Cam Locking Orthopedic Fixation Device
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Solution Overview
Problem
Existing orthopedic fixation devices are complex, heavy, and opaque to X-rays, making them difficult to use and limiting precise application of wires, bars, or nails in a radial configuration around a limb, as required in Ilizarov apparatuses.
Innovation Solution
A device with a lightweight, easy-to-use structure made of transparent composite materials, featuring quick and precise cam mechanisms for rod locking, allowing radial hole configurations and arched grooves for flexible positioning, and special clamps for orienting elongated members, enabling axial force application and dual locking/unlocking functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal locking mechanisms with screws are used, then reliable locking is achieved, but the device becomes heavy and opaque to X-rays
Solution Approach 1:
The patent employs composite materials for the frame structure that are both lightweight and transparent to X-rays, replacing traditional metal components. This resolves the contradiction by achieving reduced weight and improved radiological visibility while maintaining structural integrity through the properties of composite materials.
Solution Approach 2:
The patent replaces traditional screw-based mechanical locking systems with a cam-based locking mechanism. The cam mechanism provides reliable locking through geometric constraint and mechanical advantage, eliminating the need for screws that are heavy and X-ray opaque, thus resolving the contradiction between reliability and weight/radiological transparency.
2Manufacturing precision
If multiple holes are formed in frames for rod positioning, then precise radial alignment is possible, but the device structure becomes complex
Solution Approach 1:
The patent utilizes the natural curvature and geometry of the cam mechanism to achieve precise radial alignment. The cam's geometric shape provides inherent positioning guidance that eliminates the need for multiple alignment holes, resolving the contradiction by achieving precision through form rather than through multiple discrete positioning features.
Solution Approach 2:
The cam mechanism serves multiple functions simultaneously: it provides locking, positioning, and alignment guidance. This multi-functionality eliminates the need for separate holes for each function, reducing structural complexity while maintaining precise radial alignment capability.
3Force
If screw locking mechanisms are used, then axial force is applied to the frame, but the tightening process is slow and complex
Solution Approach 1:
The patent replaces the multi-step screw tightening process with a single-action cam mechanism. The cam geometry inherently provides mechanical advantage and force multiplication, enabling rapid application of axial force to the frame without the slow, multi-turn screw operation, thus resolving the contradiction between force application and tightening speed.
Solution Approach 2:
The cam mechanism is pre-configured with its geometric profile to automatically provide the necessary locking force and axial compression when activated. This preliminary design eliminates the need for gradual screw tightening, allowing immediate and rapid force application that resolves the productivity contradiction.
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 device simplifies installation and removal procedures, reduces X-ray opacity, and allows precise radial alignment of wires and nails, enhancing operational efficiency and patient care.
Implementation Method 1
at least one lever (12) adapted to move the two jaws (10, 11) towards each other when operated, so as to tighten the portion of frame (1)
Data Source
Figure 1
Figure 2~6
Figure 7~9
AI summary
Device for external orthopedic fixations, which comprises one or more frames (1; 61; 71) which have a substantially and/or partially annular shape and are suitable for being arranged around a limb to surround it at least partially, wherein one or more rods (2, 36; 46; 96; 106; 110) are fixed to at least one frame (1; 61; 71) by means of at least one locking mechanism (3, 6; 23; 56; 86) provided with at least two jaws (10, 11, 30, 31; 26, 27; 57, 58; 87, 88) which, when they are closed, tighten the locking mechanism (3, 6; 23; 56; 86) to a portion of the frame (1; 61;71) by exerting a prevalently axial force, wherein said jaws (10, 11, 30, 31; 26, 27; 57, 58; 87, 88) are closed by means of a cam mechanism (13, 33) suitable for being actuated by rotating at least one lever (12, 32; 90) pivoted to a first jaw (10, 30) and provided with one or more cam surfaces (13, 33) cooperating with at least one surface of the second jaw (11, 31).