GB2133980A - Membrane covered cushion having indented pattern and method for making same - Google Patents

Abstract

A cushion e.g. for a vehicle seat comprises a resilient compressible deformable body (40), such as a polyurethane foam block, which has an indented design (44) formed in a surface (46) thereof, and a flexible stretchable membrane (42), either of cloth or plastic, which covers the body surface (46), follows the contours of the indented design (44) and is adhesively secured thereto. The cushion is manufactured by forcing (i) the body (40) which is preformed with the indented design into the flexible stretchable membrane (42) which is heated to about 250 to 300 DEG F and has an adhesive (48) on one side thereof, and (ii) the body and membrane into a fixture having a die cavity generally conforming in size and shape to the body (40) but including projections which correspond in shape to but are of greater height than the design indentations (44) in the body (40). After several minutes, cooling occurs, the membrane takes a set and the adhesive cures to cause good adhesion, and the finished cushion is then removed from the die cavity. <IMAGE>

Description

SPECIFICATION Membrane covered cushion having indented pattern and method for making same Background of the Invention Field of Use This invention relates generally to membrane covered compressible cushions having indented ornamental or functional designs or patterns formed in the top surface thereof.

Description of the Prior Art Seats for vehicles, such as automobiles, motorcycles or construction machines, or for residential or commercial furniture sometimes employ resiliently compressible seat cushions or back-rest cushions which are either removable from or permanently attached to the seat structure in which they are employed. Such cushions frequently comprise a resiliently compressible body, in the form of a block or large piece of foamlike material, such as polyurethane, which is covered by a flexible membrane, such as a sheet of cloth or plastic, which is secured to one or more surfaces of the body by direct bonding, or by an adhesive, or by stitching or stapling along the edges and corners of the membrane.In some cushions the body takes the form of a pre-shaped and pre-sized block of foam-like material which is then covered with the membrane which is then suitably attached to the body. In other cushions, a membrane is placed in a mold of desired size and shape and arranged to follow the shape of the mold, and then an expanded foamable liquid is poured into the mold over the membrane and allowed to expand and set, adhering to the membrane in the process. The membrane used in both fabrication methods explained above may taken the form of a flexible sheet of woven or knitted cloth or plastic, such as vinyl, and may, if desired, be stretchable as well as flexible.

Sometimes it is desirable, either for functional reasons or aesthetic reasons or both, to provide an indented pattern or design in the major exposed surface of the cushion. In cushions using preformed blocks of foam it is necessary to form the pattern indentations in the appropriate surface of the block and to somehow force the appropriate parts of the membrane into these indentations until the adhesive between the block and membrane sets up. In cushions wherein expandable foam is poured into a mold, it is necessary to form the pattern indentations in the mold and to make sure that the membrane closely conforms to the shape of the mold and indentations. Heretofore, both prior art methods of making cushions with indentational designs as described above were not entirely satisfactory and numerous problems arose.

For example, improper adhesion between the block and membrane sometimes occurs in the indentation and "bridging" occurs, thereby resulting in a defective design in the finished cushion. Or, in the case where liquid foam is poured into a mold lined with a cloth membrane, the liquid may bleed through the relatively porous cloth resulting in a defective, unattractive, rejectable finished cushion. In addition, the tendency of the molded body to shrink in its mold as it set, caused it to pull away from the membrane and thus further reduce the likelihood of an ill-formed unsound design.

Summary of the Present Invention In accordance with the present invention there is provided a compressible flexible deformable cushion usable as a seat cushion or back-rest cushion in a vehicle seat or article of furniture and having an indented ornamental or functional design formed in an outer surface thereof.

The cushion comprises a resilient compressible deformable body, such as a polyurethane foam block, which has the indented design formed therein on one surface and which is covered by a flexible stretchable membrane, such as a sheet of cloth or plastics, which follows the contours of the design, and the membrane is bonded or otherwise adhesively secured at least to the said one surface of the body and to the design indentations formed therein.

The cushion is manufactured by providing a preformed molded body having design indentations formed therein; providing a fixture having a cavity conforming to the size and shape of the preformed body but including design projections which are of greater height than the depth of the corresponding design indentations in the body; providing a sheet of flexible stretchable membrane heated to about 2500 to 3000F and having an adhesive on the side thereof away from the fixture and placing it in the fixture cavity; inserting the preformed molded body into the fixture cavity and against the membrane; physically forcing the molded body and underlying membrane into the fixture cavity as by means of a weighted or forcibly pressurized plate to cause the fixture design projections and the membrane portions thereagainst to penetrate deeply into the body at the design indentation therein; allowing cooling to occur whereby the membrane takes a set and the adhesive cures to cause good adhesion between the membrane and the surface of the body containing the design and the design, and removing the cushion from the fixture cavity.

A cushion in accordance with the invention offers several advantages over the prior art. For example, the design or pattern formed therein is well and clearly defined. The membrane adheres completely and positively to the underlying body in the indentations and at the adjacent raised portions and no undesirable bridging occurs. As a result, the finished cushion has a better appearance and is more rugged and lasting in use.

Use of a preformed block instead of in-situ expanded liquid foam at the time the membrane is applied eliminates liquid leakage or bleeding through porous membranes. The equipment and steps required to carry the method in accordance with the invention are relatively few, simple and easy to employ.

Other objects and advantages will hereinafter appear.

Drawings Fig. 1 is a perspective view of the front, top and one side of a vehicle seat employing a seat cushion and back-rest cushion in accordance with the present invention; Fig. 2 is a perspective view of the front, bottom and other side of the seat cushion shown in Fig. 1; Fig. 3 is an enlarged perspective view, partly in cross section, of a portion of the seat cushion of Fig. 2; Fig. 4 is an exploded perspective schematic view of equipment and components employed in making the seat cushion of Figs. 1 through 3; Fig. 5 is an exploded view, partly in cross section, of a portion of certain manufacturing equipment and cushion components shown in Fig. 4 and showing them in pre-assembly disposition;; Fig. 6 is a view similar to Fig. 5 but showing the equipment and components of Fig. 5 being joined in another stage of manufacture; and Fig. 7 is a view similar to Fig. 6 but showing still another stage of manufacture where the components are joined together.

Description of Preferred Embodiments Referring to Fig. 1 , the numeral 10 designates a seat which is usable in a vehicle, such as an automobile, a construction machine, tractor or the like, or which could be used as an article of domestic or commercial furniture. Seat 10 comprises a rigid supporting frame 12, having an appropriate pedestal 14, and on which are mounted a seat cushion 16 and a back-rest cushion 18, each constructed and manufactured in accordance with the present invention. The cushions 16 and 18 may be removable from frame 12 or permanently secured thereto by means not shown. The cushions 16 and 18 may be assumed to be substantially identical in construction and mode of manufacture and, therefore, only seat cushion 16 is hereinafter described in detail.Fig. 2 shows seat cushion 16 (hereinafter simply referred to as "cushion") as removed from seat frame 12 and disposed to display structural details on the underside thereof.

As Figs.1,2 and 3 show, cushion 16 generally comprises an upper, outer or exposed surface 20, a bottom surface 22, a front surface 24, a rear surface 26 and right and left side surface 28 and 30, respectively (with the terms left and right being orientated with respect to a seat occupant, not shown). Upper surface 20 of cushion 1 6 is provided with a design 32, which may be ornamental or functional or both, and which comprises design indentations 34 extending inwardly into surface 20 and relatively raised portions 35 between or adjacent to the indentations 34. The indentations 34 shown in Fig. 1 include, for example, six grooves or indentations such as 36 extending fore and aft and three grooves or indentations such as 38 extending laterally and transversely in intersecting relationship to the grooves 36.More or fewer indentations or other arrangements could be provided.

Figs. 2 and 3 show that cushion 16 comprises the following components, namely, a resilient compressible deformable body 40, such as a polyurethane foam block, which has the design indentations 44 formed therein on the block surface 46 and also has an opposite rear surface 47, which body is covered at least on surface 46 by a flexible stretchable membrane 42, such as a sheet of cloth or plastic, which follows the contours of the design, and the membrane 42 is bonded or otherwise adhesively secured at least to the said one block surface 46 of the body 40 and to the design indentations 44 formed therein as by a film or layer of adhesive material 48. Membrane 42 also preferably adheres to the four sides 52 of body 40 and to portions of bottom 54 of body 40, as Figs. 2 and 3 show.

In an actual embodiment of the invention which was made and tested, body 40 was fabricated of known commercially available constituents in the form of two liquids which, when mixed together, provide a mass of polyurethane foam material which then cures or dries after several minutes into a resilient compressibly deformable nonadhesive body.

Furthermore, actual embodiments were made and tested using membrane 42 in the form of commercially available stretchable vinyl sheets and in the form of sheets of knitted stretchable 100 percent nylon fabrics, such as is available from ADELE KNITS Company of 800 Chatham Road, Winston-Salem, North Carolina 27101, Style No. 438 in 51" widths and is 180 percent stretchable lengthwise and 190 percent stretchable widthwise.

Also, in the actual embodiments made and tested, the adhesive layer 48 employed Type 3824 low viscosity liquid adhesive utilizing a base of synthetic rubber and resin, and a keytone solvent as a vehicle. This adhesive, which is welladapted for use with either of the aforementioned membranes 42, is sprayable, bonds in 3 to 20 minutes depending on application, reaches 90 percent of total bonding strength in 24 hours, and is resistant to moisture, oil, plasticizers and heat. This adhesive is available from St. Clair Rubber Company, 1765 Michigan Avenue, Marysville, Michigan 48040.

The cushion 16 is manufactured in accordance with the following method and in accordance with the following steps, using the aforedescribed cushion components (namely, the preformed molded body 40, a membrane 42, and the adhesive layer 48). As Fig. 4 shows, the method uses the following manufacturing equipment, namely: a fixture 60 for receiving the body 40 and membrane 42; a frame 62 for conveniently supporting the membrane 42 for placement in a heating oven (not shown) and then in the fixture 60; an adhesive applicator-device such as a spray gun 64; a flat rigid platen 66 for application against the rear surface 47 of body 40; and force application means for platen 66, either in the form of a heavy weight 67 (on the order of 50 pounds) embodied in or resting on platen 66 or in the form of a hydraulic ram (not shown) for applying downward force or pressure to platen 66.

The fixture 60 comprises an outer framework 68 in which a rigid die 70, formed of zinc, or aluminum or some suitable metal or alloy or other material, is rigidly mounted. Die 70 defines a cavity 72 which includes a floor 74 from which design projections 76 extend upwardly. The cavity 72 of die 70 is exactly the same size and shape of the finished cushion 16 except that the height of the design projections 76 is greater than (about double) the depth of the corresponding preformed design indentations 44 in body 40 or the design indentations 32 in finished cushion 16.

A means (not shown) is provided with means for heating the membrane 42 to about 2500 to 3000F and such means comprises, for example, a heating oven (not shown), or other types of heating means (not shown) could be employed.

Frame 62 may taken the form of an open rectangular metal, wood or plastic frame having releasable fasteners 84 thereon for releasably securing the membrane 42 thereon.

The adhesive application device comprises the spray gun 64 which operates in a conventional manner to apply adhesive layer 48 in liquid form under pressure in the form of a spray 86 from a source of liquid adhesive such as a pressurized tank 88 to membrane 42 and body 40.

Cushion 16 is manufactured as follows.

Referring to Figs. 4 and 5, the membrane 42 is heated to proper temperature. The heated membrane 42 is then sprayed or otherwise coated with a layer 48 of adhesive #nd placed above fixture 60. The preformed body 40, formed to desired shape and size and having an appropriate design indentation 44 in its surface 46, is then disposed over the coated surface of the membrane 42. Then, as Fig. 6 shows, the body 40 is forced downwardly against the heated, coated membrane 42 and both enter the die cavity 72.

The platen 66 presses downwardly against the rear surface 47 of body 40 under appropriate force and, as this occurs, it causes the design projections 76 to bear against flexible stretchable membrane 42 and the latter penetrates deeply into the design indentations 44 in body 40 and beyond their normal depth. In practice, as Fig. 6 makes clear, a 6-inch thick body 40 was temporarily reduced to about half that thickness.

This disposition of components and application of pressure is maintained for several minutes until good adhesive adhesion is achieved and until the membrane is cooled to a level where the adhesive layer 48 sets and the membrane 42 takes a set.

Thereafter, the platen 66 is removed, the frame 62 is detached from the membrane 42, and the cushion 16 is removed from the die cavity 72. At this point any excess membrane 42 may be trimmed away or, if preferred, caused to adhere to other portions of body 40 as by adhesives, stitching, stapling or the like.

Claims (15)

1. A cushion comprising: a body fabricated of resilient compressible deformable material, said body having a surface and an indented design on said surface; a flexible stretchable membrane overlying said surface and conforming to said indented design; and means for effecting adhesion between said membrane and said surface and said indented design.

2. A cushion according to claim 1 wherein those portions of said membrane which conform to said surface and to said indented design are thermoset.

3. A cushion according to claim 2 wherein said membrane is selected from a class of materials comprising woven, knitted and crocheted sheet material and plastic sheet material.

4. A cushion according to claim 2 or 3 wherein said material of said body comprises foraminous material.

5. A cushion comprising: a body fabricated of resilient compressible deformable material, said body having a plurality of surfaces including a first surface with an indented design thereon and side surfaces intersecting said first surface; a flexible stretchable membrane overlying said first surface and conforming to said indented design and overlying at least some of said side surfaces; and means for effecting adhesion between said membrane and said first surface and said indented design and between said membrane and at least some of said side surfaces.

6. A cushion according to claim 5 wherein said membrane is thermoset.

7. A cushion according to claim 6 wherein said membrane is selected from a class of materials comprising woven, knitted and crocheted sheet material and plastic sheet material.

8. A cushion according to claim 5 or 6 or 7 wherein said body comprises foraminous material.

9. A method of making a cushion having an indented pattern on a side thereof comprising the steps of: providing a resilient compressible body having an indented pattern of predetermined depth formed in a surface of said body; providing a flexible stretchable membrane; applying adhesive material between said body surface and said membrane; providing a fixture having a wall and a projecting pattern on said wall, said projecting pattern conforming to said indented pattern but projecting from said wall for a distance greater than said predetermined depth of said indented pattern; forcing said body against said membrane and the latter against said projecting pattern to effect compression of said body and stretching of said membrane as said projecting pattern forces said membrane deeply into said indented pattern in said body;; allowing said adhesive material to set sufficiently to secure said membrane to said body; and relieving said force.

10. A method according to claim 9 including the further steps of heating said membrane before applying said force and allowing said membrane to cool and take a set before relieving said force.

11. A method of making a cushion having an indented pattern of predetermined depth on a side thereof comprising the steps of: providing a fixture having a cavity therein generally corresponding in shape and size to a portion of said cushion, said cavity having a wall and a projecting pattern extending from said wall, said projecting pattern conforming in configuration to said indented pattern but projecting from said wall for a distance greater than the depth of said indented pattern; providing a resilient compressible body having an indented pattern of a second predetermined depth formed in a surface of said body; providing a flexible stretchable membrane; applying adhesive material between said body surface and said membrane; inserting said membrane and said body in said cavity in said fixture;; forcing said body against said membrane and the latter against said projecting pattern to effect compression of said body and stretching of said membrane as said projecting pattern forces said membrane deeply into said indented pattern in said surface of said body; allowing said adhesive material to set sufficiently to secure said membrane to said body; relieving said force to enable decompression of s#aid body; and removing said cushion from said cavity.

12. A method according to claim 11 including the further steps of heating said membrane before applying said force and allowing said membrane to cool and take a set before relieving said force.

13. A method according to claim 12 wherein said membrane comprises nylon stretch fabric which is heated to about 2500F to 3000 F.

14. A cushion substantially as described and as shown in the accompanying drawings.

15. A method of making a cushion substantially as described with reference to the accompanying drawings.