Star-Shaped Collet Gripping Polymer Cable Under Tension
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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 the delicate nature of braided fibers, which existing gripping devices often damage or fail to secure effectively.
Innovation Solution
A surgical cartridge with a star-shaped collet that radially collapses to grip the cable, distributing pressure uniformly and maintaining contact area, combined with a bio-compatible high tension suture anchor that applies consistent pressure over a small area to secure the cable without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gripping devices apply high pressure to secure polymer cables under high tension, then the cable can be retained, but the cable surface is cut or frayed
Solution Approach 1:
The gripping device is divided into multiple individual fingers (typically 5-15 fingers) that can independently adjust and collapse. Each finger acts as an independent gripping element, allowing distributed contact pressure across the cable surface rather than concentrated pressure at a single point, thereby preventing cable damage while maintaining secure retention
Solution Approach 2:
The gripping device employs flexible fingers that can dynamically collapse and adapt to the cable's dimensional changes under tension. The fingers are designed to be flexible enough to accommodate the cable's shrinkage (approximately 12% diameter reduction) while maintaining continuous contact and gripping force, preventing both slippage and damage
2Reliability
If the gripping device uses a rigid structure to maintain firm grip, then the cable can be secured, but the delicate braided fibers break due to asymmetric or concentrated pressure
Solution Approach 1:
The gripping device is divided into multiple individual fingers (typically 5-15 fingers) that can independently adjust and collapse. Each finger acts as an independent gripping element, allowing distributed contact pressure across the cable surface rather than concentrated pressure at a single point, thereby preventing cable damage while maintaining secure retention
Solution Approach 2:
Each finger is designed with specific local properties including appropriate flexibility, contact surface area, and collapse characteristics. The fingers have varying degrees of flexibility and contact pressure distribution optimized for different regions of the cable, ensuring uniform gripping force that protects the delicate braided fibers while maintaining secure retention
3Reliability
If the collet is designed to collapse radially to accommodate cable shrinkage, then the grip is maintained under tension, but the device complexity increases
Solution Approach 1:
The collet is segmented into multiple discrete fingers rather than a monolithic structure. This segmentation allows each finger to independently collapse and adapt to the cable's dimensional changes, achieving the necessary flexibility and cable accommodation while maintaining a relatively simple overall device architecture that can be manufactured efficiently
Solution Approach 2:
The fingers are constructed from flexible materials with appropriate wall thickness that allows radial collapse while maintaining structural integrity. The flexible finger design enables the collet to accommodate the cable's shrinkage under tension (approximately 12% diameter reduction) without requiring complex mechanical mechanisms, thereby maintaining grip while limiting device complexity
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 firm, gentle, and uniform grip on polymer-based surgical cables, accommodating cable shrinkage and maintaining securement under high tension without causing damage, suitable for the healing process.
Implementation Method 1
the frictional force F required to retain such a cable must be applied in such a way that it does not cause damage, yet be of sufficiently significant magnitude to maintain a grip under high tension
Implementation Method 2
The collet is hollow and conically shaped on both the inside and outside surfaces... The collet of the present design is comprised of several fingers that move radially inward to grip the cable
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.