
The biasing mechanism is engaged with the first ring and the joint cover to bias the joint cover towards an aligned configuration in which the cover axis is aligned with the first longitudinal axis
Data Source
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AI summary
A joint assembly of an adapter defines a first longitudinal axis and includes first and second hinges, first and second rings, a joint cover, and a biasing mechanism. The joint cover has first and second cover portions. The first ring is pivotally coupled to the first hinge and the first cover portion is pivotally coupled to the first hinge to define a first joint center. The second ring is pivotally coupled to the second cover portion and the second hinge is pivotally coupled to the second ring to define a second joint center that is spaced from the first joint center. The first and second joint centers define a cover axis of the joint cover. The biasing mechanism is engaged with the first ring and the joint cover to bias the joint cover towards an aligned configuration in which the cover axis is aligned with the first longitudinal axis.