Orthopaedic Clamp With Hinged Jaw For Fixator

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Solution Overview

Problem

Existing orthopaedic clamps for external fixators face issues with force transmission, requiring high torque for tightening due to lever mechanisms, and have structural complexities that lead to element loss and localized load distribution causing deformations and fatigue.

Innovation Solution

A clamp design featuring a mobile jaw hinged perpendicular to the C-shaped section, which is pressed onto the connection bar by the tightening element, providing direct force transmission and distributing loads efficiently, and is composed of fewer, more secure components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a third-class lever mechanism is used for force transmission in the clamp, then the tightening force can be applied to the connection bar, but the force is demultiplied requiring high torque to be applied by the surgeon

Engineering Contradiction:
Improvetightening force transmissionVSAvoidtorque requirement
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

A mobile jaw acts as an intermediary element between the tightening screw and the connection bar. The mobile jaw is pressed by the tightening screw against the connection bar, providing a mechanical advantage that multiplies the tightening force, thereby reducing the torque requirement for the surgeon while effectively restraining the connection bar.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If multiple separate components are used in the clamp structure, then the clamp can perform its tightening function, but the elements can be easily lost and reassembly becomes complicated

Engineering Contradiction:
Improveclamp functionalityVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The clamp design integrates multiple functions into fewer components. The mobile jaw is hinged to the first attachment and works in conjunction with the tightening screw that traverses both attachments, creating a more unified structure that reduces the number of separate elements that could be lost, while maintaining the necessary tightening and restraining functions.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the tightening element traverses both attachments along a transverse axis, then the clamp can transition from loosened to tightened configuration, but the relative orientation of attachments must be blocked to ensure stability

Engineering Contradiction:
Improveconfiguration transitionVSAvoidrelative orientation stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The clamp design allows dynamic transition between loosened and tightened configurations. In the loosened state, the two attachments can be reciprocally rotatable around the axis of rotation, allowing the surgeon to set the relative orientation. When the tightening element is tightened, it blocks the relative orientation of the attachments, providing stability for the final fixed configuration.

Inventive Principle:
Principle #15Dynamics

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 clamp achieves efficient force transmission and load distribution, reducing the need for high torque and minimizing the risk of element loss, while maintaining stability and resistance to fatigue.

Implementation Method 1

a tightening element, at least partially threaded, which traverses and connects the first and the second attachment along an axis of rotation transverse to the extension of the external and internal arms; the tightening of said tightening element bringing the clamp from a loosened configuration to a tightened configuration

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

the first attachment comprises a mobile jaw hinged, along an hinging axis perpendicular to the plane of the C-shaped section of the lateral housing, at the free end of the external arm of the first attachment

Methodology Applied
Scientific EffectHinge mechanism: Hinge

Implementation Method 3

the tightening of said tightening element causing a pressure of the mobile jaw on the first connection bar in the direction of the internal arm, thus performing an action of restraining of the first connection bar in the lateral housing

Methodology Applied
Scientific EffectMechanical force transmission: Force

Data Source

PatentEP2319436B1Clamp for external orthopaedic fixing device
Publication Date: 2013.02.13 ORTHOFIX SRL
  • EP2319436B1 patent drawingFigure 1
  • EP2319436B1 patent drawingFigure 2~2A
  • EP2319436B1 patent drawingFigure 3

AI summary

A clamp (1; 1'; 1") for orthopaedic external fixator (100), practical and safe to use, comprises: a first attachment (2), provided with a pair of arms respectively internal (22) and external (21) defining one with the other a lateral housing (20) with C-shaped section for housing a first connection bar (101) and comprising a mobile jaw (5) hinged on its external arm (21); a second attachment (3; 3'; 3") for allowing the connection of the clamp (1; 1'; 1") to a second component (102; 102') of the orthopaedic external fixator (100); a tightening element (4), at least partially threaded, which traverses and connects the first and the second attachment (2, 3; 3'; 3") along an axis of rotation (x) and whereto the mobile jaw (5) is subjected, the tightening of the tightening element (4) bringing the clamp from a loosened configuration, at which the two attachments (2, 3; 3'; 3") are reciprocally rotatable around the axis of rotation (x), to a tightened configuration, at which the relative orientation of the attachments (2, 3; 3'; 3") is blocked; causing a pressure of the mobile jaw (5) on the first connection bar (101) in the direction of the internal arm (22), performing therefore an action of restraining of the first connection bar (101) in the lateral housing (20).