INNERSPRING CONSTRUCTION WITH SPRINGS HAVING FREE TERMINAL CONVOLUTIONS

Abstract: An innerspring assembly (10), such as for use in a mattress, comprises a plurality of coil springs (12) defining upper (22) and lower (24) terminal convolutions and body portions therebetween. Adjacent coil springs (12) are attached together at the body portions thereof with the terminal convolutions (22, 24) being unattached to one another, so that the terminal convolutions (22, 24) can move independently of one another.

Description: INNERSPRING CONSTRUCTION WITH SPRINGS HAVING FREE TERMINAL CONVOLUTIONS FIELD OF THE INVENTION The present invention relates to a novel innerspπng assembly, and particularly, one adapted for use as a mattress BACKGROUND OF THE INVENTION Innerspπng assemblies are conventionally made from arrays of vertically-oπented coil springs (i e , the longitudinal axes of the typical helical spπngs are perpendicular to the innerspπng support surface) The spπngs are arranged m a generally side-by-side arrangement, usually in parallel columns and parallel rows, to form a support surface To secure tne individual spnng coils together and thereby form a unitary innerspπng assembly, some foπn of attachment means is normally employed such as clips, cross-helical spπngs and the like Usually adjacent spπngs are attached together at their terminal convolutions, 1 e , the metal tuπi at the very top and bottom of the spπngs See, for example, Bell U S 2,611 ,910, and particularly Flesher et al U S 4,726,572 Another design for uniting coil spring-; in an mnerspring assembly employs pocketed coil springs, l e , individual coil spnngs which are each encased in a "cell" made from fabnc or other flexible material To form an integral mnerspring assembly for these pocketed coil spπngs, the individual flexible covers of the pocketed coil spπngs are attached to one another by sewing, stπngs, hot melt adhesives or other means The spnngs themselves are, however, typically not interconnected except through this joining of their pockets Each of these designs has its own advantages For example, the pocketed coil design offers a degree of mobility between individual spπngs, in particular because the terminal convolutions of adjacent coils are not directly secured together A certain amount of "float" between spπngs is therefore available Conventional designs using clipped or otherwise wire-joined spnng ends tend to offer supeπor longevity and ease of manufacture, in part because the use of fabπcs is eliminated A pπncipal objective of the present invention is to provide a novel innerspπng assembly design, particularly for use m an innerspπng mattress, which provides a conventional joining of adjacent spnngs through the use of cross-helical connections, for example, but which also successfully incorporates a degree of freedom or mobility for the spπngs to achieve a spnng "float" or flexibility to the spnng ends S UMMARY OF THE I NVENTION This and other ob j ectives are accomplished by the present invention which compnses in one of its broadest expressions j oining adjacent spnngs at a turn other than the terminal convolution For example, ad j acent coil springs are j oined at the first or second tuπi inboard (l e , along the spnng axis) from the terminal convolution This leaves one or two turns outboard of the point of joining which are unattached as between other spπngs This free end constniction thus has the ability to readily move in response to a load, particularly advantageous if the load is off-axis (such as a load with a lateral component relative to the support surface) A "free-floating' support surface is therefore available through this inventive innerspπng assembly, vet the springs themselves can be j oined together m a very stable array using conventional manufactuπng techniques (e g , cross- helical connections) Thus, in accordance with the present invention, a helical spring for use in an innerεpring assembly made from a plurality of springs has a compressible body portion comprised of a plurality of coil turns, a terminal convolution at each end of the body portion, and al least one offset segment formed on a coil turn of the body portion. As a practical matter, coil turns on each end of the body portion would have such offset segments, since helical springs are generally manufactured with axial symmetry. The coil tum(s) of the body portion having the offset segments are spaced from a respective terminal convolution, such as being on the next turn inboard from the terminal convolution, the second tuπi inboard, etc. The offset segment(s) are adapted for engagement with means for interconnecting a plurality of these springs together in the innerspring assembly. Such an interconnection would be by clips or cross-helical springs, for example. By so connecting the springs at points inboard from the terminal convolution, the latter and any intermediate turns remain free of the interconnecting means when the springs are in the innerspring assembly. This yields a free end for the spring, which provides the noted "float" to the spring end, and flexibility to the support surface that the spring ends define for the innerspring. Depending on where the engagement is made along the body portions of adjacent springs in the innerspring, the "float" or flexibility can be thereby adjusted. In an embodiment of the invention, the innerspring is an array of helical coil springs arranged in orthogonal rows and columns. Each of the individual coil springs have a terminal convolution at each end thereof and a body portion made up of a number of turns therebetween. Capitalizing on a spring conεtniction similar to that disclosed in the aforementioned U.S. 4,726,572, which employs laterally offset portions on the spring which are overlapped and then laced together using a small diameter cross-helical spring, the aforementioned offset portions are formed on a turn spaced inboard from the terminal convolutions of springs in the inventive assembly. Accordingly, rather than attaching adjacent coil springs to one another at their terminal convolutions as accomplished in the prior art, the springs of the inventive innerspring are attached to each other at these offset portions at a point spaced axially inboard from the end of the spring. The manufacturing techniques for applying the cross-helicals for joining the springs remains virtually unchanged. The terminal convolutions of adjacent springs are not attached to one another, leaving one or more tuπis thereby free to act independently of one another in response to an applied load. As a result, the upper surface of the innerspring assembly is far more flexible and responsive to contour differences (i.e., a body lying thereon) than conventional pocketless designs in which the upper terminal convolutions are attached to one another, where the displacement of one spring in turn fairly immediately involves displacement of adjacent springs to which its terminal convolution is joined. The overall result achieved by the inventive free-end innerspring can be an improvement in comfort with all the advantages of "hard-wired" spring designs. The foregoing features and advantages of the present invention will be further understood upon consideration of the following detailed description of certain embodiments of the present invention with reference to the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic pictorial view of an innerspring assembly made in accordance with the present invention; FIG. 2 is a plan view of a section of an innerspring assembly such as shown in FIG. 1 illus¬ trating the attachment of a number of spring coils located in the interior of the inventive innerspring assembly; FIG. 3 is an elevational view taken along line 3-3 of FIG. 2; FIG. 4 is another elevational view taken along line 4-4 of FIG. 3 showing two adjacent springs joined together; FIG. 5 is a view similar to FIG. 2 illustrating specific features of one set of overlapped offset portions of the attachment convolutions in accordance with a preferred embodiment of the invention; and FIG. 6 is a view similar to FIG. 2 illustrating another embodiment of the invention in which coil springs are arranged in mirror-image relation and secured together along transverse directions. DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS As shown in FIG. 1 , an inventive innerspring assembly, generally indicated at 10, comprises a plurality of coil springs 12 (also referred to as "spring coils" or simply "springs") arranged side-by-side in rows 14 and columns 16 to thereby form an innerspring assembly generally rectangular in shape. The foregoing would represent a typical mattress innerspring, for example. While the embodiments discussed hereafter will generally relate to such a mattress innerspring, it will nonetheless be understood that the invention has application in other environments and other innerspring assemblies, such as furniture cushions and the like. Also, the reference to "rows" and "columns" herein is not meant to be limiting, since the terms could be used interchangeably depending on the point of reference taken. To hold the springs 12 in place and make an integral assembly, cross-helical springs 20 and helical border wire springs 18 are coiled around convolutions of the individual spring coils, as described more particularly below. The cross-helical and helical attachments remain conventional, however, which is an advantage of the present invention. As illustrated in FIGS . 3 and 4, for example, each coil spring 12 is composed of a single, continuous piece of wire stock which is generally helical in configuration and includes an upper terminal convolution or portion 22, a lower terminal convolution or portion 24, and a body portion made up of a number of tuπis of the wire stock. With particular reference to Figs. 2 and 4, an attachment convolution 28, 30 for attaching adjacent coils to one another is formed on one of the turns of body portion inboard of a respective terminal convolution 22, 24. The springs 12 are arranged so that portions of the attachment convolutions 28 of adjacent coils overlap one another; it is these overlapping segments which are secured together by means of the cross-helical springs 20. In the embodiments shown, upper terminal portion 22 is composed of a convolution of the helical coil which is substantially in the same plane AA. Likewise, the lower terminal portion or convolution 24 has the same shape as the other end of the spring 12, and is similarly disposed in plane BB. When organized into a support surface, these terminal convolutions 22, 24 will occupy a common respective plane AA, BB. Upper attachment convolutions 28 and lower attachment convolutions 30 are provided for allowing attachment of adjacent coils to one another These attachment convolutions are also relatively flattened so that a ma j or portion of the tuπi is in a respective common plane CC in the case of upper attachment convolution 28 and plane DD in the case of lower attachment convolution 30 Preferably, upper attachment convolutions 28 and lower attachment convolutions 30 have essentially the same shape as the terminal coils descπbed in commonly-assigned patent U S 4,726,572, the disclosure of which is incorporated herein by reference In essence, the terminal convolution descnbed in that patent is moved inboard to a body tuπi of the inventive spnng herein As illustrated m FIGS 2 and 6, these attachment convolutions are somewhat rectangular m shape, with first offset portions 32, second offset portions 34 and third offset portions 36 which are spaced radially (laterally) outwardly from the spnng coil axis and from a cyhndπcal shape generally defined by the circular coils of the body portion The third offset portions of the spnngs, or at least those of the spnngs located on the peπphery of the array, each have a stepped segment compnsing a substantially straight major part 38 extending generally perpendicular to the first and second offset portions, and short parts 40 extending from the ends of the straight part to the remaining portions 42 of the third offset portions 36 Attachment convolutions of this structure are advantageously employed, for example, m secuπng the coils located on the peπphery of the array to a border wire to prevent rotation of the third offset portion relative to the border wire, as descnbed in the above noted U S 4,726,572 Adjacent spnng coils, as illustrated in FIG 2 through 4, are attached to one another by means of cross-helical spπngs 20 used to join the overlapped attachment convolution portions together While overlapped segments are preferred, obviously spacing the attachment segments 32, 34 of adjacent spnngs closely together and joining them with the cross-helical spnngs 20 would also work, but is considered less desirable Since the terminal convolution tuπi outboard of the attachment is left free, when an external pressure or force is applied thereto, these free ends can readily move off-axis of their respective spnng (l e , shift sideways) and independently of any other spnng As a result, the inventive mnerspnng assembly is more flexible in use, since action on one spnng terminal convolution is not necessaπly directly translated to an adjacent spnng It is considered that the surface of an innerspnng having such "free" spnng ends will adjust itself much more readily to diverse contours applied to the surface of the innerspnng The overall result can be greater comfort to the user Moreover, since encasement fabncs are not involved as in pocketed spnngs, the mattress is considered to be more stable, long term, and is easier to manufacture than mattresses employing a pocketed spnng design, since conventional manufacturing techniques using clips and cross-helicals are employed In accordance with still another feature of the invention, the flexibility of an innerspnng assembly embodying the present invention — in other words the degree to which the upper portions or convolutions 22 of ad j acent spnngs are free to move independently of one another -- can be adjusted by varying the relative distance between planes AA and CC, between planes CC and DD, and between planes DD and BB, either individually or in combination Thus, for example, increasing the distance between planes AA and CC is considered to result in more flexibility of upper convolutions 22 relative to one another Adjustment of the distances between the different planes, and locating the interconnection planes with one, two or even more turns outboard from the same, yields a spring assembly which can be made having a desired degree of flexibility from a broad range of possible choices. The innerspring assembly of the present invention can be used to make innerspring mattresses of any type. Aβ well appreciated in the art, innerspring mattresses are typically made by covering at least the upper surface of the innerspring, defined by the upper terminal convolutions or portions of the coils, with insulators, flexible padding made from a flexible fabric or foam, ticking and the like. In the embodiment depicted in FIG. 6, springs in the interior of the array are provided with attachment convolutions having the generally rectangular shape illustrated in U.S. 4,726,572. This shape with the third offset allows adjacent interior coils to he secured together in pairs by helical springs in a transverse direction (i.e., in the direction of columns 16 of FIG. 1 ) in addition to longitudinally in the direction of rows 14. This can be done as shown in FIG. 6 by arranging adjacent springs in a row 14 in pairs, with the coils in each pair in mirror-image relation with one another so that the third offset portions 36 of the attachment convolutions of each spring pair overlap one another. Accordingly, while some embodiments of the present invention have been illustrated above, it should be appreciated that many modifications can be made without departing from the spirit and scope of the invention. For example, although the above illustrates cross-helical springs being used for attaching adjacent coils together, any attachment means can be used. For example, clips aβ illustrated in the above noted Bell patent can be employed. Also, the terminal portions 22 and 24 of the springs need not be helical or circular in configuration, but can be any configuration which will form a suitable support surface. Furthermore, the individual springs 12 can be made from multiple pieces rather than a single, continuous piece of wire as shown in the illustrated embodiments. Also, the attachment convolutions can have any shape, and in fact need not be convolutions at all, it being sufficient that the body portion of the springs define a stmcture allowing adjacent springs to be attached to one another at their body portions with the terminal portions being free to move with respect to one another. Finally, it is also within the scope of the invention that some terminal portions of springs in the innerspring could be loosely interconnected one to another, as by various engagements of the same to an insulator applied over the innerspring surface. Such an engagement would not defeat the free movement of the remainder of the terminal portions with respect to one another. So long as the majority of the terminal portions of the springs are free to move independently of one another in the axial direction, i.e., in the direction of the respective axes of the spring helixes, the advantages of the invention should be realized. All such modifications are intended to be included within the scope of the present invention.

Claims: WE CLAIM 1 A spnng for use m an innerspnng assembly made from a plurality of said spnngs, said spnng having a compressible body portion, a terminal convolution at the end of said body portion, and a segment located on said body portion and spaced from said terminal convolution which segment is adapted for engagement with means for interconnecting a plurality of said spπngs in the innerspnng assembly, such that said terminal convolution remains free of said interconnecting means when said spnng is in the innerspπng assembly 2 A helical spnng for use in an innerspnng assembly made from a plurality of said spπngs, said spnng having a compressible body portion compnsed of a plurality of coil tuπis, a terminal convolution at each end of said body portion, and at least one offset segment formed on a coil tun. of said body portion, said coil tuπi of said body portion having said offset segment being spaced from a respective one of said terminal convolutions, said offset segment being adapted for engagement with means for interconnecting a plurality of said spπngs in the innerspnng assembly, such that said respective one terminal convolution remains free of said interconnecting means when said spnng is in the innerspπng assembly 3 The spnng of claim 2 wherein at least one offset segment is formed on a coil turn of said body portion at each end of said spnng and spaced from a respective terminal convolution 4 The spnng of claim 3 wherein two offset segments are formed on opposite sides of a coil turn of said body portion at each end of said spnng and spaced from a respective terminal convolution, said offset segments having straight portions which are generally tangential to and laterally outboard from a cylmdncal shape generally defined by the tuπis of said body portion, said offset segments being located in substantially the same plane which is perpendicular to a longitudinal axis defined by said cylmdncal shape 5 The spnng of claim 4 wherein each said coil tuπi having said offset segments formed thereon is the first turn inboard from a respective terminal convolution 6 The innerspnng of claim 5 wherein each said coil tuπi having said offset segments formed thereon is the second turn inboard from a respective terminal convolution, said terminal convolution and a first turn inboard from said terminal convolution thereby being free of said interconnecting means 7 An innerspnng compπsing a plurality of spπngs organized into an array and defining a support surface to said innerspnng, means for interconnecting said spnngs into said array, each said spnng having a compressible body portion, a terminal convolution at the end of said body portion, and a segment located on said body portion and spaced from said terminal convolution which segment is adapted for engagement with said means for interconnecting said spπngs, such that said terminal convolution remains free of said interconnecting means when said spnng is in said innerspπng assembly 8. An innerspring comprising: a plurality of helical springs each formed of a plurality of coil turns, said springs being organized into an array and defining a support surface to said innerspring, means for interconnecting said springs into said array, each said spring having a terminal convolution at each end of a body portion of said coil turns, and at least one offset segment formed on a coil tuπi of said body portion, said coil tuπi of said body portion having said offset segment being spaced from a respective one of said terminal convolutions, said offset segment being adapted for engagement with said means for interconnecting said springs in the innerspring assembly, such that said respective one terminal convolution remains free of said interconnecting means when said spring is in the innerspring assembly. 9. The innerspring of claim 8 wherein at least one offset segment is formed on a coil tuπi of said body portion at each end of said spring and spaced from a respective terminal convolution. 10. The innerspring of claim 9 wherein two offset segments are formed on opposite sides of a coil turn of said body portion at each end of said spring and spaced from a respective terminal convolution, said offset segments having straight portions which are generally tangential to and laterally outboard from a cylindrical shape generally defined by the turns of said body portion, said offset segments being located in substantially the same plane which is perpendicular to a longitudinal axis defined by said cylindrical shape. 1 1. The innerspring of claim 10 wherein each said coil tuπi having said offset segment thereon is the first tuπi inboard from a respective terminal convolution. 12. The innerspring of claim 10 wherein each said coil tuπi having said offset segments formed thereon is the second tuπ inboard from a respective terminal convolution, said terminal convolution and a first turn inboard from said terminal convolution being thereby free of said interconnecting means. 13. A mattress innerspring comprising: a plurality of helical springs each formed of a plurality of coil tuπis, said springs being organized into an array of orthogonal rows and columns and defining support surfaces to said innerspring on top and bottom sides thereof, means for connecting adjacent springs one to another into said array, each said spring having a terminal convolution at each end of said body portion, with two offset segments formed on a coil tuπ of said body portion at each end of said spring and spaced from a respective terminal convolution, said offset segments being on opposite sides of said body portion and having straight portions which are generally tangential to and laterally outboard from a cylindrical shape generally defined by the tuπis of said body portion, said offset segments being located in substantially the same plane which plane is normal to a longitudinal axis defined by said cylindrical shape, said offset segments being adapted for engagement with said means for interconnecting said springs in the innerspring, such that each said respective terminal convolution remains free of said interconnecting means when said spring is in the innerspring assembly. 14. The innerspring of claim 13 wherein said interconnecting means is a cross-helical spring, and wherein said springs are located In said array such that offset segments of springs in adjacent rows are parallel and close together in said array with said cross-helical spring surrounding and joining said close together offset segments along said rows. 15. The innerspring of claim 14 wherein βaid offset segments of adjacent springs are overlapped. 16. The innerspring of claim 14 wherein said springs each further include a third offset segment which is generally perpendicular to said other two offset segments, with said springs being further located in said array such that said third offset segments of springs in adjacent columns are parallel and close together in said array with a second cross-helical spring surrounding and joining said close together third offset segments along said columns. 17. An innerspring assembly comprising: an array of coil springs, said coil springs having an upper terminal portion, a lower terminal portion and a body portion therebetween, said coil springs being arranged in a generally side-by-side relation so that the upper terminal portions of said coil springs are generally coplanar in a first plane, and attachment means for attaching the body portions of adjacent coil springs to one another, the upper terminal portion of each coil spring being free to move axially of its respective body portion and independently of the axial movement of the upper terminal portions of adjacent coil springs. 18. The assembly of claim 17 wherein said upper terminal portions are not attached in any way to one another. 19* The assembly of claim 18 wherein said lower terminal portions are also generally coplanar in a second plane different from said first plane, said lower terminal portions also being unattached to one another. 20. The assembly of claim 19 wherein said coil springs are generally helical. in configuration and further wherein said upper terminal portions are convolutions of said helixes which have been formed so that at least 50% of each terminal convolution is disposed In said first plane. 21. The assembly of claim 20 wherein said body portions have turns which further define attachment convolutions the attachment convolutions of respective coil springs being arranged in a third common plane spaced from said first and second common planes, said attachment means attaching attachment convolutions of adjacent coil springs together. 22. The assembly of claim 20 wherein the distance between said first and second planes is at least one coil turn. 23. The assembly of claim 20 wherein said coil springs each define a set of at least two attachment convolutions spaced apart axially along said coil spring, with said coil springs arranged so that respective convolutions of each set are generally coplanar with the attachment convolutions of adjacent coil springs. 24. The assembly of claim 23 wherein the attachment convolutions of adjacent coil springs are in touching contact with one another. 25. The assembly of claim 24 wherein said attachment means comprises a cross-helical spnng. 26. The assembly of claim 24 wherein said attachment means comprises a clip. 27. The assembly of claim 24 wherein said attachment convolutions include first and second offset portions on opposite sides of said body portion, which offset portions are generally straight and generally parallel to each other, said first and second offset portions of adjacent coil springs overlapping one another, said attachment means comprising a plurality of cross-helical springs each coiled about respective pairs of βaid overlapping first and second offset portions. 28. The assembly of claim 27 wherein said attachment convolutions contain third offset portions located perpendicular to said first and second offset portions, said coil springs arranged so that the third offset portions of the coil springs on the periphery of said assembly define a perimeter, said assembly further including a border wire and a border wire helical spring coiled around said perimeter third offset portions and said border wire. 29. The assembly of claim 27 wherein said coil springs are arranged in a plurality of parallel rows and parallel columns whereby said assembly is generally rectangular in shape. 30. The assembly of claim 28 wherein βaid third offset portions of said coil springs each have a stepped segment formed thereon, said stepped segment having a major part that is substantially straight and spaced radially outwardly from the axis of said coil springs, short parts, extending from the ends of said straight part, said short parts joining with remaining straight segments of a respective offset portion, which remaining straight segments extend generally parallel to said straight part. 31 . The assembly of claim 17 wherein the upper terminal portion of each coil spring comprises a convolution of said coil spring and further wherein at least 80% of each upper terminal convolution is in said first plane. 32. The assembly of claim 31 wherein tuπis of βaid body portions of said coil springe define respective attachment convolutions arranged in a common attachment plane different from said first plane. 33. The assembly of claim 32 wherein said attachment convolutions include first and second offset portions on opposite sides of said body portion, which offset portions are generally straight and generally parallel to each other, the first and second offset portions of adjacent coil springs overlapping one another, βaid attachment means comprising a plurality of cross-helical springs coiled about said overlapping respective pairs of first and second offset portions. 34. In a pocketless innerspring assembly for use in a mattress comprising a plurality of coil springs defining upper and lower terminal convolutions and arranged in a generally side-by-side arrangement with at least some of the convolutions in adjacent coil springs overlapping one another and cross-helical springs coiled around the overlapping convolutions of adjacent coil springs to hold βaid coil springs together and thereby form said innerspring assembly, the improvement wherein βaid overlapping convolutions which are held together by sain cross- helical springs are spaced inboard from the upper terminal convolutions such that said upper terminal convolutions are unattached to one another and can move independently of one another in response to an applied pressure. 35. A method for making an innerspring assembly having a flexibility that is readily adjustable in manufacture comprising the steps of: providing a plurality of coil spring each having respective upper terminal portions, lower terminal portions and body portions therebetween, said body portions defining an attachment convolution for attaching adjacent coils to one another, arranging βaid plurality of coil springs in a generally side-by-side array with the terminal portions of βaid coil springs generally coplanar in respective first and second parallel planes and further so that the attachment convolutions of βaid coil springs are coplanar in an attachment plan different from said first and second planes, connecting adjacent coil springs in said array together to form an integral innerspring assembly from said plurality of coil springs, said coil βprings being connected to one another by attaching attachment convolutions of adjacent coil springs to one another, and adjusting the distance between said first plane and said attachment plane in manufacture to thereby vary said innerspring flexibility.

Inventors: FREEMAN BARRY WILLIAM, LANGER PAUL J, WAGNER ROBERT F, FREEMAN, BARRY, WILLIAM, LANGER, PAUL, J., WAGNER, ROBERT, F.
Applicants: OHIO MATTRESS CO, THE OHIO MATTRESS COMPANY LICENSING AND COMPONENTS
Application year: 1995
Main classification: A47C23
IPC codes: A47C23, A47C27, B21F33, F16F3