Flotation Apparatus

Abstract

This invention relates to improved flotation apparatus and, in particular, to beds and seats in which provision is made for bouyantly supporting the weight of the person on the bed or the seat, an object of this invention to provide improved flotation apparatus. This invention provides a flotation structure for buoyantly, or approximately buoyantly, supporting the weight of a patient's body by devices which weigh much less than previously known flotation devices.

Description

As is known, bedridden persons often develop bed sores, and to minimize this likelihood of developing bed sores, it has been previously proposed to buoyantly support the person, whereby the person's weight is supported over a large surface area, thereby virtually eliminating localized areas of high enough pressure to develop bed sores.

However, previously known buoyant supporting apparatuses, i.e., water beds, have been extremely heavy. The heavy weight has been due primarily to the fact that the water bed, in essence, comprises a large tank filled with water. For instance, in a tank measuring 7 by 3 by 11/2 feet, filled with water to a depth of one foot, the weight of the water alone is about 1,300 pounds. This water weight, plus the weight of the tank and its support, might be more weight than an old building could safely carry. It is, therefore, a further object of this invention to reduce the weight of the flotation apparatus by reducing the volume of fluid needed to buoyantly support a human body to a practical minimum.

Further, difficulty has been encountered in moving the patient to and from such water beds. This has been due to the relatively high and rigid side walls of the tanks previously required. Thus, it is another object of this invention to form this flotation apparatus of springy or yieldable material so as to reduce or eliminate the inconvenience to the patient as he is moved to and from the bed.

It is another object of this invention to allow the patient to float on a level with the top of the mattress, thereby reducing or eliminating the inconvenience to the patient as he is moved to and from his bed.

This invention has been embodied in a mattress adapted to be placed on the usual hospital bed. This is advantageous as it facilitates the performance of the routine aspects of nursing care, since the patient is on this water mattress and on the hospital bed at the same time, because the entire bed may be adjusted up or down in the usual manner, and other items, such as overhead trapeze bars, associated with some hospital beds, will still be available to the patient.

The water mattress comprises a base or support defining a hollow space open at the top and on the bottom generally shaped to conform to the general shape of a human body. On this base is placed a bag formed from a flexible material which will tend to follow the contour of the base. The bag is partially filled with water, or it may be filled with some other suitable fluid, but because of the contoured shape of the base, the volume of water required is that amount necessary to provide a sufficient liquid film, of practical size, between the upper bag sheet and the lower bag sheet to float the patient. With the hollowed space not much greater than the volume displaced by the floating patient, relatively little volume of water is necessary to float the patient. Thus, in the water mattress of this invention, the volume and weight of water has been drastically reduced compared to the prior art water beds, and in fact may be less than the weight of the floating patient.

In addition, the use of the fluid filled bag allows the patient to roll out of the mattress with no loss of fluid from the device. The patient, floating on a level with the top of the mattress, depresses the springy and yieldable sides of the mattress. Thus he is not exposed to any hard and unyielding surface or walls on leaving or coming on to the mattress.

This invention has also been incorporated in a seat for a patient, since many patients are confined to a seating position for long periods of time and often develop sores on their buttocks and thighs. The seat comprises a base defining a hollow space open at the top and on the bottom and generally shaped to conform to the general shape of the buttocks and thighs. A bag formed from a flexible material which will tend to follow the contour of the base is placed on the base. However, instead of partially filling this bag with water, this bag is partially filled with a liquid having a specific gravity greater than that of water, to reduce to a practical amount the depth to which the patient, in a sitting position, will sink in the liquid before he floats.

That is, due to the substantially less surface area over which the weight of the patient is distributed, when he is in a sitting position as compared to a supine position, if water were used in the seat, the patient might have to sink in up to his chest, before sufficient liquid had been displaced to create a buoyant force to float him.

The foregoing and other objects of the invention, and the best mode in which I have contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

In the drawings,

FIG. 1 is a perspective view of the water mattress illustrating the complete base, but cutting away the bag and the overlying blanket for purpose of illustration, a bed with which the mattress may be used being shown in dot-dash lines;

FIG. 2 is a longitudinal, sectional view of the mattress shown in FIG. 1 but at a larger scale, illustrating the bed and a patient in dot-dash lines;

FIG. 3 is a top view of the mattress shown in FIGS. 1 and 2 but omitting the blanket and cutting away the bag to show a portion of the base and drawn at approximately the same scale as FIG. 2;

FIGS. 4, 5, 6, and 7 are sectional views taken along the lines 4--4, 5--5, 6--6 and 7--7 in FIG. 3;

FIG. 8 is a perspective view of a seat incorporating this invention, the bag and blanket being cut away for purpose of illustration;

FIG. 9 is a sectional view taken along the lines 9--9 in FIGS. 8 and 10, but drawn at a larger scale than FIG. 8;

FIG. 10 is a sectional view taken along the line 10--10 in FIG. 9 and drawn at approximately the same scale as FIG. 9;

FIG. 11 is a perspective view of a modified seat, the bag, blanket, and the base being cut away for purpose of illustration;

FIGS. 12 and 13 are sectional views taken along the lines 12--12 and 13--13 in FIG. 11; and

FIG. 14 is a sectional view of a modified mattress, generally similar to FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, and in particular to FIG. 1, a mattress 10 or cushioning structure is illustrated, referred to hereinafter for convenience of designation, as a water mattress, comprising a support or base 12 and a bladder or bag 14 placed upon the base 12. The water mattress 10 is shown placed on a bed 16, the latter being shown diagrammatically in FIGS. 1 and 3 as it forms no part of this invention. However, it will be understood that the water mattress 10 of this invention may be placed on the usual hospital bed, on an ordinary home bed, or another desirable place.

The base 12 comprises a generally rectangular block having on its upper side a hollow cavity or space 18 open at the top and defined at the bottom by a contoured, i.e., an irregular, generally concave, surface 22, generally shaped to conform to the general shape of a human body, as shown. Thus, the space 18 has an irregular depth and width conforming generally to the human body.

The space 18 comprises (viewed from right to left in FIGS. 2 and 3) a first or head section (FIG. 4) tapering down from the upper surface 20 of the base 12 to a second or trunk section (FIG. 5) of greatest depth, a third or thigh section (FIG. 6) tapering up to a fourth or shin section, and a fifth or foot section (FIG. 7) which tapers up to the upper surface 20. Each section is made wide enough to comfortably accommodate the patient.

The bag 14 comprises two, generally rectangular, sheets 26 and 28 of flexible material, preferably a thermosetting, plastic material such as a fluid-impermeable polyvinyl. The peripheral, abutting edge margins 30 (FIG. 3) of the sheets 26 and 28 are bonded to each other to define the interior cavity 32 of the bag 14 which is thus closed except for one corner 34 of the bag where it has been cut diagonally, after bonding of the margins 30, to provide an opening to permit access into and egress out of the bag for the fluid 36 which is normally inside the bag 14 when the mattress is in use for its intended flotation purpose.

The lower sheet 26 is preferably large enough to closely follow the contour of the irregular surface 22 and to lay upon it and the top surface 20 of the base 12. The upper sheet 28 is large enough to overlie the top surface 22 but in addition is large enough to remain slack and flaccid so that no strain is placed upon it, but rather the weight of the patient is transferred to the fluid, the sheet 28 preventing contact by the patient with the fluid and helping to contain the fluid.

After the bag 14 has been partially filled with a suitable amount of fluid, the opening at the corner 34 is closed by a suitable clamp 40 and the bag is placed on the base 12, or it may be first placed on the base and then filled.

If the bag 14 is loosely placed on the base 12 the peripheral edge portions of the bag will not lay horizontally as shown in FIGS. 2 and 5, for example, but rather tend to flare upwardly following the curvature of the space 18, as shown by the dotted lines designated 41 in FIG. 5, as an example. When the bag 14 is merely placed on the base 12 there is the advantage that it can be filled and emptied remotely of the base 12.

At other times it may be desired to have the peripheral edge portions of the bag 14 lie substantially horizontally, as shown in FIGS. 2 and 5, for example, as such an arrangement tends to improve the appearance of the mattress. In this event, the lower, peripheral, marginal surface of the lower sheet is cemented to the upper surface 20 of the base 12 by a suitable cement, except in the immediate vicinity of the corner 34, so that the clamp may still be used there to close the opening at the corner 34.

Preferably the fluid placed within the bag 14 is water, since it is readily available, a deformable, yieldable, but weight supporting substance which can be molded about the patient to provide a large surface over which his weight is distributed. If water is used, the bag 14 may be filled when the mattress is needed and emptied when no longer needed, or the water may be changed, should it become stagnant and odorous.

Further, by adding to the water a suitable additive, depending on the material from which the bag is made, such as copper sulfate for a polyvinyl sheet material, or by substituting for the water in the bag a liquid such as sodium chloride solution, for example, a solution in which the sodium chloride is 5 percent, by weight, of the solution, which would have a specific gravity slightly greater than one and which would be compatible with the sheet material of the bag. This solution would tend to retard the growth of microorganisms. With such a combination, the bag may be completely sealed along its entire periphery after the liquid has been placed within it and the corner opening and clamp omitted.

Assuming water as the buoying medium, an average, adult person will float in a supine position when about two-thirds of his body sinks below the surface of the water.

The space 18 is made deep enough to accept the lower two-thirds of a body when in the supine position and, in addition, to accept the bag 14 with the practical, minimum amount of water necessary to create a film, or partial annulus, under and partially around the body, as illustrated. Theoretically only a very thin film of water would be needed, but as a practical matter enough water is preferred to that ordinary movement of the patient while on the mattress can take place without the patient frequently displacing all the water from a localized area of the bag. Thus, about two-thirds of the patient's body is below the plane of the surface 20 and one-third above it, FIG. 2. Also, usually the upper level of the water will be about even with the surface 20. If the water level rises above the plane of the surface 20, it will not spill over as the bag is closed and sealed at its margins.

To accommodate adults it has been found that a practical amount of water is about 180 to 225 pounds. The rectangular base 12 is made about 7 feet long, 3 feet wide and 1 foot thick. The deepest section of the space 18 is made about 10 inches deep, the other sections being made proportionately less deep, the length of the space 18 being about 6 feet and 6 inches and the width being tapered from a maximum width at the shoulder section to lesser widths at the foot and head sections, as generally shown in FIG. 3.

The water in the bag becomes distributed, generally as shown in FIGS. 2 and 4 to 7, i.e., molds about the patients under the pressure of the patient's body, and will rise to the plane of the surface 20, but if it rises above this plane, no spillage will take place since the bag is closed as previously noted.

As shown by the undulation of the upper sheet 28 in FIG. 2 and the folds therein, as at 44 in FIG. 5, for example, the upper sheet 28 is large enough to remain flaccid after the patient is placed on the bag 14. That is, the upper sheet 28 does not become stressed substantially by the weight of the patent, the patient's weight being supported by the liquid.

In using the water mattress it is desirable to place a blanket 46, and preferably two wool blankets, upon the bag 14, to thermally insulate the patient from the bag 14.

Preferably the base 12 is made of foam material, i.e., and expanded cellular material. One such material is a latex foam but a polyurethane or other types of plastic material could also be used. The foam rubber preferred is of medium density, i.e., soft and springy enough for comfort should the patient bear directly upon it, but hard enough so that the sides of the base will not bulge out due to the weight of the water and of the patient, and is similar to that used in mattresses for ordinary beds. That is, the sides of the base must be strong enough to resist the pressure due to the weight of the water and the patient without substantial deformation. Thus, if in placing the patient on the mattress or in removing him therefrom, he should strike the side walls of the base or the margins of the bag on the surface 20, he will strike a relatively soft or springy surface which should normally cause no discomfort.

Likewise, if in moving about on the mattress, the patient should "strike bottom," i.e., the water becomes fully or substantially displaced from a localized portion of the bag under the patient and the patient's weight is transferred to the base, for instance, as might happen if he sits up at meal time, a relatively soft and springy support will be provided by the base 12 at this time, and the loose sheet 28 moves down freely under the patient's weight which now is concentrated in a smaller surface area.

Since the interior of the bag 12 is only partially filled with water, when the patient is not lying on the bag 12 the water tends to collect at the lowest parts of the bag.

It will be understood, that if the feature of a movable bag is not desired, the lower sheet 26 could be replaced by a coating or lining of the surface 22 by a waterproofing material. In this instance, the peripheral edge portion of the upper sheet 28 would be secured, such as by a suitable cement, to the corresponding portion of the surface 20. All or a part of the sheet 28 which normally lies above the surface 20 could be so secured, but if only a peripheral part of the sheet 28 is cemented to the corresponding part of the surface, as generally indicated by the portion designated 30 in FIG. 3, the portion of the sheet 28 inwardly thereof, with the corresponding, and waterproofed, part of the base 12, would advantageously form a pocket to receive any water which would tend to rise above the surface 20.

Further, to reduce the volume of the fluid required to float the patient, a fluid having a specific gravity greater than one could be used in the removable bag or in the mattress without the removable bag. In such case, a fluid with a specific gravity of between one and three is preferred.

It will be noted that with the described and illustrated mattress construction, the patient may be easily rolled onto or out of the mattress without the need for lifting him over the high side walls of some previous water tanks, and that the pliant tapering surfaces (forming the upper parts of the surface 22) help in rolling him onto and out of the mattress.

Referring to FIGS. 8 through 12, inclusive, this invention is shown incorporated in seats. FIG. 8 illustrates a seat 60 comprising a shell or base 62 and a bag 64.

The base 62 is formed by a lower section 63 and a back support 65. The lower portion of the back support 65 is formed with a tongue cemented in a groove in the lower section 63.

The lower section 63 is formed with a space or concavity 70 generally large enough to receive the patient's buttocks and the upper part of his thighs.

The base 62 is lined with a flexible, lower sheet 71, the sheet 71 which may or may not be cemented thereto, as shown in the drawings, so as to leakproof the upper and left surfaces, respectively, of the lower section 63 and the back support 65 and defining with an upper sheet 75 a bag-like structure 79. The sheet 71 is shaped to fit and cover the part of the lower section defining the cavity 70. Also, a part of the sheet 71, rests upon a peripheral lip 74, comprising a front lip 72 and side lips 73, which with the lower part of the back support bounds the cavity 70. The upper part of the sheet 71 is draped over the upper part of the back support, as shown. The lip 74 has a substantial width, as shown, and the sheet 71 extends over the lip and is cemented to it, as shown.

A liquid suspension having a specific gravity greater than water and preferably about 2.7 to 3.3 is then placed on the part of the sheet lining the cavity 70. The suspension preferred is made by mixing 25 pounds of finely particalized lead carbonate with 12 pounds of high viscosity motor oil (Mobil Oil Compound GG) which together have a volume of about one-fifth of a cubic foot and a weight of about 185 pounds per cubic foot or a specific gravity of about 2.9, since water has a specific weight of 62.4 pounds per cubic foot, as is known. This specific gravity range gives the required buoyant force to float the patient in the sitting position with a small volume of fluid, yet permits the maximum practical surface area of the buttocks and thighs to support the body, thereby minimizing the weight per unit area.

The flexible sheet 75 is then placed over the sheet 71 and the suspension, and the sheet 75 is bonded to the sheet 71 along the peripheral margins 76, i.e., along all four sides of the sheets. The sheet 75, however, is large enough to lie loosely or flaccidly upon the suspension so that when the patient sits on it there will be plenty of excess material available, as indicated by the folds 77, FIG. 9, to allow the patient and the upper sheet 75 to sink into the cavity 70 until he floats, See FIGS. 9 and 10, at which time his weight is distributed over the maximum available surface area of his buttocks and thighs, without straining the sheet 75.

As in the previous embodiment, (latex) foam rubber material of medium density and firmness is preferred for the base 62. For the sheets 71 and 75, thermoplastic polyvinyl sheets are also preferred. With these materials, the sheet 71 may be secured to the base 62 by a suitable latex cement and the sheets may be heat bonded to each other at the margins 76.

Also, as mentioned in the previous embodiment, one or two thicknesses of blankets, preferably wool blankets, will minimize the heat loss from the patient to the liquid.

If desired, a tube 81 may be inserted through the lower section into the interior space between the two sheets, as shown in FIG. 9, to fill or empty the space, the tube 81 being screw-capped at its lower end to prevent escape of the liquid.

Also, the seat may be placed on a rigid frame 84, shown in dot-dash lines, since it is not part of this invention, if desired, or on any suitable support.

From the foregoing, it is seen that the front lip 72 provides a comfortable support for the shins, since the lower section is made of springy material of medium firmness. While not so shown in FIG. 10, the front lip 72 will be depressed slightly by the weight of the shins. Likewise, the side lips 73 will yield and provide a comfortable support should the patient, in getting on or off the seat, accidentally sit on them.

The embodiment illustrated by FIGS. 11 to 13 is similar to that shown by FIGS. 8 to 10, but here the liquid is contained in a removable bag 90 received in a cavity 91 formed in a one-piece base 92.

The base 92 has a lip 93 bounding the front and sides of the cavity 91 and a back support 94, all of which are formed integral.

Within the cavity 91 is placed the bag 90 made from flexible sheet material, the bag 90 containing within it a liquid 95 whose specific gravity is sufficiently high so that the patient, when placed in a seating position on the bag, will be buoyed upon sinking into the bag a short distance, preferably no more than about 6 inches.

While embodiments have been constructed of this invention by hollowing out rectangular blocks of the foam rubber to form the base 12 of the water, for instance, it is seen that such bases could be molded in a suitable mold.

FIG. 14 illustrates an embodiment of this invention in which the base 100 is molded of a stiff plastic to the general shape heretofore discussed for the base of a water mattress, except that it is hollow, as at 102 and has a foam rubber shoulder 103. The base 100 is provided with integral feet to be laced on the mattress or frame of an ordinary hospital or home bed. A bag 104, partially filled with water, as heretofore discussed, is placed in the cavity 106 of the base and covered by a blanket 108.

In the drawings, the thickness of the various sheets has been exaggerated relative to the other parts shown and the blanket has been shown away from the sides of the base for clarity of illustration. Polyvinyl sheets of about 0.048 inches in thickness were satisfactorily used to construct embodiments of this invention.

It is seen that both the mattress and the seat have some utility without the fluids in them, in that they can be used for their respective purposes, to comfortably rest and sit on, with the bag in place, should the fluid escape accidentally, or even without the bag being in place.

It will be readily seen that both the mattress and the fluid seat may be made in various sizes for adults and children.

Also, while specific materials have been mentioned, it is seen that other materials may also be used without departing from the scope of this invention.

From the foregoing it is seen that when a patient is placed on the mattress or the seat, high pressure areas are virtually eliminated, and as the body sinks into the surface of the bag, displacing some of the fluid, additional body surface bears the person's weight, decreasing the weight per unit area to a level below that at which sores will usually develop or minimizing them.

Claims

Having described this invention, what is claimed is:

1. A therapeutic body support structure comprising: a base of resiliently yieldable cellular material having a cavity formed in the upper surface thereof, said cavity being contoured in cross section generally to the shape of at least a portion of the human body receivable in the cavity, a bag overlying the upper surface of said base and providing a cover therefor, said bag comprising upper and lower sheets of fluid-impermeable material, said lower sheet having an area sufficient to cover the surface of said cavity and having the periphery thereof bonded to said upper sheet, said upper sheet having an area greater than the upper surface of said base to provide a flaccid cover for said cavity and the remaining upper surface of said base whereby the upper sheet is deformable into said cavity without substantial stretching under the weight of the human body, and a quantity of liquid disposed in said bag in said cavity, said liquid having a volume less than the volume of said bag, said base resisting substantial deformation under the weight of the liquid and the weight of the human body resting on said base whereby the liquid and the upper sheet of said bag are caused to mold about and provide floating support for the portion of the human body in the cavity, said base being resiliently and yieldably deformable when contacted by the human body being placed on or removed from said structure, and said bag preventing loss of said liquid when said base is so deformed.