Flexible Torque Shaft with Segmented Notch Coupling

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Solution Overview

Problem

Current flexible torque-transmitting instruments are difficult to align and clean, and often struggle with reaching hard-to-access areas due to their rigidity and design limitations.

Innovation Solution

A flexible torque-transmitting instrument with a shaft comprising torque-transmitting elements coupled in series, featuring rotational and tiltable connections via notch and protrusion coupling features, and an alignment member made from spring-elastic material to facilitate bending and alignment while maintaining torque transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a rigid shaft is used to transmit torque, then torque transmission is reliable, but the instrument cannot reach hard-to-access areas

Engineering Contradiction:
Improveability to reach hard-to-access areasVSAvoidtorque transmission reliability
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The shaft is divided into multiple torque transmitting elements coupled in series, allowing each segment to rotate relative to adjacent segments while maintaining torque transmission through the coupling features (notch and protrusion). This segmentation enables the shaft to bend and reach difficult areas while preserving torque transmission capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shaft transitions from a rigid structure to a dynamic, flexible structure where torque transmitting elements can tilt and rotate relative to each other. This dynamic configuration allows the shaft to adapt its shape to access hard-to-reach areas while maintaining mechanical coupling for torque transmission.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a flexible shaft with complex coupling features is used, then the instrument can reach hard-to-access areas, but alignment becomes difficult

Engineering Contradiction:
Improveflexibility to reach hard-to-access areasVSAvoidalignment ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The coupling features use asymmetric geometry with a notch in one torque transmitting element and a corresponding protrusion in the adjacent element. This asymmetric design provides automatic alignment guidance during insertion, making it easier to assemble the flexible shaft segments in the correct orientation.

Inventive Principle:
Principle #4Asymmetry

3Adaptability or versatility

If traditional flexible shaft design is used, then flexibility is achieved, but cleaning becomes difficult

Engineering Contradiction:
ImproveflexibilityVSAvoidcleaning ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The segmented structure with discrete coupling features creates well-defined interfaces between torque transmitting elements. These defined interfaces allow for effective cleaning access and sterilization, addressing the cleaning difficulty while maintaining flexibility through the segmented design.

Inventive Principle:
Principle #1Segmentation

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 instrument allows for reversible bending and improved alignment, enabling effective torque transmission to hard-to-reach areas while minimizing wear and maintaining the alignment member's integrity, thus enhancing usability and durability.

Implementation Method 1

an alignment member made from spring-elastic material to facilitate bending and alignment while maintaining torque transmission

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4169460A1Instrument for transmitting torque
Publication Date: 2023.04.26 STRYKER EUROPEAN OPERATIONS LIMITED
  • EP4169460A1 patent drawingFigure 1
  • EP4169460A1 patent drawingFigure 2
  • EP4169460A1 patent drawingFigure 3a~3b

AI summary

An instrument for transmitting torque is described. The instrument comprises a torque receiving portion at a proximal end of the instrument, a torque delivering portion at a distal end of the instrument, and a flexible shaft extending between the torque receiving portion and the torque delivering portion. The flexible shaft comprises torque transmitting elements coupled in series along a longitudinal direction of the shaft. A female coupling feature of a torque transmitting element comprises a notch and a male coupling of an adjacent torque transmitting element comprises a protrusion sized to fit into the notch. The notch has a constant width or a narrowing width starting from an outer surface of the torque transmitting element comprising the notch.