Jointed Link Structures with Preferential Bending for Surgical Instruments
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Solution Overview
Problem
Existing jointed link structures used in minimally invasive surgical instruments face challenges in controlled bending and steering, particularly in small, tortuous paths, due to underconstrained configurations that result in unpredictable movement and larger bend radii, necessitating improved mechanical designs for precise manipulation.
Innovation Solution
A jointed link structure with differing resistances to bending at various link pairs, achieved through the use of tension members and varying protrusion profiles or spring constants, allowing preferential bending at specific locations along the structure, enabling controlled articulation and reduced overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If jointed link structures use underconstrained configurations with fewer force transmission elements, then the overall size of the device is reduced, but the movement and articulation of the links becomes unpredictable and uncontrollable
Solution Approach 1:
The patent applies local quality by providing different protrusion profiles at different link pairs along the kinematic chain. Specifically, distal link pairs have protrusions with smaller radii of curvature that create larger moment arms, while proximal link pairs have protrusions with larger radii of curvature. This local differentiation creates varying resistances to bending at different locations, enabling predictable articulation patterns in an underconstrained structure with fewer force transmission elements than links.
2Adaptability or versatility
If jointed link structures are designed to bend with small radii of curvature to navigate tortuous paths, then accessibility to target sites is improved, but the device requires larger size to accommodate the bending mechanisms
Solution Approach 1:
The patent changes the geometric parameters of the link protrusions along the kinematic chain. By progressively decreasing the radius of curvature of protrusions from proximal to distal link pairs, the structure creates varying moment arms that enable small radii of curvature bending at distal sections while maintaining overall structural integrity. This parameter gradient allows the device to navigate tortuous paths with small bend radii without requiring a proportionally larger overall device size.
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 enables more precise and controlled bending of surgical instruments, allowing them to navigate complex paths with smaller radii of curvature, increasing accessibility to target sites while maintaining a compact design, thereby enhancing the range of minimally invasive surgical procedures.
Implementation Method 1
the first pair of links comprise opposing link faces having first protrusions in rolling contact with one another
Implementation Method 2
a tension member coupled to the first pair of links and the second pair of links, wherein altering tension in the tension member exerts a force tending to articulate the first pair of links and the second pair of links
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
In accordance with various exemplary embodiments of the present teachings, a surgical device can include a first pair of articulably coupled links, a second pair of articulably coupled links, and a tension member coupled to the first pair of links and the second pair of links such that altering tension in the tension member exerts a force tending to articulate the first pair of links and the second pair of links so as to bend the first pair of links and the second pair of links. The surgical device can be configured such that the first pair of links has a lower resistance to bending than the second pair of links upon altering the tension in the tension member.