Cushion for seating

A hybrid seating cushion made up of a cushion base and a cushion insert. The cushion base has a seating surface in which a void in or extending through the cushion base is formed. A cushion insert such as an air bladder or fluid sack is positioned within the void. A lip or upper surface around an opening in the void overhangs at least a portion of the cushion insert, thereby minimizing the size and corresponding negative effects of a transition area where the base and the insert overlap.

TECHNICAL FIELD

The present disclosure relates generally to seat cushions, and particularly relates to seat cushions of the type commonly used with wheelchairs.

BACKGROUND

Wheelchair users who spend a large portion of their day seated in a wheelchair are at risk of developing pressure ulcers (i.e., skin tissue breakdown) in their buttocks region. Pressure ulcers tend to occur in skin tissue that contacts the seat cushion near the bony prominences of the hip. Regions most prone to developing pressure ulcers include skin surrounding the ischial tuberosities, coccyx, and sacral area. A disabled wheelchair user, particularly one with partial or complete paralysis, is more likely to develop pressure ulcers because he or she lacks supportive muscular tissue that surrounds and protects the bony prominences of the buttocks. This problem is compounded by poor circulation and an inability to reposition during seating. Pressure ulcers cause severe discomfort and may pose a serious health risk to the wheelchair user.

Attempts have been made to provide wheelchair seating that reduces the likelihood of pressure ulcers. Seat cushions have been developed in an effort to eliminate pressure hotspots (i.e., a center of high pressure within a larger area of relatively low pressure) by pressure redistribution at the bony prominences in contact with a cushion.

One family of cushions uses a fluid membrane sack in conjunction with a foam cushion base as a means of supporting the user. The fluid membrane sack, which contains a gel or liquid-like substance, is intended to support the buttocks under hydrostatic (or otherwise generally evenly distributed) pressure. The fluid is typically contained within one or more thin pliable membrane sacks. The fluid is permitted to flow around the contour of the buttocks, with the bony prominences supported by the fluid, so that the entire region supported by the fluid experiences substantially the same level of pressure.

Another family of cushions uses an air-cell bladder in concert with a foam cushion base as a means of supporting the user. The air-cell bladder is intended to support the buttocks by evenly distributing air pressure in the air-cells in much the same way as with the fluid membrane sack.

One limitation to the efficacy of both of these families of cushions is the transition zone that exists at the region in which the bladder/sack and the foam base converge. When two different materials are used in a cushion, and more particularly on the seating surface of the cushion, the points wherein these two materials come in contact with each other or are attached to each other create a transition area. Generally, the physical properties of these two materials are significantly different in the transition areas and the performance and comfort of the cushion is reduced. When the user sits on a cushion, the cushion base and cushion insert both compress, but, due to the difference in physical properties that exist between the cushion base and cushion insert, they compress differently and produce uncomfortable differences in pressure on the user's body.

Current cushions focus on either the type of pressure relieving mediums (gel, fluids, air) or the types and shapes of the cushion foam base.

SUMMARY

One aspect of the present disclosure relates to a hybrid seating cushion made up of at least a cushion base and a bladder. The cushion base may have a seating surface. The seating surface may have a lip edge overhanging a void in the cushion base. The bladder may be positioned in the void and may have an outer wall extending at least partially under the lip edge.

In some embodiments, the bladder may be made of a plurality of at least partially separate cells. These cells may be interconnected by a plurality of pressure-distributing passages. When a user is seated on the seating surface, the bladder may be configured to support an ischial tuberosity, a coccyx, and/or a sacral area of the user. In some arrangements, the lip edge of the cushion is pointed inward in relation to an opening of the void. The lip edge may also at least partially form a transition surface between a sidewall of the void and the seating surface.

In another embodiment, a hybrid seating cushion is provided that may be made of a cushion base and a bladder. The cushion base may include a seating surface and a void formed at least in part by an interior sidewall of the cushion base. The void may be accessible at or along the seating surface. The bladder may be positioned within the void. An interior sidewall of the cushion base void may extend over at least a portion of an outer wall of the bladder, such as when the bladder is positioned in the void.

In some configurations, the seating surface and the sidewall of the cushion base may intersect at an angle of less than 90 degrees. The sidewall may be concave shaped. An outer wall of the bladder may be at least partially sloped, and at least a portion of the sloped outer wall of the bladder may be positioned under the interior sidewall of the cushion base.

In some embodiments, the void extends completely through the cushion base from the seating surface to an oppositely-positioned bottom surface, but in other embodiments the void extends partially through a thickness of the cushion base.

In some cases, when the seating surface is under vertical compression at least a portion of the interior sidewall of the cushion base may overlap at least a portion of the outer wall of the bladder. In other cases, when the seating surface is under compression at least a portion of the interior sidewall of the cushion base may be pressed into contact with at least a portion of the outer wall of the bladder.

In yet another embodiment, a hybrid seating cushion is disclosed which includes a cushion base and a bladder. The cushion base may include a seating surface and void in seating surface, wherein the void may have a side wall. The intersection of the seating surface and the side wall may form an angle of less than 90 degrees. The bladder may be positioned within the void. When a user is seated on the seating surface, a transition area between the cushion base and the bladder may be filled with at least a portion of the cushion base and at least a portion of the bladder.

In some of these embodiments, the seating surface and the side wall may intersect at an angle between about 70 degrees and about 90 degrees.

In some arrangements where a user is seated on the seating surface, at least a portion of the cushion base fills the transition area between the user and the at least a portion of the bladder. In some embodiments, the bladder may be positioned within the void by attachment of the bladder to a lower surface of the cushion base, such as a surface of the cushion base below the seating surface.

In another embodiment, a method of manufacturing a hybrid seating cushion is disclosed. The method may include the steps of providing a cushion base and a bladder, wherein the cushion base has a seating surface and the bladder has an outer wall; forming a void in the seating surface, wherein the void has a lip edge and is sized to receive the bladder; and positioning a bladder within the void, wherein at least a portion of the outer wall of the bladder is positioned under the lip edge of the cushion base.

In some embodiments of the method, the fill level of a fluid within the bladder may be adjusted. This may entail attaching the bladder to a lower surface of the cushion base, such as a surface of the cushion base below the seating surface. The step of providing the bladder may additionally include providing a plurality of at least partially separate cells in the bladder. The step of forming the void may additionally include forming an interior sidewall in the void, wherein a plane of the interior sidewall and a plane of the seating surface are formed to intersect at an angle of less than 90 degrees. The step of forming the void may additionally include forming the void to extend partially or completely through the cushion base.

The foregoing and other features, utilities, and advantages of various embodiments will be apparent from the following detailed description and with reference to the accompanying drawings.

Throughout the drawings, identical reference numbers designate similar, though not necessarily identical, elements.

DETAILED DESCRIPTION

The present disclosure is directed to cushions for seating and related methods. An example application is a cushion base that may be used for a seat in a wheelchair. For instance, the cushion for seating may include a seating surface with a void having an inset fluid bladder system. One feature of certain embodiments described herein shows that to obtain optimal cushion performance, the transition area may be eliminated or reduced to an insignificant size, thereby reducing or eliminating pressure concentrations on the user's body resulting from the transition area.

The sides of the void in the cushion may be formed so that when a user is seated on the seating surface, the sides are urged toward the outer portions of the bladder system and fill the transition area between the different materials. As a result, the user may have a more comfortable seating surface due to optimal cushion performance at the transition area. Accordingly, the present disclosure may eliminate the adverse effects that exist in cushion and seating systems that are constructed with at least two different mediums or materials in the cushion base.

As used herein, an “aperture” may refer to a space within a material or outer body. The aperture may be bounded by an outside perimeter of the material such as sidewalls of a through-hole or tunnel passing through the material. An aperture may therefore be interchangeably referred to as a “through-hole” or “hole” in a material.

As used herein, a “cavity” may refer to a space in a material that does not pass through the material completely. For example, a cavity may be a space in a material that does not have two open ends, but the space may have an open end and a closed end. In another example, a cavity may be a space bounded on its sides and bottom by the material and has one or more openings at one surface or side of the material.

As used herein, a “void” may refer generally to an aperture, a cavity, or both within a material or outer body. An “indentation” is a shallow cavity in the material. For example, the bottom surface of an indentation (i.e., the surface below an opening in the material) may be narrower or equal in width to its opening. The internal width of a void, aperture, or cavity may vary along its length or depth.

An “opening” refers to a space in a surface of a material, such as, for example, the entrance to or exit from a void in a material. An “opening” may alternatively refer generally to the aperture, cavity, or void of which the space in the surface is a part.

A void in the cushion may extend partially or completely through the cushion body. Typically, a void is formed in the cushion so as to be under the regions most prone to developing pressure ulcers, including skin surrounding the ischial tuberosities, coccyx, and sacral area. A cushion insert (e.g., a bladder or other fluid membrane sack) may be positioned in the void so that at least a portion of a side of the bladder is underneath a lip edge running along at least part of an opening at the seating surface of the cushion. When vertical pressure is applied to the seating surface, such as when a user is seated on the cushion, the pressure drives the lip edge downward toward the side of the bladder, thus either contacting the bladder or approaching the bladder and thereby greatly reducing the transition area by filling it with the lip and bladder. Thus, the user's buttocks region may be effectively supported by multiple cushion materials and by multiple cushion insert fill levels without the discomfort of a large transition area or exposed outer edge of a bladder touching his or her body.

In some embodiments, the sides void in the cushion are shaped to collapse toward the cushion insert due to being shaped to make an angle of less than 90 degrees with the seating surface. This reverse tapering of the side walls around the cushion insert may cause the side walls to flex downward and/or inward when under vertical pressure. Since the cushion insert is positioned inward or underneath the lip edge of the opening in the seating surface, the space between the insert and the cushion base decreases. In other embodiments, the side walls may be concaved, curved, or otherwise shaped to permit outer and/or peripheral portions of a bladder insert to lie under the edge of the seating surface.

The present disclosure illustrates a wheelchair cushion, but it is not limited to wheelchairs. Features of embodiments described herein may also be adapted to, without limitation, seating for cars, trucks, boats, trains, or motorcycles, as well as any furniture, portable cushions for seating, and all other cushion and seating applications.

To assist in illustrating functional and structural differences between prior art cushions and embodiments of the present disclosure, an illustrative cross-section view of a seating cushion and bladder portion is shown inFIGS. 1A-1C. The cushion base102has an upward-facing seating surface104in which an indentation106is formed. A multi-cellular bladder114,116,118is positioned or attached in the indentation106and provides a different level of support to a seated user in comparison to the cushion base102. For example, the bladder114,116,118may be filled with air or a gel, and the cushion may be comprised of semi-rigid foam, such as Ethafoam or foam rubber. The outer edge110of the bladder114,116,118is exposed to a user seated on the seating surface104and a top surface112of the bladder.

When a user is seated on this hybrid cushion100, the bladder114,116,118and cushion base102compress at different rates. The bladder114,116,118itself may be configurable to provide different levels of support, from a fully-filled bladder114shown inFIG. 1A, to a partially-emptied bladder116shown inFIG. 1Bor an even more emptied bladder118shown inFIG. 1C. As indicated by the circled transition areas120, the inflation level of a bladder114,116,118affects the size of the transition areas120between the seating surface104and the top surface112of the bladder114,116,118.

The transition areas120are often a source of discomfort for users due to the presence of the edge110of the bladder114,116,118, which in some cases may buckle or bend into ridges or ripples that come into contact with the user, thereby producing undesirable pressure concentrations, scratching, or pinching. Furthermore, the transition areas120may act as open spaces below the seating surface104and top surface112that allow portions of the user's skin to be unsupported or pinched by adjacent cushion and bladder portions, leading to uncomfortable seating and potentially hazardous skin conditions. While deflating the bladder114,116,118incrementally improves comfort by reducing the size of the transition areas120as shown inFIG. 1C, flexibility of the bladder114,116,118is simultaneously reduced, hindering the ability of the bladder114,116,118to displace and conform yet still support the user's body. Furthermore, the transition areas120are never fully eliminated, even after completely emptying the bladder.

FIGS. 2-4show various views of a hybrid cushion200and cushion base202according to an embodiment of the present disclosure.FIG. 2is a perspective view of a hybrid cushion200including a cushion base202. The cushion base202may have an upward-facing seating surface204and outer sides206. The seating surface204may include a contoured region208to distribute pressure from a user's body (e.g., his or her upper leg areas) across the seating surface204. The seating surface204may be tapered, curved, or rounded at a front edge210. The contoured region208may be beneficially positioned on the front, sides, and back of the seating surface204so as to provide postural support and a reduction in peak pressures, for the user. This contour provides postural support as well as reduces peak pressures and hot spots on the cushion.

The cushion base202may comprise a soft foam material. For example, the cushion base202may comprise a flexible, soft material or medium capable of distributing weight of a seated user. Example materials for the cushion base202may include, for example and without limitation, a semi-rigid foam material made of natural or synthetic materials, such as polyurethane foam, latex foam rubber, viscoelastic foam, rest-suspended foam, reticulated polyurethane foam, lux foam, bonded foam, another foam rubber, cellular rubber, or an inflatable air or fluid bladder. The formation of the cushion base may include at least one material, but the cushion base may include multiple materials, including multiple foams. A semi-rigid foam may not flex into and fill the transition area. Thus, the cushion base may be an air bladder that is filled to a different pressure than the insert air bladder.

An opening212may be defined in the cushion base202. For example, the opening212may be in the seating surface204and form a void214within the cushion base202. The void214may have at least one sidewall216surface. The opening212may have a lip218running around at least a portion of the interface between the seating surface204and the sidewall216. In some embodiments, the shape of the lip218may be a pointed edge running around one or more portions or sides of the opening212(see, e.g.,FIG. 4). For example, the sidewall216and seating surface204may intersect to form a pointed lip218. The lip218may be pointed inward to the opening212, thereby making a portion of the void214below the lip218wider than the opening212, as shown inFIG. 4. In some embodiments, the lip218edge may be rounded, filleted, chamfered or take another transition shape where the seating surface204meets the sidewall216. Doing so may provide at least the benefit of a more gradual transition between the seating surface and an upper surface of a cushion insert220. In some embodiments, the lip218may be formed as part of a transition surface or sidewall portion that may be substantially perpendicular to the seating surface204, as described in further detail in connection withFIG. 7A.

The opening212may be advantageously positioned in the rear area219of the seating surface204of the cushion base202so as to be positioned under the user's ischial tuberosities, coccyx, and/or sacral area when the user is seated on the seating surface204. Thus, with a cushion insert220or bladder in position in the opening212or void214, those weight-bearing portions of the user's body may receive more comfortable support. In some embodiments, the opening212may be beneficially positioned elsewhere on the cushion, such as at a point of user-weight-bearing significance or at another point susceptible to development of ulcers or other pressure-related ailments.

A cushion insert220may be positioned in the void214of the hybrid cushion200. The cushion insert220may include a resilient bladder filled with air, gel, a liquid, or another gas or fluid. In some configurations, the bladder may be sealed, but in other configurations it may be adjustably filled or emptied by a user. The bladder may be beneficially comprised of a polymer, neoprene rubber, natural or synthetic rubber, PVC, latex, or other flexible elastomeric material that allows flexible expansion and contraction of the bladder and permits the bladder to comfortably conform to and support the shape of a user seated on the hybrid cushion200. The cushion insert220may comprise multiple partitions222. The partitions may be separate from each other, but in some arrangements, at least some of the partitions may be in fluid communication with each other. For example, if the partitions222are in fluid communication with each other, air or another fluid or gel within the partitions222may redistribute among the partitions222to better distribute the weight borne by the cushion insert220.

In some embodiments, the cushion insert220may further comprise a fill tube224. The fill tube224may extend from the cushion insert220to an easily accessible outer area of the cushion base202, such as one of the outer sides206. The user may introduce or remove fill fluid for the cushion insert220through the fill tube224, thereby managing or adjusting the amount of the material stored within the cushion insert220. The end of the fill tube224may include a valve226operable to control the inflow and/or outflow of material from the cushion insert220through the fill tube224.

FIG. 3is a top plan view of a cushion base202according to an embodiment of the present disclosure. The cushion insert220is not shown inFIG. 3. The outer sides206of the cushion base202and the wide perimeter302of the lower portion of the void214sidewall216are shown. The void214in this embodiment is shown as a through-hole or aperture that extends through the entire thickness of the cushion base202. In other embodiments, the void214may extend partially through the cushion base202, such as is shown inFIGS. 8-9.

Additionally, there is only one void214shown inFIG. 3, but in other embodiments, multiple voids may be formed in the cushion base202. Multiple voids may be beneficial to provide different bladder inserts at different portions of the cushion base202(e.g., multiple cushion inserts having various levels of internal pressure or fill materials) or to allow the cushion base202material to provide additional support to areas between multiple cushion inserts. The void214has an opening212at the seating surface204and underneath the cushion base202. In other embodiments, the void214may comprise a passage through the cushion base202having multiple openings in a single surface. For example, the void214may have two openings in the seating surface that are connected by a passage within the cushion base202.

FIG. 4is a section view of the cushion base202ofFIG. 3taken along section lines4-4inFIG. 3.FIG. 4shows the reverse taper of the sidewall216of the void214, where the sidewall216is at an angle230with respect to a vertical. In some embodiments, the angle230is between greater than 0 degrees and about 45 degrees. In other embodiments, the angle230may beneficially be between greater than 0 degrees and about 20 degrees. The lip edge218in this figure is shown pointed, but it may be chamfered, filleted, rounded, or take another transition shape, as described above. In some embodiments, the lip edge218overhangs a portion of the void214such that at least a portion of the sidewall216is wider than the lip edge218. For example,FIGS. 3 and 4show that the wide perimeter302at the bottom edge of the sidewall216is wider than the lip edge218. Thus, when a cushion insert (not shown) is positioned in the void214, the lip edge218and sidewall216may be between the seating surface204and the outer edge or sides of the insert.

FIGS. 5A-5Cshow an exemplary embodiment of a hybrid cushion for seating under various levels of compression.FIG. 5Ashows an uncompressed hybrid seat cushion500with a filled cushion insert520,FIG. 5Bshows a partially compressed hybrid seat cushion500with a partially emptied insert520, andFIG. 5Cshows a deeply compressed hybrid seat cushion500with a significantly emptied insert520. Thus, three fill levels of the cushion inserts520are shown. A cushion base502is shown attached to the cushion insert520in each instance. The cushion base502may have a seating surface504on an upward-facing portion of the base. A through-hole or aperture512may extend through the thickness of the cushion base502. A cushion insert520is positioned in the aperture512. The cushion insert520may include multiple connected fluid-bearing partitions522which may or may not be in fluid communication with each other, as described in connection with the partitions222ofFIG. 2. The cushion insert520may have an outer edge portion521attached to the cushion base502on a portion of the cushion base502opposite the seating surface504. The aperture512of the cushion base502includes a sidewall516and a pointed lip518. The sidewall516is adjacent to the side surface532of a partition522of the cushion insert520. The sidewall516may be angled or tapered as shown such that the lip518is above at least a portion of the side surface532of partition522.

InFIG. 5A, the height550of the cushion base502is uncompressed. In this uncompressed state, the lip518may be essentially in-plane with the top of the partitions522when the partitions522are fully filled or inflated. The sidewall516tapers outward from the lip518to the lower perimeter528of the aperture512in the cushion base502in a direction from a central point on the cushion base502toward an outer periphery of the cushion base502. This relationship between the cushion base502and the cushion insert520may provide many benefits to the operation and use of the hybrid cushion500. For example, the even height of the partitions522and seating surface504may allow covers and top-cushions to be easily installed around the cushion500without interference of bulges or indentations in the general top surface of the cushion500. Further, the transition area556between the cushion insert520and the cushion base502is small, minimizing the negative effects of large openings or spaces between the cushion base502and the cushion insert520. Additionally, the outer edge portion521of the cushion insert520is not adjacent to the seating surface504, so a seated user is much less likely to be able to feel any effects from potential rippling, bending, or ridges in the edge portion521. Such deformities in the outer edge portion521may be dampened or absorbed by deflection of the cushion base502.

InFIG. 5B, the cushion base502is partially compressed, as shown by reduced height552. Thus, the cushion base502may have a reduced height552where a user is seated. The partitions522of the cushion insert520are partially deflated or emptied. Under pressure on the seating surface504, the lip518and sidewall516of the cushion base502deflect inwardly toward the upper opening of the aperture512due to being angled in their uncompressed state (e.g., as shown inFIG. 5A). They are predisposed to move in that direction starting from their uncompressed state. While under compression, the lip518is driven downward and inward over a top portion of the partially deflated cushion insert520. Thus, even with pressure applied to the seating surface504, the transition area556may be small, and may even be reduced or unchanged from the configuration ofFIG. 5A, despite the deflation of the cushion insert520.

With a roughly consistent size of transition area556across multiple fill levels of the cushion insert520, the user may receive a relatively consistent, predictable feel and level of comfort while still being able to adjust the fill of the cushion insert520to provide a customized amount of cushion feedback. In some embodiments, the lip518may be driven into contact with the side surface532of a partition522, thereby reducing the transition area556even more.

The outer edge portion521inFIG. 5Bof the cushion insert520remains set off from the seating surface504, providing a buffer between the user and the potential discomfort of contact with the edge portion521.

FIG. 5Cshows the cushion base502deeply compressed, as shown by reduced height554. The cushion insert520is also even more emptied in comparison toFIGS. 5A and 5B. Again, the lip518and sidewall516of the cushion base502may deflect inward toward the opening of the aperture512. The transition area556is still generally consistent in size withFIGS. 5A and 5B, even though the shape of the cushion base502and the shape of the cushion insert520have changed dramatically. The transition area556is filled with a combination of the cushion insert520and the cushion base502, as in previous examples and embodiments.

The outer edge portion521inFIG. 5Cof the cushion insert520remains set off from the seating surface504, providing a buffer between the user and the potential discomfort of contact with the edge portion521.

FIG. 6Ashows a cross-section view of a portion of a hybrid cushion600. A single pocket622is shown in the cushion insert620positioned in the aperture612of the cushion base602. The cushion base602is not compressed. The pocket622may be filled with a fluid, such as, for example, a gas, gel, or liquid, as described in more detail in relation to bladders and other cushion inserts above. The lip618of the upper opening of the aperture612is lower than the top of the pocket622of the insert620relative to the bottom of the hybrid cushion, but still lies over at least a lower portion632of the side of the pocket622. An upper portion634of the side of the pocket is not positioned below the lip618. Regardless, when a user is seated on the hybrid cushion600, deflection of the cushion base602will still drive the lip618into or nearer to the pocket622, reducing or preserving the size of a transition area636between the base602and the insert620.

FIG. 6Bshows a cross-section view of a portion of the hybrid cushion600ofFIG. 6Awhere the single pocket622is partially deflated and the cushion base602is uncompressed. Lip618of the cushion base602now overhangs both portions632,634of the side of the pocket622. In this configuration, a seated user may still compress the cushion base602, thereby driving the lip618into contact or near to the portion634on the side of the pocket622. The transition area in this case would be substantially similar in size to transition area636ofFIG. 6Asince the cushion insert620is at least partially underneath the lip618. The relative height of the lip618in an uncompressed position and the top of the pocket622of the cushion insert620in an uncompressed position may have little effect on the performance of the cushion (as measured by effect on the transition area (e.g., transition area636)).

FIG. 6Bshows an exemplary view of how a cushion base602may appear in relation to a partially-deflated cushion insert620when the cushion base602is not subject to downward surface pressure (e.g., the weight of a seated user). In contrast, previousFIGS. 5B and 5Cshow the cushion base502under compression. InFIG. 6B, the lip618may be relatively farther from the side of the cushion insert620(e.g., upper portion634) in the uncompressed position, for example, in comparison to the compressed lip518and side532of the hybrid cushion500ofFIG. 5C. Thus,FIG. 6Bmay illustrate that, for purposes of comparing one transition area to another (e.g., when comparing the size of transition area556to the size of transition area636), the size and features of a transition area of a hybrid cushion are to be determined when the cushion base602is subjected to typical downward surface pressure loading conditions. For example, to determine characteristics of the transition area of the hybrid cushion600inFIG. 6B, the cushion base602may be compressed, driving the lip618on the cushion base602and the surfaces of the cushion insert620into the positions they normally assume while under a typical load, and the area of transition between the cushion insert620and cushion base602may then be examined.

This method of examining the transition area may be beneficial because cushion elements (e.g., insert620or base602) may have significantly differing geometries based on the flexibility of the materials of which they are comprised. For example, a cushion base602may be much thicker in an uncompressed state when it is comprised of a viscoelastic foam than a cushion base602comprised of a relatively rigid bonded urethane foam, but when these cushion bases602are each under a typical load, their compressed thicknesses may be identical. Therefore, the transition areas of each of the bases602may be identical, so it may be preferable to examine the transition area of each base602when under load to get an accurate understanding of how the transition area would affect the comfort of a seated user.

FIG. 7Ashows an embodiment of a hybrid cushion700having an alternative configuration of the lip718and sidewall716of a cushion base702. The cushion base702is uncompressed, and the cushion insert720is fully inflated and positioned in the aperture712in the cushion base702. The seating surface704may be separated from the lip718by a transition surface734. The transition surface734may be a generally vertical offset between the lip718and the seating surface704, as shown, or may be tapered. For example, the transition surface734may be sloped downward, sloped upward, curved, beveled, stepped, or take another shape transitioning between the seating surface704and the lip718. In this manner, the shape of the cushion base702is configurable to prevent unnecessary pinching of the user or other materials on top of the seating surface between the lip718and a partition722of the insert720. In some embodiments, the transition surface734is omitted, so the lip718is directly at the seating surface704. In other embodiments, the lip718is rounded and defined as either the tip of the rounded surface or a point below the tip where the top of the aperture712transitions into the sidewall716.

The sidewall716of the aperture712may be concave, thereby potentially more closely following the shape of an insert720as it is deformed by filling or emptying. For example, the curved sidewall716of hybrid cushion700shown inFIG. 7Bclosely follows the curved side surface732of the insert720. This may affect the lateral inward deflection of the lip718in comparison to a sidewall716that is straight and sloped. This property is illustrated in the lateral inward deflection of lip518acrossFIGS. 5A and 5Bwhen compared to the deflection of lip718acrossFIGS. 7A and 7B. Differences in deflection of the lip718may reduce wear on the foam cushion base702due to different levels of stretching of the seating surface704as the lip718and side of the insert720collapse into the transition area756when under pressure. Additionally, a concave sidewall provides less support below the lip718than a comparable angled surface (e.g., sidewall516shown inFIGS. 5A-5C), so the transition area around the lip718may be more flexible and collapsible into the insert720. This flexibility and collapsibility are variable characteristics that may be designed for optimal comfort of the hybrid cushion at the transition area756.

In some arrangements, the curved sidewall716perpendicularly intersects the bottom of the cushion base702. In some arrangements, the sidewall716intersects the bottom of the cushion base at an angle (e.g., an angle complementary to the angle402shown inFIG. 4). Thus, the curved surface716may have a plurality of radii of curvature, including an infinite radius of curvature. For example, infinite curvature may be present when the curve turns into a flat plane at the bottom intersection point or where the sidewall716meets the lip718.

FIG. 8is a top plan view of a cushion base800according to another embodiment.FIG. 9is a cross-section view of the cushion base800taken along section lines9-9shown inFIG. 8. The cushion base800has a contoured opening812in its seating surface804. The space below the opening812does not extend entirely through the thickness of the cushion base800, resulting in a cavity850in the cushion base800(seeFIG. 9). The cavity850may have a bottom surface852and sidewalls816. The bottom surface852of the cavity850in the cushion base800may be formed as an integral part of the cushion base800or it may be formed by attaching or gluing a sheet of material to the bottom of the cushion base800to form the cavity850. This sheet of material may be made of a variety of materials, including but not limited to foam, fabric, wood, metal, or plastic. In one embodiment, a foam cushion is provided having a thru-hole formed in the cushion to create a cavity, with a piece of fabric secured to the bottom of the foam cushion base. The sidewalls816may be angled outward from a lip818at the seating surface804to the bottom surface852, so that the bottom surface852spans an area wider than the lip818at the opening812for at least some portions of the cushion base800. In some arrangements, the sidewalls816may be concave or curved, as discussed in connection with sidewalls716ofFIGS. 7A-7Cabove.

In some embodiments, a cushion insert (not shown inFIG. 8 or 9) may be positioned in the cavity850. For example, the insert may be attached to or placed on the bottom surface852. The cushion insert may be beneficially shaped to have outer side wall portions lying at least partially under the sidewalls816, such that the lip818lies above at least a portion of the outer side portions of the insert when the insert is within the cavity850and the cushion base800is uncompressed. Benefits and specifications of the positioning of these elements are discussed in more detail above.

In another embodiment, a method of manufacturing a hybrid seating cushion may be provided. The hybrid seating cushion produced may be one of the hybrid cushions200,500,600,700,800described in connection withFIGS. 2-9. In one configuration, the method includes providing a cushion base and a bladder. The cushion base may have a seating surface, and the bladder may have an outer wall, similar to the elements previously described in connection withFIGS. 2-9. The cushion base may be a cushion suitable for use as a cushion for seating and comprise foam rubber or another similar material. The bladder may be a flexible cushion insert, sack, or other gel-, fluid-, or gas-bearing element capable of generally evenly distributing pressure on its top seating surface. The bladder may also comprise a plurality of separate cells or partitions which may or may not allow fluid flow between each other, as discussed above.

The method may further include forming an opening in the seating surface of the cushion base. For example, the opening may be carved from or cut out of a solid foam cushion base. In some arrangements, the cushion base may be pre-formed with a void fulfilling the requisite functions of the openings described above (see, e.g., opening812and openings for apertures212,512,612,712). In yet other embodiments, an aperture or cavity in the cushion base may be pre-formed or cut into the cushion base, and the step of forming an opening in the seating surface may require refining or modifying the dimensions or proportions of the pre-formed opening to receive the bladder according to the bladder thickness, width, and other dimensions.

The opening may define a lip edge which runs around at least a portion of the opening in the seating surface. In some embodiments, the lip edge may be at the intersection of a sidewall of the cavity or aperture in the cushion base and the seating surface. A plane of the interior sidewall and a plane of the seating surface may be formed to intersect at an angle of less than 90 degrees. In another embodiment, the planes may intersect at an angle in the range between about 45 degrees and less than 90 degrees. In yet another embodiment, the planes may intersect at an angle in the range between about 70 degrees and less than 90 degrees. For example, the planes of the sidewall and the seating surface may intersect at the lip edge at an angle of less than 90 degrees, thereby forming a point directed inward toward the opening in the cushion base (e.g., at least when viewed in cross section). In another example, the seating surface and the sidewall of the cavity or aperture through the cushion base may not directly intersect at the lip edge (see, e.g.,FIG. 7A) but at least a portion of the sidewall and seating surface form planes intersecting at an angle less than 90 degrees.

The opening may be sufficiently sized to receive at least a portion of the bladder. For example, the opening may be formed having a similar general shape and size as the outer portions of the bladder, such as a rectangular (or other shape) opening to receive a generally rectangular (or other corresponding shape) bladder. In embodiments having a cavity formed in the cushion base that does not extend completely through the thickness of the cushion base, the opening may need to have a depth sufficient to allow the bladder to be reached by the user's body when seated on the cushion and sufficient to allow at least a portion of the outer area of the bladder to be underneath the lip edge of the opening when the bladder is positioned in the opening. In some embodiments, it may be beneficial to form the opening in the seating surface so that when the bladder is positioned in the opening, the outer perimeter of the top of the bladder is followed closely in parallel by the lip edge, thereby reducing the size of the transition area between the cushion base and inserted bladder materials.

The method may also include positioning a bladder within the opening. For example, this step may comprise attaching the bladder to the cushion base so that at least a portion of the bladder is within the opening in the seating surface. The bladder may be glued to the cushion base. It may alternatively (or in addition) be stapled, sewn, attached by buttons, snaps, hook-and-loop fastener material, or secured to the cushion base by another removable or permanent attachment or fastening means. In some configurations, the bladder may be attached to a bottom surface of the cushion base, as shown, for example, inFIG. 5A. In other cases the bladder may be alternatively (or additionally) attached to an internal surface of a cavity (e.g., to surface852shown inFIG. 9) or to a side wall of the cavity or aperture (e.g., to sidewalls816or516). The bladder may also be referred to as attaching generally to a lower surface of the cushion base, such as being attached to a bottom surface of the cushion base, a surface near the bottom end of the aperture or cavity in the cushion base, another surface below the seating surface, or a surface that would not contact the user when he or she is seated on the cushion. In some embodiments, the bladder comprises an attachment surface or extension configured for connection to the cushion base. For example, the bladder may comprise an outer edge portion (e.g., outer edge portion521ofFIGS. 5A-5C).

Upon positioning the bladder in the opening, at least a portion of the outer wall of the bladder may be positioned under the lip edge of the cushion base. This may result in the lip edge being compressible into or toward the bladder when a user is located on the seating surface. This relationship between the cushion base and the bladder may provide a minimal transition area or zone between the seating surface of the cushion base and the seating surface of the bladder. It may also minimize the change in size or shape of the transition area when the bladder is partially or completely emptied.

The preceding description has been presented only to illustrate and describe embodiments of the principles described herein. It is not intended to be exhaustive or to limit the disclosure to any precise form disclosed. While this disclosure has been made with reference to certain specific embodiments and examples, it will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of this specification. The scope of the invention, as defined by the claims and disclosure, is intended to include all changes and modifications which do not depart from the spirit of the specification, including the claims. The words “including” and “having,” as used in the specification, including the claims, shall have the same meaning as the word “comprising.”