Polymeric External Fixator Element With Rough Ablated Surface
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
External fixators made from lightweight materials like plastics or polymers experience positional changes due to frictional issues, leading to instability over time, especially in long-term use.
Innovation Solution
The use of a rough ablated surface on polymeric elements, such as rods and pins, achieved through techniques like sandblasting or etching, which exposes fiber ends to enhance friction and grip between clamping and rod/pin surfaces, utilizing materials like polyamide or PEEK with embedded glass, carbon, or aramid fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightweight polymeric materials are used for external fixator elements, then weight is reduced and X-ray transparency is improved, but friction between contacting surfaces decreases leading to positional instability
Solution Approach 1:
The patent applies local quality by treating only the contacting surfaces of the polymeric elements with a rough ablated structure, while the bulk material remains lightweight polymer. This localized surface treatment increases friction where needed (at contact points) without compromising the overall weight reduction and X-ray transparency benefits of the polymeric material throughout the entire device.
Solution Approach 2:
The patent creates a composite structure by combining polymeric material with a rough ablated surface layer. The ablated surface creates a composite interface between the polymeric element and contacting elements, combining the low weight and X-ray transparency of polymer with the high friction characteristics of the roughened surface, effectively merging benefits of both material types at the critical contact interface.
2Ease of manufacture
If smooth surfaces are used on polymeric elements, then manufacturing is easier and friction is low, but grip between clamp jaws and rods/pins deteriorates over time
Solution Approach 1:
The rough ablated surface structure is created during the manufacturing process itself, before the product is put into service. This preliminary action of surface treatment ensures that the friction-enhancing structure is already in place during manufacturing, eliminating the need for post-manufacturing adjustments and ensuring consistent grip performance from the start of device operation.
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
This approach significantly increases friction between contacting surfaces by over 50%, ensuring stable positioning of bone fragments during healing, with enhanced durability and reduced risk of fiber detachment or contamination.
Implementation Method 1
a bearing having a plastic material on plastic material combination has a low friction coefficient, wherein it is possible, according to the invention, to change the low friction coefficient of plastic material when fibers parts are protruding over the surface of the plastic material
Implementation Method 2
The term ablated surface comprises opening the surface to a gas stream having abrasive elements such as sand-blasting, brushing or similar procedures which erode the surface and especially etching
Data Source
AI summary
A polymeric external fixator element, such as a rod or a pin or a clamp, has at least one contacting surface. At least one of the contacting surfaces of the element responsible to establish connection between the element and a different external fixator element is provided with a rough ablated structure. The clamping can be improved if one of the polymeric elements comprise fibers having fiber parts protruding above the surface.