Star-Shaped Collet Suture Anchor for High-Tension Cable Grip
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Solution Overview
Problem
Polymer-based surgical cables are difficult to engage and lock under high tension due to slippery surfaces, material deformation, and delicate fibers, which complicates gripping and retention without causing damage.
Innovation Solution
A surgical cartridge with a star-shaped collet that radially collapses to grip the cable uniformly, featuring a conical shape with varying diameters and a set of gripping fingers to distribute pressure evenly, ensuring a firm yet gentle grip on the cable as it shrinks under tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If increased pressure is applied to prevent cable slippage, then gripping reliability is improved, but cable damage (cutting or fraying) occurs
Solution Approach 1:
The gripping force is divided among multiple individual fingers (at least three fingers) that contact the cable at different locations. This segmentation distributes the total gripping force across multiple contact points, reducing the pressure at each individual finger-cable interface while maintaining sufficient total gripping force to prevent slippage under tension.
Solution Approach 2:
Each finger is designed with specific geometric characteristics (radius of curvature, length, spacing) optimized for local contact with the cable surface. The fingers have varying radii of curvature to match the cable's geometric properties, creating optimal local pressure distribution that prevents both slippage and cable damage at each contact point.
2Adaptability or versatility
If the gripping device is made flexible to accommodate cable shrinkage under tension, then adaptability is improved, but gripping force is reduced
Solution Approach 1:
The fingers are designed as flexible elements that can dynamically adjust their position and contact pressure in response to cable diameter changes. The flexible material and geometric design allow the fingers to collapse or flex inward as the cable shrinks under tension, maintaining continuous contact and gripping force throughout the tensioning process without requiring rigid structural components.
3Stability of the object's composition
If the cable is gripped uniformly to prevent fiber breakage, then cable integrity is preserved, but gripping effectiveness is reduced
Solution Approach 1:
The uniform gripping requirement is satisfied by segmenting the contact around the cable circumference into multiple discrete finger contact points. This segmentation allows each finger to apply controlled, localized pressure that contributes to overall uniform gripping while preventing any single point from concentrating excessive force that could break delicate fibers.
Solution Approach 2:
The fingers are constructed from composite materials or multi-layer structures that combine different material properties to achieve both softness (to prevent fiber breakage) and hardness (to maintain gripping effectiveness). This composite construction allows the fingers to be sufficiently soft to distribute pressure uniformly across the cable surface while remaining hard enough to maintain adequate gripping force under tension.
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 solution provides a bio-compatible, high-tension suture anchor capable of maintaining a consistent pressure of 2500-3500 psi over a small area, effectively securing the cable without damage, suitable for the healing process, and is designed to accommodate up to 15% cable diameter shrinkage.
Implementation Method 1
The collet is hollow and conically shaped on both the inside and outside surfaces... the diameter of the inside surface is smaller at the exposed end than at the insertion end
Implementation Method 2
The polymer cable stretches under high tension. As tension is applied, the diameter of the nylon or other polymeric material core shrinks by approximately 12%
Data Source
AI summary
The present invention describes a bio-medically compatible gripping device capable of radial collapse in accordance with the shrinkage of a nylon or other polymeric material cored surgical cable undergoing tension while maintaining a firm grip for prolonged periods of time. It provides a gripping device capable of maintaining a non-damaging hold on the outer surface of a slippery delicate cable under high tension for a sufficient time in which the healing process can occur.