One-sided mattress construction

Information

  • Patent Grant
  • 6243900
  • Patent Number
    6,243,900
  • Date Filed
    Thursday, January 13, 2000
    24 years ago
  • Date Issued
    Tuesday, June 12, 2001
    23 years ago
Abstract
A one-sided mattress assembly includes a core of pocketed coil springs having a layer of resiliently compressible material covering the upper surface thereof and having a bottom surface constructed of a substantially rigid material without a compressible layer. The core of coil springs is preferably attached to the bottom surface only around its periphery. By such a construction the amount of compressible padding is reduced by one-half and consequently the mattress is capable of exhibiting a substantial reduction in the amount of permanent deflection in use. Maintenance of the mattress such as by rotating or turning the mattress over is also avoided.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates generally to mattress assemblies and, more particularly, to one-sided mattress assemblies that offer significant reduction in the amount of permanent deflection resulting from the compaction of padding materials under normally encountered loads.




2. Description of the Related Art




A conventional inner spring mattress as known in the bedding industry generally comprises a resilient construction consisting of two sleep surfaces (top and bottom) enclosing an assembly of wire springs. The springs are typically covered over with padding on the top and bottom surfaces and the whole assembly is encased within a ticking, often quilted, that is sewn closed around its periphery to a border or boxing. For many years one preferred form of spring assembly construction has been known as Marshall construction. In Marshall construction individual wire coils are each encapsulated in fabric pockets and attached together in strings which are arranged to form a closely packed array of coils in the general size of the mattress. Examples of such construction are disclosed in U.S. Pat. No. 685,160, U.S. Pat. No. 4,234,983, U.S. Pat. No. 4,234,984, U.S. Pat. No. 4,439,977, U.S. Pat. No. 4,451,946, U.S. Pat. No. 4,523,344, U.S. Pat. No. 4,578,834, U.S. Pat. No. 5,016,305 and U.S. Pat. No. 5,621,935, the disclosures of which are incorporated herein by reference in their entireties.




Conventionally, inner spring mattresses have identical top and bottom surfaces. During normal life of such conventional mattresses some degree of permanent deflection, or sag, can develop in the mattress surfaces due to compaction of the component padding materials. This permanent deflection can interfere with the mattresses' intended function of providing a supportive and resilient sleep surface. Inner spring mattress manufacturers recommend periodically rotating and turning over the mattress utilizing the top and bottom sleep surfaces in order to counteract, minimize and/or delay the aforementioned permanent deflection. Under continued use, this compaction becomes more permanent. The degree of permanent deflection is directly related to the type and amount of padding installed both over and under the wire spring assembly. To remedy this shortcoming, manufacturers utilize materials that produce less permanent compaction. These materials are generally more dense, but can be less comfortable and more expensive.




Accordingly, it is desirable to provide an inner spring mattress assembly which exhibits a reduced amount of permanent deflection due to compaction of padding materials while at the same time exhibiting substantial comfort in use. It is further desirable to provide such a mattress assembly that can be constructed by conventional known manufacturing techniques. Still further, it is desirable to provide such a mattress assembly that is cost-effective to produce.




SUMMARY OF THE INVENTION




The present invention improves over the prior art by providing a one-sided mattress assembly including a core of pocketed coil springs having a layer of resiliently compressible material covering the upper surface thereof and having a bottom surface constructed of a substantially rigid material without a compressible layer. The core of coil springs is preferably attached to the bottom surface only around its periphery. By such a construction the amount of compressible padding is reduced by one-half and consequently the mattress is capable of exhibiting a substantial reduction in the amount of permanent deflection in use. Maintenance of the mattress such as by rotating or turning the mattress over is also avoided.











BRIEF DESCRIPTION OF THE DRAWINGS




The foregoing and other novel features and advantages of the invention will be better understood upon a reading of the following detailed description taken in conjunction with the accompanying drawings wherein





FIG. 1

is an exploded cross-sectional view of a conventional two-sided inner spring mattress construction;





FIG. 2

is an exploded cross-sectional view of a one-sided inner spring mattress constructed according to the principles of the invention;





FIG. 3

is a schematic plan view of a complete assembly of Marshall coils for use in the mattress construction according to the present invention as illustrated in

FIG. 2

; and





FIG. 4

is a partial perspective view, partly broken away, of the Marshall coil assembly illustrated in FIG.


3


.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




Referring now to the drawings, and initially to

FIG. 1

, a conventional two-sided mattress is illustrated in exploded cross-section and designated generally by the reference numeral


10


. The mattress includes as a principal component an assembly of Marshall spring coils


12


, as will be described in detail hereinafter and which comprises the central core of the mattress


10


. The mattress has an upper sleep surface


14


and a lower sleep surface


16


and, therefore, is of a conventional type intended to be turned over periodically to help minimize compression of its padding material. The padding material, which is preferably identical on both sides


14


and


16


includes a layer of closed-cell foam


18


such as made of polyurethane. Covering the foam layer is a ticking layer


20


which may be quilted with additional foam in a manner well-known in the art. The ticking layers


20


are fastened such as by sewing to a border


22


which extends around the entire periphery of the core of coil springs


12


.




Turning now to

FIG. 2

, a mattress constructed according to the invention is shown in exploded cross-section and designated by the reference numeral


30


. This mattress, like the conventional mattress


10


illustrated in

FIG. 1

preferably has a central core


12


of Marshall coils on which an upper sleep surface


34


is formed with a layer of foam padding


18


and a cover layer of ticking


20


. However, in accordance with the invention, the mattress


30


has an underside


36


which comprises a substantially rigid layer of material


38


covered by a thin layer


40


preferably of a non-woven sheeting. A border


42


connects the ticking


20


and sheeting layer


40


and extends around the periphery of the coil assembly


12


. A lower border wire


44


is secured to the coil assembly


12


around its periphery as well as to the layer


38


such as by hog rings


46


.





FIGS. 3 and 4

illustrate the preferred form of mattress core


12


of the aforementioned Marshall coil construction. In this construction, closely positioned coil springs are aligned in a string assembly


50


(

FIG. 4

) wherein individual springs


52


are each encapsulated within a pocket


54


of fabric material


56


which may be sewn or ultrasonically welded to create the pockets


54


and to create a unitary Marshall coil type assembly


12


. An example of such construction is more fully disclosed in U.S. Pat. No. 5,621,935 which is commonly assigned herewith and the disclosure of which is incorporated herein by reference in its entirety.




It can now be appreciated that a one-sided inner spring mattress


30


constructed according to the invention offers considerable advantages over prior art conventional two-sided mattresses in terms of reducing the amount of permanent deflection of the sleeping surface due to undesirable compaction of padding materials. Because the mattress


30


essentially has a 50 percent reduction in padding due to bottom rigid layer


38


, the coil assembly


12


does not settle into and compact a lower padding layer as would happen with a two-sided mattress of conventional construction having identical padding layers on both sides.




In one preferred form the relatively rigid bottom layer


38


is formed of high density polyurethane foam having a weight of approximately 1.85 lbs/cu. ft. The foam layer


38


also preferably has a firmness in a range of between 45 and 60 ILD, where “ILD” stands for Indented Load Deflection. In practice an ILD of 55 has proved to be most effective.




It can also be appreciated that the one-sided mattress


30


of the invention offers the significant advantage of completely eliminating maintenance of the mattress by periodically turning it over as is recommended for conventional two-sided mattresses. Accordingly, it is more convenient for the consumer to use. Further, with the Marshall coil construction and use of conventional materials, the mattress


30


may be readily manufactured by techniques that are well-known in the industry and thus can be produced in a cost-effective manner.




While the present invention has been described in connection with preferred embodiments thereof, it will be apparent to those skilled in the art that many changes and modifications can be made without departing from the true sprit and scope of the present invention. Accordingly, it is intended by the appended claims to cover all such changes and modifications as come within the scope of the invention.



Claims
  • 1. A one-sided inner spring mattress assembly comprising:a central core of individual fabric pocketed coil springs arranged in a Marshall coil type assembly; an upper assembly padding layer extending over a top surface of said core; a lower relatively rigid layer underlying said core; wherein said lower layer is resistant to compression by the central core of pocketed springs and comprises a. high density polyurethane foam having a weight of about 1.85 lbs per cubic foot and a firmness in the range of about 45 ILD to about 60 ILD.
  • 2. The mattress assembly of claim 1 wherein the core is surrounded by a lower border wire and is secured to said lower layer only by attaching said border wire to said lower layer.
  • 3. The mattress assembly of claim 1 wherein said lower layer is covered by a thin sheet of non-woven material.
  • 4. The mattress assembly of claim 1 including an upper quilt layer of ticking material.
  • 5. A one-sided inner spring mattress assembly comprising:a central core of closely positioned individual pocketed coil springs surrounded at a bottom edge by and connected to a border wire; an upper padding layer overlying the central core; and a bottom relatively rigid layer underlying the core; wherein said border wire is attached to said bottom layer to hold said bottom layer to said core.
  • 6. The mattress assembly of claim 5 wherein said lower layer comprises high density foam.
  • 7. The mattress assembly of claim 5 wherein said lower layer has a weight of about 1.85 lbs per cubic foot.
  • 8. The mattress assembly of claim 5 wherein said lower layer has a firmness in the range of about 45 ILD to 60 ILD.
  • 9. The mattress assembly of claim 5 wherein said lower layer is constructed of high density polyurethane foam.
  • 10. The mattress assembly of claim 5 wherein said lower layer is covered by a thin sheet of non-woven material.
  • 11. The mattress assembly of claim 5 wherein said upper padding layer is covered by a quilt layer.
  • 12. An innerspring mattress comprising:a core of individual springs each pocketed in fabric and arranged together to define a unitary spring assembly; a border wire positioned adjacent a bottom edge of said core and extending around the periphery of said core, said border wire being connected to said spring assembly; a layer of relatively incompressible material underlying said spring assembly, wherein said layer is connected only to said border wire to attach said layer to said spring assembly.
  • 13. The mattress of claim 12 wherein said layer is formed of high density polyurethane foam.
  • 14. The mattress of claim 12 wherein said layer has a weight of about 1.85 lbs per cubic foot.
  • 15. The mattress of claim 12 wherein said layer has a firmness in the range of about 45 ILD to 60 ILD.
  • 16. The mattress of claim 12 wherein said layer is covered by a thin sheet of non-woven material.
  • 17. A one-sided inner spring mattress assembly comprising;a central core of closely positioned individual coil springs surrounded at a bottom edge by and connected to a border wire; an upper padding layer overlying the central core; and a bottom relatively rigid layer underlying the core; wherein said border wire is attached to said bottom layer to hold said bottom layer to said core.
  • 18. The mattress assembly of claim 17 wherein said lower layer comprises high density foam.
  • 19. The mattress assembly of claim 17 wherein said lower layer has a weight of about 1.85 lbs per cubic foot.
  • 20. The mattress assembly of claim 17 wherein said lower layer has a firmness in the range of about 45 ILD to 60 ILD.
  • 21. The mattress assembly of claim 17 wherein said lower layer is constructed of high density polyurethane foam.
  • 22. The mattress assembly of claim 17 wherein said lower layer is covered by a thin sheet of non-woven material.
  • 23. The mattress assembly of claim 17 wherein said upper padding layer is covered by a quilt layer.
US Referenced Citations (13)
Number Name Date Kind
685160 Marshall Oct 1901
1321095 Genge Nov 1919
1459540 Labenz Jun 1923
3031690 Ramsay May 1962
4234983 Stumpf Nov 1980
4234984 Stumpf Nov 1980
4439977 Stumpf Apr 1984
4451946 Stumpf Jun 1984
4523344 Stumpf Jun 1985
4578834 Stumpf Apr 1986
5016305 Suenens et al. May 1991
5621935 St. Clair Apr 1997
5787532 Langer et al. Aug 1998