Title:
Zoned cellular cushion with fail safe inflation zones
Kind Code:
A1


Abstract:
A pattern of airflow pathways among inflatable air cells in an inflatable air cell cushion that result in discrete, isolated inflation zones that allow the optimal immersion depth and support of a seated,user when fully inflated and maintain acceptable immersion depth and support of the seated user in the event of an air leak from one of the inflation zones. The airflow pathways are operably connected to a valve wherein opening of the valve places the normally isolated inflation zones in fluid communication and closing of the valve isolates the inflation zones.



Inventors:
Graebe, Robert H. (Fort Lauderdale, FL, US)
Application Number:
11/222687
Publication Date:
03/15/2007
Filing Date:
09/09/2005
Primary Class:
Other Classes:
5/654
International Classes:
A47C27/10
View Patent Images:
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Primary Examiner:
LIU, JONATHAN
Attorney, Agent or Firm:
Sandberg Phoenix & von Gontard, PC (St. Louis, MO, US)
Claims:
1. An inflatable cellular cushion for the support of a seated user, comprising: a base having a front edge, a rear edge, a first side edge and a second side edge; an array of individual upstanding inflatable air cells on said base, said array of air cells arranged in rows and forming a supportive seating area; a plurality of air conduits, each said air conduit being in fluid communication with a separate group of said individual cells to form a first substantially rectangular centrally positioned inflation zone, a second inflation zone positioned substantially surrounding said centrally positioned inflation zone on three sides, a third inflation zone extending along one side of the second inflation zone, and a fourth inflation zone extending along an opposite side of the second inflation zone; and a valve in fluid communication with said plurality of air conduits, said valve capable of being manipulated from an open position wherein all of the recited inflation zones are in fluid communication through the valve, to a closed position wherein the recited inflation zones are out of fluid communication with each other.

2. In an inflatable cellular cushion having a base and an array of individual upstanding inflatable air cells arranged in rows across the base, a pattern of air flow pathways among the inflatable air cells, said pattern of air flow pathways creating at least two normally isolated inflation zones that maintain optimal positioning of a user seated on the cellular cushion when the inflation zones are inflated and also maintain adequate positioning of the user seated on the cellular cushion if at least one of the at least two inflation zones deflates.

3. The pattern of air flow pathways of claim 2 wherein the air flow pathways create three normally isolated inflation zones.

4. The pattern of air flow pathways of claim 2 wherein the air flow pathways create four normally isolated inflation zones.

5. An inflatable cellular cushion for the support of a seated user, comprising: a base; an array of individual inflatable air cells on said base; at least two air conduits, each of said air conduits interconnecting a separate series of individual cells forming an inflation zone of interconnected cells, each of said inflation zones being positioned on the cushion so as to provide optimal positioning and immersion of a user seated on the cellular cushion when the inflation zones are inflated and also maintain adequate positioning and immersion of the user seated on the cellular cushion if at least one of the at least two inflation zones deflates.

6. The inflatable cellular cushion of claim 5 further comprising a valve in fluid communication with said at least two air conduits, said valve capable of being manipulated from an open position wherein all of the recited inflation zones are in fluid communication through the valve to a closed position wherein the recited inflation zones are out of fluid communication with each other.

7. The inflatable cellular cushion of claim 5 wherein the inflatable air cells are molded neoprene.

8. An inflatable air cell cushion that is resistant to complete cushion failure in the event of an air leak from at least one air cell comprising: a base with an array of individual inflatable cells thereon, said array of cells being divided into at least two discrete inflation zones comprising interconnected air cells, said at least two discrete inflations zones positioned so that a supportive portion of each inflation zone is positioned under a seated user to provide positioning and support in use and so that a supportive portion of at least one inflation zone remains inflated under the seated user in the event another of said zones deflates.

9. The inflatable air cell cushion of claim 8 comprising at least three discrete inflation zones.

10. The inflatable air cell cushion of claim 8 comprising at least four discrete inflation zones.

11. An inflatable cellular cushion for the support of a seated user, comprising: a base having a front edge, a rear edge, a first side edge and a second side edge; an array of individual upstanding inflatable air cells on said base, said array of air cells arranged in rows and forming a supportive seating area; a plurality of air conduits, each said air conduit being in fluid communication with a separate group of said individual cells to form a plurality of individual inflation zones; wherein said supportive seating area comprises a pattern of said individual inflation zones that provides proper positioning and immersion of the user seated on the supportive seating surface when the inflation zones are inflated and also maintains adequate positioning and immersion of the user seated on the supportive seating area if at least one of the individual inflation zones deflates.

12. The inflatable cellular cushion of claim 11 further comprising a valve in fluid communication with said plurality of air conduits, said valve capable of being manipulated from an open position wherein all of the recited inflation zones are in fluid communication through the valve, to a closed position wherein the recited inflation zones are out of fluid communication with each other.

13. The inflatable cellular cushion of claim 11 further comprising a first substantially rectangular centrally positioned inflation zone, a second inflation zone positioned substantially surrounding said centrally positioned inflation zone on three sides, a third inflation zone extending along one side of the second inflation zone, and a fourth inflation zone extending along an opposite side of the second inflation zone.

14. The inflatable cellular cushion of claim 11 further comprising a first centrally positioned inflation zone extending from the front edge of the base to the rear edge of the base; a second inflation zone positioned on each side of the first inflation zone; a third inflation zone positioned on each side of the second inflation zone; and a fourth inflation zone positioned on each side of the third inflation zone.

15. The cushion of claim 11 wherein the array of individual inflatable cells are molded from neoprene.

16. An inflatable cellular cushion for the support of a seated user, comprising: a base; an array of individual upstanding inflatable air cells on said base, said array of air cells forming a supportive seating area; a plurality of air conduits, each said air conduit being in fluid communication with a separate group of said individual cells to form a plurality of individual inflation zones; a valve in fluid communication with said plurality of air conduits, said valve capable of being manipulated from an open position wherein all of the recited inflation zones are in fluid communication through the valve, to a closed position wherein the recited inflation zones are out of fluid communication with each other; wherein said supportive seating area comprises a pattern of said individual inflation zones that provides proper positioning and immersion of the user seated on the supportive seating surface when the inflation zones are inflated and also maintains adequate positioning and immersion of the user seated on the supportive seating area if at least one of the individual inflation zones deflates while said valve is in a closed position.

17. The inflatable air cell cushion of claim 16 comprising three air conduits and three individual inflation zones.

18. The inflatable air cell cushion of claim 16 comprising four air conduits and four individual inflation zones.

19. The inflatable air cell cushion of claim 16 wherein said valve further comprises a slide valve.

20. The inflatable air cell cushion of claim 16 wherein each quadrant of the supportive seating area comprises at least two individual inflation zones.

21. The inflatable air cell cushion of claim 16 wherein each quadrant of the supportive seating area comprises at least three individual inflation zones.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

This invention relates in general to inflatable mattresses and cushions and, more particularly, to improved air flow pathways among the inflatable cells comprising an inflatable cellular cushion, resulting in normally isolated inflation fail-safe inflation zones under vulnerable areas of a seated user's anatomy in the event there is an air leak in a cell that results in deflation of at least one other normally isolated zone.

Individuals who are confined to wheelchairs run the risk of tissue breakdown and the development of pressure sores, which are extremely dangerous and difficult to treat and cure. Typically, much of the individual's weight concentrates in the region of the ischia, that is, at the bony prominence of the buttocks, and unless frequent movement occurs, the flow of blood to the skin tissue in these regions decreases to the point that the tissue breaks down. Wheelchair cushions exist that reduce the concentration of weight in the region of the ischia, and these cushions are designed to distribute the user's weight more uniformly over a larger area of the buttocks.

Cellular cushions provide the most uniform distribution of weight and thus provide the greatest protection from the occurrence of pressure sores. These cushions have an array of closely spaced air cells that project upwardly from a common base. Within the base the air cells communicate with each other, and thus, all exist at the same internal pressure. Hence, each air cell exerts essentially the same restoring force against the buttocks, irrespective of the extent to which it is deflected. The inventor's U.S. Pat. No. 4,541,136 shows a cellular cushion currently manufactured and sold by ROHO, Inc. of Belleville, Ill., for use on wheelchairs.

A cellular cushion should provide a highly displaceable surface that tends to float the user. While this reduces the incidence of pressure sores, in rare instances it can detract from the stability one usually associates with a seating surface. Most persons confined to wheelchairs have little trouble adjusting to the decrease in stability, but for those who have skeletal deformities, particularly in the region of the pelvis and thighs, and for those who lack adequate strength in their muscles, lesser stability can be a source of anxiety. A variation of the cellular cushion addresses this problem with totally isolated zones and also with cells of varying height. By varying the volume of air between zones, for example, one can accommodate for skeletal deformities while still maintaining satisfactory protection against pressure sores. U.S. Pat. No. 4,698,864 shows zoned cellular cushion with cells of varying height designed by the present inventor. U.S. Pat. No. 5,163,196 and U.S. Pat. No. 5,502,855 disclose other zoned cellular cushions having isolated inflation zones.

The industry has seen an improvement in valves required by zoned cellular cushions. Early zoned cushions, such as those disclosed in the afore mentioned patents, employed integral channels which lead from the several zones and which are connected through an integral common manifold and associated valve. One such valve comprises a flap that is folded over to seal off the ends of the channels or opened to allow communication between the zones through a manifold contained within the flap. However, in the flap-type valve, the flap is manually folded closed and secured with a snap or the like.

Newer valves designed to be easier to manipulate and minimize air leakage are the subject matter U.S. Pat. No. 6,687,936 and U.S. Pat. No. 6,687,936, both of which are incorporated herein by reference. These valves, which can be referred to broadly as slide valves, when employed for example with a zoned cushion having a plurality of inflation zones, provide an easily manipulated valve assembly which can be used to allow fluid communication between two or more zones or can be used to isolate the zones. The valve also provides structure for attaching the valve to the cushion to help prevent dislocation and leakage.

The valve, in general, includes a casing having an internal bore and a plurality of openings along the length of the casing that open into the bore. The openings are connected to the individual inflation zones via tubing or the like to place the bore of the casing in communication with the inflation zones. The valve also includes a movable slide seated snugly within the casing bore. The slide has a longitudinal internal bore and a number of openings along its length that communicate with the slide bore. Generally the number of openings in the slide is the same as the number of openings in the valve casing. The openings are isolated by seals positioned on each side of the opening to form discrete air chambers at each opening. The slide can be manipulated to align the discrete air chambers with the casing openings so as to functionally align the slide openings with the casing openings to allow the inflation zones to communicate and the air to flow to and from the various inflation zones through the valve slide bore. Correspondingly, the slide can be manipulated to move the slide openings and the casing openings out of alignment, thereby sealing off the inflation zones.

Heretofore, these novel slide valves have been employed with zoned cellular cushions comprising four inflation zones, generally the four quadrants of the cushion. As can be appreciated by one skilled in the art, a user optimally positioned on such a cushion has support under the entire buttocks, particularly the vulnerable ischial area. However, if the quadrants are sealed off or isolated, and a leak develops in a quadrant, the entire quadrant can deflate and bottom out. There is a corresponding change in immersion depth at the entire quadrant of the cushion and the seated user's pelvic position will change from the initial position. A substantial area of the user's buttocks also could be vulnerable to pressure sores. It would be advantageous, therefore, to have air flow patterns in the cushion that create inflation zones that offer support and stability to the user, but also create discrete, isolated inflation zones under the most vulnerable area of the buttocks. In the event one zone deflates, there still is sufficient support under the vulnerable areas to maintain user stability and to prevent complete bottoming-out.

SUMMARY OF THE INVENTION

In an inflatable cellular cushion having a base and an array of individual upstanding inflatable air cells, a pattern of air flow pathways among the inflatable air cells that create a pattern of normally isolated inflation zones that maintain optimal positioning and support of a user seated on the cellular cushion when the inflation zones are inflated and also maintain adequate positioning and support of the user seated on the cellular cushion if at least one of inflation zones fails and deflates.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The various aspects of the invention are achieved as set forth in the illustrative embodiments shown in the drawings, which form a part of the specification.

FIG. 1 is a top perspective view of a zoned cellular cushion;

FIG. 2 is a bottom plan view of a prior art zoned cellular cushion;

FIG. 3 is schematic of one embodiment of air passage patterns and inflation zones of the present invention;

FIG. 4 is schematic of another embodiment of air passage patterns and inflation zones of the present invention; and

FIG. 5 is schematic of another embodiment of air passage patterns and inflation zones of the present invention.

Corresponding reference numerals refer to corresponding elements of the invention throughout the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the letter C designates one exemplary embodiment of a cellular cushion which is highly flexible and is designed for use on an underlying supporting surface, such as the seat of a wheelchair, the seat of a vehicle or the seat of a conventional chair. Being cellular, when inflated, cushion C distributes the weight of its occupant generally uniformly over the entire area of the buttocks and thereby dissipates the pressures resulting from the supported weight of the ischia, that is, the bony prominence of the buttocks. It further has the capacity to position and stabilize the user. Cushion C can incorporate airflow pathways and inflation zones of the prior art, as shown in FIG. 2, or the novel airflow pathways and inflation zones of the present invention, which will be described in greater detail below.

In general, cushion C includes a base 2 and individual, inflatable air cells 4 that project upwardly from the base 2. Generally the air cells 4 are molded as a conformal having a web 5 interconnecting the cells 4. The base is comprised of the web and a backing 3. Both the backing 3 and the air cells 4 preferably can be molded or otherwise formed from a highly flexible neoprene. The cells 4 and web 5 may be formed from neoprene over a mandrel in a dipping operation as described in U.S. Pat. No. 4,541,136, which is incorporated herein by reference.

On the other hand, the air cells 4 can be molded from a highly flexible neoprene and the base 2 can be vacuum formed of the web and a backing formed from polyurethane, for example, and appropriately attached to the conformal. The cushion also can be fashioned from other materials, such as vacuum or injection or rotational molded plastic materials. An inflatable air cell cushion of any material can employ the novel features of the present invention. The base also can be a semi-flexible or rigid base without departing from the scope of the invention.

The base 2 generally is rectangular and the cells 4 are arranged on it in longitudinal and transverse rows, with each cell occupying both a longitudinal and a transverse row. It will be appreciated that although the illustrated embodiment provides for individual cells each having a configuration consisting of four fins F, the configuration of the individual cells is incidental to the invention. The present invention can be used with a cushion employing any preferred configuration of cells 4, that is, for example, cells having any number of fins or sides, cells having no fins, for example, cylindrical, cubical cells or rounded cells.

The array of cells 4 forms a supportive seating area when the cells are appropriately inflated.

In prior art cushions, such as cushion C2 in FIG. 2, the cells 4 are further arranged in zones, typically in the prior art four zones r, s, t and u. The zones r and s lie side by side at the front of the cushion C2 and the zones t and u exist side by side at the rear of the cushion A. The right zones rand u are separated from the left zones s and t along a longitudinal axis x, whereas the front zones r and s are separated from the rear zones t and u along a transverse axis y.

Within the base 2 the cells 4 of the zone r communicate with each other, so that all exist at the same general internal pressure irrespective of how far any individual cell is depressed. The same holds true with regard to the cells 4 of the zone s, the cells 4 of the zone t, and the cells 4 of the zone u. In other words, the cells 4 of zone rare normally isolated from the cells of the remaining zones s, t and u. Likewise, the cells 4 of the zone s are normally isolated as are the cells 4 of zones r, t and u and so forth. Thus, the cells 4 of each zone r, s, t and u collectively define a separate inflation zone or compartment.

A fluid conduit 6 or air passage extends from zone t toward the front of the cushion. Likewise a fluid conduit 8 extends from zone u to the front of the cushion. Two shorter conduits 10 and 12 extend from zones s and r respectively toward the front of the cushion. The conduits 6, 8, 10 and 12 all terminate near an edge of the cushion and are in fluid communication with the cushion valve 20, as will be explained below. It also will be appreciated that the various conduits can be formed in any appropriate manner without departing from the scope of the invention. For example, the conduits can be formed integrally in the base 2 when the base is molded or vacuum formed.

The prior art embodiment of FIG. 2 includes a prior art configuration of conduits. The conduits can be formed in any acceptable manner that results in access to the conduits at one location on the periphery of the cushion so that a valve can be utilized. By way of example, the conduits can be formed into the web 5 or can comprise separate tubing without departing from the scope of the invention. An air filling valve 14 is located at zone r that is opened and closed simply by turning its end. It will be appreciated, however, that the air fill valve can be located at any desirable and convenient location on the cushion.

The conduits 6, 8, 10 and 12 are operatively connected to a slide valve 20. When closed, the valve 20 isolates the cells 4 of the several zones r,s,t and u. But when opened, it interconnects the zones r, s, t, and u, so that the interiors of all the cells 4 in all zones are in communication and, therefore, all exist at the same internal pressure. The air filling valve 14 enables air to be pumped into the cells 4 of the zone in which it is located and, when the valve 20 is open, the air inflates the cells 4 of all of the zones r, s, t and u. Use of only one air-filling valve 14 insures all of the cells 4 in the zones r, s, t, and u will be at the same initial pressure, even though the volume of air in the cells or zones may vary in use.

Valve 20 is constructed according to the teachings of U.S. Pat. No. 6,687,936 or U.S. Pat. No. 6,564,410, both of which are incorporated herein by reference. In general, when valve 20 is in the open position, the respective inflation zones of the cushion are in fluid communication with each other via conduits 6, 8, 10 and 12 through the open slide valve 20. In a closed position, the ends of conduits 6, 8, 10 and 12 are sealed off and the inflation zones are isolated.

The use of a valve that allows intercommunication to initially perform the immersion calibration and then perform a posture adjustment and then can be closed for isolation of air passages allows a means to hold the selected posture and enhance overall stability of the user while enjoying the benefits of optimum shape fitting, with floatation support to facilitate blood flow. A system is considered stable if it returns to its original position/condition after a disturbing force is removed. The cushions of the present invention maintain a posture and a high degree of stability resistive forces must exist. The designs provide for as many evenly distributed resistive forces as possible especially when there is reduction in the initial number of active force elements.

In order to prepare the cushion C2 for the user, the valve 20 is opened to open the conduits 6, 8, 10 and 12 and thereby allows the conduits to be in fluid communication with the bore of the valve slide which places the four zones r, s, t and u in communication through the valve slide bore. The air-filling valve 14 is opened and air is pumped into it with a pump, which connects to the valve 14.

The air initially flows into the cells of zone r, but since the cells of the remaining zones s, t and u are in communication with the cells of zone r through the open valve, all of the cells 4 are inflated and the cells 4 reach a state of equilibrium. Enough air is pumped into the cushion C2 to exceed the requirements for supporting the user. The valve 14 then is closed and the pump removed.

Next, the over-inflated cushion C2 is placed on the supporting surface upon which it is to rest when supporting a user. The user then sits upon the cushion C2 in the location he or she expects to assume and slowly releases air from the air filling valve 14 to immerse the user. As air is released, the user's buttocks sink deeper and deeper into the array of cells 4, and they tend to envelop and assume the contour of the buttocks. Enough air is released to bring the region of the ischia to within about ½inch of the base 2. Of course, as air flows out of the cushion C2 all of the cells 4 remain at essentially the same internal pressure because they are interconnected through the open valve. When the user achieves the desired immersion, the air filling valve 14 is closed.

While immersed in the cells of the cushion C2, and the valve 20 is open, the user moves, or is moved by others, to the posture desired to be maintained for an extended period and this causes a redistribution of air amongst the cells 4 of the several zones r, s, t and u. In time, the cells 4 of the several zones r, s, t and u reach equilibrium, that is to say, the flow between the zones r, s, t and u ceases. At this time the valve slide is manipulated to a closed configuration, thereby preventing air flow through the slide bore and thus isolating the zones r, s, t, and u.

It will be appreciated by those skilled in the art that each quadrant of the prior art cushion includes only one individual zone, e.g. r,s,t and u. A user seated substantially centrally on cushion C2 would have his or her ischial area supported by a portion of each quadrant. If a leak develops in any of the four inflation zones, the entire cushion quadrant can completely deflate, resulting in a bottoming out of that section of the zoned cellular cushion. If undetected, the seated user's immersion depth is altered and the user can become destabilized. The seated user also could develop pressure sores on that area of the anatomy positioned on the deflated quadrant. The fail safe inflation zone patterns of the present invention, as will not be described in detail, can prevent such a failure.

FIG. 3 illustrates an inflatable cellular cushion, indicated generally at C3, including air flow pathways through interconnected cells that can not only create novel inflation zone patterns that can optimally immerse and position a seated user when fully inflated, but can also maintain satisfactory immersion depth and positioning in the event of an air leak from any of the isolated zones. The terms air passages, air flow passages, air flow passage patterns, air passage designs, air flow circuits and so forth are intended to broadly include that air flow between or among individual inflatable cells that create an inflation zone comprising those interconnected cells. Hence, different air flow passage patterns will result in different inflation zone patterns.

In general, cushion C3 will include a base and air cells, such as air cells 4 that project upwardly from the base and may be formed from dip-molded neoprene as described in U.S. Pat. No. 4,541,136. Other designs of cellular cushions constructed from alternative materials and molded by other molding techniques, such as vacuum molded polyvinyl chloride cellular cushions, also fall within the scope of the invention.

In any event, cushion C3 includes an air filling valve 14 and slide valve 20, which are positioned on what will be referred to for purposes of orientation as the front of the cushion. Slide valve 20 is constructed and functions as described above. Slide valve 20, as employed with cushion C3, accommodates three conduits 22, 24 and 26.

As shown, conduit 22 is in fluid communication with a series of interconnected cells. Because the cells are interconnected, there is an airflow pathway, indicated schematically at 22A, through these cells and the interconnected cells form an inflation zone a. Zone a comprises four alternating rows of interconnected cells, evenly spaced from the front of the cushion to the back of the cushion.

Conduit 24 is in fluid communication with a series of interconnected cells that comprise a normally isolated inflation zone b having an internal air flow pathway indicated schematically at 24A. Zone b comprises three alternating rows of interconnected cells from front to back of the cushion in the approximate front two-thirds of the cushion.

Conduit 26 is in fluid communication with a series of interconnected cells that comprise a normally isolated inflation zone c which has an internal airflow pathway 26A. Zone c comprises two spaced apart rows of interconnected cells, occupying the approximate back one-third of the cushion. There is one row of cells from zone a positioned between the two rows of zone c. It will be appreciated by those skilled in the art that when a user is appropriately positioned on cushion C3, the predominant portion of the user's critical ischial region will be supported by the last four or five rows of cells or the approximate rear one-third to one-half of the cushion. Hence, the predominant portion of the user's ischial area will be supported primarily by zone c and at least one row of cells from inflation zone a.

Referring to FIG. 3, it is seen that the three inflation zones a, b and c, form a contiguous support surface across the expanse of cushion C3. For use, the user is appropriately positioned on the cushion, as described above in reference to prior art cushion C. In summary, the valve 20 is opened to open conduits 22, 24 and 26 and thereby allows the conduits to be in fluid communication with the bore of the valve slide which places the four zones a, b and c in communication through the valve slide bore.

The air-filling valve 14 is opened and air is pumped into it with a pump. The air initially flows into the cells of zone b, but since the cells of the remaining zones a and c are in communication with the cells of zone b through the open valve, all of the cells 4 are inflated and the cells 4 reach a state of equilibrium. Enough air is pumped into the cushion C3 to exceed the requirements for supporting the user. The valve 14 then is closed and the pump removed.

Next, the over-inflated cushion C3 is placed on the supporting surface upon which it is to rest when supporting a user. The user then sits upon the cushion C3 in the location he or she expects to assume and slowly releases air from the air filling valve 14 to immerse the user. As air is released, the user's buttocks sink deeper and deeper into the array of cells 4, and they tend to envelop and assume the contour of the buttocks. Enough air is released to bring the region of the ischia to within about ½ inch of the base of the cushion. As air flows out of the cushion all of the cells 4 remain at essentially the same internal pressure because they are interconnected through the open valve. When the user achieves the desired immersion, the air filling valve 14 is closed.

While immersed in the cells of the cushion C3, the valve 20 is opened, the user moves, or is moved by others, to the posture desired to be maintained for an extended period and this causes a redistribution of air amongst the cells 4 of the several zones a, b and c. The cells 4 of the several zones a, b and c reach equilibrium. When the user reaches the desired posture, the valve 20 slide is closed to prevent air flow through the slide bore, thus isolating the zones a, b and C.

The inventor has determined that the configuration of zones a, b and c provide appropriate stability and support to the seated user. However, as can be appreciated, the user's buttocks are supported by at least a portion of each zone a, b and c. For example, each of the four quadrants of the cushion defined by the x and y axes contain at least two inflation zones. The rear two quadrants include all three inflation zones. Consequently, if a leak develops in an air cell, and one or more of the normally isolated zones a, b or c deflates, the seated user will be adequately supported and positioned by those zones that remain inflated to prevent destabilization and possible injury due to bottoming out. Hence, cushion C3 includes fail safe air flow patterns and fail safe inflation zones.

FIG. 4 illustrates an inflatable cellular cushion, indicated generally at C4, that includes another embodiment of novel air flow passage and inflation zone patterns that result in inflation zones that allow optimal immersion and positioning of a seated user when fully inflated, but can also maintain satisfactory immersion depth and positioning stability in the event of an air leak from any of the isolated zones. In general, cushion C4 includes a base and air cells, such as air cells 4 that project upwardly from the base. There is a slide valve 20 and inflation valve 14 at the front of the cushion. Valve 20 is in fluid communication with four air conduits, 28, 30, 32 and 34 and functions as described above.

Conduit 28 is in fluid communication with air flow pathway 28A among a series of interconnected cells that comprise an inflation zone d. Conduit 30 is in fluid communication with a series of interconnected cells forming air flow pathway 30A that forms an inflation zone e. Likewise, conduit 32 is in fluid connection with a series of interconnected air cells forming air flow pathway 32A resulting in inflation zone f. And conduit 34 is in fluid communication with a series of interconnected air cells through air flow pathway 34A that comprise inflation zone g. In this illustrated aspect of the invention, the inflation zones are arranged in a generally concentric pattern, with generally centrally positioned zone f being flanked by zone g; zone g is flanked by zone e; and zone e is flanked by zone d.

Cushion C4 is set up and inflated in a manner similar to the cushions described above so that the seated user is optimally supported and stabilized. However, it can be recognized from the arrangement of zones d, e, f and g that failure of any one zone would not result in complete bottoming out of the cushion, since an adjacent zone would provide sufficient support to prevent a catastrophic failure. For example each quadrant of cushion C4 as defined by the x and y axes contains at least three of the individual inflation zones. Hence, cushion C4 also includes a failsafe design.

Cushion C5, shown schematically in FIG. 5, is another embodiment of a cushion of the present invention employing air flow pathways that result in normally isolated discrete inflation zones that provide sufficient support and positioning of a patient even in the event of a leak, and deflation of at least one of the individual inflation zones. Cushion C5 is constructed in a manner described above and includes a base with an array of individual inflatable cells 4. Cushion C5 includes a slide valve 20 and an inflation valve 14 at the forward edge. Slide valve 20 is in fluid communication with four air conduits, these conduits are in fluid communication with air flow pathways 36, 38, 40, and 42.

Conduit 36 is in fluid communication air flow pathway 36A among a series of interconnected cells that comprise an inflation zone h. Conduit 38 is in fluid communication with a series of interconnected cells forming air flow pathway 38A that forms an inflation zone i. Likewise, conduit 40 is in fluid connection with a series of interconnected air cells forming air flow pathway 40A resulting in inflation zone j. And conduit 42 is in fluid communication with a series of interconnected air cells through air flow pathway 42A that comprise inflation zone k.

In this illustrated aspect of the invention, the inflation zone j is rectangular in configuration and located generally in the center of the cushion. Zone i is positioned on both sides of and behind zone j, substantially surrounding zone j on three sides. Zone h extends along the length of one side and approximately half of the rear edge of the cushion. Zone k extends along the length of the opposite side and the other half of the rear edge of the cushion. As can be appreciated from FIG. 5, even if zone j would fail, zones h, i and k would appropriately and safely support a seated user, particularly the critical ischial area. Likewise, if either zone h, i or k failed, the seated user would be safely and appropriately supported by the remaining inflated zones.

Cushion C5 is set up and inflated in a manner similar to the cushions described above so as to optimally support and stabilize the seated user. Each quadrant of cushion C5 as defined by the x and y axes contains at least three of the individual inflation zones. Hence, Cushion C5 also includes a failsafe design. In the event of failure, the remaining inflated zones provide adequate support and stabilization for the user. Cushion C5 has particular advantages in that if zone h or k fail, the other of the zones still would provide some support across the rear edge of the cushion so that the user remain would remain positionally stable front to back, while zone i helps maintain lateral support and stability.

It will be appreciated that the cushions heretofore described provide inflation zone patterns that provide optimal immersion and positioning when fully inflated, while also providing acceptable immersion and positioning if there is deflation of a zone. These inflation zone patterns are intended to be illustrative of the broader invention, and other inflation zone patterns may also provide such immersion and support, without departing from the scope of the invention. Therefore, the embodiments shown should be considered as illustrative of the broader aspects of the invention and should not be considered as limiting the scope of the appended claims.





 
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