METHOD AND APPARATUS FOR MAKING SELF-INFLATABLE MATTRESSES AND CUSHIONS

Abstract: A self-inflatable mattress (10) is formed from an open pore foam core (20) which has bonded thereto along the entire outer surface of the core dual melt films (22, 42) which are composed of a low melting point layer (S2) which contacts the foam core (20) and a high melting point layer (S1) which was disposed out of contact of the foam core. Heat and pressure are applied by a suitable means (26, 36, 38) to heat seal the dual films (22, 42) to the foam core (20). Provision is made to include a valve (16) in the self-inflatable mattress (10) which is in communication with the enclosed foam core (20).

Description: TITLE: METHOD AND APPARATUS FOR MAKTNG SELF-INFLATABLE MATTRESSES AND CUSHIONS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method and apparatus for making a self-mflatable air mattress or cushion having an adjustable firmness characteristic and the product formed thereby. 2. Description of Related Art The pπor art literature describes several early efforts to make self-mflatable mattresses and the like. For example, U.S. Patent 3,935,690 entitled "Method of Packaging and Unpackagmg a Self- Inflating Air Mattress" describes a mattress which can be used for camping and which includes an open cell foam core covered with a air impervious mateπal having a fabric exterior. Such mattresses are satisfactory for certain camping purposes but such mattresses tend to be thin and the edge of such mattresses tend not to be physically attached to the exterior coveπng material U.S. Patent 3,675,377 descπbes another typical inflatable structure including a flexible foam core portion and a fabric coveπng. The problem with structures such as described in U.S. Patents 3,675,377 and 3,935,690 is that the exteπor mateπal is not bonded to the entire surface of the foam core but, rather, acts like a bag so that when the structure is inflated the sides or edges tend to round out. Accordingly, it is virtually impossible to form a self-mflatable mattress, using pπor art techniques, which includes concavities or compound three-dimensional shapes. Fig. 1A illustrates, in cross-sectional detail, a typical pπor art self-mflatable mattress having a core and a covering. Because the coveπngs tend to be fabric, it is not possible to make a lap seam without losing air as shown m Figs. IB and lC. If the fabπc illustrated in Figs. IB and 1C is sealed on only one side, then air tends to escape m the manner indicated. Fig. IB illustrates a prior art "fin" seam and Fig. 1C illustrates a prior art "overlap" seam. It is also possible to make an overlap seam, such as illustrated in Fig. 1C, using fabric that is coated on both sides with a cement material between the two layers. Such prior art structures have several major disadvantages. First, and foremost, fabric covers, whether or not wholly or partially sealed on both sides, wrinkle when they turn corners and/or are compressed. Therefore, they cannot adequately conform to iπegular shapes and tend to leak. Second, it is not possible to form a satisfactory thermoplastic welded seal between two overlapping layers of single sided coated cloth material, such as illustrated in Fig. lC. Third, and last, the prior art techniques such as illustrated in Figs. 1 A -1C usually require adhesives or chemicals which are environmentally hazardous. Other inflatable mattresses or structures are unknown in the prior art. See, for example, U.S. Patent 1,970,803 which describes a method of making an inflatable rubber structure, such as a bed mattress. U.S. Patent 4,991,244 describes an air mattress that includes a means for controlling the density and the relative firmness thereof depending upon the side of the mattress being occupied. Similarly, note U.S. Patent 4,908,895. Lastly, U.S. Patent 4,167,432 entitled "Process of Making a Water Bed Mattress" describes a technique for forming a bag-like structure that can accept water and act as a suitable bed mattress. Fig. ID illustrates a sheet of commercially available dual melt film including a top surface SI having a melt temperature Tl and a bottom surface S2 having a melt temperature T2 which is lower than the melt temperature Tl on the top surface SI. Acceptable films are formed from polyether polyurethane. Such films are generally used for purposes other than making self-inflating air mattresses or cushions. While the prior art does describe a number of efforts to make self-inflating structures, such as mattresses and cushions, nevertheless, when those structures are inflated they tend to have a generally convex shape because the exterior fabric layer does not satisfactorily adhere to the entire foam core. In contrast, Applicant's invention completely adheres to the surface of the foam core thereby permitting larger structures, having a defined shape, and which includes concave and compound portions, flat sides and right angle edges. SUMMARY OF THE INVENTION Bπefly described, the invention compπses a method and apparatus for making self-mflatable mattresses and cushions having an open pore foam core and an exterior surface formed from dual melt films Initially, a core block of open pore foam mateπal is placed on a flat surface or conveyer belt and a top sheet comprising a layer of dual melt film is placed on top thereof so that the edges of the film drape over the sides of the core. A non-stick, heat transfer, buffer layer is then placed on top of the film so that the top layer of the film does not adhere to the heating agent which could compπse a conventional heating iron or a heat and pressure roller. The film has a top surface SI having a first melt temperature Tl and a bottom surface S2 having a melt temperature T2 which is lower than the melt temperature Tl of the top surface SI. Heat TR and pressure, preferably from a roller, are then applied to the top sheet The heat of TR is such that the bottom layer S2 of the dual melt film melts and adheres to the foam core but the top layer SI does not melt. A pair of heated pressure rollers apply heat, through another buffer layer, to the side portions of the top layer that overlap the edge of the foam core so that the entire top sheet adheres to the foam core leaving only small corner tails to be folded in later and sealed The foam core is then turned over and a bottom layer of dual melt film is placed on top of it so that its sides drape over the edges of the block and heat and pressure are again applied, through a buffer layer, preferably with a roller, to cause the bottom layer to adhere to the bottom of the foam core. The same pair of side pressure rollers causes the edges that drape over the foam core to adhere to the sides of the core and to the top layer. The tails, or ears, of both sheets are folded m so that they melt and attach to the block. A valve, which can be either an oral inflation valve or one way valve, is then attached to the side of the mattress The dual melt film completely encases and contacts the outer surface of the foam core. The mattress can then be squeezed and deflated and kept in that position for easy storage Subsequently, when it is desired to inflate the mattress, the valve is opened and the mattress naturally assumes its oπg al shape. Because the dual melt film completely encases the entire core, it is possible to form very rigid structures which may include concave indentations or compound three-dimensional forms. Such structures could include, for example, mattresses for beds, seat cushions, back cushions, and special purpose cushions, such as pilot ejection seat cushions. The invention has several other advantages over the pπor art. First, because fabπcs are not used, the outer cover does not wπnkle and leak. The dual melt film is relatively soft when applied to the open foam core and conforms to the entire surface thereof. Even though the bottom surface S2 melts, the top surface is relatively soft so that it stretches and conforms to the foam shape whereas cloth is stiff and does not When the final product is formed, the dual melt film, after it cools, also stretches and moves with the foam core so that it does not wrinkle or pucker and thereby adheres to the basic shape of the foam core when inflated to ambient air temperature or when pressuπzed. Second, the overlapping end seams are bonded by a weld between the bottom surface S2 of one sheet of film and the top surface S 1 of the abutting sheet of film. The result is a seal that not only adheres entirely to the edge of the foam core but also adheres to itself in an absolutely airtight fashion. Third, and very importantly, because only heat and pressure is used to laminate the dual melt films together and to the core, the use of adhesives, solvents and hazardous chemicals is avoided. These and other features of the invention will be more fully understood by reference to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a partial, cross-sectional view of a pπor art self-inflating mattress showing the air gap at the end thereof. Fig IB illustrates the problem of trying to laminate two fabnc mateπals together m a fin seal without losing air at the point of lamination. Fig. 1C illustrates the same dilemma when an overlap seam is made, namely that air tends to escape through the laminated portion Fig. ID illustrates a small section of commercial dual melt film having a top surface SI with a melt temperature Tl and a lower surface S2 with a melt temperature T2 lower than temperature Tl . Fig. 2A illustrates the preferred embodiment of the mattress invention m its compressed and rolled up state. Fig. 2B illustrates the invention as it self-inflates and the air valve is open. Fig. 2C illustrates the invention m its fully self-inflated state with the air valve closed. Fig. 3 A illustrates the first step of the preferred method of forming the self-mflatable mattress comprising placing a top sheet of dual melt film on top of a block of open pore core material. Fig. 3B illustrates the second step of the method in which a non-stick, heat transferable, buffer layer is placed on top of the top layer of dual melt film. Fιg.3C illustrates the third step of the method where a roller applies heat and pressure to the buffer layer causing the heat to melt the bottom layer S2 of the dual melt film which, in turn, adheres to the top surface of the foam core. Fig. 3D illustrates the fourth step in which a pair of heated pressure rolls causes two sides of the top sheet to adhere to the foam core. Fig. 3E illustrates the fifth step of the invention in which the remaining two sides of the top sheet are caused to adhere to the foam core by a pair of heated pressure rollers. Fig. 3F illustrates the sixth step of the method in which the foam core is inverted and a bottom sheet of dual melt film is placed on top thereof. Fig. 3G illustrates the seventh step of the method in which a non-stick, heat transferable, buffer layer is placed on top of the bottom sheet of dual melt film. Fig. 3H illustrates the eighth step of the method in which a roller applies heat and pressure to the buffer layer causing the heat to transfer to the dual melt film which, in turn, melts and adheres to the bottom of the foam core. Fig. 31 illustrates the ninth step of the method in which a pair of side rollers causes the overlapping edges of the bottom sheet to adhere to the bottom surface of the foam core and to the overlapping edges of the top sheet. Fig. 3J illustrates the tenth step of the method in which the remaining two sides of the bottom sheet are caused to attach to the foam core and the side portions of the top layer by a pair of heated pressure rollers. Fig. 3K illustrates the eleventh step of the method in which an air inflation hole is created in the side of the mattress and a base patch is attached thereto. Fig. 3L illustrates the twelfth step of the method compπsmg attaching a valve to the air inflation hole Fig. 4A is a side elevational view of a machine that can accomplish the steps of the preferred embodiment of the method as illustrated in Figs. 3 A - 3L. Fig. 4B is a top plan view of the machine illustrated in Fig. 4A. Fig. 5 A illustrates a seat cushion embodiment having a pair of concave indents therein. Fig. 5B illustrates a plug embodiment. Fig. 5C illustrates a cushion having an aperture therein for receiving the plug illustrated in Fig 5B. Fig. 5D illustrates an L-shaped cushion embodiment. Fig. 5E illustrates a partially semi-circular embodiment of a cushion. Fig. 5F illustrates a corner, or edge, shaped cushion. Fig. 5G illustrates a cushion that could, for example, compπse a backrest including a base portion and an oblique back portion attached thereto. Fig. 6A is a top plan view of an alternative core embodiment in which the outside portion of the core has a higher density than the inside portion thereof. Fig. 6B is a cross-sectional view of the dual density core illustrated in Fig. 6A Fig. 7A is a top plan view of another alternative, dual density foam core suitable for use as a seat cushion. Fig. 7B is a cross-sectional view of the dual density core illustrated in Fig. 7A. Fig. 8A illustrates a dual mattress embodiment in which two separate self-inflatable mattresses abut each other and are connected together by one or more valves. Fig. 8B illustrates an alternative dual mattress embodiment in which two separate self- inflatable mattresses abut each other and are attached directly to each other but in a non- communicating fashion and in which the two separate self-inflatable air mattresses have separate self-inflation valves. DETAILED DESCRIPTION OF THE INVENTION During the course of this descπption, like numbers will be used to identify like elements according to the different figures that illustrate the invention. The preferred embodiment 10 of the invention is illustrated in progressive Figs. 2A - 2C. In Fig. 2A the self-mflatable mattress 10, according to the preferred embodiment thereof, is shown m the collapsed state pπor to self-inflation and expansion. In the collapsed state, all of the air has been squeezed out of the mattress and the valve 16 is closed m the evacuated state so that the mattress volume is substantially reduced by at least 50-80%. If the valve 16 is opened as shown m Fig. 2B, air is drawn m and the top surface 12 and the sides 14 begin to assume a relatively flat shape. The mattress 10 is illustrated m its fully inflated state in Fig. 2C. Valve 16 is preferably a oneway valve but could be a valve that permits oral inflation. By adjusting the amount of air that enters the mattress 10 through valve 16, it is possible to control the firmness of the mattress 10. The mattress 10 is preferably formed according to the basic steps illustrated m Figs. 3 A - 3L A block of open pore polyether foam 20 comprises the middle of the mattress. Foam core 20 can be substantially thicker than prior art self-inflating mattresses. There are several commercially available polyether foams that could be used for the core 20. In particular, grades 3100HXXX and 32850XXX work well and have the following specifications: POLYETHER FOAM GRADE: 3100HXXX TEST VALUES TYPICAL Density, lbs./cubic feet 1.0 Indentation Force Deflection 25% DefL , 4" 10 Tensile Strength, psi 12 Ultimate Elongation, % 200 Tear Resistance, ppi 2.0 Combustibility PASSES CALIFORNIA TECH> BULLETIN #117 Sample Size: 15"xl5"x4" POLYETHER FOAM GRADE: 32850XXX TEST VALUES TYPICAL Density, lbs./cubic feet 1.0 Indentation Force Deflection 25% DefL, 4" 18 Tensile Strength, psi 15 Ultimate Elongation, % 200 Tear Resistance, ppi 2.0 Compression Set 50%, 22 hrs 158° F 10 Max. Sample Size: 15"xl5"x4" Reported values are taken from the middle of the middle of a test block. The test method is in accordance with ANSI/ASTM-D-3574-91. According to the first step illustrated in Fig. 3 A, a sheet of dual melt film 22 is placed on top of the foam core 20. The most important characteristic of dual melt film 22 is that it has a top surface SI with a melt temperature Tl and a bottom surface S2 with a melt temperature T2 which is lower than Tl . See Fig. ID. There are several dual melt films that are acceptable. In particular, Yellow 3012 or Clear 3009 film available from Highland Industries, Inc., 225 Arlington Street, Framingham, Massachusetts 01702 produce acceptable results. The characteristics of those two dual melt films are as follows: PRODUCT: Yellow 3012 film on Clear 3009 film KEY PROPERTIES: A two layer, airholding, heatsealable, low melt/high melt film combination 3012 Film 3009 Film Type: Polyether Polyurethane Polyether Polyurethane Color: Yellow Clear Thickness: 2.0 mils 1.8 mils Vicat Softening Point: 72 degrees Celsius 120 degrees Celsius Melt Index: 50* 5** g/10 minutes @190 degrees Celsius, 8.7 kg g/10 minutes @210 degrees Celsius, 3.8 kg PUT UP: Core Size: 1.5" or 3" Width Tolerance: +/- .25" Slit Width: As specified per factory order Roll Length: 100 yds PHYSICAL PROPERTIES: TEST TYPICAL RESULTS TEST PROCEDURE Weight: 3.2 oz/sq. yd. FED STD 191a Method 5041 Thickness: 3.8 mils ASTM D 3767 In Fig. 1, the bottom surface S2 with the lower melting temperature T2 contacts the upper surface of the open core block 20 so that the top surface SI having the higher melt temperature Tl faces outward. The second step of the method is illustrated in Fig. 3B. A non-stick, heat transfer, buffer sheet or layer 24 is placed on top of the dual melt film 22. There are a variety of buffer materials 24 that are acceptable such as: TFE-GLASS™ (nominal .003" series) fabric such as manufactured by Taconic, P.O. Box 69, Coonbrook Road, Petersburgh, NY 12138. In particular, the TFE-GLASS™ Product No. 7038 was found to be quite satisfactory. It has the following characteristics: The third step of the method is illustrated in Fig. 3C. A heated roller 26 is brought down with a force P illustrated by arrow 28. Roller 28 is heated to a temperature TR as illustrated by arrows 30. The combination of the heat 30 and the pressure 28 causes the heat 30 to be forced through the buffer layer 24 and the upper layer SI of the dual melt sheet 22 and to the bottom layer S2 which melts and attaches itself to the top surface of the foam core 20. The temperature TR of the heat 30 from the roller 26 is lower than the melt temperature Tl of the top surface S 1 of the dual melt film 22 but higher than the melt temperature T2 of the bottom layer S2 so that the bottom layer becomes sticky and adheres to the top layer of the foam core block 20 yet the top layer SI remains relatively solid and air impervious. The fourth step of the method is illustrated in Fig. 3D. A pair of side buffer layers 32 and 34, having non-stick, heat transfer characteristics substantially identical to those of buffer layers 24 is interposed between rollers 36 and 38 and foam core 20. Right side heat and pressure roller 36 applies heat and pressure to the buffer layer 32 which, in turn, heats the overlapping portion of the dual melt sheet 22 causing it to adhere to the foam core 20. Similarly, a left side heat and pressure roller 38 contacts the buffer sheet 34 and causes the overlapping dual melt film 22 to adhere to the other side of the foam core block 20. Tails, or dog-ears, 40 are formed from the excess mateπal 22 that does not get attached to the sides of the block 20 during the first pass. The next, or fifth, step in the process is illustrated in Fig. 3E. The block 20 is rotated 90° and the tails 40 are tucked inward. Pressure and heat from rollers 36 and 38 are transferred through buffer layers 32 and 34 to the remaining overlapping portions of the upper dual melt sheet 22 and the folded m tails 40 are sealed in that position m a manner similar to that described with respect to Fig. 3D. The sixth thorough tenth steps illustrated m Figs 3F - 3J are essentially identical to the first through fifth steps illustrated in Figs. 3 A - 3E except that they are repeated with the foam core 20 turned upside down. According to the sixth step illustrated in Fig. 3F, the core 20 and top sheet 22 are turned upside down and a second, or bottom, sheet of dual melt film 42 is placed on top thereof. The bottom surface S2 having the lower melt temperature T2 contacts the bottom, or exposed portion of the foam core 20 so that the upper surface SI having the higher melt temperature Tl faces outward. The seventh step of the method is illustrated m Fig. 3G. A buffer sheet 24, identical to the one illustrated m Fig 3B, is placed on top of the bottom dual melt film 42. The eighth step of the method is illustrated in Fig. 3H. Heated pressure roller 26 applies pressure 28 and heat 30 to the buffer layer 24. The temperature TR of the heat 30 of the roller 26 is transferred through the buffer layer 24, and the top layer SI of the dual melt film 42, to the bottom layer S2. Since the heat TR is greater than T2 but less than Tl, the bottom layer S2 of the dual melt film 42 melts and adheres to the bottom of the foam core 20. The ninth step of the method, illustrated in Fig. 31, compπses sealing two of the four sides of the sheet 42 to the block 20 A pair of non-stick, heat transfer buffer layers 32 and 34 are placed adjacent the overlapping material of the dual melt film 42. A left side heat and pressure roller 36 contacts the buffer 32 and causes the overlapping portion of the dual melt film 42 to adhere to the side of the core 20 Similarly, the left side heat and pressure roller 38 heats the overlapping portion of the film 42 causing that portion to adhere to the side of the foam block 20 and leaving a set of tails, or dog-ears, 44 The tenth step of the method is illustrated in Fig. 3J. The core 20 is rotated 90° and the remaining two overlapping portions are sealed to the remaining edges of the core 20. It is also important to note that the bottom portion 42 illustrated m Figs. 31 and 3J, adhere not only to the foam block 20 itself but also to the tails 44 and to the overlapping portion of the top dual melt film 22 so that the mattress illustrated m Fig. 3 J is entirely hermetically sealed with all sides, convex, concave or compound, contacting the dual melt film 22 or 42. The eleventh and twelfth steps of the method of fabπcatmg the mattress 10, as illustrated m Figs 3K and 3L, comprise placing a valve 16 on the mattress 10 and m communication with the mteπor open pore, foam core 20. As previously discussed, valve 16 can be a one-way valve with or without a cap or a valve suitable for oral inflation. Valves 16 such as described here are available commercially The eleventh step of the method illustrated in Fig. 3K compπses punching a hole 46 through one side of the mattress 10. Next, a round patch 48 is preferably placed over the hole 46 to provide a base for valve 16 Patch 48 can be attached adhesively or by means of heat, depending upon the materials used The twelfth, and final, step of assembly is illustrated m Fig. 3L. The valve 16 is placed over patch 48, which also has a hole punched through it, and attached in that position with heat or adhesive It may also be desirable to place another patch 48 with a hole therein over the valve stem 16 for additional strength and support. A machine 50 that can be used to accomplish the twelve steps illustrated in Figs. 3A - 3L, is illustrated m Figs. 4A and 4B. A film roll support stand 50 holds a roll of dual melt film 54 which can be dispensed over the foam core 20. Foam core 20 is supported by a conveyer belt 56 traveling m the direction of arrow 66 which, m turn, is supported by a conveyer belt support stand 58 The block 20 with the dual melt film 54 placed on top thereof passes under the top heat and pressure roller 26 as oπginally descπbed with respect to Figs. 3A - 3C and 3F - 3H. After the top sheet 22 or bottom sheet 42 has been attached to the block 20, the combination passes through heated side pressure rollers 36 and 38 which cause the sides of the dual melt film to adhesively attach to the core 20 as illustrated in Figs. 3D, 3E, 31 and 3J. A first pair of sides is usually heated first as illustrated in Figs. 3D and 31, then the block is rotated 90°, as indicated by arrow 64, and the remaining two sides are heated under pressure as illustrated m Figs. 3E and 3J After the core 20 has been completely encased in dual melt film 22 and 42, as illustrated in Fig 3J, a hole 46 is punched in the side by pm 60 located in the center of conveyer stop 62 While the prefeπed embodiment of the invention is directed primarily towards a mattress 10. it can be used to produce a variety of other mattress or cushion devices having concave, convex or compound shapes. For example, Fig. 5 A illustrates a possible cushion 100 having a pair of indented or concave portions 108 and an inflation valve 16. Fig. 5B illustrates a cylindrical plug 102 having a relatively rigid shape m its expanded form Cylindncal plug 102 is easily received in aperture 106 in a complimentary cushion 104 illustrated in Fig 5C An L-shaped foam cushion 110 is illustrated in Fig. 5D and includes a significant side indent therein Fig. 5E illustrates a semi-circular or semi-round cushion 112 having one rounded side and one relatively flat side. An end, or corner, cushion 114 is illustrated m Fig. 5F and includes one rounded side and two relatively flat sides Lastly, a three-dimensional cushion 116, which might compπse, for example, a backrest, includes a base portion 118 and a back portion 120. All of the cushions illustrated in Figs. 5A - 5G can be collapsed and evacuated to a size that is, perhaps, 50-80% of their inflated size for ease of storage The user thereafter merely has to open valve 16 to permit the air to naturally come and fill the cushion. Alternatively, the user can orally inflate the valve 16 and manually adjust the valve so that the stiffness of the cushion can be selectively modified according to the needs of the user. An alternative embodiment of the invention comprises the use of a mattress foam core 130 having dual density as illustrated in Figs. 6A and 6B. According to alternative embodiment 130, the mattress core includes a denser outer portion 132 and a softer central portion 134. The denser outer portion 132 helps guarantee that the mattress 10 retains a crisp, well defined exteπor shape. Another alternative embodiment 140 is illustrated in Figs. 7 A and 7B. Alternative embodiment 140 comprises the core of a seat cushion having a dual density m which the outer portion 142 has a higher density than the softer, inner portion 144. Inner portion 144 is not only of a lower density but also is slightly indented to fit the natural contours of the human buttocks. One major advantage of the present invention is that the dual melt film adheres to substantially 100% of the exteπor surface of the foam core thereby permitting the ultimate mattress 10 or cushion to assume a variety of well defined concave, convex, or compound shapes. Lastly, Fig. 8B illustrates an alternative embodiment 150 of the invention in which two independently self-mflatable mattresses, sections 152 and 154, are connected together by a pair of valves 156. The firmness of the respective two sides 152 and 154 of the combined king size mattress 150 can be independently adjusted by controlling the flow of air through valves 156. It may also be desirable to cover the exteπor of the mattress 150 or any of the other cushions or mattresses descπbed herein with a fabric or cloth material for improved strength and durability. Fig. 8B illustrates an alternative embodiment 160 of the dual mattress concept. Embodiment 160 comprises a pair of identical self-mflatable portions 162 and 164 connected to, and abutting each other, at seam 166. Unlike embodiment 150 of Fig. 8A, there is no internal communication between mattress compartments 162 and 164. Instead, each individual mattress compartment 162 and 164, respectively, has an individual self-inflation valve 168 and 170. Therefore, either side of the mattress may be independently and selectively controlled for firmness depending upon the setting of vales 168 and 170 or the pressuπzation thereof. There are alternative means and methods for applying heat and pressure to the dual melt film and the underlying open pore foam core other than heated, pressurized rollers For example, a large flat heated iron press could be employed or, alternatively, a hot air blow dryer could achieve some of the same results. While specific heating and pressuπzmg techniques have been descnbed in this disclosure, it will be appreciated by those of ordinary skill in the art that other heating and pressuπzmg techniques might also be suitable. While the invention has been described with reference to the preferred embodiment thereof, it will be appreciated by those of ordinary skill m the art that modifications can be made to the method and apparatus for forming the mattress and cushion, or the mattress or cushion itself, without departing from the spirit and scope of the invention as a whole.

Claims: WHAT IS CLAIMED IS: 1. A method of making a self-inflatable apparatus (10) from a core (20) of open pore foam, comprising the steps of: a. substantially surrounding said core (20) with a film (22, 42) having a first surface (SI) that melts at a first temperature Tl and a second surface (S2) that melts at a second temperature T2 which is lower than Tl and such that the second surface (S2) substantially contacts the entire exterior surface (12) of said core of open pore foam (20); and, b. heating said first surface with a heating means (26, 36, 38) to a temperature TR lower than Tl but higher than T2 so that said second surface (S2) melts and adheres to substantially the entire exterior surface (12) of said core of open pore foam (20). 2. The method of claim 1 further comprising the step of: c. attaching a valve means (16) to said apparatus (10) for selectively communicating air to the interior of said core of open pore foam (20), wherein said apparatus (10) may be deflated by squeezing the air out of said foam (20) and valve means (16) and wherein said apparatus (10) will automatically self-inflate afterwards due to the resilient characteristics of said foam (20) and said thermoplastic film (22, 42). 3. The method of claim 1 further comprising the step of: d. placing a buffer means (24, 32, 34) between the heating means (26, 36, 38) and the first surface (SI) during said heating step b in order to prevent the heating means (26, 36, 38) from sticking to the film (22, 42). 4. The method of claim 3 comprising the step of: e. applying pressure (P, 28) to said first surface (12) during said heating step b above. 5. The method of claim 4 wherein said heating means comprises a roller (26, 36, 38). 6. The method of claim 5 wherein said film (22, 42) comprises at least two sections of film. 7. The method of claim 1 further comprising the step of: f. attaching a valve means (16) to said apparatus (10) for selectively communicating air to the interior of said core of open pore foam (20), wherein said apparatus (10) may be internally pressurized through said valve means (16) and substantially retain its external shape. 8. An apparatus (50) for making a self-inflatable device (10) from a core of open pore foam (20) and a film (54) having a first surface (SI) that melts a first temperature Tl and a second surface (S2) that melts at a second temperature T2 which is lower than Tl and such that the second surface (S2) substantially contacts the entire exterior surface (12) of said core of open pore foam (20), said apparatus (50) comprising: heating means (26, 36, 38) for heating said first surface (SI) to a temperature TR lower than Tl but higher than T2 so that said second surface (S2) melts and adheres to substantially the entire exterior surface of said core of open pore foam (20); and, pressure means (26, 36, 38) for applying pressure to said heating means against said film to ensure that said second surface (S2) of said film (22, 42) melts and adheres to said core of open pore foam (20). 9. An apparatus (50) for making a self-inflatable device (10) from a core of open pore foam (20) comprising: a means (52) for dispensing a sheet of film (54) having a dual melt characteristic such that its top surface (SI) melts at a temperature Tl and its bottom surface (S2) melts at a temperature T2 which is less than Tl ; a first roller means (26) for applying heat and pressure to said dual melt film (54) to cause it to adhere to said core of open pore foam (20); at least a second roller means (36, 38) for applying heat and pressure to said film (54) to cause said film (54) to adhere to a different surface of said core (20); and, conveyer means (56) for conveying said core (20) and said film (54) from said first roller means (26) to said second roller means (36, 38). 10. The apparatus ( 10) of claim 9 further comprising: a non-stick, heat transferable, buffer means (24, 32, 34) locatable between said roller means (26, 36, 38) and said core (20) for preventing said roller means (26, 36, 38) from sticking to said film (54). 11. The apparatus of claim 10 further including: a puncture means (60) for puncturing said film (54) located downstream of said second roller (36, 38) means. 12. The apparatus (10) of claim 11 wherein said second roller means comprises at least a second (36) and a third roller (38) for applying heat and pressure to opposite sides of said foam core (20). 13. A self-inflatable apparatus comprising: a core of open pore foam (20) having a top (12), a bottom, and at least one side (14); a film (22, 42) surrounding said foam (20), said film having a first surface (SI) having a first melting temperature Tl and a second surface (S2) having a second melting temperature T2 lower than Tl and wherein said second surface (S2) has at least partially melted and attached itself to the exterior surface of said core (20); and, a valve means (16) passing through said film for selectively communicating air from the outside of said apparatus (10) to said foam core (20). 14. The apparatus of claim 13 wherein second surface (S2) of said film (22, 42) is attached to substantially the entire exterior surface of said foam core (20). 15. The apparatus of claim 14 wherein said foam core (130, 140, 142) is formed from at least a first (132, 142) and a second foam material (134, 144) and wherein said first foam material (132, 142) has a greater density than said second foam material (134, 144). 16. The apparatus of claim 15 wherein said first foam material (132, 142) surrounds said second foam material (134, 144). 17. The apparatus of claim 16 wherein said valve means (16, 168, 170) comprises a one-way valve (16, 168, 170). 18. The apparatus of claim 17 wherein said valve (16, 168, 170) means comprises an oral inflation valve (16, 168, 170). 19. The apparatus of claim 14 wherein said apparatus comprises a mattress (10, 130, 152, 154, 162, 164). 20. The apparatus of claim 14 further comprising: at least a second self-inflatable apparatus (154, 164); and, communication means (156) for selectively permitting air to pass between said second self-inflatable apparatus (154, 164) and said first self-inflatable apparatus (152, 162). 21. The apparatus of claim 14 further comprising: a fabric material adhered to said surface (SI).

Inventors: SWITLIK STANLEY, SWITLIK, STANLEY
Applicants: SWITLIK PARACHUTE CO INC, SWITLIK PARACHUTE CO., INC.
Application year: 1999
Main classification: A47C27
IPC codes: A47C27