Rotational HFCWO Pump Plunger Cam Mechanism
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Solution Overview
Problem
Generating high frequency oscillation force for chest wall therapy, such as for patients with mucus build-up like cystic fibrosis, is challenging due to the need for effective and efficient mechanisms to loosen and remove mucus from the upper respiratory tract.
Innovation Solution
A high frequency chest wall oscillation system comprising a therapy garment and a pump with a diaphragm bladder and plunger assembly that generates pressure oscillations through a drive shaft and cam mechanism, allowing for radial reciprocating motion of plungers to compress and expand the bladder, providing oscillating impact to the chest wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional HFCWO mechanisms are used, then chest wall oscillation can be achieved, but the device complexity and energy consumption increase
Solution Approach 1:
The pump chamber is divided into multiple segments with multiple plungers (e.g., three plungers arranged circumferentially) that independently compress the bladder. This segmentation allows distributed force application, improving oscillation efficiency while maintaining manageable device complexity through modular design
Solution Approach 2:
The drive shaft with cam mechanisms generates periodic reciprocating motion of the plungers, creating high-frequency oscillations. The cam profiles are designed to provide periodic compression and expansion cycles, achieving the required oscillation frequency (e.g., 10-20 Hz) while simplifying the overall mechanism compared to traditional piston-crank systems
2Reliability
If high frequency oscillation force is generated, then mucus removal efficacy improves, but the mechanism complexity increases
Solution Approach 1:
The pump generates mechanical vibrations through rapid reciprocating motion of plungers driven by cam mechanisms on a rotating drive shaft. This mechanical vibration is transmitted through the bladder to the chest wall, creating the high-frequency oscillations (10-20 Hz) needed to effectively loosen and remove mucus from the respiratory tract
Solution Approach 2:
A flexible bladder serves as the interface between the mechanical pump system and the patient's chest wall. The bladder expands and contracts in response to plunger compression, providing a compliant surface that distributes oscillation forces evenly across the chest wall while simplifying the mechanical coupling between the pump and therapy garment
3Productivity
If multiple plungers are used, then oscillation efficiency increases, but device complexity increases
Solution Approach 1:
Multiple plungers are merged into a single integrated plunger assembly that shares common structural elements, such as a shared drive mechanism through the cam-driven rotate shaft. The plungers are circumferentially arranged and driven simultaneously, combining their compressive forces to achieve efficient oscillation while reducing overall assembly complexity compared to independent plunger systems
Solution Approach 2:
The plungers are arranged circumferentially around a central drive shaft, creating a radially symmetric configuration. This spherical arrangement allows uniform force distribution and efficient conversion of rotational cam motion into radial compression, improving oscillation efficiency while simplifying the mechanical design through geometric symmetry
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 effectively loosens and removes mucus from the upper respiratory tract by applying repetitive force to the chest wall, improving expectoration and treatment efficacy for conditions like cystic fibrosis with reduced energy consumption and increased efficiency compared to traditional designs.
Implementation Method 1
The drive assembly may include a drive shaft extending along a rotational axis and a cam engaged with the drive shaft and the at least one plunger
Implementation Method 2
The at least one plunger may be coupled with the cam for radial reciprocating motion to compress the at least one diaphragm from one position to another position to generate pressure oscillations
Implementation Method 3
A high frequency chest wall oscillation pump may include an elastic diaphragm bladder defining a pressure cavity therein and arranged for resilient operation between an expanded state in which the pressure cavity has an expanded volume and a compressed state in which the pressure cavity has a compressed volume
Data Source
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AI summary
Devices, systems, and methods for high frequency chest wall oscillation pumps can include a pressure cavity, defined by one or more diaphragms, for fluid pressurization to provide pressure oscillation, a drive assembly can be arranged to provide reciprocation to a plunger assembly to move the one or more diaphragms to generate fluid pressure.