US 3605145 A
Description (OCR text may contain errors)
R. H. GRAEBE BODY SUPPORT sep; 2o, 1911 FiledA Dec 5'. 1568 2 Sheets-Sheet 1 l//l/ lll/lill l f f. Lf mi m6, e maw r IP R. H. GRAEBE sept. zo, 1911 BODY SUPPORT 2 Sheets-Sheet 2 Filed Dec. 5, 1968 mm f /'/|V/ Alf/ K FIG.6
United States Patent O 3,605,145 BODY SUPPORT Robert H. Graebe, 4 Signal Hill Blvd., East St. Louis, Ill. 62203 Filed Dec. 5, 1968, Ser. No. 781,472 Int. Cl. A47c 27/08 U.S. Cl. -348 11 Claims ABSTRACT OF THE DISCLOSURE A body support including a plurality of pliant outwardly extending air cells which are in communication with one another through a base. When loaded the air cells support the load with substantially the same force per unit area irrespective of the amount they are deflected.
This invention relates generally to cushioning devices and in particular to body supports for supporting a body in such a manner that the supporting force is distributed substantially uniformly over the portion of the body which is in contact with the support.
Conventional body supports such as mattresses or seat cushions generally employ a multiplicity of interdependent coil springs arranged on a base in a uniform pattern with a foamed or some other type of padding extending across their upper ends. Springs, however, resist the load placed upon them with a force proportional to the amount they are deflected. Consequently, those springs within a mattress which are deflected most bear against the body with the greatest force In the case of invalids, hospital patients, and others who are confined to beds or wheelchairs for extended periods of time, this characteristic of conventional spring mattresses or cushions can have deleterious effects, particularly on those areas of the individuals skin which bear most of the body weight. More specifically, painful decubitus ulcers or bed sores often develop at these locations by reason of the fact that capillary blood vflow at these areas is greatly restricted, and this is particularly true where the supporting contact is at a bony prominence.
Mattresses constructed from foams and other paddings as well as conventional air mattresses react similarly when subjected to loading, although the relationship between the deflection and load is not necessarily proportional. Nevertheless, certain limited areas of these matresses bear most of the body weight, as is the case with innerspring mattresses and cushions, and therefore such mattresses induce discomforting bed sores.
One of the principal objects of the present invention is to provide a body support which produces substantially uniform loading across the contact area of the body supported by it. Another object is to provide a body support which reduces the possibility of decubitus ulcer formation on the bodies of confined individuals to an absolute minimum. A further object is to provide a mattress or other body support which affords adequate ventilation of the skin through the body support itself. An additional object is to provide a body support which is of a simple, yet rugged, construction and is economical to manufacture. A still further object is to provide a body support which is comfortable for extended periods of time. Still another object is to provide a cushioning device 3,605,145 Patented Sept. 20, 1971 for absorbing relatively severe impacts. These and other objects and advantages will be apparent hereinafter.
The invention is embodied in a plurality of elongated air cells arranged in side-by-side relation and in close proximity to one another so that the combined upper surfaces of the elements form a substantially continuous supporting surface. Each air cell is adapted to resist a force applied against it with a reactive force substantially equal per lunit area to that exerted by other air cells regardless of whether or not the particular air cell is deflected the same amount as the other air cells.
The invention also consists in the parts and in the arrangement and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur:
FIG. l is a perspective view of a body support constructed in accordance with and embodying the present invention;
FIG. 2 is a fragmentary sectional view taken along line 2F2 of FIG. 1;
FIG. 3 is a fragmentary plan view of the body support;
FIG. 4 is an elevational view of the body support supporting a contoured load;
FIG. 5 is a perspective view of a modified body support;
FIG. 6 is a fragmentary sectional view taken along line 6 6 of FIG. 5;
FIG. 7 is a fragmentary sectional view of still another modified body support; and
FIG. 8 is a fragmentary plan view of the body support illustrated in FIG. 7.
Referring now to the drawings in detail, the numeral 2 of FIG. 1 designates a body support including a base 4 and a pliant section 6 on which the invalid, hospital patient, or other individual using the body support 2 is carried. The base 4, which can be either flexible or rigid,
is, in effect, a manifold and includes an upper wall 8 and a lower Wall 10 which are marginally connected by integrally formed side walls 12 and end walls 14. Intermediate the side and end walls 12, 14, the upper and lower walls 8, 10, are interconnected by a plurality of restraining ribs 16 having apertures 18 which provide communication between the chambers 19 formed within the base 4 by the ribs 16. One of the end walls 14 is provided with an inflation valve 20 which can be similar to a conventional tire valve. The upper wall 8 is provided with a plurality of orifices 22 arranged in longitudinally and transversely extending rows with the orifices 22 in adjacent longitudinal rows being staggered -with respect to one another. Should the upper wall 8 be pliable, it is desirable to make it non-elastic, and this can be achieved by embedding a flexible but non-elastic material such as cloth in an elastomeric wall forming substance.
The pliant section 6 includes a plurality of closely spaced parallel air cells 30 having substantially cylindrical side walls 32 which integrally merge at the upper ends into circular top walls 34. Along their lower margins the side walls 32 merge into a common connecting web 36 which, in turn, is vulcanized or adhesively secured to the upper surface of the upper wall I8 in surrounding relation to the orifices 22. In this connection, it should be noted that the web 36 maintains the air cells 30 in longitudinally and transversely extending rows `with the air cells of adjacent longitudinal rows being staggered to provide a greater number of air cells for a given surface area as best seen in FIG. 3. Moreover, the pattern established by the axial centerlines of air cells 30 is identical to that formed by the orifices 22 in upper wall 8. Since the web 36 is secured to the upper wall 8 in surrounding relation to the orifices 22, each orifice 22 opens upwardly into a different air cell 30. The circular top walls 34 of the air cells 30 are closely spaced and are disposed such that they form a generally continuous upper supporting surface on the pliant section 6.
Preferably the pliant section 6 is formed as an integral unit from a suitable substance such as latex rubber. The thickness of the substance at the cell walls 32 should not be so great as to impart large restoring forces to the cells when they are deflected. On the contrary, little if any restoring force should be imparted by reason of the natural resiliency of the material from which the walls 32 are formed. Ideally, the cells 30 of the pliant section 6 should not be free-standing, yet should be strong enough to resist ballooning when subjected to elevated internal pressures of the magnitudes encountered in the application for which they are designed. In the case of the latex rubber, it should be approximately 14 to 16 mils thick at the walls 32 and 34 of the cells 30.
One method of forming the pliant section 6 is to dip a pattern consisting of a flat base having a multiplicity of cylindrical elements projecting from it into a vat of liquid latex rubber. Ten to twenty dips are required to produce the desired wall thickness. After the latex has set, the pattern is removed leaving the pliant section 6 which is subsequently secured to the base 4 such that the orifices 22 open into individual air cells 30.
In use, the body support 2 is first inflated by directing air from a suitable source into the base 4 and air cells 30 through the inflation valve 20. If the base 4 is formed from a flexible substance, the restraining ribs 16 prevent it from ballooning outwardly into an elliptical shape. When the desired pressure is attained, the base 4 is placed on a supporting surface (not shown). If the body support 2 is to serve as a seat cushion, this supporting surface could be the seat or backrest of a wheelchair or other type of chair. -On the other hand, if the body support 2 is a mattress, then it is desirable to lay it on a plywood or other type of rigid supporting member which has previously been laid across the bed rails of a bed. Be that as it may, the base 4 may be placed directly upon a mattress of a bed and that mattress will provide sufllcient subjacent support. The base 4 can also be placed on a concave surface, in which case the axes of the air cells 30` would tend to out- Wardly converge. Accordingly, the cells 30 would be less likely to spread when subjected to loading.
The user, of course, rests on the generally continuous surface formed by the circular top walls 34, and in so doing he will deflect or crush the air cells 30 downwardly in conformity to the contour of his body as illustrated in FIG. 4. This deflection increases the pressure within the air cells 30 until an equilibrium condition is reached, at which point the user will be completely supported by the air cells 30. Since each air cell 30 is in communication with every other air cell 30 through the orifices 22, the chambers 19 and the apertures 18 ywithin the base 4, the pressure within each air cell 30 as well as the air pressure at any location within the base 4 will be the same. Inasmuch as the force applied by any one air cell 30` to the users body for all practical purposes equals the pressure within the air cell 30 multiplied by the area of its top wall 34, the force exerted by each air cell will be identical irrespective of the amount of deflection, assuming, of course, that all of the top walls 34 possess equal areas. Even if the areas of the top walls 34 are different, the force per unit area or pressure exerted by @h air Cell 30 on the supported body will be the same and that is the significant factor. Consequently, the portions of the users body which protrude furthest into the resilient section 6 will not bear an inordinate amount of his weight, while other portions escape without bearing hardly any of the weight at all. On the contrary, the supporting force exerted by the resilient section 6 on the users body will be distributed evenly over that portion of his body in contact with the air cells 30, and by reason of this fact, the forces on any one point are kept below the level (30 mm. of Hg) which normally impedes capillary blood flow to such an extent that bed sores develop. Moreover, air circulates freely through the voids between the air cells 30, and this not only permits dissipation of perspiration and the drainage of body wastes, but also has a general therapeutic effect on the users skin.
When both the base 4 and the pliant section 6 are constructed from a flexible material, the body support 2 can be used on the articulated frames of conventional hospital beds, in which case the regular mattress is used to provide subjacent support for the body support 2.
Also, the body support 2 can consist of several different modules having different internal pressures when unloaded for providing a firmer or softer support, whatever the case may be. For example, in a mattress it may be desirable to provide a somewhat firmer support in the pelvic and scapular regions than at the skull and heels. In such an instance a different module would be used for each region, and the air cells 30` and air chamber 19 of each module would be in communication with each other, but not with the air cells 30 and the air chambers 19 of adjacent modules. To a limited extent, the same effect can be achieved by altering the spacing between adjacent air cells 30 or by varying the cross-sectional size of such air cells. In this manner the supporting force supplied by the pliant section 6 is spread out over a greater or confined to a more limited portion of the skin. Be that as it may, the force per unit area exerted by the air cells 30 of any particular pliant section 6 still remains the same.
Air cells 30 between 4 and 6 inches in height and approximately 5%; inch in diameter have been found suitable for seat cushions, while greater heights up to 10 inches are desirable for mattresses. The cells 30 should be close as practical, 1/8 to 1A inch between cells 30 being acceptable.
Referring now to FIGS. 5 and 6, it is possible to provide a modified body support 50 including a base 52, a pliant section 54, and a peripheral restraining wall 56. The base 52 is very similar to base 4 and includes upper and lower walls 58, 60, the former of which is provided with a plurality of longitudinally and transversely aligned orifices 62.
The resilient section 54 consists of a plurality of upstanding air cells 64 of rectangular cross-sectional shape and arranged in longitudinal and transverse rows with the side faces of adjacent air cells 64 being normally in facewise, yet detached, abutment. The air cells 64 are, moreover, molded or otherwise formed from an open celled low density foam having little if any inherent resiliency when not otherwise supported. Urethane has been found suitable for this purpose. Each air cell 164 is provided with a downwardly opening compression chamber 66 which extends upwardly within that air cell 64, terminating in close proximity to its upwardly presented outer surace. The inwardly presented surface defining each compression chamber 66 is coated with a generally impermeable latex or vinyl plastic, as is the downwardly presented surface of each cell 64. As previously noted, the cells 64 are arranged upon base 52 with their side faces detached but in abutment, and when so disposed each orifice 62 opens upwardly into a compression chamber 66 so as to establish communication between the chambers 66 and the interior of base 52. The cells y64 are, moreover, held securely to the base 52 by means of a suitable adhesive located at the interface formed at the juncture of the upper wall 58 and the coated bottom faces of the air cells 64. Each air cell 64 is, furthermore, substantially `the same -height as neighboring cells 64 so that a more or less continuous supporting surface is formed across the upper portion of the resilient section 54.
The peripheral restraining Iwall 56 is formed preferably from a resilient foamed material of the open cell variety such as urethane so that air may pass through it and is secured to the base 52 in surrounding relation to the air cells 64 forming the resilient section 54, thereby lending lateral support to the cells 64.
After the body support 50 is inflated to the desired pressure, it is suitable for use in a manner similar to the body support 2, that is, with the user resting upon the rectangular upper surfaces of the air cells 64. Again, when this occurs the cells `64 will deform and depress downwardly in conformity to the contours of the users body until an equilibrium condition is attained, at which point each cell 64 will press upwardly against the users body with substantially the same force as the neighboring cells y64, thereby distributing the supporting force of the resilient member evenly across that portion of the users body in contact with it. Also, air circulates freely through the open cells of the open celled foamed material forming the air cells `64, as well as through the open cells of the peripheral wall 56, and this as previously noted has great therapeutic and comfort value.
Referring now to FIGS. 7 and 8, it is possible to provide still another modified body support 80 which is Very similar to the body support 2. The body support 80 includes a solid or flexible base 82 and pliant section 84, the latter of which integrally includes a multiplicity of air cells 86 arranged in longitudinally and transversely extending rows, with the cells in adjacent rows being staggered with respect to one another. Each cell 86 includes a circular top wall 88 and a frusto-conical side wall 90 providing an ever changing cross-sectional area dependent on deflection, which together define an air chambr 92. At their lower margins the side walls 90 merger into and are connected to one another through an integrally formed connecting web 94 which is adhesive or otherwise secured to the base 82. The air chambers 92 of adjacent air cells V86 are connected through embossed channels 96 formed within the web 94. In effect, the web 94 is contoured away from the base 82 to form the channels 96. Consequently, each air chamber 92 will be maintained at the same pressure irrespective of the amount its corresponding air cell 86 may be deflected. The pliant section 84 may be formed by dipping a pattern, in the manner previously described, or vacuum forming or similar techniques of production. The body support 80, having frusto-conical side walls 90, when used with a pliable base 82 will accommodate severe concave shapes such as would be required in football helmets.
By restricting the size of the orifice 22, the body support 2 can be adapted to absorb localized transient impacts of a severe magnitude without complete collapse of the air cells 30 at the point of impact. This is also true of the body supports 50 and '80. Restricted orifices or channels approximately the size lof a pin hole have been found particularly useful in adapting the body supports 2, 50 and 80 for use as shock absorbing package liners and in safety devices such as liners for safety helmets. Or crash protection systems in either case, when impacts of a localized nature are sustained, the air within the air cells at the point of impact cannot escape all at once into the air ychamber of the base or into adjacent unloaded air cells, and consequently the air cells at the point of impact give relatively slowly and separate the conformal static load from the dynamic loads, thereby absorbing the shock and distributing it over a relatively large area. Cell heights from 1A to l inch have been found suitable for use with helmet liners.
It should be noted that the air cells 30, 64, and 86 have 6 two degrees of freedom, that is to say they compress longitudinally aud may further be shifted laterally. Accordingly, they deflect laterally as well as longitudinally in the presence of body members and will not pinch or constrain those members.
This invention is intended `to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.
What is claimed is:
1. A cushioning device comprising base means forming a manifold, and a plurality of closely spaced elongated air cells mounted on the base means and projecting outwardly therefrom, the air cells having internal compression chambers and being pliable so as to have at least two degrees of freedom for longitudinal and lateral displacements whereby loads will deflect the air cells and reduce the volume of their chambers, the chambers of the air cells being in communication with the manifold so that the pressure within all the air cells will equalize when all or some of the air cells are subjected to loads.
2. A cushioning device according to claim 1 wherein the base means comprises first and second walls, located in spaced relation to one another in the formation of a continuous air chamber therebetween, wherein the first wall is provided with a plurality of apertures opening into the continuous air chamber, and wherein the flexible air cells are secured to the first wall adjacent their innermost ends in surrounding relation to the apertures, whereby the interior of each air cell communicates with the air chamber so that the air pressure within each air cell is equal.
3. A cushioning device according to claim 1 wherein each air cell comprises a body portion formed from an open cell cellular material, wherein the internal compression chambers open outwardly toward the base means, and wherein the inwardly presented surfaces defining the compression chambers are sealed with a substantially irnpermeable substance so that air cannot escape from the compression chamber through the open cells of the body portions.
4. A body support according to claim 3 wherein the cells are of polygonal cross-sectional configuration, wherein the side faces of adjacent cells are normally in facewise abutment, and wherein the outer surface of each cell forms a substantial continuation of the outer surface on adjoining cells, whereby a substantially continuous supporting surface is formed by the combined outer surfaces of the cells.
5. A body support according to claim 4 and further characterized by a peripheral wall mounted on the base means and extending around the outermost air cells, whereby to lend lateral support to the air cells.
6. A body support according to claim 1 wherein the air cells are connected to one another through a web attached to the base, and wherein the web is provided with air channels for establishing communication between the air cells.
7. A body support according to claim 6 wherein `the air channels are formed by embossments in the webs, the embossment being located in spaced relation to the base.
8. A cushioning device according to claim 1 wherein the manifold has a generally continuous wall extending across one side thereof, the wall having apertures providing communication with the interior of the manifold; and wherein the pliable air cells are attached at their inner ends of the generally continuous wall and have their interiors in communication with the interior of the manifold through the apertures.
9. A cushioning device according to claim 1 wherein the outer ends of substantially all of the air cells are detached from one another so that adjacent air cells can move laterally and inwardly and outwardly relative to one another.
10. A cushioning device according to claim 9 wherein adjacent air cells can move laterally in any direction relative to each other.
11. A cushioning device according to claim 8 wherein `the apertures are restricted orifices which are substantially smaller in area than the transverse cross-sectional area of the cells so that the conformal static pressures are separated from impact forces whereby the cells deflate slowly when impacts are sustained and thereby absorb the shock of the impact and distribute it over a large area.
8 References Cited UNITED STATES PATENTS BOBBY R. GAY, Primary Examiner 10 P. A. ASCHENBRENNER, Assistant Examiner U.S. Cl. X.R.