Orthopedic Rod Cam Bender With Eyelets for Precise Small-Radius Bends

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Solution Overview

Problem

Existing manual bending tools for orthopedic rods require significant physical effort, are not suitable for precise handling due to the need to focus on applying force rather than positioning, limit small bend angles, and are cumbersome with dirt accumulation issues.

Innovation Solution

A cam bender with articulated arms featuring closed eyelets at the ends, which provide axial guidance and leverage for bending, allowing for precise control and uniform bending with adjustable angles and reduced physical strain, and can be made from lightweight materials for improved ergonomics and sterility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual bending tools with articulated arms are used, then bending of orthopedic rods can be achieved, but significant physical effort is required and precise handling becomes difficult

Engineering Contradiction:
Improveprecise handlingVSAvoidphysical effort
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent replaces the traditional mechanical articulated arm system with a cam-based mechanism. The cam profile is specifically designed to convert rotational motion into the precise bending motion required, eliminating the need for the operator to directly apply large forces through complex mechanical arms. This substitution allows precise control of the bending process while reducing physical effort to simply rotating the cam.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cam acts as an intermediary element between the operator's input and the rod bending process. Instead of directly manipulating articulated arms, the operator rotates the cam, which then translates this simple rotational motion into the complex bending motion through its profile design. This intermediary mechanism provides both force multiplication and precise motion control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If traditional articulated arm tools are used, then bending can be performed, but very small bend angles and small radii of curvature cannot be achieved

Engineering Contradiction:
Improvebend angle rangeVSAvoidsmall radius bending precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent utilizes changes in the cam profile parameters to achieve different bending outcomes. By modifying the cam's geometric parameters (radius, eccentricity, profile shape), the same basic mechanism can produce a wide range of bend angles and radii of curvature, including very small values. This parameter adjustment capability provides both versatility and precision without requiring complex articulated mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Strength

If solid metal arms are used to withstand high forces, then structural strength is sufficient, but weight increases and cleaning becomes difficult due to dirt accumulation areas

Engineering Contradiction:
Improvestructural strengthVSAvoidcleaning ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces solid metal articulated arms with a cam mechanism that can be constructed from lighter materials. The cam's rotational motion provides the necessary force application without requiring heavy structural components. This substitution reduces weight while maintaining strength, and the simpler geometry of the cam eliminates complex joints and articulation points where dirt would accumulate, making cleaning easier.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise and efficient bending of orthopedic rods with smaller radii of curvature, reduces physical effort required, and minimizes the risk of rod displacement during handling while maintaining sterility and ease of cleaning.

Implementation Method 1

a cam bender consisting of two articulated arms, comprising a main roller coaxial with the axis of articulation of said arms

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

the end of each of said arms having means for exerting a bending force on a rod

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP2833814B1Bending machine with a cam for an orthopaedic rod
Publication Date: 2022.06.08 SAFE ORTHOPAEDICS SAS
  • EP2833814B1 patent drawingFigure 1
  • EP2833814B1 patent drawingFigure 2
  • EP2833814B1 patent drawingFigure 3

AI summary

The present invention concerns a bending machine with a cam formed from two articulated arms, comprising a main roller coaxial with the axis of articulation of said arms, the end of the short portion of each of said arms having means for exerting a bending stress on a rod. Said means are formed by eyelets, each of said eyelets being mounted at the end of the short portion of one of said arms so as to be rotatable relative to an axis parallel to the axis of said main roller.