Dual Layer Cellular Inflatable Pad

Abstract

A dual layer cellular inflatable pad having the cells of each interfitting with the cells of the adjacent layer. The cells of one layer may be alternately inflated and deflated. The layers have a manifold across and adjacent the longitudinal cell ends with a small continuation of the cells on the end sealed side of the manifold to prevent arching or curling of the pad.

Description

BACKGROUND OF THE INVENTION

This invention relates to a dual layer cellular pad for supporting the human body and particularly to such a dual layer cellular inflatable pad wherein at least one of the layers may have a plurality of alternately inflatable cells which are inflatable at relatively low pressure to support a human body and which minimize lateral or shear movement of the skin as the alternating inflation takes place.

Persons suffering from serious and prolonged illnesses or injury may have to remain substantially motionless for extended periods of time either in a bed or in some other type of support such as a wheel chair. During such long periods of motionlessness, a common problem for such convalescing patients is the occurrence of decubitus ulcers appearing on the skin of the patient, commonly known as bed sores. The decubitus ulcers may be formed because of a prolonged deficiency in blood circulation at certain pressure points of the patient's body upon which he is resting. The decubitus ulcers are unsightly, painful and give rise to patterns of infection since they are open sores on the patient's body. Moreover, decubitus ulcers are difficult to heal if there is continued impairment of blood circulation around the area of the ulcer. Further, any frictional movement against the ulcers may cause them to break open and further complicate the healing process. Thus for a patient already suffering decubitus ulcers the shear motion between the body support and the patient's skin will complicate and retard the healing process.

There have been several prior art approaches to the prevention and/or the treatment of patients suffering from such ulcers. One such approach has been to place the patient on a water mattress which has a large flexible envelope filled with water and upon which the patient rests. The water bed thus permits the weight of the patient to be spread over the entire body area and eliminates pressure points at which circulation would be impaired and decubitus ulcers likely to form. Such a water bed however, is expensive and is very difficult to handle due to the weight of the water in it. Further, because of the weight of the water, a supporting structure for it must be fairly expensive. Still further, such water beds are subject to leaks and puncture and sanitation problems arise because if they are to be re-used they must be scrubbed and sterilized for each successive patient.

Another approach to the problem has been the provision of a pad of various blown or foamed polymeric materials with sufficient compressibility to permit a spreading of the body supporting pressure points. Such supporting pad structures, however, may be expensive and are difficult to clean when such foam covered pads are supported by alternately inflated tubes or cells. The shear effect on the patient's skin from the alternate inflating and deflating of inflatable portions of the structure may also tend to reopen the healing decubitus ulcers of the patient.

Cellular alternately inflatable single layer pads have also been used without a thick foam covering but such pads also have been subject to the problem of skin shear of the patient with the alternate inflation and deflation of the tubular cells of the pad. Such cellular pads generally require air pressures of around two pounds per square inch to support an adult human body. With the necessity for such air pressures the pads can feel relatively hard to the patient and are a source of discomfort.

In inflatable structures such as a pad or piece of furniture, a problem is encountered when a series of substantially parallel inflatable cells terminate at a manifold along an edge or end of the structure. The end area tends to fan out and causes arching of the structure along the end or edge. Thus such cellular inflatable structures do not lie flat and they are unsightly as well as being less desirable from a functional standpoint.

Accordingly, it is an object of the invention to provide a dual layer fluid supported pad which is comfortable and is relatively inexpensive to manufacture and maintain.

Another object of the invention is to provide a pad of the above structure wherein the end or edge portions thereof have an adjacent manifold for inflation and wherein the end or edge portions are substantially flat.

A further object of the invention is to provide an inflatable dual layer pad wherein the cells of the upper layer nest with and are restrained against lateral movement by the cells of the lower layer.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

SUMMARY OF THE INVENTION

The invention comprises a dual layer cellular fluid pad wherein the two layers of the pad are sealed together around their periphery in registration with the elongated cells interfitting one with another from layer to layer. At least one and preferably the lower pad may be filled with a liquid or a fluid. It has been found that the dual layer pad of the invention permits the use of substantially less pressure to support a given weight without bottoming than had heretofore been required in a single layer cellular inflatable pad. Thus the invention makes possible the use of lower pressure and provides a more comfortable pad than those prior art pads which require higher air pressure to support the human body without bottoming. The preferred material for the pad of the invention is a heat sealable polymeric material such as polyvinyl chloride. Further, the heat sealable polymer provides a pad surface which can easily be kept clean.

In the alternating pressure pad embodiment, at least one layer of the pad is formed with two air manifolds and two separate air pressure ports for inlet and exhaust. These manifolds then communicate with alternate elongated cells of the pad layer and can be inflated and deflated in timed relation to provide a therapeutic action for comfort and/or for reducing decubitus ulcers in bedridden patients. Further, the pad cell surfaces adjacent the body tend to conform to the body when the alternating deflation/inflation cycles take place, thus reducing shear on the body to prevent aggravation of decubitus ulcers in bedridden patients.

The interfitting of the elongated cells of the upper layer with those of the lower layer restrains the upper layer cells from spreading under load. Such spreading in prior art pads has been a cause of shear between the pad and the body.

Other embodiments of the invention may be used, for example, as a seat pad for truck or bus drivers or wheelchair patients wherein the alternately inflated cellular pad may be used for comfort. Further, a dual layer cellular pad may be used without the alternate inflation feature as an air mattress or seat pad in applications where the low pressure in the pad and/or reduction of shear movement relative to the skin provides more comfort.

The dual layer concept of the invention may also be applied wherein cells of each layer are statically filled with fluid and sealed, or such pads may be inflated by mouth or other pump means.

The invention accordingly comprises an article of manufacture possessing the features, properties and relation of elements which will be exemplified in the article as hereinafter described and the scope of the invention will be indicated in the claims.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a broken plan view of a dual layer inflatable bed pad.

FIG. 2 is a sectional view taken along line 2--2 of FIG. 1 showing inflation of alternate cells in the upper layer.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 1 showing inflation of all cells in the upper layer.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 1 showing deflation of alternate cells in the upper layer in a pattern opposite that of FIG. 2.

FIG. 5 is a side elevation view of the pad shown in FIG. 1.

FIG. 6 is a sectional view taken along line 6--6 of FIG. 1.

FIG. 7 is a plan view partially broken away of a dual layer inflatable seat pad.

FIG. 8 is a schematic representation of the support and pressure points of a rounded object such as a human body on the dual layer pad of the invention.

FIG. 9 is a schematic representation of the cellular layers of the dual layer pad when supporting a weight having a flat surface.

Similar reference characters refer to similar parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The dual layer inflatable pad as shown in FIGS. 1 through 5 in general comprises an upper layer 10 and a lower layer 12 juxtaposed and sealed along at least two edges as at 14, 16. The material of the two layers is preferably a heat sealable polymeric material such as polyvinyl chloride.

The layers of the pad may be filled by a source of fluid pressure generally indicated at 18 having outlets 20, 22, 24 connected to inlets 26, 28, 30 respectively of the dual layer pad. As shown in FIG. 1 inlet 26 is connected to supply air or other fluid to cell 32 and through its connection with manifold 31 supplies air or other fluid to alternate longitudinal cells 34, 36, etc. across the width of the upper layer of the pad. Similarly, pad inlet 30 is connected to manifold 38 to supply the alternate longitudinal cells 33, 35, 37, etc. of the upper layer of the pad. As shown in FIG. 1, the head end of the bed pad is that adjacent manifold 38 while the foot end of the pad is adjacent manifold 31. On the foot end of the pad the longitudinal cells may be further split into cells having a smaller diameter such as cells 33a and b, 35a and b, and 37a alternating with longitudinal cells of similar diameters such as 32a and b, 34a and b, and 36a. Thus in the foot end of the pad smaller diameter longitudinal portions of the cells will be alternately inflatable for therapeutic action in the leg supporting area of the pad. A greater number of smaller diameter cells in the heel area is preferred since the heels exert more pressure per unit area and should be supported on a greater number of pressure points.

At the head end of the pad the main longitudinal cells 32, 33, 34, etc. may be split into smaller diameter portions 32c and d, 34c and d, and 36c, etc. for better support in the area of the manifold 38. Further, on both ends of the pad adjacent the manifold areas the end seal lines 40 and 42 may be undulated as shown to form continuations of the cellular structure of the main body of the pad.

As best seen in FIG. 1, cell continuations 40a and 42a are inflated from the manifolds 31 and 38 respectively. It has been found that by providing such cell continuations along the pad ends that the problem of buckling or arching of the pad end has been substantially obviated. The tendency for the pad end to fan out along the manifold area and to arch is relieved because the cell continuations provide a series of small relieved areas at points 40b and 42b along the manifold.

As to the lower layer 12 the elongated cells of that layer are in fluid communication with conduit 22 through connector 28 and interfit with the longitudinal cells of the top layer. For those embodiments utilizing a fluid other than air, such as a gas or liquid such as water, connector 28 may be connected to a source for gaseous fluids or the cells of layer 12 may be prefilled with, for example water, and thus sealed. Thus as shown in FIGS. 1-4 the cells of the lower layer may be kept statically inflated while the cells of the upper layer are alternately inflated and deflated as will be more fully explained hereinafter. Thus cells 44, 46, 48, 50, 52, 54, etc. of the lower layer 12 interfittingly support the upper layer cells 32, 33, 34, 35, 36, 37, etc. in the body portion of the pad. In the foot portion of the pad, as shown in FIG. 6, the lower layer cells are also formed into two longitudinal cells of smaller diameter and supportingly interfit with the adjacent smaller diameter cells of the upper layer of the pad.

In operating the pad as shown in FIGS. 1-6, the cells of the pad may be inflated at a pressure of from about 1.0 to 2.5 psi, and preferably from 1.4 to 1.8 psi from the pressure source 18. The cells of the lower layer 12 may be kept at a static pressure while the cells of upper layer 10 may be alternately inflated and deflated. All of the cells in the upper layer 10 are inflated through lines 20, 24 from air supply source 18 as shown in FIG. 3. By means of a timed valving arrangement in the supply source 18, alternate body cells 33, 35, 37, etc. are deflated while inflation pressure is maintained in alternate body cells 32, 34, 36, etc. The same inflation and deflation takes place in the corresponding smaller foot section cells as shown in FIG. 6. After a predetermined interval of, for example, four minutes, cells 33, 35, 37, etc. are inflated as shown in FIG. 3, and then alternate cells 32, 34, 36, etc. are deflated as shown in FIG. 4. After a period of again, for example, four minutes, the cells 32, 34, 36, etc. are again inflated as shown in FIG. 3, and then the alternate cells 33, 35, 37, etc. are deflated to again resume the configuration of FIG. 2. This alternating inflation and deflation cycle is continuously repeated to change the pressure points supporting a body on the top layer 10. The changing of the pressure points thus permits periodic circulation in the patient's body and greatly reduces or eliminates decubitus ulcers for bedridden patients. The air pressure required in the cells to support a body without bottoming is substantially less than that of present single layer cellular inflatable pads and provides a more comfortable body support.

As schematically shown in FIGS. 8 and 9, the cells of the dual layer pad tend to conform to the shape of the body resting upon the top layer, and with the inflation and deflation of the alternating cells of the top layer tend to adjust their shape to maintain contact without relative shear movement between the cell surface and the supported body.

The embodiment shown in FIG. 7 may be used as a seat pad and the form shown is particularly useful for convalescing patients, truck drivers, airline pilots, etc. As in the FIG. 1 embodiment, the dual layers 10a and 12a are superimposed one on another and are preferably joined together around their peripheries by a seal line 16a with the longitudinal cells of each layer interfitting adjacent cells in the adjacent layer.

Upper layer 10a comprises two manifolds 31a, 38a, each connected to a plurality of alternate longitudinal cells formed by a continuous seal line 60. Thus longitudinal cells 32e, 34e, 36e, etc. are all in communication with manifold 38a and are supplied from a source of air pressure through inlet 26a. Cells 33e, 35e, 37e, etc. are all connected to a source of air pressure through inlet 30a via cell 33e and manifold 31a.

As to the lower layer 12a, there may be provided two inlets 28a and b both connected through line 22a to a source of fluid, whereby cells of layer 12a may be filled together. Thus essentially the same heat sealing die may be used in the manufacture of layer 12a as is used for layer 10a. If desired a single inlet may be used for layer 12a if the cells are all to be filled from a single inlet.

In use, the seat pad shown in FIG. 7 may operate therapeutically with the connection of inlets 26a and 30a connected to alternating sources of air pressure. The sequence of inflation and deflation will be similar to that described above as to the FIG. 1 embodiment. Thus the therapeutic action of the pad in the inflation and deflation of alternate cells in the upper layer 10a contribute substantially to comfort of a person sitting thereon over extended periods of time. It enhances the circulation and comfort by alternating the pressure points supporting the weight of a person thereon. Further, since the lower pressures may be used in the dual layer pad with or without the alternating inflation feature, the pad is substantially more comfortable to sit on than are prior art single layer pads. The pad cells do not tend to separate, thus reducing relative shear movement as to the supported surface.

While a dual layer pad having a statically filled lower layer and with alternately inflatable upper layer cells has been shown, it should be understood that a number of variations may be employed within the scope of the invention. For example, the dual layer pad may be statically inflated in both its layers as an air mattress or seat pad. Further, the cellular arrangement may be varied in a number of ways wherein the cells of the lower layer will interfit with the cells of the upper layer to tend to hold those cells from spreading under a load. In such an embodiment, lower static pressures may be employed without bottoming under load.

It should also be understood that the term "inflatable" as used in the specification and claims includes the term "inflated" and that other fluids or liquids may be used instead of air within the scope of the invention.

It will also be apparent that in a number of applications the provision of short cell continuation along the sealed edge of the manifold will alleviate buckling or arching of the structure end or edge adjacent the manifold.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above article without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention which, as a matter of language, might be said to fall therebetween.

Claims

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An inflatable pad comprising:

A. a first inflatable cellular layer having

1. a first fluid manifold means connecting a first plurality of cells for inflation and,

2. a second fluid manifold means connecting a second plurality of cells for inflation,

B. a second cellular cushioning layer alternately interfitted with the cells of said first inflatable cellular layer in tangential relationship thereto,

1. the central plane of said second layer being spaced from the central plane of said first layer, and

C. inflation inlet means connected to said first and second fluid manifold means of said first layer, said second cushioning layer acting to support said first inflatable cellular layer.

2. The inflatable pad defined in claim 1 wherein said first and second cells of said first layer are elongated substantially over a lateral dimension of said pad in alternating parallel relationship and said cells of said second layer are similarly elongated and interposed in a parallel relationship with said cells of said first layer.

3. The inflatable pad as defined in claim 2 wherein said elongated cells are provided with branching ends terminating at a side of said manifold from the main body of said layer, with said manifold being adjacent an edge of said layer and wherein there are provided cell extensions on the other side of said manifold to alleviate buckling of said layer along said manifold when inflated.

4. The inflatable pad as defined in claim 1 wherein said inflation means comprises fluid pump means and valve means for alternately inflating and deflating said first and second cells of said first layer.

5. An inflatable pad assembly comprising:

A. a first inflatable layer having

1. a plurality of elongated inflatable cells,

2. first and second fluid manifold means for alternate independent inflation of said cells,

B. a second inflatable layer having

1. a plurality of elongated inflatable cells,

2. said second layer cells being of substantially the same diameter and length and being spaced apart substantially the same as said first layer cells,

C. said first and second inflatable layers being juxtaposed against and secured to one another,

1. with the cells of said first layer nesting between each of two adjacently positioned cells of said second layer,

2. the central plane of said second layer being spaced from the central plane of said first layer, and

D. fluid pressure means connected to said manifolds of said first layer cells comprising

1. fluid pump means for a source of fluid pressure and

2. valve means for inflating and deflating said cells of said first layer.

6. The inflatable pad assembly defined in claim 5 wherein said first inflatable layer is provided with a plurality of smaller diameter elongated inflatable cells each branching from the main elongated inflatable cells adjacent one end of said pad.

7. A dual layer pad for supporting a human body thereon, comprising:

A. a first layer having a plurality of inflatable cells substantially covering at least a portion of a body supporting surface thereof; and

B. a second cushioning layer juxtaposed against said first layer at the surface opposite said supporting surface,

1. the central plane of said second layer being spaced from the central plane of said first layer, and

2. said second layer supporting and interfitting with said cells of said first layer to retain same against lateral movement upon imposition of a body on said first layer.

8. In an inflatable structure having a plurality of longitudinal inflatable cells arranged substantially parallel to one another

A. means forming a manifold adjacent an edge of said structure and having a side thereof in fluid communication with each of said cells,

1. said manifold having said side positioned substantially across the ends of said cells and

B. means forming relatively short continuations of said cells on the other side of and in fluid communication with said manifold.

9. The structure defined in claim 8 wherein said cells are formed by seal lines and said cell continuations are formed by an undulating seal line along the manifold edge of said structure.