US 3507727 A
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Description (OCR text may contain errors)
April 21, 1970 Q L. MARSHACK 3,507,727
METHOD OF MAKING AND SEAMIIIG COVERED FOAM CUSHIONING Filed Feb. L. 1966 I N V EN TOR. AQV/A/C; L. MARS/46K ATTORNEK United States Patent METHOD OF MAKING AND SEAMING COVERED FOAM CUSHIONING Irving L. Marshack, La Jolla, Calif., assignor, by mesne assignments, to Mobay Chemical Company, Pittsburgh,
Pa., acorporation of Delaware Filed Feb. 1, 1966, Ser. No. 524,251 Int. Cl. B32b 31/00 US. Cl. 156-153 6 Claims ABSTRACT OF THE DISCLOSURE A contoured seamed structure and method for preparing the same by beveling the edges of a block of foam, placing the beveled block within a confining member having substantially the same length and width dimensions but a depth less than that of the block after lining the confining member with a flanged covering material, covering the block disposed in the confining member On both sides with sheets of covering material, compressing the block to the depth of the confining member between two surfaces, sealing the covering sheets to the flanges of the lining of the confining member, releasing the pressure and removing from the confining member the contoured seamed structure having a core maintained under a transverse compression via the seal between the sheets of the covering material and the lining of the confining member which extends around the side of the structure and which is spaced from the top and bottom surfaces thereof.
This invention relates to a unique seamed structure and to a method for fabricating the same.
Generally, in the fabrication of cushions and similar types of structures for use in furniture such as couches and easy chairs as well as in the fabrication of cushions to be used just as throw pillows or TV cushions, the de sired configuration is achieved and the covering material is secured in place by means of a pair of seams around the outer edges at the top and bottom of the structure. The seams are generally the result of a stitched jointure of the top and bottom covering sheets with the side covering sheet or sheets around the filler material, and serve the dual purpose of enabling the cushion to retain its shape while keeping the filler confined therein. In the production of such things as cushions and mattresses, it has been both economically and expedentially necessary to situate these seams around the top and bottom perimeter of the structure thus resulting in an essentially squared-01f type of product having a hard and uncomfortable piping around its edges. As a consequence, the structure cannot be contoured comfortably nor can it be used without some discomfort as a seating or lounging cushion. Where attempts have been made to obviate this hard, uncomfortable seam edge, it has been found that either the cost of production is prohibitive because there I is no expedient way to do it or else an entirely unsatisfactory type of cushion results.
In the latter instance, some attempts have been made to prepare a cushion or similar type of structure having rounded-off edges with the seam at the center of the depth of the structure. Such processes require that a block of foam be compressed to a very small depth while the perimeter, or alternatively, the whole surface area, is heated to insure that a seam is obtained at the side of the structure. Thus, in the preparation of a contoured structure to be sold to the consumer, the covering material is sealed to the cushion at the same seam area and in the same sealing operation as already described. Assuming the use of a vinyl covering material, the seam is made up of a layer of vinyl at the top and bottom of the seam 3,507,727 Patented Apr. 21, 1970 with the foam material intruding therebetween. It has been found, however, that at any point at which the foam intrudes between the vinyl layers the weld or seam is a failure and an entirely unsatisfactory product results.
It is therefore an object of this invention to provide a seamed structure which is devoid of the foregoing disadvantages.
It is a further object of this invention to provide a method for the production of contoured structures which do not have a hard, piped seam around their top and bottom perimeters.
Still another object of this invention is to provide a process for the production of a contoured structure which does not have a stitched seam and which has rounded-off edges.
Yet another object of this invention is to provide a process for the production of seamed structures having strong and durable seams located at the side of the structure.
Other objects will become apparent from the following description taken in conjunction with the accompanying drawings throughout which like reference characters indicate like parts, and in which FIGURE I is a view of a rectangular block of foam having its edges beveled.
FIGURE II is a side elevation of the beveled foam block in a box ring die with the covering material in place before the foam is compressed and the covering materials are welded together.
FIGURE III is a side elevation of a completed crowned cushion.
According to this invention, the foregoing objects and others are achieved by a process which comprises beveling the edges of a block of foam, disposing it within a confining member lined with a flanged covering material, the length and width dimensions of the confining member being substantially the same as those of the foam but the depth dimension being less than that of the foam, covering the foam block top and bottom with a covering material, compressing the block of foam to the depth of the confining member, fusing the top and bottom sheets to the lining of the confining member to form a seam, releasing the pressure and removing the block from the confining member to yield a contoured seamed structure.
The process of this invention allows for a unique method of sealing a foam core having beveled edges within a suitable covering material while the foam is compressed, preferably using an electronically energized sealing agency, to prepare a cushion or some similar article. A structure is prepared which has a side thickness or depth of a smaller dimension than that of the center of the core, thereby giving a crowned edge to the structure. Even more significant than all of the foregoing, however, the process of this invention permits the fabrication of a cushion or similar structure from a block of compressed foam wherein the seams formed are perfect every time because they do not have any foam incorporated in them in spite of the compression of the foam. Therefore, a comfortable and aesthetically pleasing product as well as an extraordinarily sturdy one is produced. The process of this invention also permits the fabrication of seamed structures to be completed with the sealing operation since the electronically energized agency which produces the seam or weld can also cause a tear line to be formed along the outer edge of the seam. The excess covering material can thus be easily removed to yield a finished product without the necessity for a separate cutting or trimming step.
As far as the consumer is concerned, the product of the process of this invention is far more desirable than similar conventional products which can be manufactured in the prior art fashion. For example, in the production of cushions for sofas and easy chairs as well as for throw pillows and TV cushions, conventional techniques yield a product having a hard and uncomfortable piping around their perimeter which hits the sensitive back of the knee area when one sits on them. Further, when used as throw pillows or TV cushions it is unavoidable that the hard seamed edges around the top and bottom of the cushions will come into contact with the user at some portion of his anatomy thus causing discomfort. This is also a consideration in the production of mattresses and mats as well as pads and similar types of structures covered with a thermoplastic material. Furthermore, the seams which are stitched around the top and bottom perimeters of a cushion by conventional techniques readily catch dirt and grit which attack and abraid the structure at its weakest point-the seam. Consequently, great expense has been undertaken to construct these seams in such a manner that the seam traps as little grit as possible. Notwithstanding, the problem has not been obviated until the process of this invention which yields a product on which no ridge or indentation is available to entrap grit and dust. Even more practical, the structure can be readily cleaned with soap and water and any dirt which may collect incidentally can be rinsed off with ease.
Any suitable flexible foam may be used for the core of the structure to be prepared according to the process of this invention including foamed rubber, styrene, vinyl, polyester, polyether, polycarbonate and any other suitable natural or synthetic cellular plastic material. Preferably, however, the foam core is a flexible cellular polyurethane which can be prepared by reacting any suitable organic compound having at least two reactive hydrogen atoms as determined by the Zerewitinofl method with an organic polyisocyanate in the presence of a blowing agent. It is to be understood that any suitable active hydrogen containing organic compound and any suitable organic polyisocyanate can be used as well as any inert blowing agent which is a gas at the temperature of the reaction and all are contemplated. The polyurethane can be prepared by conventional methods such as, for example, the method described in US. Patent Reissue 24,514. The polyurethane foam can be a polyester-polyurethane, a polyether-polyurethane, a mixed product or the like. Other suitable processes for making polyurethane foams which can be used in practicing this invention are found in the art such as, for example, US. Patents 3,054,757; 3,061,556 and 3,067,148. Suitable polyether-polyurethane foams can be prepared by the processes disclosed in the art, including US. Patents 2,948,691; 3,094,495 and 3,044,971.
In one preferred embodiment of the invention, a flexible polyether-polyurethane foam prepared from toluylene diisocyanate is used in combination with a self-sustaining polyvinyl sheeting as the covering material.
Any suitable covering material which can be formed into a seam with the electronically energized agency discussed hereinafter may be used in the process of this invention. Some suitable materials include self-sustaining thermoplastic sheets of polyurethane, polyvinyl, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polyvinylacetate, copolymers of polyvinyl chloride and polyvinylacetate, rubber, polyethylene, polypropylene and the like. Preferably, however, a vinyl covering is employed. In all instances, the thermoplastic sheet or film is a self-sustaining film and can vary in thickness depending upon the use to which the finished product is to be put.
In practicing a preferred embodiment of this invention, a polyurethane foam block is .beveled or chamfered around its top and bottom edges and placed within a confining member having substantially the same length and width dimensions as the foam but having a smaller depth dimension. The confining member is lined with polyvinyl sheeting so that the edges of the lining form a flange or lip around the top and bottom of the confining member. In other words, the width of the lining is greater than the depth of the confining member. The confined block is covered top and bottom with a sheet of vinyl having length and width dimensions greater than those of the foam block, and disposed between two surfaces which can be electronically energized. These surfaces are brought together to compress the foam to the depth of the confining member, and are activated to electronically seal the vinyl sheets on the top and bottom of the confined block to the lip or flange of vinyl at the top and bottom edge of the confining member. The pressure is then released and the covered block is removed from the confining member. The excess vinyl is merely torn off of the structure at the weld to which a tear line has been imparted at its outer edge by the electronically energized agency, and a cushion having contoured edges and sturdy side seams is obtained.
The use of the electronically energized die permits the formation of a perfect seal or seam everytime with no necessity for heating the plastic material to form the seam and thereby weaken the thermoplastic sheeting immediately adjacent to the seam area which must of necessity also become heated somewhat in the process. This is an especially important consideration since the core of the product formed by the process of this invention is under a transverse compression held firm by the sealed covering material. If the strength of the covering material is impaired in the sealing process, the product will not withstand everyday wear and tear despite the strength of the seam and all of its other superior attributes.
Referring now to the drawing, FIGURE I shows, for the purposes of illustration, a rectangular block of foam 1 having its top and bottom edges 2 and 3 beveled by means of a profiled wire brush 4 energized by a mechanism shown at 6 so that it rotates. In this preferred mode of beveling the edges of the foam block, the corners are buffed off with the rotating brush at an angle or depth which will permit the final product to have the degree of contour or crown desired, although any other suitable means for imparting a chamfer to the top and bottom perimeters of the foam block may also be used. One of the most significant aspects of the process of this invention is that the foam being compressed within the boxing member does not bulge under the compressive force to overhang the edge of the boxing member and interfere with the seam being formed by the thermoplastic sheets. This innovation is possible only because of the beveling of the foam block core at an angle of at least about 15 with reference to the plane of the depth of the block. Furthermore, whatever the depth of the boxing member in relation to the depth of the foam block, no difliculty will be encountered with foam overhang if the angle of the chamfer begins at the top and bottom edge of the boxing member as shown in FIGURE II. It should also be mentioned here that the dimensions of the block may be any suitable dimensions to fit the exigencies of the occasion and the product desired and all lengths, widths and thicknesses can be treated as outlined herein.
FIGURE II shows the beveled block disposed within a confining member of a box ring die which is lined with flanged polyvinyl sheeting 8. A sheet of polyvinyl is disposed on the top and bottom of the foam block 9 and this whole construction is placed between two platens 11 and 12 containing an electronically energized .die. When pressure is applied to this setup at 13, for example, the foam is compressed to the depth of the confining member and the electronic die is activated to seal the covering sheets while the foam is compressed. The seal forms the seam or weld line 14 which is bounded by a tear line so that the excess vinyl can be torn away and an even seam or edge radius can be obtained on the finished product.
As shown in FIGURE III, with this method of high frequency fabrication a cushion 16 having contoured edges 17 and seams at the sides 14 can be readily prepared. In such a construction, the foam core which has been oha mfered around the top and bottom edges is maintained under a transverse compression by a seal between the sheets of vinyl at the top and bottom surfaces of the core and a strip of vinyl around the side of the core with the seal extending around the side of the cushion and spaced from the top and bottom surfaces thereof. In order that the structure may have breathing characteristics, a series of holes 18 may be made in the lining of the confining member before the seams are made although if desired, the perforations may also be made later.
It is clear that the degree of the crowning or contouring effect that is imparted to the finished product depends, in addition to the angle and depth of the beveled edge of the foam core, on the difference between the depth of the confining member and the depth of the foam core. That is, a much greater crown or contour will be obtained if the depth of the confining member is substantially smaller than that of the foam core than will be achieved if the depth of the confining member is only slightly smaller than that of the foam core. Again, the choice depends on the type of product desired and no limitation is contemplated.
Although the invention has been described in considerable detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for this purpose and that variations can be made by those skilled in the art without departing from the spirit and scope of the invention except as is set forth in the claims.
What is claimed is:
l. A process which comprises beveling the edges of a block of foam, disposing the beveled block within a confining member having substantially the same length and width dimensions but a depth less than that of said block, said con-fining member being lined with a flanged covering material, disposing the confined block between two sheets of covering material, compressing the block to the depth of the confining member between two surfaces, sealing the two sheets of covering material to the flanges of the lining of the confining member to fuse said sheets together, releasing the pressure and removing the block from the confining member to form a contoured seamed structure.
2. The process of claim 1 wherein the sealing is achieved by means of an electronically energized agency.
3. The process of claim 1 wherein the foam is a polyurethane.
4. The process of claim 1 wherein the covering material is a polyvinyl plastic.
5. The process of claim 1 wherein the edges of the block of foam are beveled by means of a rotating profiled brush.
6. The process of claim 1 wherein the angle of the bevel is at least about 15 with reference to the plane of the depth of the foam block.
References Cited UNITED STATES PATENTS 2,865,435 12/1958 Bramson et al. 5-337 XR 2,878,153 3/1959 Hacklander 156-163 2,870,824 1/1959 Le Barre 5-354 3,064,279 11/1962 Finkle 5-337 3,094,716 6/1963 Friedman 161-43 XR 3,262,136 7/1966 Sercik 5-353 3,118,153 1/1964 Hood 161-190 JOHN T. GOOLKASIAN, Primary Examiner I. D. SMITH, Assistant Examiner US. Cl. X.R.