GB835198A - Resuscitator mechanism - Google Patents

Abstract

835,198. Respirators. STANTON, P. L. Aug. 22, 1958 [March 24, 1958], No. 27081/58. Class 81 (2). Respiratory apparatus comprises a chamber connected to a gas supply and to the lungs, flow of gas through the chamber being controlled in response to pressures above and below atmospheric by a piston subjected on one side to atmospheric pressure and on the other to pressure in the chamber. Lower and upper sections la, 1b, Fig. 4, of a body 1 are separated by a gasket 3 and are secured inside a plastic cover 1c so that a chamber 5 open to atmosphere through an opening 6 is formed above the sections. Gas under pressure is supplied by a hose 21 to an intake passage 16, Fig. 8, and through a manually-adjustable needle valve 22 and a port 17 into a valve chamber 9. On inhalation, gas flows from the valve chamber 9 to a mask 2, Fig. 1, supported on the body 1 via a port 8 and a main chamber 7 in the lower section 1a. Negative and positive pressure safety valves 12, 13, Fig. 3, communicate with the main chamber 7. The valve chamber 9 also communicates via a passage 33 with a Venturi tube 28 so that gas can pass via a jet nozzle 34 and the throat 31 of the Venturi tube 28 to atmosphere to effect exhalation. A piston 39, which is reciprocable in a cylinder 38 formed in the upper body section 1b and is subjected to pressure in the main chamber 7, is secured to a spring toggle mechanism 41 in the chamber 5 which is open to atmosphere. One arm 47 of the toggle mechanism 41 is attached to a valve stem 40 having valve members 44, 45 controlling the passage of gas from the valve chamber 9 to the main chamber 7 and the Venturi tube 28 respectively. When the first valve member 44 is open gas is supplied to the chamber 7 and the lungs to effect inhalation, a small amount of gas passing from the main chamber 7 to atmosphere via a suction port 35 and the Venturi tube. Pressure builds up in the chamber 7 during the inhalation phase and on reaching a predetermined maximum moves the piston outwardly of the main chamber. The toggle mechanism 41 snaps over to close the first valve member 44 and open the second valve member 45, thus permitting gas to flow only into the Venturi tube 28 from the valve chamber 9. Gas from the main chamber 7 and the lungs is thus drawn through the suction port 35 to effect an exhalation. When the pressure in the main chamber reaches a predetermined minimum, the piston 39 is moved inwardly of the main chamber 7 to snap over the toggle mechanism and move the valve members 44, 45 into position for inhalation. If the gas supply is sufficiently restricted by the control valve 22, the pressure in the main chamber 7, which is vented continuously through the suction port 35, never becomes sufficiently great to operate the piston and the toggle mechanism to effect the closing of valve member 44. Thus the inhalation phase of operation of the device may be made continuous.