Disposable Co-Molded Metal Rasp With Flexible Polymer Shaft

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Solution Overview

Problem

Reusable surgical tools require frequent recalibration and sterilization, increasing the risk of contamination and complexity in orthopedic procedures, while disposable tools lack sufficient grip and flexibility for precise bone manipulation.

Innovation Solution

A disposable cutting tool with an elongated molded body and a support shaft affixed to a rasp head, featuring non-circular gripping surfaces and fluid connections for improved grip and flexibility, allowing for ergonomic handling and reduced contamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reusable surgical tools are used, then the tools can be recalibrated and reused, but they require frequent sterilization and recalibration which increases contamination risk and procedural complexity

Engineering Contradiction:
Improvecontamination riskVSAvoidsterilization and recalibration procedures
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a disposable rasp head that is discarded after a single use, eliminating the need for sterilization and recalibration procedures. This disposable approach reduces contamination risk while simplifying the overall system complexity by removing maintenance requirements.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If disposable cutting tools are used, then sterilization and recalibration are eliminated, but the tools lack sufficient grip and flexibility for precise bone manipulation

Engineering Contradiction:
Improvesterilization requirementsVSAvoidgrip and flexibility
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The handle portion incorporates non-circular gripping surfaces with asymmetric geometries including divots, bumps, and flat regions. These asymmetric features provide preselected gripping surfaces that enhance finger placement and control, improving ease of operation while maintaining disposable simplicity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The handle portion features localized variations in surface geometry with specific gripping regions that have different properties (divots for finger placement, bumps for tactile feedback, flat regions for thumb pressure). These local quality variations enhance grip and flexibility without complicating the overall disposable design.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the rasp head is firmly attached to the support shaft, then cutting precision is improved, but the tool lacks flexibility for precise bone manipulation

Engineering Contradiction:
Improvecutting precisionVSAvoidflexibility for bone manipulation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The support shaft is constructed from flexible polymer material that provides controlled flexibility while maintaining structural integrity. This flexible shaft can bend and adapt to complex bone geometries during manipulation, while the rasp head remains firmly attached through co-molding to ensure cutting precision.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The tool combines different materials with complementary properties: a flexible polymer support shaft for adaptability and a rigid rasp head for cutting precision. The co-molded connection creates a composite structure that integrates both flexibility and firm attachment, resolving the contradiction between these opposing requirements.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3784151B1Disposable rasp for medical instruments
Publication Date: 2025.01.01 ECA MEDICAL INSTR
  • EP3784151B1 patent drawingFigure 1
  • EP3784151B1 patent drawingFigure 2
  • EP3784151B1 patent drawingFigure 3A

AI summary

Disclosed are aspects of a hybrid plastic and co-molded metal cutting head and a method of forming same. The method includes forming a metal rasp head having a fluid pathway there through and molding an elongated body with support into the rasp head via said fluid pathway wherein the fluid pathway branching into one or more sides.