Bone Anchor Spool Arrangement for Tether Slack Management
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Solution Overview
Problem
Existing tongue manipulation devices for treating obstructive sleep apnea face issues with unspooling of the tether line due to indexing mechanism failure and lack of tactile feedback for tether tightness, leading to reduced effectiveness in maintaining airway patency during sleep.
Innovation Solution
A bone anchor with a spool arrangement that allows for initial free spooling to remove slack without engaging the indexing part, followed by indexed spooling with audible feedback, using a rotary drive member to selectively couple the indexing and spool parts, ensuring the indexing function is only engaged after slack removal, thereby reducing wear and providing tactile and audible feedback on tension adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the indexing part is engaged during initial spooling to remove slack, then the tether line can be tightened with audible feedback, but the indexing mechanism experiences increased wear and may fail leading to unspooling
Solution Approach 1:
The spool part is operated in advance to remove all slack from the tether line before the indexing part is engaged. This preliminary action prepares the system by eliminating the need for the indexing mechanism to handle slack removal, thereby reducing wear and preventing failure while maintaining the ability to provide audible feedback during the subsequent tightening phase.
Solution Approach 2:
The spooling process is divided into two distinct phases: a first phase where only the spool part operates to remove slack, and a second phase where the indexing part is engaged to provide indexed tightening with audible feedback. This segmentation isolates the high-wear slack removal task from the precision indexing mechanism, improving overall reliability.
2Loss of information
If the indexing part operates during the entire spooling process, then audible feedback is provided throughout, but the user cannot feel when the tether line is tight due to minimum torque requirements
Solution Approach 1:
All slack removal is performed in advance during the first configuration before the indexing part is engaged. This allows the user to feel the tether line becoming tight through direct tactile feedback on the rotary drive member without the interference of indexing mechanism torque requirements. Only after slack is fully removed does the indexing part engage to provide audible feedback during controlled tightening.
Solution Approach 2:
The system dynamically transitions between two operational modes: a free-spooling mode where the spool part rotates without indexing engagement to allow tactile feedback, and an indexed mode where the indexing part engages to provide audible feedback. This dynamic switching optimizes both tactile and audible feedback mechanisms for their respective functions.
3Productivity
If the indexing part is engaged early in the spooling process, then the tether can be tightened with feedback, but the spring stiffness degrades over time reducing holding torque
Solution Approach 1:
The slack removal process is completed in advance during the first configuration before the indexing part with springs is engaged. This eliminates the cyclic loading of the indexer springs during the potentially lengthy slack removal phase, preventing progressive degradation of spring stiffness and loss of holding torque while maintaining efficient titration through the subsequent indexed tightening phase.
Data Source
AI summary
A bone anchor for a tongue manipulation device which has a tissue anchor for attachment to the tongue, the bone anchor, for example for attachment to the mandible and a tether line which fixes the tissue anchor to the bone anchor. The bone anchor has a spool arrangement with a indexing part and a spool part. In a first configuration the spool part is operable to spool the tether line without operation of the indexing part, and in a second configuration the spool part is operable to spool the tether line with operation of the indexing part. This means the spooling to take up slack in the tether line does not cause wear to the indexing springs, and it also means the user can feel when the slack has been taken up.