MECHANICAL
The mechanical design follows MIT E-Vent two-fingers design
Design Requirements
The basic concept consists of two arms that gently close in sync to compress the bag. This is coupled with a closed-loop control system with the following design specifications:
- Intended use: Two-week operation minimum: approximately 1 million cycles, 100% duty.
- Fail-Safe operation – If the machine fails, a clinician must be able to immediately shut down, open the device manually, remove the bag and convert to manual bagging.
- Gear (bottom of arms): 16 pitch, 48 tooth, 3 in. pitch dia., 14.5° pressure angle, 0.25 in thick.
- Pinion Gear (driving): 16 pitch, 30 tooth, 1.875 in. pitch dia., 14.5° pressure angle. 0.5 in thick – this is to accommodate axial misalignment with the arms’ gears.
- Gear Ratio: 1.6 (arm/pinion)
- Net radial load (F) on the pinion = 550 N - (Pending Testing)
Major Components
Power Requirements:
- Power (airway) = 10.46 W
- Power (gripper) = 20.92 W
- Power (motor) = 2 Power gripper = 41.48 W
Motor Specifications:- PLC: Rockwell Automation CompactLogix 5370
- HMI: Rockwell Automation PanelView 800, 4.3 in
- AC/DC breakers, power supply and additional components from Rockwell Automation
- Stepper Motor with Encoder: 24VDC Ethernet (AMCI)
- Input Voltage: 24 to 80 Vdc Motor
- Current: 5.4 Amp/phase
- Package Size: NEMA 34
- Holding Torque: 450 oz-in to 1100 oz-in Encoder: Incremental
Pressure Sensor- Solid-State Pressure Sensor, Standard, Non-Display, Transmitter, 0 psi (0 bar), 1/4 NPT Male, 60 psi (4.13 bar), Gauge, 4-20 mA Analog Only, 4-Pin DC Micro(M12),
Bag Sizing
The A3B is compatible with existing manual resuscitators bag sizes. The key design criteria are to provide mechanical adjustment to set up the A3B to optimal adjustment points on each bag that provide support and lateral constraint but do allow the bag to flex as it is compressed. The bag should be centered laterally and vertically between the grippers.
