Abstract:
A folding kayak includes fore and aft subassemblies which are joined together and are covered by a water-impermeable skin to provide a watercraft with the favorable attributes both hard shell and skin on frame kayaks, with none of the disadvantages. In addition, one or more hydraulic adjustment mechanisms provide the kayak with characteristics of a plurality of different rigid body kayaks, with different operational characteristics, suitable for open-ocean or closed-water environments as desired. Ribs which are part of the kayak assembly have a relatively flat profile, making the kayak perform more favorably in adverse water conditions, and also giving the kayak some resilience and flexibility when encountering obstructions in the water. In one aspect, the kayak subassemblies may be joined, at least in part, by corrugated splines. By rotating these corrugated splines within elongate tubes that form part of the respective subassemblies, it is possible to remove crystalline, corrosive, and other build-up. The kayak may be disassembled into a relatively compact, easily transportable package.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application claims priority from United States Provisional Application No. 60/821,699, filed Aug. 7, 2006. The contents of that provisional application are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a collapsible boat, such as a kayak, in which a skin or shell of water impermeable material covers an internal framework of rigid members. The rigid members are configured for ease of assembly of the boat.  
       BACKGROUND OF THE INVENTION  
       [0003]     The present inventor is a named inventor on two other patents which describe prior approaches to provision of a collapsing or foldable boat. Those patents are U.S. Pat. No. 5,875,731 and U.S. Pat. No. 6,371,042. Those prior approaches had several disadvantages, making the boat more difficult to assemble and operate.  
       SUMMARY OF THE INVENTION  
       [0004]     In one aspect, the invention provides a collapsible boat which has fore and aft hull assemblies which can be joined together by one or more adjustment mechanisms, those mechanisms facilitating adjustment of the boat&#39;s keel, thereby allowing the boat to sit differently in the water, and promoting either greater turning ability or greater lateral stability, depending on the degree of curvature of the keel. Those mechanisms also facilitate adjustment of the port or starboard gunwale, thereby aiding the user to steer in different kinds of cross currents. In a particular aspect, the adjustment mechanism herein provides advantages compared to the adjustment mechanisms that the above-referenced US patents describe.  
         [0005]     The inventive kayak includes a water impermeable skin which in one embodiment is a urethane (such as polyurethane) with a mesh framework which can be nylon or Kevlar, or other flexible material with satisfactory tensile strength characteristics. In one embodiment, the skin may be heat treated to promote a predetermined shape upon assembly. The skin has favorable memory characteristics, meaning that if the skin is stretched, for example, to provide greater keel curvature, when the frame is retracted, the skin will return to its original shape and size. By being heat treated (using a process known as thermoforming), the altered shape of the mesh framework can be held, upon cooling, to the desired predetermined shape.  
         [0006]     In one embodiment, the inventive kayak also has an adjustable seat whose position within the kayak can be adjusted to accommodate users of different heights.  
         [0007]     In accordance with another aspect of the invention, to make assembly easier, respective fore and aft gunwale, chine, keel, and deck portions are elongate tubes which fit into a bow assembly and a stern assembly, respectively, to form fore and aft subassemblies which then are placed easily into the fore and aft ends of the water impermeable skin. Ribs are positioned appropriately in those fore and aft subassemblies. The overall kayak kit thus has a minimal number of pieces for the user to put together, thus facilitating assembly.  
         [0008]     With the foregoing aspects, the assembled kayak will have the favorable characteristics of a rigid-body kayak (or actually, of a plurality of different rigid body kayaks), while at the same time being disassembled into a relatively compact, easily transportable package. The improved adjustability of the kayak enables the user effectively to possess a number of different kayaks with different operational characteristics, suitable for open-ocean or closed-water environments as desired. The resulting craft has all of the advantages of both hard shell and skin on frame kayaks, with none of the disadvantages.  
         [0009]     The inventive kayak accommodates a wide range of water and wind conditions, which can change constantly. At the same time, the kayak accommodates the varied skill levels of kayakers. The inventive kayak provides substantially instantaneous, on-demand, customized control of the hull shape, right from the cockpit. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Various aspects of the invention now will be described in detail with reference to the accompanying drawings, in which:  
         [0011]      FIG. 1  is a perspective view of one embodiment of a folding kayak in accordance with the invention.  
         [0012]      FIGS. 2A and 2B  are exploded view of an adjustment mechanism in accordance with embodiments of the invention.  
         [0013]     FIGS.  3 A-D are views of ribs which form part of the assembled kayak in accordance with one embodiment of the invention.  
         [0014]      FIG. 4  is a cross-sectional view of one embodiment of a spline for connecting portions of the inventive kayak.  
         [0015]      FIG. 5A  is a perspective view of a coaming, and  FIG. 5B  is a perspective view of a pillar that fits with the coaming in the cockpit of the kayak.  
         [0016]      FIG. 6  is a cross-sectional view of a keder assembly. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0017]      FIG. 1  shows the overall frame assembly  100  for the inventive folding kayak. A forward keel portion  110  and aft keel portion  112  are shown. In one embodiment, these two pieces are joined, as are other pieces of the kayak as will be described, via an hydraulic jack assembly  200 ,  200 ′ ( FIGS. 2A and 2B ).  
         [0018]     Forward and aft chine portions  120 ,  122 , are provided on the port and starboard sides of the kayak. The fore and aft chine portions on each side are joined by respective central chine portions  121 . Forward and aft gunwale portions  130 ,  132  also are provided on the port and starboard sides of the kayak. In one embodiment, one or more of these sets of forward and aft gunwale portions are joined by an hydraulic jack  200 ,  200 ′. Where a jack assembly  200 ,  200 ′ is not provided, central gunwale or keel portions may be substituted, similarly to the central chine portions  121 .  
         [0019]     The fore and aft keel portions  110 ,  112  (with a jack  200 ,  200 ′); chine portions  120 ,  121 ,  122 ; and gunwale portions  130 ,  132  (with a jack  200 ,  200 ′) may be joined by respective splines  290 . A cross-section of a spline  290  is shown in  FIG. 4 . Each spline  290  is sufficiently elongate, and appropriately dimensioned to fit snugly within the diameter of the chine, keel, and gunwale portions, and also to provide a snug fit of the jack assemblies with the keel and gunwale portions. The splines  290  are corrugated, as shown. One advantage of the corrugation is a facilitated snug fit. Another advantage, particularly in corrosive or deposit-building environments such as encountered in salt-water kayaking, is that rotation of the corrugated splines within their respective chine, keel, or gunwale portions will aid in removal of corrosion or build-up, without the need for repeated lubrication or other maintenance.  
         [0020]     The kayak is covered with a skin  102  (shown in a sort of sectional view as a partially transparent triangular shape in part toward the stern portion of the kayak) which in one embodiment may be polyurethane with a mesh weave such as nylon or Kevlar™. The skin should be durable and resilient, but should have relatively little memory, so that when it is stretched for purposes of adjusting the keel or one or more gunwales, the material will not remain in its stretched position, but rather will return to its original configuration or shape. In one embodiment, the skin  102  may be heat treated, using a process known as thermoforming, so that the configuration of the mesh is altered slightly, to conform to the shape of the frame when the frame is inserted into the kayak. However, thermoforming is not critical to the assembly and operation of the kayak.  
         [0021]     As also shown in  FIG. 1 , there are fore and aft deck portions  140 ,  142 . One or both of these deck portions, as well as the gunwale portions  130 ,  132 , the chine portions  120 ,  122 , and keel portions  110 ,  112 , may be made of a suitable lightweight, strong material, such as aluminum or magnesium, including but not limited to (in one embodiment) aerospace grade anodized aluminum. Selection of appropriate gauge for this tubular material, among other physical characteristics, will be known to those skilled in the art. Where appropriate, it may be possible to use graphite or other similar material for these portions. Materials which are not overly brittle, and which are sufficiently impact resistant to withstand damage under the kind of conditions that kayakers can experience, will be particularly suitable.  
         [0022]     One or more access hatches  152 ,  154  may be provided, to provide access to fore or aft portions inside the kayak, thus enabling the user to access storage areas to store gear.  
         [0023]      FIG. 1  also shows a bow assembly  160  and bow assembly connector  162 . In one embodiment, to facilitate assembly, the bow assembly  160  and bow assembly connector  162  may be connected to the forward portions of the gunwale, chine, and keel, providing a single unit which the user can assemble by connecting ribs  300 ,  320  ( FIGS. 3A and 3B ), as will be discussed.  FIG. 1  further shows a stem assembly  170  and stem assembly connector  172 . In one embodiment, to facilitate assembly, the stem assembly  170  and stem assembly connector  172  may be connected to the aft portions of the gunwale, chine, and keel, providing a single unit which the user can assemble by connecting ribs  340 ,  360  ( FIGS. 3C and 3D ), as also will be discussed.  
         [0024]     As noted above,  FIG. 1  shows ribs  300 ,  320 ,  340 , and  360  ( FIGS. 3A-3D ). These ribs are joined to the fore and aft assembly portions as part of the overall assembly of the kayak. To facilitate assembly, the ribs may have openings which mate with corresponding protrusions in the respective, appropriate fore and aft gunwale, chine, and keel portions. Alternatively, as would be known to those skilled in the art, the ribs may have respective protrusions which mate with holes in the respective fore and aft portions of the deck portions, gunwales, chines, and keel. As a still further alternative, as will be discussed below with respect to  FIGS. 3A-3D , the ribs may be formed with appropriate openings into which the deck, gunwale, chine, and keel portions may be forced or press fit. In one aspect, the ribs may include a ball stud receiver piece, provided as an insert in the ribs, and allowing for tuning the resistance for inserting and removing ball stud connectors during kayak assembly and disassembly. As yet a further alternative, the ribs may be formed with openings that are more closed-ended than is shown in  FIGS. 3A-3D , so that the deck, gunwale, chine, and keel portions may be inserted through those openings. The openings may be completely closed, or partly open. Other ways of mating the ribs to the fore and aft gunwale, chine, and keel portions will be apparent to those skilled in the art, so as to mate the ribs to the rest of the assembly, and thus add rigidity to the overall kayak.  
         [0025]     While various rib attachment approaches may be apparent to the ordinarily skilled artisan, an important consideration is the ability to assemble and disassemble the kayak without fatiguing the attachment means on either the rib or the deck, gunwale, chine, or keel portions. As the ribs may be made, for example, of a rigid plastic material, it appears that having openings in the ribs, rather than protrusions, may make the assembly most resistant to fatiguing or wearing out of the parts that have to be attached to each other. Providing metal protrusions on the deck, gunwale, chine, and keel portions would be suitable.  
         [0026]     One aspect of the ribs shown in  FIGS. 3A-3D  is that, as shown, the ribs have a relatively flat profile, and thus are more flexible than ribs used in conventional kayaks. Previous approaches to forming these ribs have emphasized stiffness over resilience. As a result, the ribs have been thicker in profile.  
         [0027]     The ribs shown in  FIGS. 3A-3D  have at least two advantages. First, their lower profile makes it easier to store gear fore and aft, because it is not necessary to slide gear over relatively tall impediments. Second, while the profile shown provides favorable stiffness characteristics, this profile also provides resilience to cope with aggressive wave conditions, and also to cope better with obstructions that a kayaker can encounter. Flexing and conforming with waves, rather than plowing through them, provides more favorable performance. Running into rocks and the like can cause varying degrees of damage, but the greater resilience of the overall assembly of the inventive kayak makes the kayak more resistant to damage.  
         [0028]      FIG. 1  also shows a seat  190  with a pillar  192  and a seat adjustment portion  194 . The seat  190 , pillars  192 , and seat adjustment portions  194  are positioned within coaming  180 , which fits as part of the overall kayak  100 . Coaming  180  (shown in more detail in  FIG. 5A ) defines part of a cockpit in the kayak. The seat  190  may be positioned in various locations within the kayak  100  to accommodate different user heights.  
         [0029]      FIG. 5B  shows a pillar  192  and seat adjustment portion  194  in more detail. Pillars  192  (one on each side of the kayak)) mate with respective receiving portions  196  in coaming  180  ( FIG. 5A ). Seat  190  locks in place simply by sliding it back and snapping it down on seat adjustment portions  194 , and unlocks by lifting up on the seat to release it from portions  194 . Receiving portions  196  in coaming  180  may be adjustable locking sliders which can be moved forward and backward, thereby defining locations of pillars  192 , and then bolted in place. In another embodiment, the seat may have pegs which fit into differently-placed holes in pillars  192 . Depending on the hole that the user selects, the seat may be positioned more forwardly in the cockpit, or farther back. As one alternative, the seat may have holes which mate with one of a set of pegs in pillars  192 . As further alternatives, the plurality of holes or pegs may be placed on either side of seat  190 , to mate with corresponding pegs or holes in pillars  192 . Other attachment and adjustment alternatives will be apparent to those skilled in the art.  
         [0030]      FIGS. 2A and 2B  show exploded views of embodiment of a jack  200 ,  200 ′, in which like elements have the same numbering. Anywhere from one to three such jacks may be provided as part of the overall kayak. To adjust the keel, one such jack  200 ,  200 ′ may be placed in the bottom, to which the fore and aft keel portions  110 ,  112  are joined. Operation of the jack  200 ,  200 ′ will drive the fore and aft keel portions away from each other, causing the ends of the kayak to turn upwardly and adjusting the rocker of the kayak.  
         [0031]     To help the user compensate for differing cross-current and cross-wind conditions, additional jacks  200 ,  200 ′ may be provided on the left and/or right hand side of the overall assembly, joining the respective fore and aft gunwale portions  130 ,  132 . By actuating a jack on the port or starboard side of the kayak, it is possible to alter the yaw of the boat. In this manner, it is possible to alter the length and arc of the kayak. As a result, a rudder, or skeg, is not necessary.  
         [0032]     In one embodiment, the jack  200 ,  200 ′ is an hydraulic jack with a handle  202 , housing  216 , reservoir tube  218 , and ram tube  226 , among other parts, as will be discussed in greater detail with respect to  FIGS. 2A and 2B . When the handle  202  is operated, ram tube  226  extends, pushing apart the fore and aft portions of the members which the jack mates. Thus, to adjust the rocker on the kayak, the fore and aft keel portions  110 ,  112  may be pushed apart, thereby causing greater curvature in the keel. As a result of the curvature of the keel, the fore and aft portions of the kayak extend upwardly away from the water. When the jack is released, the portions return to their normal configuration and alignment. The skin  101  returns to its original shape. To adjust the yaw on the kayak, the fore and aft gunwale portions  130 ,  132  on either the port or starboard sides may be pushed apart, thus changing the length and arc of the kayak.  
         [0033]     Looking at one embodiment of jack  200 ,  200 ′ in  FIGS. 2A and 2B  in more detail, handle  202  has handle tube  204  attached to it, and a handle end  206  attached to the end of that, for ease of gripping and operation. Handle pins  210  attach handle links  208  to housing  216 . Piston pin  214  attaches piston  212  to handle  202 . Piston  212  in turn fits into housing  216 . Pump action of handle  202  causes piston  212  to move in and out of housing  216 .  
         [0034]     Reservoir tube  218  fits into one end of housing  216 , and ram tube  226  fits into the other end of housing  216 . Reservoir spring  220  fits into reservoir tube  218 , and presses against reservoir piston  222  which fits within reservoir tube  218 . Reservoir shoulder  224  closes off one end of reservoir tube  218 , and is secured to reservoir tube  218  with ball stud  244 .  
         [0035]     Ram  228  fits into ram tube  226 , and also has a smaller diameter than reservoir tube  218  as shown, so as to fit into reservoir tube  218 . A ram shoulder  230  is secured at the end of ram tube  226  by D-link  242  ( FIG. 2A ) or by screw  246  ( FIG. 2B ).  
         [0036]     Various O-rings (shown in the Figures, but unnumbered) seal the various portions of the reservoir tube  218  and ram tube  226  within housing  216 . Check valves  232  and  234  serve to hold the jack  200  in an extended position when the user operates the handle  202 . In  FIG. 2A , ball valve  236  cooperates with pin-valve handles  240  to actuate the ram. Other ram actuation mechanisms for either the  FIG. 2A  or  FIG. 2B  embodiment will be apparent to ordinarily skilled artisans, and so need not be detailed here.  
         [0037]     When one of the jacks that mates the fore and aft gunwale portions on either the port or starboard sides is operated, that side of the kayak will be extended, thus affecting the turning capabilities of the kayak. When the jack is released, the fore and aft gunwale portions will then return to their original configuration and alignment, and the skin  101  will return to its original shape. Likewise, when one of the jacks that mates the fore and aft keel portions is operated, the curvature of the keel will change. The keel will be lengthened, thus causing the ends of the kayak to turn upwardly, thus changing the curvature of the keel. Again, when that jack is released, the fore and aft keel portions will return to their original position, and the skin  101  will return to its original shape.  
         [0038]      FIGS. 3A-3D  show the respective ribs  300 - 360 . In  FIG. 3A , forward rib  300  has a frame  301  and a plurality of indentations  302 , which mate with respective deck, chine, gunwale, and keel portions. In one embodiment, openings  304  accommodate corresponding protrusions on the deck, chine, gunwale, and keel portions in the forward part of the kayak assembly, to mate the rib to those portions. As known to ordinarily skilled artisans, the positions of the protrusions and openings may be reversed, so that the protrusions are provided on the rib rather than on the respective chine, gunwale, keel, and deck portions. As discussed, the overall goal is to provide ease of assembly and sturdiness and stability through repeated assembly and disassembly operations. Other attachment techniques will be apparent to those skilled in the art.  
         [0039]     Similarly to  FIG. 3A ,  FIG. 3B  shows a more central rib  320  with a plurality of indentations  322  and openings  324  around a frame  321 , for similar mating purposes with respective forward portions of the deck, chine, gunwale, and keel portions. In one embodiment, this rib  320  may be placed just forward of the coaming  180 .  
         [0040]      FIG. 3C  similarly shows a relatively central rib  340  with a plurality of indentations  342  and openings  344  around a frame  341 , this time to accommodate aft portions of the deck, chine, gunwale, and keel portions. Attachment may be achieved as in the same manner as with the ribs in  FIGS. 3A and 3B . In one embodiment, the rib  340  is positioned just behind the coaming  180  in the overall frame.  
         [0041]      FIG. 3D  shows a fourth, rearwardly positioned rib  360  with a plurality of indentations  362  and openings  364  around a frame  361 . This rib also accommodates appropriate portions of the deck, gunwale, chine, and keel, members. This rib is positioned between the coaming  180  and the stern assembly  170 .  
         [0042]     Various appropriate positions of the ribs  300 - 360  will be apparent to those of ordinary skill in the art, based on considerations of ease of assembly, strength, and rigidity of the overall frame. Materials for the ribs may be selected as appropriate, to provide necessary and appropriate torsional rigidity, also taking into account ease of fabrication.  FIGS. 3A-3D  show various openings in the ribs. These openings help to lighten the ribs without sacrificing significant strength. The openings likewise may be varied, as will be known to ordinarily skilled artisans.  
         [0043]     As another aspect of the invention, not shown specifically herein but described, for example, in  FIGS. 9-11  and col.  8 , lines  2 - 12  of U.S. Pat. No. 6,371,042, this portion being incorporated herein by reference, the skin  102  may have a central cockpit opening and one or more deck slits extending from the cockpit opening into the fore and aft sections of the kayak to allow for enlargement of the cockpit opening to permit the hull sections to be inserted into the skin  102 .  FIG. 1  shows a keder assembly  156  which may be used to close the deck slit. A cross-section of keder assembly  156  is shown in  FIG. 6 . The sides of the deck slit may have a keder (a cord or rope around which the material of skin  102  is wrapped, forming a protruding piece) which fits in keder assembly  156 ).  
         [0044]     While the inventive kayak has been described herein with reference to a number of embodiments, various modifications within the scope and spirit of the invention will be apparent to ordinarily skilled artisans. Therefore, the invention should be considered as limited only by the scope of the following claims.