US3028859A

US3028859A - Underwater breathing device

Info

Publication number: US3028859A
Authority: US
Inventors: Wallace F Mitchell
Original assignee: Dacor Corp
Current assignee: Dacor Corp
Priority date: 1955-09-15
Filing date: 1955-09-15
Publication date: 1962-04-10
Anticipated expiration: 1979-04-10

Description

April 10, 1962 .w F. MITCHELL 3,028,859

UNDERWATER BREATHING DEVICE Filed Sept. 19, 1955 3 sheets-sheet 1 QJ IV '2' INVENToR.

, lQQNALLAm-I F. MITCHELL nJ/eha' Cri/M ATTORNEYS April 10, 19.62 w. F. MITCHELL 3,028,859

UNDERWATER BREATHING DEVICE Filed Sept. 19, 1955 5 Sheets-Sheet 2 ATTORNEYS April 10, 1952 W. F. MITCHELL 3,028,859

UNDERWATEE BREATHING DEVICE Filed Sept. 19, 1955 3 Sheets-Sheet 3 FIG. 6

INVENTOR.

3o WALLACE F. MITCHELL ATTORNEYS Unite States Patent 3,028,859 UNDERWATER BREATHING DEVICE Wallace F. Mitchell, Arlington Heights, Ill., assigner to Dacor Corporation, a corporation of Illinois Filed Sept. 19, 1955, Ser. No. 535,067 9 Claims. (Cl. 12S-142) This invention relates to underwater breathing devices and has to do more particularly with an underwater breathing device of the self-contained type.

Self-contained underwater breathing devices as heretofore constructed have usually included a tank of compressed air, an air intake hose line leading from the tank to a mouthpiece adapted to be held in the mouth of the user and an exhaust air hose line leading from the mouthpiece to a one-way discharge or exhaust valve. Connected to the intake line is a pressure regulator adapted to reduce the pressure of the compressed air to that of the surrounding water and to avoid the loss of air. In such devices the pressure regulator includes a regulator chamber defined in part by a flexible diaphragm which is exposed at one face to the water and consequently is subjected to the pressure of the water, the diaphragm being arranged to cause the opening of a demand valve in the regulator leading to the intake hoseline Whenever the pressure in the intake line is a predetermined amount less than the water pressure, such as when the user inhales. It was found that such devices were subject to loss of air through the exhaust valve due to the spontaneous opening of the latter whenever the pressure exerted by the water on the diaphragm exceeded that exerted by the water on the exhaust valve by an amount equal to that suiicient to cause the diaphragm to open the demand valve. In order to prevent such spontaneous escape of air it has been proposed to locate the exhaust valve at a distance from the center pressure of the diaphragm less than the height of a column of water representing the pressure necessary for operation of the demand valve. This not only places serious and undesirable limitations on the design of the device but also places a limitation on the pressure necessary to operate the demand valve.

Another prior art proposal has been to locate the exhaust Valve in a chamber having a restricted outlet opening whereby when the exhaust valve is in a position above the level of the diaphragm, the chamber opening is downwardly and lower than the diaphragm, and air therefore is trapped in the chamber to prevent water Vfrom acting directly on the exhaust valve, with the result that the pressure on the exhaust valve is equal to that of the water at the chamber opening which is greater than the water pressure on the diaphragm. This proposal also imposes serious limitations on the design of the device.

The prior art devices also are subject to other disadvantages. The use of a single valve-operating diaphragm renders the device vulnerable upon rupture or leakage of the diaphragm, upon which occurrence the demand valve can no longer be operated by the user inhaling and the air supply therefore is eifectively cut off. Also, the single diaphragm is exposed to the water on one face and consequently is subjected to the inertia of the water and thus the breathing action is made more difficult and less uniform than would be the case if the diaphragm were operated with air on both faces.

An object of my invention is to provide a new and improved, self-contained, underwater breathing device.

Another object is to provide a self-contained underwater breathing device which is not susceptible to spontaneous loss of air therefrom regardless of the position of the device in the water. I

A further object is to provide a self-contained underwater breathing device wherein the exhaust valve may be disposed in any location relatively to the diaphragm ICC which controls the operation of the lair-demand valve without causing spontaneous loss of air therethrough.

A further object of my invention is to provide a selfcontained under water breathing device wherein the diaphragin which operates the air-demand valve is not exposed to the water surrounding the device and therefore is not subjected to any inertia except that due to its own mass and that of the air in the device.

Another object is to provide a self-contained underwater breathing device wherein the valve-operating diaphragm is fully enclosed and protected and the danger of rupture of the diaphragm is minimized.

Another object is to provide a self-contained underwater breathing device having two diaphragms one of which encloses the other diaphragm-whereby upon rupture of either diaphragm the device is operative and therefore is not subject to failure by reason of the rupture of either one of the diaphragms.

Another object is to provide a self-contained underwater breathing device wherein the valve-operating di aphragm is instantly responsive to pressure differences in the lungs of the user.

Another object is to provide a self-contained underwater breathing apparatus wherein the air pressures within the device are instantly and constantly equalized.

Another object is to provide'a self-contained under- Water breathing apparatus whcrein'a large diameter, highly sensitive, valve-operating diaphragm is employed which insures instant and accurate equalization of air pressures in the device.

Other objects and advantages of the invention will appear from the following description taken in connection with the appended drawings wherein:

FIGURE l is a fragmentary front elevational view of the device showing particularly the pressure regulator and portions of the air lines and air tank;

FIG. 2 is an enlarged fragmentary sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a somewhat diagrammatic showing of the device with parts broken away and in section to show the interior construction, the device being. shown in the condition it assumes during the inhale cycle;

FIG. 4 is a view similar to FIG. 3 only showing the device in the condition it assumes during the exhale cycle;

FIG. 5 is a view of a section taken along line 5'5v of FIG. 4;

FIG. 6 is a View of a section taken along line 6-6 of FIG. 2;

FIG. 7 is a view of a section taken along line 7--7 of FIG. 2;

FIG. 8 is a view of a section taken along line 8 8 of FIG. 2; and

FIG. 9 is a View of a section taken along line 9 9 of FIG. 2.

The device in accordance with my invention includes a tank or ilask 10 for containing compressed air, a regulator 11 connected to the flask 10 by a clamp 12 for regulating the Withdrawal of air from the flask 10, an air hose 13 connected to the regulator, and a mouthpiece 14 connected to the air hose 13 for inhaling air from the ilask through one part of the air hose and for exhaling air from the lungs through another part of the air hose. The clamp 12, the regulator 11, the air hose 13 `and the mouthpiece together constitute an assembly which may :be detached from the flask 10 as a unit in order to permit replacement of the flask, which assembly `I designate as 'a breathing unit.

The flask 10 may be of any suitable conventional construction and is of sufficient strength to contain air at the customary pressure of approximately .2,000 pounds per'square inch. It is provided with the usual neck 1`5 having an outlet passage 16 therein leading from the interior of the tank. The clamp 12 is suitably formed to clamp the regulator 11 to the neck 15, a clamp screw (no't shown), having a suitable handle, being provided for tightening the clamp to draw Vthe regulator intoV sealing engagement with the neck and to hold the regulator on the neck until the clamp is released. The tank is provided with the usual manually operated shut-off valve (not shown) for closing the tank to prevent loss of air when the device is not in use and especially where the tank is disconnected from the regulator.

The regulator 11 includes a body 26 having a recess therein providing a primary reduction chamber 21. A primary valve housing 22 is threaded into a bore 23 in the body 20 leading to the primary reduction chamber 21. The primary valve housing 22 has a passage extending therethrough which provides communication between the outlet passage 16 of the tank and the primary reduction chamber 21. The primary valve housing 22 is formed with a tlange 24 for the purpose of engaging the clamp 12 and retaining the pressure regulator on the neck 15, which ange is preferably of hexagonal shape in order to facilitate screwing the primary valve housing into the body 2t).

The passage in the primary valve housing 22 is formed l with a circular bore portion 30 and orifice 31 and a second circular borev portion 32, all of which are in alignment. Thus the

bore portions

30 and 32 and the orifice 31 provide a continuous passage for air from the outlet passage 16 to the primary reduction chamber 21.

Formed around the orifice 31 is a valve seat 35 of annular form and having a reduced outer face or edge portion providing an annular valve seat of relatively narrow width.

A primary valve 36 is slidably disposed in the bore 30 for movement between closed position abutting the valve seat 35 and an open position spaced from the valve seat. The primary valve 36 includes a body 37 of generally square cross-sectional shape as seen particularly in FIG. 9 of the drawings and therefore a plurality of passages 38 are provided between the valve body 37 and the bore to permit air to pass around the valve member.

The valve member 37 is provided with a recess 40 in which is disposed a valve insert formed of flexible resilient sealing material. The material from which the insert 41 is formed is one which retains its resiliency and sealing properties over long periods of use and is not subject to deterioration. Preferably, I form the insert from a suitable plastic, and for this purpose I have found that a polytetratluoroethylene plastic marketed by E. I. du Pont de Nemours and Co., of Wilmington, Delaware, under the trade name Teon has provided excellent results.

The recess 40 is disposed axially of the primary valve member 37 and the insert 41 is symmetrically disposed in the recess. Disposed axially within the recess and within the insert 40 is an anvil element 42 formed of metal which is secured in the material of the valve member 37 below the bottom of the recess 49 so as to be held irmly and securely therein. The corresponding faces of the valve member 37, the insert 41 and the anvil 42 are very carefully machined so that they all lie in the same plane and particularly the end faces of the insert 41 and the anvil 42. Preferably I form the assembly constituting the valve 36 by disposing the insert and anvil in the recess 41 and staking the end face of the valve member 37 to crimp the edge around the insert, whereafter the end faces of all three members are machined olf so that they are ilush.

The valve 36 is urged into closed position against the valve seat by a spring 45. seated in a recess 46 in the valve member 37 and bearing at its outer end against a retainer 47 rigidly secured in the valve housing 22 over the end of the bore 30. The seat member 47 is formed with an opening therein to permit the passage of air therethrough, and a screen 48 is secured across the bore 30 by the member 47 for preventing the passage ofany solid particles into the bore 30.

The outer side of the primary reduction chamber 21 is closed by a diaphragm 50 extending across the face of the body 20 and clamped thereto by an intake housing 51 secured in place by a plurality of screws 52 extending through the end wall of the housing 51 and threaded into the body 2). The diaphragm 50 is formed from a suitable, tiexible, resilient, waterproof material, such as rubber. Carried centrally of the diaphragm Si) is a pusher member 55 having a stem 56 extending through an opening 57 in the diaphragm 50 and secured to the diaphragm by a nut 58. The nut 58 bears against a bearing washer 59a which serves to clamp the central portion of the diaphragm 56 between itself and the head of the push member 55. The push member has a head 59 on the inner side of the diaphragm adapted to bear against the head 60 of a push rod 61 having a stem 62 positioned to en gage the exposed end of the anvil 42 for moving the primary valve 36 away from its seat.

The head 60 of the push rod 61 is formed of generally square cross-section and whereby there is provided passages 63 around the head 6() from the inner portion of the bore 32 to the primary reduction chamber 21.

The push member 55 is normally urged inwardly to cause the push rod 61 to move the valve 36 olf its seat by a spring 65 bearing at one end against the push member 55 and at the other end against a spring retainer 66 having a flange portion 67a: bearing against the inner face of the intake housing and secured to the body 20 by the screws 52 and a cup portion 67 for retaining and seating the spring 65.

The primary valve serves to permit the ow of air from the flask 10 to maintain a predetermined air pres sure within the primary reduction chamber 21. Preferably the pressure of the air maintained within the primary reduction chamber 21 is about 50 to l0() pounds per square inch. Whenever the pressure of the air within the primary reduction chamber 21 falls below the desired value, the spring 65 urges the pressure member 55 inwardly, which in turn urges the push rod inwardly and thereby moves the primary valve 36 away from its seat to let air pass through the outlet passage 16, the screen 48, the passages 38, the valve orifice 31, the bore 32 and the passages 63 and into the primary reduction chamber 21. When the desired pressure within the chamber 21 is reestablished, the diaphragm 5t) is moved outwardly against the force of the spring 65 to thereby permit the spring 45 to seat the valve 36 and cut off further gow of air from the tank to the primary reduction charn- Leading from the prima-ry reduction chamber 21 is a passage 70 which communicates with a bore 71 in which is threaded a demand valve seat member 72 which extends through suitably positioned openings in the diaphragm 50, the bottom wall of the intake housing 51, and the spring retainer 66 and the foot of a bracket 73 hereinafter described more in detail. The valve seat member 72 takes the place of one of the screws 52 and secures the bracket 73 in place. The valve seat member 72 is formed with a flange 74 seated against the bracket 73, and has a tapered seat portion at its outer end providing an annular seat of relatively small width. A bore 75 extends through the valve seat member 72 and provides communication between the bore 71 and the interior of the intake housing 51.

The valve bore 75 is normally closed by a demand valve formed of resilient sealing material such as rubber or a synthetic material such as Tetlon The valve 80 is carried by a lever 81 pivotally supported as at 82 from the bracket 73. Thus the valve 80 is adapted to be moved into and out of position in closing the valve port or passage 75. The valve S0 is normally urged into closed position by a spring which is seated at one end against the nut 58 and at the other end against the demand valve lever 81, the latter being formed with a boss or button 91 struck up from the material of the lever and which enters the corresponding end of the spring to retain the spring in its appropriate position relatively to the lever S1.

A second valve-operating lever 100 is pivoted as at 101 to a bracket 102 secured by one of thev screws 52, which lever 180 is adapted to operate the demand valve lever 81 to open the demand valve. The lever 100 has a boss or button 163 formed with its outer end adapted to be actuated by a breather diaphragm 105 hereinafter described. The valve actuating lever 100 is so arranged that it engages intermediate its ends and preferably about half way between its ends a boss or button 106 formed on the outer end of the lever 81.

lt will be seen from the foregoing that when the lever 188 is depressed it bears against the button 106 and effects a depression of the lever 81, which raises the de# mand valve tl'off its seat to permit air to iiow from the primary reduction chamber 21 to' the passage-70, the bore 71 and the portv75 and into the interior of the 'intake housing 51.

rlhe intake housing 51 and the valve operating or breather diaphragm 105 together delinev an intake chamber 118 which is connected to the interior of the flask through the passages hereinbefore described. The relative sizes of thepassages connecting the interior of the flask with the interior of the inlet chamber 110, and particularly the passages leading from the pressure reduction chamber 21 to the intake chamber 110, are such that the air is maintained in the intake chamber 110 at substantially the pressure of the medium surrounding ythe pressure regulator.

The intake housing is of generally cupped form and has a bottom wall 111 of circular form and a side wall 112 upstanding therefrom. Extending outwardly from the outer end of the side wall 112 is a ilange 113 having an upturned rim 114. The breather diaphragm 105 is formed from a suitable exible resilient material which is water-tight and which is not subject to deterioration over a long period of use, or loss of exibility and resilience, and preferably I form such diaphragm from rubber, reinforced with a nylon core. The breather diaphragm 105 has a central portion 115 which is rigid and nonflexible and which has secured thereto on both faces thereof circular reinforcing plates 116 of thin metal secured to the diaphragm in a suitable manner as by rivets 117. Outwardly of the reinforced portion is a tiexible resilient portion 116 of annular form and outwardly thereof is a securing rim portion 119 of greater thickness which is sealingly secu-red to the ange 113 of the intake housing 51 by screws 120 which extend through the flange 113 and are secured by nuts 121.

Disposed outwardly of and in clamping engagement with the rim portion 119 is a circular exhaust ring 125 of generally channel shape in cross-section and having a main wall or web 126 and

flanges

127 and 128 extending inwardly therefrom providing a generally U shaped crosssection.

Secured against the outer face of the ilange 128 of the exhaust ring is an exhaust diaphragm 136 which is generally similar in form and structure to the breather diaphragm 195 except as hereinafter explained. Out-v wardly of the exhaust diaphragm 136 is a cover 131 of generally disc-shaped form and having a wall portion 32, an inclined wall portion 133 extending therefrom in which is provided a plurality of openings 134. Outwardly beyond the wall portion 133 is a flange 135 having a downturned rim 135a. The securing screws 120 extend through the liange portions 135 and secure the cover 131 in place on the exhaust ring 125 and at the same time clamp the rim portion 136 of the diaphragm 130 between the flange 135 and the flange 128. The

diaphragms

130 and 105 deline therebetween an exhaust chamber 140 which communicates with the exterior of the pressure regulator through an exhaust valve now to be described.

The diaphragm 130 has a central portion 141 which is reinforced by reinforcing members 142 'secured by,

which preferably are disposed in a circumferential series about the center of the diaphragm 13G.

The exhaust openings `.145 are normally closed by an exhaust valve 146 which takes the for-m of a check valve which opens whenever the pressure in the exhaust chamber 148 is greater than the pressure on the exterior of the diaphragm 138. To this end the valve 146 is formed of suitable resilient material such as rubber, and has a circular portion 147 which normally overlies all of the openings but which is yieldable and is displaced away from the openings 145 whenever the pressure within the exhaust chamber 140 exceeds the pressure on the exterior face of the diaphragm. The valve 146 also has a stem portion 148 which extends through an opening in the'diaphragrn 138 and a head portion 149 which serves to retain the stem portion 148 in the diaphragm 131).

A push rod 156 of generally U shaped form is secured to the inner face of the diaphragm 13) by the head 149. The push rod is so dimensioned and positioned that when the diaphragm 130 is moved inwardly a suiicient amount the push rod 150 bears against the central portion of the breather diaphragm 105 and moves it inwardly for a purpose hereinafter described.

Extending from the inlet chamber 110 is an outlet connection 160 and extending from the exhaust chamber 140 is a similar inlet connection 161. The air hose 13 ir1- clude's an intake or inhale portion 162 connected as by a clamp 163 to the outlet connection 169 and an exhaust or exhale .portion 164 connected as by a clamp 165 to the connector 161. The two

hose portions

162 and 164 are formed of corrugated rubber hose of conventional form.

The connecting portions 16) and 161 may be formed as separate members and welded into suitable openings in the intake housing and exhaust ring respectively, or they may vbe formed integrally therewith.

Connected between the ends of the

hose portions

162 and 164 is the mouthpiece l14 now to be described. The mouthpiece 14 includes a tubular portion 173 connected at its ends respectively to the corresponding ends of the

hose portions

162 and 164 in a suitable manner, as by j hose clamps and 176 respectively, and having a bore 174 providing communication between the interiors of the

portions

162 and 164. Extending from the main body portion 173 of the mouthpiece 14 is a lateral portion 177.V

having a bore 178 extending therethrough and'leadin'g from the bore 174 to the exterior. The mouthpiece has the usual shield or apron 179 and tooth grip lugs 190.

The lateral portion 177 extends from the main body 173 in oiset relation thereto and above the medial plane passing through the axis thereof. Thus when the mouthpiece is in the normal position in the mouth of the user, the center of the bore 174 is disposed below the center line of the bore or passage 17S. Consequently, any saliva which enters the passage 178 from the mouth of the user, will pass downwardly into the lower portionr of the bore 174 and will be trapped therein and will not tend to return to the mouth of the user. The trapped saliva will be expelled from the mouthpiece during the exhalation cycle.

Disposed in the ends of the body 173 are check valves 181i and 181. The

valves

186 and 181 are identical in construction and are so arranged as to permit only a one-way flow of air through the hose. Thus the valve 18) permits how of air from the hose portion 162 into the bore 174 but not in reverse direction and the valve 181 permits the ilow of air from the bore 174 into the hose portion 164 but not in a reverse direction. Each valve includes a rigid cylindrical body portion 182 which is inserted in the end of the mouthpiece body 173 and secured therein by the resiliency of the material of the body 173 and the clamping action of the corresponding hose clamp. The portion 182 carries a partition 183 formed with a plurality of ports 184 preferably of segmental shape. The ports are normally closed, but each valve member has a head 185 which normally overlies the ports 184 but which is sui'liciently liexible and yielding to be displaced away from the ports 184 upon air pressure being applied thereto through the ports. The valve is secured in the partition by a stem 186 and a head 187.

The bodies of the

valves

180 and 181 preferably are formed of a rigid material such as a suitable rigid plastic, and the valve members 185 preferably are formed of a flexible resilient material such as rubber or synthetic rubber.

In the use of the device in accordance with my invention the pressure regulator, with the air hose and mouthpiece attached, is connected to a tank by the clamp 12, the clamping screw (not shown) being tightened so as to firmly clamp the outer end of the valve housing 22 against the neck 15 of the ilask in sealing engagement therewith and to thereby place the bore 30 in communication with the outlet passage 16 of the flask.

The shut-oil valve (not shown) is opened to admit air into the regulator from the ask. inasmuch as initially the pressure in the chamber 21 is at that of the medium surrounding the device, the spring 65 causes the pressure member 55 to urge the push rod 61 downwardly to -bear against the anvil 42 and maintain the valve 36 in open position. Thus the air from the ask may pass through the passage 16, the bore 30, the passages 38, the port 31, the bore 32 and the passages 63 into the chamber 21. Assuming the device to be in air, the pressure in the intake chamber 110 and the exhaust chamber 140 is equal and the diaphragm 105 is not displaced from its normal position. Accordingly, the demand valve 80 is in closed position and air cannot escape therethrough.

Thus the pressure in the chamber 21 builds up to the desired amount, namely around 50 to 100 pounds per square inch. When this occurs the diaphragm 50 is forced outwardly against the force of the spring 65 a suicient amount to permit the valve 36 to close and cut olf any further flow of air from the flask 10.

The user inserts the grip lugs 190 in his mouth and between his teeth with the shield 179 between his lips and his teeth so that there is no leakage of air past the mouthpiece. The exhaust diaphragm 130 is subjected to the pressure of the surrounding medium, whether it be air or water. Assuming now that the user has entered the water and the body of the user and the pressure regulator are submerged in the water at a predetermined depth, the water exerts a pressure on the exhaust diaphragm 130 determined by the depth at which the pressure regulatorand more particularly the diaphragm 13G-is located.

Assuming that the user is neither exhaling nor inhaling, the apparatus is in what I term the static condition wherein the demand valve 80, the

check valves

180 and 181, and the exhaust valve 146 are closed and the

diaphragms

105 and 130 are in their normal neutral positions. The pressures throughout the device then are equalized. The water pressure exerted on the outer face of the diaphragm 130 tends to displace the diaphragm 130 inwardly a very slight amount and, owing to the resiliency of the diaphragm, it is stressed in a direction setting up a counter or restoring force on the diaphragm, tending to restore it to its original position. On the inner face of the diaphragm there is an air pressure force equal to the water pressure force on the outer face of the diaphragm less the counterforce tending to restore the diaphragm to its initial position. In other words, the force exerted by the air pressure on the inner face of the diaphragm 130 is less than the force exerted by the water pressure by the amount corresponding to the energy stored in the diaphragm by reason of its displacement and tending to restore it to its normal position and condition.

Since the pressure in the exhaust chamber is slightly less than that of the surrounding medium, and since the user is neither inhaling nor exhaling, the exhale valve 181 may open slightly and similarly the inhale valve 180 may open slightly to equalize the pressure within the intake chamber 110 and the exhaust chamber 140. When the pressure is thus equalized the breather diaphragm 105 is in its neutral position and the demand valve remains closed. Thus the pressure throughout the system is equalized at a value equal to the pressure in the exhaust chamber, which is slightly less than that of the surrounding water.

When -the user inhales, the inhale valve 180 (as shown in FIG. 3) is opened to allow air to pass therethrough to the mouthpiece and into the lungs of the user. This action reduces the pressure within the intake chamber 110, whereupon the breather diaphragm 105 is drawn inwardly and bears against the button 103 to rock the lever which in turn rocks the lever 81 and fully opens the demand valve 80. The inward movement of the diaphragm causes a reduction in pressure in the exhaust chamber, and the exhaust diaphragm moves inwardly accordingly. The reduction of pressure in the intake chamber and consequent inward movement of the diaphragm resulting from the inhalation causes the valve 180 to be opened so that the air can flow through to the lungs of the user. The valve 181 remains closed. Air flows from the pressure regulator chamber 21 into the intake chamber 110 in a quantity sufficient to meet the demand of the inhalation by the user.

Upon the cessation of the inhalation by the user the check valve 180 closes and pressure is built up in the chamber 110 until the diaphragm 105 is returned to its initial position (as shown in FIG. 2) and allows the demand valve 80 to close, whereupon no more air ilows from the primary chamber 21 into the intake chamber 110. The diaphragm 105 also returns to its original position.

When the user exhales the exhale valve 181 is opened (as shown in FIG. 4) and air passes therethrough and through the hose portion 164 into the exhaust chamber 140. The increase in pressure in the exhaust chamber moves the diaphragm 130 outwardly and finally causes the exhaust valve 146 to open and allow air to be discharged to the exterior of the regulator and into the surrounding water through the opening 145. Saliva trapped in the lower portion of the bore 174 will be expelled through the valve 181 by the exhalation of the user. The inhale valve is maintained closed during the exhale portion of the cycle.

During the exhale portion of the cycle the exhaust diaphragm 130 is moved outwardly as above described, and the exhaust valve 146 is opened. At the same time, owing to the pressure established in the exhaust chamber 140, the breather diaphragm 105 is moved inwardly a slight amout to open the demand valve slightly and equalize all pressure in the inhale hose portion 162 with that in the remainder of the device. This equalizing of pressure assists in exhaling because the user does not have to exhale against the entire pressure of the exhaust valve, but his exhalation is assisted by the pressure of the air passing through the hose from the intake chamber.

During normal use of the device the push rod 150, carried by the exhaust diaphragm 130, remains spaced from and out of engagement with the breather diaphragm 105. However, should the device be submerged substantially-that is to say, for example, a distance of several feet under the surface of the water without any inhalation by the user-the pressure of the water will cause the exhaust diaphragm 130 to be moved inwardly to an extent to which the push rod effects inward movement of the end of the lever 100 and thereby opens the demand valve S0 to allow air to pass into the intake chamber and through the inhale valve and into the lungs of the user. Thus even should the user forget to inhale, air will be supplied to his lungs and will cause involuntary ac- 9 tion which will result in the user exhaling and initiating the breathing cycle.

It will be noted that the breather diaphragm 1105 is not exposed to contact with the surrounding water but is exposed to air on both sides. The outer face of the breather diaphragm 105 is subjected to the pressure of the air in the exhaust chamber which is at the exhaust pressure or a lesser pressure, depending upon the portions of cycle at any moment. The inner face of the breather diaphragm 105 is subjected to a maximum pressure equal to the pressure of the air passing from the orifice 75 of the demand valve.

The breather diaphragm, which is the diaphragm against which the user must exert the pressure of his lungs in order to actuate the diaphragm is exposed only to air on each facev thereof. It is not exposed to water pressure. Accordingly the breather diaphragm may move relatively freely during both the exhale and inhale cycle as the only inertia is that of the diaphragm itself and of the air. On the other hand, in a conventional underwater breathing device the water pressure is always applied against the `outer face of the breather diaphragm and consequently upon inward movement of the diaphragm the water inertia -tends -to continue the inward movement of the diaphragm. On the other hand, upon the initiation of the outward movement of the diaphragm the initial inertia of the water must be overcome. In the present device there is no water inertia to be overcome or to effect continued inward movement of the diaphragm.

The elimination of the aforesaid water inertia on the breather diaphragm results in a more uniform breathing action and less resistance =to the normal breathing action. Thus the device of the present invention is more comfortable and satisfactory to use inasmuch as the user does not have to exert any abnormal inhale and exhale force to operate the device as in the case of prior devices.

It will be noted that the breather diaphragm in the device of the present invention is not subjected to the pressure of the water. Accordingly there is no tendency for the diaphragm to be tilted or cocked when the device is in such position that one outer or peripheral portion of the diaphragm is at a lower depth than another peripheral portion. Accordingly, the demand valve is opened only when such action is dictated by the desired pressure in the intake chamber resulting from the inhale cycle and there is no possibility of the demand valve being opened or held against opening owing to any diierential in water pressure `over the different portions of the face of the breather diaphragm.

The exhaust diaphragm 130 also is provided with a rigid central portion and this diaphragm moreover does not normally act to operate the demand valve. However, should the device be in such position that there is a greater pressure on one peripheral portion thereof than on another owing to the position of the diaphragm and to the fact that the water pressure on one peripheral portion is greater than on another, nevertheless because of the fact that the push rod 150 is located centrally of the exhaust diaphragm and acts on the exact central portion of the breather diaphragm there will be no actuation of the demand valve because of any such differential pressure exerted by the water on the exhaust diaphragm 130.

It will be seen that inasmuch as the breather diaphragm M is not subjected to the pressure of the water surrounding the regulator, there is no danger of any spontaneous loss of air by reason of the fact that a greater pressure is exerted on the breather diaphragm than is exerted on the exhaust valve. Accordingly, it is immaterial whether the exhaust valve be placed above or below or any particular distance above the breather diaphragm. While I have shown a device wherein the exhaust valve is placed relatively close to the breather diaphragm, this is not at all necessary and the exhaust valve may be placed at any location above or below the breather diaphragm. Accordingly, it is immaterial what 10 position the device takes relatively to the water in which it is located. Thus the user may swim in the normal face down position, or on his back, or in any other position without causing spontaneous loss of air through the exhaust valve.

The device of the present invention requires a miniexhaust valve and equalizes all pressures from the inlet chamber to the exhaust valve.

inasmuch as the breather diaphragm of the present invention is not subject to cooking or water inertia and since it is eiective only at the center thereof to open the demand valve, the diaphragm may be made comparatively larger than diaphragms employed in prior art devices and therefore is muchmore sensitive than smaller diaphragms.

The provision of two diaphragms provides a double protection for vthe device. For example, should the breather diaphragm be ruptured or leak, the outer, exhaust diaphragm would then functionl both as a breather diaphragm and as an exhaust valve diaphragm and the device would operate even though the breather diaphragm were not effective. Thus, even though the inner diaphragm were ruptured or otherwise become ineffective, the user would still be able to operate the demand valve by the normal breathing operation and would be supplied with air to permit his return to the surface. Also, if the outer, exhaust diaphragm should be ruptured or otherwise caused to leak, the device would still operate. Under such circumstances, the breather diaphragm would continue to operate but would be subjected to the pressure of the water thereon. In this event the exhale valve 181 would function as the exhaust valve, and the breather diaphragm 10S would be subjected to the pressure of the water on the outer face thereof as in the case of conventional prior art underwater breathing devices.

It will be seen from the foregoing that the device of my invention is relatively simple, and no parts thereof require any critical adjustments. The simplicity thereof will assure long life without costly repairs and it can be manufactured and assembled readily. Moreover, it is extremely safe and positive in action, and provides not only all of the features and advantages of prior devices but embodies a number of features not present or possible in devices constructed in accordance with prior art teachings. It provides extremely easy breathing and furnishes air instantly to the user in any quantity desired.

The mouthpiece is of such construction that the valve chamber serves as a saliva trap from which the saliva is expelled by the exhaled air during the exhalation portion `of the breathing cycle. Moreover, the valve chamber is depressed, and thus does not interfere with the face mask customarily worn by the user of the breathing device.

While I have referred to the device herein as being employed to supply air to the user, it will be understood that the device is not restricted to such use but may be employed to supply any breathable gas to the user. For example, under certain circumstances it may be desirable to provide in the tank or ask a breathable gas consisting of air enriched with oxygen, or pure oxygen. It will be understood that the mechanism of the device does not depend upon the nature of the gas supplied by the flask, but it is suitable for operation with any breathable gas.

I claim:

l. Breathing apparatus comprising a casing, a first respiration-responsive diaphragm defining with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, a normally routlet passage connecting said dreduction intake chamber, a normally closed demand valve actuated closed intake valve controlled by said first diaphragm for controlling the supply of gas to said intake chamber, a second respiration-responsive diaphragm defining with said casing and said first diaphragm an exhaust chamber and exposed on its outer face to the surrounding fiuid medium, a normally closed exhaust valve in said second diaphragm, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point` of use, and check valves in said conduit on opposite sides of said opening.

2. Breathing apparatus comprising a. casing, a first respiration-responsive diaphragm defining with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, a normally closed intake valve controlled by said first diaphragm for controlling the supply of gas to said intake chamber, a second respiration-responsive diaphragm defining with said casing and said iirst diaphragm an exhaust chamber and exposed on its outer face to the surrounding fluid medium, a normally closed exhaust valve in said second diaphragm, means extending inwardly from said second diaphragm positioned to engage said first diaphragm to cause it to open said intake valve when the pressure of the surrounding fiuid medium exceeds the pressure in said second chamber by a predetermined amount, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point of use, and check valves in said conduit on opposite sides of said opening.

3. Breathing apparatus comprising a casing defining a pressure reduction chamber having an inlet adapted to be connected to a source of breathable gas under pressure, a valve controlled by the pressure in said reduction chamber for controlling the admission of gas into said reduction chamber, a first respiration-responsive diaphragm deiining with said casing an intake chamber, means defining an outlet passage connecting said reduction chamber and Said intake chamber, a normally closed demand valve actuated by said first diaphragm for controlling the fiow of gas from said reduction chamber to said intake chamber, a second respiration responsive diaphragm defining with said casing and said first diaphragm and exposed on its outer face to the surrounding fluid medium, an exhaust chamber, a normally closed, exhaust valve in said second diaphragm, a conduit connected between said intake chamber and said exhaust chamber and having an opening intermediate its ends for connecting said conduit to a point of use, and intake and exhaust check valves in said conduit on opposite sides of said opening respectively.

4. Breathing apparatus comprising a casing, a first respiration-responsive diaphragm defining with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, a normally closed intake valve controlled by said first diaphragm for controlling the supply of gas to said intake chamber, a second respiration-responsive diaphragm defining with said casing an inclosure for said first diaphragm and defining with said first diaphragm and said casing an exhaust chamber said second diaphragm being exposed on its outer face to the surrounding iiuid medium, an exhaust opening leading from said exhaust chamber, a normally closed exhaust valve controlling said exhaust opening, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point of use, and check valves in said conduit on opposite sides of said opening.

'valve controlled by the pressure in said reduction chamber for controlling the admission of gas into said reduction fchamber, a first respiration-responsive diaphragm defining with said casing an intake chamber, means defining an chamber and said by said first diaphragm for controlling the fiow of gas from said reduction chamber to said intake chamber, a second respiration-responsive diaphragm defining with said casing an inclosure for said first diaphragm and defining with said rst diaphragm and said casing an exhaust chamber said second diaphragm being exposed on its outer face to the surrounding uid medium, a normally closed exhaust valve in said second diaphragm, a conduit connected bctween said intake chamber and said exhaust chamber and having an opening intermediate its ends for connecting said conduit to a point of use, and intake and exhaust check valves in said conduit on opposite sides of said opening respectively.

6. Breathing apparatus comprising a casing of generally cup shape, a first respiration-responsive diaphragm extending across the open end of said casing and secured to the casing to define therewith a space inclosed from the surrounding :fluid medium, said first diaphragm being exposed in its outer face to the surrounding fiuid medium, a second respiration-responsive diaphragm disposed in said inclosed space and extending across and secured to said casing to define with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, said second diaphragm being in spaced, face-to-face relation with said first diaphragm and defining with said casing and said first diaphragm an exhaust chamber, a normally closed intake valve in said intake chamber, means actuated by said first diaphragm for actuating said intake valve, an exhaust opening leading from said exhaust chamber, a normally closed exhaust valve controlling said exhaust opening, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point of use, and check valves in said conduit on opposite sides of said opening.

7. Breathing apparatus comprising a casing, a first respiration-responsive diaphragm extending across and secured to said casing to define with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, a second respiration-responsive diaphragm extending across said casing and secured to the casing to define therewith a space inclosing said first diaphragm from the surrounding fluid medium, said diaphragm being exposed in its outer face to the surrounding uid medium, said second diaphragm being in spaced faceto-face relation with said first diaphragm and defining with Said casing and said first diaphragm an exhaust chamber, a normally closed intake valve in said intake chamber, means actuated by said first diaphragm for actuating said intake valve, an exhaust opening leading from said exhaust chamber, a normally closed exhaust valve controlling said exhaust opening, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point of use, with check valves in said conduit on opposite sides of said opening.

8. Breathing apparatus according to claim 7 wherein said second diaphragm carries a projection positioned to engage said iirst diaphragm to cause the latter to open said intake valve when the pressure of the surrounding medium exceeds the pressure in said exhaust chamber by a predetermined amount.

9. Breathing apparatus comprising a casing, a first respiration-responsive diaphragm disposed in and secured to the casing to define therewith a space enclosed from the surrounding uid medium, said first diaphragm being exposed in its outer face to the surrounding fiuid medium, a second respiration-responsive diaphragm disposed in said space and extending across and secured to said casing to define with said casing an intake chamber adapted to be connected to a source of breathable gas under pressure, said second diaphragm being in spaced face-to-face relation with said first diaphragm and dening with said casing and said first diaphragm an exhaust chamber, a normally closed intake valve in said intake chamber, means actuated by said first diaphragm for actuating said intake valve, an exhaust opening leading from said exhaust chamber, a normally closed exhaust valve carried by said second diaphragm controlling said exhaust opening, a projection on said valve positioned to engage said first diaphragm to cause it to open said intake valve when the pressure of the surrounding uid medium exceeds the pressure in said exhaust chamber by ya predetermined amount, a conduit connected between said chambers and having an opening intermediate its ends for connecting said conduit to a point of use, with check valves in said conduit on Opposite sides of said opening.

References Cited in the le of this patent UNITED STATES PATENTS Ryan Jan. 13, McCaa Apr. 19, Seeler May 13, Holmes Sept. 2, De Sanctis I an. 31, Fay Aug. 7, Page Feb. 18, Adams Jan. 12,

FOREIGN PATENTS Great Britain July 2, France Sept. 13,