Spring cores including variable height springs

Abstract

A spring core includes a first support zone and a second support zone. The first support zone includes primary coil springs arranged in a matrix and interstitial coil springs positioned between adjacent primary coil springs. The second support zone also includes primary coil springs arranged in a matrix and interstitial coil springs positioned there between. The height of the interstitial coil springs of the first support zone differs from the height of the primary coil springs of the first support zone such that the first support zone has a first support characteristic, and the height of the interstitial coil springs of the second support zone differs from the height of the primary coil springs of the second support zone by a second distance different than the first distance such that the second support zone has a second support characteristic different than the first support characteristic.

Description

SPRING CORES INCLUDING VARIABLE HEIGHT SPRINGSRELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Application Serial No. 63 / 562,569, filed March 7, 2024, the entire disclosure of which is incorporated herein by this reference.TECHNICAL FIELD

[0002] The present invention relates to spring cores including springs having at least two different heights. In particular, the present invention relates to spring cores that include primary coil springs and interstitial coil springs that have different heights.BACKGROUND

[0003] Spring cores are typically made of either a plurality of coil springs interconnected into a single unit or pocketed coil springs, which are also known as wrapped coils, encased coils, encased springs, or Marshall coils. Pocketed coil springs are generally recognized as providing a unique feel to a mattress when used in a spring core because each discrete coil is capable of moving independently to support the body of a user, or a portion thereof, resting on the mattress. In particular, in pocket coil spring assemblies, each coil is wrapped in a fabric pocket and moves substantially independently of the other coils in the pocket coil spring assembly to thereby provide individualized comfort and contouring to the body of a user. Moreover, as a result of moving substantially independently from one another, the pocket coils also do not directly transfer motion from one pocket coil to another, such that the movement of one user resting on amattress assembly using pocket coils will not disturb another user resting on the mattress assembly. In this regard, mattress assemblies constructed with pocketed coil springs are generally recognized as providing a soft and luxurious feel, and are often more desirable than a traditional interconnected coil spring mattress. Accordingly, a spring core that includes pocketed coil spring assemblies and further improves upon the support and feel provided by traditional pocketed coil spring assemblies would be both highly desirable and beneficial.SUMMARY

[0004] The present invention relates to spring cores including springs having at least two different heights. In particular, the present invention relates to spring cores that include primary coil springs and interstitial coil springs that have different heights.

[0005] In one exemplary embodiment of the present invention, a spring core of a mattress is provided which includes a first support zone and a second support zone. The first support zone includes a plurality of primary coil springs arranged in a matrix with each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end. The first support zone further includes a plurality of interstitial coil springs positioned between adjacent primary coil springs with each of the interstitial coil springs having an upper end and a lower end with an uncompressed height of the interstitial coil defined between the upper end and the lower end. The second support zone includes a plurality of primary coil springs arranged in a matrix with each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end. The second support zone further includes a plurality of interstitial coil springs positioned between adjacent primary coil springs with each of the interstitial coil springs having an upper end and a lower end with an uncompressed height ofthe interstitial coil defined between the upper end and the lower end. In the exemplary spring core, the height of the plurality of interstitial coil springs of the first support zone differs from the height of the plurality of primary coil springs of the first support zone by a first distance such that the first support zone has a first support characteristic, and the height of the plurality of interstitial coil springs of the second support zone differs from the height of the plurality of primary coil springs of the second support zone by a second distance different than the first distance such that the second support zone has a second support characteristic different than the first support characteristic.

[0006] According to some exemplary embodiments, the first distance is zero such that the height of the plurality of interstitial coil springs of the first support zone is the same as the height of the plurality of primary coil springs of the first support zone.

[0007] According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs.

[0008] According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, the plurality of primary coil springs are arranged in a square grid and each of the plurality of interstitial coil springs is positioned between four adjacent primary coil springs.

[0009] According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, the height of the plurality of interstitial coil springs is less than the height of the plurality of primary coil springs.

[0010] According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, the height of the plurality of interstitial coil springs is greater than the height of the plurality of primary coil springs.|0011] According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, the lower end of each of the plurality of interstitial coil springs is substantially planar with the lower end of each of the plurality of primary coil springs.[0012| According to some exemplary embodiments, for either the first support zone, the second support zone, or both the first and second support zones, the lower end of each of the plurality of interstitial coil springs defines a plane that is not the same as a plane defined by the lower end of each of the plurality of primary coil springs.

[0013] According to some exemplary embodiments, the spring core can be characterized as including a foot portion, a head portion, and a middle portion positioned between the foot portion and the head portion. According to these embodiments, the first support zone comprises the foot portion, the head portion, or both the foot portion and the head portion, and the second support zone comprises the middle portion.

[0014] According to some exemplary embodiments, the first support zone and the second support zone comprise multiple alternating zones.

[0015] According to some exemplary embodiments, the spring core can be characterized as including a central portion and a peripheral portion extending around the central portion. According to these embodiments, the first support zone comprises the central portion, and the second support zone comprises the peripheral portion.

[0016] According to some exemplary embodiments, the spring core can be characterized as including a torso support portion and a leg support portion. According to these embodiments, the second support zone comprises the torso support portion and the leg support portion.|0017] According to some exemplary embodiments, the spring core can be characterized as including a left side portion and a right side portion. According to these embodiments, the first support zone comprises the left side portion, and the second support zone comprises the right side portion.[0018| In another exemplary embodiment of the present invention, a spring core of a mattress is provided that also comprises a first support zone and a second support zone. The first support zone in this embodiment, however, includes only a plurality of primary coil springs arranged in a matrix, where each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end. The second support zone then includes a plurality of primary coil springs arranged in a matrix and a plurality of interstitial coil springs positioned between adjacent primary coil springs. In this embodiment, the height of the plurality of interstitial coil springs of the second support zone differs from the height of the plurality of primary coil springs of the second support zone by a first distance to provide the second support zone with a support characteristic that is different from that found in the first support zone, which does not include the interstitial coil springs. In some embodiments of such a spring core, a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs of the second support zone, a height of the plurality of interstitial coil springs is less than the height of the plurality of primary coil springs of the second support zone, and / or a height of the plurality of interstitial coil springs is greater than the height of the plurality of primary coil springs of the second supportzone. In some embodiments, the second support zone extends along a longitudinal edge of the spring core.[0019J Further provided, in some exemplary embodiments, are spring cores for a support cushion that include a plurality of primary coil springs arranged in a matrix. Each of the primary coil springs again has an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end. The spring core then further includes a plurality of interstitial coil springs positioned between at least some of the adjacent primary coil springs, with each of the interstitial coil springs having an upper end and a lower end and with an uncompressed height of the interstitial coil defined between the upper end and the lower end. In such embodiments, each of the interstitial coil springs has a height greater than or less than the height of the plurality of primary coil springs of the second support zone. In some such embodiments, a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs.

[0020] Further features and advantages of the present invention will become evident to those of ordinary skill in the art after a study of the description, figures, and non-limiting examples in this document.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. l is a schematic side view of a first exemplary configuration of a plurality of primary coil springs and a plurality of interstitial coil springs made in accordance with the present invention;

[0022] FIG. 2 is a schematic side view of a second exemplary configuration of a plurality of primary coil springs and a plurality of interstitial coil springs made in accordance with the present invention;

[0023] FIG. 3 is a schematic side view of a third exemplary configuration of a plurality of primary coil springs and a plurality of interstitial coil springs made in accordance with the present invention;|0024] FIG. 4 is a schematic side view of a fourth exemplary configuration of a plurality of primary coil springs and a plurality of interstitial coil springs made in accordance with the present invention;

[0025] FIG. 5 is a schematic top view of an exemplary spring core made in accordance with the present invention;

[0026] FIG. 6 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0027] FIG. 7 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0028] FIG. 8 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0029] FIG. 9 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0030] FIG. 10 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0031] FIGS. 11 A-l IF are schematic top views of further exemplary spring cores made in accordance with the present invention;

[0032] FIGS. 12A-12C are schematic top views of further exemplary spring cores made in accordance with the present invention;

[0033] FIG. 13 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0034] FIG. 14 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0035] FIG. 15 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0036] FIG. 16 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0037] FIG. 17 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0038] FIG. 18 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0039] FIG. 19 is a schematic top view of another exemplary spring core made in accordance with the present invention;

[0040] FIG. 20 is a schematic top view of another exemplary spring core made in accordance with the present invention; and

[0041] FIG. 21 is a graph showing the transition of an amount of support provided by a spring core made in accordance with the present invention as a function of the location on the spring core.DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0042] The present invention includes spring cores including springs having at least two different heights. In particular, the present invention relates to spring cores that include primary coil springs and interstitial coil springs that have different heights.

[0043] Referring first to FIG. 5, in one exemplary embodiment, a spring core 100 is provided which includes a plurality of primary coil springs 110 arranged in a matrix and with a plurality of interstitial coil springs 210 positioned between the primary coil springs 110. In this exemplary embodiment, the plurality of primary coil springs 110 are arranged in a square grid in which the primary coil springs 110 are positioned in regular rows and columns. As such, there is a space defined between four adjacent primary coil springs 110 in which an interstitial coil spring 210 is positioned. While the exemplary spring core 100 includes an interstitial coil spring 210 in each of these spaces, it is contemplated that in some other embodiments, one or more spaces may not be filled, as discussed further below.

[0044] With respect to the primary coil springs 110, and referring now back to FIG. 1, in the exemplary spring core 100, each primary coil spring 110 includes a wire 120 forming a plurality of helical convolutions which collectively define a substantially cylindrical shape, and a flexible enclosure 130, or pocket, encasing the wire 120.

[0045] With further respect to the wire 120 of the primary coil springs 110, in a typical coil spring formed with a helically-spiraling continuous wire, the spring constant and resultant feel of the coil spring are primarily determined by the wire gauge (or wire diameter), the total number of convolutions in the coil spring, the pitch between the convolutions of the coil spring, and the size of the convolutions (coil diameter). In this regard, the pitch (or vertical spacing) between each convolution of the coil spring is typically controlled by the rate at which the continuous wire, which forms the coil spring, is drawn through a forming die in a coil-forming machine. Once formed, a larger pitch will typically produce a stiffer coil spring due to the increased vertical orientation of the wire, while a smaller pitch will typically produce a softer coil spring and allow for a larger number of total convolutions in the coil body. Similarly, larger diameterconvolutions in a coil spring also contribute to a lower spring constant and consequentially softer feel. Of course, because the wire forming the coil spring is continuous there is no clearly defined beginning point or ending point of any single convolution. Furthermore, the diameter and pitch is typically adjusted gradually between one portion of the spring to another. As such, oftentimes a single convolution of the coil spring does not, in fact, have just one single diameter or just one single pitch, but may include, for example, a beginning or end portion with a variable diameter and / or pitch that transitions to the adjacent convolution. Therefore, as used herein, the diameter and pitch of a convolution will typically refer to an average diameter and pitch, but can also, in some embodiments, be inclusive of or refer to a maximum diameter and pitch or a minimum diameter and pitch.

[0046] In the exemplary primary coil spring 110 shown in FIG. 1, the continuous wire 120 ranges from about 10 gauge to about 20 gauge and in some particular embodiments about 13.75 gauge to about 17 gauge. Furthermore, the continuous wire 120 has a tensile strength of between about 200 kpsi to about 400 kpsi and in some particular embodiments between about 270 kpsi to about 320 kpsi. However, these ranges are merely exemplary and should not be considered limiting.

[0047] With respect to the diameters and pitches of the helical convolutions formed by the continuous wire 120 of the primary coil spring 110, each of the helical convolutions has a diameter that are all substantially equal to one another. Specifically, in the exemplary primary coil spring 110, the helical convolutions have a diameter of about 69 mm but in other embodiments, the coil diameters can range from about 60 mm to about 80 mm. The continuous wire 120 also defines a pitch between each of the helical convolutions, where each of the pitches are substantially equal to one another and, in the exemplary primary coil spring 110, is about 74mm, but in other embodiments, the pitch can range from about 5 mm to about 80 mm, such as about 50 mm.[0048J Similar to the primary coil springs 110, and referring still to FIG. 1, in the exemplary spring core 100, each interstitial coil spring 210 is made of a wire 220 forming a plurality of helical convolutions which collectively define a substantially cylindrical shape, and a flexible enclosure 230 encasing the wire 220.

[0049] Specifically, in the exemplary interstitial coil spring 210, the helical convolutions have a diameter of about 40.5 mm, but, in other embodiments, the coil diameter can be about 30 mm, or within a range from about 10 mm to about 50 mm. The interstitial coil springs 210 typically have a diameter smaller than the diameter of the primary coil springs 110 so as to fit in the spaces defined between adjacent primary coil springs 110, as discussed further below. Other characteristics of the wire 220 of the interstitial coil spring 210 (i.e., wire gauge, number of convolutions, and / or pitch between convolutions), however, may be substantially the same as the wire 120 of the primary coil spring 110 or, alternatively, one or more of the characteristics of the wire 220 of the interstitial coil spring 210 may differ from the wire 120 of the primary coil spring 110.

[0050] With further respect to the flexible enclosures 130, 230, in the exemplary coil spring 110, the flexible enclosures 130, 230 are preferably made of a material, such as a fabric, which can joined or welded together by heat and pressure (e.g., via ultrasonic welding or similar thermal welding procedure). For example, suitable fabrics may include one of various thermoplastic fibers known in the art, such as non-woven polymer-based fabric, non-woven polypropylene material, or non-woven polyester material. Alternatively, the flexible enclosures may be joined together by stitching, metal staples, or other suitable methods. In short, a widevariety of fabrics or similar sheet material may be used to make and join together the flexible enclosures as would be recognized by those skilled in the art.[0051J The details provided above for the primary coil springs 110 and interstitial coil springs 210 are merely exemplary, however, and a wide variety of coil springs can be used in accordance with the present invention. For example, rather than a cylindrically shaped coil spring, any number of various coil spring shapes may be utilized including, but not limited to, stovepipe, hourglass, conical, funnel, and barrel shapes as well as a coil-in-coil spring, in which the inner coil and / or the outer coil or even a portion thereof (i.e., an uppermost portion, a middle portion, or a lowermost portion) include stovepipe, hourglass, conical, funnel, and barrel shapes. For example, in some embodiments, the primary or interstitial coil springs can include the springs described in International Patent Application Publication No. WO 2025 / 030133, which is incorporated herein by reference in its entirety. Non-helical springs and / or springs made of materials other than wire are also possible without departing from the spirit and scope of the present invention.

[0052] Referring still to FIG. 1, in this particular embodiment, the primary coil springs 110 generally have an upper end 112 and a lower end 114 and an uncompressed height, Hi, defined between the upper end 112 and the lower end 114. Similarly, the interstitial coil springs 210 have an upper end 212 and a lower end 214 and an uncompressed height, H2, defined between the upper end 212 and the lower end 214. The height, Hi, of the primary coil springs 110 is about 203 mm while the height, H2, of the interstitial coil springs 210 is about 200 mm. As such, in this exemplary embodiment, the height, H2, of the interstitial coil springs 210 is less than then height, Hi, of the primary coil springs. In some embodiments, the height of the primary coil springs can vary from about 100 mm to about 260 mm and likewise the height of the interstitial coil springscan vary from about 98 mm to about 260 mm. Of note, these exemplary heights are of the assembled coil springs 110, 210 with the wires 120, 220 already positioned within the respective flexible enclosures 130, 230. In some embodiments, the wires 120, 220 are partially compressed when inserted into the flexible enclosures 130, 230 such that the out-of-pocket heights of the wires 120, 220 may be greater than the heights of the coil springs 110, 210. In some particular embodiments, the out-of-pocket height of the wire in the primary coil springs can vary from about 125 mm to about 330 mm and in some more specific embodiments from about 220 mm to about 280 mm. The out-of-pocket height of the wire in the interstitial coil springs can vary from about 100 mm to about 330 mm and in some more specific embodiments from about 205 mm to about 275 mm. In some embodiments, the primary coil springs are about 15 mm taller than the interstitial coil springs. However, and as discussed further below, the primary coil springs are not in all instances taller than the interstitial coil springs and can in some embodiments be about 15 mm shorter than the interstitial coil springs.

[0053] In the exemplary embodiment shown in FIG. 1, the lower ends 214 of the interstitial coil springs 210 are substantially planar with the lower ends 114 of the primary coil springs 110. As the height, H2, of the interstitial coil springs 210 is less than then height, Hi, of the primary coil springs, there is a distance Di between the upper ends 212 of the interstitial coil springs 210 and the upper ends 112 of the primary coil springs 110 which is the difference between the height, Hi, of the primary coil springs 110, and the height, H2, of the interstitial coil springs 210. This advantageously provides a non-linear response when a user lays on the spring core 100.[0054| More specifically, and now with reference to FIG. 1 and FIG. 5, when the primary coil springs 110 and interstitial coil springs 210 are uncompressed, as shown in FIG. 1 (i.e., when the spring core 100 is uncompressed), the upper ends 112 of the primary coil springs 110are located above the upper ends 212 of the interstitial coil springs 210. As such, when a user lays down on the spring core 100, the primary coil springs 110 will initially be the only springs engaged. Specifically, as the spring core 100 is compressed up to the distance Di, only the primary coils springs 110 will compress over the distance Di until the compressed height of the primary coil springs 110 is the same as the uncompressed height, H2, of the interstitial coil springs 210. At that point, the upper ends 112 of the primary coil springs 110 are substantially planar with the upper ends 212 of the interstitial coil springs 210. During further compression of the spring core 100 beyond the distance Di, both the primary coil springs 110 and interstitial coil springs 210 compress simultaneously.

[0055] As the spring core 100 compresses from the uncompressed state to the first predetermined compression distance Di, only primary coil springs 110 compress and, as such, the response of the spring core 100 is related to an initial spring constant Ki based on only the primary coil springs 110. Then, as the spring core 100 is compressed beyond the first predetermined compression distance Di, both the primary coil springs 110 and the interstitial coil springs 210 are compressed together. Accordingly, for compression distances beyond the first predetermined compression distance Di, the response of the spring core 100 is related to a second spring constant K2 based on both the primary coil springs 110 and the interstitial coil springs 210. The term “spring constant” as use herein is not limited to a typical linear response characteristic as, in some embodiments, the primary coil springs and / or the interstitial coil springs are configured to have a non-linear response to compression. Regardless, as the spring constant increases (e.g., from Ki to K2), the spring core 100 becomes “harder.” Thus, the spring core 100 of the present invention provides a variable and non-linear response to loading due to the different activation points of different coils. It should of course be appreciated though thatthe above description is a simplified explanation of one embodiment as the engagement and compression characteristics of the primary coil springs 110 and interstitial coil springs 210 adjacent coils will also depend, in part, on how the primary coil springs 110 and interstitial coil springs 210 are connected, as discussed further below. According to one particular embodiment, the primary coil springs are preloaded to about 1.0 Ibf with spring rates of between about 0.3 Ibf to about 1.0 Ibf depending on where the measurement is taken in the coil. The interstitial coil springs are likewise preloaded to about 0.10 Ibf with spring rates of between 0.2 Ibf to about 1.0 Ibf.

[0056] Referring once again to FIG. 5, as previously mentioned, the interstitial coil springs 210 are positioned in a space defined between adjacent primary coil springs 110, and the interstitial coil springs 210 typically have a diameter that is smaller than the diameter of the primary coil springs so as to fit in these spaces defined between adjacent primary coil springs. This results in an overall increase in coil count within a given area of the spring core 100. According to some exemplary spring cores, load deflection in a given area with the interstitial springs will see an increase of at least 5% as compared to a comparable area without interstitial springs. Furthermore, in combination with the different activation points between the primary coil springs 110 and interstitial coil springs 210 discussed above, the increased spring unit density is achieved without creating excessive initial unit firmness common with high density spring cores.

[0057] Along these lines, it is also appreciated that the relative heights, Hi and H2, of the primary coil springs 110 and interstitial coil springs 210 shown in FIG. 1 are merely one way to achieve the desired variable response from different activation points.

[0058] Referring now to FIG. 2 though, in another exemplary embodiment, a plurality of primary springs 310 are provided which are substantially the same as the primary coil springs110 described above with respect to FIG. 1. A plurality of interstitial springs 410 are also provided which are similar to the interstitial coil springs 210 described above with respect to FIG. 1 except that in the embodiment shown in FIG. 2, the uncompressed height, H4, of the interstitial coil springs 410 is greater than the uncompressed height, H3, of the primary coil springs 310. Similar to FIG. 1, in the exemplary embodiment shown in FIG. 2, the lower ends 414 of the interstitial coil springs 410 are substantially planar with the lower ends 314 of the primary coil springs 310. As such, there is a distance D2 between the upper ends 412 of the interstitial coil springs 410 and the upper ends 312 of the primary coil springs 310 which is the difference between the height, H3, of the primary coil springs 310, and the height, H4, of the interstitial coil springs 410.

[0059] When an exemplary spring core that includes the primary coil springs 310 and interstitial coil springs 410 shown in FIG. 2 is compressed up to the distance D2, only the interstitial coil springs 410 will compress the distance D2 until the compressed height of the interstitial coil springs 410 is the same as the uncompressed height, H3, of the primary coil springs 310. At that point, the upper ends 412 of the interstitial coil springs 410 are substantially planar with the upper ends 312 of the primary coil springs 310. During further compression of the spring core beyond the distance D2, both the primary coil springs 310 and interstitial coil springs 410 compress simultaneously. Once again though, it should be appreciated that the above description is simplified as the engagement and compression characteristics of the primary coil springs 310 and interstitial coil springs 410 will depend, in part, on how the primary coil springs 310 and interstitial coil springs 410 are connected, as discussed further below.

[0060] Referring now to FIG. 3, in another exemplary embodiment, a plurality of primary springs 510 are provided which are substantially the same as the primary coil springs 110 described above with respect to FIG. 1. A plurality of interstitial coil springs 610 are also provided which are similar to the interstitial coil springs 210 described above with respect to FIG. 1 including that the uncompressed height, He, of the interstitial coil springs 610 is less than the uncompressed height, Hs, of the primary coil springs 510. Unlike FIG. 1, however, in the exemplary embodiment shown in FIG. 3, the lower ends 614 of the interstitial coil springs 610 are not substantially planar with the lower ends 514 of the primary coil springs 510. Likewise, the upper ends 612 of the interstitial coil springs 610 are not substantially planar with the upper ends 512 of the primary coil springs 510. In other words, the lower ends 614 of the interstitial coil springs 610 define a plane that is not the same as a plane defined by the lower ends 514 of the primary coil springs 510 and the upper ends 612 of the interstitial coil springs 610 define a plane that is not the same as a plane defined by the upper ends 512 of the primary coil springs 510.

[0061] As such, there is a distance, Dau, between the upper ends 612 of the interstitial coil springs 610 and the upper ends 512 of the primary coil springs 510 and there is a distance, Dau between the lower ends 614 of the interstitial coil spring 610 and the lower ends 514 of the primary coil springs 510. Collectively, these two distances, Dau and Dau, equal the difference between the height, Hs, of the primary coil springs 510 and the height, He, of the interstitial coil springs 610. In some embodiments, the distance, Dau, between the upper ends 612 of the interstitial coil springs 610 and the upper ends 512 of the primary coil springs 510 is equal to the distance, D3L, between the lower ends 614 of the interstitial coil spring 610 and the lower ends 514 of the primary coil springs 510 such that interstitial coil springs 610 are positioned in themiddle of the primary coil springs 510. However, in other embodiments, D.ru and D3L may not be equal such that the interstitial coil springs 610 are closer to the upper end 512 or the lower end 514 of the primary coil springs 510. Furthermore, in some particular embodiments, the relative position of each interstitial coil springs relative to its neighboring primary coil springs can vary between interstitial coils.

[0062] When an exemplary spring core that includes the primary coil springs 510 and interstitial coil springs 610 shown in FIG. 3 is initially compressed, only the primary coil springs 510 will compress until the interstitial coil springs 410 are engaged. During further compression of the spring core, both the primary coil springs 510 and interstitial coil springs 610 compress simultaneously. Once again, it should be appreciated that the engagement and compression characteristics of the primary coil springs 510 and interstitial coil springs 610 will depend, in part, on how the primary coil springs 510 and interstitial coil springs 610 are connected, as discussed further below.

[0063] Referring now to FIG. 4, in another exemplary embodiment, a plurality of primary coil springs 710 are provided which are substantially the same as the primary coil springs 110 described above with respect to FIG. 1. A plurality of interstitial coil springs 810 are also provided which are similar to the interstitial coil springs 210 described above with respect to FIG. 1 except that in the embodiment shown in FIG. 4, the height, Hs, of the interstitial coil springs 810 is greater than the height, H7, of the primary coil springs 710. Also unlike FIG. 1, in the exemplary embodiment shown in FIG. 4, the lower ends 814 of the interstitial coil springs 810 are not substantially planar with the lower ends 714 of the primary coil springs 710. Likewise, the upper ends 812 of the interstitial coil springs 810 are not substantially planar with the upper ends 712 of the primary coil springs 710. As such, there is a distance, D4U, between theupper ends 812 of the interstitial coil springs 810 and the upper ends 712 of the primary coil springs 710 and there is a distance, D4L, between the lower ends 814 of the interstitial coil spring 810 and the lower ends 714 of the primary coil springs 710. Collectively, these two distances, D4U and D4L, equal the difference between the height, H7, of the primary coil springs 710 and the height, Hs, of the interstitial coil springs 810. In some embodiments, the distance, D4U, between the upper ends 812 of the interstitial coil springs 810 and the upper ends 712 of the primary coil springs 710 is equal to the distance, D4L, between the lower ends 814 of the interstitial coil springs 810 and the lower ends 714 of the primary coil springs 710 such that primary coil springs 710 are positioned in the middle of the interstitial coil springs 810. However, in other embodiments, D4U and D4L may not be equal such that the primary coil springs 710 are closer to the upper end 812 or the lower end 814 of the interstitial coil springs 810. Furthermore, in some particular embodiments, the relative position of each primary coil spring relative to its neighboring interstitial coil springs can vary between primary coil springs.

[0064] With further regard to the exemplary spring core that includes the primary coil springs 710 and interstitial coil springs 810 shown in FIG. 4, when that spring core is initially compressed, only the interstitial coil springs 810 will compress until the primary coil springs 710 are engaged. During further compression of the spring core, both the primary coil springs 710 and interstitial coil springs 810 compress simultaneously. Once again, however, it should be appreciated that the engagement and compression characteristics of the primary coil springs 710 and interstitial coil springs 810 will depend, in part, on how the primary coil springs 710 and interstitial coil springs 810 are connected, as discussed further below.

[0065] It should be understood that the spring core 100 shown in FIG. 5 can be formed with any of the exemplary configurations of primary coil springs 110, 310, 510, 710 and interstitialcoil springs 210, 410, 610, 810 described above with respect to FIGS. 1-4 as well as other variations described but not shown. For example, the interstitial springs can be bottom justified (FIGS. 1-2), center justified (FIGS. 3-4), or top justified (not shown) without departing from the spirit and scope of the present invention. Each of these configurations will yield an increase in firmness upon partial compression as discussed above. It is contemplated, however, that center justified coils will result in increased firmness soonest as compared to bottom justified or top justified which may be advantageous when a firmer feel is desired.[0066| As a further refinement of the present invention, however, and turning now to FIGS. 6-10, it is also contemplated that any of the above-described configurations of primary coil springs 110, 310, 510, 710 and interstitial coil springs 210, 410, 610, 810 as well as other variations described but not shown can be provided in a spring assembly that comprises a first support zone having a first compression characteristic and a second support zone having a second compression characteristic.

[0067] Referring now specifically to FIG. 6, in one embodiment of the present invention, an exemplary spring core 1000 is provided that comprises a first support zone including a plurality of primary coil springs arranged in a matrix and a plurality of interstitial coil springs positioned between adjacent primary coil springs, and a second support zone including a plurality of primary coil springs arranged in a matrix and a plurality of interstitial coil springs positioned between adjacent primary coil springs. In the embodiment shown in FIG. 6, the spring core 1000 can be characterized as including a head portion 1091, a foot portion 1093, and a middle portion 1092 positioned between the head portion 1091 and the foot portion 1093. The first support zone comprises the head portion 1091 and the foot portion 1093, and the second support zone comprises the middle portion 1092. More specifically, the head portion 1091 and the foot portion1093 (i.e., the first support zone) of the spring core 1000 comprise a plurality of primary coil springs 1012 and interstitial coil springs 1014 which collectively provide a first support characteristic and the middle portion 1092 (i.e., the second support zone) comprises a plurality of primary coil springs 1016 and interstitial coil springs 1018 which collectively provide a second support characteristic different than the first support characteristic. As one example, the plurality of primary coil springs 1012 and interstitial coil springs 1014 of the first support zone may be formed substantially similar to the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1, and the plurality of primary coil springs 1016 and interstitial coil springs 1018 of the second support zone may be formed substantially similar to the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2.

[0068] Referring now specifically to FIG. 7, in another exemplary spring core 2000 with a first support zone and a second support zone, the spring core 2000 can be characterized as including six alternating support areas or portions 2091-2096 having substantially similar sizes. The first support zone comprises the first portion 2091, the third portion 2093, and the fifth portion 2095, and the second support zone comprises the second portion 2092, the fourth portion 2094, and sixth portion 2096. More specifically, the first support zone of the spring core 2000 comprise a plurality of primary coil springs 2012 and interstitial coil springs 2014, which collectively provide a first support characteristic, and the second support zone of the spring core 2000 comprises a plurality of primary coil springs 2016 and interstitial coil springs 2018, which collectively provide a second support characteristic different than the first support characteristic. As one example, the plurality of primary coil springs 2012 and interstitial coil springs 2014 of the first support zone may be formed substantially similar to the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1, and the plurality of primary coil springs 2016 andinterstitial coil springs 2018 of the second support zone may be formed substantially similar to the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2.[0069J Referring now to FIG. 8, in another exemplary spring core 3000 with a first support zone and a second support zone, the spring core 3000 can be characterized as including five alternating support areas or portions 3091-3095 that have varying sizes. In FIG. 8 the first portion 3091, second portion 3092, and fourth portion 3094 are each substantially the same size, and the third portion 3093 and fifth portion 3095 are each substantially the same size and larger than the other zones. This is again merely illustrative though and should not be considered limiting. The first support zone comprises the first portion 3091, the third portion 3093, and the fifth portion 3095, and the second support zone comprises the second portion 3092 and the fourth portion 3094. More specifically, the first support zone of the spring core 3000 comprise a plurality of primary coil springs 3012 and interstitial coil springs 3014, which collectively provide a first support characteristic, and the second support zone of the spring core 3000 comprises a plurality of primary coil springs 3016 and interstitial coil springs 3018, which collectively provide a second support characteristic different than the first support characteristic. As one example, the plurality of primary coil springs 3012 and interstitial coil springs 3014 of the first support zone may be formed substantially similar to the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1, and the plurality of primary coil springs 3016 and interstitial coil springs 3018 of the second support zone may be formed substantially similar to the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2.

[0070] Referring now to FIG. 9, in another exemplary spring core 4000 with a first support zone and a second support zone, the spring core 4000 can be characterized as including a torso support portion 4091, a leg support portion 4092, and a peripheral portion 4093 positionedaround each of the torso support portion 4091 and leg support portion 4092. The first support zone comprises the torso support portion 4091 and leg support portion 4092, and the second support zone comprises the peripheral portion 4093. More specifically, the first support zone of the spring core 4000 comprise a plurality of primary coil springs 4012 and interstitial coil springs 4014, which collectively provide a first support characteristic, and the second support zone of the spring core 4000 comprises a plurality of primary coil springs 4016 and interstitial coil springs 4018, which collectively provide a second support characteristic different than the first support characteristic. As one example, the plurality of primary coil springs 4012 and interstitial coil springs 4014 of the first support zone may be formed substantially similar to the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1 and the plurality of primary coil springs 4016 and interstitial coil springs 4018 of the second support zone may be formed substantially similar to the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2.

[0071] Referring now specifically to FIG. 10, in another exemplary spring core 5000 with a first support zone and a second support zone, the spring core 5000 can be characterized as including a left side 5091 and a right side 5092. The first support zone comprises the left side 5091 and the second support zone comprises the right side 5092. More specifically, the first support zone of the spring core 5000 comprises a plurality of primary coil springs 5012 and interstitial coil springs 5014, which collectively provide a first support characteristic, and the second support zone of the spring core 5000 comprises a plurality of primary coil springs 5016 and interstitial coil springs 5018, which collectively provide a second support characteristic different than the first support characteristic. As one example, the plurality of primary coil springs 5012 and interstitial coil springs 5014 of the first support zone may be formedsubstantially similar to the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1, and the plurality of primary coil springs 5016 and interstitial coil springs 5018 of the second support zone may be formed substantially similar to the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2.

[0072] Turning now to FIGS. 11 A-l IF, in additional exemplary spring cores, the interstitial springs included in the spring cores can be further arranged to provide improved edge support (e.g., a firmer edge upon compression). For instance, in one embodiment and with reference to FIG. 11 A, a spring core 6000a is provided having rows 6091, 6092, 6093, 6094 of primary coil springs 6012 with interstitial coils springs 6014 arranged along the outermost longitudinal edge of the outer rows 6091, 6094 of coil springs. Similarly, in another embodiment and as shown in FIG. 1 IB, a spring core 6000b is provided in which the interstitial coil springs 6014 are positioned between the outer two rows 6091, 6092 of primary coil springs 6012 on one side of the spring core 6000b and between the outer two rows 6093, 6094 of primary coil springs 6012 on the other side of the spring core 6000b. In a further embodiment and as shown in FIG. 11C, a spring core 6000c is provided having rows 6091, 6092, 6093, 6094 of primary coil springs 6012 and in which the interstitial coil springs 6014 are positioned both along the outermost edge of the outer rows 6091, 6094 of coils springs as well as between the outer two rows 6091, 6092 of primary coil springs 6012 on one side of the spring core 6000c and between the outer two rows 6093, 6094 of primary coil springs 6012 on the other side of the spring core 6000c.|0073] FIGS. 1 ID-1 IF show additional springs cores 6000d-6000f in which edge support is provided by the arrangement of interstitial coil springs. In FIG. 1 ID, a spring core 6000d is provided in which the spring core 6000d includes rows 6091, 6092, 6093, 6094 of primary coil springs 6012 with interstitial coil springs 6014 arranged around the entire perimeter of the springcore 6000d to provide improved edge support. In FIG. 1 IE, a spring core 6000e is provided in which, similar to the spring core 6000b shown in FIG. 1 IB, the interstitial coil springs 6014 are positioned between the two rows 6091, 6092 of primary coil springs 6012 on one side of the spring core 6000b and between the two rows 6093, 6094 of primary coil springs 6012 on the other side of the spring core 6000b, but are then also positioned between primary coil springs 6012 between the inner rows 6092, 6093 at both ends of the inner rows 6092, 6093. FIG. 1 IF then shows a combination of the arrangements shown in FIGS. 1 ID-1 IE. In FIG. 1 IF, a spring core 6000f is provided having interstitial coil springs 6014 arranged around the entire perimeter of the spring core 6000f as well as interstitial coil springs 6014 positioned between the two rows 6091, 6092 of primary coil springs 6012 on one side of the spring core 6000f, between the two rows 6093, 6094 of primary coil springs 6012 on the other side of the spring core 6000f, and between the inner rows 6092, 6093 of primary coils springs 6012 at the ends of each of the inner rows 6092, 6093.

[0074] As a further refinement, and referring now to FIGS. 12A-12C, in other exemplary spring cores 7000a-7000c, interstitial springs 7014 are arranged in relation to primary coil springs 7012 such that the spring cores 7000a-7000c are configured to provide additional structural support and a reduction in motion transfer across the spring cores 7000a-7000c. In one embodiment, for example and as shown in FIG. 12A, a spring core 7000a is provided that includes rows 7091, 7092, 7093, 7094 of primary coil springs 7012 with interstitial springs 7014 positioned between the centermost rows 7092, 7093 to provide a centermost portion of the spring core 7000a with support characteristics different than those of the two opposing side rows 7091, 7092 of the spring core 7000a and to thereby reduce motion transfer across the spring core 7000a. With reference to FIG. 12B, improvements in length stability, particularly for shippingpurposes, can also be provided by providing a spring core 7000b having rows 7091, 7092, 7093, 7094 of primary coil springs 7012 with interstitial coil springs 7014 positioned between each of the primary coil springs 7012 in the spring core 7000b. In some embodiments, and referring now to FIG. 12C, further reductions in side-to-side motion transfer are provided by providing a spring core 7000c that includes a plurality of rows 7091, 7092, 7093, 7094, 7095 of primary coil springs 7012 with two rows of interstitial coil springs 7014 extending longitudinally along the centermost portion of the spring core 7000c, instead of just the single row of interstitial coil springs 7014 shown in FIG. 12A.

[0075] Referring now to FIGS. 13-16, it is contemplated that a number of other unique zoning options can also be provided through arranging the interstitial and primary coil springs in the spring cores of the present invention. As one embodiment of such a zoning option, and with reference to FIG. 13, a spring core 8000 comprised of a plurality of primary coil springs 8012 is provided with interstitial coil springs 8014 positioned in only a center portion of the spring core 8000. In this regard, the spring core 8000 is thus effectively divided into an upper support zone 8091, a central support zone 8092, and a lower support zone 8093 where the support characteristics of the upper support zone 8091 and lower support zone 8093 are different than the support characteristics of the central support zone 8092 including the interstitial springs 8014.

[0076] Referring now to FIG. 14, FIG. 14 provides another zoning arrangement similar to that shown in FIG. 13, but provides five support zones rather than three support zones. In particular, FIG. 14 shows a spring core 8100 comprising a plurality of primary coil springs 8112 that includes a single row of interstitial coil springs 8114 positioned in a lower portion of the spring core 8100, two rows of interstitial coil springs 8114 positioned in a center portion of the spring core 8100, and a single row of interstitial coil springs 8114 positioned in an upper portionof the spring core 8100. By positioning the interstitial coil springs 8114 in such a manner, the spring core 8100 is then effectively divided into five support zone 8191, 8192, 8193, 8194, 8195 with the interstitial coil springs 8114 in the upper and lower portions of the spring core 8100 forming an upper support zone 8191 and lower support zone 8195 having the same support characteristics, and with the two rows of interstitial coil springs 8114 in the center portion of the spring core 8100 forming a central support zone 8193 having support characteristics different than the support characteristics of the upper support zone 8191 and lower support zone 8195. Two intermediate support zones 8192, 8194 are then positioned between the upper support zone 8191 and central support zone 8193 and between the lower support zone 8195 and the central support zone 8193, respectively, with the two intermediate support zones 8192, 8194 having the same support characteristics as one another but different than the support characteristics of the upper support zone 8191, the central support zone 8193, and the lower support zone 8195.

[0077] As additional support zoning options, in one embodiment and with reference to FIG. 15, a spring core 8200 is provided having an alternating arrangement of firmer and softer zones by positioning interstitial coil springs 8214 between every other lateral row of primary coil springs 8212. Such an alternating arrangement of interstitial coil springs 8214 thus provides a plurality of firmer zones 8291 characterized by the presence of interstitial coil springs 8214, and a plurality of softer zones 8292 characterized by the presence of only the primary coil springs 8212. Such a concept of firmer and softer areas on a spring core can also be provided by positioning of interstitial coils spring in various other arrangements in a spring core, such as in the spring core 8300 shown in FIG. 16 where the interstitial coil springs 8314 are arranged in a checkerboard-type arrangement among the primary coil springs 8312.

[0078] In addition to the unique zoning options show in FIGS. 13-16, unique zoning options can also be provided in accordance with the present invention by arranging interstitial coil springs having various heights in different positions on an exemplary spring core. For instance, with reference to FIG. 17, a spring core 9000 is provided having an upper zone 9091 including primary coil springs 9012 and interstitial springs 9018 having a height less than the primary coil springs 9012, a central support zone 9092 including primary coil springs 9012 and interstitial springs 9014 with a height greater than the primary coil springs 9012, and a lower support zone 9093 having primary coil springs 9012 and interstitial coil springs 9018 having a height less than the primary coil springs 9012. In this way, the upper support zone 9091 and lower support zone 9093 are made to have the same or similar support characteristics while the central support zone 9092 has support characteristics different then the upper support zone 9091 and lower support zone 9093.

[0079] As another example, to provide support zones with different support characteristics and referring to FIG. 18, a spring core 9100 is provided having an upper support zone 9191 including primary spring coils 9112 and interstitial coils 9118 having a height less than the primary spring coils 9112, a first intermediate support zone 9192 positioned adjacent to and below the upper support zone 9191 and including only primary spring coils 9112, a central support zone 9193 positioned below and adjacent to the first intermediate support zone 9192 and including primary spring coils 9112 and interstitial coils 9114 having a height greater the primary spring coils 9012, a second intermediate support zone 9194 positioned below and adjacent to the central support zone 9193 and including only primary spring coils 9112, and a lower support zone 9195 including primary spring coils 9112 and interstitial coils 9118 having a height less the primary spring coils 9112.

[0080] As yet another example of spring cores making use of interstitial coils having various heights to provide different support zones, and referring now to FIG. 19, a spring core 9200 is provided having primary coil springs 9212 and an alternating arrangement of rows of interstitial coil springs 9214 having a height greater than the primary coil springs 9212 and rows of interstitial coil springs 9218 having a height less than the primary coil springs 9212 to thereby provide an alternating soft and firm arrangement. Similarly, in anther embodiment and with reference to FIG. 20, a spring core 9300 is provided including primary coil springs 9312 where interstitial coil springs 9314 having a height greater than the primary coil springs 9312 and interstitial coil springs 9318 having a height less than the primary coils springs 9212 are arranged in a checkerboard-type arrangement among the primary coil springs 9312 to thereby provide softer and firmer areas across the spring core 9300.|0081] With further respect to the arrangements of coil springs shown in FIGS. 6-20, it is of course appreciated that the patterns shown in FIGS. 6-20 are not limiting in any way and a spring core of the present invention can have any number of different patterns including any number of different zones across the spring core without departing from the spirit and scope of the present invention. Similarly, although the plurality of primary coil springs 110 and interstitial coil springs 210 of FIG. 1 and the plurality of primary coil springs 310 and interstitial coil springs 410 of FIG. 2 were used as an example for certain of FIGS. 6-20, spring cores made in accordance with the present invention may use any combination of the above-described configurations shown in FIGS. 1-4. Of course, it is further contemplated that while the schematic drawings of the exemplary spring cores shown in FIGS. 6-20 are depicted as having a defined number of rows of primary coil springs for purposes of illustration, the interstitial springs and various patterns described herein can be incorporated into and utilized with anynumber of rows of primary coil springs without departing from the spirit and scope of the subject matter described herein. Likewise, each spring core may have more than two different forms of primary coil springs and / or interstitial coil springs without departing from the spirit and scope of the present invention.[0082| Moreover, in FIGS. 6-10, the boundaries between different zones are illustrated as extending through the middle of certain coil springs. This is of course merely for ease of illustration and a person of ordinary skill would readily understand that the boundary or transition between the different zones can be accomplished in a variety of ways so as to provide an intended response characteristic of the spring core. For example, and as shown in certain of the embodiments depicted in FIGS. 6-20, coils along the boundary or in other parts of the spring cores may alternate in which zone they belong or the coils along the boundary or in other parts of the spring cores may be configured to transition between the two zones.

[0083] Furthermore, in some embodiments, rather than having zones that include one single configuration of primary coil springs and interstitial coil springs, a spring core (or one or more zones within the spring core) made in accordance with the present invention may have a gradual transition across one dimension (e.g., the length or width) or two dimensions (e.g., both length and width). The transition may extend across any number of primary coil springs and / or interstitial coil springs. In one particular embodiment of the present invention, a spring core is provided with a gradient of support across the spring core. For example, and with reference to FIG. 21, the support may initially increase from a head portion (leftmost in the graph in FIG. 21) to a torso portion (middle of the graph in FIG. 21) before decreasing at a foot portion (rightmost in the graph in FIG. 21). Of course, this is also merely exemplary and the support characteristics may vary according to any number shapes. The means of varying support between coil springs isalso non-limiting and any combination of primary coil springs and interstitial coil springs discussed above may be chosen for each location in the spring core to achieve the desired support characteristics. However, it is contemplated that one particular means is to vary the location of the upper end of the interstitial coil springs relative to the upper end of the primary coil springs in a manner corresponding to the desired support. That is to say with reference to the graph of FIG. 21, the location of the upper end of the interstitial springs along the location corresponds to the support, i.e., initially increasing from a head portion (leftmost in the graph in FIG. 21) to a torso portion (middle of the graph in FIG. 21) before decreasing at a foot portion (rightmost in the graph in FIG. 21). In one particular embodiment, the upper end of the interstitial springs may change in height between about 5 mm to about 20 mm over one or more rows. Of course, the particular height changes (both incremental and total) as well as the distance over which the changes occur are not limited and will depend on the particular intended support characteristic.

[0084] As previously mentioned, the exemplary primary coil springs 110, 310, 510, 710 and exemplary interstitial coil springs 210, 410, 610, 810 include a flexible enclosure, or pocket, encasing the helical wire. As such, in some embodiments, adjacent coils are interconnected via the flexible enclosures to form strands. In some embodiments, strands of entirely interstitial coil springs are placed between two strands of primary coil springs to form the spring cores described above. In other embodiments, a strand may include alternating primary coil springs and interstitial coil springs and two of these strands can be placed adjacent to each other to form the spring cores described above. In embodiments with alternating coils, the different relative positions of the primary coil springs and interstitial coil springs shown, for example, in FIGS. 1- 4 can be controlled by varying the location of a seam along the bottom and / or top of the strand.Once again, these seams by be formed by ultrasonic weld, thermal weld, stitching, metal staples, or other suitable methods. Other methods of manufacturing the spring cores are also contemplated including unpocketed coil springs interconnected by wires or other means known in the art.[0085| In any event, and as mentioned above, the engagement of and compression characteristics of the primary coil springs and interstitial coil springs will depend, in part, on how the coil is connected within a strand and / or to adjacent strands. According to some exemplary implementations in which the coil springs are connected with one or more glue lines, it is contemplated that the number and placement of the glue lines will have various effects on the performance of the spring core. For example, glue lines placed close to the top and / or bottom of the interstitial springs is contemplated to provide increased firmness and help minimize noise caused by coil-to-coil contact. Conversely, glue lines placed closer to the middle of the interstitial springs is contemplated to provide a softer feel but may increase the risk of noise.

[0086] Although the exemplary spring cores shown in FIGS. 5-20 have the plurality of primary coil springs arranged in a square or rectangular grid (i.e., along columns and rows), it is further contemplated that other arrangements are possible without departing from the spirit and scope of the present invention. For example, the primary coil springs may be arranged in rows, or strings, with adjacent strings positioned such that there is an offset between primary coil springs in adjacent springs. The resulting spaces between the plurality of coil springs would thereby change requiring adjustments to the size, spacing, and / or placement of the respective interstitial coil springs.

[0087] Furthermore, while the exemplary spring cores shown in FIGS. 5-20 include interstitial coil springs filling each possible space between adjacent primary coil springs, in someembodiments, in addition to varying the relative height of coil springs used to provide the zoned support discussed above and as shown in FIGS. 11 A-20, one or more of the spaces between primary coil springs may not be filled by an interstitial coil spring to also affect the support characteristics in that area.

[0088] Lastly, while the exemplary spring cores may be described herein with reference to a mattress, it is appreciated that the exemplary spring cores disclosed herein are not necessarily limited to use in a mattress, but, rather, may be incorporated into a variety of support cushion that support various portions of a user’s body without departing from the spirit and the scope of the present invention. In this regard, the term “support cushion” as used herein may include, for non-limiting example, various types of supports including bedding and / or cushions for chairs and furniture, pillows, padding for medical devices and equipment (e.g., wheelchair seat pads, wheelchair padding, medical pads, hospital gurney pads, operating table pads, positioning pads), padding for furniture (e.g., upholstery padding, furniture cushions, furniture pads), padding for athletic equipment and devices (e.g., athletic cushions, sports and athletic padding, gymnastic mats), padding for recreational equipment and devices (e.g., camping and sleeping mats), padding for apparel (e.g., bra straps, shoulder pads, shoe linings, boot linings), padding for household goods (e.g., anti-fatigue mats, mattress pads, mattress covers, mattress “toppers,” the pillow-top portion of pillow-top mattresses, pillows, and the like); padding accessories (e.g., briefcase shoulder straps, computer carrying cases, purses, gloves, and the like), pet beds, and the like. Thus any of these types of structures, and others, may fall within the scope of the term “support cushion” as used herein and can be utilized with an exemplary spring core of the present invention.

[0089] One of ordinary skill in the art will recognize that additional embodiments are also possible without departing from the teachings of the present invention or the scope of the claims which follow. This detailed description, and particularly the specific details of the exemplary embodiments disclosed herein, is given primarily for clarity of understanding, and no unnecessary limitations are to be understood therefrom, for modifications will become apparent to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the claimed invention.

Claims

CLAIMSWhat is claimed is:

1. A spring core of a mattress comprising: a first support zone including a plurality of primary coil springs arranged in a matrix, each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end, and a plurality of interstitial coil springs positioned between adjacent primary coil springs, each of the interstitial coil springs having an upper end and a lower end with an uncompressed height of the interstitial coil defined between the upper end and the lower end; and a second support zone including a plurality of primary coil springs arranged in a matrix, each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end, and a plurality of interstitial coil springs positioned between adjacent primary coil springs, each of the interstitial coil springs having an upper end and a lower end with an uncompressed height of the interstitial coil defined between the upper end and the lower end; wherein the height of the plurality of interstitial coil springs of the first support zone differs from the height of the plurality of primary coil springs of the first support zone by a first distance such that the first support zone has a first support characteristic; and wherein the height of the plurality of interstitial coil springs of the second support zonediffers from the height of the plurality of primary coil springs of the second support zone by a second distance different than the first distance such that the second support zone has a second support characteristic different than the first support characteristic.

2. The spring core of claim 1, wherein the first distance is zero such that the height of the plurality of interstitial coil springs of the first support zone is the same as the height of the plurality of primary coil springs of the first support zone.

3. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs.

4. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, the plurality of primary coil springs are arranged in a square grid and each of the plurality of interstitial coil springs is positioned between four adjacent primary coil springs.

5. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, the height of the plurality of interstitial coil springs is less than the height of the plurality of primary coil springs.

6. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, the height of the plurality of interstitial coilsprings is greater than the height of the plurality of primary coil springs.

7. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, the lower end of each of the plurality of interstitial coil springs is substantially planar with the lower end of each of the plurality of primary coil springs.

8. The spring core of claim 1, wherein for either the first support zone, the second support zone, or both the first and second support zones, the lower end of each of the plurality of interstitial coil springs defines a plane that is not the same as a plane defined by the lower end of each of the plurality of primary coil springs.

9. The spring core of claim 1, wherein the spring core can be characterized as including a foot portion, a head portion, and a middle portion positioned between the foot portion and the head portion, wherein the first support zone comprises the foot portion, the head portion, or both the foot portion and the head portion, and wherein the second support zone comprises the middle portion.

10. The spring core of claim 1, wherein the first support zone and the second support zone comprise multiple alternating zones.

11. The spring core of claim 1, wherein the spring core can be characterized as including a central portion and a peripheral portion extending around the central portion, wherein the first support zone comprises the central portion, and wherein the second support zone comprises the peripheral portion.

12. The spring core of claim 1, wherein the spring core can be characterized as including a torso support portion and a leg support portion, and wherein the second support zone comprises the torso support portion and the leg support portion.

13. The spring core of claim 1, wherein the spring core can be characterized as including a left side portion and a right side portion, and wherein the first support zone comprises the left side portion, and wherein the second support zone comprises the right side portion.

14. A spring core of a mattress comprising: a first support zone including a plurality of primary coil springs arranged in a matrix, each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end, and a second support zone including a plurality of primary coil springs arranged in a matrix, each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end, anda plurality of interstitial coil springs positioned between adjacent primary coil springs, each of the interstitial coil springs having an upper end and a lower end with an uncompressed height of the interstitial coil defined between the upper end and the lower end; wherein the height of the plurality of interstitial coil springs of the second support zone differs from the height of the plurality of primary coil springs of the second support zone by a first distance; and wherein the first support zone has a support characteristic different from the second support zone.

15. The spring core of claim 14, wherein a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs of the second support zone.

16. The spring core of claim 14, wherein the height of the plurality of interstitial coil springs is less than the height of the plurality of primary coil springs of the second support zone.

17. The spring core of claim 14, wherein the height of the plurality of interstitial coil springs is greater than the height of the plurality of primary coil springs of the second support zone.

18. The spring core of claim 14, wherein the second support zone extends along a longitudinal edge of the spring core.

19. A spring core for a support cushion comprising:a plurality of primary coil springs arranged in a matrix, each of the primary coil springs having an upper end and a lower end with an uncompressed height of the primary coil defined between the upper end and the lower end, and a plurality of interstitial coil springs positioned between adj cent primary coil springs, each of the interstitial coil springs having an upper end and a lower end with an uncompressed height of the interstitial coil defined between the upper end and the lower end, and each of the interstitial coil springs having a height greater than or less than the height of the plurality of primary coil springs of the second support zone.

20. The spring core of claim 19, wherein a diameter of the plurality of interstitial coil springs is less than a diameter of the plurality of primary coil springs.

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