WO2011072022A1

WO2011072022A1 - Renewable mattress

Info

Publication number: WO2011072022A1
Application number: PCT/US2010/059479
Authority: WO
Inventors: John K. Roma
Original assignee: Otis Bed Manufacturing Company, Inc.
Priority date: 2009-12-08
Filing date: 2010-12-08
Publication date: 2011-06-16

Abstract

A pillowtop mattress comprises a base mattress and a renewable pillowtop removably attached to the base mattress portion The base mattress includes a marshall coil assembly enclosed by a foam frame, which is encased in a stretchable fabpc cover having hook-and-loop patches on its upwardly facing surface at locations that do not correspond with the shoulders or hips of the user The pillowtop includes a resilient core surrounded by a fire retardant barrier, and a cover of stretchable and launderable fabpc having a zippered panel through which the resilient core and fire barner are removably received The pillowtop cover has a plurality of hook-and-loop patches registering with the hook-and-loop patches on the base mattress cover for removably attaching the pillowtop to the base mattress The pillowtop may be renewed by detaching it from the base mattress, laundering the pillowtop cover, and replacing the spent resilient core with a new one.

Description

RENEWABLE MATTRESS

FIELD OF THE INVENTION

[0001] The present invention is relates generally to mattresses, and more particularly to renewable mattresses and so-called "piUowtop" mattresses. BACKGROUND OF THE INVENTION

[0002] The mattress design referred to in the industry as a piUowtop mattress has an additional cushion or piUowtop attached to a base mattress to provide extra cushioning. To emphasize the pillow look of the mattress, the piUowtop is attached to the base mattress inboard of the edge or side border of the base mattress, giving the mattress a true "piUowtop" look. By attaching the piUowtop in this manner, the side of the mattress has an area of indention, where the bottom face of the piUowtop projects over the base mattress. The joint between the base mattress and the piUowtop is typically covered with a fabric gusset. Coil springs within the base mattress provide support for the user, while a foam layer in the piUowtop cushions the user.

[0003] As may be understood, the metal support coils have a useful lifetime that is significantly longer than the useful lifetime of the piUowtop foam layer. The foam in the piUowtop will loose its ability to provide sufficient cushioning even though the coils continue to provide good support. Consequently, despite the fact that the base mattress portion is in fine working condition, the overall piUowtop mattress becomes uncomfortable and is typically replaced by an entirely new mattress.

[0004] Most, if not all, piUowtop constructions in conventional piUowtop mattresses utilize "quilting." Quilted material usually requires a light weight fabric that does not stretch, known as "quilt backing," to carry the various layers efficiently through the quilting machine (quilting can be made with a stretchable layer of quilt backing, but this cuts production efficiency dramatically). Conventional piUowtop constructions also include a firm fabric panel over the coils of the base mattress. However, the non- stretchable quilt backing and fabric panel diminish the role of the coils in providing comfortable support, and the piUowtop portion must play a larger role in providing comfort. As a result, the foam layer of the piUowtop is subjected to greater loading during use, and its useful life is shortened relative to the life of the underlying coils.

[0005] Pursuant to current safety regulations, bedding must be flame resistant. Non-stretch fire barrier layers used in conventional pillowtop mattresses diminish the support function of the base mattress coils in a manner similar to the non-stretch quilt backing and fabric panel. As a result, non-stretch fire barriers also contribute to shortened pillowtop life.

[0006] Other conventional mattresses components - such as the mattress surface, the innerspring or support unit, or other support materials and structures - are also vulnerable to deterioration and failure. Due to wear and tear, components of a mattress may sag, shift, or lose form over time. These components do not necessarily wear at the same rate. As mentioned previously, foam has a shorter life span than other components, for example a coil-spring. However, the deterioration of just one component of a mattress may make a mattress uncomfortable, even though the remaining components are in perfect condition. Due to the unified structure of current conventional mattresses and pillowtop mattresses, worn components cannot be replaced individually.

SUMMARY OF THE INVENTION

[0007] The present invention provides a pillowtop mattress wherein a pillowtop portion detaches from a base mattress portion and can be completely renewed.

[0008] The base mattress includes a marshall coil assembly enclosed by a foam frame, which in turn is encased in a stretchable fabric cover. The base mattress cover includes hook-and-loop (VELCRO®) patches on its upwardly facing surface at locations that do not correspond with the shoulders or hips of the user.

[0009] The pillowtop includes a resilient core surrounded by a fire retardant envelope or barrier, and a cover of stretchable and optionally launderable fabric having a zippered panel through which the resilient core and associated fire retardant envelope are removably received. The pillowtop cover has a plurality of hook-and- loop patches on its downwardly facing surface at locations registering with the hook- and-loop patches on the base mattress cover for removably attaching the pillowtop to the base mattress. [0010] The design provides a longer lifetime for the resilient core of the pillowtop. Moreover, when the resilient core of the pillowtop loses substantial resiliency, the pillowtop may be renewed by detaching it from the base mattress, laundering the pillowtop cover, and replacing the spent resilient core with a new resilient core.

[0011] A second embodiment of the present invention provides for a renewable mattress wherein internal mattress components can be individually removed and renewed.

[0012] The renewable mattress is made up of several detachable components, including a fabric shell including a bottom and a plurality of peripheral walls that define a shell interior. Affixed to each of the peripheral walls is at least one fabric compartment. Each fabric compartment has at least one foam insert that can be removably received by the fabric compartment(s). Further, a support unit is removably received by the shell interior and is bounded by the compartmented foam inserts. Further, a padded topper is arranged above the at least one compartmented foam insert and the support unit. The topper is removably attached to the fabric shell and the fabric compartments. Lastly, a top cover, which is at least partially separable from the peripheral walls of the fabric shell, is attached to the peripheral walls of the fabric shell to enclose the at least one compartmented foam insert, the support unit, and the topper.

[0013] The design provides a longer lifetime of a mattress. Specifically, detachable mattress components allow for worn components to be replaced with new components, and to be laundered from time to time.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the drawings:

[0015] Fig. 1 is a perspective view of a renewable pillowtop mattress formed in accordance with an embodiment of the present invention, wherein a pillowtop portion is shown lifted from a base mattress portion;

[0016] Fig. 2 is a longitudinal cross-sectional view of the renewable pillowtop mattress shown in Fig. 1; [0017] Fig. 3 is a transverse cross-sectional view of the renewable pillowtop mattress shown in Fig. 1;

[0018] Fig. 4 is a perspective view of a renewable mattress formed in accordance with another embodiment of the present invention;

[0019] Fig. 5 is an exploded perspective view of the renewable mattress shown in Fig. 4;

[0020] Fig. 6 is a partial sectional view of the renewable mattress shown in Fig. 4;

[0021] Fig. 7 is a bottom plan view of the renewable mattress shown in Fig. 4;

[0022] Fig. 8 is an end elevational view of the renewable mattress shown in Fig. 4;

[0023] Fig. 9 is a side elevational view of the renewable mattress shown in Fig. 4;

[0024] Fig. 10 is a perspective view of the renewable mattress, partially exploded to show an underside of a padded topper of the renewable mattress;

[0025] Fig. 11 is a perspective view showing a corner portion of the renewable mattress in detail, wherein the topper and a fabric cover of the mattress are removed for sake of visibility of internal components; and

[0026] Fig. 12 is a perspective view showing a corner portion of the renewable mattress with the fabric cover partially separated from a main fabric shell of the mattress.

DETAILED DESCRIPTION OF THE INVENTION

[0027] Figs. 1-3 show a renewable pillowtop mattress 10 formed in accordance with an embodiment of the present invention. Mattress 10 generally comprises a base mattress 12 and a pillowtop 14 removably attached to base mattress 12.

[0028] Base mattress 12 includes a marshall coil assembly 16, a foam frame 18 enclosing marshall coil assembly 16, and a base mattress cover 20 surrounding the foam frame and the coil assembly. Marshall coil assembly 16 is of conventional construction and includes a plurality of metal coils 22 disposed within respective pockets of a fabric encasement 24. Alternatively, there may also be a welded frame of flat wire fastened to the underside of marshall coil assembly 16 for stability purposes. [0029] Foam frame 18 includes a foam base layer 26, a pair of opposed foam side walls 28 and a pair of opposed foam end walls 30 adhered to base layer 26, and a foam top layer 32 adhered to side walls 28 and end walls 30 such that foam frame 18 defines a hollow core for receiving coil assembly 16. It is advantageous to use extra- firm foam, such as 2.1 pound density, 55 ILD (Indentation Load Deflection) foam, so that base mattress returns to its original size after being rolled and vacuum-sealed for shipping. By way of non-limiting example, base layer 26 may be 2" (5.08 cm) thick; side walls 28 and end walls may be 4" (10.16 cm) thick by 6" (15.24 cm) high; and top layer 32 may be 1.5" (3.81 cm) thick convoluted foam. The constituent parts of foam frame 18 may be fixed to one another using a water-based adhesive.

[0030] Fabric encasement 24 of marshall coil assembly 16 may be adhered to the top (inner) surface of foam base layer 26 and to the bottom (inner) surface of foam top layer 32 using a water-based adhesive. The surfaces that are being fastened together with adhesive need to be coated evenly and completely; water based adhesive should not be applied excessively as glue may "pool" and form hard spots(these spots may not be immediately noticeable, but may become noticeable over time).

[0031] Base mattress cover 20 may be made from a stretchable fabric, for example Body Climate by Polartec, available from Tietex Corporation, to minimize interference with the support action of coil assembly 16. Base mattress cover 20 includes a plurality of hook-and-loop (e.g. VELCRO®) patches 21 fixed to an upwardly facing surface of cover 20 for removable attachment of pillowtop 14. Base mattress 12 may be hand-tufted, given that its thickness exceeds the capacity of standard automatic tufting machines.

[0032] Pillowtop 14 includes a resilient core 34, a stretchable fire retardant envelope 36 around resilient core 34, and a fabric pillowtop cover 38 surrounding resilient core 34 and envelope 36. Resilient core 34 is preferably a foamed latex rubber, such as 21 or 28 ILD Talalay Latex available from Latex International in Ansonia, CT, but another resilient material may be used. Resilient core 34 may be any desired thickness. It is contemplated to provide a selection of embodiments using various thicknesses for resilient core 34. For example, a selection of pillowtops wherein the resilient core 34 is 2" (5.08 cm), 3" (7.62 cm), or 4" (10.16 cm) in thickness may be provided. It is further contemplated to form resilient core 34 as a multi-layer composite of different materials. Multi-layer composites can be in various thicknesses, and be made by laminating varying firmness together, for instance a 3" (7.62 cm) thick core can be made from using a 1" thick layer of soft foam (15 ILD) between two 1" (2.54 cm) thick layers of firm (35 ILD) foam, or vice-versa.

[0033] Envelope 36 around resilient core 34 is made of one or more layers, including at least one layer of a stretchable knitted fire retardant fabric, such as C395 available from Milliken Corporation of Spartanburg, South Carolina. The

construction of envelope 36 will depend upon the material used for resilient core 34. Where a highly flammable material is used, such as latex rubber, a multi-layer envelope may be required to meet government safety standards. Where a less flammable material is used, such as polyurethane foam, a single-layer envelope may be sufficient to meet government safety standards. Again, stretchable fabric is advantageous to minimize interference with the support function of the underlying marshall coil assembly 16, thereby reducing the occurrence of pressure points.

[0034] Fabric pillowtop cover 38 is formed of a stretchable fabric that may also be launderable. Currently, Silene II from Creative Ticking in Gastonia, North Carolina is preferred as fabric for making pillowtop cover 38, however other fabrics may be substituted without straying from the invention. Pillowtop cover 38 includes a zippered panel 40 releasably connected to the remained of the pillowtop cover 38 by a zipper 42 such that pillowtop cover 38 may be opened to an extent allowing resilient core 34 and fire retardant envelope 36 to be removed and replaced with a new resilient core and fire retardant envelope. Zipper 42 may extend completely around the periphery of panel 40, or around a portion of the periphery of panel 40. For aesthetic reasons, panel 40 and zipper 42 are preferably provided on a downwardly facing surface of pillowtop cover 38, such that zipper 42 is offset from the outside edge of the pillowtop cover and is not visible when mattress 10 is in its assembled state ready for use. Because the actual zipper teeth are set on strips of non-stretch fabric coupled to the stretchable fabric of pillowtop cover 32, it is preferable to provide a slightly oversized length of zipper 42, represented in Fig. 1 by the wavy appearance of zipper 42, in order to prevent inconsistency in the support and cushioning characteristics of mattress 10 which might result in an annoying feel to the user above zipper 42. [0035] Pillowtop cover 38 further includes a plurality of hook-and-loop (i.e. VELCRO®) patches 39 fixed to a downwardly facing surface of pillowtop cover 38 and arranged to register with patches 21 on base mattress cover 20 to removably attach pillowtop 14 to base mattress 12. Patches 21 and 39 may be located away from areas directly under the shoulders or hips of a user, so that lack of uniformity is less likely to be noticed by the user. In one arrangement, loop "landing target" patches 21 on the base mattress cover 20 are at least 2" (5.08 cm) wider and longer than the corresponding hook patches 39 on the underside of pillowtop cover 38. This is to reduce the fastening strength, so that when the pillowtop is removed, the fabric covers will not be damaged. The larger size of the loop landing target also prevents the hook target from "hooking" the outer base mattress fabric and damaging it. In a preferred arrangement, patches 21 on the base mattress cover 20 are hook patches and patches 39 on the pillowtop cover 38 are loop patches to allow for increased launderability of the pillowtop cover 38.

[0036] As may be understood from the foregoing description, pillowtop 14 is completely renewable without need to replace base mattress 12. Pillowtop 14 may be detached from base mattress 12, panel 40 may be unzipped and opened to allow removal of a spent resilient core 34 and fire retardant envelope 36, and the empty pillowtop cover 38 may be laundered if the fabric is launderable. A completely new resilient core 34 having a new or reconditioned fire retardant envelope 36 may be inserted into laundered pillowtop cover 38 through opened panel 40, which may then be zipped closed. The renewed pillowtop 14 may then be reattached to base mattress 12 using patches 21 and 39. It is also conceivable to possess more multiple piUowtops having different cushioning characteristics, and to change piUowtops based on the desired cushioning characteristic.

[0037] The mattress of the present invention also allows the load of a user's weight to be shared more evenly between the pillowtop core and the coil springs, thereby extending the cushioning life of the pillowtop.

[0038] Figs. 4-12 depict a renewable mattress 50 having removable internal components in accordance with a second embodiment of the present invention.

[0039] A perspective view of assembled renewable mattress 50 is shown in Fig. 4 and an exploded view of mattress 50 is shown in Fig. 5. Renewable mattress 50 generally comprises a fabric shell 52 and a top cover 54, which are at least partially separable from one another to allow access to removable internal mattress

components as described below. The top cover may be separable from the fabric shell 52 via a zipper 55. Fig. 12 depicts top cover 54 partially unzipped from fabric shell 52 via zipper 55. Fabric shell 52 includes a bottom 52A and a plurality of peripheral walls 52B defining a shell interior 53. Zipper 55 may extend completely or almost completely around the periphery of top cover 54 and fabric shell 52. If zipper 55 does not extend completely around the periphery, then a relatively short segment of cover 54 may be permanently sewn to a peripheral wall 52B of fabric shell 52 and the remaining periphery of cover 54 may be connected to walls 52B by zipper 53. Fabric shell 52 further includes a plurality of fabric flaps affixed to an upper portion of peripheral walls 52B, wherein each flap 52C has a fastener element 52D affixed thereto facing shell interior 53. Fabric shell 52 may also include an outwardly projecting lip 52E around the perimeter of the fabric shell 52, more particularly around an upper exterior portion of shell walls 52B. Fabric shell 52 may be a decorative fabric laminated to a 0.8 ounce per square foot of fire retardant rayon material. The current preferred material for the fabric shell 52 is Panda Suede, style number 436548, from Milliken Corporation of Spartanburg, South Carolina. Top cover 54 may be a filled stretch knit highloft decorative fabric, with about 3/8 to a 1/2 inch thickness. Currently, CT0085 sold by Beverly Knits, Inc. of Gastonia, NC is the preferred material for the top cover 54.

[0040] Fig. 5 is an exploded view showing the various components of the renewable mattress 50. In the illustrated embodiment, four fabric compartments 56 are arranged in shell interior 53 and affixed to bottom 52A and peripheral walls 52B by stitching 57. Although the embodiment depicted in Figs. 4-12 includes four fabric compartments 56, it is contemplated that a different number of fabric compartments may be used, including a single fabric compartment that extends around the entire border of fabric shell 52. Each fabric compartment 56 includes a zipper 56A for opening and closing the compartment, thereby enabling each compartment 56 to removably receive a foam insert 58. Each fabric compartment 56 may also include a fastener element 56B affixed to an upwardly facing surface of the compartment for use in removably attaching a padded topper 62 over the compartments as described below.

[0041] For safety purposes, it is preferable for each foam insert 58 to be enclosed by fire retardant material 59. However, instead of or in addition to foam inserts 58 being enclosed by fire retardant material, the fabric compartments 56 may be made of fire retardant material, or fire retardant material may be affixed to the fabric compartments 56. The foam inserts 58 may be made of extra-firm foam, such as 2.1 pound density, 55 ILD (Indentation Load Deflection) foam, to provide a supportive framework for mattress 50.

[0042] Renewable mattress 50 further comprises a support unit 60 arranged to fit centrally in shell interior 53 within space defined by surrounding fabric compartments 56 and inserts 58. As depicted in Fig. 11, support unit 60 may be the same height as fabric compartments 56 such that the support unit 60 and fabric compartments 56 form a substantially planar surface to support padded topper 62. Support unit 60 comprises a resilient support core 60A, for example one or more pieces of foam and/or foamed latex rubber, or a coil- spring support such as a conventional marshall coil assembly, and an envelope 60B of stretchable fire retardant material surrounding support core 60A. It is further contemplated to form resilient core 60A as a multilayer composite of different materials. Multi-layer composites can be made by laminating layers of varying firmness together, for instance a layer of soft foam (15 ILD) may be arranged between two layers of firm (35 ILD) foam, or vice-versa.

[0043] Padded topper 62 is constructed to rest on top of the fabric compartments 56 and the support unit 60 below top cover 54. Padded topper 62 includes a resilient core 62A, and a stretchable fire retardant envelope 62B around resilient core 62A. Fig. 6 is a cross-section cutout of the assembled renewable mattress 50 where the interrelation of the top cover 54, fabric compartments 56, support unit 60, and padded topper 62 may be seen. As best seen in Fig. 10, an underside of padded topper 62 includes a plurality of downwardly facing fastener elements 62C affixed to envelope 62B for mating with upwardly facing fastener elements 56B on fabric compartments 56. A top side of padded topper 62 includes a plurality of upwardly facing fastener elements 62D affixed to envelope 62B for mating with fastener elements 52D on flaps 52C on fabric shell 52 when flaps 52C are wrapped around the side edges of padded topper 62. While the illustrated embodiment includes four flaps 52C on fabric shell 52, any number of flaps 52C may be used, including one continuous flap that surrounds the periphery of fabric shell 52. It is also contemplated that fastener elements 62C and 62D may alternatively be attached to a flexible fastener attachment piece 62E. Flexible fastener attachment pieces 62E may wrap around the edges of padded topper 62 and affixed to envelope 62B by gluing, stitching, or tufting.

Additionally, it is contemplated that attachment piece 62E may instead be affixed to or through resilient core 62A by stitching or tufting.

[0044] The various fastener elements 52D, 56B, 62C, and 62D may be, for example, a strip of hook or loop material (e.g. VELCRO® material) for mating with a corresponding loop or hook material, as the case may be. Other types of fastener elements are possible, including without limitation adhesive fastener elements, snap fastener elements, strap elements, and/or clip elements. The fastener elements may be formed of a fire retardant material and may be affixed in place by gluing, stitching, or tufting.

[0045] An assembled renewable mattress 50 may be dissembled by first unzipping the fabric shell 52 from the top cover 54 via zipper 55 to reveal the top of padded topper 62. Next, fabric shell 52 should be unfastened from padded topper 62 by unfastening fastener elements 62D from 52D. Padded topper 62 may then be unfastened and removed from fabric compartments 56 by unfastening fastener elements 62C from 56B. Following the removal of the padded topper 62, the support unit 60 may be removed. Once the padded topper 62 is detached, foam inserts 58 may be removed from the fabric compartments 56 by unzipping zipper 56A. By repetition of the foregoing steps in the reverse order, the renewable mattress 50 may be reassembled.

[0046] Modifications and other embodiments of the invention set forth herein will be apparent to one skilled in the art to which the invention pertains in light of teachings presented in the present specification. Therefore, the invention is not to be limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included. PARTS LIST

[0047] 10 Renewable pillowtop mattress

[0048] 12 Base mattress

[0049] 14 Pillowtop

[0050] 16 Marshall coil assembly

[0051] 18 Foam frame

[0052] 20 Base mattress cover

[0053] 21 Hook-and-loop patches on base mattress cover 20

[0054] 22 Metal coils

[0055] 24 Fabric encasement

[0056] 26 Base layer of foam frame 18

[0057] 28 Side walls of foam frame 18

[0058] 30 End walls of foam frame 18

[0059] 32 Top layer of foam frame 18

[0060] 34 Resilient core

[0061] 36 Fire retardant envelope

[0062] 38 Pillowtop cover

[0063] 39 Hook-and-loop patches on pillowtop cover 38

[0064] 40 Panel in pillowtop cover 38

[0065] 42 Panel zipper

[0066] 50 Renewable mattress

[0067] 52 Fabric shell

[0068] 52A Fabric shell bottom

[0069] 52B Fabric shell walls

[0070] 52C Fabric shell flap

[0071] 52D Fabric shell fastener

[0072] 52E Outwardly projecting lip

[0073] 53 Interior space of fabric shell

[0074] 54 Top cover

[0075] 55 Zipper

[0076] 56 Fabric compartment

[0077] 56A Fabric compartment zipper [0078] 56B Fabric compartment fastener

[0079] 57 Stitching

[0080] 58 Foam insert

[0081] 59 Fire retardant envelope

[0082] 60 Support unit

[0083] 60A Support core

[0084] 60B Fire retardant envelope

[0085] 62 Padded topper

[0086] 62A Resilient core

[0087] 62B Fire retardant envelope

[0088] 62C Downwardly facing fastener

[0089] 62D Upwardly facing fastener

[0090] 62E Flexible fastener attachment piece

Claims

WHAT IS CLAIMED IS:

1. A renewable mattress, comprising:

a fabric shell including a bottom and a plurality of peripheral walls defining a shell interior;

at least one fabric compartment arranged in the shell interior and affixed to the peripheral walls of the shell;

at least one foam insert removably received by the at least one fabric compartment;

a support unit removably received by the shell interior and bounded by the compartmented foam inserts;

a padded topper arranged above the at least one compartmented foam insert and the support unit, the topper being removably attached to the fabric shell; and

a top cover attached to the peripheral walls of the fabric shell and cooperating with the fabric shell to enclose the at least one compartmented foam insert, the support unit, and the topper, wherein the top cover is at least partially separable from the peripheral walls of the fabric shell.

2. The renewable mattress of claim 1, wherein the at least one fabric

compartment comprises a plurality of fabric compartments, and the at least one foam insert comprises a plurality of foam inserts respectively received by the plurality of fabric compartments.

3. The renewable mattress of claim 2, wherein each of the fabric compartments has a zipper to open and close the fabric compartment.

The renewable mattress of claim 2, wherein each of the fabric compartments includes an upwardly facing fastener element and the padded topper includes a plurality of downwardly facing fastener elements arranged to mate with the upwardly facing fastener elements on the fabric compartments for detachably securing the removable topper to the fabric compartments.

The renewable mattress of claim 4, wherein the peripheral walls of the fabric shell include one or more flaps each having a fastener element thereon, and the padded topper includes a plurality of upwardly facing fastener elements arranged to mate with the fastener elements on the flaps for detachably securing the removable topper to the fabric shell.

The renewable mattress of claim 1, wherein the top cover is attached to the peripheral walls of the fabric shell by a zipper.

The renewable mattress of claim 4, wherein the fastener elements arranged to mate with one another are hook and loop fastener elements.

The renewable mattress of claim 5, wherein the fastener elements arranged to mate with one another are hook and loop fastener elements..

The renewable mattress of claim 1, wherein the renewable mattress comprises four fabric compartments.

The renewable mattress of claim 1, wherein the removable topper includes an outer cover of fire retardant material.

The renewable mattress of claim 1, wherein the fabric compartments are formed of fire retardant material.

12. The renewable mattress of claim 1, wherein the removable support unit

includes an outer encasement of fire retardant material.

13. The renewable mattress of claim 1, wherein the peripheral walls include an outwardly projecting lip around the entire fabric shell.

14. The renewable mattress of claim 1, wherein the support unit comprises at least one foam cushion.

15. The renewable mattress of claim 1, wherein the top cover is fully separable from the peripheral walls of the fabric shell.

16. A renewable mattress comprising:

a base mattress including a foam frame, a coil assembly enclosed by the foam frame, and a cover made of stretchable fabric surrounding the foam frame; and

a pillowtop including a resilient core, a fire retardant envelope enclosing the resilient core, and a pillowtop cover surrounding the fire retardant envelope;

wherein the pillowtop is removably attached to the base mattress.

17. The renewable mattress of claim 16, wherein the pillowtop comprises one or more downwardly facing fasteners and the base mattress comprises one or more upwardly facing fasteners to mate with the downwardly facing fasteners for removably attaching the pillowtop to the base mattress.

18. The renewable mattress of claim 17, wherein the pillowtop comprises a

periphery and a longitudinal axis that bisects the pillowtop and the base comprises a periphery and a longitudinal axis that bisects the base; wherein the downwardly facing fasteners are affixed between the periphery of the pillowtop and the longitudinal axis that bisects the pillowtop and the upwardly facing fasteners are affixed between the periphery of the base and the longitudinal axis that bisects the base The renewable mattress of claim 16, wherein the piUowtop cover comprises zippered panel such that the zippered panel may be unzipped to allow the piUowtop cover to be removed from the fire retardant envelope.

The renewable mattress of claim 20, wherein the piUowtop cover comprises material adjacent to the zippered panel and the zippered panel comprises a zipper having a length, the zipper length being oversized relative to the material adjacent to the zippered panel.