Patent Application
20050039264
The present invention pertains generally to mattresses and mattress innersprings and; more particularly, to mattresses which include both wire-form innersprings and structural foam components.
Foam components are commonly combined with wire or steel form innersprings in mattress, seating and other flexible support structures. Early versions included foam layers which were either attached directly to a wire innerspring or simply held in position by overlying upholstery. Smaller foam components are designed to fit within spaces of the innerspring. As described in the referenced related application, a new approach to the integration of innersprings and foam components involves welding or bonding of mating foam components to form a unibody structure which fits with an innerspring, forming a unitized steel and foam structure which provides flexible support.
Different types of foam and foam parts have been used extensively in seating and bedding as flexible support material. Semi-rigid open and closed cell foams of polyethylene, polyurethane or polystyrene have been used in combination with other components and load-bearing structures, such as wire form innersprings and framing to form flexible supports, such as described in U.S. Pat. Nos. 5,048,167; 5,469,590; 5,467,488 and 5,537,699 and 5,787,532. In most of these spring support products, the foam pieces surround or interfit with spring elements, and rely on mechanical connection with the spring elements to keep the foam pieces in place. Foam pieces have also been adhesively bonded and combined with innersprings. The types of foams used in these applications are typically open-cell polyurethane and latex materials, which can be effectively bonded by compatible adhesives. The open-cell structure of these types of foams results in easier compression or lower ILD which is suitable for many bedding and seating applications, particularly for support surface or topper layers underneath upholstery. They are not generally utilized as structural members in a mattress or support cushion in seating. Also, polyurethane and other non-thermoplastic type foams cannot be bonded or welded by any heat-source process due to their decomposition properties.
Some foam shapes have been used integrally with springs to augment or otherwise support metal spring structures, as shown for example in U.S. Pat. Nos. 5,133,116; 5,239,715; 5,467,488 and 5,687,439. Because this type of use of foam relies on the surrounding metal structure to hold it in place, the foam itself is not in the form of a unitized three-dimensional support structure with its own load-bearing capacity.
Another use of foam in connection with an innerspring is disclosed in U.S. Pat. No. 5,787,532, wherein an extruded foam piece is used as a perimeter wall to an innerspring, with fingers which mechanically engage the coils of the innerspring. While this provides vertical support at the perimeter of the innerspring, it relies on mechanical attachment to the innerspring for the correct orientation. It also only provides support primarily in the vertical direction and does nothing to stabilize the innerspring in the lateral or horizontal directions.
One type of foam which has been used for these types of applications is closed-cell polyethylene foam which is molded or extruded by known processes into desired shapes. Closed-cell foam has greater support properties due to the fact that each closed cell contains a gas which maintains the cells in an inflated state when under compression, as compared to open-cell foams from which a substantial volume of air is displaced when compressed.
Latex and polyethylene foam is commonly used in slab form as cushioning or dampening layers in mattresses and seating, held in place relative to an innerspring simply by surrounding upholstery. Alternatively, latex foam can be readily molded, and has been molded about innersprings to form a foam-encased mattress. This type of combination of foam and innerspring does not include any internal foam components which provide three-dimensional flexible, or which are bonded to any other components of a mattress or other flexible support device.
The present invention provides a multiple component mattress or support structure which combines integrated foam materials and structures with an innerspring or other flexible core. An extruded polyolefin foam deck is used as an underlying flexible structural support and dampening foundation for an innerspring. An insulator pad, such as a thermally bonded, high-density, high quality polyester fiber pad is positioned over an opposing side of the innerspring opposite the foam deck. A foam encasement, such as a molded polymerizing reaction mixture, structurally integrates the foam deck, innerspring and insulator pad by bonding to perimeter areas of the foam deck and insulator pad, and to perimeter coils or spring elements of the innerspring, creating a fully integrated unibody assembly. The foam encasement forms an exterior wall about the perimeter of the innerspring and foam deck and structurally integrates these components. A sculpted foam topper is then positioned over the insulator pad on a support surface of the innerspring opposite the foam deck, preferably with surface design features sculpted in the support side of the topper. The further combination of the foam topper, by adhesive bonding to the insulator pad, the three different foam structures of the foam deck, foam encasement and foam topper, and a flexible core such as the innerspring or solid block of foam, creates a highly variable and tunable support system.
A foam deck which can be used in accordance with the invention is preferably a structural extruded foam, such as closed-cell polyolefin, which may be thermally bonded to form the described three-dimensional deck structures as described in the related application, incorporated herein by reference. In a preferred embodiment, the foam deck is formed by a plurality of extruded foam beams which are bonded or fused together by welds along abutting edges. The foam is preferably thermoplastic in behavior, being able to reversibly melt and solidify without decomposing. In one embodiment of the invention, a thermally bonded unitized three-dimensional foam structure is combined with another support element, such as an innerspring, to provide a flexible support structure which is at least partially encapsulated in foam, such as polyurethane foam or other resilient polymer molded about a perimeter of the foam deck and innerspring. The thermoplastic foam structure of the foam deck dampens and softens the feel of the innerspring, and provides edge support and stability, and a protective cover for the underside of the innerspring. It also provides a foundational slab to which walls of the foam encasement attaches. In a preferred embodiment, the thermoplastic foam components or pieces are made of extruded foam, such as gas-blown polyethylene, in a box beam or slab form. The vertical profile of the box beams of the foam deck defines a degree of stiffness and flexure which responds to localized loads on the overlying innerspring. The foam encapsulation of the innerspring and foam deck forms side walls to the mattress which are structurally integrated with the foam deck, innerspring and insulator pad opposite the foam deck. The side walls provide vertical support, and form a smooth unitized body ideally configured for neat application of upholstery. The use of a foam topper in combination with the foam encased innerspring increases the support density of the edge areas of the mattress, and allows for customization of the comfort profile by sculpting of the primary support surface.
These and other preferred and alternate features and advantages of the present invention are described herein with reference to the accompanying Figures which illustrate a representative physical form of the inventive concepts.
In the Figures:
With reference to
Although illustrated with this type of wire form interconnected innerspring, the invention is equally applicable to all types of innersprings and innerspring assemblies, regardless of the form of the individual coils and the manner of interconnection of the coils, and including such variants as Marshall type pocketed coils and coils made of materials other than steel spring wire. The invention is also highly adaptable for use with other types of reflexive bodies or flexible cores which may be used in place of traditional innersprings having individual coils or spring elements. Some examples of other types of innersprings which may be used in combination with the unitized foam structures include: wire-form innersprings of any variety such as Bonnel or other helical designs, continuous wire-form designs which do not have individual helical coils, interconnected springs or coils made of plastic or composite materials, pocketed or Marshall-type coils held in an array by material which is sewn or bonded, and solid blocks of material such as latex foam or other suitable foams or layers of foam (referred to herein as a “flexible core”) shown as block 190 in
One form of an internal foam component used with the invention is in the form of a foam deck, indicated generally at 200, which is positioned adjacent to the innerspring 110, for example underlying or proximate to support surface 112. The foam deck 200 is preferably formed of extruded foam box beams 202 of the type illustrated in the cross-sectional views of
The foam deck 200 also serves as the structural and protective base of a one-sided mattress, as illustrated in
To produce a box beam twin-panel version of the foam deck, multiple segments of box beams 202 can be bonded or fused together to form a major support surface 204 or a slab which is trimmed or cut to form a platform of the desired dimensions, which preferably corresponds to the innerspring 110. This type of construction of a foam deck 200 is shown in
The foam deck 200 performs several functions, including serving as a foundation or base for the innerspring 110 particularly when constructed as a one-sided mattress, providing dimensional stability to the innerspring in both the x and y directions (parallel to the surface) and providing a platform for formation of foam encasement about the innerspring, as further described. Use of the foam deck 200 underneath the innerspring 110 is advantageous over the conventional construction of one-sided mattresses which simply cover the bottom surface of the innerspring with a thin layer of material, leaving the underside of the innerspring unsupported and unprotected. The underlying foam deck 200 provides a soft, flexible foundation to the innerspring, and increases the overall height of the mattress without requiring any additional height to the innerspring.
As shown in
A foam encasement 600 is provided to structurally integrate the components of the foam deck 200, innerspring 10 and pad 180. In the embodiments shown in
To fully structurally integrate the foam encased innerspring of the invention, the foam encasement 600 also bonds or otherwise makes contact with the insulator pad 180, at least on an underside 181, and additionally at the edges 182 and partially extending over a top surface of insulator pad 180 as shown. This accurately secures the pad 180 in position on the support surface of the innerspring 110 without the use of any fasteners or other attachment device. It also keeps the insulator pad 180 in tight overlying arrangement with the innerspring so that the pad acts in unison with the innerspring and the foam deck foundation.
The exterior foam wall 610 of the foam encasement 600 forms a smooth and uniform wall to the entire integrated structure, over which padding and/or upholstery can be placed in a very smooth and tight manner to provide the mattress or support device with a highly finished appearance. This is particularly advantageous over other mattress designs which have no substructure at the perimeter other than coils over which upholstery is applied. The walls of the foam encasement 600 provide substantial vertical support at the perimeter of the mattress, effectively maximizing the useable surface area of the mattress.
A preferred method of forming the foam encasement 600 is by molding, preferably with a polymer foam reaction mixture in a fluid state, which can be injected into a mold in which the foam deck 200, innerspring 110 or flexible core and insulator pad 180 are placed in the described arrangement. In practice, for example, the three main components of the foam deck 200, innerspring 110 and foam topper 700 are aligned and placed in a mold which defines the exterior wall 610. The polymer foam reaction mixture is then introduced into the mold cavity and around the perimeter of the assembly, contacting the various components as described, and curing by polymeric reaction into the foam encased integrated structure. Other methods of formation of the foam encasement 600 can be employed, and the invention is not limited to any particular method or manner of combination of the described components.
With the integrated support structure thus formed, a foam topper 700 is placed on top of pad 180, and is preferably bonded thereto by a thermoplastic adhesive. Alternatively, the foam topper 700 can be placed in the described mold with the underlying insulator pad 180, innerspring 110 or flexible core and foam deck 200, and the foam encasement 600 formed or molded to bond the foam topper 700 to the other components by contact with the underside or sides of the foam topper 700.
In a preferred form, foam topper 700 is a sculpted foam topper with a sculpted or textured surface features 710 arranged over a primary support surface, and side rails 720 along the longitudinal sides of the topper, or ends, or about the entire perimeter. The foam topper 700 can be made of polyurethane or latex foam material of any suitable density. Machine processing or water or laser cutting can be used to form any design of surface features 710, such as for example the six-sided tapered towers shown. The density of the foam topper 700 can be selected to produce a mattress or support device of any desired feel or support characteristic. The density may be selected with consideration of the stiffness of the innerspring, and the amount of dampening provided by the underlying foam deck. As a single unibody piece of foam, the topper 700 has the physical characteristics of a single type of foam with homogeneous foam cell structure, with the differing surface topographies altering the aggregate density and ultimate support characteristics of the zones defined by the sculpted area and rails. The sculpting of the support side of foam topper 700 is done by the removal of foam material in a pattern, such as the depicted matrix of valleys or voids with corresponding projections. The projections extend generally from the bottom of the valleys or voids so that it is the top or tip of the projections which collectively form a contoured support surface, over which an upholstery layer is laid. The solid form perimeter or rail sections provide a higher level of firmness than the contoured surface. Whereas a topper of uniform surface contour and density tends to become excessively compressed at the edge, which effectively reduces the usable sleeping area of a mattress, the density edge or rail zones maximize the support area of the mattress all the way to the edge of the encapsulated innerspring. As an alternative to a central sculpted zone with perimeter, laterally extending zones with varying topography can be formed to create a combination of varying support zones. The topography of the support surface of the foam topper 600 may also be formed to have gradual transitions between areas of differing topographies and corresponding densities. For example, in the case of a zone with a surface topography having multiple projections, which merges with a generally flat topography, the projections of the first zone can be made to decrease in height or depth as they approach the flat second zone, so that the transition in firmness is less perceptible when felt through the upholstery layers. In this same manner, multiple zones of differing density can be made in a single layer, with graduated transitions between the zones, so that the transitions from one foam density to another foam density are less perceptible through the overlying upholstery.
Variations of the three primary support components; foam deck 200, innerspring 110 and foam topper 700, provide a wide range of design combinations to produce mattresses or support structures with widely varying comfort profiles of feel and performance.
As described in the related application, additional components can be thermally bonded with the foam deck 200 to form a unitized foam structure with additional foam pieces located at lateral edges of the innerspring 110, and which are thermally bonded or welded to the support surface 204 of foam deck 200. In these embodiments, the foam encasement 600 can still be utilized by application over the described additional foam components. Other foam components of various configurations can be attached to the major support surface of the foam deck 200 for contouring or structural strength as desired.
Different designs of innersprings and coils, including coils with different terminal configurations, such as the coils described in U.S. Pat. No. 5,713,088, with terminal convolutions of coils 120 in support contact with the upper surface 210 of foam deck 200, can be used in alternate embodiments of the invention.
Other foam components which interface with the coils of the innerspring can be used in conjunction with the foam deck 200 and/or foam encasement 600, such as foam pillars which are positioned within the coil bodies and extending generally perpendicular from the underlying or overlying foam decks 200, adding stiffness and support at desired locations, and working in cooperation with the foam topper 700.
The mattress 100 can of course be upholstered with material layer or layers 500, or quilted layers, which may include an underlayment of a padding and/or non-woven, and an outer upholstered material, which may be foam-backed, and closed with tape edges 510. The mattress can be made into virtually any upholstered mattress structure that is common to the art. The rigidity of the foam encasement provides the ideal form for the upholstery material 500, with smooth flat surfaces and well-defined comers over which the material can be pulled taut and secured. The well-defined corners of the edges of the foam encasement and foam topper provide an ideal guide and support for the overlying tape edges 510, resulting in very straight tape edges which gives the mattress a highly finished appearance.
This application is related to a Provisional U.S. patent application of the same title filed on Oct. 15, 2003, and is a continuation-in-part of U.S. application Ser. No. 10/402,612, entitled UNITIZED THERMOPLASTIC FOAM STRUCTURES, filed on Mar. 28,2003.
| Number | Date | Country | |
|---|---|---|---|
| 60511849 | Oct 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10402612 | Mar 2003 | US |
| Child | 10686823 | Oct 2003 | US |
