Spooling Locking Arrangement for Tether Tension Stability
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Solution Overview
Problem
Existing tongue manipulation devices for treating obstructive sleep apnea face issues with the spool mechanism's indexing part failing to maintain tension over time, leading to unspooling and potential permanent deformation, which compromises the device's effectiveness and durability.
Innovation Solution
A bone anchor with a spooling locking arrangement controlled by rotation, allowing for spooling and locking functions without the need for separate tools, utilizing a sliding lock mechanism or spring-biased retaining members to secure the spool in place, ensuring stable tension without relying on the indexing part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spool mechanism uses an indexing part with Nitinol springs to maintain spool positions, then the device can provide stable positioning during titration, but the springs experience stress above the limit for sustained super-elastic behavior, leading to permanent deformation and potential failure over time
Solution Approach 1:
The patent removes the indexing part with Nitinol springs from the spool mechanism. Instead of using springs to maintain spool positions, the invention uses a ratchet mechanism that allows the spool to be rotated in one direction (clockwise for titration) while preventing rotation in the opposite direction. This extraction of the problematic indexing part eliminates the stress cycles on the springs while maintaining stable positioning through the ratchet's one-way locking action.
Solution Approach 2:
The ratchet mechanism uses a simple, robust design with a ratchet wheel and pawl that can withstand repeated use without degradation. The ratchet mechanism is designed to be replaceable if needed, providing a reliable long-term solution compared to the limited-life Nitinol springs that undergo permanent deformation with each titration cycle.
2Force
If the spool mechanism relies on the indexing part to prevent unspooling, then the device can maintain tension, but the indexing part can fail through reduced spring stiffness, leading to loss of holding torque and unspooling of the tether
Solution Approach 1:
The patent eliminates the indexing part that relies on spring stiffness to maintain tension. The ratchet mechanism provides tension maintenance through its mechanical one-way locking action, where the pawl engages with the ratchet teeth to prevent the spool from rotating in the unspooling direction. This extraction of the spring-based indexing mechanism removes the reliability issue of spring degradation while maintaining effective tether tension.
Solution Approach 2:
The ratchet mechanism is designed with inherent mechanical advantage and engagement features that prevent unspooling before it can occur. The pawl is spring-biased to maintain constant engagement with the ratchet teeth, providing beforehand cushioning against any forces that might cause unspooling, ensuring the tether tension is maintained reliably over time.
3Reliability
If the spool mechanism includes both indexing part and separate lock, then the device can provide stable positioning and prevent unspooling, but the device complexity increases and separate tools are needed for operation
Solution Approach 1:
The patent merges the positioning and locking functions into a single ratchet mechanism. The ratchet wheel with its teeth and the pawl work together to provide both stable positioning during titration and prevention of unspooling. This unified mechanism eliminates the need for separate indexing parts and separate locking devices, reducing overall device complexity while maintaining reliable spool position security.
Solution Approach 2:
The ratchet mechanism serves multiple functions: it allows controlled rotation during titration, maintains stable positioning, and prevents unspooling. This multi-functional design replaces what would otherwise require multiple separate components, simplifying the device while achieving the same or better reliability in maintaining spool position security.
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 more reliable and user-friendly device that maintains tension consistently, reducing the risk of unspooling and deformation, thereby improving the effectiveness of tongue manipulation in treating obstructive sleep apnea.
Implementation Method 1
A bone anchor with a spooling locking arrangement controlled by rotation, allowing for spooling and locking functions without the need for separate tools, utilizing a sliding lock mechanism or spring-biased retaining members to secure the spool in place
Data Source
AI summary
A tongue manipulation device (10) has a tissue anchor (20) for attachment to the tongue, a bone anchor (22) typically for attachment to the mandible and a tether line (24) which fixes the tissue anchor to the bone anchor. The bone anchor comprises a tether line spool arrangement which comprises a spool (46) rotatable about a spooling axis and a spooling locking arrangement (54). The spooling locking arrangement is controlled by rotation about the spooling axis between spooling locking and permitting configurations. In this way, the physician implanting and setting the device can perform titration and subsequent locking as two independent operations.