Rolling Joint Pin Coupling for Minimally Invasive Surgery

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Solution Overview

Problem

Existing articulating structures for minimally invasive surgery instruments face issues with smooth steering and precise control due to external forces causing segment separation and reduced stiffness, as well as misalignment of wire passages during bending, which hinders precise control and increases the length of the structure.

Innovation Solution

An articulating structure with rolling contact surfaces and pin coupling, where the pin is inserted into a coupling hole with a larger area, allowing relative position movement and maintaining line contact, enabling smooth and precise steering while minimizing the contact area and dissipating loads, thus preventing segment separation and misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pin coupling is used to fix segments, then segment separation is prevented, but smooth movement is hindered due to loads focused on the pin

Engineering Contradiction:

Improvesegment connection stabilityVSAvoidmovement smoothness

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

A rolling element (roller or ball) is introduced as an intermediary between the pin and the segment contact surfaces. This rolling element mediates the load transmission, allowing the pin to maintain secure connection while the rolling element distributes loads during movement, preventing direct contact between the pin and segment surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional pin-hinge mechanism is replaced with a rolling joint mechanism. Instead of direct mechanical contact and rotation at the pin, the system uses rolling contact between the rolling element and the segment surfaces, substituting the mechanical friction-based hinge action with a lower-friction rolling contact system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If pin coupling serves as a hinge, then segments are connected, but wire passage misalignment occurs during bending

Engineering Contradiction:

Improvesegment connectionVSAvoidwire passage alignment

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The articulating structure is divided into multiple segments connected by rolling joints, with each segment having its own wire passage. The rolling joint design allows each segment to move independently while maintaining proper wire passage alignment through the rolling contact mechanism, preventing the caught wire phenomenon.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wire passage alignment problem is solved by changing the dimensional relationship between segments and wire passages. The rolling joint allows segments to rotate about the rolling element while maintaining parallel wire passage orientations, effectively decoupling the segment rotation from wire passage misalignment.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If gap is formed for pin coupling installation, then pin can be inserted, but articulating structure length increases and stiffness reduces

Engineering Contradiction:

Improvepin coupling installationVSAvoidarticulating structure length

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

The rolling element is integrated directly into the segment structure, merging the connection and movement functions into a single compact unit. This eliminates the need for separate gap spaces and reduces the overall articulating structure length while maintaining ease of assembly through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for stable and precise steering with high curvature, reducing the overall length and maintaining structural stiffness, preventing the 'caught' wire phenomenon and ensuring smooth operation of the articulating structure.

Implementation Method 1

contact surfaces of the first segment and the second segment are rolling contact surfaces in line contact on a contact line

Methodology Applied

Scientific EffectRolling contact: Roller

Implementation Method 2

the first segment has a pin on a side, the second segment has a coupling hole into which the pin is inserted

Methodology Applied

Scientific EffectPin coupling: Pin

Data Source

PatentUS11419692B2Articulating structure using rolling joint and pin coupling, and tube insert device having the same

Publication Date: 2022.08.23 KOREA INST OF SCI & TECH

AI summary

There is disclosed an articulating structure that is steered by relative movement of a plurality of segments connected in series, the articulating structure including a first segment and a second segment arranged in contact with each other, wherein contact surfaces of the first segment and the second segment are rolling contact surfaces in line contact on a first direction contact line, the first segment has a pin on a side, the second segment has a coupling hole into which the pin is inserted, the first segment and the second segment make a relative rolling movement for translation of the first direction contact line while maintaining the line contact, and the coupling hole is formed with a larger area than the pin to allow the pin to make a relative position movement within the coupling hole during the rolling movement.