Medical Implant Locking Device Prevents Screw Backout
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Solution Overview
Problem
Existing bone fixation mechanisms in medical implants often experience issues with screws backing out from the receiving member, leading to instability and potential complications during surgical procedures.
Innovation Solution
A locking device with a secondary socket and radial detent mechanism that secures the fixation screws in place by rotating to a locked position, utilizing a cap with a resilient arm and positive stop to prevent axial motion, allowing for articulation while maintaining fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple bone fixation mechanism is used, then ease of operation is improved, but reliability deteriorates due to screws backing out
Solution Approach 1:
The locking device is divided into distinct functional segments: a resilient arm for engagement, a detent mechanism for positioning, and a positive stop for limiting motion. This segmentation allows each component to perform its specific function efficiently while maintaining overall simplicity of the fixation mechanism.
Solution Approach 2:
The locking device incorporates dynamic elements including a resilient arm that can deflect to accommodate screw insertion and removal, and a rotatable cap that transitions between locked and unlocked positions. This dynamic design maintains reliability while preserving ease of operation during surgical procedures.
2Reliability
If a locking device with multiple components is added, then reliability is improved by preventing screw backout, but device complexity increases
Solution Approach 1:
Multiple locking functions are merged into a single integrated device: the resilient arm provides both engagement and positioning, the detent mechanism combines locking and indication functions, and the cap integrates both protection and operation features. This merging reduces the number of separate components while maintaining high reliability.
Solution Approach 2:
The locking device performs multiple functions simultaneously: it prevents screw backout, allows controlled articulation, provides positional indication, and enables easy unlocking. This multi-functionality reduces the need for separate components, thereby improving reliability without proportionally increasing device complexity.
3Stability of the object's composition
If a locking mechanism with detent and positive stop is used, then stability is improved, but ease of operation deteriorates due to complex locking procedure
Solution Approach 1:
The resilient arm automatically engages with the screw head and the detent mechanism self-locks when the cap is rotated to the locked position. The positive stop automatically prevents over-rotation. These self-service features provide high stability while requiring minimal manual intervention, thereby maintaining ease of operation during the locking procedure.
Data Source
AI summary
A receiving member has a primary socket for a fixation mechanism and a secondary socket for a locking device. The secondary socket has a first bore intersecting a portion of the primary socket and forming an arcuate cut-out. The secondary socket has a chord member extending into the secondary socket first bore that forms a radial undercut in the secondary socket. The secondary socket has a detent extending from the radial undercut into the chord member. The locking device is rotatable in the secondary socket between an unlocked position in which an engagement surface of a cap of the locking device is angularly displaced from the arcuate cut-out, and a locked position in which the cap engagement surface occupies the arcuate cut-out and engages the fixation mechanism, and the arm engages an underside of the chord member, thereby preventing the fixation member from disengaging the receiving member primary socket.