Abstract:
Watercraft flooring including both inflatable and non-inflatable elements is detailed. Such flooring may be designed to support substantial loads while maintaining its lightweight nature and contributing to its longitudinal and lateral rigidity. Some versions of the flooring have an inflatable core with slats positioned both above the upper surface of the core and below the lower surface of the core at regular intervals along its length. The slats extend laterally across substantially the width of the core, effectively sandwiching portions of the core between them.

Description:
FIELD OF THE INVENTION 
     This invention relates to watercraft, particularly (although not exclusively) to inflatable watercraft, and to inflatable flooring therefor. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 5,868,095 to Zeromski, et al., incorporated herein in its entirety by this reference, details exemplary inflatable flooring for watercraft such as inflatable boats. Flooring described in the Zeromski patent is denoted as “rigid” and comprises “at least one watertight enclosed chamber of a generally very flat shape and which can be inflated to a relatively high pressure.” The chamber is defined (in part) by upper and lower main walls, with each wall being formed of
         at least one sheet of at least one flexible and airtight material. In general, each wall is constituted by an assembly of several sheets . . . which each have specific individual compositions and characteristics . . . . The two walls are also connected to each other by a multiplicity of flexible links such as threads, all of approximately the same length, anchored in [the] walls and holding them against the separating force generated by the inflation pressure.
 
See Zeromski, col 2, 11 29-47 (numerals omitted). Additionally addressed in the Zeromski patent are anti-slip materials for the external face of the upper wall.
       

     U.S. Pat. No. 6,164,237 to Coryell, et al., also incorporated herein in its entirety by this reference, illustrates an inflatable one-man raft with an inflatable “half-floor . . . formed generally at the forward end.” The rear end of the raft, by contrast, “is open in a vertical direction to permit the operator&#39;s legs to extend downwardly into the water.” See Coryell, col. 2, 11 17-20. According to the Coryell patent:
         The half-floor may comprise a plurality of transverse tube sections mounted in edge-to-edge relationship. The transverse tube sections may be mounted to the main floatation member so that the series of transverse tubes generally follow an inclined plane which slopes upwardly towards the rearward end of the craft.
 
See id., 11. 27-33. Because it is designed to function as the operator&#39;s seat rather than as a floor per se, the half-floor of the Coryell patent additionally may include “a generally upright back rest.” See id., 1. 43.
       

     Unlike those of the Zeromski patent, many inflatable floors (presumably including the “half-floor” of the Coryell patent) are not sufficiently strong to support significant numbers of persons and equipment, as might be necessary to transport combat troops and military gear, for example. Such floors, although very light and compact when folded, can be punctured relatively easily, reducing their strength and the performance of their corresponding boats. As a consequence, some inflatable (and other) boats utilize rigid, non-inflatable floors. These rigid floors often are made of multiple sections that can be removed from the boat and stacked for packing. Because they are sectioned, however, they must be installed (or reinstalled) following inflation of the boat, slowing deployment. 
     Yet other flooring presently in use encompasses rigid, foldable (“roll-up”) floors. These types of floors, which are not inflated, are typically made of aluminum or wooden slats. To counteract deficiencies in strength and lateral rigidity, the slats are often oversized, resulting in a floor that is heavier and larger than analogous inflatable floors. Further, such roll-up floors frequently are wavy, exhibiting poor longitudinal rigidity in use 
     SUMMARY OF THE INVENTION 
     The present invention provides alternate flooring including both inflatable and non-inflatable elements. Utilizing an inflatable core permits the flooring to support substantial loads while maintaining its lightweight nature. Such a high-pressure inflatable core additionally contributes to longitudinal and lateral rigidity of the flooring, avoiding diminished stability associated with some existing floors. 
     By contrast, including non-inflatable slats in the flooring prevents cambering of the inflatable core and helps protect the core from punctures even when the flooring is subjected to substantial forces. Moreover, even if the core is punctured or otherwise deflates wholly or partially, the non-inflatable slats will provide some residual rigidity, at times adequate to permit accomplishment of the then-current mission. Finally, because normally rigidity is principally provided by the inflatable core, the slats need not be oversize or as numerous as in existing slatted floors. They likewise may be hollow if desired, reducing their overall weight and facilitating roll-up for storage. 
     Some preferred embodiments of the invention include an inflatable core spanning much or all of the distance between side buoyancy tubes of an inflatable watercraft. Positioned above the upper surface of the core and below the lower surface of the core at regular intervals along its length are hollow slats. These slats extend laterally across substantially the width of the core, effectively sandwiching portions of the core between them. Stringers comprised of brackets and straps additionally may be used to connect pairs of corresponding upper and lower slats. Such brackets preferably (although not necessarily) are formed of aluminum and may be angled to match generally the angles existing between the fabric bottoms and the side buoyancy tubes of certain inflatable boats. 
     Alternatively, the upper and lower slats may be connected by rigid material or otherwise formed so as to retain their vertical spacing even if the inflatable core deflates. Furthermore, because the slats themselves typically are rigid, accessories (e.g. seats, steering consoles, storage boxes, etc.) may be bolted, directly or indirectly, to them. This avoids required use of the “D”-rings or straps often glued or welded to current inflatable components, although such rings and straps may continue to be used if desired. Finally, the inflatable cores may be designed and sealed so as to provide through holes or passages facilitating access to the bilge area underneath the floor. These holes or passages also allow for hoses, pipes, or other devices to pass through the core without deflating it 
     It thus is an optional, non-exclusive object of the present invention to provide innovative flooring for watercraft. 
     It is an additional optional, non-exclusive object of the present invention to provide flooring comprising both inflatable and non-inflatable elements. 
     It is also an optional, non-exclusive object of the present invention to provide lightweight flooring for inflatable watercraft that is designed both to reduce vulnerability to punctures and to enhance its rigidity and stability. 
     It is another optional, non-exclusive object of the present invention to provide for watercraft a removable floor comprised of an inflatable core and spaced sets of non-inflated slats. 
     It is, moreover, an optional, non-exclusive object of the present invention to provide flooring including brackets shaped generally to match angles existing between bottoms and interior sides of watercraft. 
     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 a perspective view of exemplary flooring of the present invention shown in an inflated state. 
         FIG. 2  is a cross-sectional view of the flooring of  FIG. 1  illustrating its installation in an inflatable boat. 
         FIG. 3  is a cross-sectional view of the installed flooring of  FIG. 2  illustrated in a deflated state. 
         FIG. 4  is a side view of the type of flooring of  FIG. 1  shown in a deflated state and rolled-up (as, for example, for storage). 
         FIG. 5  is a perspective view of an exemplary stringer adapted for use with or as part of the present invention. 
         FIGS. 6A-B  are cross-sectional views of the stringer of FIG.  5 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  illustrate exemplary flooring  10  of the present invention. As detailed therein, flooring  10  may comprise core  14 , lateral components  18  (comprising sets of upper and lower slats  22  and  26 , respectively), and stringers  30 . Although  FIG. 1  illustrates five such components  18  and  FIG. 4  illustrates six, those skilled in the art will recognize that more or fewer such components  18  may be utilized as part of any particular flooring  10 . Likewise, although not presently preferred by the applicants, various of upper or lower slats  22  or  26  of the sets, or some or all of stringers  30 , may be omitted if desired. 
     Core  14  preferably is inflatable with air or other gas. Using such a core  14  provides a lightweight way of providing flooring that may support substantial loads. Indeed, embodiments of core  14  may be designed to be inflated to relatively high pressures (on the order of one bar) for use in supporting quantities of troops and equipment being transported over water. Because so inflated, core  14  also may contribute to longitudinal and lateral rigidity of flooring  10 . 
     Typically characterized as being rigid when inflated, core  14  may, for example, be made consistent with the description in the Zeromski patent, hence including upper and lower walls  34  and  38  and multiple flexible links  42  therebetween. Core  14  may, however, be formed differently than as described in the Zeromski patent. Regardless, core  14  preferably includes one or more watertight, inflatable chambers and valves or other mechanisms allowing their inflation. 
       FIG. 2  details flooring  10  as installed in an exemplary watercraft W for use. Watercraft W, depicted as of the inflatable type, includes side buoyancy tubes  46  and  50  of a generally “U”-shaped buoyancy unit defining a hull. Also shown in  FIG. 2  are keel  54  and base  58  of watercraft W. Typically (although not necessarily) made of waterproof fabric, base  58  is intended to span the distance between tubes  46  and  50  and to attach thereto. Consistent with the inflatable boat of the Zeromski patent, keel  54  may itself comprise an inflatable tube positioned centrally within watercraft W intermediate flooring  10  and base  58 . As a consequence, base  58  normally assumes a generally “V”-shape when in use. Again, however, either or both of keel  54  and base  58  may differ from the preferred components shown in  FIG. 2  or be omitted if appropriate or desired. 
     Spaced along the length of core  14  are sets of upper and lower slats  22  and  26 , with upper slats  22  abutting upper wall  34  and lower slats  26  abutting lower wall  38 . In regions adjacent tubes  46  and  50 , stringers  30  may be used to connect sets of the upper and lower slats  22  and  26  so that, when core  14  is inflated, tension exists in flooring  10 . Doing so may maintain or enhance both the rigidity and the stability of the flooring  10 . 
     Any desired spacing may be used between sets of upper and lower slats  22  and  26 . Preferably, the spacing will be uniform (or approximately so) between adjacent sets of slats  22  and  26 . Alternatively, the spacing may be non-uniform, or selected slats  22  or  26  may be omitted from any particular set. Nevertheless, slats  22  and  26  typically need not be oversized (because of the general rigidity provided by inflated core  14 ) and need not be as numerous as in existing slatted floors 
     Each of slats  22  and  26  may be made of metal (advantageously non-corrosive metal), wood, plastic, glass-reinforced polyester, or a composite or laminated material such as (but not necessarily) polyurethane, polyethylene, or other rotomolded materials. Preferably, however, upper and lower slats  22  and  26  are made of aluminum formed into hollow planks. Utilizing hollow aluminum slats permits formation of relatively flat footing surfaces for troops and cargo and provides substantial strength while being lightweight itself. The presence of slats  22  and  26  additionally reduces the likelihood of core  14  being punctured (and inflation consequently lost) should, for example, heavy or sharp objects be thrown into watercraft W, and inhibits core  14  from cambering. 
     Further, even if core  14  becomes deflated in use, the existence of slats  22  and  26  provides residual rigidity, which in some cases may be adequate to facilitate accomplishment of the then-current mission of watercraft W before the core  14  need be repaired and reinflated. Absent use of slats  22  and  26 , by contrast, deflation of core  14  could significantly adversely affect the longitudinal and lateral rigidity of watercraft W itself Because watercraft W may be used with powerful outboard engines, this decrease in rigidity could in turn substantially impact proper performance of the boat, especially at high speed. 
       FIG. 3  illustrates flooring  10  with core  14  in a (fully) deflated condition while within watercraft  10 . Notwithstanding this condition, the periphery of core  14  remains surrounded by lateral components  18  and stringers  30 , as the force of gravity (and weight of troops or objects in watercraft W) directs upper slats  22  downward (in the direction of arrow A). Components  18  and stringers  30  thus help maintain proper positioning of core  14  within the watercraft W even when the core  14  is deflated. 
     Deflating core  14  also facilitates removal of flooring  10  from watercraft W for storage, repair, or otherwise. Depicted in  FIG. 4  is such flooring  10  rolled-up for movement apart from watercraft W or for storage. The slim profile and lack of oversizedness of slats  22  and  26  additionally facilitate rolling flooring  10  in the compact fashion illustrated in FIG.  4 . 
     FIGS.  5  and  6 A-B present selected views of stringers  30 . Each stringer  30  preferably comprises bracket  62  and strap  66 , with the latter typically connected at least to an upper slat  22 .  FIG. 3  further details the possibility of bracket  62  including (optional) notch  70  to receive lower slat  26 . Regardless, however, the combination of two stringers  30  and a set of upper and lower slats  22  and  26 , as depicted in  FIG. 3 , will completely surround the periphery of a portion of core  14 . 
     One acceptable material for forming bracket  62  is aluminum, while strap  66  preferably is fabric. Bracket  62  may be shaped (as shown especially in  FIGS. 6A-B ) to fit the angle made by the attachment of base  58  to either of tube  26  or  30 . Doing so increases the ability of flooring  10  to span substantially the entire distance between tubes  26  and  30 , as brackets  62  need not protrude significantly from tubes  26  and  30 . Those skilled in the art will, however, recognize that stringers  30 , if present, need not necessarily be constructed as illustrated in  FIGS. 2 ,  5 , or  6 A-B. 
     The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits 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. As non-limiting examples of some of such adaptations, flooring of the present invention additionally may include such features as an anti-slip composition as disclosed in the Zeromski patents or a protective coating or composition for core  14  designed to increase its resistance to punctures. Indeed, in some embodiments of flooring  10 , such a puncture-resisting coating or composition could replace some or all of lateral components  18  and stringers  30 .