Description:
CROSS REFERENCES TO RELATED APPLICATIONS
Co-pending application in the name of Eric A. Viesturs, Ser. No. 136,043 filed Apr. 21, 1971 and entitled "Fluid Mattress."
BACKGROUND
This invention relates generally to water mattresses, and more particularly to a water flotation mattress of the type intended for hospitals and the like, to be placed over the conventional mattress of a bed for the purpose of providing added comfort to a bed patient and to prevent decubitus ulcers or bed sores. In the past various types of water mattresses, flotation devices and systems have been proposed and produced. For domestic use there are water mattresses intended to be filled with large volumes of water and in many instances intended to replace the conventional mattress in a bedstead. These water mattresses in most cases required special supporting frames, and due to their large size and weight imposed an additional burden on the room structure whereby care had to be exercised to avoid sagging floors and overloaded flooring supports. Such mattresses were wholly unsuitable for hospital use due to their large size and weight, and due to the lack of control over a patient's movements. Mattresses of this kind moreover were unsuitable for use with hospital type beds, which universally employ adjustable spring or support structures that enable patients to be placed in partially reclining or partially sitting positions, etc.
A serious drawback to confinement in bed, even in hospitals, is the fact that bed sores or decubitus ulcers often develop, these becoming especially painful and detrimental to the comfort of the patient. In treating such bed sores, complicated water flotation systems have been developed. These systems enabled bed sores to be successfully treated and healed but the procedures involved expensive equipment which was not readily available to the average patient. While efforts have been made to develop simpler flotation systems in the form of water mattresses, these have not been especially successful for the reason that they were especially heavy and cumbersome, involved considerable time in filling and emptying, and were not effective where patients desired to be placed in semi-reclining or semi-sitting positions. Thus, universal acceptance and use of water filled flotation mattresses has not occurred due to the drawbacks mentioned.
SUMMARY
The above disadvantages of prior water flotation systems and particularly water flotation mattresses are obviated by the present invention, which has for its main object the provision of a novel and improved flotation mattress which achieves the maximum flotation effect with a minimum amount of water, being thus especially light in weight as compared with other mattresses, and retaining its effective flotation or distributed supporting action even though the patient lies on one side or the other, or is placed in a semi-reclining or sitting position. A related object of the invention is to provide an improved water flotation mattress as above set forth, which is especially sturdy and failure-resistant in its construction whereby there is no likelihood of leakage of water or collapse.
These objects are accomplished by the provision of a water flotation mattress having a novel system of internal tie strips, said mattress consisting of a pair of thin, resilient and flexible synthetic plastic upper and lower sheets which are generally in the form of a quadrilateral. The sheets are arranged in superposed relation and have their peripheral portions respectively joined to form a flat, closed and watertight bag. The bag has a stoppered filling opening, and is provided with a plurality of elongate resilient and flexible plastic tie strips which join together the upper and lower sheets in spaced apart relation, the tie strips being gnerally parallel to each other and parallel to the opposite side or marginal portions of the mattress. Those tie strips which extend closely adjacent the side edges of the bag are narrower than tie strips which are disposed in central portions of the bag. Thus, the marginal side portions of the filled bag have a lesser thickness, and carry less water than the central portions whereby there results an advantageous decrease in the overall weight of the mattress. All of the tie strips are preferably disposed in parallel rows, and the strips of the centrally disposed rows are preferably shorter than the strips of the rows adjoining the side edges of the bag or mattress. With the above construction there is not only achieved a lesser overall weight of the mattress, but in addition a reliable flotation action is maintained at all times whereby the patient's body is fully supported over large areas even when the patient is sitting or semi-reclining.
A feature of the invention resides in the provision of an improved water flotation mattress which can be readily controlled as to its temperature, and wherein an easy and convenient check can be had of the water and mattress temperature at any time.
Another feature of the invention resides in the ease of quickly filling and emptying the mattress, and in the provision of an improved stoppered filling opening embodying a pull tab whereby the operation of the stopper is facilitated.
In the accompanying drawings illustrating one embodiment of the invention:
FIG. 1 is a top plan view of a lightweight water flotation mattress as provided by the invention.
FIG. 2 is a transverse section taken on the line 2--2 of FIG. 1.
FIG. 3 is a top plan view of one of the shorter tie strips such as are employed in center portions of the mattress.
FIG. 4 is a top plan view of one of the longer and narrower tie strips as employed inside marginal portions of the mattress, and
FIG. 5 is a fragmentary section taken on the line 5--5 of FIG. 1.
As shown, the flotation mattress of the invention comprises a pair of thin, resilient and flexible synthetic plastic upper and lower sheets 10, 12 respectively, such sheets having a generally quadrilateral configuration and being arranged in superposed relation with their peripheral portions, 14, 16, 18 and 20 respectively joined so as to form a flat, closed and watertight bag. The bag thus formed is dimensioned to have a length which is less than a conventional mattress by approximately the pillow area, thereby appreciably reducing the amount of water which it holds. The sheets 10, 12 may be joined for this purpose by an electronic heat sealing or welding procedure. I have found that they can be advantageously constituted of polyvinyl chloride having a thickness of approximately 0.022 inches. Preferably the polyvinyl chloride material is formulated with an antiseptic additive such as an agent which has antibacterial properties.
Referring to FIG. 1 the upper sheet 10 is provided with a stoppered filling opening 22 by which the bag can be filled with water and emptied, using a conventional garden hose or equivalent means.
By the present invention there is provided a plurality of elongate, resilient and flexible plastic tie strips in said bag and located intermediate the longitudinal side edges of the bag, said strips joining together the upper and lower sheets 10, 12 in spaced apart relation. These tie strips, in the illustrated embodiment of the invention, are of two types -- a short relatively wide tie strip 26 as illustrated in FIG. 3 and a relatively longer, relatively narrow tie strip 28 as illustrated in FIG. 4.
Referring to FIGS. 1 and 2, all of the tie strips are arranged in spaced relation to each other and are disposed in parallel rows, said rows extending between the head and foot portions 18, 20 of the bag as shown. Two rows of the long tie strips 28 extend closely adjacent each of the elongate or side marginal or longitudinal portions of the mattress, and the central portions of the mattress are provided with rows of the shorter, wider tie strips 26. As seen in FIG. 1, eight of the long, narrower tie strips can be employed in the mattress, and twelve of the shorter and wider tie strips also employed, to provide an effective control of the water which the bag contains and to prevent undesired excessive bulging. The strips 26, 28 when properly utilized establish a desirable controlled spacing between the upper and lower sheets 10, 12.
According to the invention, with the arrangement illustrated the wider tie strips 26 provide for a greater thickness at central portions of the mattress because these portions can hold a greater amount of water. The narrower tie strips 28 on the other hand provide a lesser spacing between the upper and lower sheets 10, 12 at the marginal or side portions of the mattress whereby these portions will contain a lesser amount of water.
The width, shape and location of tie strips 26, 28 are important for proper functioning of my lightweight water flotation mattress. In working with flotation mattresses I have discovered that for best results a number of tie strips of lower height and longer length should be placed along both sides of the mattress. Somewhat wider strips, which are much shorter and larger in number should be positioned in parallel directions in the central area approximately where the patient will be resting. I have also found that best results ensued by trapping the water in the side or so-called "no-load" areas with tie strips of approximately 2 inch width, placed approximately 3 inches apart. The tie strips in the center or load areas can be approximately 3 inches high, placed approximately 5 inches apart and these can even be entirely eliminated in areas directly under the patient's body.
When properly filled with flotation mattress as described herein will provide for the patient's body to be relatively free floating, permitting the body to sink into the mattress only to a controlled depth so that the more protruding bone prominences in the shoulder and hip areas will not touch the bottom sheet or the regular under mattress. Some tie strips in the load area are necessary because, when the patient changes his position certain areas will suddenly be released of pressure. Water tends to rush into these released areas, and other portions of the patient's body could then suddenly sink down and hit bottom. The purpose of the tie strips is thus to control the water displacement and distribution. This is especially important when the head end of the bed is raised and part of the mattress behind the patient's back is partially upright. The tie strip system as described does not permit all of the water to rush down into the horizontal section, but instead much is still held in the upright portions, providing sufficient rest and cushioning for the patient's back.
I have found that the side or marginal portions of the mattress which normally constitute those areas on which the arms of a patient rest, do not require the large amount of water required in the central portions, for the reason that they experience a lesser weight. Accordingly, by making the mattress so that it contains less water in its sides there is achieved a substantial reduction in the overall weight, which is of considerable advantage in enabling the mattress to be conveniently handled.
For example, a mattress which has a size of 36 inches wide by 64 inches long will contain a total weight of water of from 120 to 160 pounds where the spacing of sheets between the marginal portions is approximately 2 inches and the spacing of sheets at the central portions is approximately 4 inches. This filled weight of the mattress is well within the maximum load limits of the modern electric hospital bed. Moreover, such weight is not prohibitive in enabling nurses or attendants to handle a filled mattress, as when making up a bed, attending to the patient, etc.
The tie strips 26, 28 are electronically heat welded or sealed to the upper and lower sheets 10, 12, the weld lines for the long strips being indicated at 32 and the weld lines for the short strips being indicated at 34. The distance between the outer tie strips 28 can advantageously be approximately 3 inches, and the distance between the inner tie strips 26 can be approximately 4 to 6 inches. In each instance the welding lines terminate in enlarged end areas indicated by the numerals 38, 40 respectively for the long and short strips, such enlarged areas being termed "teardrop" areas. A greater strength is thus had for the fused or welded portions of the bag.
Additionally, in accordance with the invention, at the ends of the elongate tie strips 26, 28 wide notches 42, 44 are provided whereby stresses on the enlarged end welds or teardrop areas are minimized. The notches 42, 44 each define two rounded projecting ears at the corners of the tie strips, each of the ears being joined by a smooth and unbroken edge (the edges at the base of the corresponding notches 42, 44). This minimizes high local tearing stresses which would normally occur at the ends of such tie strips. The likelihood of the strips becoming torn under conditions of excessive weight applied to the bag is thus greatly minimized. Instead, the stresses are partially distributed along those heat sealed or fused areas which are removed from the teardrop ends. With such construction there is had a reliable securement of the tie strips to the upper and lower sheets, with the least likelihood of failure of the bag and leakage of water. Due to the configuration and lesser thickness of the tie strips, these will fail before the bag tears if excessive forces beyond those occurring in normal use are encountered. Thus no water leakage is likely to occur under any circumstance of excessive weight.
The areas of the strips between or intermediate the ends thereof can handle extreme stress caused by water pressure, weight of the patient, etc., for the reason that the stress is distributed over a long area or length.
I have found that, by the provision of the shorter tie strips in the central portions of the mattress or bag there is had a greater flexibility and also a better distribution of the contained water, to the end that no collapse of the mattress will occur normally if the hospital bed is operated to place the patient in a semi-reclining or partially sitting position. The water is always confined mostly in the central portions, and becomes distributed in a manner controlled by the tie strips, so that no excessive bulging of the bag can occur at any one point. As a consequence, a relatively uniform distribution of the water is had for all conditions of use, preserving and maintaining the flotation action which is so desirable. When a bag as above constructed is filled to a thickness of 3 to 4 inches and is supporting a patient, the pliable top sheet will adjust itself to the contours of the body, and the special tie strip arrangement will prevent the patient's body from receiving support from the bottom mattress sheet. Without the tie strips, the bag would bulge around the patient to a thickness of 6 or 7 inches.
As already stated above, the flotation mattress is intended to be placed over the conventional mattress of a bed, such conventional mattress being indicated by the numeral 48 in FIG. 2.
In accordance with the invention, the upper mattress sheet 10 is provided with a flat, transparent pocket 50 adapted to contain a rigid transparent plastic flat case 52 which carries a thermometer 54. The thermometer can thus be read while carried in the case 52 and pocket 50, thereby indicating the temperature of the plastic upper sheet and giving a relatively accurate indication of the water temperature of the mattress.
For the purpose of facilitating the removal and application of the stopper 60 to the opening 22 I provide a pair of pull tabs 56 constituted of flexible plastic material, with finger openings 58, said tabs being secured to the upper sheet 10 at the opening 22 and enabling the operator to hold the upper sheet securely while applying or removing the stopper. The fitting for the stopper 60 will receive the standard coupling connection of an ordinary garden hose. By virtue of this, the mattress can be easily and quickly filled and emptied while on location, with the least effort, waste of time and water spillage.
It will now be seen from the foregoing that I have provided a novel and improved water flotation mattress of extremely simple construction, which is rugged and durable and not likely to suffer failure, said mattress being especially arranged to minimize the weight of water which it contains whereby it falls within the realm of practical hospital accessories. The mattress is especially useful in preventing and/or treating decubitus ulcers or bed sores suffered by patients, and provides a comfortable, water flotation type support which eliminates high pressure areas and instead provides minimum body supporting pressures at a level where they are not dangerous or irritating.
For the purpose of anchoring the flotation mattress, a thin resilient and flexible plastic extension sheet 64 is provided, said sheet being attached to the head marginal portion 18 of the bag and being adapted to underlie the pillows and to be anchored to the head portion of the hospital bed whereby the mattress will be securely positioned thereon.
It can now be understood that the present invention provides a new, inexpensive, and improved light weight water flotation mattress which can be readily used on top of a regular mattress, and which need be filled with water to a weight of only 140 to 160 pounds, depending on the weight of the patient. It can be filled and made ready for use in less than 10 minutes, has provision for monitoring water temperature, can be easily anchored to the head of the bed so that the mattress stays put and does not slide down to the foot end even when the head of the bed (with the patient) is raised or lowered for his comfort. Although the head of the bed is placed in a raised position the mattress will still contain enough water in the upright section to provide adequate support for the patient's back. The mattress can be made of thermoplastic material such as polyvinyl chloride, making it possible to include in its formulation anti-bacteriastats such as are necessary to prevent buildup of algae inside and to maintain sanitary surfaces on the outside.
The lightweight water flotation mattress according to my invention when not in use weighs only approximately 4 pounds and can be easily folded and stored in a small box on a shelf. The filling with water is accomplished by a simple hose system which permits a very fast water flow. By use of a combination of hose lengths, using sections of regular garden hose, the flotation mattress can be filled directly when positioned on the patient's bed thus making it unnecessary to fill it in a special maintenance room or bathroom, and then move the filled mattress to the patient's room or bedroom.
Variations and modifications are possible without departing from the spirit of the invention.