US 3138154 A
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Description (OCR text may contain errors)
June 23, 1964 o. E. HEDBERG 3,138,154
BREATHING DEVICE Filmfan. 23. 1961 j INVENTOR A my EMA/5L HEMEPG, k BY WMM( @mi ATTORNEYS United ,Statesr Patent O 3,138,154 BREATHING DEVICE Oscar Emanuel Hedberg, Lidingo, Sweden, assigner to Svenska Aktiebolaget Gasaccumulator, Lidngo, Sweden, a corporation' of Sweden Filed Feb. 23, 1961, Ser. No. 91,131 Claims priority, application Sweden May 13, 1960 4 Claims. (Cl. 12S-142) The present invention relates toa breathing device, which is adapted for use preferably under water or in a non-breathable atmosphere, such as by remen. Known devices for such purposes usually comprise an inhalation valve which is controlled by a membrane. The membrane is influenced on the one side by an ambient medium and on the other side by the pressure existing in a chamber connected to the breathing passages of the wearer. The chamber may be connected with a mouthpiece or with a facemask. The closing member of the Valve is preferably of resilient material such as rubber.
For a device of this type to be easy to handle it is essential that it has small dimensions, as a primary consequence of which the membrane area must be relatively small. At the same time, however, a more or less predetermined force is required to keep the inhalation valve closed and in order for the membrane to be able to develop this force, a reduction must be provided in the translation of the membrane movement to the valve, resulting in a corresponding increase in the force transmitted. If satisfactory closure of the inhalation valve is to be guaranteed then under all conditions, it is essential that the position of the membrane at which its actuation on the valve in the opening direction is initiated should remain xed. If this is not the case, only a portion of the movement of the membrane can be utilized for actuating the inhalation valve and the operation of the device will be unsatisfactory.
Previously known breathing devices provided with a closing member of resilient material in the inhalation valve have not been able to meet these requirements. The application of the present invention leads to a construction in which the actual position of the Valve member in the closed position of the valve is xed, whereby the entire movement of the membrane can be utilized for controlling the valve. According to the present invention, a portion of the Valve body, which is formed of a non-resilient material, is adapted upon closure of the valve to abut a xed stop, such as the valve seat, whereby there is obtained the desired accurate determination of the axial position of the valve body when the valve is closed.
'I'he invention will be described in more detail with reference to the accompanying drawing, FIG. 1 of which shows in section a part of a breathing device according to the invention and FIG. 2 a detail of the FIG. 1 device on an enlarged scale.
The breathing apparatus shown in the drawing is assumed to be connected at the moment under consideration with a mouthpiece 1, which surrounds a valve chamber 2. At one end of the chamber, breathing gas, such as air, is supplied through a nipple 3, the passage of which can be closed by an inhalation valve 4. This valve is controlled by a membrane 5 positioned at the other end of the valve chamber 2, the control taking place via a lever 6 which is mounted rotatably on a pivot 7. An exhalation valve 8 is mounted on the membrane 5.
The inhalation valve 4 in the embodiment shown is actuated in the opening direction by the gas ow and is biased by a spring 9 which substantially counteracts the pressure of the breathing gas flowing through the nipple 3, which pressure may be of the order of 5 kg./cm.2. In the embodiment shown, the spring 9 is therefore in the form of a pressure spring striving to close the valve 4 against the pressure obtaining in the passage 3. The spring 9 surrounds a valve stem 10, which has mounted on the free end thereof the pivot 7, on which the lever 6 turns. The short arm of the lever rests on a lixed support 11, so that the valve stem 10 and with it the valve body 12 will be unseated when the lever swings counterclockwise under the influence of the membrane 5. In order to step upy the force exerted by the membrane to the value required to actuate the inhalation valve 4, the spacing between the pivot 7 and the support 11 must be only a small fraction, such as 1/15 of the spacing between the pivot 7 and the point of contact between the membrane 5 and the lever 6.
As is more clearly apparent from FIG. 2, which shows the valve body 12 and the portion of the nipple 3 forming the valve seat on an enlarged scale, the closing member of the valve is an O-ring 13, which is inserted in a groove 14 in the valve body 12. The closing member is of resilient material, such as rubber, and as a consequence of this, the position of the valve body 12 in the axial direction when the valveis closed would not be accurately determined, unless special provisions are made, but would be dependent on the force with which the valve body 12 is pressed against the valve seat. In order to achieve accurately determined position of this kind, a portion of the valve body 12 which is assumed to be of non-resilient material is adapted to abut the valve seat, the latter serving then as a xed stop. This portion of the valve body 12 is formed by an annular extension 15 surrounding the O-ring 13. The dimensions of the arrangement are selected in such a way that when the valve body approaches the valve seat, the lO-n'ng 13 rst contacts the valve seat and provides the desired closure, whereupon the extension 15 reaches the valve seat and arrests the valve body 12 in an accurately determined position. The result of this is that` under all conditions it is possible to utilize the entire movement of the membrane for controlling the valve.
As is more clearly apparent from FIG. 2, the valve body 12 has a passage 16 extending from the high-pressure side of the valve to the inside of the 'O-ring to make the latter operate in the desired manner when the valve closes. Furthermore,` the valve body 12 has one or more passages 17 extending in the manner shown from the low pressure side of the valve to the space formed above the O-ring. The latter passages are provided to prevent the O-ring from being forced out of the groove 14 when the valve opens, which might occur if no such connection were provided between the space above the O-ring and the low-pressure side of the valve.
A further technical advantage accruing from the accurately xed position of the Valve body 12 is the constancy of the tightening pressure exerted by the spring 9 when the valve is closed. As a matter of fact, if the position of the valve body were to be determined by the resilient closing member 13, the result would be that for a larger than normal compression of the closing member, the spring would be extended, which would cause a decrease in the closing pressure exerted by it and possibly leakage of the valve. Through the accurately fixed position of the valve body this draw-back is avoided and the breathing device can be made to operate without any eifort from the wearer if the pressure of the spring is suitably selected and at the same time to be perfectly tight in the closed position.
The invention is not limited to the embodiment shown in the drawing, modications being possible within the scope of the following claims.
What is claimed is:
1. Breathing apparatus comprising a chamber having at one end a valve connected to a source of breathable gas, said valve having a movable and a fixed part for controlling gas delivered from the source to the chamber interior, a membrane forming a part of the chamber wall responsive to the difference between the pressure of the ambient medium and the pressure Within said chamber, lever means connecting said membrane and said movable part for controlling the inhalation valve by means of said membrane, gas outlet means for supplying gas from the chamber interior to a wearer, a closure member of resilient material mounted at one end of said movable part facing said xed part, said closure member tightly abutting said fixed part in the closed position of the valve, said movable part further having a portion of non-re silient material abutting said xed part when the valve is closed, the distance between said closure member and said xed part in the open position of the valve being smaller than the distance between said portion of non-resilient material and said fixed part of the valve.
2. Breathing apparatus as dened in claim 1 wherein said closure member is an `O-ring mounted in a groove in said movable part, a passage being provided between that part of the groove behind the O-ring and the low pressure side of the valve.
3. Breathing apparatus as defined in claim 2 including exhaust valve means whereby gas exhaled into said charnber by a wearer can flow out of said chamber.
4. Breathing apparatus as dened in claim 2 wherein said movable part is subjected to spring pressure which compensates for pressure exerted on said movable part by the gas.
References Cited in the tile of this patent UNITED STATES PATENTS 2,225,395 Young Dec. 17, 1940 v 2,384,669 Fields Sept. 11, 1945 2,523,906 Holmes Sept. 26, 1950