Final Design

1) Lever Hand Control

The spool lever offers a mechanical advantage, resulting in high torque to drive the tension wire system.
The dual-spools configuration enables control of two wires in opposing tension and compression states. Allow for bidirectional vertical motion.
Dimension: 35mm x 50 mm x 70mm
- Allow comfortable operation with only one hand.
Max displacement of single cable = 7.66 cm
Final Dimension choosed 24mm diameter spool, providing mechanical advantage of 1:2.

3D-print with carbon fiber
Provides rigidity and maintains the ideal curvature required for an endotracheal tube to perform intubation.
Houses the tension wire
Section 1 encases the tension wire.
Section 2 provides the curve, and also guide wire around the curve in a distinct position for proper alignment and attachment to the distal tip.
Section 2 where separated from section 1 to prevent overcontraint of ET tube, enable higher degree of deflection.

Made through 3D printed TPU
Evenly spaced grooves on both sides to enable the targeted deflection.
Actuated by two wires that are separately connected to different sides of the grooves.
Two small tunnel houses the wire in straight orientation.
Wires crimped in wire rope oval sleeve at end to prevent slipping.
Sleeve and wire heated with solder to sink into end of tip to reduce profile with tension pulling in.
External TPU is melted onto the remaining length of to protect scratching in tube or patient's airway.

Through ANSYS simulation, the force required to displace the endotracheal tube end by 20॰ is predicted to be 0.7 N. The minimum design goal is to achieve 0.7 N to meet the functional requirement.
With the prototype, the distal tip is able to exert force consistently between 1.7 and 2.0 N. The highest force reached 2.16 N. ANSYS simulation, resulting in 53॰ degree of deflection.
- Result: Higher force allow for deflection more than 20॰. However, the prototype cannot meet the 53॰ deflection and only achieved 40॰.
- Reason:
  - ANSYS simulation modeled a less stiff endotracheal tube that was used in actual procedure. While the endotracheal tube that was tested was used for training purposes.
  - The natural curve of the endotracheal tube resist the bending.

Being able to perform +40॰ and -5॰ from the rest position of the stylet. The Final Product covered 45॰ range of motion.
Such a motion is ideal for intubation, as there is often limited space for the doctor to hold up the stylet to enter the trachea and more space for the doctor to push the stylet down.

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