Compact Servo Lung for Manikin Integration
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Solution Overview
Problem
Existing servo lung devices are too bulky to fit inside a human manikin, limiting their use to external, stand-alone systems, and lack the capability to simulate realistic lung function, including non-linear response and spontaneous breathing.
Innovation Solution
A compact internal servo lung configuration with a selectively sealed chamber, a motor, an air intake, and a threaded member with self-lubricating plastic travelers and a piston, which allows for realistic lung simulation by adjusting the baseline position of the piston and manipulating compliance to expel constantly held volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional servo lung design (cylinder with piston and ball screw) is used, then the device can simulate lung function, but the device becomes too bulky to fit inside a manikin
Solution Approach 1:
The patent applies nesting by placing the piston, travelers, and lead screw mechanism inside a cylindrical chamber that fits within the manikin's thoracic cavity. The piston is nested within the chamber, and the lead screw is nested within the piston structure, creating a compact hierarchical arrangement that reduces overall device volume while maintaining functionality.
Solution Approach 2:
The patent transitions from a linear ball screw mechanism to a rotational lead screw mechanism, changing the dimensional approach to achieve compactness. The lead screw rotates within the piston, converting rotational motion to linear motion in a space-efficient manner that reduces the device's external dimensions while preserving the lung simulation capability.
2Volume of moving object
If the baseline volume of air is minimized to achieve compactness, then the device size is reduced, but the ability to simulate realistic lung conditions is compromised
Solution Approach 1:
The patent implements dynamics by making the piston's baseline position adjustable through the lead screw mechanism. The controller can dynamically reposition the piston to different baseline locations within the chamber, allowing the device to adapt to various lung conditions (normal, abnormal, post-operative) without requiring a larger fixed volume. This dynamic adjustment capability enables versatile simulation within a compact form factor.
Solution Approach 2:
The patent changes the parameter of piston position to control the baseline volume. By adjusting the piston's position along the lead screw, the system can vary the volume of air in the chamber to simulate different lung conditions. This parameter change approach allows the compact device to maintain adaptability across multiple simulation scenarios.
3Volume of moving object
If a compact design is implemented, then the device can fit inside a manikin, but the complexity of sealing and pressure control increases
Solution Approach 1:
The patent extracts the sealing function from a complex external sealing system and integrates it into the piston structure itself. The piston includes integrated seals that directly contact the chamber wall, eliminating the need for separate external sealing mechanisms. This extraction simplifies the overall device complexity while maintaining effective sealing in the compact design.
Solution Approach 2:
The piston serves multiple functions simultaneously: it acts as a moving wall to vary chamber volume, as a sealing element to maintain pressure differentials, and as a mounting structure for the lead screw mechanism. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity despite the compact constraints.
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 compact design enables the servo lung to fit inside a manikin, providing a realistic anthropomorphic training environment with improved tidal volume potential and the ability to simulate normal and abnormal lung conditions.
Implementation Method 1
A biasing member is added to the assembly to surround the second traveler and is secured by a lockring attached to the second traveler so that the biasing member biases against the lockring and the piston.
Implementation Method 2
A first traveler, second traveler, and piston are assembled along the threaded member. These self-lubricating plastic travelers are threaded to conform to the threading of the threaded member
Implementation Method 3
Other elements, such as an O-ring, grease, and/or formed seal and seal cover may be added to this device to seal between the pressurized and ambient compartments of the chamber.
Data Source
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Figure 3A
AI summary
A device for simulating a patient's lung in combination with a ventilator, manikin, or other external systems. A threaded member extends across a chamber of the device, having a piston and a two-traveler assembly thereon. The traveler assembly, in part, provides a seal between an ambient compartment at one end of the chamber and a pressurized compartment representing the simulated lung at an opposite end of the chamber having an air intake. Other elements, such as an O-ring placed between parts of the traveler assembly, grease added to the traveler assembly, and/or a formed seal and seal cover within the pressurized compartment further seal between the pressurized and ambient compartments of the chamber. The compact form of the device is aided by a volume compensation system which interacts with the external system, measuring air pressure and chamber volume to expel excess retained air from the pressurized compartment.