USRE23845E - Resuscitator - Google Patents

Description

H SEELER RESUSCITATOR June 29, 1954 Origihal Filed Feb. 26, 1951 I5 Sheets-Sheet 2 7'0 665 SOURCE To rec: MESA INVEN TOR. HENAEY 555156 H. SEELER RESUSCITATOR June 29, 1954 3 SheetsSheet 3 M m w w r 0 5 new f m M a P\ V 2 A O 3 nwU a I M w 3 6 K VH V m 3 U, m 7 a m m m 1 5 5 m w M .1 5 w r H E z |Y B 6 ll L 222 Z a, P M 5 6 m m w MM m a r I. T 6 E E g M H J mw INVENTOR. HENEY JEELEE as PATENT OFFICE BESUSCITATOR Henry Seeler, Dayton, Ohio Original No.

2,581A50, dated January 8, 1952, Se-

rial No. 212,818, February 26, 1951. Reissue No. 23,496, dated May 20, 1952, Serial No. 271,841, February 15, 1952. This application for reissue May 26, 1953, Serial No. 357,653

(Granted under Title 35, U. s. Code (1952).

- sec. 266) 19 Claims.

Matter enclosed in heavy brackets the first and this reissue specification; the first reissue; matter printed made by this reissue.

The invention described herein may be manufactured and used by or for the United States Government ior governmental purposes without payment to me of any royalty thereon.

The present invention relates to a resuscitator or artificial respiration device of simple, compact and reliable construction.

The primaryobject of the invention is to provide a resuscitator of the kind which includes an aspire-tor into which flows a gas under pressure suitable for use in resuscitating human patients and wherein a crank actuated butterfly valve within the aspirator is automatically moved from an open position to a closed position and vice verse. by the action of a pressure responsive means coupled to an overcenter spring means associated with the crank actuated valve, whereby the valve when open allows gas to flow through the aspirator to produce a suction eflect and when closed causes gas to flow laterally from the aspirator to produce a pressure effect.

A further object of the invention is to provide a resuscitator of the kind which includes an aspirator or Venturi tube into which flows a. gas under pressure suitable for use in resuscitating human patients, wherein a butterfly valve in the -aspirator downstream from a lateral opening therein is rigidly connected to a simple crank operating means, wherein a coil spring connected to the crank operating means is actuated by a slidably mounted rod fixed 'to a diaphragm, wherein adjustable compression springs are provided at opposite ends of the slidably mounted diaphragm actuated rod and wherein a. gas flow channel in the resuscitator is in communication with the lateral opening in the aspirator, with a tube leading to a face mask and with one side of the rod-actuating diaphragm, whereby the butterfly valve when brought to open position by thediaphragm and slidably mounted rod acting through the coil spring and crank operating means functions to produce the exhalation phase of the resuscitation cycle and when brought to closed position functions to produce the inhalation phase of the resuscitation cycle.

Another objector the invention is to provide a resuscitator system including a face mask and associated resuscitator which receives its supply of gas from a pressurized oxygen source or from a blower operated by an impulse turbine, and wherein the turbine operates by the inflow of atmospheric air by virtue of negative back pressure on the turbine achieved by use of a simple Jet pump operable by a water tap. 4

[1 appears in the original patent but forms no part of matter printed in italics indicates the additions made by in bold face (except reference figures) indicates the additions Another object of the invention is to provide a resuscitator of the kind which includes an aspirator or Venturi tube into which flows a gas under pressure and including a control valve in the aspirator located downstream from a lateral opening therein and wherein the control valve is operable automatically by a simple and reliable mechanism actuated by a pressure responsive diaphragm.

The above and other objects of the invention will become apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:

Fig. 1 is a top plan view of the present resuscitator looking down on the gas lead-in connection and regulating means associated therewith.

Fig. 2 is a vertical cross sectional view taken on the line 2--2 of Fig. 3.

Fig. 3 is a transverse cross sectional view through the resuscitator and showing the aspirator in longitudinal cross section.

Fig. 4 is a longitudinal cross section.. taken through the aspirator and associated control 4 valve.

Fig. 5 is a schematic view of resuscitator and associated components comprising a possible system for general use in hospitals, aid stations and related installations.

RESUSCITATOR CONSTRUCTION Referring to Figs. 1 to 4 of the drawings the resuscitator will be described in detail. The main body i is of generally cylindrical shape and is closed at one end by a screw threaded cap or cover plate 2 having small openings 3 therein. An annular shoulder within the body provides a seat for a circular wall member 4, a circular diaphragm I and a circular gasket 6 in series and these elements are retained by the screw cap 2. The wall member 4 includes a cylindrical extension I having its rim edge seated in a shallow groove formed in the body i at 8. Outwardly of the extension I the wall member 4 is pierced by a series of openings 9. A small cylindrical boss ill at the center of the wall member 4 provides a guide for a slidable valve actuating rod or stem l2 extending through the center of the diaphragm and rigidly fixed to a pair of diaphragm supporting plates or disks II. At oppodte ends of the rod I! are similar compression springs l4 and ii to provide light resistance to endwise movement of the rod II. The adjust- 3 ing means for the springs II and It are identical, so that only one such adjusting means need be described. Adiacent to the spring II the screw cap 2 is provided with a cup-like extension I,

having opposite slots l1 extending through a substantial part of the circumference and receiving a transverse pin II, the oppomte ends of which are anchored in a rotatable knob I! litting over the extension or boss ll. Ball detents 2|! in the'walls of the knob-bear on screw cap 2 to give frictional adjusting action to the knob as the detents snap into suitable indentations. Slidably mounted in the hollow extension II is. a spring abut'ment member 2| having opposite and similar cam portions 22 which cooperate with transverse pin ll so as and outward movement of the spring abutment member as the knob II is rotated. As seen in Figs. land 2 the knob l9 carries a pointer II which may be set with respect to suitable indicia to indicate the pressure response of the resuscitator as it cycles back and forth between suction and pressure phases of the resuscitation cycle. A suitable pin or other spline element 23 may be provided to maintain the abutment member 2| in non-rotatable relation with respect to hollow extension or boss II. The compressiveeffect of spring I 5 determines the maximum positlve pressure applied to the patient during the inhalation phase of the resuscitation cycle, while the compressive eflect of spring it determines the minimum negative pressure which obtains in the exhalation phase of the cycle. Suggested pressure ranges for these phases are 0 to +8 inches of water for the inhalation phase and 0 to 3 inches of water for the exhalation phase. Suitable indicia adjacent to the spring adjusting knobs provide a calibrated scale for them pressure ranges. The

01' the gas reaching the fitting 2| will usually be held to the maximum positive pressure used in to produce inward nite gas channel maximum inlet pressure resuscitation, for example about +10 inches or water.

Referring to Figs. 3 and 4, there is shown an aspirator assembly which extends through the main body I at one side of a central location and coaxial with respect to the gas inlet fitting 26 and a gas outlet or discharge passage 21. The aspirator includes a tube 28 having an annular flange 28 at the inlet end seated against an annular shoulder in the resuscltator body I. Seated on the flange 29 is a flanged nozzle element 32 and the contacting flanges are held in place as shown by a threaded ring ll which includes wrench-receiving radial slots. The interior of the tubular member 28 is of flared cross section to provide a diifuser section in the asplrator extending almost to the outlet of nozzle ll. Laterally opening gas ports 32 in the tube 28 adjacent to the outlet of nozzle provide communication to the interior of body I and particularly to an annular space between the wall member I and the end wall of body I remote from the diaphram 5 (see Fig. 2). A butterfly valve 33 in the tube 28 is rigidly connected to a crankshaft 34 having an oifset end situated at one side of the rod l2 and connected thereto by an actuating spring 85. As the rod I2 is shuttled back and forth by action of the diaphragm I, the spring 35 moves from one side to the other of the axis of rotation of crankshaft ll thus causing the valve 33 to snap to open or closed posi-v tion with a sudden movement (see Fig. 2). The solid line positions of the spring, crankshaft and bular fitting 38.

face mask.

'44 adapted groove in fltting 2t 4 valve correspond to the open position of the valve wherein the aspirator 2| is effective to pull a vacuum in the annular space leading to the tu- This brings about the exhalation phase of the resuscitation cycle, since the fitting it normally carries a tube-leading to the When the valve II moves-to closed position, the gas from nozzle it can only spill out through ports 32 to provide positive gas flow through fitting II to the face mask. The annular wall portion I provides means to form a deflfrom the ports 32 to the fitting 36 and vice ve This protects the moving parts, such as stem I2, spring I! and crankshaft 24 from moisture exhaled from the patients lungs. One objection to moisture as it relates to moving parts is the danger of freezing up at low temperatures. The operation will be more fully described below.

The outlet end of tube 2. extends into a flanged tubular element 31 having removable liner II which carries a screen 38 across the outer end to prevent foreign bodies and extraneous material, such as packing, from entering the. resuscitator. The fltting 2| for connection with a source of gas under pressure, such as a cylinder of oxygen, has mounted therein a flow regulating valve comprising a transverse rod ll extending into longitudinal slots ll in the fltting 26 and also into similar cam slots 42 in the rotatable collar ll. The rod ll carria a tapered valve member to enter the outer end of nozzle II and thus regulatethe size of the annular passage between the valve member and the nomle .opening. A

pair of screws ll threaded into the collar ll have inner ends riding in a circular ment of collar 43 but still permit free rotation thereof. A pointer 48 on the collar 41 serves to indicate by its position with relation to the scale A ll, the flow rate through the regulating valve and into tlie nozzle 30. The suggested scale of values for the flow rate is from 0 to liters per minute. Ordinarily the valve will only be closed completely when the resuscitator is not in use but the wide range of flow rates will adapt the device for use on people of all ages and all possible basic metabolic rates. Furthermore the flow rate in any given case will determine the cycling rate of the resuscitator, since the rate of gas flow will determine how fast the patients lungs fill to capacity andhow fast the patient's lungs are emptied of gas, moisture and waste products.

RESUSCTIATOR OPERATION that the setting of spring II will effectively determine how low the pressure goes before the coil spring II swingsto the right past the, crank arm I4 and causes the crank arm and the valve 33 to snap to the valve closing position and start the inhalation or positive pressure phase of the resuscitation cycle. New with the valve 3! closed to. prevent endwise move valve actuating diaphragm I the incoming gas will fiow from ports 32 into the resuscitator body and thence around the flow channel previously described to the outlet fitting 3B. As the patients lungs fill up with fresh gas the positive pressure in the resuscitator will slowly increase to cause the diaphragm Ii to move toward the left, thus moving the rod i2 and bringing the overcenter coil spring 35 to the dotted line position with the crank arm Bl still in the dotted line or valve closed position. Now the compression spring ll is no longer producing any appreciable endwise pressure on the rod l2 but the positive pressure spring I5 is resisting further movement 01' the rod it toward the left. Thus it will be seen that the setting of spring II will determine how high the pressure goes before the coil spring 35 swings past the crank arm 84 and causes the crank arm and valve 83 to snap to the valve opening position and thereby start the exhalation or negative pressure phase of the resuscitation cycle. The spring 35 is shown in two positions, each approaching the critical snap-over relation, with respect to the crank arm 34 (see Fig. 2). The crank arm is shown in its two extreme positions, the lull line position being the valve open position (see Figs. 2, 3 and 4) and the dotted line position being the valve closed position. In the first position, the contact of the arm and wall 4 provides a definite stop action and in the second position the contact of the valve 3: with the walls or tube 28 provides a definite stop action. As noted previously the adjustable inlet valve determines the flow rate for a given subject and also determines at the same time the cycling rate or the resuscitator. In practice a table oi! values is furnished with the resuscitator to show the desired setting of the inlet valve ior people 0! various ages and more particularly for people of various sizes. In some cases the values are varied from the normal, as for instance in applying the resuscitator to persons who have absorbed noxious fumes. Here a higher flow rate will aid in eliminating from the blood some oi the undesirable dissolved gases. While the exhalation phase oi the resuscitation cycle will preferably proceed until there is a slight negative pressure in the device, this practice is not always recommended. Some authorities do not recommend the use of negative pressures in resuscitation or artificial respiration because of the tendency to cause adhesion of lung" tissues and partial collapse of bronchial tubes.

nnsoscrrs'rron SYSTEM Referring now to Fig. 5 there is shown one possible resuscitation system or hook-up of general application. The resuscitatior as described above is shown in exterior end view showing the spring adjusting knob I! mounted on the screw cap 2. The fitting 36 is connected to the face mask III, which is adapted to fit over the mouth and nose of the patient and may be held in place by hand or by suitable straps. At the race contacting edges or the mask there is provided a flexible tube ll connected to the interior of the mask by means 01 a one-way valve l2, arranged so that the maximum pressure in the mask will be developed in the tube II but will not leak back into the mask.

The gas inlet fitting 28 is connected to a conduit BI connected through a shut-ofl valve 54 and pressure relief valve II to a blower I. The latter is provided with an air inlet screen 31 and the rotor I8 is mounted on a shaft-I0 ex-' tending into an adjacent impulse turbine unit 80. The shaft ll! also includes a non-circular end portion 6| which may be connected in an emergency to an electric motor or other power source in case the motive-power for the turbine fails. In normal operation the turbine 00 is operated by atmospheric air entering at the nozzle 62- and impinging on the turbine rotor II. The flow of atmospheric air against the turbine wheel is brought about by connecting the turbine casing to a jet pump II or other vacuum pump. The jet pump is operated by passing-a stream or water therethrough from a water tap 64 and the water after passing out or the pump flows into a suitable drain or sink II. Asecond source or gas is conducted into the tube 51 by a conduit connected by way or a shut-off valve II and a reduction valve 61 to an oxygen tank or bottle 88. As will be understood the oxygen may be under very high pressure in the bottle 68 and in order to bring the pressure at the resuscitator inlet 28 down to about +10 inches of water there must be provided an eificient reduction valve preferably mounted directly on the outlet tube of tank or bottle 83.

The system illustrated in Fig. 5 should afi'ord reasonable safety because of the alternative sources of resuscitating gas. In the illustration, the source of compressed air from blower U6 is connected to the resuscitator since the valve 54 is open at the same time the valve 66 is closed. The pressure relief valve 55 near the blower is for the purpose of maintaining a predetermined maximum pressure in the conduit 53, for instance about +10 inches of water. While pure oxygen having a minor percentage of carbon dioxide mixed therein is the preferred gas, compressed air will always provide a satisfactory substitute. In some cases carbon dioxide is added continuously to the flowing oxygen from a separate bottle equipped with a metering valve.

The embodiment of the invention herein shown and described is to be regarded as illustrative only and it is to be understood that the invention is susceptible of variations, modifications and changes within the scope of the appended claims.

I claim:

1. A resuscitator comprising, a housing defining a gas receivin chamber, said housing being provided with a port adapted for connection with a mask, conduit means traversing said chamber, said conduit means being fitted at one end for attachment to a source of gas under pressure and the other end thereof defining a discharge port open to the ambient atmosphere, jet pump means within said conduit means and including a nozzle and an adjacent constriction spaced downstream from the nozzle, a rotatably mounted valve positioned between said constriction and said discharge port for opening and closing said conduit means, a crankshaft rigidly connected to said valve and extending outside of said conduit means, a valve actuating diaphragm in said housing communicating at one side with said gas receivin chamber, a slidably mounted rod secured centrally or said diaphragm, spring means extending laterally from said rod and connected to said crankshaft, port means in said conduit upstream from said constriction and connecting with said gas receiving chamber, whereby gas flowing into said conduit will alternatcly flow through said port means and t0 the lungs of a patient wearing said mask or fiow through said iet pump means to the ambient atmosphere as said valve is closed or opened respectively by action of said diaphragm. rod. spring means and crankshait.

'2. A resuseitator comprising, a housing defining a gas receiving chamber, said housing being provided with a port adapted for connection with. a mask, conduit means traversing said chamber, said conduit means being fitted at one end for attachment to a source of a gas under pressure and the other .end thereof defining a discharge port open to the ambient atmosphere, Jet pump means within said conduit means and including a nozzle and an adjacent constriction spaced downstream from the nozzle, arotatably mounted valve positioned between said constriction and said discharge port for opening and closing said conduit means, acrankshaft rigidly connected to said valve and including a crank arm portion outside of said oonduit means, a valve actuating diaphragm in said housing communicating at one side with said gas receiving chamber, a slidably mounted rod secured centrally of said diaphragm and extending at a right angle with respect to said crankshaft, a coil spring connected between said rod and said crank arm portion and adapted to swing past said crankshaft to two opposite overcenter positions as said rod reciprocates by action of said diaphragm and as said valve is moved to closed and open positions, port means in said conduit upstream from said constriction and connecting with said gas receiving chamber, whereby gas flowing into said conduit will alternately fiow through said portmeansandtothelungs ofa patient'wearing said mask or flowthrough said jet pump means to the ambient atmosphere as said valve is closed or opened respectively by action of said diaphragm, rod, spring and crankshaft.

3. A resuscitator comprisinga housing defining a gas receiving chamber, said housing being provided with a port adapted for connection with a mask, conduit means traversing said chamber, said conduit means being fitted at one end for attachment to a source of gas under pressure and the other end thereof defining a discharge port open to the ambient atmosphere, Jet pump means within said conduit means and including a nozzle and an adJacent constriction spaced downstream from the nozzle, a rotatably mounted valve positioned between said constriction and said discharge port for opening and closing said conduit means, a valve actuating diaphragm positioned transversely oi said hous- 8. a perforate transverse wall in said housing spaced from said diaphragm and having a tubular extension enga ing one end of said housing away from said diaphragm, a rod slidably mounted through said transverse 'wall and extending axially through said tubular extension. means for securing said rod centrally of said diaphragm, a crankshaft rigidly connected to said valve and extending outside of said conduit 65 means within said tubular extension, spring means connected between said rod and said crankshaft for actuating said valve from closed to open position and vice versa upon sliding movement of said rod in opposite directions, and port means in said conduit means upstream from said constriction and connecting with said gas receiving chamber.

55 action of rising fining a gas receiving chamber, means provi a gas inlet into said housing, means providing a gas outlet from said housing into the ambient atmosphere, means providing a fitting on a wall of said housing connecting with said chamber and adapted for connection with a mask, an aspirator extending across said housing from said gas inlet to said gas outlet and including spill ports opening laterally from the aspirat'or into 10 said gas receiving chamber, a rotatably mounted valve in said aspirator downstream from said ports, a crankshaft rigidly connected to said valve and extending outside of said aspirator, a slidably mounted rod in said housing extending at a right 16 angle to said crankshaft, spring means extending laterally from said'rod and connected to said crankshaft to assume overcenter positions at opposite sides of said crankshaft as said valve is moved from closed to open positions, means 20 responsive to changes in pressure in saidchamher for moving said rod in opposite directions as thepressureinsaidchamberrisesandfalls. whereby a supply of gas flowing to said gasinlet will alternately fiow thro liih said ports and to the lungs of a patient wearing said mask or fiow through said aspirator to the ambient atmosphere as said valve is closed or opened rupeetively.

5. A resuscitator as recited in claim 4, and

further comprising, separate adjustable spring means bearing on opposite ends of said slidably mounted rod.

6. A resuscitator comprising, a housing defining a gas receiving chamber, means providing a gas inlet into said housing, means providing a gas outlet from said housing into the ambient atmosphere, means providing a fitting on a wall of said housing connecting with said chamber and adapted for connection with a face mask,

40 an aspirator extendingacross said housing from said gas inlet to said gas outlet and including spill ports opening laterally from the aspirator into said gas receiving chamber. a movably mounted valve in said aspirator downstream from said ports, valve operating means connected to said valve and extending outside oi said aspiraior, a slidably mounted rod in said housina'. means responsive to changes in pressure in said chamber for moving said rod in opposite directionsasthepre ureinsaidchamberrisesandfalls, spring mea connected between said valve operating means d said rod to actuate said valve from closed to open position and vice versa as said rod is moved in opposite directions by the and falling pressure in said chamber, and separate adjustable [spring] biasing means at opposite ends of said rod for biasing said rod in opposite directions.

7. A resuscitator comprising, a housing delinw ing a gas receiving chamber, means providing a gas inlet into said housing, means providing a gas outlet from said housing into the ambient atmosphere, means providing a fitting on a wall of said housing connecting with said chamber and adapted for connection with a face mask, an aspirutor attending across said housing from said gas inlet to said gas outlet and including spill Ports Opening laterally from the uspirator into said gas receiving chamber, a movably mounted valve in said aspirator downstream from said ports, valve operating means connected to said valve and extending outside of said aspirator, a Wot-ably mounted means in said 4. A resuscitator comprising, a housing dehousing, means responsive to change: inpre'uure pressure in said chamber rises and falls, means connected between said valve operating means and said reciprocably mounted means to actuate said valve from closed to open position and vice versa as said reciprocably mounted mean 18 moved in opposite directions by the action of risin and falling pressure in said chamber, and separate adjustable biasing means acting in opposition on said reciprocably mounted means for biasing the latter means in opposite directions.

8. A resuscitator comprising a housing defining a gas receiving chamber, means providing a fitting on a wall of said housing connecting with said chamber and adapted for connection with a face mask, an aspirator assembly associated with said housing, said aspirator assembly having a gas inlet and a gas outlet opening into the ambient atmosphere, said aspirator assembly having an opening forming a spill port opening laterally into said gas receiving chamber, a movably mounted valve in said aspirator assembly downstream from said ports, valve operating means connected to said valve and extending outside of said aspirator assembly, a reciprocably mounted means in said housing, means responsive to changes in pressure in said chamber for moving said reciprocably mounted means in opposite directions as the pressure in said chamber rises and tails, means connected between said valve operating means and said reciprocably mounted means to actuate said valve from closed to open position and vice versa as said reciprocably mounted means is moved in opposite directions by the action oi. rising and ialling pressure in said chamber, and separate adjustable biasing means acting in opposition on said reciprocably mounted means for biasing the latter means in opposite directions.

9. A resuscitator comprising a housing forming a gas receiving chamber, 'a diaphragm extending across the chamber in the housing dividing the housing into compartments, means for sealing the margins of the diaphragm to the walls of the housing, air intake ports for connecting one of said compartments to the ambient air, the other compartment having an opening fitting on the wall oi'said housing connecting said opening with a face mask, aspirator means associated with said housing, said aspirator means having a gas inlet and a gas outlet opening into the ambient atmosphere, said aspirator means having an opening forming a spill port and communicating with said gas receiving chamber, a movably mounted valve in said aspire-tor means downstream from the inlet opening and the spill port, means operated by the diaphragm moving in response to changes in pressure in said chamber i'or actuating the valve from open to closed position and vice versa, adjustable means accessible from the exterior of the housing for changing the pressure required to actuate the valve, and adiustable biasing means acting in opposition on said diaphragm for biasing the latter in opposite directions.

10. A resuscitator comprising a housing forming a gas receiving compartment, a diaphragm forming one wall oi the compartment, means for sealing the margins of the diaphragm to the walls of the housing, the side of the diaphragm opposite the compartment being exposed to ambient atmospheric pressure, the compartment having openings, a fitting on the wall of said housing connecting one of said openings with a face mask, aspirator means associated with said housing, said aspirator means having a gas inlet and a gas outlet opening into the ambientatmpsphere, said aspirator means having an opening forming a spill port and communicating with said gas receiving compartment, a movably mounted valve in said aspirator means downstream from the inlet opening to the spill port, means operated by the diaphragm moving in response to changes in pressure in said compartment for adjusting the valve from open to closed position and vice versa, means for restraining the movement of said last mentioned means preventing adjustment of the valve from open to closed position and vice versa until predetermined pressure differentials have been established between the ambient atmospheric pressure and the pressure of the gas in the compartment, and means accessible from the exterior of the housing for adjusting said restraining means so as to cause the valve to be adjusted in response to predetermined pressure differentials.

.11. A resuscitator comprising a housing forming a gas receiving compartment, a diaphragm forming one wall of the compartment, means for sealing the margins of the diaphragm to the walls of the housing, the side of the diaphragm oppo site the compartment being exposed to ambient atmospheric pressure, the compartment having openings, a fitting on the wall of said housing connecting one of said openings with a face mask, aspirator means associated with said housing,

said aspirator means having a gas inlet and a' gas outlet opening into the ambient atmosphere, said aspirator means having an opening forming a spill port and communicating with said gas receiving compartment, a movably mounted valve in said aspirator means downstream from the inlet opening to the spill port, means operated by the diaphragm moving in response to changes in pressure in said compartment for adjusting the valve from open to closed position and vice versa, means for restraining the movement of said last mentioned means preventing adjustment of the valve from open to closed position and vice versa until predetermined pressure differentials have been established between the ambient atmospheric pressure and the pressure of the gas in the compartment, and means accessible from the exterior of the housing for adjusting the restraining means so as to cause the valve to open in response to predetermined increase in the pressure in the compartment above atmospheric pressure.

12. A resuscitator comprising a housing forming a gas receiving compartment, a diaphragm i'orming one wall of the compartment, means for sealing the margins of the diaphragm to the walls of the housing, the side of the diaphragm opposite the compartment being exposed to ambient atmospheric pressure, the compartment having openings, a fitting on the wall of said housing connecting one oi said openings with a face mask, aspirator means associated with said housing, said aspirator means having a gas inlet and a gas outlet opening into the ambient atmosphere, said asjprator means having an opening forming a spill port and communicating with said gas receiving compartment, a movably mounted valve in said aspirator means downstream from the inlet opening to the spill port, means operated by the diaphragm moving in response to changes in pressure in said compartment for adiusting cases i l the valve irom open to closed position and vice versa, means for restraining the movement of said last mentioned means preventing adjustment of the valve i'rom open to closed position and vice versa until predetermined pressure ditferentials have been established between the ambient atmospheric pressure and the pressure,

of the gas in the compartment, and means messible from the exterior of the housing for adjusting the restraining means to cause the valve to "close in response toa predetermined decrease in pressure in the compartment below atmospheric pressure.

13. A resuscitator comprising a housing forml l a gas receiving compartment, one wail of the compartment consisting of a movably mounted diaphragm, the side of the diaphragm opposite the compartment being exposed to ambient atmospheric pressure, the compartment having openings, a fitting on the wall of said housing connecting one of said openings with a face mask, aspirator means associated with said housing, said aspirator means having a gas inlet and a gas outlet opening into the ambient atmosphere, said aspirator means having an opening forming a spill port and communicating with said gas receiving compartment, supporting means carried by the housing, a movably mounted valve in said aspirator means downstream from the inlet opening to the spill port, means mounted upon the supporting means and operated by the diaphragm moving in response to changes in pressure in said compartment for adjusting the valve from open to closed position and vice versa, means for restraining the movement of said last mentioned means preventing adjustment of the valve from open to closed position and vice versa until predetermined pressure diilerentials have been established between the ambient atmospheric pressure and the pressure of the gas in the compartment, and means for adjusting the restraining means to cause the valve to close in response to a predetermined decrease in pressure in the compartment below atmospheric pressure.

14. A resuscitator comprising a housing forming a gas receiving compartment, one wall of the compartment consisting of a movably mounted diaphragm, the side oi the diaphragm opposite the compartment being exposed to ambient atmospheric pressure, the compartment having openings, a fitting on the wall of said housing connecting one of said openings with a face mask, aspirator means associated with said housing, said aspirator means havin a gas inlet and a gas outlet opening into the ambient atmosphere, said aspirator means having an opening forming a spill port and communicating with said gas receiving compartment, supporting means carried by the housing, a movably mounted valve in said aspirator means downstream from the inlet opening to the spill port, means mounted upon the supporting means and operated by the diaphragm moving in response to changes in pressure in said compartment for adjusting the valve from open to closed position and vice versa, means for restraining the movement of said last 'mentioned means preventing adjustment of the valve from open to closed position and vice versa until predetermined pressure diilercntials have been established between the ambient atmospheric pressure and the pressure oi the gas in the chamber, and means tor adjusting the restrainingmeanssoastocausethevalvetoopenin response to predetermined increase in the pres- '12 sure in the compartment above atmospheric pressure.

15. The combination including a gas receiving chamber, a venturi tube into which a gas under pressure ilows, said venturi tube having a lateral openin communicating with the gas receiving chamber, a valve mounted in the venturi tube downstream from the lateral opening, and means for opening and closing the valve so that when the valve is closed the gas flows into the chamber andwhen open withdraws gas from the chambu, said means including a pressure responsive diaphragm forming one wall of the chamber, a rod connected to the diaphragm, adjustably mounted biasing means for restraining movement of the diaphragm when the valve is open, and biasing means for restraining the movement of the diaphragm when the valve is closed, and means connected to the rod for actuating the valve to open and closed positions when the pressure of the gas overcomes the restraining forces exerted upon the diaphragm.

16. The combination according to claim 15, wherein adjustable means are mounted in the Venturi tube for adjusting the gas inlet passage to the venturi tube for controlling the timing of the operation oi said val 17. The combination including a gas receiving chamber, a Venturi tube into which a gas under pressure flows, said venturi tube having a lateral opening communicating with the gas r chamber, a valve mounted in the Venturi tube downstream from the lateral opening, and means for opening and closing the valve so that when the valve is closed the gas flows into the chamber and when open withdraws gas from the chamber, said means includin a pressure responsive diaphragm forming one wall oi the chamber, a rod connected to the diaphragm, biasing means for restraining movement of the diaphragm when the vaiveis open, and adjustably mounted biasing means for restrainin the movement of the diaphragm when the valve is closed, and means connected to the rod for actuating the valve to open and closed positions when the pressure of the gas overcomes the restraining forces exerted upon the diap ragm.

18. The combination including a iluid receiving chamber, pressure responsive means mounted in one wall of the chamber, which a fluid under pressure ilows, said venturi having a lateral opening communicating with said chamber, a valve mounted in the venturi downstream from the lateral opening, means actuated by the pressure responsive means for opening and closing said valve, so that as the pressure of the fluid in the chamber reaches a predetermined pressure the valve is opened and so that as the pressure in the chamber drops to a predetermined pressure the valve is closed, and adjustabiy mounted biasing means accessible from the exterior oi the chamber for restraining the movement oi the pressure responsive means thereby to control the pressures at which the valve is opened and closed.

19. A resuscitator comprising a gas receiving chamber, prasure responsive means mounted in one wall of the chamber, aspirator means associated with said chamber, said aspirator means having a gas inlet and a gas outlet opening into the ambient-atmosphere, said aspirator having an opening forming a spill port opening laterally into said gas receiving chamber, a movably mounted valve in said aspirator means, said valve a venturi tube into 98,845 13 14 being located dovrnatream mm the spill port, in the can receiving chamber, the adjustment of valve operating means ccnneeted to said valve the biasing means ehanrln: said limits. and extendin: cntaide of said amiiator Ineanl,

actuating mean! actuated by said pressure rem m me of sponaive mean: to open and close the valve, and 5 or the original patent adjustable biaain means accessible from the 03- UNITED STATES PATENTS terior of the chamber for restraining the movement of the preelure responsive means lo a to Number NW Date ml he mnment of the m mum-e 3.536.435 FOX 1951 meanawlthinumandlomlimitaofpreaaurea 10'

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