UNITED STATES PATENT APPLICATION

ASSIGNEE

Sealy Technology LLC RELATED APPLICATIONS

There are no pending applications related to this application.

TITLE OF THE INVENTION

VARIABLE COIL DENSITY ANISOTROPIC INNERSPRINGS

FIELD OF THE INVENTION

The present inventioii is in the general field of support structures and systems and, more particularly, flexible support structures which include springs.

BACKGROUND OF THE INVENTION

Spring systems for mattress and other reflexive support structures as used in furniture and seating typically have an array of interconnected springs or other recoil devices which support a reflexive support surface. Internal springs in mattresses ("innersprings") commonly have a plurality of interconnected individual spring units in a matrix with parallel rows and columns. In one of the most common types of mattress innersprings, which can be made by an automated wire-forming process, rows of helical wire springs or "coils" are produced and lined up for insertion into an innerspring assembler which connects adjacent rows of coils by a lacing wire which runs between the rows transverse to a length of the innerspring. The spacing between the coils in each row is uniform, and can be set by adjustment of the innerspring assembler and held in position by the lacing wire. Innersprings of different sizes are made by changing the number of coils in each row and the total number of rows. The coil density and resultant spring rate, support characteristics and feel, such as stiffness and extent of recoil, however is uniform throughout the innerspring where the coils are evenly distributed. Some innersprings also have a larger diameter border wire which is connected to the tops of the coils about a perimeter of the innerspring.

Sleeping mattresses are constructed with a wide variety of materials over and about the innerspring. Some of the materials are provided for enhancing the structural and reflexive properties of the innerspring, including support characteristics at the edges of the innerspring and

mattress. For example, U.S. Patent No. 5,787,532 discloses foam wall structures which fit with the perimeter coils of a mattress innerspring to stiffen the edges of the mattress. Regardless of the amount or different types of materials positioned about the innerspring or even connected to the innerspring, the homogeneous isotropic spring properties and support characteristics of the innerspring as a result of the even spacing and placement of the coils or spring units is not altered.

SUMMARY OF THE INVENTION

The present disclosure is of anisotropic innersprings in which the placement and density of the coils or spring units varies between one or more regions or areas of the innerspring. As used herein, the terms "anisotropic" and "anisotropy" are used with reference to innersprings in the physical meaning, i.e., having unequal physical properties in different areas or zones or regions or in different dimensions. In the context of innersprings, the anisotropy refers to the density of springs or coils and the consequent average spring rate and/or firmness of different regions of the innerspring resulting from the density and arrangement of coils in one or more regions of the innerspring, which differs from the density and arrangement of coils and average spring rate in other regions of the same innerspring. A region of an anisotropic innerspring of the disclosure is defined by groups of a plurality of coils which are positioned relatively at a common spacing or density. The spacing of the coils within the regions is different from region to region, so that the coil density is different from region to region. The padding and upholstery materials which are combined with the innerspring to form a mattress may be selected and arranged according to the density of coils of the region of the innerspring over which the materials are positioned.

Another aspect of the disclosure and invention is an anisotropic innerspring with different numbers of coils in different regions of the innerspring, the innerspring having a plurality of interconnected coils arranged with axes of the coils parallel and ends of the coils located in common respective planes, the innerspring having multiple regions defined by groups of coils with axes of the coils spaced apart at a common distance, including a first region with coil axes spaced at a first distance and a second region with coil axes spaced at a second distance which is greater than the first distance; the coils of the multiple regions of the innerspring being

interconnected by lacing wires which extend between the coils and from one region of the innerspring to another region of the innerspring.

And a further general concept of the disclosure and invention is an innerspring of the type which can be used in a mattress or other flexible support system which has a plurality of interconnected coils arranged with axes of the coils parallel and respective ends of the coils in common planes which define opposed support planes of the innerspring; a first group of coils arranged with axes of the coils of the first group spaced apart at a common first distance, the first group of coils defining a first region of the innerspring; a second group of coils arranged with axes of the coils of the second group spaced apart at a common second distance which is greater than the second fixed distance, the second group of coils defining a second region of the innerspring, whereby a density of coils in the first region is greater than a density of coils in the second region, and a coil density of the first region is greater than a coil density of the second region.

These and other concepts and aspects of the disclosure and the inventions hereof are described in further detail in the following Detailed Description made with reference to the accompanying Drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an embodiment of a variable coil density anisotropic innerspring and an enlargement of an edge region thereof, and

FIG. 2 is an elevation view of a the variable coil density anisotropic innerspring of FIG. l, and

FIGS. 3-12 are plan views of alternate embodiments of variable coil density anisotropic innersprings of the disclosure, each having different patterns, arrangements and zones of coils in the innersprings.

DETAILED DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS

As shown in the Figures, a variable coil density anisotropic innerspring, indicated in its entirety at 10, is assembled with a plurality of springs or coils 20, shown as generally helical form coils with first and second (or upper and lower) ends 21, 22 and a coil body 23, which as

illustrated is in the form of a helix which extends between the coil ends. Other types and shapes of springs or coils may be used in accordance with the principles of the disclosure, which is primarily concerned with the placement and relative placement of springs or coils within an innerspring, and is therefore not limited to any particular type or shape of spring or coil. As used herein, the term "coil" means and includes all forms of springs and coils which can be used in an iraierspring constructed according to the principles of the disclosure.

As shown in FIG. 1 , the innerspring 10 is made up of a plurality of coils 20 arranged in a matrix or array, with coils generally aligned in rows R and columns C ₅ with axes of the coils parallel, and respective ends of the coils in common planes which define planar support or spring surfaces of the innerspring. The number of coils in each row and column is dictated by the overall design size of the innerspring. The innerspring width W is generally determined by the number and spacing of coils in each row R. The innerspring length L is generally determined by the number and spacing of coils in each column C. Although described with reference to width W and length L, such reference is for explanatory purposes only and the relative anisotropic arrangement of the coils is not limited to the exact form shown.

FIG. 1 illustrates an exemplary variable coil density anisotropic innerspring in which the columns CIl — C13 and columns CrI — Cr3, located at respective longitudinal perimeters or perimeter regions of the innerspring 10, are arranged at a lateral spacing between the columns (or between the axes of the coils) less than a lateral spacing between the coils of the remaining columns C. Although illustrated in groupings of three adjacent columns CIl - C13 and CrI - Cr3 which define the longitudinal perimeters or perimeter regions of the innerspring, the disclosure includes other numbers or groupings of columns or rows with spacings different than, i.e. less than or greater than, other numbers or groups of columns or rows of coils within an innerspring, which form groups or regions of coils which are distinct from other groups or regions of coils by the difference in relative spacing between the axes of the coils within a group or region. For a mattress innerspring, the present disclosure provides coil anisotropy by greater coil density, as a result of closer relative spacing between coil axes and columns, in this example along the longitudinal peripheral regions defined by columns CIl - C13 and columns CrI - Cr3. This produces greater rigidity and stiffness along the longitudinal edge region of the mattress which is

desirable for increased edge support, anti-roll-off, and resistance to permanent set resulting from use of the longitudinal edge as a seating surface.

In conventional innersprings, the relative lateral spacing between helical form coils in each row of coils, i.e., the lateral distance between the axes of two adjacent coils or between the outermost radii of two adjacent coils, is commonly measured and set with reference to the coil pitch, which is the linear distance from one convolution of the coil to an adjacent convolution, measured at the outer radius of the coil convolutions and parallel to the longitudinal axis of the coil. A typical uniform coil spacing in an innerspring may be, for example, two pitches, meaning that each coil is laterally spaced from adjacent coils in a row at a distance of one to two times the coil pitch. The coil spacing thus set determines the coil density and overall spring rate of the innerspring. The coil spacing between adjacent rows of coils is generally very close, even to the point of being tangent or with some overlap, as is necessary for the small diameter helical lacing wire to wrap around the adjacent convolutions at the ends of the coils. Thus the lateral spacing of the coils in each row can be adjusted and varied in accordance with the present disclosure, as for example by setting the innerspring assembler spacing. One representative example of lateral spacing of coils in the rows, as shown in FIG. 1, is zero or tangential spacing of the coils in columns CIl - C31 and CIr- C3r, and one to two pitch or more spacing of the remaining coils in each row. The disclosure includes any spacing or variable spacing of any coils or groups of coils in a row, which spacing may or may not be repeated from row to row.

Other non-limiting examples and embodiments include closer coil spacing on one side or end of an innerspring; spacing which gradually or abruptly increases or decreases in the width or length directions of the innerspring or in both the width and length directions; variable spacing which alternates, such as pairs or groups of coils which are closely spaced or tangent with the pairs or groups separated by larger spacings; or different coil spacings from row to row, such as one row wherein the coils are closely spaced or tangent, and another row wherein the coils are at greater spacings. For automated assembly of innersprings of the disclosure, any coil spacing which the innerspring assembler can establish can be used to produce a variable coil density anisotropic innerspring of the disclosure.

The variable coil density anisotropic innersprings of the disclosure can be manufactured with the same total number of coils as in conventional isotropic innersprings of the same overall size, e.g. twin, queen, king, because the conservation of coil spaces in the more dense regions is used in the less dense regions.

Another aspect of the innerspring designs of the disclosure, wherein there are regions of the innerspring with differing coil density as a result of variable lateral spacing in the coil rows R, is that each region by itself may be isotropic so that it provides uniform spring effect and support. The boundary of one region of lesser coil density by a region of greater coil density contributes to torsional rigidity of the innerspring as a whole, laterally or longitudinally. For example, the greater coil density of the regions defined by columns CIl - C31 and CIr- C3r provided mechanical resistance to any tendency of the remaining central region to deflect or compress laterally from lateral or torsional forces on the coils of the central region.

Another aspect of the disclosure, and in particular an aspect of the anisotropic nature of the innersprings of the disclosure, is the gauge of wire which is used to form the coils. The wire gauge may be varied according to the location and density (i.e., spacing) of the coils. For example, coils which are located in areas or regions of greater density, such as the coils in columns CIl - C31 and CIr- C3r, may be made of wire of a different size gauge (smaller or larger) than the wire of the coils in the remaining areas where the coil density is less. For example, the coils of columns CIl — C31 and CIr - C3r if made of heavier gauge wire will produce an innerspring with even greater stiffness in the perimeter regions than if all of the coils of the innerspring are made of the same gauge wire. Related to this design variable is the size and configuration of the coils. For example, the coils located in regions of greater coil density may have a different (greater or smaller) diameter to the coil ends and/or the helical coil body than that of the coils in the regions of lesser coil density. By varying these parameters, the overall spring rates of the various regions of an innerspring can be formed to close specifications. Another non-limiting design example of this aspect of the disclosure is to form the coils located at the perimeter of the innerspring from relatively heavier gauge wire to further contribute to edge support and anti-roll-off characteristics.

FIG. 3 illustrates another embodiment of a variable coil density anisotropic iπnerspring 10 in which coils 20 are arranged in columns C in a repeating pattern of lateral spacing along the width W of the innerspring. The longitudinal edges of the innerspring are formed by the closely adjacent columns C11-C12 and CrI -Cr2 to provide edge support similar to that described with reference to FlG. 1. A central longitudinal region of the innerspring is defined by closely adjacent or tangential coils columns CIn and Cm. The central longitudinal region of relatively greater coil density and consequent spring rate can be enlarged by additional closely adjacent columns of coils. In the areas between the longitudinal peripheral regions and the central longitudinal region the coil density and consequent spring rate is relatively less as a result of the increased lateral spacing of the columns Ci of coils 20. The density of the wire of the coils in columns Ci may be the same or greater as that of the coils in the other columns. Also the overlying materials which make up the mattress may be selected and arranged according to the coil density of the underlying region of the innerspring.

FIG. 4 illustrates a right/left version of an anisotropic variable coil density innerspring 10 of the disclosure, wherein one lateral half or region of the innerspring 10 has a greater density of coils 20 than the other. This type of innerspring is suitable for use in a his/hers type mattress constructed to have distinctly different support characteristics and feel on each lateral half or portion thereof of the sleep surface. As illustrated, the spacing of the columns Cl of coils 20 on the left lateral half or portion thereof of the innerspring may be standard tangential or substantially tangential, and the spacing of the columns Cr of coils 20 on the right lateral half or portion thereof being relatively greater, resulting in lesser coil density and average spring rate. For example, the spacing of coil columns Cr may be one pitch or more greater than the spacing of coil columns Cl. In this embodiment, the spacing or rows R is uniform along the length of the innerspring, but does not necessarily have to be tangential or substantially tangential as shown, but rather with some degree of spacing between the coils of the rows.

FIG. 5 illustrates a head/foot or upper body/lower body version of an anisotropic variable coil density innerspring 10 of the disclosure, wherein one upper or lower body region of the innerspring 10 has a greater density of coils 20 than the other. This type of innerspring is suitable for use in a mattress constructed to have distinctly different support characteristics and feel on upper body or lower body regions of the sleep surface. As illustrated, the spacing of the

rows Ru of coils 20 in an upper region of the innerspring, for example oriented toward the head of the mattress, may be tangentially or substantially tangentially spaced, and the spacing of the rows Rl of coils 20 being relatively greater, resulting in lesser coil density and a lower average spring rate over that region as compared to the region defined by coil rows Ru. For example, the spacing of coil columns Cr may be one pitch or more greater than the spacing of coil columns Cl. The relatively greater spacing of the rows Rl of the coils results in a lesser number of columns Cl than columns Cu, as illustrated by a ratio of 12:16, although other ratios are possible as related to the spacing of rows Rl. hi this embodiment also, the longitudinal spacing or rows Ru and Rl is uniform along the length of the innerspring, but does not necessarily have to be tangential or substantially tangential as shown, but rather with some degree of spacing between the coils of the rows Ru, Rl.

FIG. 6 illustrates an additional alternate embodiment of an anisotropic variable coil density innerspring of the disclosure wherein a central longitudinal region of the innerspring 10, defined by coil columns Cc which are spaced tangentially, provides an area of relatively greater coil density and higher spring rate than that of the bi-lateral regions defined by coil columns Cl. As with the other innerspring configurations, the overlying material which is used to construct a mattress, and particularly the padding layers beneath the upholstery, can be selected and arranged according to the support characteristics and spring rates of the underlying regions of the innerspring, such in this case for example padding of greater density in the bi-lateral regions and/or additional layers to compensate for or work with the lower spring rate of the bi-lateral regions.

FIG. 7 illustrates an alternate embodiment of an anisotropic variable coil density innerspring of the disclosure in which a pattern of coil spacing in each coil row is repeated, and the repeated pattern is out of phase with the next adjacent coil row. For example, beginning with coil row Rl, from right to left, a pattern of three closely or tangentially spaced coils and three spaced apart coils is repeated throughout the row. In the next adjacent row R2, the same pattern is repeated, but beginning at the right with three spaced apart coils. This alternating shaft of the coil spacing pattern is then repeated. The coil density thus varies within each row Rn, and from row to row throughout the entire innerspring.

FIG. 8 illustrates an alternate embodiment of an anisotropic variable coil density iiraerspring 10 of the disclosure in which the spacing rows R of coils of the innerspring gradually increases along the length of the innerspring, the spacing increasing either from the head end to the foot end or vice versa. Though merely exemplary as shown, rows Rl and R2 may be tangential or substantially tangential and repeated as such, or increasing according to pitch, such as one pitch or one-half pitch increase per row or greater. The gradation of the row spacing increase may be linear or non-linear. The spacing of the rows R beyond tangential results in entire rows being devoid of coils. In order to lace the coils together, the lacing wires 21 are run longitudinally to interconnect the coils which are adjacent or tangent in each row.

FIG. 9 illustrates an alternate embodiment of an anisotropic variable coil density innerspring 10 of the disclosure in which the spacing in the rows R and columns C is, with the exception of the end rows Re, non-tangential and preferably with a column intra-coil distance of one or more pitches. The coil spacing in the rows R is at every other column C. The coil spacing in the columns C is out of phase with the adjacent columns so that the coils of adjacent columns are not laterally aligned, with the exception of rows Re. Conversely, the coils of every other column C are laterally aligned. This creates a desirable offset pattern of distributed coil placement which is isotropic throughout a major expanse of the innerspring, and which can include greater density at the ends, rows Re, and/or along the longitudinal sides. Also, although illustrated with the lacing wires 21 in a longitudinal orientation, conventional lateral lacing is also possible where the outer diameters of the laterally adjacent coils are generally aligned.

FIG. 10 illustrates one embodiment of a zoned type anisotropic variable coil density innerspring 10 of the disclosure in which there are multiple (e.g., three) zones or regions Ru, Rl, Ru, of varying densities of coils 20 which are generally longitudinally arranged, for example head-to-foot, to form the anisotropic innerspring 10. One way in which the coil density of the zones or regions Ru, Rl can be made different from other zones or regions is by varying the spacing of the columns C. As with other embodiments of the innerspring 10, the coil spacing within the columns C does not have to be the same in one region such as region Ru at the head of the innerspring, as in another region Ru at the foot of the innerspring.

FIG. 11 illustrates an alternate embodiment of a zoned type anisotropic variable coil density innerspring 10 of the disclosure in which there multiple (e.g., five) zones or regions Ru, Rl, of varying densities of coils 20 which are generally longitudinally arranged, for example head-to-foot to form the anisotropic innerspring 10. As with the embodiment of FIG. 10, one way in which the coil density of the zones or regions Ru, Rl can be made different from other zones or regions is by varying the spacing of the columns C As with the embodiment of FIG. 10, the coil spacing within the columns C does not have to be the same in one region such as region Ru at the head of the innerspring, as in another region Ru at the foot of the innerspring.

FIG. 12 illustrates a further alternate embodiment of a zoned type anisotropic variable coil density innerspring 10 of the disclosure in which there multiple (e.g., seven) zones or regions Ru, Rl, of varying densities of coils 20 which are generally longitudinally arranged, for example head-to-foot to form the anisotropic innerspring 10. As with the embodiment of FIGS. 10 and 11, one way in which the coil density of the zones or regions Ru, Rl can be made different from other zones or regions is by varying the spacing of the columns C. As with the embodiments of FIGS. 10 and 11, the coil spacing within the columns C does not have to be the same in one region such as region Ru at the head of the innerspring, as in another region Ru at the foot of the innerspring. The zones or regions of the embodiments of FIGS. 10-12 and the other embodiments may be aligned or registered with overlying and/or underlying layers of material which are positioned with the innerspring to form a mattress.

The foregoing descriptions are of representative embodiments of the principles and concepts of the disclosure which encompass and include other types of anisotropic innersprings with variable coil densities.