A Novel Multi-Patient Mechanical Ventilator Drive System Using Continuously Variable Transmission and Reverse Gearbox

Abstract

In the present study, a new model of multi-mechanical ventilator drive using a continuously variable transmission (CVT) cone was presented as the main driving force to control the pressure of the BVM Ambu bag, which can produce different airflow pressures for several patients, and using a worm gear to isolate the CVT cone so as not to get the load generated from the pressure of the Ambu bag. In addition, the reverse gear transmission system is used to control the direction of rotation, and the leadscrew is used to change the rotation according to the linear translational motion of the Ambu bag pushing arm. In this system, a DC motor is used as the main driver, and a flexible tuner cable that can be connected to other ventilators is utilized. This research shows that this CVT system can reduce rotation down to 60.35% and increase rotation up to 148.26% with constant rotation input. There are 23 points of change in the position of the belt, which causes variations in the pouch pressing. The system can produce the highest and lowest pressure value at 20.2 and 0.4 cm H₂O. Simultaneously, the rotation of the flexible tuner cable showed no significant change. However, the weakness in the CVT system is the belt friction with the cone surface causing heat and slippage. In this case, the selection of the appropriate material and belt shape can cause belt displacement easiness that important in appropriate speed for applied pressure.