US2845061A

US2845061A - Devices for facilitating breathing and producing artificial respiration

Info

Publication number: US2845061A
Application number: US511501A
Authority: US
Inventors: Goodner Monroe Harry
Original assignee: Stephenson Corp
Current assignee: Stephenson Corp
Priority date: 1955-05-27
Filing date: 1955-05-27
Publication date: 1958-07-29
Anticipated expiration: 1975-07-29
Also published as: FR1153362A; DE1100232B; GB813438A

Description

July 29, 1958 H. GOODNER 2,845,061 DEVICES FOR FACILITATING BREATHING AND PRODUCING ARTIFICIAL RESPIRATION Filed May 27, 1955 2 Sheets-Sheet 1 INVENTOR.

Monroe Hurry Goodner ATTORNEYS July'29, 1958 M. H. GooDNER 2,845,061

DEVICES FOR FACILIT'ATING BREATHING AND PRODUCING ARTIFICIAL RESPIRATION Filed May 27, 1955 2 Sheets-Sheet 2 FIG? FIGB nvVENToR. y Monroe Harry Goodner ATTORNEYS United States Patent- DEVICES FOR FACILITATING BREATHING AND PRODUCING ARTIFICIAL RESPIRTION Application May 2,7, 1955, Serial No. 511,501

19 Claims. (Cl. 128 29) This invention relates to devices for administering gas, such as oxygen, air or other gases, or a mixture of gases to facilitate breathing or for other purposes.

Such devices are attached directly or indirectly to a face mask which tits over the patients mouth and nose or to a tracheal tube.

When the device operates to supply a relatively constant ilow of oxygen, air or other gases to a patient who is capable of natural breathing, it is referred to as an inhalator. Where the device is used for aiding human beings or animals in instances where breathing is hindered or requires artificial aid or stimulation by the application alternatively of positive and negative pressures, as, for example, in cases of asphyxiation caused by drowning, poisonous gas, poliomyelitis, heart attack, or the like, it is referred to as a resuscitator.

It has been found that there is great need for a device which is sufliciently flexible in operation that it can be shifted substantially instantaneously from applying one set of alternating gas pressures to another substantially different set of gas pressures, as, for example, from ap.- proximately 14 mm. positive pressure and 11 mm. negative pressure to approximately 27 mm. positive pressure and zero negative pressure. In some cases, as, for example, When a patients air passages have been inamed and swollen by poisonous gases it is necessary, in order to maintain breathing, to apply intermittently positive pressure great enough to force open the patients airpassages and admit air to the patients lungs. In such cases exhalation may be accomplished by the patients lungs without applying negative pressure, it being desirable, however, during the exhalation period to reduce or eliminate positive pressure. In cases Where it is discovered that a patients air passages have become closed, or partly closed, it may be necessary to shift immediately from low alternate positive and negative pressures ordinarily used in artificial respiration, or from supplying a continuous ow 4of oxygen, air, or other gases as when the device is employed as inhalator, to supplying a higher positive pressure intermittently with periods in between for exhalation. Such greater positive pressure applications would of course be used only in extreme cases, but where it is discovered that the patients condition demands such treatment it must be possible to supply it substantially instantaneously.

An object of the invention is to provide improved apparatus of the above described kind.

Another object is to provide a device capableV of shifting efliciently and instantaneously from applying one set of gas pressures to another substantially different set o f gas pressures, as for example, from approximately 14 mm. positive pressure and 11 mm. negative pressure to ap,- proximately 27 mm. positive pressure and zero negative pressure.

Another object of the invention is to provide a cornpact portable device which is highlyI flexible in operation and capable. f beine employed in the several'r ways and for the several different purposes indicated above.

2,845,061 Patented July 29, 1958 'ice Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the appended claims.

In the accompanying drawings in which are shown by way of illustration several possible embodiments of my invention:

Figure 1 is a plan view of a horizontal section taken in line 1 1 of Figure 2;

Figure 2 is a side elevation of a vertical section taken in the line 2 2 of Figure l;

Figure 3 is a fragmentary side elevational view;

Figure 4 is a top plan view of the member 14.

Figure 5 is a bottom plan view of member 14;

Figure 6 is a side elevational view taken on the line 6 6 of Figure 4;

Figure 7 is an end view of the valve closure element shown in Figures 1 and 2;

Figure 8 is a face view of a washer comprising part of the valve assembly, and

Figure 9 is a side view of the means shown in Figure l for adjusting the negative pressure bias.

While features of the present invention have more general application, the invention has its preferred embodiment in a relatively small, compact, portable device, which is preferably arranged for direct connection to a gas administering mask arranged for positioning over a patients face, or nose and mouth, to administer oxygen, air, or other gas for inducing or promoting respiration, aiding breathing or other purposes. It is obvious, however, that many variations of construction canbe made without departing from the invention, such as changes in shape and construction of the parts, the inclusion of a lleXible hose or other coupling between the device and the mask, and the elimination of the means to convert the device into an inhalator, where such arrangement is not required.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the drawings, the resuscitator and inhalator shown therein comprises, in general, a substantially cylindrical sheet metal casing formed of a short section of sheet metal tubing 1l) and the generally rounded or

domeshaped ends

12 and 13. The end 13 has a central opening through which is inserted the tubular section 14a of the member 14 which fits within end 13 but is flatter than end 13 providing an air chamber 14h between them after they are assembled. Tubular section 14a is fitted into a tubular ferrule 15 comprising part of gas administering mask 16. Gas is supplied to' the device through a gas inlet coupling assembly 11 to which is coupled a glas supply hose 18 connected to a source of regulated gas supply. The device can be of a relatively small size, for* example, a resuscitator and inhalator constructed as, shown in the drawings has been made having a diameter of only 2% inches, and weighing approximately thirteen Quncesl,

Tubular portion 11)'v of the casing comprises a short pic of thin-walled `tubing, externally threaded at each end. While. the device may be used in any position encl` wall 12 will be described, for convenience, as the top of the device. End wall 152 comprises a dome-shaped pressed Sheet metal Gap` having a Cylindrical imite/,friaHit-tht@adedY flange 19 at its outer edge adapted to screwl onto .the unrestv end oftubuler'section 10.. A. round centralnening isproyided in top wall 12, the portion, Zlofthe:

wall bordering on the opening being curved inward to provide a smoothly contoured recess.

Bottom end wall 13 carries a ange 22 at its outer edge formed similarly to flange 19 to screw onto the lower end of tubular casing wall 10. The opening at the center of dome-shaped bottom wall 13 is of a relatively large diameter and projecting axially outward through it is the tubular section 14a of the member 14. Member 14 fits within member 13, leaving the air space 14b between them, and has inlet and outlet safety valves therein. Surrounding said central opening in end 13 are a plurality of apertures 13a to supply air into the space 14b. Tubular section 14a is adapted for insertion into the ferrule 15 attached to the mask 16 which may be of conventional form and construction.

A pair of diaphragms comprising an upper diaphragm 27 and a lower diaphragm 28 are clamped in horizontal position within the casing, dividing it horizontally into three chambers, namely an upper chamber 29, a middle chamber 30 and a lower chamber 31.

Diaphragms

27 and 28 may be formed of any suitable flexible impervious material such as impregnated cloth, or thin corrugated metal. They are clamped on at their outer circular edges between the inwardly extending upper and lower anges a and 10b of tubular casting 10, on the ring 27a, and the upwardly extending ilange 14e` of member 14, respectively.

A valve housing 36 is floatingly carried by

diaphragm

27 and 28, the valve housing being suspended between the centers of the diaphragms. The housing is centered within the casing and prevented from turning, and thereby twisting the diaphragms, by the

arms

23 and 24, pivotally connected to said housing by

pivots

23a and 24a, respectively, and to the gas inlet coupling assembly by

pivots

23b and 24b, respectively. Housing 36 comprises a metal casting provided with suitable gas passages and a valve chamber, which a's shown is a cylinder 37 in which a slidable valve closure element 38 is carried. The valve housing 36 also carries a venturi 39 and the

valve assembly

37, 38 serves to direct gas through suitable passages in the housing 36 to the venturi for purposes of supplying positive and negative gas pressures to the patient, as will be more fully described.

Diaphragm

27 and 28 each have central apertures and are each clamped in their central areas by a pair of clamping washers or discs. For example, diaphragm 27 is clamped between circular metal washers 40 and 41 which are held against the two faces of the diaphragm and which have central openings registering with the centrol opening in the diaphragm. Diaphragm 28 is similarly clamped between

washers

42 and 43. The upper end of iloah'ng valve housing 36 has an external threaded portion 45 which extends through the central aperture provided in diaphragm 27 and clamp washers 40 and 41,

and a hollow internally threaded nut 46 is screwed onto 45 thereby clamping the upper end of housing 36 in the central opening in the diaphragm. A screw 46a provided with a screw-driver slot 47 is used to close the bore in nut 46 through which access may be had to the jet 71 to clean it and venturi 39. The lower end of housing 36 carries threaded axial projection 48 which extends downward through the central aperture provided in diaphragm 28 and is clampedthereto by clamp nut 49 which is tightened against lower clamp washer 42. An internally threaded lower cap 65 is screwed onto projection 48. Cap 65 has an integral circular flange 65a which extends to within a short distance of the inside wall of tubular portion 14a of member 14 and is provided with perforations 65b so that the flange protects the inside of the casing from the entrance of foreign particles and still permits free gas passage through and around the flange. A screw-driver slot 65e on cap 65 permits ready removal for cleaning jet 72 and Venturi 39.

Housing 36 is connected by a section of flexible rubber or plastic tubing 50 (Figure 1) to gas coupling assembly 11 in order to convey gas from the supply source to the floating valve housing. In addition, a valve control arm 51 comprising a straight piece of spring metal rod is rigidly supported in the casting of gas coupling assembly 11 and extends axially through gas supply tube 50 and the gas passage 52 of gas inlet nipple 53 which comprises part of valve housing 36, into cylinder 37 where the end of valve control arm 51 is received in central transverse passage 54 in valve closure element 38, so that element 38 is supported by spring arm 51 (see Fig. 7).

Valve cylinder 37 has its axis parallel to the axis of the device and hence parallel to the direction of motion of oating valve housing 36 as

diaphragms

27 and 28 are exed. Gas inlet passage 52 enters cylinder 37 in the mid-portion of its cylindrical side wall. The bottom wall of cylinder 37 is provided with an annular ridge 55 surrounding gas passage section 56a which together with sections 56b and 56e makes up a gas passage leading from the valve to chamber 57 inside cap 46. A plate 58 carrying an annular ridge 59 similar to ridge 55 is screwed into the internally-threaded upper end of valve cylinder 37 and seats against a shoulder at the lower end of the threaded section to provided a second valve seat. Plate 58 has a central opening 60 leading into a small chamber 61 above the plate which is closed by a screw cap 62 threaded into the top of the cylinder. A gas passage 63 made up of sections 63a and 6311 drilled through the casting forming housing 36 extends down to lower end 48 of the casting communicating with a small chamber 64 inside lower cap 65 which is threaded onto the externallythreaded lower end 48 of the casting, as clearly seen in Figure 2.

Valve closure element 38 comprises a sliding metal block of generally rectangular shape having annular ridges 66 and 67 on its upper and lower faces opposing ridges 59 and 55, respectively, at the ends of the cylinder. The diameter of ridges 59 and 66 is made larger than the diameter of

ridges

55 and 67 to require greater force to unseat member 38 from 59 than from 55 to cause the device to provide greater positive gas pressure for inhalation than negative gas pressure for exhalation. As seen most clearly in Figure 7 the four corners of block 38 are rounded off to provide cylindrical bearing portions which can slide on the inside cylindrical wall of cylinder 37 while still permitting gas to freely pass around the element 38 from gas inlet passage 52. Element 38 is drilled with a central transverse passage 54 which is of reduced diameter at its mid-portion to form a loose socket into which the end of valve control arm 51 extends as seen in Figure 7.

Interposed between element 38 and stationary valve seat ridges 59 and 55 are a pair of flexible washers 69 and 70 having a generally rectangular shape with the corners cut oil. to provide cylindrical bearing surfaces engaging the inside wall of cylinder 37 as shown in Figure 8. It'will be evident that valve closure element 38 is suspended on control arm 51 in a relatively stationary position so that as floating valve housing 36 moves up and down in response to motion of

diaphragms

27 and 28 element 38 will be shifted into contact with one or the other of washers 69 and 70, these washers in turn being held against ridges 59 and 55 to cut oli the gas ow through one or the other of passages 63 and 56. Valve control arm 51 is suticiently resilient, however, to permit it to yield slightly so that, as long as the gas pressure in cylinder 37 exceeds that in the passage which is closed by element 38 by an amount sucient to overcome the restoring force of spring arm 51, the valve will remain closed. However, when the movement of housing 36 has been suicient to build up a restoring force equal to the gas pressure the valve will suddenly be snapped from one end of the cylinder to the other, thereby to open one passage and close the other.

Casting 36 comprising the valve housing is drilled along one side to provide a venturi passage 39 having one end tion of the ring to a few degrees in either direction.

opening into the middle chamber 30 between

diaphragms

27 and 28, and the other end opening into gas administering chamber 31 beneath diaphragm 28. Holes are also drilled in casting 36 from both the upper and lower ends in alignment with the venturi passage and a pair of

tubes

71 and 72 are affixed in these holes to provide jet passages of the required diameter extending from

chambers

57 and 64, respectively. The material of casting 36 is cut away in a smoothly rounded manner at the ends of venturi 39 to deflect gases issuing from the venturi while still permitting either of

jet tubes

71 and 72 to project a jet of gas into the venturi on the opposite cycle.

Upper chamber 29 is open to the atmosphere by virtue of the space between central opening 20 and cap 46 and the presence of additional vent holes 74 in end Wall member 12. Lower chamber 31l is normally closed and in communication only with the face mask 16 but is provided with safety inlet and

outlet valves

25 and 26, respectively, which when unseated communicate through dish-shaped member 14 with the space 14b between it and casing end member 13. Member 14 has therein two circular openings 25a and 26a.- Opening 25a is ordinarily closed by the circular valve member 25b which seats on the inner surface of member 14 and is supported at one end of spring arm 25C, the other end of which is fixed to the inner face of member 14. When the pressure within the operating chamber defined by diaphragm 28 and member 14 is reduced beyond a predetermined amount, valve 25 will open to admit air into the operating chamber to be supplied to the patient. Opening 26a is ordinarily closed by the circular valve member 26b which seats on the outer surface of member 14 and is supported on one end of spring arm 26e, the other end of which is fixed to the outer surface of said member 14. Ordinarily valve member 26 will remain closed, but it will open when the pressure within said chamber becomes greater than a predetermined amount to exhaust gases from said chamber and thereby reduce the pressure therein and in said face mask. (See Figures 2 and 4.)

Because of the air space between member 14 and end wall 13, both said intake and exhaust valves are protected from contact with external objects and from being inadvertently closed or held down, as, for example, by the thumb or fingers of a person holding the device. The vents 13o in member 13 provide a supply of air into space 14b at all times for it is impossible for all of these openings to be simultaneously closed inadvertently by the position of the thumb or fingers of the person holding the device.

An adjustable gas vent is provided in wall of middle chamber 30 comprising a slot 75 cut part way around wall 10, and a threaded ring 76 which is threaded onto the upper threaded portion of cylindrical wall 10 below flange 19 of the top wall. slot 77 corresponding to slot 75 in the casing wall and the outer surface of the ring is knurled to permit the ring to be turned manually to bring slot 77 into register with slot 75 to a greater or lesser extent. A short pin 78 extends in from ring 76 through slot 75 to limit the rota- When ring 76 is turned to one extreme, slot 75 will be closed by the ring while at the other extreme a passage for the entrance and exit of air or other gases is provided by the aligned

slots

75 and 77.

A one-way valve 79 is also provided in the wall of chamber 30 and comprises a hollow screw 80 having a gas passage 81 extending through its stem, and the cross passage 82 to prevent the valve failing if disc 84 becomes lodged across the inner end of screw 80. Screw 80' passes inward through wall 10 into a small valve chamber 83 containing a rectangular valve disc 84 of mica or other light sheet material which seats against an annular ridge S5 surrounding an opening leading from the valve chamber into chamber 30. When the gas pressure outside chamber 30 exceeds the pressure inside, disc 84 will be Ring 76 is provided with aV pressed against ridge 85 to close the valve and prevent However, when the to ex the diaphragm 28 and therefore the pressures which will be exerted in the operating chamber 31 and from there communicated to the patient through the tubular section 14a of member 14 and face mask 16. As

shown herein, the friction member 87 is a curved leaf spring which is pivotal-ly mounted at one end on screw` 24b projecting from the casing wall, specically cou-y pling 11 and at the other end on screw'24a which projects from the boss 36a on housing 36. Arm 24 is also mounted on said screws and acts as a retainer to hold member 87 against the coupling 11 and housing 36. Extending through arm 24 into contact with member 87 is the adjustingscrew 88 by which the extent of frictional contact of member 87 on housing 36 may be controlled.

Also extending from the casing wall is a spring mem- I ber 89 which is substantially U-shaped and comprises upper and lower arms 89o and 89b which press on the housing 36 in opposite directions. As shown, the ends of said spring member are secured to, and .movable with, the ring 90 which is rotatable around chamber 83, i. e. around an axis which is at right angles to the axis of the housing 36, to increase the biasing force exerted on the housing in one direction and to correspondingly decrease the `biasing force exerted on the housing in the opposite direction. This second spring 89 is thus a second frictional member which is employed in combination with said first spring member 87 to regulate the positive and negative gas pressures relative to one another. By this means adjustment of the positive pressure applied to the operating chamber and face mask can be readily varied a few degrees from a given positive pressure such as, for example, 14 mm. and the negative pressure can be varied from a given negative pressure, such as, for example,-

For shifting instantaneously between two sets of gas pressures having a greater differential, for example,f27 mm. positive pressure and zero negative pressure, a third and larger leaf spring 91 is provided, together with toggle switch means 94 for moving said spring from opera-r tive `to inoperative position. Said spring 91 may be either integral with or secur-ed to a bearing block 93 which is pivotally mounted on a tubular spacing member 93a supported by said screw 24bbet'ween its head and said arm 24, for movement toward and away from the housing 36 around screw 24h. It is normally positioned to press on the housing 36 as, for example, by contact with the arm 24, to bias the housing to greatly increase the amount of gas pressure necessary to move the diaphragm 28 in the direction which controls the supply of positive pressure to the operating chamber and the face mask. By suitable adjustment of screw 241; the additional bias provided by member 91 for increasing the positive gas pressure may be made just sufficient to oiset atmospheric pressure in the locality where the device is used and thereby cause the negative pressure developed during alternate movements of the diaphragm 28 and housing to be substantially Zero.

. The toggle switch 94 comprises the thumb piece 94a which is external to the casing, the intermediate narrow shank portion 94h comprising a ball which seats within a socket within the casing wall, and the bifurcated portion 94e extending into the casing. Between the arms of portion 94C is a pin 95 which serves as a stop against which rides the spring 96 which is secured to the casing 10 at 96a and gives the toggle a snap action as pin 95 passes the high point of its curved path'wherethumb piece 94 is raised or lowered. Inwardly projecting portion 94C extends under the free end of said spring member 91 and when in one position leaves the spring 91 free to press upon the housing 36, through arm 24, and when in its other position engages and lifts it out of contact with the housing. Thus, when the toggle switch 94 is in one position the device will operate at the set of pressures ordinarily employed for resuscitation, such as, for ex ample, 14 mm. positive pressure and 1l mm. negative pressure, and when the toggle switch is moved to its other position the device will immediately operate on a substantially different set of pressures, such as for example, approximately 27 mmypositive pressure and zero negative pressure. Pressure in the order of 27 mm. positive and to 3 or 4 mm. negative are desired in such cases Where the patients air passages have become substantially closed, due to swelling or presence of mucus or foreign matter, and it is necessary, at least momentarily, to supply gas under pressure much greater than the usual pressure employed in resuscitation in order to open the air passages and get oxygen into the patients lungs.

Since no novelty is claimed herein for the gas coupling assembly, only a brief description of it is given. It comprises a metal casting 97 mounted against the inside of cylindrical wall in middle chamber 30 and having a threaded nipple 98 extending out through an accommodating opening in wall 10. The casting is clamped in the opening by a nut 99 threaded onto nipple 98 and bearing against a washer 100 shaped to conform to the outer surface of wall 11. A cylindrical passage 101 extends through nipple 98 and terminates in a closed recess. Casting 97 has a side arm 102 carrying a branch passage 103 communicating with cylindrical passage 101, and the end of side arm 102 carries a nipple 104 directed toward nipple 53 on floating valve housing 36. Flexible tube 50 is fitted over

nipples

53 and 104 thereby providing a continuous gas passage to valve chamber 37 from the outside of the device through gas coupling assembly 17 and tube 50. Valve control arm 51 extends through the gas passage of nipple 104 to the intersection with gas passage 103 and is supported at its fixed end 10S in a hole drilled through the wall of arm 102 by a press-tit or by brazing, thereby affording a rigid support for the xed end of arm 51.

It will thus be seen that there has been provided by this invention a method and apparatus in which `the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

What I claim is:

l. A resuscitator comprising a casing, a pair of spaced flexible diaphragms dividing the interior of said casing into three chambers, a floating valve housing suspended by said diaphragms, means for centering the valve housing within the casing and preventing it from being displaced angularly, a valve chamber within said housing, the axis of said valve chamber being parallel to the axis of said diaphragms, a gas inlet coupling extending into said casing between said diaphragms, and a flexible gas conduit within said casing connecting said inlet coupling to said valve chamber, said oating housing carrying a pair of gas passages communicating with the respective ends of said valve chamber, a valve closure element slideable in said valve chamber, and a supporting arm therefor xed at its outer end and extending from the casing wall into said valve chamber substantially normal to the valve chamber whereby axial movement of said oating valve housing will shift said valve closure element between the ends of said valve chamber, alternatively to close said respective gas passages, said valve housing including a venturi passage extending between the middle one of said three charnbers and a second of said chambers, and a lirst venturi jet fed by one of said gas passages which is closed by movement of said valve housing in a direction away from said second chamber, and a second venturi jet fed by the other of said gas passages, said first venturi jet being directed into said venturi passage to drive gas from said middle chamber and said second jet being directed into said venturi passage to drive gas from said second chamber into said middle chamber, a gas administering conduit extending from said second chamber, said casing having an atmospheric opening into the third of said chambers, and a gas escape valve leading out of said middle chamber.

2. The device claimed in claim 1, including means for regulating the total gas pressure, both positive and negative, applied to said gas administering conduit during a cycle of operation.

3. The device claimed in claim l, including means for regulating the gas pressure within said gas administering conduit while gas is being supplied into said conduit, and compensating means for regulating the gas pressure within said conduit while gas is being exhausted from said conduit in relation to the said pressure while gas is being supplied into the conduit.

4. The device claimed in claim 1, including means for regulating the gas pressure within said gas administering conduit while gas is being supplied into said conduit, in relation to the total positive and negative gas pressure applied during an inhalation-exhalation cycle.

5. The device claimed in claim 1, including means for regulating the gas pressure applied to promote exhalation to the total positive and negative gas pressures applied during an exhalation-inhalation cycle.

6. The device claimed in claim l, including means for regulating the total positive plus negative pressures applied during an operating cycle and means for regulating the negative pressure applied during part of the cycle relative to the total negative plus positive pressures employed during a full cycle.

7. The device claimed in claim 1, including means for shifting instantaneously from one set of positive-negative pressures to another.

8. The device claimed in claim 1, including means for loading said housing member, and means for adjusting said member to control the force it exerts on said housing.

9. The device claimed in claim 1, including means for acting on said housing to bias it and change its resistance to movement and thereby vary the pressures required to move it and consequently the positive and negative pressures applied to said gas administering conduit, and means for substantially instantaneously activating and de-activating said biasing means to shift from one of said sets of pressures to another.

10. The device claimed in claim 1, including means for biasing the housing and means for connecting said biasing means to the housing, and disconnecting it from the housing, to change the gas pressures employed from a positive pressure of substantially 12-16 mm. of mercury and a negative pressure of substantially 9-13 mm. of mercury, to a positive pressure of substantially 25-29 mrn. of mercury and a negative pressure of substantially zero.

11. The device claimed in claim l, in which said casing comprises an annular end member and in which said second chamber comprises one of said diaphragms and a member which tits within said end member and has a tubular portion which extends through the opening in the end member, said member being spaced from said end member providing aspace between them, and said end member being provided with a number of vents communicating between said space and the surrounding atmosphere, and valve means in the wall of said member, com- 9 municating between said second chamber and said space.

12. The device claimed in claim 1, in which communication, between said :lrst jet and the said gas passage which is closed by movement of said valve housing in a direction away from said second chamber, is provided by an axially bored nut fitting over the proximate-ends of said jet passage and said gas passage, with its bore aligned With said jet passage, and a screw for closing said bore.

13. The device claimed in claim 2 in which the means for regulating the total gas pressure applied during a cycle comprises a friction member .supported from the casing and bearing on said valve housing, and means for increasing and decreasing the force exerted on the housing by said member.

14. The device claimed in claim 3 in which the means for regulating the gas pressure exerted in said administering conduit during exhalation comprises means supported from the casing and extending into contact with the valve housing and adjustable toward and away from the housing.

15. The device claimed in claim 14 in which said pressure regulating means is mounted in movable support means on the inside of said casing and a slot is provided in the casing wall through which means may be inserted for moving said support means to thereby vary the force exerted by said pressure regulating means on said valve housing.

16. A resuscitator device comprising an inlet conduit adapted to be connected to a source of gas supply, venturi means including rst and second jets for creating positive and negative gas pressures respectively, a distributing valve housing having a valve chamber fed by said inlet conduit and having first and second jet supply passages leading to said first and second jets, respectively, and a valve element movable between two positions in said valve chamber for alternatively closing said jet passages, the gas pressure in said valve chamber resisting the opening of the closed valve passage in both positions of said valve element, a gas chamber supplied with positive and negative gas pressures by said venturi means, `one of the walls of said chamber being movable, said valve housing being coupled thereto for control thereby, and a resilient support arm for said valve element mounted independently of said valve housing, to shift said valve element from the rst to the second of said positions responsive to negative gas pressure in said gas chamber and from the second to the first of said positions responsive to positive gas pressure in said gas chamber, means for varying the positive pressure and the negative pressure required to move said valve element, and means for changing the ratio between the required positive pressure and th required negative pressure.

17. A resuscitator comprising, in combination, a hollow casing having a gas administering chamber therein,

10 a exible diaphragm in said casing comprising a wall of said chamber, a valve housing carried by said diaphragm and having a valve chamber therein, a exible gas supply conduit leading into said valve chamber, a gas injector jet directed into said gas administering chamber and a gas ejector jet directed out of said chamber, said valve housing having iirst and second gas passages leading from said valve chamber to said jets, respectively, and a shiftable valve closure element in said valve chamber movable with respect to said valve chamber between a rst position for closing said first passage and a second position for closing said second passage, a support for said valve closure element mounted in said casing independently of said diaphragm, whereby movement of said valve housing by said diaphragm will shift said closure element, means acting when in contact with said housing to bias said housing and thereby increase the pressure required to move said diaphragm in either direction, and toggle switch means for moving said biasing means between active and inactive position.

18. A resuscitator comprising, in combination, a rst gas chamber, a second gas chamber having a gas administering conduit leading therefrom, a venturi extending from said first to said second gas chamber, a first jet in said first chamber for projecting a gas into said venturi, a second jet in said second chamber for projecting a gas into said venturi, a valve for supplying a gas` alternatively to said first and second jets, said first chamber having a gas inlet and outlet passage communicating with the atmosphere and an adjustable valve for regulating the rate `of gas flow through said passage, thereby to control the rate of gas ow through said venturi, and means for regulating the resistance of said diaphragm to movement and the positive and negative pressures required to move it.

19. A gas administering device for administering a mixture of gases, comprising, in combination, a first gas chamber, a second gas chamber having a gas administering conduit leading therefrom, a diaphragm separating said chambers, a venturi extending from said first to said second gas chamber, a jet in said first chamber for projecting a first gas into said venturi, said first chamber having a gas inlet passage for admitting a second gas thereto, and an adjustable valve for regulating the rate `of gas admission through said inlet, thereby to regulate both the rate of gas ow and the composition of the gas mixture passing through the venturi, and means for regulating the resistance of said diaphragm to movement to provide a choice between a plurality of sets of pressures within said gas administering conduit.

References Cited in the iile of this patent UNITED STATES PATENTS Goodner Oct. 4, 1949