US 3042024 A
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Description (OCR text may contain errors)
w.. i we July 3, 1962 E. s. MENDELSON 3,042,024
INFLATABLE DOUBLE-WALLED RESUSCITATION GARMENT Original Filed June 26. 1959 IN V EN TOI/ States 2 Ciairns. (Cl. 12830) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the `United States of America for governmental purposes without the payment of any royalties thereon or therefor.
This application is a division of copending application Serial No. 823,265, rfiled June 26, 1959.
This invention relates to devices for facilitating articial respiration in the human body and particularly to chest respirators.
Ordinarily, chest respirators are concave shells that form an air tight chamber between the chest and the shell. Alternating positive and negative pressures applied in the chamber cause the chest to be forced inwardly and outwardly, as in breathing. The shell functions as a reaction member, for which purpose it must be sufficiently rigid to prevent it from being forced substantially out of shape by the changes in pressure that take place in the charnber. Necessary rigidity is supplied by making the shell of firm materials like sheet metal, plastics, etc.; but, although satisfactory for the purpose of resuscitation, their rigidity and bulk limit the extent to which they can be worn with any degree of comfort as a precaution against a quick need for artiiicial respiration. Usually they are Worn by the patient only during the time in which artiiicial respiration is being applied, and while he is in a supine position.
It is an object of this invention, therefore, to provide a new and improved chest respirator which is suitable for wear by an ambulating wearer.
It is also an object of this invention to provide a collapsible, inflatable, flexible chest resipartor capable of being worn as an ordinary garment when collapsed and readily inflatable to rigidity for the application of artificial respiration while the patient is in a supine or other position.
Other objects and advantages will become apparent from the description of the invention when read in connection with the accompanying drawings, in which- FiG. l is a longitudinal section through a respirator using the invention showing it during a period of negative pressure; `and FIG. 2 is siniilm to FIG. l, but shows the respirator in a period of positive pressure.
In a general way, the invention comprises a double walled, iniiatable shell or casing made of flexible, irnpermeable material adapted to enclose a portion of the body, as the thoracic area, for the application of artilicial respiration. The walls or panels of the shell are secured to each other at numerous points in a symmetrical pattern. Positive pressure introduced between the walls of the shell tends to extend it lengthwise into a stiffened form. Straps passed around the back of the body hold it thereto. The stiiiened shell is used as a reaction niember for cycling pressure.
The principle on which the shell stiffens or becomes rigid harks back to the law relating to pressure, wall tension, and radii; e.g., within a uid lilled distensible tube of circular cross-section and infinite length, as a balloon,
. pressure affects wall tension inversely with the radius.
The length of the shell in this invention is substantially atet greater than the distance separating the panels; therefore, its tendency to extend lengthwise will be greater than it is to widen. Consequently, it stiffens upon inflation.
Referring now to the drawing, a form of the invention is shown lin which the respirator is generally indicated by the numeral 1d. It comprises an inflatable shell or casing 12 designed to cover a desired portion of the body, as, the chest, and to assume a dished or concave shape upon inflation. The casing 12 has two panels, an inner panel 14 and an outer panel 16, of suitable material which is llexible and 'air impermeable. A rubber coated fabric is considered satisfactory for panel 16, however, the inner panel, 14, is of rubber, being air impermeable and extensible. The peripheral edges 17 of the panels 14 and 16 `are joined together by an adhesive, vulcanizing or other suitable means so as to form an inflatable chamber 1S 4between the panels. At numerous points, 2i?, the panels, 14 and 16, are fastened together in a suitable manner, the purpose of which will be apparent hereinafter. it is preferred that fastening points 2i) be uniformly spaced according to a pattern, for instance, parallel rows of evenly spaced points that are staggered in relation to those in adjacent rows.
A peripheral portion 21 of the casing 12 is inwardly turned under itself, the edges 17 thereby being well under the inner panel 14 along with a part of the iniiatable charnbr 18. The portion 21 provides a means of sealing the casing 12, upon iniiation, to the body of the patient.
Straps, not shown, secured to opposite sides of outer panel 16 of the casing 12, as by stitching, not shown, are adapted to extend around the patient and to be joined by an adjustable buckle, to provide a means for holding the casing on the body.
The respirator is designed to be worn conveniently in a collapsed condition either over or under the clothing of the patient, since it attens substantially completely and is flexible. When donned, it is readily inflated and casing 12 thereupon takes la rigid concave form (FIG. 1), since the extent of relative separation of the panels 14 and 16 is limited yby the fastening points 21B. The turnedunder portion 21 is pressed against the body by the inliating pressure within chamber 18 sealing the chamber 19 between the inner panel 14 and the body. Alternating positive as well as negative pressure may then be applied to the covered part of the body.
A tube 28 terminates in the outer panel 16 providing communication for the alternating pressure source with chamber 13 between panels 14 and 16. The source of alternating pressure may lbe a motor driven apparatus or `a suitable, manually operated device like the bellows 31 shown schematically. The latter is preferred for maximum portability. Two check valves, 38 and 40 are provided in the line 2S from the bellow 31. Valves 38 and 40 check opposite flows between bellows 31 and the casing 12. Valve 3S can be adjusted by adjusting means 41 to open only under pressures exceeding a selected pressure.
The construction Iaects the functioning of the respirator in that the alternating pressure from source 30 is used to keep the shell or casing 12 inllated as well as producing pressure differences on the chest. Furthermore, outer panel 16 alone behaves as a reaction member; whereas, the inner panel 14 acts like a diaphragm through which positive pressure can be applied to the body. During periods of positive pressure panel 14 contacts the body (FIG. 2), and in negative pressure periods it is raised above it (FIG. 1).
In operation, air iiow toward casing 1.2, produced by compressing bellows 31, passes through check valve 3%; its pressure readily overcomes the spring pressure of valve 38 tending to keep it closed. Air flow from casing 12 toward the bellows 31, normally produced with expansion of the bellows, is cut olii' by valves 38 and 4t) until casing 12 contains a predetermined pressure sullicient to inflate it to rigidity. This condition having been attained, air flow from casing 12 passes through check valve 40 as required for negative pressure application to the body. Thus, au initial period of operation of bellows 31 is used to inflate casing i2; thereafter, compressing bellows 12 overinates casing 12 causing inner panel 14 to distend laterally to contact the body applying la positive pressure thereto; extending the bellows 31 withdraws air from casing i2 (through valve 40) raising panel 14 out of contact with the body and thereby applying a negative pressure to it.
It will be understood that it is not intended to limit this invention by theories offered to explain it, and that many of the elements, as the bellows, the valves, etc. are of usual construction and well known in the art; they may or may not be of the type shown and described in illustrating the invention. Consequently, it is intended that all matter container in the above description, or shown in the accompanying drawings, shall be interpreted as illustrative only and not in a limiting sense.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specioally described.
What is claimed is:
1.. A chest respirator comprising a collapsible, inatable casing adapted to cover a portion lof the body, said casing having lan outer panel of air impermeable, rubber coated fabric superimposed on an inner panel of extensible, vair impermeable material, said panels secured to each other at their peripheral edges to `form a charn- -ber therebetween, a plurality of uniformly spaced means securing said panels to each other at spaced points thereof for limiting separation of said panels with inflation of said chamber, means for introducing an alternating pressure between said panels, whereby said easing is rigidly inflated and said inner panel is moved inwardly to contact said body under positive pressure and outwardly away therefrom with negative pressure applying a breathing action to the body and said outer panel functions as a reaction member, a conduit :connecting said means for introducing an alternating pressure between said panels and said casing, and check valve means in said conduit for maintaining a minimum pressure in said casing whereby said casing functions as a reaction member during negative and positive cycles.
2. The `device of claim l wherein said means for introducing alternating pressure is a portable bellows.
Rererences Cited in the le of this patent UNITED STATES PATENTS 2,588,192 Akerman Mar. 4, 1952 y2,676,587 Corcoran Apr. 27, 1954 2,818,853 Huxley Jan. 7, 1958 OTHER REFERENCES Ser. No. 347,414, Diena (A.P.C.), published May 11,