Locking Trocar Guide Sleeve Cam Mechanism
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Solution Overview
Problem
Conventional intramedullary nailing techniques lack the ability to quickly and reliably apply and release pressure during the locking of intramedullary nails to bone fragments, which complicates the alignment and attachment process.
Innovation Solution
A guide sleeve assembly combined with an aiming arm system that applies pressure to a bone plate and includes a cam mechanism with a retention element to secure the guide sleeve in place, preventing axial movement and ensuring accurate alignment and attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sleeves are used to expose target screw location and provide guidance, then drilling and screw insertion can be completed, but the ability to quickly and reliably apply and release pressure is lacking
Solution Approach 1:
The guide sleeve assembly incorporates a dynamic locking mechanism with a retention element that can transition between locked and unlocked states. The cam mechanism allows the guide sleeve to be quickly locked to the aiming arm to apply pressure, and just as quickly unlocked to release pressure, transforming a static connection into a dynamic one that responds to operational needs.
Solution Approach 2:
The retention element is extracted as a separate component from the guide sleeve assembly, allowing it to be independently manipulated to lock and unlock the guide sleeve to the aiming arm. This separation enables quick engagement and disengagement without moving the entire guide sleeve assembly.
2Manufacturing precision
If multiple sleeves are used for drilling and screw insertion guidance, then accurate positioning is achieved, but procedural complexity increases
Solution Approach 1:
The guide sleeve assembly merges multiple functions into a single integrated component: it provides alignment guidance for screw insertion, applies lateral pressure to the bone plate, and includes a locking mechanism to secure its position. This consolidation eliminates the need for multiple separate sleeves and simplifies the procedural steps.
Solution Approach 2:
The guide sleeve assembly is designed as a multi-functional tool that simultaneously performs alignment, pressure application, and positioning functions. The single assembly can be used for both drilling guidance and screw insertion guidance, reducing the number of different components needed in the procedure.
3Stability of the object's composition
If the guide sleeve assembly is designed with a locking mechanism, then position stability is improved, but device complexity increases
Solution Approach 1:
The cam mechanism in the locking assembly uses an asymmetric geometry where the cam surface is angled relative to the retention element. This asymmetric design allows for easy engagement (pushing the guide sleeve into place locks it) while requiring a different, more deliberate action for disengagement, providing stable locking with minimal complexity.
Solution Approach 2:
The cam mechanism is designed so that the natural insertion motion of the guide sleeve into the aiming arm automatically engages the locking mechanism. The geometry of the cam and retention element causes them to lock together as the guide sleeve is pushed home, eliminating the need for a separate locking action or additional components.
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 system enables precise and secure attachment of the bone plate to the intramedullary nail, facilitating efficient locking and reducing procedural complexity by providing consistent pressure and alignment.
Implementation Method 1
the sleeve guide creates a cam mechanism between a full outer diameter of the sleeve guide and the cross pin. This forms an interference fit between the outer sleeve guide and the cross pin, that produces enough friction between the sleeve guide and pin to substantially prevent axial movement of the sleeve guide in the guide hole.
Data Source
AI summary
An aiming arm system comprises an aiming arm and a guide sleeve. The aiming arm has 1) a body and a guide hole that extends through the body along a hole axis, and 2) a retention element supported relative to the body. The aiming arm is configured to be positioned such that the hole axis is aligned with a target location of an anatomical implant. The guide sleeve extends along a linear direction, and is sized to be inserted through the guide hole in the linear direction. Relative rotation between the guide sleeve and the retention element transitions the aiming arm system between an unlocked configuration whereby the guide sleeve is insertable through the guide hole, and a locked configuration whereby the retention element applies a retention force to the guide sleeve that substantially prevents the guide sleeve from moving further along the linear direction.