POSTURIZED BEDDING OR SEATING PRODUCT INCORPORATING BONNELL COIL SPRINGS WITH TAPERED MIDDLE PORTIONS

Field of the Invention

This invention relates to a posturized bedding or seating

product in which certain sections are firmer than other sections of the

product and the associated method of manufacturing such a product.

Background of the Invention

Conventional bedding or seating products have a spring core

made of a plurality of coil springs arranged into a matrix of rows and

columns. Each of the coil springs has an upper end turn, a lower end turn

and a plurality of central convolutions therebetween. The end turns may be

knotted or unknotted. Coil springs having knotted end turns are known as

Bonnell springs in the industry. The diameter of the end turns may be

identical to the diameter of the central convolutions of the coil spring.

Alternatively, the end turns of the coil springs may be of a larger or smaller

diameter than the central convolutions of the coil spring. In some coil

springs, the central convolutions taper from one end turn to the other. In

other coil springs the central convolutions taper to a smaller diameter and

then return to a larger diameter as they approach the end turns, thereby

creating an "hourglass" shape. Typically, the coil springs are of the same

height for ease of assembly.

The coil springs are usually connected or joined together by

securing the end turns of adjacent coil springs to each other using helical

lacing wire. The helical lacing wire encircles the end turns of adjacent coil

springs, thus securing adjacent rows or adjacent columns of coil springs

together. By lacing all of the coil springs together, a unitary spring core or

spring assembly is made. Often one or two generally rectangular border

wires are secured to the outermost coil springs of a spring core or spring

assembly.

The spring core is commonly covered on one or both surfaces

with padding and then wrapped in an upholstered material. Bedding or

seating products made in this manner using identical coil springs typically

have a uniform feel or firmness across the entire surface of the product

due, at least in part, to the coil springs being identical and oriented the

same direction within the spring core.

Other types of products are posturized, that is, different

sections or zones of the bedding or seating product have different levels of

firmness within the product. For example, the middle region of the

mattress, which typically supports a person's torso, often requires a firmer

less resilient support while other areas of the mattress which support the

feet and head of a person require less support.

One known method of posturizing a spring unit has been to

incorporate coil springs made of different gauge wire into the spring core.

For example, rows of coil springs within certain sections or zones of the

spring assembly are made of a heavier gauge wire than the springs

incorporated into rows of the other sections or zones of the spring

assembly. Patent No. 6,173,464 discloses this concept, albeit with

continuous bands of springs as opposed to individual springs. Due to the

fact that different coil springs must be incorporated into the assembled

spring core, the manufacturing cost of producing such a posturized product

may be relatively high and assembly may be difficult.

Therefore, there is a need for a posturized spring assembly and

associated method of manufacture which offers the advantages of

posturization of the spring assembly without the higher manufacturing

costs, production difficulties and inefficiencies associated with known

posturized spring assemblies.

Summary of the Invention

The present invention comprises a posturized bedding or

seating product made of identical coil springs and its associated method of

manufacture. The bedding or seating product comprises a posturized spring

assembly, one or more pads and an upholstered covering surrounding the

spring assembly and pad(s). The product is preferably two sided, but may

be one sided.

The spring assembly or spring core within the product

comprises a plurality of identical coil springs arranged in rows and columns

and joined together with helical lacing wires at the end turns of the coil

springs. Each of the coil springs comprises a first knotted end turn, a

second knotted end turn and a plurality of central convolutions between the

knotted end turns. In accordance with the practice of this invention, the

central convolutions of the spring are conically tapered in diameter from the

first knotted end turn to the second knotted end turn. Such springs are

hereinafter referred to as conically tapered coil springs and are to be

distinguished from cylindrical coil springs which have all of the central

convolutions of approximately the same diameter or hourglass-shaped

springs which have the central convolutions varying in diameter so as to

form an hourglass shape from top to bottom.

The bedding or seating product typically has a longitudinal

dimension and a transverse dimension, the longitudinal dimension being

greater than the transverse dimension. However, the longitudinal dimension

and transverse dimension may be identical in a square bedding or seating

product. In the invention, the helical lacing wires may extend longitudinally

or transversely, depending upon the desired effect.

At least one border wire may extend around the perimeter of

the spring assembly of the bedding or seating product and be secured to

select outermost coil springs. A first or lower border may be secured to the.

^" lower enα turns of the outermost or perimeter coil springs. A second or

upper border wire may be secured to the upper end turns of the outermost

or perimeter coil springs. Alternatively, either border wire may be secured to

intermediate convolutions of the outermost coil springs.

The spring core or assembly is divided into zones or sections of

differing firmness, each of the sections comprising a plurality of rows or a

plurality of columns of coil springs secured together. The zones or sections

may extend from side-to-side (transversely) or from end-to-end

(longitudinally) of the product.

Due to the conically tapered coil springs in one section, zone or

region of the spring core being oriented differently than the coil springs in

another section of the spring assembly, at least one section of the spring

assembly has a "softer" feel when a load is placed thereon than at least one

other section.

One aspect of the invention is a bedding or seating product

which includes a spring core having a plurality of identical conically tapered

coil springs. Each of the coil springs has a first knotted end turn, a second

knotted end turn, and a plurality of central convolutions between the

knotted end turns. The central convolutions taper in diameter from the first

knotted end turn to the second knotted end turn. The spring core is divided

into sections of differing firmness. All of the coil springs of at least one of

the sections have the first knotted end turn above the second knotted end

turn. All of the coil springs of at least one other section are inverted so as

to have the first knotted end turn below the second knotted end turn. The

bedding or seating product also includes padding located above the spring

core and an upholstered covering surrounding the padding and the spring

core.

Helical lacing wires join the coil springs, together and can join

them in adjacent rows or columns, i.e., extend laterally or longitudinally of

the product. In addition, in some embodiments, a border wire is secured to

some of the coil springs. The differing firmness sections can extend from

one side of the product to the other side of the product, or, can extend from

end-to-end in different embodiments. In some embodiments, the diameter

of the knotted end turns of the coil springs are identical and in others, they

may differ.

Another aspect of the invention is a method of manufacturing a

posturized bedding or seating product having sections of different firmness.

The method includes providing a plurality of identical coil springs arranged in

rows and columns. Each of the coil springs has a first knotted end turn, a

second knotted end turn and a plurality of central convolutions between the

knotted end turns. The central convolutions are tapered conically in

diameter from the first knotted end turn towards the second knotted end

turn. The method also includes arranging the coil springs into rows and

columns. The coil springs of several adjacent rows are oriented such that

the first knotted end turn is above the second knotted end turn, and the coil

springs of other adjacent rows are inverted and oriented such that the

second knotted end turn is above the first knotted end turn. The method

also includes joining the coil springs together with helical lacing wires.

Yet another aspect of the invention is a method of

manufacturing a posturized bedding or seating product having sections of

different firmness. The method includes providing a plurality of identical coil

springs arranged in rows and columns. Each of the coil springs has a first

knotted end turn, a second knotted end turn and a plurality of central

convolutions between the knotted end turns. The central convolutions taper

conically in diameter from the first knotted end turn towards the second

knotted end turn. The method also includes arranging the coil springs into

rows and columns. The coil springs of several adjacent columns or rows are

oriented such that the first knotted end turn is above the second knotted

end turn. The coil springs of other adjacent columns or rows are inverted

and oriented such that the second knotted end turn is above the first

knotted end turn. The method also includes joining the coil springs together

with helical lacing wires.

These and other features of the present invention will be more

readily apparent from the following drawings.

Brief Description of the Drawings

FIG. 1 is a perspective view of a posturized bedding product

made in accordance with the present invention comprising a spring assembly

made of identical coil springs surrounded by generally rectangular border

wires;

FIG. 2 is a perspective view of a coil spring made in accordance

with the present invention in a first orientation;

FIG. 3 is a perspective view of the coil spring of FIG. 2 oriented

in a second inverted orientation;

FIG. 4 is a diagrammatic top plan view of the spring core of the

spring assembly of FIG. 1 ;

FIG. 4A is a cross-sectional view taken along the line 4A-4A of

FIG. 4;

FIG. 5 is a diagrammatic top plan view of an alternative

embodiment of spring core assembly made in accordance with the present

invention;

FIG. 6 is a diagrammatic top plan view of an alternative

embodiment of spring core assembly made in accordance with the present

invention; and

FIG. 7 is a diagrammatic top plan view of an alternative

embodiment of spring core assembly made in accordance with the present

invention.

Detailed Description of the Drawings

Referring to the drawings, and particularly to FIG. 1 , there is

illustrated a bedding or seating product in the form of a mattress 10.

Although a mattress 10 is illustrated, the present invention may be used to

construct any bedding or seating product. The mattress 10 comprises a

spring assembly or core 12 having a generally planar top surface 14 in a top

plane P1 and a parallel generally planar bottom surface 16 in a bottom plane

P2. Covering pads 18 (only one being shown) may be located on the top

and bottom surfaces 14, 16 of the spring core assembly 12. The covering

pads 18 are usually formed from a cotton, felt, foam, or a synthetic fiber,

but other materials can be used in other embodiments. An upholstered

covering 20 or ticking encases the spring assembly 12 and the covering

pads 18.

The mattress 10 has a height H defined as the distance

between the top and bottom surfaces 14, 16 of the spring assembly 12.

Similarly, the mattress 10 has a transverse dimension or width W defined

between opposed side surfaces 22 and a longitudinal dimension or length L

defined as the distance between the opposed end surfaces 24 of the

mattress 10. The longitudinal dimension is illustrated as being larger than

the transverse dimension of the mattress 10, although it is within the

contemplation of the present invention that the longitudinal and transverse

dimensions be identical, such as in a square product.

The spring assembly or core 12 is divided into two sections 26,

28 in the embodiment illustrated in FIGS. 1 and 4. Any number of sections

readily apparent to those skilled in the art may be used in other

embodiments, such as those illustrated herein with respect to FIGS. 5, 6

and 7. In the embodiment illustrated in FIG. 1 , there is a first "soft" section

26 and a second "firm" section 28. The first section 26 is soft or has a

"soft" feel because the coil springs 30 are constructed and oriented such

that a predetermined amount of give or resilience exists within the springs

30. The second section 28 is a more firm section (firmer than first section

26) because the coil springs 30 are constructed and oriented such that a

predetermined amount of resilience exists within the coil springs 30. The

construction and orientation of the coil springs 30 are discussed in detail

with respect to FIGS. 2-7.

Referring now to FIG. 2, a single spring 30 of the spring

assembly 12 is illustrated. The coil spring 30 is usually formed from high

carbon steel of between twelve and three-fourths and fifteen and a half

gauge wire. However, those skilled in the art recognize that other gauges

and materials can be used. The spring 30 has a first knotted end turn 32

and a second knotted end turn 34. These types of springs are known as

"Bonnell" springs in the industry. The knotted end turns 32, 34 are formed

by bending a wire into a generally circular shape. The illustrated knotted

end turns 32, 34 have identical diameters, but other embodiments have

varying diameters. Positioned between the knotted end turns 32 and 34 is a

middle section 36. The middle section 36 includes a plurality of

convolutions that taper conically from one end of the middle section 36 to

the other. This conically-shaped middle section 36, which in the illustrated

embodiment comprises three full convolutions, has its largest diameter

convolution 37 connected directly to or terminating at the first end turn 32.

The smallest diameter convolution 37' is connected to the other or second

end turn 34 by a connector section of wire 39. The end of the wire

forming the end turn 32 terminates in a knot 38 that couples the end turn

32 to the next adjacent convolution and the end turn 34 terminates in a

knot 40 that couples end turns 34 to the connector section 39. The knots

38, 40 are formed by bending or wrapping an end portion of the length of

wire from which the spring is made around the convolution which is next

adjacent the end turns 32, 34. Positioning or orienting the springs 30 as

illustrated in FIG. 2 into a bedding or seating product results in providing

more give or more resilience (softer feel) to the top of the bedding or seating

product having springs so oriented as opposed to having the springs 30

inverted as illustrated in FIG. 3 because the larger turns or convolutions of

the middle section 30 of the spring are at the top of the product. When the

springs are inverted, the smaller diameter turns of the middle section 36 of

the spring 30 are at the top and the top therefore has a more firm feel and is

less resilient beneath the inverted spring when compressed from the top.

For example, in the embodiment illustrated in FIG. 1 , coil

springs 30 are placed inside the mattress 10 in different orientations. The

coil springs 30 of the first section 26 are oriented as shown in FIG. 2,

whereas the coil springs 30 of the second section 28 are oriented as shown

in FIG. 3. In the coil springs 30 of the first section 26, the first knotted end

turn 32 is located proximate to the generally planar top surface 14 of the

mattress 10. Accordingly, the convolutions of the middle section 36 taper

from a larger diameter to a smaller diameter as they move towards the

generally planar bottom surface 16. The larger convolutions located close to

the first knotted end turn 32 have a greater flexibility and deflect more than

the smaller convolutions positioned close to the second knotted end turn 34.

Accordingly, the first section 26 of the mattress 10 has more give and has a

softer- feel than the second section 28 of the mattress 10. As illustrated in

FIG. 1 , the springs 30 of the first section 26 of the product 10 are

positioned in this manner, providing a "soft" feel.

Referring to FIG. 3, like reference characters are used to denote

identical parts. The coil spring 30 is a spring identical to the coil spring 30

illustrated in FIG. 2 except that the position or orientation of the coil spring

30 has been inverted. The first knotted end turn 32 is now below the

second knotted end turn 34 in the illustration. The convolutions of the

middle portion 36 now taper from a large diameter to a smaller diameter as

they extend upwardly. Positioning the coil spring 30 as illustrated in FIG. 3

in the mattress 10 results in more firmness and less resilience in a portion

the bedding or seating product when the coil spring 30 is compressed from

the top.

For example, placing the spring 30 of FIG. 3 inside the mattress

10 of FIG. 1 with the second knotted end turn 34 proximate to the top

surface 14 of the mattress 10 provides a firmer top surface 14 than the

bottom surface 16. The second knotted end turn 34 has smaller diameter

convolutions positioned close to the knotted end turn 34 that will not

deflect as much as the larger diameter convolutions. Accordingly, the

mattress 10 will have a firmer feel. The second section 28 of the mattress

10 illustrated in FIG. 1 has springs 30 positioned in such a manner.

Referring now to FIG. 4, the spring core 12 of the mattress 10

of FIG. 1 is illustrated from a diagrammical top view. The mattress 10 of

FIG. 1 is commonly referred to as a "his and her" mattress. The "his and

her" name refers to the fact that there are two sections having different

levels of firmness. Therefore, a couple can choose a mattress and custom

design the levels of firmness to each of their personal preferences. The

mattress 10 is divided into the first section 26 and the second section 28.

The first section 26 has a soft feel, which is illustrated by the coil springs

30 having two closely spaced concentric circles representing the first

knotted end turn 32 and the larger diameter convolution 37 of the middle

portion 36 of a coil spring 30. In contrast, the second section 28 of the

mattress 10 has a "firm" feel (firmer than the first section 26) illustrated by

the springs 30 having two further spaced concentric circles representing the

second knotted end turn 34 and the smaller diameter convolution 37' of the

middle portion 36 of the coil spring 30.

All of the springs 30 are joined together using the helical lacing

wires 42. FIG. 4 illustrates the springs being laced together in columns that

run parallel to the length of the mattress 10 or from end-to-end. FIG. 4

illustrates a border wire 44 surrounding the spring assembly 12 and secured

to outermost coil springs 30 of the spring assembly 12, thereby providing

edge support to the spring assembly 12, as is known in the art.

FIG. 5 illustrates an identical mattress 10' to the one illustrated

in FIG. 4 except that the helical lacing wires 42' joining the springs 30

together extend in a transverse direction connecting adjacent rows, as

opposed to adjacent columns of springs 30, the helical lacing wires 42'

extending from side-to-side. In addition, FIG. 5 illustrates a border wire 44'

surrounding a spring assembly 12' and providing edge support to the spring

assembly 12'. The mattress 10' has a "soft" section 26' and a "firm"

section 28' due to the orientation of the coil springs 30, as described above.

FIG. 4A illustrates how the springs 30 are positioned along one

of the transversely extending rows of springs 30 illustrated in FIG. 4. The

first section 26 of the mattress 10 has springs 30 positioned so that the

first knotted end turn 32 is above the second knotted end turn 34. The first

knotted end turn 32 is also proximate to the top surface 14 of the mattress

10. Due to the springs 30 having this orientation or positioning, the first

section 26 has a soft feel. Conversely, the second section 28 has springs

30 inverted and positioned with the first knotted end turn 32 below the

second knotted end turn 34. The second knotted end turn 34 and the

smaller convolutions of the middle portions 36 of the springs 30 are

proximate to the top surface 14 of the mattress 10. This positioning results

in a firmer feel in the second section 28 compared to the first section 26.

FIG. 6 illustrates an alternate embodiment of a mattress 46

that has three sections of differing firmness. Identical reference characters

are used to describe identical parts. The three sections alternate moving

along the longitudinal dimension or length of the mattress 46. Adjacent

columns of springs 30 also joined together using helical lacing wires 42",

the helical lacing wires 42" extending along the longitudinal dimension of

the mattress 46 (from end-to end). The first section 48 is a soft section.

This soft section 48 as illustrated includes five transversely extending rows

along the longitudinal dimension. This provides a soft area that will support

either the head and shoulder or the feet and legs of a person lying on the

mattress. The first section 48 therefore does not need as much resilience

because the first section 48 is not supporting the heavier parts of the body.

The second section 50 is a firmer section that includes six transversely

extending rows of springs as illustrated. The second section 50 is firmer

than the first section 48 to provide support for the upper and lower torso,

the heavier parts of the body. Therefore, the second section 50 needs

more resistance to support those heavy parts of the body. The third section

52 is identical to the first section, positioned only on the other end of the

mattress 46. Together, the first, second and third sections 48, 50, and 52

provide a posturized mattress 46 that increases the support where it is

needed most, in the middle of the product or mattress.

Referring now to FIG. 7, an alternative embodiment of a

mattress 54 is illustrated. Identical reference characters denote identical

parts. In this embodiment, the three sections are arranged alternatively

along the transverse dimension or width of the mattress 54. The first

section 56 is a firm section along the outer portion of the mattress 54. The

second section 58 is a softer section arranged in the central portion of the

mattress 54. In addition, the third section 60 is another firmer section.

This positioning creates a soft central section 58 surrounded by the firmer

sections 56 and 60. A consumer that desires a soft area to sleep in with

outer support would prefer this arrangement.

Although I have described several preferred embodiments of

our invention, I do not intend to be limited except by the scope of the

following claims.

I CLAIM: