External Fixation Component with Three-Axis Rotation

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Solution Overview

Problem

Existing external fixation systems face challenges with complex rotation mechanisms that are difficult to clean and lack versatility, particularly in accommodating multiple capture elements with limited rotational freedom.

Innovation Solution

An external fixation component featuring two capture members coupled by a rotation member that allows rotation about three axes, with central locking screws, rotation blockers, and spring-actuated clamping assemblies, enabling flexible positioning and easy handling of rods or pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a complex rotation member is directly connected to capture members to enable rotation about three axes, then the device provides versatile positioning capability, but the device becomes difficult to clean and maintain

Engineering Contradiction:
Improvepositioning capabilityVSAvoidcleanability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The device is divided into separable components: capture members, a rotation member with blocking elements, and a central disc element. The blocking elements can be removed from the capture members and repositioned on the rotation member, allowing the capture members to be detached and cleaned separately without disassembling the entire mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blocking elements are extracted from the capture members and transferred to the rotation member. This separation allows the capture members to be removed from the assembly for easy cleaning while the rotation member remains in place, solving the cleanability issue while preserving the three-axis rotation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If a single activation element is used to secure capture members from rotation, then handling is facilitated, but the device loses versatility in orienting capture members independently

Engineering Contradiction:
ImprovehandlingVSAvoidorientation freedom
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The device transitions from a static single-activation system to a dynamic system where blocking elements can be selectively positioned. Each capture member can be independently locked or unlocked by positioning blocking elements, allowing flexible handling where one capture member can be secured while the other remains freely orientable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The single activation mechanism is segmented into two independent blocking elements that can be positioned separately. This allows independent control of each capture member's orientation, providing versatility while maintaining ease of operation through simple blocking/unblocking actions.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If two capture members are clamped to be positioned in any angular position, then adaptability is improved, but the device requires more space for the rotation mechanism

Engineering Contradiction:
Improveangular positioningVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The rotation mechanism utilizes the radial dimension of the central disc element to provide three axes of rotation. By arranging blocking elements radially on the disc, the system achieves multi-axis rotation capability within a compact footprint, reducing the overall volume required for the rotation mechanism.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The central disc element serves multiple functions: it provides the rotation axis, holds the blocking elements, and enables three-axis rotation capability. This multi-functional design reduces the number of separate components needed, thereby reducing the overall device volume while maintaining angular positioning adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2294994B1External fixation component
Publication Date: 2018.04.04 STRYKER EUROPEAN HOLDINGS I LLC
  • EP2294994B1 patent drawingFigure 1~2
  • EP2294994B1 patent drawingFigure 3
  • EP2294994B1 patent drawingFigure 4

AI summary

An external fixation component comprises two capture members (10, 20) adapted to capture independently a first and a second element of an external fixation system. Between them a rotation member (30) is provided, coupled to both capture members (10, 20) such that the coupling allows the two capture members (10, 20) to rotate about three axes relative to each other. Each capture member (10, 20) comprises a central locking screw (40) extending therethrough and defining a longitudinal axis of the associated capture member (10, 20). The rotation member (30) comprises two rotation blockers (63, 64), each blocker (63, 64) providing one interface surface (55) adapted to be in contact with a complementary interface surface (45) of one of the capture members (10,20), each blocker (63, 64) further providing a surface opposite to said interface surface (55) comprising an inner cylindrical surface (86). The rotation member (30) comprises a central disc element (61, 62) forming a rolling surface (85) as complementary surface to said inner cylindrical surface (86) of the corresponding rotation blocker (63, 64) and it comprises two nuts (65, 66), wherein each nut (65, 66) is associated to one locking screw (40) of a corresponding capture member (10, 20) and wherein each locking screw (40) of a capture member (10, 20) is extending through the corresponding rotation blocker (63, 64) and engages the corresponding nut (65, 66) for an individual locking of each capture member (10, 20, 110, 120).