Abstract:
Methods and techniques for constructing inflatable objects are detailed herein. Objects made according to these techniques may include both plastic material (such as polyvinyl chloride) and fabric connected indirectly via an interfacing material including the two. The objects additionally may include a fastening system including opposed, spatially-alternating loops through an article is placed. Use as inflatable sleds may (although need not necessarily) be the intended function of the objects.

Description:
REFERENCE TO PROVISIONAL APPLICATION 
     This application is based on and hereby refers to U.S. Provisional Patent Application Serial No. 60/304,701, filed Jul. 11, 2001, having the same title as appears above. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to items having inflatable portions and more particularly to inflatable sleds, watercraft, and other objects and methods and techniques for their construction. 
     BACKGROUND OF THE INVENTION 
     Numerous inflatable objects, including products intended for pleasure use in swimming pools or to be towed behind watercraft, are formed of plastics material such as polyvinyl chloride (PVC). Frequently, inflatable chambers or containers are formed by connecting multiple sheets of PVC and sealing the connected portions. Such sealing often occurs through welding, using ultrasonic or radio frequency (RF) energy (or otherwise), the relevant portions of the sheets. 
     PVC generally welds well to PVC and certain other plastics. It does not, however, typically weld well to numerous other materials such as fabrics. Sewing PVC to fabric similarly produces poor results, as stitching through PVC, particularly when it is in thin-sheet form, may cause the PVC to rip or otherwise lose its ability to retain air. 
     In some instances, inflating chambers of recreational objects to substantial pressures and covering them with shells might desirably enhance the rigidity of the overall products. The shells might not contain ordinary zippers, however, at least in part because the substantial pressures impinging upon the zippers could deform them and inhibit satisfactory operation (particularly in cold temperatures). Although conceivably heavy-duty zippers could be employed, such zippers also might not work correctly and, at minimum, would add significant expense to the cost of constructing the objects. 
     SUMMARY OF THE INVENTION 
     The present invention provides alternative methods and techniques for constructing inflatable objects. Objects made according to the invention may include not only PVC and fabric, but also an interfacing material of PVC and meshed fabric. In constructing these objects, the PVC may be welded to the interface and the fabric sewn to it, permitting use of both PVC and fabric in the same object. 
     Additionally optionally included in some products of the present invention are opposed, spatially-alternating loops through which a rope, stick, or other article may be placed. The loop sets, together with the article placed through them, provide a low-cost fastening system as an alternative to heavy-duty zippers. Preferably designed to be sewn to fabric components of the objects, the loops are especially (although not exclusively) useful in constructing inflatable sleds intended for use in cold weather. 
     By covering most or all of an inflatable bladder or chamber with a fabric shell, a relatively rigid object may be formed. Attaching the chamber to the shell using the interfacing material facilitates construction of the object. Certain fittings made of PVC or similar material, which otherwise might be connected to the inflatable chamber were it not covered by the shell, may instead likewise be connected to the exterior of the shell using the interfacing material. 
     It thus is an object of the present invention to provide techniques and methods for constructing inflatable objects. 
     It is an additional object of the present invention to provide components of inflatable objects in which PVC and fabric need not be welded together directly. 
     It is a further object of the present invention to provide methods of attaching PVC and fabric, such methods including use of interfacing material formed of PVC and meshed fabric. 
     It is yet another object of the present invention to provide fastening systems as alternatives to using heavy-duty zippers for products including inflatable portions. 
     It is also an object of the present invention to provide inflatable sleds and watercraft and methods and techniques for constructing them. 
     Other objects, features, and advantages of the present invention will be apparent to those skilled in the art with reference to the remaining text and the drawings of this application. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of selected components of an inflatable object of the present invention. 
     FIG. 2 is a perspective view of the components of the object of FIG.  1 . 
     FIG. 3 is a schematicized view of a fastening system of the present invention useful in connection with objects including (but not limited to) that of FIG.  1 . 
     FIG. 4 is a perspective view of an alternative object of the present invention. 
     FIG. 5 is a top plan view of an object similar to that of FIG.  4 . 
     FIG. 6 is a partially schematicized, cross-sectional view of a portion of the object of FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     Detailed in FIG. 1 is an exemplary object  10  of the present invention. Object  10  depicted in FIG. 1 is especially suitable for use as a snow sled and is configured as such. The constructions and techniques of the invention are useful for and applicable to other items, however, and are not limited either to snow sleds or to the object  10  illustrated in FIG.  1 . 
     As shown, object  10  comprises chamber  14 , cover  18 , and interface  22 . Chamber  14  typically is inflatable (with air or other appropriate fluid) and made of plastic material substantially impervious to passage of the inflation fluid. PVC is a preferred choice of material from which chamber  14  is formed, although those skilled in the art will recognize that other materials may be used instead. Likewise, although only one chamber  14  is shown in FIG. 1, object  10  may include more than one inflatable portion. 
     Cover  18  may form the base of object  10 , providing (among other things) the lower surface  24  of object  10  bearing on the snow, ice, ground, water, or other surface which the object  10  contacts in use. Cover  18  hence advantageously is formed of heavy-duty fabric such as (but not necessarily) polyester or nylon designed to withstand substantial frictional-contact wear. Although materials other than fabric may be used for cover  18 , the cover  18  typically is not made of PVC sheets, for example, as PVC tends to tear or break when subjected to certain types of frictional contact. Cover  18  additionally surrounds and houses much of chamber  14 , principally to protect the material of chamber  14  in use from undesired contact with the ground or other surfaces and to enhance the overall rigidity of object  10 . 
     Not illustrated in FIG. 1 are various fins, rudders, or other bearing materials that may be attached to or incorporated into lower surface  24  of object  10 . Such fins, rudders, and other devices may improve the handling characteristics or performance of object  10  as a sled or other product, but need not necessarily form part of object  10 . Likewise not illustrated in FIG. 1 are various fittings (such as but not necessarily hand grips) optionally included with cover  18 . FIG. 1 does, however, depict ring  26 , which if present may be used to attach a rope or line for pulling object  10  forward. 
     Interface  22  facilitates connection of chamber  14  and cover  18 . PVC and conventional fabrics do not adhere well when common techniques for welding plastics are employed. Likewise, although conventional fabrics may be sewn successfully to certain other materials, PVC typically is not one of them. Indeed, the PVC sheets often used in creating inflatable recreational products are likely to rip or lose their air-retaining capacity if subjected to sewing. 
     Accordingly, interface  22  constitutes means for connecting chamber  14  and cover  18  indirectly. Referred to in FIG. 1 as a “tarpaulin,” interface  22  preferably comprises a combination of PVC and meshed polyester (or nylon) fabric. Such interface  22  may be formed by melting the PVC so that it flows around the strands of the meshed fabric, effectively adhering to itself. Indeed, in some versions of object  10 , interface  22  is created by placing a layer of PVC on each side of a fabric layer and then heating (at least) the PVC. Doing so effectively forms a composite structure as the PVC flows around the strands of the meshed fabric and adheres to other PVC. 
     In use, interface  22  indeed may be welded to chamber  14  and sewn to cover  18 , thus connecting the two without directly welding or sewing them together. FIG. 2 illustrates an exemplary result of this connection, producing an object  10  in the form of a sled. Use of interface  22  is not limited to sleds, however, but rather may occur whenever adequate to facilitate connection of a plastic material to a fabric. 
     FIG. 3 illustrates, somewhat schematically, another aspect of the present invention. In it, cover  18  is depicted as at least partially enclosing or surrounding an inflatable component  30 , consistent with the description of the exemplary object  10  previously provided. In some embodiments of the invention, inflatable component  30  is the same as inflatable chamber  14 . Particularly when object  10  is used in cold weather (as a sled, for example), the combination of inflation pressure of component  30  and the low temperature could inhibit successful use of, for example, many zippers with cover  18 . (Indeed, at sufficiently high inflation pressure and low temperature, some zippers are likely to break and hence malfunction.) Nevertheless, being able to access and, if necessary, remove component  30  from cover  18  may be desirable in some circumstances, as when component  30  requires repair or replacement. 
     Thus, the invention optionally also contemplates attaching one or more loops to abutting edges or other portions of cover  18 . FIG. 3 shows, as an example, two such edges  34  and  38 . Sewn (or otherwise attached) to each edge  34  and  38  is a set of one or more loops  42 , with their respective receiving portions  42 A and  42 B able to be offset spatially in use. Viewed from left to right in FIG. 3 are multiple loops  42 , with receiving portions  42 A (for loops  42  attached to edge  34 ) alternating with receiving portions  42 B (for loops attached to edge  38 ). 
     Received by portions  42 A and  42 B is rope  46 , which if its ends are knotted or tied provides a zipper-less assembly for fastening edges  34  and  38  of cover  18 . Of course, those skilled in the art will recognize that articles other than rope  46  (such articles including but not limited to an appropriately-configured stick or rod) may be used instead, and that loops  42  may be configured or numbered differently than as illustrated in FIG.  3 . Generally, however, this portion of the invention mandates at least one retainer being attached to each of two opposing portions of cover  18  so that the retainers likewise oppose and are offset (or offsettable) spatially to receive an elongated object seriatim when the object is slid into the retainers. Such a system is particularly useful for sleds of the present invention, as its fastening capabilities are not significantly adversely affected in many high-pressure, low-temperature situations. 
     Any of chamber  14 , cover  18 , or interface  22 , finally, may include one or more fittings. FIGS. 1-2 illustrates fittings  50  present on exterior  54  of chamber  14 . Although the illustrated fittings  50  are hand grips, alternative or additional fittings  50  may be present. FIGS. 1-2 also show valve  58  for inflating or deflating (or both) chamber  14 . Valve  58  may be a simple plugged opening, a Boston valve, or any other suitable device, and more than the single valve  58  shown in FIGS. 1-2 may be employed as desired. 
     FIGS. 4 and 6 illustrate an alternative object  10 ′ of the present invention. As shown in these drawings, object  10 ′ is a watercraft, and more particularly a flat-topped boat referred to herein as a “deck kayak.” However, as noted earlier in connection with object  10 , object  10 ′ too is exemplary of products consistent with the present invention and need not be configured identically as depicted in FIGS. 4-6. 
     FIG. 6, especially, details a preferred structure of object  10 ′. Included as part of this preferred object  10 ′ are one or more inflatable chambers  14 ′, cover  18 ′ (preferably, but not necessarily, made of nylon or polyester), and material  22 ′, which may be formed if desired in the same manner as interface  22  is created. Cover  18 ′ typically surrounds most or all of chambers  14 ′ to protect the chambers  14 ′ in use. Chambers  14 ′ additionally may be removable from within cover  18 ′ if desired. 
     Further illustrated in FIG. 6 is that material  22 ′ may form the lower surface  24 ′ of object  10 ′, contacting principally cover  14 ′. Material  22 ′ may be sewn to cover  14 ′ or otherwise appropriately attached to it. In this configuration, material  22 ′ functions as the principal external contact or bearing surface when object  10 ′ is in use. 
     FIG. 4 shows other aspects of the exemplary deck kayak of object  10 ′. Unlike conventional canoes and kayaks, in which portions of the occupants&#39; bodies are below the water line, object  10 ′ lacks any recess in which an occupant may sit. Instead, upper surface  62  of object  10 ′ is flat (or at least substantially so), so that an occupant sits on upper surface  62 —above the water line rather than below it. 
     Object  10 ′ may include backrest  66  or a similar component if desired. Backrest  66 , as depicted in FIG. 4, additionally may be attached to and protrude upward from upper surface  62  so as to contact the back of a seated occupant of object  10 ′. FIG. 4 illustrates a system for attaching an exemplary backrest  66  in which fasteners  70  connect with D-rings or other tie-downs  74  extending from upper surface  62 . Clear to those skilled in the art is that such a system permits backrest  66  to be detached and removed from upper surface  62  when appropriate or desired. Equally clear, moreover, is that backrest  66  may be connected to upper surface  62  in manners other than shown in FIG.  4 . 
     Some embodiments of object  10 ′ optionally include, on upper surface  62 , one or more foot rests  78  or handles  82 , cargo net  86 , valve assemblies  90 , and zipper  94 . Foot rests  78 , if present, typically are spaced from backrest  66  a distance approximately equal to the length of the legs of an average user of object  10 ′. They preferably are attached to upper surface  62  using material  22 ′, although other attachment materials may be used instead. Although two valve assemblies  90  are shown in FIG. 4, permitting separate inflation of portions of chambers  14 ′, more or fewer such assemblies  90  may be employed. Assemblies  90  optionally may include flaps  98  covering the valves themselves. Zipper  94 , finally, permits removal of chambers  14 ′ when opened. 
     Detailed in FIG. 5 is object  10 ″, similar to object  10 ′ except that it admits simultaneous use by two occupants. Indeed, object  10 ″ may include two backrests  66  and two sets of foot rests  78 , one for each of the two occupants. Object  10 ″ otherwise may be configured substantially like object  10 ′ and thus will not be discussed in any greater detail in this application. 
     The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.