Spine Connecting Rod With Nested Elastic Ball Coupling
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Solution Overview
Problem
Existing spine connecting rods with a two-segmented design face challenges in simplifying structure, reducing volume, and ensuring patient comfort while maintaining strength, leading to a foreign body feel and increased manufacturing complexity and cost.
Innovation Solution
A spine connecting rod design featuring a coupling assembly with cylindrical parts and elastic components allowing for rotational and swinging movements via a ball mechanism, using biocompatible materials for rods and coupling parts, enabling flexible and comfortable fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-segmented connecting rod with sphere and elastic components is used to improve fixation effect and patient comfort, then fixation reliability and comfort are improved, but device complexity and volume increase
Solution Approach 1:
The elastic component is nested inside the cylindrical body, with the rod passing through the elastic component. This nesting arrangement allows the elastic component to provide buffering function while being contained within the compact cylindrical structure, reducing overall device volume while maintaining the two-segmented functional design
Solution Approach 2:
The cylindrical body serves multiple functions: it provides the structural framework, contains the elastic component, and offers coupling interfaces (first and second cylindrical coupling parts) for connecting to spinal elements. This multi-functionality reduces the need for additional separate components, simplifying the overall structure
2Volume of moving object
If the size of the two-segmented connecting rod is reduced to improve patient comfort, then foreign body feel is reduced, but strength decreases
Solution Approach 1:
The connecting rod combines rigid materials (for the cylindrical body and rod) with elastic materials (for the elastic component). This composite structure allows the rigid parts to provide strength and load-bearing capacity while the elastic part provides buffering and shock absorption, enabling a compact design that maintains sufficient strength
Solution Approach 2:
The elastic component is pre-installed within the cylindrical body to provide cushioning and shock absorption before external loads are applied. This beforehand cushioning protects the rigid rod structure from impact loads, allowing the rod to be designed with smaller dimensions while maintaining strength under normal operating conditions
3Strength
If high strength metallic material is used to maintain rod strength with reduced size, then strength is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
Instead of changing material parameters to high-strength alloys, the invention changes the structural parameters by introducing the elastic component and optimizing the geometric configuration. This allows the use of standard, easily manufacturable materials while achieving the required strength through structural design rather than material selection
4Stability of the object's composition
If a rigid connector is used to ensure fixation stability, then fixation stability is improved, but patient comfort and movement flexibility deteriorate
Solution Approach 1:
The connecting rod transitions from a purely rigid structure to a dynamic structure that can adapt to varying mechanical conditions. The elastic component allows the rod to deform elastically under load, providing movement flexibility and comfort, while the rigid cylindrical body and coupling parts maintain fixation stability when needed
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 design provides a simple structure with reliable fixation, improved patient comfort, and ease of movement, while allowing for multi-segmented configurations to meet various spinal needs.
Implementation Method 1
at least one elastic part, shaped as a cylinder, disposed inside the body to provide spring forcing parallel to the first direction
Implementation Method 2
the ball of the first rod is rotationally disposed inside the coupling assembly so as to allow the first rod to rotate or/and swing about the ball
Data Source
AI summary
A spine connecting rod includes a coupling assembly, a first rod and a second rod. The coupling assembly includes a cylindrical body having first and second coupling parts and a cylindrical elastic part inside the body. The first rod, pivotally connected with the coupling assembly, has a diameter less than any inner diameter of the elastic part and the first coupling part. One end of the first rod is furnished with a ball having a diameter greater than that of the first rod and any inner diameters of the elastic part and the second coupling part. The second rod is connected with the coupling assembly. The first and second rods protrude out of the first and second coupling parts, respectively. The ball of the first rod is rotationally disposed inside the coupling assembly to allow the first rod to undergo elastic movements via the elastic part.