External Fixation Clamp With Tilting Lock for Bone Curvature Adjustment

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Solution Overview

Problem

Existing external fixation devices for bone fractures and deformities are not effective in modifying the relative curvature of bone stumps after application, leading to complex and unstable positioning of clamps, and often require loosening of locking mechanisms, affecting the correct alignment and movement of bone segments.

Innovation Solution

A clamp design with a first locking unit and a second locking unit featuring a dovetail shape for slidable tilting, combined with a friction pin and graduated angular scale, allowing precise angular adjustment and stable fixation of bone screws and connecting bars, enabling easy modification of bone stump orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing external fixation devices are used to fix bone stumps, then the bone segments can be stabilized, but the relative curvature of bone stumps cannot be modified after application

Engineering Contradiction:
Improveability to modify bone stump curvatureVSAvoidstability of clamp positioning
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The clamp incorporates a tilting mechanism that allows the locking unit to rotate relative to the connecting bar, enabling dynamic adjustment of bone stump orientation after the device is applied. The friction pin and angular scale facilitate controlled tilting movements while maintaining stable positioning at desired angles.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clamp is divided into distinct functional units: a locking unit for securing bone screws, a tilting mechanism for angular adjustment, and a friction pin system for maintaining position. This segmentation allows independent optimization of each function while resolving the contradiction between adaptability and stability.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If locking clamps are loosened to modify screw orientation, then bone stump positioning can be adjusted, but the correct relative positioning of clamps is adversely affected

Engineering Contradiction:
Improveability to adjust screw orientationVSAvoidprecision of clamp alignment
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The tilting mechanism enables continuous angular adjustment of the locking unit relative to the connecting bar without requiring complete loosening of the clamp system. The friction pin maintains precise positioning at each angular setting, preserving alignment accuracy throughout the adjustment range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The friction pin mechanism replaces traditional locking nuts and threaded connections with a friction-based holding system that maintains precise angular positions through controlled friction rather than mechanical interlocking, simplifying adjustment while maintaining precision.

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

3Strength

If traditional clamps are used for external fixation, then bone segments can be secured, but reciprocal movement between clamps and connecting bars occurs

Engineering Contradiction:
Improvesecuring capability of bone segmentsVSAvoidstability of clamp-connecting bar connection
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The friction pin acts as an intermediary element between the locking unit and the connecting bar, providing a stable friction-based connection that prevents reciprocal movement while allowing controlled angular adjustment. This intermediary mechanism resolves the instability issue without compromising the securing capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a practical and versatile solution for adjusting and maintaining precise angular positions of bone segments, enhancing the stability and adjustability of external fixation devices, particularly in cases of marked bone curvature.

Implementation Method 1

a friction pin (13) having an end shaped to match a portion of the dovetail section... suitable frictional action on the lower valve part (82)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4374807B1Clamp for external fixation device
Publication Date: 2025.11.12 CITIEFFE SRL
  • EP4374807B1 patent drawingFigure 1~2
  • EP4374807B1 patent drawingFigure 3~5
  • EP4374807B1 patent drawingFigure 6~8

AI summary

Described is a clamp (2) of an external fixation device (1) for the treatment of bone fractures, comprising a first locking unit (8) designed to lock at least two bone screws (4) and a second locking unit (9) designed to lock at least one connecting bar (5, 6). [Fig. 1]