WO2005120420A1

WO2005120420A1 - Body support cushion

Info

Publication number: WO2005120420A1
Application number: PCT/DK2005/000354
Authority: WO
Inventors: Bente Leifermann; Randi Bach Jensen
Original assignee: Dan-Foam Aps
Priority date: 2004-05-28
Filing date: 2005-05-27
Publication date: 2005-12-22
Also published as: WO2005120420A8; JP4856630B2; JP2008500075A

Abstract

In some embodiments of the present invention, a seat cushion is provided, and includes a body of visco-elastic material, a cavity within the body, and a plug removal y received within the body. In some embodiments, the plug can also include visco-elastic material. The visco-elastic material of the body and plug can be visco-elastic foam having a density of no less than about 40 kg/m3 and no greater than about 130 kg/m3. Also, in some embodiments, the visco-elastic material of the body can have a hardness of no less than about 90 N and no greater than about 300 N, while the visco-elastic material of the plug can have a hardness of no less than about 30 N and no greater than about 80 N. In some embodiments, the plug and cavity include visco-elastic material having different hardnesses and/or densities.

Description

BODY SUPPORT CUSHION

Cross-Reference to Related Applications Priority is hereby claimed to Danish Patent Application Number PA 200400847 filed on May 28, 2004, the entire contents of which are incorporated herein by reference.

Background of the Invention Conventional body supports can be found in a wide variety of shapes and sizes, and are often adapted for supporting one or more body parts of a user. As used herein, the term "body support" includes without limitation any deformable element adapted to support one or more parts or all of a human or animal in any position. Examples of body supports include mattresses, pillows, and cushions of any type, including those for use in beds, seats, and in other applications. A seat cushion is one type of body support that is available in a number of different shapes and sizes, and is typically adapted to support the posterior, legs, and/or back of a person in a seated position. Although a number of design issues are presented that are unique to seat cushions (and that can be addressed in manners unique to seat cushions), many design issues of seat cushions are relevant to other types of body supports. Accordingly, seat cushions are described herein both by way of example and to present issues unique to seat cushions. Seat cushions can be decorative and/or can be used for comfort. For example, seat cushions can be used on chairs with relatively hard plastic, wood, or metal seat surfaces. As another example, seat cushions can be used on bleachers or other seating (e.g., in an arena, stadium, or other location for sporting events, concerts, and other activities) where a person may be seated for a relatively long period of time. Seat cushions are available in portable and non-portable form, and can be releasably or permanently attached to one or more portions of a chair, seat, or other structure. Some conventional seat cushions are generally round or square in shape, and are constructed of a single piece of foam material. Such seat cushions generally make sitting for longer periods of time more comfortable. However, such cushions typically are not well adapted or adaptable to various needs of a user. For example, some users may desire seat cushions adapted for particular physical conditions of a user, such as for users with hemorrhoids or for users recovering from surgery, infection, injury, or giving birth. In ma y cases, pain resulting from these conditions is temporary, and can be at least partially addressed by a seat cushion placed on top of a chair or other seating device. In other cases, such a cushion can be permanently connected to (e.g., can be a portion of) a chair or other seating device adapted for such physical conditions. By way of example only, United States Patent Number 4,761,843 (the '843 Patent) discloses a hemorrhoid supporting cushion assembly comprising a cushion on a supporting surface which may be a seat cushion assembly. The cushion in the '843 Patent is formed from a flexible envelope partially filled with a fluid, and is positioned on the supporting surface beneath a seated person. Lateral portions of the envelope containing the fluid extend beneath the seated person. The weight of the seated person causes the fluid in the lateral portions of the envelope to flow toward the central region of the envelope, where the fluid is forced upwardly beneath the anus to support the hemorrhoid. Proper support provided by the cushion is very dependent upon the exact position of the person on the cushion, and upon the physical characteristics of the person. Although seat cushions adapted for a user having a temporary or permanent physical condition are useful, many are not well suited for users not having such a condition. Therefore, many seat cushions are either not used or are only used temporarily for lack of alternative seat cushion designs. Also, some seat cushions are well adapted for the comfort of certain users based upon user size, body shape, hardness or softness preference, and other user characteristics. However, such seat cushions are typically not well adapted or adaptable for the comfort of other users based upon such user characteristics. In light of the above limitations and other shortcomings of conventional seat cushions, new seat cushions are welcome additions to the art. For similar and other reasons, body supports adapted for supporting other areas of the body are also welcome in the art.

Summary of the Invention Some embodiments of the present invention provide a cushion for supporting a user, wherein the cushion comprises a body comprising visco-elastic material, the body having a length; a width; and a thickness substantially smaller than the length and width; the body defining a cavity extending at least partially through the thickness of the body; and a deformable plug located within and at least partially filling the cavity of the body, wherein the deforaiable plug is removable from the cavity of the body, wherein the cushion has a first configuration in which the body and plug support the user when the plug is received within the cavity of the body, and a second configuration in which the body supports the user without the plug. In some embodiments, a cushion for supporting the posterior of a seated person is provided, and comprises an annular body comprising visco-elastic material having a density no less than about 40 kg/m³ and no greater than about 130 kg/m³; and a hardness of no less than about 30 N and no greater than about 80 N; a first side substantially facing the posterior of the seated person; and an opposite second side substantially facing away from the seated person, the annular visco-elastic body defining a cavity extending between the first and second sides of the annular visco-elastic body; and a plug removably received within the cavity of the annular visco-elastic body; wherein the cushion has a first configuration in which the annular body and the plug cooperate in supporting the seated person, and a second configuration in which the annular body alone supports the seated person. Some embodiments of the present invention provide a cushion for supporting a seated person, wherein the cushion comprises an annular body comprising visco-elastic material having a density no less than about 40 kg/m³ and no greater than about 130 kg m³; and a hardness of no less than about 30 N and no greater than about 80 N, the annular body defining a cavity extending at least partially through the annular body; and a removable cover substantially enclosing the annular body and extending across the cavity of the annular body. In some embodiments, a cushion having a cavity is provided, and has a shape that can be described with relation to three perpendicular planes (i.e., an XY, XZ, and YZ planes), wherein the cushion lies generally in an XY-plane. The cushion can have a cavity that, when the cushion is viewed in a direction peφendicular to an XY-plane (viewing an upper surface of the cushion), has a shape that is substantially symmetrical on either side of a YZ-plane peφendicular to the XY-plane and parallel with a forward/rearward direction of a person sitting on the cushion. When viewed in a direction peφendicular to the XY-plane, the cavity can also or instead have a shape that is asymmetrical in relation to a XZ plane peφendicular to the XY-plane and peφendicular to a forward rearward direction of a person sitting on the cushion. When viewed in a direction peφendicular to the XY-plane, in some embodiments the cavity has opposite ends of different sizes (i.e., one end being larger than the other). In some embodiments of the present invention, the cushion can effectively relieve or reduce user pain while being less dependent upon the positioning of a person on the cushion, and in some cases even less dependent on the physical stature of the user. Also, in some embodiments the cushion can be adapted for use in one or more forward/rearward orientations of a user seated on the cushion. As described above, in some embodiments the cavity is asymmetrical on opposite sides of an XZ-plane substantially peφendicular to an XY-plane in which the cushion generally lies. In such embodiments, the central area of the cushion can be used to relieve different types of pain in two or more different locations on a user's body, rather than just from a single location (e.g., from hemorrhoids another rectal pain source), and can do so while still providing satisfactory cushioning and support for other body parts abutting the upper surface of the cushion. More information and a better understanding of the present invention can be achieved by referring to the following drawings and detailed description. Brief Description of the Drawings FIGS. 1A and IB are perspective views of a cushion according to an embodiment of the present invention; FIG. 1C is a top plan view of the cushion illustrated in FIGS. 1A and IB; FIGS. 2 A and 2B are perspective views of a cushion according to another embodiment of the present invention; FIG. 2C is a top plan view of the cushion illustrated in FIGS. 2 A and 2B; FIG. 3 is a side view of the cushion illustrated in FIGS. 2A-2C; FIG. 4 A is a perspective view of a cushion according to another embodiment of the present invention; FIG. 4B is a perspective view of the cushion illustrated in FIG. 4A, shown with the cover removed; FIG. 5 is a perspective view of a cushion according to yet another embodiment of the present invention; FIG. 6 is a perspective view of the cushion illustrated in FIG. 5, shown with the cover removed; FIG. 7 is an exploded perspective view of the cushion illustrated in FIGS. 5 and 6; FIG. 8 is a top view of a portion of the cover illustrated in FIGS. 5-7; FIG. 9 is a bottom view of the portion of the cover illustrated in FIG. 8; FIG. 10 is a rear view of the portion of the cover illustrated in FIGS. 8 and 9; FIG. 11 if a front view of the portion of the cover illustrated in FIGS. 8-10; and FIG. 12 is a side view of the portion of the cover illustrated in FIGS. 8-11. Before the various embodiments of the present invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like "front", "back", "up", "down", "top", "bottom", and the like) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as "first", "second", and "third" are used herein and in the appended claims for piuposes of description and are not intended to indicate or imply relative importance or significance.

Detailed Description Various body supports according to some embodiments of the present invention are illustrated in FIGS. 1 A-12. The illustrated body supports are seat cushions, and are indicated generally at 10, 110, 210, and 310 in FIGS. 1A-12. Although the following discussion is with reference to seat cushions 10, 110, 210, and 310, it should be noted that the features and elements described and illustrated can be applied in any type of body support, including without limitation lumbar and other types of back supports, head supports, leg and arm cushions, mattresses, and any other type of body support suitable for supporting any portion or all of a user's body in any position. Many of the features and elements of the present invention find particular application in seat cushions as described herein. However, in other embodiments of the present invention, other types of body supports (including those mentioned above) can have one or more of the features and elements described and illustrated herein with reference to the illustrated seat cushions 10_> 110, 210, and 310. hi this regard, the seat cushions 10, 110, 210, and 310 illustrated in FIGS. 1 A-12 each have an orientation when in use (i.e., with a generally upwardly-facing surface upon which a user sits and an opposite generally downward-facing surface). However, the seat cushions 10, 110, 210, and 310 and other body supports having any of the features and elements described herein can have any other orientation in use. With reference first to the seat cushion 10 illustrated in FIGS. 1A-1C, the illustrated seat cushion 10 comprises a body 12 configured with a non-planar surface pattern of upright cone-like bodies 14 (hereinafter "cones") on an upper side 16 of the seat cushion 10, and has a substantially smooth and planar lower side 18. Also, the seat cushion 10 illustrated in FIGS. 1A-1C has a torus-like or donut-like shape with an asymmetric cavity 20 in a central area 22 of the seat cushion 10. The material of at least the body 12 of the seat cushion 10 is a visco-elastic foam material with suitable density and hardness, such as the material marketed under the name Tempur®. In the illustrated embodiment of FIGS. 1A-1C, the entire seat cushion 10 is made from the same material. With continued reference to FIGS. 1A-1C, the cones 14 can have a height of, for example, 5-50mm, in some cases can have a height of 10-50mm, and in some cases can have a height of 10-25mm. Also, the cones 14 can have a mutual spacing of, for example, 30-70mm, and in some cases can have a mutual spacing of 50mm. In the embodiment of FIGS. 1A-1C, the upper side 16 of the seat cushion 10 has a substantially convex surface structure. In other words, the middle part 24 of the upper side 16 is located at a higher level than a circumferential part 26 of the upper side 16. In this manner, the middle part 24 of the seat cushion 10 can provide greater support for a person sitting on the seat cushion 10 than the circumferential part 26. The seat cushion 10 can provide decfeasirig sϋpporf in^" a direction from the cavity 20 outward toward ^"the circumference of the seat cushion 10. The cavity 20 of the seat cushion 10 illustrated in FIGS. 1A-1C is asymmetric about an axis (e.g., Z-axis 28) passing through the cavity 20 and peφendicular to an XY- plane in which the seat cushion 10 generally lies. Also, the illustrated cavity 20 is asymmetric on either side of an XZ-plane peφendicular to the XY-plane, but is symmetric on either side of a YZ-plane peφendicular to both the XY-plane and the XZ-plane. Since the seat cushion 10 is asymmetric on either side of the XZ-plane, the seat cushion 10 is rotated 360 degrees about the Z-axis 28 to arrive at the same orientation with respect to a user and the environment. Therefore, to a user sitting on the seat cushion 10, the cavity 20 can provide different support depending upon the orientation of the seat cushion 10 (e.g., with respect to a forward/rearward direction of the user sitting on the seat cushion 10). In FIGS. 1 A-1C, the cavity 20 is generally egg-shaped. However, other shapes, such as a pear-shape, a triangular shape, etc. are possible. The shape and size of the cavity 20 in the seat cushion 10 illustrated in FIGS. 1 A- 1C may vary in accordance with the type of pressure relief intended or desired, as well as in accordance with the size of the person using the seat cushion 10. In the embodiment of FIGS. 1A-1C (and the other illustrated embodiments herein), the cavity 20 extends fully through the seat cushion 10. However, in different embodiments, the cavity 20 can be a concave depression in the seat cushion 10. Also, the cavity 20 can have side walls 30 extending into the seat cushion 10 (e.g., downward in the views of FIGS. 1 A-1C). Such side walls 30 may be inwardly-inclined toward the center of the cavity 20, or may be outwardly inclined away from the center of the cavity 20. Whether the cavity 20 extends through the seat cushion 10 or is instead a concave depression in the central area 22 of the seat cushion 10 depends upon the cushioning effect desired. Also, whether the side walls 30 of the cavity 20 are inwardly-inclined or outwardly-inclined also depends upon the cushioning effect desired. Increased cushioning effect can be obtained when the cavity 20 is a concave depression or when the side walls 30 of the cavity 20 are inwardly-inclined, while a decreased cushioning effect can be obtained when the cavity 20 extends through the seat cushion 10 or when the side walls 30 of the cavity 20 are outwardly-inclined. In some embodiments, the cavity 20 in the central area 22 of the seat cushion 10 extends through the seat cushion 10, and the side walls 30 of the cavity 20 are neither inwardly nor outwardly inclined. However, in alternative embodiments, the side walls 30 of the cavity 20 may be either inwardly or outwardly inclined. A cone of a selected cushioning material (not shown) can be inserted into the cavity 20. The cone can be of any elastic material suitable for a desired cushioning effect. Thus, the cone may be made of a visco-elastic material, of a highly elastic material, of a gel-like material, of a liquidly cushioning material or of a gaseous cushioning material. In some embodiments, the cone may be replaceable so that the cushioning effect of the cone may be adjusted depending upon the cause of pain suffered by the user and/or depending upon the weight and physical stature of the user. In some embodiments, the cavity 20 can be asymmetric to exhibit a larger area of the cavity 20 toward the backside of a user seated on the seat cushion 10 (e.g., where relief is desired in the rectal area, such as in connection with pain induced by hemorrhoids). In some embodiments, the cavity 20 can be asymmetric to exhibit a larger area of the cavity 20 toward the front of a user seated on the seat cushion 10 (e.g., where relief is desired in the genital areas, such as in connection with pain from vaginal rupture resulting from childbirth). Thus, by having a cavity 20 that is in the central area 22 of the seat cushion 10 and that is asymmetric in relation to the XZ-plane as described above, the same seat cushion 10 can ensure satisfactory cushioning and support of body parts abutting the upper side 16 of the seat cushion 10, while still being used for relieving different types of pain, rather than pain from a single area of the user or from a single condition (e.g., hemorrhoids). The seat cushion 10 may be provided with a tilt along a YZ direction, so that the upper side 16 of the seat cushion 10 is inclined relative to the lower side 18. Accordingly, the upper side 16 of the seat cushion 10 can be at a higher elevation toward a backside of a user seated on the seat cushion 10 than toward a front of the user seated on the seat cushion 10, or vice versa, depending upon the orientation of the seat cushion 10 with respect to the user. A raised cushion level at the backside of a user may be desirable in situations where user pain is located in the rectal area, because the weight of the user can be forced in a forward direction. Alternatively, a raised cushion level at the front of the user may be desirable in situations where user pain is located in the genital area, because the weight of the user can be forced rearwardly. The tilt of the seat cushion 10 can be sized for establishing an angle of between 0° and 30°. In some embodiments, the tilt of the seat cushion 10 can be sized for establishing an angle of between 0° and 15°. In some embodiments, the tilt of the seat cushion 10 can be sized for establishing an angle of between 0° and 10°. In some embodiments, an asymmetric cavity 20 can be oriented in a direction so that a larger area of the cavity 20 is located in a part of the seat cushion 10 having a raised level while a smaller area of the cavity 20 is located in a part of the seat cushion 10 having a lower level. If pain experienced by a user is not of a nature explicitly located in the rectal area

to design the seat cushion 10 differently, i.e., orienting the asymmetric cavity 20 in a direction so that a smaller area of the cavity 20 is located in a part of the seat cushion 10 having a raised level while a smaller area of the cavity 20 is located in a part of the seat cushion 10 having a lower level. FIGS. 2A-3 illustrate another embodiment of a seat cushion according to the present invention. This embodiment employs much of the same structure and has many of the same features as the embodiments described above and illustrated in FIGS. lA-lC. Accordingly, the following description focuses primarily upon those structures and features that are different from the embodiments described above. Reference should be made to the above description for additional information regarding the structure and features, and possible alternatives to the structure and features of the seat cushion 110 illustrated in FIGS. 2A-3 and described below. Structure and features of the embodiment shown in FIGS. 2A-3 that correspond to structure and features of the embodiment of FIGS. 1A-1C are designated hereinafter in the 100 series of reference numbers. The seat cushion 110 illustrated in FIGS. 2A-2C comprises a visco-elastic material configured with a non-planar surface pattern of upright cones 114 on an upper side 116 of the seat cushion 110, and with a substantially smooth and planar lower side 118. Also, the seat cushion 110 illustrated in FIGS. 2A-2C has a torus-like or donut-like shape with a symmetric cavity 120 in a central area 122 of the seat cushion 110. The seat cushion 110 illustrated in FIGS. 2A-2C is also provided with a symmetric cavity 120. The cavity 120 is mirror-symmetric both in the XZ-plane and in the YZ-plane. Due to the symmetry in the XY-plane, rotation of the seat cushion 110 around the Z-axis 128 has no effect on the cushioning effect of the seat cushion 110. Thus, to a user sitting on the seat cushion 110, the seat cushion 110 provides the same support independent of whether the seat cushion 110 is oriented in one direction or another relative to a forward rearward direction of the user seated upon the seat cushion 110. With continued reference to FIGS. 2A-2C, the cavity 120 has a circular shape. However, in other embodiments, different shapes (such as a square shape, an oval shape, a star-like shape, etc.) may be envisioned. Some of the shapes mentioned, such as the oval shape, will provide a different support depending upon whether the seat cushion ϊlό is oriented in one direction or another (such as oriented 90° relative to a forward rearward direction of a user seated upon the seat cushion 110). The seat cushion 110 may be provided with a tilt along a YZ direction as described in greater detail with reference to the embodiment illustrated in FIGS. lA-lC. Because the shape of the cavity 120 illustrated in FIGS. 2A-2C does not introduce any substantial difference in the cushioning effect as described above, an inclined upper surface may be advantageous in providing a differentiated cushioning effect to a user seated upon the seat cushion 110. FIG. 3 is a view of the seat cushion 110 in the XY-plane. The upper side 116 of the seat cushion 110 is shown, together with the declining height of the seat cushion 110 at the circumference of the seat cushion 110. The cone-like surface of the upper side 116 is also clearly shown. The lack of cones 114 in the central area 122 of the seat cushion 110 is due to the cavity 120 being provided in the central area 122 of the seat cushion 110. FIGS. 4A-4B illustrate another embodiment of a seat cushion according to the present invention. This embodiment employs much of the same structure and has many of the same features as the embodiments described above and illustrated in FIGS. 1A-3. Accordingly, the following description focuses primarily upon those structures and features that are different from the embodiments described above. Reference should be made to the above description for additional information regarding the structure and features, and possible alternatives to the structure and features of the seat cushion 210 illustrated in FIGS. 4A-4B and described below. Structure and features of the embodiment shown in FIGS. 4A-4B that correspond to structure and features of the embodiments of FIGS. 1A-3 are designated hereinafter in the 200 series of reference numbers. Like the seat cushions 10, 110, 210 illustrated in FIGS. 1 A-3, the seat cushion 210 illustrated in FIGS. 4 A and 4B has a generally round, torus-like shape, and a cavity 220 (see FIG.4B) substantially centrally located in a body 212. The cavity 220 can have any shape desired, and in the embodiment of FIGS. 4 A and 4B has an elongated shape with one end of the cavity 220 larger than another end. The seat cushion 210 illustrated in FIGS. 4 A and 4B can comprise any elastic material, and in some embodiments comprises an elastic foam material. For example, the seat cushion 210 can comprise a reticulated or non-reticulated visco-elastic foam. A plurality of cones 214 extend from exterior surfaces of the body 212. However, unlike the cones 14, 114 of the seat cushions 10, 110 illustrated in FIGS. 1 A-3, the cones 214 of the seat cushion 210 illustrated in FIGS. 4A and 4B extend in a number of different directions. In some embodiments, at least some of the cones 214 extend in directions substantially peφendicular to that portion of the body 212 on which the cones 214 are located. Also, in some embodiments (such as that shown in FIGS. 4 A and 4B), substantially all of the cones 214 extend in such directions. It will be appreciated that the manner in which pressure is distributed across one or more surfaces of a user can differ based upon the shape of the cones 214 and direction in which the cones 214 extend from the body 212 of the seat cushion 210. The seat cushion 210 can also have a cover 232 (see FIG. 4 A) covering any amount of the body 212. For example, the cover 232 can substantially enclose at least an upper side 216 and a circumference of the seat cushion 210, or can enclose the seat cushion 210 on substantially all sides. The cover 232 can comprise any material or combinations of materials, such as nylon, polyester, and other synthetic materials, cotton, wool, and other natural fibers, and the like, any of which can be in a woven or non-woven form in the cover 232. In some embodiments, the cover 232 can be coated, such as with a wateφroof or vapor-proof layer of material. Such cover and coating materials are conventional in nature and are not therefore described further herein. Like the illustrated embodiments of FIGS. 1-3 described above, the seat cushion 210 illustrated in FIGS. 4A and 4B can have a plug (not shown) comprising the same or different material than that of the body 212. In some embodiments, the plug comprises an elastic material, and can comprise an elastic foam material such as reticulated or non- reticulated visco-elastic foam or any other elastic foam material. The plug can be shaped and dimensioned to be received within the cavity 220 in the body 212, and to be removed by a user when support in the area of the cavity 220 is not desired (or when the user desires to replace the plug with a plug having different material properties). The seat cushions 10, 110, 210 illustrated in FIGS. 1-4B each have a generally rotund shape. However, in other embodiments the seat cushions 10, 110, 210 can have any other shape desired, including without limitation square, rectangular, or other polygonal shapes, irregular shapes, and the like. An example of such an alternative shape is illustrated in FIGS. 5-12. FIGS. 5-12 illustrate yet another embodiment of a seat cushion according to the present invention. This embodiment employs much of the same structure and has many of the same features as the embodiments described above and illustrated in FIGS. 1A-4B. Accordingly, the following description focuses primarily upon those structures and features that are different from the embodiments described above. Reference should be made to the above description for additional information regarding the structure and features, and possible alternatives to the structure and features of the seat cushion 310 illustrated in FIGS. 5-12 and described below. Structure and features of the embodiment shown in FIGS. 5-12 that correspond to structure and features of the embodiments of FIGS. 1 A-4B are designated hereinafter in the 300 series of reference numbers. In the embodiment of the present invention illustrated in FIGS. 5-12, the seat cushion 310 has a generally flat and planar shape, and has a first end 334 with rounded corners 336 and a second end 338 with more shaφly-defined opposing comers 340. However, the seat cushion 310 can have any other shape suitable for use as a seat. _h some embodiments, the seat cushion 310 is not flat and planar, and can instead have concave or convex opposite sides, can have a shape corresponding to the posterior and/or legs of a user, can have any number of peaks, valleys, ribs, troughs, bumps, dimples, and/or other features on any side(s) of the seat cushion 310, and can have any other symmetrical or non-symmetrical shape or combination of shapes desired. For example, the seat cushion 310 can be or resemble a toroid with a hollow or solid center. As another example, the seat cushion 310 can be generally cuboid in shape with shaφ or rounded corners and or edges. As yet another example, the seat cushion 310 can be oval or egg- shaped. Still other seat cushion shapes are possible, and fall within the spirit and scope of the present invention. The seat cushion 310 illustrated in FIGS. 5-12 has a body 312, a plug 342, a sheath 344 (see FIG. 6), and a cover 332 (see FIGS. 5-7). The body 312 can be constructed of any cushion material or combinations of materials, including without limitation polyurethane or other types of foam, down, wool, husks, beads, and the like. In some embodiments, the body 312 includes visco-elastic foam. Temperature-sensitive visco- elastic foam can be used to provide increased adaptation to a user by virtue of the user's body heat, and can provide significantly improved user comfort in many cases. When compared to other types of foam, stuffing, and other cushion material, the visco-elastic foam of the body 312 can significantly improve pressure distribution of a user across the body 312. Such improved pressure distribution can reduce the opportunity for pressure ulcers to develop and can provide improved user support. Although any visco-elastic foam material can be used for the body 312, in many - cases, visco-elastic foam having certain material properties can provide improved performance results; In some eihDodimehts, ^' a v scό^elasϊic foam having a density of no less than about 40 kg/m³ and/or no greater than about 130 kg/m³ can provide good performance results. In other embodiments, a visco-elastic foam having a density of no less than about 70 kg/m³ and/or no greater than about 110 kg/m³ can provide good performance results. In still other embodiments, a visco-elastic foam having a density of no less than about 80 kg/m³ and/or no greater than about 90 kg/m³ can provide good performance results. Also, a visco-elastic foam having a hardness of no less than about 90 N and/or no greater than about 300 N can provide good performance results. In other embodiments, a visco-elastic foam having a hardness of no less than about 110 N and/or no greater than about 250 N can provide good performance results. In still other embodiments, a visco- elastic foam having a hardness of no less than about 135 N and/or no greater than about 170 N can provide good performance results. In some cases, the body 312 can be constructed of reticulated visco-elastic foam to achieve desired cushion characteristics, such as an increased heat distribution capability. The body 312 can be constructed of a single integral block of foam or can be constructed of two or more blocks of foam coupled together by adhesive or cohesive bonding material, tape, hook-and-loop fastener material, or in any other manner. The body 312 of the seat cushion 10 illustrated in FIGS. 5-12 has a single block of visco-elastic foam. As used herein and in the appended claims, the term "block" refers to a single integral piece of material having any shape or combination of shapes and manufactured in any manner. By way of example only, a block of the body 312 can be molded or cast in any manner, can be cut or machined to shape in any manner, can be extruded or pressed, can be manufactured in any combination of such operations, and the like. In some alternative embodiments, the body 312 can comprise a mass of granulated visco-elastic material retained within a cover (not shown) and having any of the body shapes described above. In such embodiments, the cover can comprise many different types of materials, including without limitation nylon, polyester, and other types of plastic, natural or synthetic rubber, cotton, wool, and any blend or other combination thereof. However, in some embodiments, a cover comprising visco-elastic material can provide additional benefits for the same reasons described above with reference to the visco-elastic material of the body 312 illustrated in FIGS. 5-12. Still other types of cover materials are possible, and fall within the spirit and scope of the present invention. The plurality of visco-elastic pieces can be generated by shredding or chopping visco-elastic material, and in some embodiments can have an average largest dimension of between 0.3 cm and 4 cm (although visco-elastic pieces having smaller or larger average sizes can be used, if desired). Also, the plurality of visco-elastic pieces can be reticulated or non-reticulated visco-elastic pieces. In some embodiments, the body 312 of the seat cushion 310 has a cavity 320 extending at least partially through the body 312. In this regard, the body 312 can be annular in shape. As used herein and in the appended claims, the term "annular" refers to a body having an internal cavity or recess open to the exterior of the body, and does not necessarily indicate or imply an exterior shape of the body (e.g., round, rectangular, irregular, and the like), the location of the cavity in the body (e.g., central, off-center, or otherwise), the shape of the cavity (e.g., round, rectanular, irregular, and the like), whether the cavity extends fully or partially through the body (i.e., defines a hole through the body or a depression on either side thereof), the cross-sectional shape (e.g., round, oval, rectangular, irregular, etc.) of the body at any circumferential position, or whether the annular shape is continuous or broken. The cavity 320 can have a depth (referring to the dimension of the cavity 320 extending in a direction into the body 312, such as in a direction substantially peφendicular to a plane in which the body 312 lies). The cavity 320 illustrated in FIGS. 5-12 is substantially centrally located in the body 312 of the seat cushion 310. However, in other embodiments, the cavity 320 can be located in any othe area of the seat cushion 310, and in some embodiments can be open to one or more peripheral edges of the body 312. For example, the cavity 320 can be located or extend toward the first and or second ends 334, 338 of the seat cushion 310, and in such cases can be adapted to provide pressure relief to different areas of auser (e.g., genital and or rectal areas of a user). Other cavity locations in the body 312 are possible, and fall within the spirit and scope of the present invention. The cavity 320 of the seat cushion 310 can have any shape desired, such as a rotund shape (see FIGS. 5-12), a rectangular o other polygonal shape, a peanut or hourglass shape, a star shape, an elongated shape, an irregular shape, and the like. Also, the cavity 320 can have any depth desired, such as a depth extending fully through the body 312 as shown in FIGS. 5-12, a blind cavity extending only partially through the body 312 (e.g., a depression in the body of the seat seat cushion 310). As mentioned above, the seat cushion 310 illustrated in FIGS. 5-10 has a plug 342, although such a plug 342 is not required in this embodiment or in the other embodiments of the present invention described herein. The plug 342 can be" shaped and dimensioned to be removably received within the cavity 320. The plug 342 can have a length (referring to the dimension of the plug 342 extending in substantially the same direction as the depth of the cavity 320 when the plug 342 is inserted within the cavity 320). The plug 342 can have any shape and size capable of being received within the cavity 320, including without limitation a rotund shape (see FIGS. 5-12), a rectangular or other polygonal shape, a peanut or hourglass shape, a star shape, an elongated shape, an irregular shape, and the like. In some embodiments, the plug 342 has a shape generally corresponding to the shape of the cavity 320 and/or is dimensioned to have a snug fit within the cavity 320. In this regard, a snug fit within the cavity 320 enables the plug 342 to be retained "within the cavity 320 without the assistance of another element or structure. The shujg fit can be generated by a plug 342 that is slightly larger than the cavity 320 in at least rie dimension. Depending at least in part upon the material of the body 312 and plug 342 hi some embodiments, the body 312 and/or the plug 342 can be resiliently deform'e tό insert the ■ ■ -. .-..• .. • .•- .- . ^'-^•. . . sv plug 342. Alternatively, the plug 342 can be dimensioned to have a clearance fit within the cavity 320. The plug 342 can be constructed of any cushion material or combinations of materials, including without limitation polyurethane or other types of foam, down, wool, husks, beads, and the like. Such material can be the same or different than the material of the body 312. In some embodiments, the plug 342 includes visco-elastic foam. Temperature-sensitive visco-elastic foam can be used to provide increased adaptation to a user by virtue of the user's body heat, and can provide significantly improved user comfort in many cases. Also, a visco-elastic foam for the plug 342 having a density of no less than about 40 kg/m³ and or no greater than about 130 kg/m³ can provide good performance results. In other embodiments, a visco-elastic foam for the plug 342 having a density of no less than about 70 kg/m³ and/or no greater than about 110 kg/m³ can provide good performance results. In still other embodiments, a visco-elastic foam for the plug 342 having a density of no less than about 80 kg/m³ and or no greater than about 90 kg/m³ can provide good performance results. Also, a visco-elastic foam for the plug 342 having a hardness of no less than about 30 N and/or no greater than about 80 N can provide good performance results. In other embodiments, a visco-elastic foam for the plug 342 having a hardness of no less than about 35 N and/or no greater than about 70 N can provide good performance results. In still other embodiments, a visco-elastic foam for the plug 342 ^"" having a hardness of hό less th abouf40N ahd/b nό^"gre er tK^ provide good performance results. In some embodiments, the plug 342 can be constructed of reticulated visco-elastic foam to achieve desired cushion characteristics, such as an increased heat distribution capability. When the plug 342 is inserted within the cavity 320 of the body 312, the plug 342 can occupy any amount of the cavity 320 desired. For example, the plug 342 can substantially entirely fill the cavity 320. Alternatively, the plug 342 can have a length shorter than the depth of the cavity 320, thereby defining a recess in the central area 322 of the upper and or lower sides 316, 318 of the seat cushion 310. A seat cushion 310 having such a recess can provide additional user comfort while still providing a degree of user support via the cushioning material of the plug 342. In some embodiments, a plug 342 having a length that is shorter than the depth of the cavity 320 can be insertable into a number of different positions (i.e., depths) within the cavity 320 in order to provide different degrees of central area support for the user. This adjustability can enable a user to adapt the seat cushion 310 to the user's preference. Also, the plug 342 can be removed and can be replaced by a different plug 342 having different dimensions (e.g., different lengths) and/or a different hardness, density, or other material property. This adjustability can further enable a user to adapt the seat cushion 310 to the user's preference. As described above, the body 312 of the seat cushion 310 can comprise a different material (i.e., a different type of material or the same type of material having different properties) than the plug 342. As also described above, the plug 342 can occupy less than the entire cavity 320 within the body 312. Accordingly, the hardness of the combined body 312 and plug 342 can be significantly different than the hardness of the plug 342 or the body 312 alone. In some embodiments, the hardness of the assembled body 312 and plug 342 is no less than about 50 N and/or is no greater than about 200 N. In other embodiments, the hardness of the assembled body 312 and plug 342 is no less than about 70 N and/or is no greater than about 150 N. In still other embodiments, the hardness of the assembled body 312 and plug 342 is no less than about 90 N and/or is no greater than about 120 N. As mentioned above, the body 312 of the seat cushion 310 (and the plug 342, if employed) can be at least partially enclosed with a sheath 344. The body 312 and plug 342 can be at least partially enclosed within respective sheathes 344 or within a single sheath 344 covering both the body 312 and plug 342. If employed, the sheath(es) 344 can comprise many different types of materials, including without limitation nylon, polyester, and other types of plastic, natural or synthetic rubber, cotton, wool, and any blend or other combination thereof. Still other types of sheath materials are possible, and fall within the spirit and scope of the present invention. The sheath(es) 344 can be vapor and/or liquid permeable or non-permeable, can be in any woven or non-woven form, and can be coated with any material desired. Also, in some embodiments, different portions of the sheath(es) 344 can comprise different types or forms of material connected together in any suitable manner, such as by stitching, adhesive or cohesive bonding material, hook-and-loop fastening material, and the like. In the embodiment illustrated in FIGS. 5-12, the body 312 and plug 342 each have a respective highly porous fabric sheath^'344 providing a reduced coefficient of friction for the body 312 and plug 342. The sheathes 344 can better enable insertion and removal of the plug 342 within the body 312, and/or insertion and removal of the body 312 and plug 342 within the cover 332. As also mentioned above, in some embodiments the seat cushion 310 is provided with a cover 332. The cover 332 can partially or fully enclose the body 312 (and plug 342, if used). The cover 332 can comprise many different types of materials, including without limitation nylon, polyester, and other types of plastic, natural or synthetic rubber, cotton, wool, and any blend or other combination thereof. Still other types of cover materials are possible, and fall within the spirit and scope of the present invention. The cover 332 of the seat cushion 310 can be vapor and/or liquid permeable or non-permeable, and can be in any woven or non-woven form. Also, the cover 332 can be coated with any material desired. In some embodiments, different portions of the cover 332 can comprise different types or forms of material. For example, the top of the cover 332 can comprise cotton, while the underside of the cover 332 can comprise a material providing reduced slippage between the seat cushion 310 and a surface upon which the seat cushion 310 rests (e.g., a natural or synthetic rubber sheet or coating, or a plastic material or coating providing an increased coefficient of friction). Any combination of cover materials can be used as desired. One or more fasteners can be used to install the cover 332 upon the body 312 (and plug 342, if used). Such fasteners can include snaps, hook-and-loop. fastening material, clasps, clips, buttons, ties, and the like used alone or in any combination, and can be used to permanently or releasably attach two or more portions of the cover 332 together after the body 312 and plug 342 have been inserted therein. Alternatively or in addition, such fasteners can be used to permanently or releasably attach the cover 332 to the body 312 or plug 342. By way of example only, the cover 332 illustrated in FIGS. 5-12 has a zipper 346 operable to open and close upper and lower portions of the cover 332 about the body 312 and plug 342. The zipper 346 or other fastener can be located anywhere on the cover 332, and in the illustrated embodiment of FIGS. 5-12 is located along a side wall of the cover 332. In some embodiments, the cover 332 is provided with one or more handles 348 for use in carrying the seat cushion 310. For example, the seat cushion 310 illustrated in FIGS. 5-12 has a handle 348 located at the first end 334 of the seat cushion 310. In other embodiments, the handle 348 can have any other location desired. In use, the seat cushion 310 can be permanently attached to a frame or other supporting structure, or can be used as a portable seat cushion 310 that can be placed in any location in which a user desires to sit. For example, the seat cushion 310 can be placed upon a chair, bench, wheelchair, car seat, bleacher seat, or other seating location. When a user desires to use the seat cushion 310 illustrated in FIGS. 5-12 with the plug 342 removed, the zipper 346 on the cover 332 can be opened to enable removal of the body 312 and plug 342. The plug 342 can be removed from the body 312 by grasping and pulling or pushing the plug 342 from the cavity 320. The body 312 can then be reinserted into the cover 332, after which time the zipper 346 can be refastened to enclose the body 312 within the cover 332. Alternatively, when a user desires to use the seat cushion 310 illustrated in FIGS.

5-12 with the plug 342 inserted, the zipper 346 on the cover 332 can be opened to enable removal of the body 312. The plug 342 can be inserted into the cavity 320 of the body 312, which in some embodiments includes deforming the plug 342 and or the body 312 in order to permit insertion of the plug 342. The assembled body 312 and plug 342 can then be inserted into the cover 332, after which time the zipper 346 can be refastened to enclose the body 312 and plug 342 within the cover 332. The constructions and aspects described above and illustrated in the drawings are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art, that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention as set forth in the claims. For example, although the seat cushions 10, 110, 210 illustrated in FIGS. 1-4B each have cones 14, 114, 214 on exterior surfaces of the seat cushions 10, 110, 210, it will be appreciated that such cones 14, 114, 214 need not necessarily exist in alternative embodiments of the present invention. Instead, any of the seat cushions 10, 110, 210 disclosed herein can have smooth, ribbed, dimpled, or other surface shapes, textures, and features as desired. The use of cones 14, 114, 214 can provide additional user comfort in some applications. Similarly, the seat cushion 310 illustrated in FIGS. 5-12 has substantially smooth exterior surfaces. However, in other embodiments, the body 312 and/or plug 332 can have cones on one or more exterior surfaces thereof, can have one or more ribbed or dimpled exterior surfaces, or can have any other surface shapes, textures, and features as desired. It is understood that the invention disclosed herein extends to all alternative combinations of two or more individual features disclosed herein. For example, each of the features and elements described and illustrated with respect to the embodiment of the seat cushion 310 illustrated in FIGS. 5-12 can be employed in the other embodiments disclosed herein (and vice versa). All of these different combinations are various alternative aspects of the present invention.

Claims

What is claimed is:

1. A cushion for supporting a user, the cushion comprising: a body comprising visco-elastic material, the body having: a length; a width; and a thickness substantially smaller than the length and width; the body defining a cavity extending at least partially through the thickness of the body; and _* a deformable plug located within and at least partially filling the cavity of the body, wherein the deformable plug is removable from the cavity of the body, the cushion having a first configuration in which the body and plug support the user when the plug is received within the cavity of the body, and a second configuration in which the body supports the user without the plug.

2. The cushion as claimed in claim 1, wherein the body is annular in shape.

3. The cushion as claimed in claim 1, wherein: the body comprises visco-elastic material having a density no less than about 40 kg/m³ and no greater than about 130 kg/m³; and wherein the visco-elastic material also has a hardness of no less than about 90 N and no greater than about 300 N.

4. The cushion as claimed in claim 1, wherein: the body has a shape; and the body comprises at least one block of visco-elastic material defining the shape of the body.

5. The cushion as claimed in claim 1 , wherein the body has a plurality of protrusions extending from an external surface of the body.

6. The cushion as claimed in claim 1, wherein the plug comprises visco-elastic material.

7. The cushion as claimed in claim 1 , wherein: the plug has a shape; and the plug comprises at least one block of visco-elastic material defining the shape of the plug.

8. The cushion as claimed in claim 1 , wherein: the cavity has a length extending in a direction through the thickness of the body; and the plug occupies less than the length of the cavity when installed therein.

9. The cushion as claimed in claim 1 , wherein the body has substantially flat first and second oppositely-facing surfaces between which is defined the thickness of the body.

10. The cushion as claimed in claim 1, further comprising a cover substantially enclosing the body and the plug, and extending across the cavity of the body.

11. The cushion as claimed in claim 10, wherein the cover is removable from the body and plug.

12. A cushion for supporting the posterior of a seated person, the cushion comprising: an annular body comprising: visco-elastic material having a density no less than about 40 kg/m and no greater than about 130 kg/m³; and a hardness of no less than about 90 N and no greater than about 300 N; a first side substantially facing the posterior of the seated person; and an opposite second side substantially facing away from the seated person, the annular visco-elastic body defining a cavity extending between the first and second sides of the annular visco-elastic body; and a plug removably received within the cavity of the annular visco-elastic body; the cushion having a first configuration in which the annular body and the plug cooperate in supporting the seated person, and a second configuration in which the annular body alone supports the seated person.

13. The cushion as claimed in claim 12, wherein the cavity extends through the annular body from the first side to the second side.

14. The cushion as claimed in claim 12, wherein: the annular body has a shape; and the annular body comprises at least one block of visco-elastic material defining the shape of the annular body.

15. The cushion as claimed in claim 12, wherein the annular body has a plurality of protrusions extending from an external surface of the annular body.

16. The cushion as claimed in claim 12, wherein the plug comprises visco-elastic material.

17. The cushion as claimed in claim 12, wherein: the plug has a shape; and the plug comprises at least one block of visco-elastic material defining the shape of the plug.

18. The cushion as claimed in claim 12, wherein: the cavity has a length extending at least partially through the annular body; and the plug occupies less than the length of the cavity when installed therein.

19. The cushion as claimed in claim 12, wherein the cover is removable from the annular body and plug.

20. The cushion as claimed in claim 12, wherein the first and second sides of the annular body are substantially flat.

21. A cushion for supporting a seated person, the cushion comprising: an annular body comprising visco-elastic material having a density no less than about 40 kg/m³ and no greater than about 130 kg/m³; and a hardness of no less than about 90 N and no greater than about 300 N, the annular body defining a cavity extending at least partially through the annular body; and a removable cover substantially enclosing the annular body and extending across the cavity of the annular body.

22. The cushion as claimed in claim 21, wherein: the annular body has a shape; and the annular body comprises at least one block of visco-elastic material defining the shape of the annular body.

23. The cushion as claimed in claim 21 , wherein the annular body has a plurality of protrusions extending from an external surface of the annular body.

24. The cushion as claimed in claim 21, further comprising a plug shaped and dimensioned to be received within the cavity of the annular body, wherein the plug is removable from the annular body.

25. The cushion as claimed in claim 24, wherein the plug comprises visco-elastic material.