Articulation Joint Centering Mechanism for Stable Surgical Control
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Solution Overview
Problem
Existing surgical instrument adapters face challenges in accurately controlling the articulation of end effectors due to simultaneous articulation about multiple axes, leading to instability and difficulty in maintaining joint positions during actuation.
Innovation Solution
A joint assembly with a proximal joint housing, hinges, rings, and a biasing mechanism that maintains the joint assembly in an aligned configuration until the distal joint reaches a maximum articulation limit, allowing precise control of articulation angles and reducing chatter during surgical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an articulation joint includes multiple axes of articulation to improve accessibility to surgical site, then the articulation flexibility is improved, but the accuracy of articulation control deteriorates because the end effector is articulated about multiple axes simultaneously
Solution Approach 1:
The joint assembly is divided into separate hinge mechanisms (first hinge and second hinge) with distinct pivot axes. The first hinge provides articulation about a first axis while the second hinge provides articulation about a second axis that is orthogonal to the first axis. This segmentation allows independent control of each articulation axis, resolving the control accuracy problem while maintaining flexibility.
Solution Approach 2:
A joint cover acts as an intermediary component between the first hinge and second hinge. The joint cover is pivotally coupled to the first hinge and also pivotally coupled to the second hinge, mediating the interaction between the two articulation axes. This intermediary structure enables precise control of the articulation angles while maintaining the ability to articulate about multiple axes.
2Adaptability or versatility
If multiple hinges and rings are used to enable articulation about multiple axes, then the articulation versatility is improved, but the device complexity increases
Solution Approach 1:
The first hinge and second hinge are merged into a single integrated joint assembly structure. The joint cover serves as a common component that connects both hinges, allowing them to function together as a unified articulation mechanism. This merging reduces the overall complexity compared to having separate, independent hinge assemblies while maintaining the ability to articulate about multiple axes.
Solution Approach 2:
The joint cover performs multiple functions: it serves as a structural component housing the articulation mechanism, acts as a pivotal connection point for both hinges, and provides a mounting surface for the end effector. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while maintaining articulation versatility.
3Adaptability or versatility
If the joint assembly allows free articulation about multiple axes, then the range of motion is improved, but the stability of joint positions deteriorates during actuation
Solution Approach 1:
The biasing mechanism applies a preliminary counteracting force to the joint assembly to prevent unwanted movement. The biasing mechanism is configured to urge the joint cover toward an aligned configuration, counteracting forces that would cause the joints to shift during actuation. This preliminary anti-action maintains joint position stability while allowing the full range of motion when needed.
Solution Approach 2:
The biasing mechanism changes the force parameters acting on the joint assembly. By applying a controlled biasing force, the mechanism modifies the equilibrium position and stiffness characteristics of the joint assembly. This parameter change allows the joints to maintain stable positions during actuation while still permitting the full range of motion when actuation forces are applied.
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 enhances the accuracy and stability of articulation mechanisms, allowing for predictable articulation of surgical instruments and minimizing chatter, thereby improving the precision and reliability of surgical operations.
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
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.