Title:

Method for making a cushion

Document Type and Number:

United States Patent Application 20050017396

Kind Code:

Abstract:

A method for making a cushioning element including forcing molten gel through an extrusion die, and cutting the gel as it exits the die.

Representative Image:

Inventors:

Pearce, Tony M. (Alpine, UT, US)
Pearce, Terry V. (Alpine, UT, US)

Plaque It!

PRIORITY

This patent application is a divisional of U.S. patent application Ser. No. 10/059,101 filed on Nov. 8, 2001, now ______, which is a continuation-in-part of Untied States patent application Ser. No. 09/303,919 filed May 3, 1999, now U.S. Pat. No. 6,413,458, which is a continuation-in-part of U.S. patent application Ser. No. 08/968,750 filed on Aug. 13, 1997, now U.S. Pat. No. 6,026,527, which is a continuation-in-part of U.S. patent application Ser. No. 08/601,374 filed on Feb. 14, 1996, now U.S. Pat. No. 5,749,111, which is a continuation-in-part of U.S. patent application Ser. No. 08/783,413 filed on Jan. 10, 1997, now U.S. Pat. No. 5,994,450 and priority to and benefit of each of the foregoing is claimed. This patent application is also a divisional of U.S. patent application Ser. No. 10/059,101 filed on Nov. 8, 2001, now ______, which is a continuation-in-part of U.S. patent application Ser. No. 09/932,393 field on Aug. 17, 2001, now ______, which is a continuation-in-part of U.S. patent application Ser. No. 09/303,979 filed on May 3, 1999, now U.S. Pat. No. 6,413,458, which claims benefit of U.S. Provisional Patent Application Ser. No. 60/226,726 filed on Aug. 18, 2000, and priority to and benefit of each of the foregoing is claimed.

BACKGROUND

This subject matter herein invention relates to the field of cushioning devices, gelatinous elastomers and devices made therefrom. More particularly, some embodiments relate to a cushion or cushioning device made in whole or in part of gelatinous elastomer, gelatinous visco elastomer, and the elastomers themselves, methods for making any of the foregoing, and structures made from the foregoing and other cushioning structures and other devices including gelatinous elastomers.

SUMMARY

Various cushioning devices and materials are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts one embodiment of the cushion as part of an office chair.

FIG. 2 depicts one embodiment of the cushion including its cushioning element and cover.

FIG. 3 depicts a cutaway of one embodiment of the cushion of FIG. 1 at 3-3.

FIG. 4 depicts a mold which may be used to manufacture one embodiment of the cushion.

FIG. 5 depicts an alternative mold for manufacturing one embodiment of the cushion.

FIG. 6 depicts a cross sectional view of a cushion manufactured using the mold of FIG. 5.

FIG. 7 depicts an isometric view of an alternative embodiment of the cushion.

FIG. 8 depicts a top view of an alternative embodiment of the cushion.

FIG. 9 depicts an isometric view of an alternative embodiment of the cushion.

FIG. 10 depicts a top view of an alternative embodiment of the cushion.

FIG. 11 depicts a cross sectional view of a column of an example cushion during buckling.

FIG. 12 depicts a cross sectional view of a column of an example cushion during another mode of buckling.

FIG. 13 depicts forces in play as an example cushion buckles.

FIG. 14 depicts an alternative structure for a column and its walls.

FIG. 15 depicts a cross section of a cushion using alternating stepped columns.

FIG. 16 depicts am alternative embodiment of the cushioning element having gas bubbles within the cushioning media.

FIG. 17 depicts an example cushion in use with a combination base and container.

FIG. 18 depicts an example cushion having side wall reinforcements to support the cushioning element.

FIG. 19 depicts an example cushioning element having a girdle or strap about its periphery to support the cushioning element.

FIG. 20 depicts an example cushioning element with closed column tops and bottoms and fluid or other cushioning media contained within the column interiors.

FIG. 21 depicts an example cushioning element with firmness protrusions placed within the column interiors.

FIG. 22 is a frontal perspective view of an embodiment of the cushioning element which include multiple individual cushioning units.

FIG. 23a is a frontal perspective view of an embodiment of the cushioning element in which a first cushioning medium is contained within a second cushioning medium.

FIG. 23b is a cross section taken along line 23b-23b of FIG. 23a.

FIG. 23c is a frontal perspective view of an alternate configuration of the embodiment shown in FIG. 23a.

FIG. 23d is a cross section taken along line 23d-23d of FIG. 23c.

FIG. 24a is a frontal perspective view of an embodiment of the cushioning element in which the! outer surfaces of the cushioning medium are covered with a coating.

FIG. 24b is a cross section taken along line 24b-24b of FIG. 24a.

FIG. 25a is a perspective view of an embodiment of the cushioning element, wherein the cushion includes multiple sets of parallel columns and wherein each column intersects no columns of another parallel column set or columns of only one other set.

FIG. 25b is a cross section taken along line 25b-25b of FIG. 25a.

FIG. 25c is a cross section taken along line 25c-25c of FIG. 25a.

FIG. 25d is a perspective view of an alternative configuration of the embodiment shown in FIG. 25a, wherein each column may intersect columns of any number of the other parallel column sets.

FIG. 25e is a cross section taken along line 25e-25e of FIG. 25d.

FIG. 25f is a cross section taken along line 25f-25f of FIG. 25d.

FIG. 26 is a frontal perspective view of an embodiment of the cushioning element wherein the cushion has multiple sets of parallel narrow columns.

FIG. 27a is a frontal perspective view of an embodiment of the cushioning element which includes multiple sets of parallel columns and cavities formed in the column walls.

FIG. 27b is a cross section taken along line 27b-27b of FIG. 27a.

FIG. 27c is a cross section taken along line 27c-27c of FIG. 27a.

FIG. 28 is a frontal perspective view of an embodiment of the cushioning element which has a contoured surface and includes columns of more than one height.

FIG. 29 is a frontal perspective view of an embodiment of the cushioning element wherein the cushioning medium is foamed.

FIG. 30a is a frontal perspective view of an embodiment of the cushioning element wherein the column walls are formed from numerous short tubular pieces, which create voids in the column walls.

FIG. 30b is a frontal perspective view of an alternative configuration of the cushioning element shown in FIG. 30a, wherein the column walls include voids created by extracting space consuming objects therefrom following molding of the cushioning medium.

FIG. 31a depicts a carbon atom and its covalent bonding sites.

FIG. 31b depicts a hydrogen atom and its covalent bonding site.

FIG. 31c depicts a four carbon hydrocarbon molecule known as butane.

FIG. 32a depicts a triblock copolymer useful in a cushioning medium.

FIG. 32b depicts the triblock copolymer of FIG. 32a in a relaxed state.

FIG. 33a depicts the chemical structure of a styrene molecule.

FIG. 33b depicts the chemical structure of a benzene molecule.

FIG. 33c depicts the chemical structure of an aryl group.

FIG. 33d depicts, the chemical structure of an-enyl group.

FIG. 33e depicts the chemical structure of an ethenyl group.

FIG. 33f depicts the chemical structure of a propenyl group.

FIG. 34a depicts a midblock (B) of the triblock copolymer of FIG. 32a. 8

FIG. 34b depicts an endblock (A) of the triblock copolymer of FIG. 32a.

FIG. 34c depicts the weak bonding between the monomer unites of one or more midblocks (B) of the triblock copolymer of FIG. 32a.

FIG. 34d depicts an endblock (A) of the triblock copolymer of FIG. 32a, showing the endblock (A) in a relaxed state.

FIG. 35a depicts the chemical structure of hydrocarbon molecules known as alkanes.

FIG. 35b depicts the chemical structure of hydrocarbon molecules known as alkenes.

FIG. 35c depicts the chemical structure of hydrocarbon molecules known as alkynes.

FIG. 35d depicts the chemical structure of a hydrocarbon molecule known as a conjugated diene.

FIG. 35e depicts the chemical structure of a hydrocarbon molecule known as an isolated diene.

FIG. 36a depicts the chemical structure of a poly(ethylene/butylene) molecule.

FIG. 36b depicts the chemical structure of a poly(ethylene/propylene) molecule.

FIG. 36c depicts the chemical structure of a 1,3-butadiene molecule.

FIG. 36d depicts the chemical structure of an isoprene molecule.

FIG. 37a depicts polystyrene-poly(ethylene/butylene)-polystyrene.

FIG. 37b depicts polystyrene-poly(ethylene/propylene)-polystyrene.

FIG. 37c depicts polystyrene-polybutadiene-polystyrene.

FIG. 37d depicts polystyrene-polyisoprene-polystyrene.

FIG. 37e depicts polystyrene-poly(isoprene+butadiene)-polystyrene.

FIG. 37f depicts polystyrene-poly (ethylene/butylene+ethylene/propylene)-polystyrene.

FIG. 38a depicts the chemical structure of polystyrene-poly(ethylene/butylene+ethylene/propylene)-polys tyrene.

FIG. 38b depicts the group of the triblock copolymers of FIG. 321a, showing weak attraction of the endblocks to each other.

FIG. 39a illustrates plasticizer association with the group of triblock copolymers of FIG. 38b.

FIG. 39b illustrates the lubricity theory of plasticization, showing two midblocks (B) moving away from each other.

FIG. 39c illustrates the lubricity theory of plasticization, showing two midblocks (B) moving toward each other.

FIG. 39d illustrates the lubricity theory of plasticization, showing two midblocks (B) moving across each other.

FIG. 39e illustrates the gel theory of plasticization, showing a weak attraction between two midblocks (B) when plasticizer is not present.

FIG. 39f illustrates the gel theory of plasticization, showing a plasticizer molecule breaking the weak attraction of FIG. 39e.

FIG. 39g illustrates the mechanistic theory of plasticization, showing an equilibrium of plasticizer breaking the weak attraction of midblocks (B) for each other.

FIG. 39h illustrates the free volume theory of plasticization, showing the free space associated with a midblock (B).

FIG. 39i illustrates the theory of FIG. 39h, showing that as small plasticizer molecules are added, the free space in a given area increases.

FIG. 39j illustrates the theory of FIG. 39h, showing the even small plasticizers provide an even greater amount of free space.

FIG. 40a depicts the use of an extruder to perform a method for foaming gel cushioning media.

FIG. 40b depicts the use of an injection molding machine to perform a method for foaming a gel cushioning media.

FIG. 41 depicts an embodiment of a cushioning element, wherein a plurality of tubes are bonded together to form the cushion.

FIG. 42 depicts a method for bonding the individual tubes of FIG. 41 together to form the cushioning element shown therein.

FIG. 43 depicts cut foam bun of step 1.

FIG. 44 depicts cut foam bun of step 2.

FIG. 45 depicts cut foam bun of step 3.

FIG. 46 depicts bonded foam of step 4.

FIG. 47 depicts insertion of side support pieces of step 5.

FIG. 48 depicts top view of bottom core piece.

FIG. 51 depicts cut foam bun of step 1.

FIG. 52a depicts separated foam of step 2.

FIG. 52b depicts aligned foam of step 3.

FIG. 53 depicts bonded foam of step 4.

FIG. 54 depicts compressed foam rail.

FIG. 55 depicts foam and gellycomb cross-section.

FIG. 56 depicts foam and gellycomb with pillow-top layer in cross-section.

FIG. 57 depicts foam and gellycomb with two pillow-top layers in cross-section.

FIG. 58 depicts foam and gellycomb cross-section.

FIG. 59 depicts foam and gellycomb with gellycomb comfort layer cross-section.

FIG. 60a depicts side view with foam inserted.

FIG. 60b depicts side view of foam construction.

FIG. 60c depicts front view of foam construction.

FIG. 61 depicts foam insertion of step 1.

FIG. 62 depicts a cut-away view of foam.

FIG. 63 depicts gellycomb pillow-top layer.

FIG. 64 depicts gellycomb pillow-top layer with two layers.

FIG. 65 depicts foam construction.

FIG. 66 depicts foam construction.

FIG. 67a depicts the no tool assembly.

FIG. 67b depicts the no tool assembly of step 1.

FIG. 67c depicts folded down sides of step 2.

FIG. 67d depicts snapped corners of step 3.

FIG. 67e depicts loam construction.

FIG. 68a depicts flat construction.

FIG. 68b depicts folded down construction.

FIG. 69a depicts top view.

FIG. 69b depicts front view.

FIG. 69c depicts end view.

FIG. 70 depicts quilted top with fiber and gel elastomer layer.

FIG. 71 depicts quilted top with fiber and two gel elastomer layers.

FIG. 72 depicts quilted top with fiber and foam and thicker gel elastomer layer.

FIG. 73 depicts quilted top with fiber and one thin gel elastomer layer and one thick gel elastomer layer.

FIG. 74 depicts quilted top with fiber, two thin gel elastomer layers and one thick gel elastomer layer.

FIG. 75 depicts quilted top with fiber, one thin gel elastomer layer, and polyurethane foam.

FIG. 76 depicts quilted top with fiber, two thin gel elastomer layers, and polyurethane

FIG. 77 depicts quilted top with fiber, one thin gel elastomer layer, and high-grade visco-foam.

FIG. 78 depicts quilted top with fiber, one thin gel elastomer layer, and spring unit.

FIG. 79 depicts quilted top with fiber, two thin gel elastomer layers, and spring unit.

FIG. 80 depicts quilted top with fiber and foam, thick gel elastomer layer, and spring unit

FIG. 81 depicts quilted top with fiber, thin gel elastomer layer, and latex foam.

FIG. 82 depicts quilted top with fiber, latex topper, and thick gel elastomer layer.

FIG. 83 depicts quilted top with fiber, latex foam, and thick gel elastomer layer.

FIG. 84 depicts quilted top with fiber, polyurethane foam, and thick gel elastomer layer.

FIG. 85 depicts quilted top with fiber, pillow-soft polyurethane foam, and thick gel elastomer.

FIG. 86 depicts inserted molten material.

FIG. 87 depicts pearlized chintz quilt with foam and fiber; Intellifoam; and non-skid fabric.

FIG. 88 depicts pearlized chintz pillow-top with foam convoluted foam and fiber; Intelli-foam; and non-skid :fabric.

FIG. 89 depicts Belgian damask quilt with foam and fiber; SuperSoft latex; Intellifoam; and Belgian damask tick.

FIG. 90 depicts Belgian damask quilt with foam and fiber; SuperSoft Latex; Intellifoam; Firmsoft; and Belgian damask tick.

FIG. 91 depicts Belgian damask quilt with Supersoft fiber; SuperSoft latex; IntelLatex; Intelli-loam; and Belgian damask tick.

FIG. 92 depicts Belgian damask quilt with foam and fiber; Intelli-Gel; and Belgian damask: tick.

FIG. 93 depicts Belgian damask quilt with foam and fiber; Intelli-foam; Intelli-Gel; and Belgian Damask Tick.

FIG. 94 depicts pearlized chintz quilt with foam and fiber; Intelli-foam;

- springs; and non-skid fabric.

FIG. 95 depicts Belgian damask quilt with Supersoft fiber; IntelLatex;

- springs; and Belgian Damask tick.

FIG. 96 depicts stretch knit cover; Memory-foam; and Intelli-foam.

FIG. 97 depicts stretch knit cover; SuperSoft latex; and IntelLatex.

DETAILED DESCRIPTION

Configuration of the Cushions

FIG. 1 depicts a cushioned object 101, in this instance a human being, atop of a piece of furniture 102, in this instance a chair, which includes the cushion 103. Although in this embodiment, the cushion 103 is depicted as part of an office chair, the cushion may be used with many types of products, including furniture such as sofas, love seats, kitchen chairs, mattresses, lawn furniture, automobile seats, theatre seats, padding found beneath carpet, padded walls for isolation rooms, padding for exercise equipment, wheelchair cushions, bed mattresses, and others.

Referring to FIG. 2, the cushion 103 of FIG. 1 is depicted in greater detail. The cushion 103 includes a cover 204. An example cover is a durable and attractive fabric, such as nylon, cotton, fleece, synthetic polyester or another suitable material which may be stretchable and elastic and which readily permits the flow of air through it to enhance ventilation of a cushioned object. Within the cover 204, a cushioning element 205 is to be found. As can be seen from FIG. 2, the cushioning element 205 comprises a cushioning media of a desired shape. In the embodiment depicted, the cushioning element 205 includes gel cushioning media formed generally into a rectangle with four sides, a top and a bottom, with the top and bottom being oriented toward the top and bottom of the page, respectively. The cushioning element has within its structure a plurality of hollow columns 206. As depicted, the hollow columns 206 contain only air. The hollow columns 206 are open to the atmosphere and therefore readily permit air circulation through them, through the cover 204 fabric, and to the cushioned object. The columns 206 have column walls 207 which in the embodiment depicted are hexagonal in configuration. The total volume of the cushioning element may be occupied by not more than about 50% gel cushioning media, and that the rest of the volume of the cushioning element will be gas or air. The total volume of the cushioning element may be occupied by as little as about 9% cushioning media, and the rest of the volume of the cushion will be ;gas or air. This yields a lightweight cushion with a low overall rate of thermal transfer and a law overall thermal mass. It is not necessary that this percentage be complied with in every instance.

Referring to FIG. 3, a cushioned object 101, in this instance a human being, is depicted being cushioned by the cushion 103 which includes cushioning element 205 within cover 204. Also visible is a cushion base 301 of a rigid material such as wood, metal, plastic on which the cushioning element 205 rests. The cushioning element 206 includes hollow columns 206 with walls 207. It can be seen that beneath the most protruding portion of the cushioned object, in this instance a hip bone 302, the hollow columns 303 have walls 304 which have partially or completely buckled in order to accommodate the protuberance 302 and avoid creating a high pressure point below the protuberance 302 in response to the compressive force exerted by the cushioned object. Buckled columns offer little resistance to deformation, thus removing pressure from the hip bone; area. It can also be seen that in portions of the cushioning element 205 which are not under the protuberance 302, the cushioning media which forms the walls 304 of the hollow columns 303 has compressed but the columns 303 have not buckled, thus loading the cushioned object across the broad surface area of its non-protruding portions. The cushion is yieldable as a result of the compressibility of the cushioning media and the bucklability of the columns (or column walls). The cushion 103 is depicted as having been manufactured using the mold depicted in FIG. 4. It can be seen from this cushion's response to a compressive force exerted by the cushioned object that the cushion and the cushioning element are adapted to have a cushioned object placed on top of them.

Referring to FIG. 6, a cross section of an alternative embodiment is depicted. The cushioning element 601 includes cushioning media 604 (which may be a gel cushioning media) which form walls 605 for columns 602, 603. It can be seen that the columns 602 and 603 are oriented into a group protruding from the top of the cushioning element 601 down into the cushioning media 604 but not reaching the bottom of the cushioning element of which column 602 is a member, and a group protruding from the bottom of the cushioning element 601 into the cushioning element 601 but not reaching the top of the cushioning element 601 of which column 602 is a member. This yields a generally firmer cushion than that shown in some other figures. This cushion would be manufactured by the mold depicted in FIG. 5.

Referring to FIG. 7, an alternative embodiment of a cushioning element 701 is depicted. The cushioning element includes cushioning media 702, columns 703 and column walls 704. The columns depicted in FIG. 7 are square in a cross section taken orthogonal to their longitudinal axis, in contrast to the columns of FIG. 2 which are hexagonal in a cross section taken orthogonal to their longitudinal axis. It is also of note that in FIG. 7, the columns 703 are arranged as an n×m matrix with each row and each column of columns in the matrix being aligned perfectly adjacent to its neighbor, with no offsetting. Exemplary sizing and spacing of columns would include columns which have a cross sectional diameter taken Referring to FIG. 8, a top view of an alternative cushioning element 801 is depicted. The cushioning element 801 includes cushioning media 802 which forms column walls 804, columns 803 and an exterior cushioning element periphery 805. It can be seen that the columns 803 of FIG. 8 are arranged in offset fashion with respect to some of the columns to which they are adjacent. A myriad of column arrangements are possible, from well-organized arrangements of the columns to a random columnar arrangement. The columns may be arranged so that the total volume of gel cushioning media 802 within the volume of space occupied by the cushioning element 801 is minimized. This results in a lightweight cushion. To that end, the columns 803 may be arranged in close proximity to each other in order to minimize the thickness of the column walls 804. This will result in a lighter cushion and a cushion that will yield to a greater extent under a cushioned object of a given weight than a similar cushion with thicker column walls 804.

Referring to FIG. 9, an alternative cushioning element 901 is depicted with cushioning media 902, columns 903, column walls 904 and outer periphery 905 of the cushioning element 901 being shown. The columns 902 depicted are round in a cross section taken orthogonal to their longitudinal axes. The reader should note that it may be desirable to include a container or side walls which will contain the outer periphery 905 of the cushioning element. For example, in FIG. 9, a rectangular box with interior dimensions just slightly larger than the exterior dimensions of the cushioning element 901 could be employed. Or, as shown in FIG. 1, the side walls of the cover 204 could be rigid, such as by the use of plastic inserts. The effect of rigid side walls or a rigid container for a cushioning element is that when a cushioned object is placed on the cushioning element, the cushioning media will not be permitted to bulge outward at the cushioning element outer periphery. By preventing such outward bulging, greater cushion stability is achieved and a more direct (i.e. in a direction parallel to the longitudinal axis of a column, which in most of the figures, such as FIG. 3, is assumed to be in the direction of the Earth's gravity but which may not always be so) movement or descent of the cushioned object into the cushion is achieved. A direct movement or descent of a cushioned object into the cushion (i.e. parallel to the longitudinal axes of the columns) is desired because the column walls are configured to absorb weight and cushion the cushioned object, or, if the load under a protuberance gets high enough, by buckling of the columns. If a cushioned object travels a substantial distance sideways in the cushion, the hollow portion of the columns may be eliminated by opposing column walls collapsing to meet each other rather than either substantially compressing the cushioning media or by buckling as depicted in FIGS. 13 and 14. This would not provide the desired cushioning effect as it would result in collapsed columns within the cushion (rather than buckled columns), and the cushion would have little more cushioning effect than a solid block of the cushioning media without the columns.

Referring to FIG. 10, an alternative embodiment of the cushion 1001 is depicted. The cushion 1001 includes gel cushioning media 1002 in the form of an outer cushion periphery 1003, and column walls 1004 which form triangular hollow columns 1005. The reader should note that the columns of the various figures are merely illustrative, and in practice, the columns could be triangular, rectangular, square, pentagonal, hexagonal, heptagonal, octagonal, round, oval, n-sided or any other shape in a cross section taken orthogonal to the longitudinal axis of a column. The periphery of the cushioning element may also be triangular, rectangular, square, pentagonal, hexagonal, heptagonal, octagonal, round, oval, heart-shaped, kidney-shaped, elliptical, oval, egg-shaped, n-sided or any other shape.

FIG. 11 depicts a column 1101 including column walls 1102 and 1103 and column interior 1104. The column 1101 has a longitudinal axis 1105 which can be oriented in the cushion parallel to the direction of the longitudinal axis of a column which should be the direction that the cushioned object sinks into the cushion. Thus, the column top 1106 is at the side of the cushion that contacts the cushioned object, and the column bottom 1107 is at the side of the cushion that typically faces the ground and will rest on some sort of a base. Another way of describing this with respect to the longitudinal axis of each column is that the column top is at one end of the longitudinal axis of a column and the column bottom is at the other end of the longitudinal axis of a column. When an object to be cushioned is placed onto a cushion which contains many such columns 1101, such as is shown in FIG. 3, a depressive force 1108 is applied to the cushion and to the column 1101 by the cushioned object. Because the cushion is expected to rest on some type of supporting surface, such as a base, a reaction force 1109 is provided by -the supporting surface. The cushion, including the column 1101, yields under the weight of the cushioned object. This yielding is a result of compression of the cushioning media and, if the load under a protruding portion of the cushioned object is high enough, by buckling or partial buckling of the columns 1101. From FIG. 11, it can be seen that the depicted column 1101 buckles because the flexible cushion walls 1102 and 1103 buckle outward around the periphery of the column, as depicted by cross-sectional points 1110 and 1111. In other words, the column walls buckle radically outward orthogonally from the longitudinal axis of the column. This permits the column 1101 to decrease in total length along its longitudinal axis 1108 and thereby conform to the shape of protuberances on a cushioned object. Since buckled columns carry comparatively little load, this results in a cushion that avoids pressure peaks on the cushioned object.

FIG. 12 depicts a column 1201 including column walls 1202 and 1203 and column interior 1204. The column 1201 has a longitudinal axis 1205 which may be oriented in the , cushion parallel to the direction of movement of a cushioned object sinking, into the cushion. Thus, the column top end 1206 is at the side of the cushion that contacts the cushioned object, and the column bottom end 1207 is at the side of the cushion that typically will rest on some sort of a base. When an object to be cushioned is placed against a cushion which contains numerous columns 1201, such as is shown in FIG. 3, a depressive force 1208 is applied to the cushion and to the column 1201 by the cushioned object. Because the cushion is expected to rest on some type of supporting surface, such as a base, a reaction force 1209 is provided by the supporting surface. The cushion, including the column 1201, yields under the weight of the cushioned object. This yielding is a result of compression of the cushioning media and, if the load under a protruding portion of the cushioned object is high enough, by buckling or partial buckling of the columns. From FIG. 12, it can be seen that the depicted column 1201 buckles because the flexible cushion wall 1202 buckles outward from the column center or orthogonal away from the longitudinal axis of the column at point 1210, while cushion wall 1203 buckles inward toward the column center or orthogonal toward the longitudinal axis of the column at points 1211. This buckling action causes the column 1201 to decrease in total length along its longitudinal axis 1208 and thereby conform to the shape of protuberances on a cushioned object. Point 1210 is depicted buckling outward (away from the center of the column) and point 1211 is depicted as buckling inward (toward the center of the column). Alternatively, both points 1210 and 1211 could buckle inward toward the center of the column or both could buckle outward. Since buckled columns carry comparatively little load, this results in a cushion that avoids pressure peaks on the cushioned object. Buckling of a column permits the column to decrease in total length along its longitudinal axis and thereby conform to the shape of protuberances on a cushioned object. This results in a cushion that avoids pressure peaks on the cushioned object. It should be noted by the reader that the columns 1101 and 1201 depicted in FIGS. 11 and 12 are hollow columns which have interiors completely open to the atmosphere and which permit air to travel through the columns to enhance ventilation under the cushioned object. It is also of note that the column 1201 of FIG. 12 has column walls 1202 and 1203 that include fenestrations 1210 (which may be holes or apertures in the column walls) that permit the flow of air between adjacent columns, providing an enhanced ventilation effect. Fenestrations are also useful for reducing the weight of the cushioning element. The greater the size and/or number of fenestrations in column walls, the less the cushion weighs. The fenestrations or holes 1210 in the column walls could be formed by punching or drilling, or they could be formed during molding of the cushioning element.

FIG. 13 depicts an alternative column 1301 including column walls 1302 and 1303 and a column interior 1304. The column 1301 has a longitudinal axis 1305 which, in the cushion, may be oriented parallel to the direction in which the cushioned object is expected to sink into the cushion. Thus, the column top end 1306 is at the side of the cushion that contacts the cushioned object, and the column bottom end 1307 is at the side of the cushion that typically faces some sort of a base. When an object to be cushioned is placed onto a cushion which contains column 1301, such as is shown in FIG. 3, a depressive force 1308 is applied to the cushion and to the column 1301 by the cushioned object. Because the cushion is expected to rest on some type of supporting surface, such as a base, a reaction force 1309 is provided by the supporting surface. The cushion, including the column 1301, yields under the weight of the cushioned object. This yielding is a result of compression of the cushioning media and, if the load under a protruding portion of the cushioned object is high enough, by buckling or partial buckling of the columns. From FIG. 13, it can be seen that the depicted column 1301 buckles because the flexible cushion walls 1302 and 1303 buckle outward from the column center or orthogonal away from the longitudinal axis 1305 of the column at points 1311 and 1310. This buckling action allows the column 1301 to decrease in total length along its longitudinal axis 1305 and thereby conform to the shape of protuberances on a cushioned object.

In the embodiment depicted, the column 1301 is a sealed column containing air or an inert gas within its interior 1304. Thus, as the column 1301 decreases in length along its longitudinal axis, the gas within the column interior 1304 tends to support the column top end 1306 and resist the downward movement of the cushioned object. This yields a firmer cushion. Alternatively, open or closed cell (or other) foam or fluid cushioning media could be provided within the interior of the columns or within some of them in order to increase the firmness of the cushion.

FIG. 14 depicts an alternative embodiment of the column. The column 1401 depicted has column walls 1402 and 1403 and a column interior 1404. The column interior 1404 is open at column top end 1405 and at column bottom end 1406 to permit air to pass through the column 1401. Column 1401 has walls 1402 and 1403 which are thicker at their bottom end 1406 than at their top end 1405, imparting cushions which include such columns with a soft cushioning effect when cushioning an object that sinks into the cushion to only a shallow depth, but progressively providing firmer cushioning the deeper the cushioned object sinks. This configuration of column 1401 permits the construction of a cushion which accommodates cushioned objects of a very wide variety of weight ranges. Alternatively, the column walls could be thicker at the top than at the bottom, the column walls could be stepped, or the column walls could have annular or helical grooves in them to facilitate buckling under the load of a cushioned object. Additionally, the column interior could be of a greater interior dimension orthogonal to its longitudinal axis at one end than at the other. Or the columns could be of varying dimension and shape along their longitudinal axes.

FIG. 15 depicts a cross section of a cushioning element using alternating stepped columns. The cushioning element 1501 has a plurality of columns 1502 each having a longitudinal axis 1503, a column top 1504 and a column bottom 1505. The column top 1504 and column bottom 1505 are open in the embodiment depicted, and the column interior or column passage 1506 is unrestricted to permit air flow through the column 1502. The column 1502 depicted has side walls 1507 and 1508, each of which has three distinct steps 1509, 1510 and 1511. The columns are arranged so that the internal taper of a column due to the step on its walls is opposite to the taper of the next adjacent column. This type of cushioning element could be made using a mold similar to that depicted in FIG. 4.

FIG. 16 depicts an alternative embodiment of a cushioning element 1601. The cushioning element 1601 has a plurality of columns 1602, 1603 and 1604, each having a column interior 1605, 1606 and 1607, and column walls 1608, 1609, 1610 and 1611. The column walls are made from cushioning; media, such as the example soft gels herein. In the embodiment of the cushioning element 1601 depicted, the cushioning media 1612 has trapped within it a plurality of gas bubbles 1613, 1614 and 1615. When a soft gel cushioning medium is used, since the gel is not flowable at the temperatures to which the cushion is expected to be exposed during use, the bubbles remain trapped within the cushioning medium. The use of bubbles within the cushioning medium reduces the weight of the cushion and softens the cushion to a degree which might not otherwise be available. Bubbles may be introduced into the cushioning medium by injecting air, another appropriate gas, or vapor into the cushioning medium before manufacturing the cushioning element, by vigorously stirring the heated, flowable cushioning medium before it is formed into the shape of a cushion, or by utilizing a cushioning medium of a composition that creates gas or boils at the temperatures to which it is subjected during the manufacture of a cushioning element. Blowing agents, some of the uses of which are described in detail below in connection with the disclosure of the gel material, are also useful for introducing gas bubbles into the cushioning medium. Microspheres, which we also discussed in greater detail below, are also useful for introducing gas pockets into the cushion medium.

FIG. 17 depicts an embodiment of the cushioning element which has cushioning medium, solid exterior walls 1703 and 1704, a plurality of columns 1705 and column walls 1706 forming the columns. Note that although FIG. 17 shows a cushioning element 1701 with solid walls 1703 and 1704, it is possible to make a cushioning element 1701 that has columns on its outer walls. The cushioning element is disposed within an optional cover 1707. A container 1708 with relatively stiff or rigid walls 1709 and 1710 of approximately the same size and shape as the cushioning element walls 1703 and 1704 is shown. The container 1708 has a bottom or base 1711 on which the cushioning element is expected to rest. The container 1708 walls 1709 and 1710 serve; to restrict the outward movement of the cushioning element 1701 when a cushioned object is placed on it. When soft gel is used as a cushioning medium, the cushioning element 1701 would tend to be displaced by the object being cushioned were the side walls 1709 and 1710 of the container 1711 not provided. In lieu of a container, any type of appropriate restraining means may be used to prevent side displacement of the cushioning element in response to the deforming force of a cushioned object. For example, individual plastic plates could be placed against the side walls 1703 and 1704 of the cushioning element 1701. Chose plates could be held in place with any appropriate holder, such as the cover 1707. As another example, an appropriate strap or girdle could be wrapped around all exterior side walls 1703 and 1704 of the cushioning element 1701. Such a strap or girdle would serve to restrain the cushioning element 1701 against radial outward displacement in response to a cushioned object resting on the cushioning element.

FIG. 18 depicts an alternative embodiment of a cushion 1801 that includes a cushioning element 1802 and a cover 1803. The cushioning element 1802 has side walls 1808 and 1809 about its periphery, the side walls 1808 and 1809 in this embodiment being generally parallel with the longitudinal axis 1810 of a hollow column 1811 of the cushioning element 1802. A gap 1806 exists between the cover 1803 and the side wall 1809 of the cushioning element. This gap 1806 accommodates the insertion of a stiff or rigid reinforcing side wall support 1804 which may be made of a suitable material such as plastic, wood, metal or composite material such as resin and a reinforcing fiber. Similarly, gap 1807 between side wall 1808 and the cover 1803 may have side wall support 1805 inserted into it. The side wall supports are configured to restrict the cushioning element from being substantially displaced in an outward or radial direction (a direction orthogonal to the longitudinal axis of one of the columns of the cushioning element) so that the cushioning element's columns will buckle to accommodate the shape of a cushioned object, rather than permitting the cushioning element to squirm out from under the cushioned object.

FIG. 19 depicts an alternative embodiment of a cushioning element 1901 including square columns 1908. The cushioning element has outer side walls 1902 and 1903 about its periphery. The reader should note that although the outer periphery of the cushioning element in FIG. 19 is depicted as rectangular, the outer periphery could be of any desired configuration, such as triangular, square, pentagonal, hexagonal, heptagonal, octagonal, any n-sided polygon shape, round, oval, elliptical, heart-shaped, kidney-shaped, quarter moon shaped, n-sided polygonal where n is an integer, or of any other desired shape. The side walls 1902 and 1903 of the cushioning element 1901 have a peripheral strap or girdle 1904 about them. The girdle 1904 has reinforcing side walls 1905 and 1906 which reinforce the structural stability of side walls 1902 and 1903 respectively of the cushioning element 1901. The embodiment of the girdle 1904 depicted in FIG. 19 has a fastening mechanism 1907 so that it may be fastened about the periphery of the cushioning element 1901 much as a person puts on a belt. The girdle 1904 serves to confine the cushioning element 1901 so that when a cushioned object is placed on the cushioning element 1901, the cushioning element will not tend to squirm out from beneath the girdle 1904. Thus, the cushioning element 1901 will tend to yield and conform to the cushioned object as needed by having; its cushioning medium compress and its columns buckle. FIG. 20 depicts an alternative embodiment of a cushioning element 2001. The cushioning element 2001 includes cushioning medium 2002 such as gel formed into column walls 2003 and 2004 to form a column 2005. The column 2005 depicted has a sealed column top 2006 and a sealed column bottom 2007 in order to contain a column filler 2008. The column filler 2008 could be open or closed cell foam, any known fluid cushioning medium such as lubricated spherical objects, or any other desired column filler. The cushioning element 2001 depicted has an advantage of greater firmness compared to similar cushioning elements which either omit the sealed column top and column bottom or which omit the column filler.

FIG. 21 depicts an alternative embodiment of a cushioning element 2101. The cushioning; element 2101 has cushioning medium 2102 formed into column walls 2103 and 2104. The column walls 2103 and 2104 form a column interior 2105. The column 25 2106 has an open column top 2107 and a closed column bottom 2108. In the embodiment depicted, the column 2107 has a firmness protrusion 2109 protruding into the column interior 2105 from the column bottom 2108. The firmness protrusion 2109 depicted is wedge or cone shaped, but a firmness protrusion could be of an desired shape, such as cylindrical, square, or otherwise in cross section along its longitudinal axis. The purpose of the firmness protrusion 2109 is to provide additional support within a buckled column for the portion of a cushioned object that is causing the buckling. When a column of this embodiment buckles, the cushioning element will readily yield until the cushioned object begins to compress the firmness protrusion. At that point, further movement of the cushioned object into the cushion is slowed, as the cushioning medium of the firmness support needs to be compressed or the firmness support itself needs to be caused to buckle in order to achieve further movement of the cushioned object into the cushioning medium.

Referring now to FIG. 22, in another embodiment of the cushion, multiple individual cushioning elements 2201a, 2201b, 2201c, etc. are provided within a single cushion 2200. In such embodiments, the cushions are positioned side-to-side, with or without other materials between the individual cushions, and with or without connecting the individual cushions to one another. For example, sixty-four cushions, each having a thickness of four inches, and four sides each two inches in length, can be placed in an eight-by-eight arrangement to form a four inch thick square cushion having sixteen inch sides. Such cushions may be useful where different cushioning characteristics are desired on different portions of a cushion. Different cushioning characteristics are achieved through varying the materials and/or configurations of the individual cushions.

With reference to FIGS. 23a, 23b, 23c and 23d, another embodiment of a cushion 2301 is shown. Embodiment 2301 includes a first cushioning medium 2302 which forms a cover and a second cushioning medium 2303 which fills the cover. First cushioning medium 2302 may be elastomeric gel material, which is disclosed in detail below. Second cushioning medium 2303 may be the visco-elastomeric material that is disclosed in detail below.

Embodiment 2301 also includes columns 2304, column walls 2305 and an outer periphery 2306. Columns 2304 are formed through cover 2302 and lined with cushioning medium 2302. With reference to FIGS. 23a and 23b, where two adjacent columns 2304a and 2304b are separated only by a thin column wall 2305a (e.g., a column wall having a thickness of only about 0.1 inch or less), the column wall may be made from cushioning medium 2302. Where two adjacent columns 2304c and 2304d are separated by a thicker column wall 2305c, the column wall may include a cover 2302 of the first cushioning medium and is filled with second cushioning medium 2303.

The use of multiple cushioning media in cushion 2301 facilitates tailoring of the rebound, pressure absorption, and flow characteristics of the cushion. Compressibility of cushion 2301 also depends upon the amount of spacing between columns and the formulations of the first second cushioning media 2302 and 2303, respectively.

FIGS. 24a and 24b illustrate another embodiment of the cushioning element 2401. Referring to FIG. 24b, embodiment 2401 includes a cushioning medium 2402, a coating 2403 adhered to the cushioning medium, columns 2404, column walls 2405 that separate the columns, and an outer periphery 2406. Cushioning medium 2402 of embodiment 2401 may be tacky, which facilitates adhesion of coating 2403 thereto. An example cushioning medium 2402 for use in embodiment 2401 is disclosed in detail below. Coating 2403 may be a particulate material, including without limitation lint, short fabric threads, talc, ground cork, microspheres, and others. However, coating 2403 may me made from any material that will form a thin, pliable layer over cushioning medium 2402, including but not limited to fabrics, stretchable fabrics, long fibers, papers, films, and others.

FIGS. 25a, 25b, 25c, 25d, 25e and 25f show another embodiment of a cushioning element 2501. Embodiment 2501 includes cushioning medium 2502, a first set of columns 2503 which are oriented along a first axis x, a second set of columns 2504 which are oriented along a second axis y, a third set of columns 2505 which are oriented along a third axis z, column walls 2506 located between the columns, and an outer periphery 2507. As an example, axis x is perpendicular to both axis y and axis z and axis y is perpendicular to axis z. Columns 2503 and 2504, 2503 and 2505, and/or 2504 and 2505 may intersect each other. FIGS. 25a, 25b and 25c illustrate a cushion 2501 a wherein columns 2503a intersect columns 2504 and columns 2503b intersect columns 2505. FIGS. 25d, 25e and 25f depict a cushion 2501b wherein each of columns 2503 intersect both columns 2504 and columns 2505. Alternatively, none of the columns may intersect any other columns. Other variations of intersection and/or non-intersecting columns are also within the scope.

The spacing and pattern with which each set of columns is positioned determines the total volume of cushioning medium 2502 within the volume of space occupied by the cushioning element 2501. As the volume of cushioning medium 2502 within the volume of space occupied by the cushioning element 2501 decreases, the cushion becomes lighter and easier to compress. Thus, the spacing and pattern of each set of columns may be varied to provide a cushion of desired weight and compressibility. Cushioning elements which have only two sets of columns or more than three sets of columns are also within the scope of embodiment 2501.

With reference to FIG. 26, another embodiment of cushioning element 2601 is shown which includes a first set of columns 2603 which are oriented along a first axis x, a second set of columns 2604 which are oriented along a second axis y, and a third set of columns 2605 which are oriented along a third axis z. As can be seen in FIG. 26, columns 2603, 2604 and 2605 may be thin. Column walls 2606, which are made from a cushioning medium 2602, surround each of the columns. The cushion 2601 shape is defined in part by an outer periphery 2607. As an example, axis x is perpendicular to both axis y and axis z and axis y is perpendicular to axis z. Similar to the cushion of embodiment 2501, columns 2603, 2604 and 2605 may or may not intersect any other columns. Likewise, the spacing between adjacent columns and the arrangement of each of the columns determine the total volume of cushioning medium 2602 within the volume of space occupied by the cushioning element 2601. As the volume of cushioning medium 2602 within the volume of space occupied by the cushioning element 2601 decreases, the cushion becomes lighter and easier to compress. Thus, the spacing and arrangement of columns may be varied to provide a cushion of desired weight and compressibility. Cushions with only two sets of columns or more than three sets of columns are also within the scope of embodiment 2601.

Referring now to FIGS. 27a, 27b and 27c, another embodiment of a cushioning element 2701 is shown. Embodiment 2701 includes cushioning medium 2702, a first set of columns 2703 which are oriented along a first axis x, a second set of columns 2704 which are oriented along a second axis y, a third set of columns 2705 which are oriented along a third axis z, column walls 2706 located between the columns, cavities 2707 formed within the column walls and an outer periphery 2708. As an example, axis x is perpendicular to both axis y and axis z and axis y is perpendicular to axis z. Columns 2703 and 2704, 2703 and 2705, and/or 2704 and 2705 may intersect each other, as in embodiments 2501 and 2601. Alternatively, none of the columns may intersect any other column. The spacing and pattern with which each set of columns is positioned and the number of cavities 2706 formed within the column walls 2707 determine the total volume of cushioning medium 2702 within the volume of space occupied by the cushioning element 2701. As the volume of cushioning medium 2702 within the volume of space occupied by the cushioning element 2701 decreases, the cushion becomes lighter and easier to compress. Thus, the spacing and pattern of each set of columns may be varied to provide a cushion of desired weight and compressibility. Similarly, the size and spacing of the cavities 2706 within the column walls 2707 may also be varied to provide a cushion of desired weight and compressibility. Cushioning elements which have only two sets of columns are also within the scope of embodiment 2701.

FIG. 28 illustrates yet another embodiment of a cushioning element 2801, which has a contoured upper surface. The cushion 2801 shown in FIG. 28 has columns 2803 and 2804 of different heights and column walls 2805 and 2806 of different heights. However, a contoured cushion according to embodiment 2801 could include columns and column walls having any number of different heights. Embodiment 2801 also includes cushioning medium 2802 and an outer periphery 2807. The variability of column and column wall height in embodiment 2801 imparts the cushion with areas having different compressibility and firmness characteristics.

As seen in FIG. 28, cushion 2801 has two distinct levels of columns. The adjacent longer columns 2803 are grouped together, referred to as a set of isolated columns 2808. The shorter columns 2804, which are located between sets 2808, tie cushion 2801 together and form a cushion base 2809.

As an example of the use of cushion 2801, a cushioned object which comes into contact with the top surface thereof will first compress columns 2803, causing the column walls 2805 to buckle. The free area between isolated column sets 2808 enhances the bucklability of columns 2803. In other words, columns 2803 buckle more easily than would columns of the same size, separated by column walls of the same thickness and made from the same material in a cushion having columns of only one general height. If the load of the cushioned object causes complete buckling of columns 2803, columns 2804, which have a greater resistance to buckling than the long columns, provide a secondary cushioning effect, which is more like that of a cushion with columns of one general length.

Referring now to FIG. 29, a cushion 2901 is shown which includes a cushioning medium 2902, columns 2903, column walls 2904, and an outer periphery 2905. Cushioning medium includes a plurality of cells 2906×, 2906b, 2906c, etc. which are filled with gas or another cushioning medium. The cushion 2901 depicted in FIG. 29 has open cells 2906. Alternatively, cushion 2901 may have only closed cells or a combination of open and closed cells. Cells 2906x, 2906b, 2906c, etc. may be of any size and may be dispersed throughout cushioning medium at any density or concentration that will provide the desired cushioning and weight characteristics.

Referring now to FIGS. 30a and 30b, alternative embodiments of the cushions 3001 and 3001 which have light weight column walls 3004 and 3004′, respectively, are shown. Cushions 3001 and 3001′ also include a cushioning medium 3002 and 3002′, columns 3003 and 3003′ and an outer periphery 3005 and 3005′, respectively. Column walls 3004 and 3004′ each include a matrix 3006 and 3006′, respectively, within which are located several voids 3007x, 3007b, 3007c, etc. and 3007×′, 3007b′, 3007c′, etc. and 3008a, 3008b, etc., respectively. Matrix 3006 is made from cushioning medium 3002, 3002′. Voids 3007, 3007′, 3008 are hollow areas formed within matrix 3006 which lighten column walls 3004, 3004′. As example, voids 3007, 3007′ are filled with gas or any other substance which has a density (i.e., specific gravity) less than that of cushioning medium 3002, 3002′. As an example, voids 3007, 3007′ are open celled (i.e., continuous with the outer surface of cushion 3001, 3001′ and exposed to the atmosphere).

FIG. 30a shows cushion 3001, the column walls 3004 of which include a matrix 3006 which forms voids 3007×, 3007b, 3007c, etc. having a multi-sided irregular shape. Column walls which have matrices and pits of other configurations are also within the scope of the cushioning elements. Embodiment 3001 may be formed by removal or destruction of volume occupying objects which are dispersed throughout the cushioning medium as cushion 3001 is formed.

FIG. 30b shows cushion 3001 having a matrix 3006 formed from randomly oriented short tubes 3009a, 3009b, 3009c, etc. which forms voids 3007 and 3008. Voids 3007a, 3007b′, 3007c′, etc. are formed within short tubes 3009a, 3009b, 3009c, etc. and are generally cylindrical in shape. Matrix 3006′ also includes irregularly shaped secondary voids 3008a, 3008b, 3008c, etc. which are formed by the exterior surfaces of tubes 3009 between adjacent tubes.

It is contemplated that the hollow portion of the column will typically be of uniform cross section throughout its length, but this is not necessary for all embodiments. For example, in a column having a circular cross section orthogonal to its longitudinal axis, the diameter of the circle could increase along its length, and adjacent columns could correspondingly decrease along their length (i.e. the columns would be formed as opposing cones). As another example, the column walls could all thicken from one cushion surface to another to facilitate the use of tapered cores (which create the hollow portion of the columns) in the manufacturing tool, which tapering facilitates the removal of the cores from the gel.

As an example the columns of the cushioning element be open at their top and bottom. However, the columns can be bonded to or integral with a face sheet on the top or bottom or both, over all or a portion of the cushion. Or the columns can be interrupted by a sheet of gel or other material at their midsection which is like a face sheet except that it cuts through the interior of a cushioning element.

In an example embodiment of the cushioning element the column walls are not perforated. However, perforated walls and/or face sheets are within the scope hereof. The perforation size and density can be varied by design to control column stiffness, buckling resistance, and weight, as well as to enhance air circulation.

Wall thickness of the columns can be approximately equal throughout the cushioning, element for uniformity, but in special applications of the cushion, wall thickness may be varied to facilitate manufacturing or to account for differing expected weight loads across the cushion or for other reasons.

Typical cushions in the art are ordinarily one piece, but the cushion can be constricted from more than one discontinuous cushioning element. For example, three one-inch thick cushions hereof can be stacked to make a three-inch thick cushion hereof, with or without other materials between the layers, and with or without connecting the three layers to one another.

The cushioning element hereof can be used alone or with a cover. A cover can be desirable when used to cushion a human body to mask the small pressure peaks at the edges of the column walls. This is not necessary if the gel used is soft enough to eliminate these effects, but may be desirable if firmer gels are used. Covers can also be desirable to keep the gel (which can tend to be sticky) clean. If used, a cover should be pliable or stretchable so as not to overly reduce the gross cushioning effects of the columns compressing and/or buckling. A cover would also permit air to pass through it to facilitate air circulation under the cushioned object.

While it is envisioned that the immediate application of the cushion is to cushion human beings (e.g;., seat cushions, mattresses, wheelchairs cushions, stadium seats, operating table pads, etc.), Applicant also anticipates that other objects, including without limitation, animals (e.g. between a saddle and a horse), manufactured products (e.g., padding between a manufactured product and a shipping container), and other objects may also be efficiently cushioned.

As an example, the columns in the cushion are oriented with their longitudinal axis generally parallel to the direction of gravity so that they will buckle under load from a cushioned object rather than collapse from side pressure. Some type of wall or reinforcement may be provided about the periphery of the cushioning element in order to add stability to the cushioning element and in order to ensure that the buckling occurs in order to decrease column length under a cushioned object.

The cushioning element may be described as a gelatinous elastomeric or gelatinous visco-elastomeric material (i.e. gel) configured as laterally connected hollow vertical columns which elastically sustain a load up to a limit, and then buckle beyond that limit. This produces localized buckling in a cushioning element beneath a cushioned object depending upon the force placed upon the cushioning element in a particular location. As a result, protruding portions of the cushioned object can protrude into the cushion without being subjected to pressure peaks. As a result, the cushioning element distributes its supportive pressure evenly across the contact area of the cushioned object. This also maximizes the percentage of the surface area of the cushioned object that is in contact with the cushion.

Each individual column wall can buckle, markedly reducing the load carried by that column and causing each column to be able to conform to protuberances of the cushioned object. Buckling may be described as the localized crumpling of a portion of a column, or the change in primary loading of a portion of a column from compression to bending. In designing structural columns, such as concrete or steel columns for buildings or bridges, the designer seeks to avoid buckling because once a column has buckled, it curves. Far less load than when not buckled. In the columns of this cushion, however, buckling works to advantage in accomplishing the objects. The most protruding parts of the cushioned object cause the load on the columns beneath those protruding parts to have a higher than average load as the object initially sinks into the cushion. This higher load causes the column walls immediately beneath the protruding portion of the cushioned object to buckle, which markedly reduces the load on the protruding portion. The surrounding columns, which have not exceeded the buckling threshold, take up the load which is no longer carried by the column(s) beneath the most protruding portion of the cushioned object.

As an example of the desirability of the buckling provided by the cushioning element, consider the dynamics of a seat cushion. The area of a seated person which experiences the highest level of discomfort when seated without a cushion (such as on a wooden bench) or on a foam cushion is the tissue that is compressed beneath the most protruding bones (typically the ischial tuberosities). When the cushioning element is employed, the area beneath the protruding portions will have columns that buckle, but the remainder of the cushioning element should have columns (which are beneath the broad, fleshy non-bony portion of the person's posterior) which will withstand the load placed on them and not buckle. Since the broad fleshy area over which the pressure is substantially equal is approximately 95% of the portion of the person subjected to sitting pressure, and the area beneath the ischial tuberosity is subjected to less than average pressure due to the locally buckled gel columns (in approximately 5% of that area), the person is well supported and the cushion is very comfortable to sit on.

As another example, the cushioning element is useful in a bed mattress. The shoulders and hips of a person lying on his/her side would buckle the columns in the cushioning element beneath them, allowing the load to be picked up in the less protruding areas of the person's body such as the legs and abdomen. A major problem in prior art mattress cushions is that the shoulders and hips experience too much pressure and the back is unsupported because the abdomen receives too little pressure. The cushion hereof offers a solution to this problem by tending, to equalize the pressure load through local buckling under protruding body parts.

The square columns of FIG. 7 or 8 in the cushion are believed by Applicant to have the best balance between lateral stability (resistance to collapse from side loads) and light weight (which also corresponds to good air circulation and low thermal transfer). Some other types of columns, such those depicted in the other figures or mentioned elsewhere herein, have more cushioning media (typically gel) per cubic inch of cushion for a given level of cushioning support. Thus, the resulting cushions are heavier and have a higher rate of thermal transfer. They are also more costly to manufacture due to the increased amount of cushioning media required. However, columns with oval, circular or triangular cross sections can be used for some cushioning applications because they have a greater degree of lateral stability than square or honeycomb columns since triangles form a braced structure and circles and ovals form structurally sound arches when considered from a lateral perspective. Honeycomb columns such as those shown in FIGS. 2, 4, 5, 7, 8, 9 and 10 generally have the least gel per cubic inch of cushion for a given level of support, but have little lateral stability.

The cushions hereof differ from prior art gel cushions in that, while prior art gel cushions come in a variety of shapes, many are essentially a solid mass. When a cushioned object attempts to sink into a prior art gel cushion, the cushion either will not allow the sinking in because the non-contact portions of the cushion are constrained from expanding, or the cushion expands undesirably by pushing gel away from the most protruding parts of the cushioned object in a manner which tends to increase the reactive force exerted by the gel against areas of the cushioned object which surround the protrusions. In the cushion hereof, the gel has enough hollow space to allow sinking in without expanding the borders of the cushion, so the problem is alleviated.

Another problem with many prior art gel cushions is their weight. For example, a wheelchair cushion made of prior art gel with dimensions of 18″×16″×3.5″ would weigh 35-40 pounds, which is unacceptable to many wheelchair users. A cushion having the same dimensions would weigh approximately seven pounds or less. To be an acceptable weight for wheelchairs, a typical prior art wheelchair gel cushion is made only 1″ thick. To prevent bottoming out through such a thin cushion, the makers increase the rigidity of the gel, which decreases the gel's semi-hydrostatic characteristics, ruining the gel's ability to equalize pressure. Thus, many thin gel cushions relieve pressure no better than a foam cushion. The cushion can be a full 3.5 inches thick needed to allow sinking in for a human user which is in turn needed to equalize pressure and increase the surface area under pressure, while still being light weight.

The cushions hereof differ from prior art honeycomb cushions in part in that gel is used instead of thermoplastic film or thermoplastic elastomer film. Also, a comparatively thick gel is used for the walls of the columns, as compared to very thin films made of comparatively much more rigid thermoplastic film or thermoplastic elastomer film. If thick walls were used in prior art honeycomb cushions, the rigidity of available thermoplastics and available thermoplastic elastomers would cause the cushion to be far too stiff for typical applications. Also, the use of comparatively hard, thin walls puts the cushioned object at increased risk. When the load on a prior art honeycomb cushion exceeds the load carrying capability of virtually all of the columns (i.e., they all buckle), the cushioned object bottoms out onto a relatively hard, rigid, thin pile of thermoplastic film layers. In that condition, the cushioned object is subjected to pressures similar to the pressures it would experience with no cushion at all. The cushioned object is thus at risk of damaging pressures on its most protruding portions.

In comparison, if the same bottoming out occurs on the cushion hereof, the most protruding portions of the cushioned object would be pressed into a pile of relatively thick, soft gel layers, which would add up to typically 20% of the original thickness of the cushion. Thus, the risk of bottoming, out is substantially lowered.

Another difference between prior art thermoplastic honeycomb cushions and the cushion hereof is that the configuration of the cushion is not limited to honeycomb columns, but can take advantage of the varying properties offered by columns of virtually any cross sectional shape. The prior art thermoplastic honeycomb cushions are so laterally unstable that at least one face sheet must be bonded across the open cells. This restricts the air circulation, which is only somewhat restored if small perforations are made in the face sheet or cells. While face sheets and perforations are an option on the cushions hereof, the alternative cross sectional shapes of the columns (e.g., squares or triangles) make face sheets unnecessary due to increased lateral stability and thus perforations are unnecessary since both ends of the configuration of the column can be open to the atmosphere.

The maximum thickness of the walls of the columns of the cushion hereof should be such that the bulk density of the cushion is less than 50% of the bulk density if the cushion were completely solid gel. Thus, at least 50% of the volume of space occupied by the cushioning element is occupied by a gas such as air and the remainder is occupied by gel. The minimum thickness of the walls of the columns is controlled by three factors: (1) manufacturability; (2) the amount of gel needed for protection of the cushioned object in the event of all columns buckling; and (3) the ability to support the cushioned object without buckling the majority of the columns. The thickness would be such that the columns under the most protruding parts of the cushioned object are buckled, and the remaining columns are compressed in proportion to the degree of protrusion of the cushioned object immediately above them but are not buckled.

Cushion Materials

The cushioning media used to manufacture the cushioning element can soft gel. This; assures that the cushion will yield under a cushioned object by having buckling columns and by the cushioning medium itself compressing under the weight of the cushioned object. The soft gel will provide additional cushioning and will accommodate uneven surfaces of the cushioned object. Nevertheless, firmer gels are also useful in the cushioning element, provided that the gel is soft enough to provide acceptable cushioning for the object in the event that all of the columns buckle. Since, with a given type of gel, there is typically a correlation between softness and Young's modulus (stiffness) (i.e., a softer gel is less stiff), and since there is a correlation between Young's modulus and the load carrying capability of a column before buckling, there is typically a need for firmer gels in cushions which will carry a higher load. However, there are other alternatives for increasing a cushion's load carrying capability, such as increasing the column wall thickness, so that the softness of the gel can be selected for its cushioning characteristics and not solely for its load bearing characteristics, particularly in cases where cushion weight is not a factor. Any gelatinous elastomer or gelatinous visco-elastomer with a hardness on the Shore A scale of less than about 15 is useful in the cushioning element. The cushioning medium can have a Shore A hardness of about 3 or less. Or materials which have a hardness of less than about 800 gram bloom can be used. Such materials are too soft to measure on the Shore A scale. Gram Bloom is defined as the gram weight required to depress a gel a distance of four millimeters (4 mm) with a piston having a cross-sectional area of one square centimeter (1 cm) at a temperature of about 23° C. The example gel may be cohesive at the normal useable temperatures of a cushioning element. The example gel will not escape from the cushioning element if the cushioning element is punctured. The example gel has shape memory so that it tends to return to its original shape after deformation.

The cushioning media or gel should also be strong enough to withstand the loads and deformations that are ordinarily expected during the use of a cushion. For a given type of gel, there is typically a correlation between softness and strength (i.e., softer gels are not as strong as harder gels).

Because of their high strength even in soft formulations, their low cost, their ease of manufacture, the variety of manufacturing methods which can be used, and the wide range of Young's modulus which can be formulated while maintaining the hydrostatic characteristics of a gel, the gel formulations which follow are example gels to be used in cushions.

Applicant believes that the reader might benefit from a general background discussion of the chemistry underlying the gels prior to reading about the example formulations.

Chemistry of Plasticizer-Extended Elastomers

A basic discussion of the chemical principles underlying the characteristics and performance of plasticizer-extended elastomers is provided below to orient the reader for the later discussion of the particular chemical aspects of the material for use in the cushions.

The example gel cushioning medium is a composition primarily of triblock copolymers and plasticizers, both of which are commonly referred to as hydrocarbons. Hydrocarbons are elements which are made up mainly of Carbon (C) and Hydrogen (H) atoms. Examples of hydrocarbons include gasoline, oil, plastic and other petroleum derivatives.

Referring to FIG. 31a, it can be seen that a carbon atom 3110 typically has four covalent bonding sites “•”. FIG. 31b shows a hydrogen atom 3112, which has only one covalent bonding site •. With reference to FIG. 31c, which represents a four-carbon molecule called butane, a “covalent” bond, represented at 3116 as “-”, is basically a very strong attraction between adjacent atoms. More specifically, a covalent bond is the linkage of two atoms by the sharing of two electrons, one contributed by each of the atoms. For example, the first carbon atom 3118 of a butane molecule 3114 shares an electron with each of three hydrogen atoms 3120, 3122 and 3124, represented as covalent bonds 3121, 3123 and 3125, respectively, accounting for three of carbon atom 3118's available electrons. The final electron is shared with the second carbon atom 3126, forming covalent bond 3127. When atoms are covalently bound to one another, the atom-to-atom covalent bond combination makes up a molecule such as butane 3114. An understanding of hydrocarbons, the atoms that make hydrocarbons and the bonds that connect those atoms is important because it provides a basis for understanding the structure and interaction of each of the components of the example gel material.

As mentioned above, the example gel cushioning material utilizes triblock copolymers. With reference to FIGS. 32a and 32b, a triblock copolymer is shown. Triblock copolymers 3210 are so named because they each have three blocks-two endblocks 3212 and 3214 and a midblock 3216. If it were possible to grasp the ends of a triblock copolymer molecule and stretch them apart, each triblock copolymer would have a string-like appearance (as in FIG. 32a), with an endblock being located at each end and the midblock between the two endblocks.

FIG. 33a depicts the example endblocks of the copolymer most example for use in the example gel material, which are known as monoalkenylarene polymers 3310. Breaking the term “monoalkenylarene” into its component parts is helpful in understanding the structure and function of the endblocks. “Aryl” refers to what is known as an aromatic ring bonded to another hydrocarbon group. Referring now to FIG. 33b, benzene 3312, one type of aromatic ring, is made up of six carbon molecules 3314, 3316, 3318, 3320, 3322 and 3324 bound together in a ring-like formation. Due to the ring structure, each of the carbon atoms is bound to two adjacent carbon atoms. This is possible because each carbon atom has four bonding sites. In addition, each carbon atom C of a benzene molecule is bound to only one hydrogen atom H. The remaining bonding site on each carbon atom C is used up in a double covalent bond 3326, 3327, which is referred to as a double bond. Because each carbon atom has only four bonding sites, double bonding in an aromatic ring occurs between a first carbon and only one of the two adjacent carbons. Thus, single bonds 3116 and double bonds 3326 alternate around the benzene molecule 3312. With reference to FIG. 33c, in an aryl group 3328, one of the carbons 3330 is not bound to a hydrogen atom, which frees up a bonding site R for the aryl group to bond to an atom or group other than a hydrogen atom.

Turning now to FIG. 33d, “alkenyl” 3332 refers to a hydrocarbon group made up of only carbon and hydrogen atoms, wherein at least one of the carbon-to-carbon bonds is a double bond 3334 and the hydrocarbon group is connected to another group of atoms R′, where R′ represents the remainder of the hydrocarbon molecule and can include a single hydrogen atom. Specifically, the “en” signifies that a double bond is present between at least one pair of carbons. The “yl” means that the hydrocarbon is attached to another group of atoms. For example, FIG. 33e shows a two carbon group having a double bond between the carbons, which is called etheny13336. Similarly, FIG. 3f illustrates a three carbon group having a double bond between two of the carbons, which is called propenyl 3338. Referring again to FIG. 33a, in a monoalkenylarene such as styrene, a carbon 3340 with a free bonding site of an alkenyl group 3332 is bonded to the aryl group 3328 at carbon atom 3330, which also has a free bonding site. In reference to FIG. 33c, aryl group 3328 is part of a monoalkenylarene molecule when R is an alkenyl group. The “mono” of monoalkenylarene explains that only one alkenyl group is bonded to the aryl group.

The monoalkenylarene end blocks of a triblock copolymer are polymerized. Polymerization is the process whereby monomers are connected in a chain-like fashion to form a polymer. FIG. 34a depicts a polymer 3410, which is basically a large chain-like molecule formed from many repeating smaller molecules, called monomers, M1, M2, M3, etc., that are bonded together. P and P′ represent the ends of the polymer, which are also made up of monomers FIG. 34b illustrates a monoalkenylarene end block polymer 3414, which is a chain of monoalkenylarene molecules 3416a, 3416b, 3416c, etc. The chain of FIG. 34b is spiral, or helical, in shape due to the bonding angles between styrene molecules. P represents an extension of the endblock polymer helix in one direction, while P′ represents an extension of the endblock polymer helix in the opposite direction.

As FIG. 34c shows, monoalkenylarene molecules are attracted to one another by a force that is weaker than covalent bonding. The primary weak attraction between monoalkenylarene molecules is known as hydrophobic attraction. An example of hydrophobic attraction is the attraction of oil droplets to each other when dispersed in water. Therefore, in its natural, relaxed state at room temperature, a monoalkenylarene polymer resembles a mass of entangled string 3414, as depicted in FIG. 34d. The attraction of monoalkenylarene molecules to one another creates a tendency for the endblocks to remain in an entangled state. Similarly, different monoalkenylarene polymers are attracted to each other. The importance of this phenomenon will become apparent later in this discussion.

Like the end blocks of a triblock copolymer, the midblock is also a polymer. The example triblock copolymer for use in the elastomer component of the example cushioning medium includes is an aliphatic hydrocarbon midblock polymer. Traditionally, “aliphatic” meant that a hydrocarbon was “fat like” in its chemical behavior. Referring to FIGS. 35a through 35c, which, for simplicity, do not show the hydrogen atoms, an “aliphatic compound” is now defined as a hydrocarbon compound which reacts like an alkane 3510 (a hydrocarbon molecule having only single bonds between the carbon atoms), an alkene 3512 (a hydrocarbon molecule wherein at least one of the carbon-to-carbon bonds is a double bond) 3514, an alkyne (a hydrocarbon molecule having a triple covalent bond 3515 between at least one pair of carbon atoms), or a derivative of one or a combination of the above.

Referring now to FIG. 35d, which omits the bound hydrogen atoms for simplicity, aliphatic hydrocarbons known as conjugated dienes 3516 are depicted. These are the example midblock monomers used in the triblock copolymers of the example gel material. A “diene” is a hydrocarbon molecule having two (“di”) double bonds (“ene”). “Conjugated” means that the double bonds 3518 and 3520 are separated by only one single carbon-to-carbon bond 3522. In comparison, FIG. 35e shows a hydrocarbon molecule having two double carbon-to-carbon bonds that are separated by two or more single bonds, 3530, 3532, etc., which is referred to as an “isolated diene” 3524. When double bonds are conjugated, they interact with each other, providing greater stability to a hydrocarbon molecule than would the two double bonds of an isolated diene.

FIGS. 36a through 36d illustrate examples of various monomers useful in the midblock of the triblock copolymers example for use in the elastomer component of the example gel cushioning medium, including molecules (monomers) such as ethylene-butylene (EB) 3612, ethylene-propylene (EP) 3614, butadiene (B) 3616 (either hydrogenated or non-hydrogenated) and isoprene (I) 3618 (either hydrogenated or non-hydrogenated). The different structures of these molecules provide them with different physical characteristics, such as differing strengths of covalent bonds between adjacent monomers. The various structures of monomer molecules also provides for different types of interaction between distant monomers on the same chain (e.g., when the midblock chain folds back on itself, distant monomers may be attracted to one another by a force weaker than covalent bonding, such as hydrophobic interaction, hydrophilicinteraction, polar forces or Vander Waals forces).

Referring to FIGS. 36a and 36b, x, y and n each represent an integral number of each bracketed unit: “x” is the number of repeating ethylene (—CH2—CH2—) units, “y” is the number of repeating butylene (in FIG. 36a) or propylene (in FIG. 36b) units, and “n” is the number of repeating poly(ethylene/butylene) units. Numerous configurations are possible. As shown in FIGS. 37a through 37d, the midblock may contain (i) only one type of monomer, EB, EP, B or I or, as FIGS. 37e and 37f illustrate, (ii) a combination of monomer types EB and EP or B and 1, providing for wide variability in the physical characteristics of different midblocks made from different types or combination of types of monomers. The interaction of physical characteristics of each molecule (monomer and block) determines the physical characteristics of the tangible, visible material. In other words, the type or types of monomer molecules which make up the midblock polymer play a role in determining various characteristics of the material of which the midblock is a part.

Attributes such as strength, elongation, elasticity or visco-elasticity, softness, tackiness and plasticizer retention are, in part, determined by the type or types of midblock monomers. For example, referring again to FIG. 37a, the midblock polymer 3216 of a triblock copolymer containing material may be made up primarily or solely of ethylene-butylene monomers EB, which contribute to that material's physical character. With reference to FIG. 37e, in comparison to the material having a midblock made up solely of EB, a similar triblock containing material, wherein the midblock polymer 3216 of the triblocks are made up of a combination of butadiene B and isoprene I monomers, may have greatly increased strength and elongation, similar elasticity or visco-elasticity and softness, reduced tackiness and reduced plasticizer bleed.

The monomer units of the midblock have an affinity for each other. However, the hydrophobic attraction of the midblock monomers for each other is much weaker than the non-covalent attraction of the end block monomers for one another.

Referring now to FIG. 38a, which shows a polystyrene-poly(butadiene+isoprene) polystyrene triblock copolymer, in a complete triblock copolymer 3810, each end 3812 and 3814 of midblock chain 3216 is covalently bound to an end block 3212 and 3214. P and P″ represent the remainder of the endblock polymers 3212 and 3214 respectively. P′ represents the central portion of midblock polymer 3216. Many billions of triblock copolymers combine to form a tangible material. The triblock copolymers are held together by the high affinity (i.e., hydrophobic attraction) that monoalkenylarene molecules have for one another. In other words, as FIG. 38b illustrates, the endblocks of each triblock copolymer molecule, each of which resemble an entangled mass of string 3414, are attracted to the endblocks of another triblock copolymer. When several endblocks are attracted to each other, they form an accretion of endblocks, called a domain or a glassy center 3816. Agglomeration of the endblocks occurs in a random fashion, which results in a three-dimensional network 3818 of triblocks, the midblock 3216 of each connecting endblocks 3212 and 3214 located at two different domains 3816a and 3816b. In addition to holding the material together, the domains of triblock copolymers also provide it with strength and rigidity.

Plasticizers are generally incorporated into a material to increase the workability, pliability and flexibility of that material. Incorporation of plasticizers into a material is known as plasticization. Chemically, plasticizers are hydrocarbon molecules which associate with the material into which they are incorporated, as represented in FIG. 39a. In the example gel material, plasticizer molecules 3910 associate with the triblock copolymer 3210, and increase its workability, softness, elongation and elasticity or visco-elasticity. Depending upon the type of plasticizer used, the plasticizer molecules associate with either the endblocks, the midblock, or both. In order to preserve the strength of the example gel materials, Applicant prefers the predominant use of plasticizers 3910 which associate primarily with midblock polymer 3216 of triblock copolymer 3818, rather than with the end blocks. However, plasticizers which associate with the end blocks may also be useful in some formulations of the example gel material. Plasticizers are also desired which associate with the principle thermoplastic polymer component of the gel material.

Chemists have proposed four general theories to explain the effects that plasticizers have on certain materials. These theories are known as the lubricity theory, the gel theory, the mechanistic theory and the free volume theory.

The lubricity theory, illustrated in FIGS. 39b through 39d, assumes that the rigidity of a material (i.e., its resistance to deformation) is caused by intermolecular friction. Under this theory, plasticizer molecules 3910 lubricate the large molecules, facilitating movement of the large molecules over each other. See generally, Jacqueline 1. Kroschwitz, ed., CONCISE ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING 734-44, Plasticizers (1990), which is hereby incorporated by reference. In the case of triblock copolymers, lubrication of the endblocks should be avoided since the endblock domains are responsible for holding the triblock copolymers together and impart the material with strength (e.g., tensile strength during elongation). Thus, a plasticizer which associates with the midblocks is example. According to the lubricity theory, when manipulative force is exerted on the material, plasticizer 3910 facilitates movement of midblocks 3216 past each other. Id. at 734-35. The arrows in FIGS. 39b, 39c and 39d represent the motion of midblocks 3216 with respect to each other. FIG. 39b represents adjacent midblocks being pulled away from each other. FIG. 39c represents two midblocks being forced side-to-side. FIG. 39d represents adjacent midblocks being pulled acros