Artificial Disc Rotational Resistance via Segmented Intermediate Section
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Solution Overview
Problem
Existing artificial discs for spinal replacement lack effective mechanisms to resist relative rotation between vertebrae throughout the full range of motion, with current designs often providing inadequate resistance, especially during initial stages of rotation.
Innovation Solution
The artificial disc features a resilient intermediate section with a base portion that resists rotation from the initial to the second position and a protruding portion that provides increased resistance from the second to the third position, utilizing a ring and web structure with protrusions and projections to enhance rotational resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the entire intermediate section resists rotation throughout the full range of motion, then rotational stability is improved, but the complexity of the structure increases and may limit the range of motion
Solution Approach 1:
The intermediate section is divided into multiple functional portions: a first portion that resists rotation throughout the full range of motion and a second portion that is ineffective during initial rotation but becomes effective later. This segmentation allows each portion to specialize in specific rotational phases, achieving comprehensive rotational control without requiring a uniformly complex structure throughout the entire intermediate section.
Solution Approach 2:
Different regions of the intermediate section are designed with different rotational resistance properties. The first portion provides rotation resistance across the full range, while the second portion is specifically designed to be ineffective during initial rotation (from first to second position) and only becomes effective during later rotation phases (from second to third position). This local differentiation optimizes both stability and range of motion.
2Ease of operation
If the intermediate section provides resistance throughout the full range of rotation, then motion control is improved, but the ease of operation deteriorates due to restricted initial movement
Solution Approach 1:
The intermediate section's rotational resistance is made dynamic rather than static. The second portion transitions from being ineffective to effective as rotation progresses, allowing the device to adapt its resistance characteristics based on the current position and phase of rotation. This dynamic behavior enables easier initial movement while maintaining control throughout the full range of motion.
Solution Approach 2:
The rotational resistance is applied periodically rather than continuously. The second portion of the intermediate section provides resistance during specific phases of rotation (from second to third position) while being ineffective during other phases (from first to second position). This periodic application of resistance allows for controlled movement through different stages of rotation.
3Stability of the object's composition
If protrusions and projections are used to enhance rotational resistance, then stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The protrusions on the intermediate section are designed to engage with corresponding projections on the retainers in a nested manner. The protrusions extend inwardly from the ring toward the central portion, and the projections on the retainers are positioned to engage with these protrusions at specific rotational positions. This nested arrangement provides enhanced rotational resistance while maintaining a relatively compact and manufacturable structure.
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 design effectively resists relative rotation between vertebrae throughout the range of motion, with incremental increases in resistance as the disc rotates, providing improved stability and motion control compared to previous designs.
Implementation Method 1
An intermediate section is connected with the first and second retainers. The intermediate section of the artificial disc resists relative rotation between the first and second retainers.
Implementation Method 2
A plurality of protrusions may extend inwardly from the ring toward a central portion of the intermediate section. A plurality of projections on the retainers are engagable with the protrusions.
Data Source
AI summary
An artificial disc includes an intermediate section which is disposed between upper and lower retainers. The intermediate section includes a first portion which resists rotation of one of the retainers, for example, the upper retainer, from a first position to a second position. A second portion of the intermediate section of the artificial disc resists rotation of the upper retainer from the second position to a third position. The second portion of the intermediate section of the artificial disc is ineffective to provide significant resistance to relative rotation between the retainers during rotation of the upper retainer relative to the lower retainer from the first position to the second position. The artificial disc may be provided with projections which engage protrusions on the intermediate section to resist rotation of the upper retainer relative to the lower retainer from the second position to the third position.