Shape Adaptive Jaw Members with Composite Cheeks for Torsion Stability

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Solution Overview

Problem

Medical gripping instruments used in endoscopic surgery often suffer from low dimensional stability, particularly with respect to torsion impacts, due to rigid jaw members that can cause damage to grasped tissues by developing point loads.

Innovation Solution

The jaw members are designed with inner and outer cheeks of different cross-sectional configurations and materials, featuring a wider inner cheek and a rounded or stepped outer cheek, along with a trapezoidal connecting brace and reinforcement ribs, to enhance torsion stability while maintaining shape-adaptive flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If rigid jaw members are used for grasping tissue, then the gripping force is sufficient, but point loads develop that can cause damage to the grasped tissue

Engineering Contradiction:

Improvegripping forceVSAvoidtissue damage from point loads

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The jaw members are designed with a double-layered structure consisting of an inner cheek and an outer cheek that can deform flexibly. This flexible shell structure allows the jaw to adapt to the shape of the tissue being grasped, distributing the gripping force over a larger surface area and eliminating harmful point loads while maintaining sufficient gripping force.

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the inner and outer cheeks are produced from flat binding material to achieve shape adaptability, then flexibility is improved, but dimensional stability and torsion resistance decrease

Engineering Contradiction:

Improveshape adaptabilityVSAvoiddimensional stability and torsion resistance

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The jaw member employs a composite structure with an inner cheek and an outer cheek made from different materials or with different cross-sectional configurations. The inner cheek provides flexibility for shape adaptation, while the outer cheek with its rounded or stepped configuration and different material properties enhances dimensional stability and torsion resistance, creating a composite structure that combines both requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The outer cheek is configured with a rounded or stepped outside surface instead of a flat configuration. This curved geometry increases the surface inertial moment and significantly improves dimensional stability and torsion resistance while maintaining the shape-adaptive flexibility of the jaw member.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Volume of moving object

If the outer contour of outer cheeks is adapted to the inner contour of the trocar sheath to maximize construction space, then space utilization is improved, but the design complexity increases

Engineering Contradiction:

Improveconstruction space utilizationVSAvoiddesign complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The outer contour of the outer cheek is locally adapted to match the inner contour of the trocar sheath. This local geometric adaptation allows the jaw member to be optimally positioned within the trocar sheath, maximizing the available construction space without requiring complete redesign of the entire structure, thus balancing space utilization with design complexity.

Inventive Principle:

Principle #3Local quality

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

This design increases the surface inertial moment and torsion resistance of the jaw members, allowing for effective grasping without damaging tissues and optimizing the use of construction space within the trocar sheath.

Implementation Method 1

the Fin Ray Effect refers to a double-layered structure that performs a directed deformation through force impact, for example by sidestepping in the force contact point and at its ends turning against the force direction, and thus adapts to the shape of the object that induces the force

Methodology Applied

Scientific EffectFin Ray Effect:

Data Source

PatentUS9498241B2Medical instrument with shape adaptive gripping tool

Publication Date: 2016.11.22 KARL STORZ SE & CO KG

AI summary

A medical instrument with a shaft, a handle positioned on the proximal end of the shaft, a tool positioned on the distal end of the shaft with two jaw members that can be displaced between an open and a closed position, and with an actuating element by which the handle and tool are in active connection with one another and where each jaw member of the tool consists of an inner cheek and an outer cheek, which are connected with one another on the distal end of each jaw member and are distanced from one another in the proximal direction, and at least one connecting brace is positioned between the inner cheek and the outer cheek. The medical instrument has jaw members, while preserving flexibility, have an increased dimensional stability, in particular with respect to torsion impact. The inner cheek and the outer cheek of each jaw member is configured differently with respect to the shape of their cross-section, with the inner cheek configured as wider than the outer cheek and with the inner cheek of each jaw member having rounded or stepped configuration.