Abstract:
A self-loading and unloading trailer which can be operated by a single person to load a boat from difficult boat ramps or even directly from the ground provides rollers for engaging a boat. A first set of rollers engages the boat at ground level, enabling the boat to be winched directly from the ground or from a shallow landing. As the boat is loaded, the rollers shift and transfer the load directly to a second set of rollers. Finally, the boat weight shifts the trailer again, causing the rollers to retract, thereby bringing the boat to safely rest on bunks for storage or during transit. In the preferred embodiment, the boat is a pontoon boat, though other appropriate boat hulls are contemplated for use with the present invention.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional patent application serial No. 60/297,331 filed Jun. 11, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains generally to land vehicles, and more particularly to wheeled, articulated vehicles constructed to accommodate a boat for transport. In an even more particular manifestation, the invention pertains to self-loading pontoon boat trailers. 
     2. Description of the Related Art 
     Boats of all sorts and types, used variously for leisure, sport and commerce, are transported upon an equally diverse collection of trailers. Trailers offer a number of benefits over transporting a boat directly upon an automobile, sport utility vehicle, pick-up truck, flat-bed truck, or the like. Among these benefits are loading and unloading the boat at an elevation closer to the ground; the ability to unload the boat directly into a waterway and reload the boat therefrom while still maintaining vehicle drive wheels upon dry ground for good traction; ready storage by simply unhitching the trailer from the vehicle, with associated rapid and simple retrieval from storage; and the ability to load and transport boats much longer than the motor vehicle. Since in some instances the boats are loaded or unloaded on a daily basis, these trailers most preferably simplify the loading and unloading process. 
     One of the more common techniques for supporting a boat upon a trailer uses rollers, which assist a person greatly with the loading and unloading of the boat. A hand or powered winch may be provided which draws the boat onto and across the rollers. Since the rollers are able to roll across the exterior of the boat, such as along the keel or along the port or starboard undersides, there is almost no scraping or sliding of the boat which would otherwise damage the boat, and there is very little force required to move the boat over the rollers. Consequently, a winch and cable may be hand-turned in many instances, and such winch and cable are generally relatively low cost commodity items. 
     While the rollers tend to simplify the loading and unloading of a boat, they do not provide good support for the boat. This is because the rollers normally have very little surface area in contact with the boat hull. At the point of contact, the forces placed upon the boat bull by the total weight of the boat and contents may cause the boat hull to deform. Even absent noticeable deformation, the stresses generated adjacent a roller tend to be very high, leading to premature failure of the boat hull. While additional contact may be obtained with the use of more rollers, which would thereby reduce the stress between the boat and any given roller, rollers tend to be relatively expensive. Consequently, supporting more than a very minor amount of surface area on the boat with rollers is cost prohibitive. 
     In contrast, another common technique for supporting a boat upon a trailer uses bunks, which are solid surfaces against which a boat hull is rested. In the case of a bunk trailer, the boat hull is solidly supported across the entire bunk, rather than across a few square inches of roller. Since the bunk is very low-cost, typically comprising little more than a beam having a non-marring surface, the cost of supporting a large surface area is quite small. This in turn leads to much better transport, including a substantial reduction in the stress forces generated within the boat hull and a resultant reduction in the likelihood for damage to the boat during transport. Unfortunately, this type of trailer creates much greater friction between the bunk and boat during loading and unloading, thereby necessitating a much more powerful winch. Additionally, should any foreign particles or devices or substances work their way between the boat hull and the bunk, these particles may cause substantial damage to the boat hull. 
     In some cases, prior art trailers are designed to accommodate several different types of boats with distinct hull designs. However, most trailers are designed for only one or a limited few types of boat hulls. For example, a trailer designed to carry a typical fishing boat will be shaped to accommodate the relatively deep keel and steeply sloping sides of the boat. In contrast, a shallow water boat or jon boat is designed with a relatively flat bottom. Consequently, a carrier designed to receive the keel and steep sides of a fishing boat will not receive and support a flat-bottom boat. The same holds true for other diverse types of boats, such as catamarans and pontoon boats, each which also have unique hull designs. These and other types of boats have consequently required specific trailer designs or accommodations. 
     In the specific case of a pontoon boat, the boat will generally include two or more pontoons, which are elongated tubes that may typically be sealed and hold air or another gas therein. Most commonly, across the top of the pontoons there will be attached a deck which supports passengers, a boat engine, and other various components, while simultaneously fixing the position of the pontoons relative to each other. 
     Pontoon boats have presented some challenges to trailer design that are relatively unique, for which desirable solutions have heretofore been elusive. Among these are the wide spacing of the pontoons. The pontoons, which are generally among the lowest components of a boat, are placed adjacent the edges of the deck in order to provide optimum floatation for passengers who may also be standing adjacent the deck edge. This spacing between pontoons makes for safer boating. Unfortunately, it also makes trailer design somewhat more difficult than with other types of boat hulls. This is because any support for a boat upon a trailer will most preferably be at the outer edges of the boat, so that as the trailer is turning a corner, for example, the boat is securely supported and does not tip over. Unfortunately, in the case of a pontoon boat and bunk trailer, support adjacent the outer edges of the boat also means raising the boat somewhat more off of the ground than would be required for a support more centrally located. Consequently, the elevated support may tend to be more difficult to load, and will typically require a relatively deep boat landing in order for the trailer to drop far enough for the pontoons to float off of the trailer. 
     Further limitation stems from the fact that unloading the boat from a prior art bunk trailer upon dry land is only practical if the operator has access to a small fork lift, skid steer or the like. The weight of a pontoon boat is measured in the thousands of pounds. The pontoons themselves, when resting upon the bunks, will not readily slide. Loading presents the same dilemma, since the pontoons will not slide along the earth. Consequently, an automobile will more readily slide along the ground than the pontoon boat. Winching the boat onto the trailer is therefore not practical. 
     To resolve these difficulties, another type of trailer has been designed specifically for pontoon boats, referred to in the prior art as a scissors-type trailer. Scissors trailers operate similar to a scissors jack, where the movement of a screw is used to separate or bring together two base elements. The spreading of these base elements will generally lower the trailer top, and a boat supported thereon, closer to the ground. Bringing the elements together will, through the scissors mechanism, raise the top of the trailer and the supported pontoon boat. With these scissors trailers, several distinct benefits and advantages are obtained in the transport of pontoon boats that are not available with bunk trailers. Most important to many pontoon boat owners is the ability to load and unload the pontoon boat in extremely shallow waters, or directly from the ground. Rephrased, the scissors trailer is designed to slip in the space between pontoons immediately under the deck, and then is used to jack the pontoons upward off of the ground or out of the water sufficiently to allow the boat to be transported safely. Unfortunately, since the trailer must first pass between the pontoons, the transverse distance across the trailer between wheels is significantly less than the width of the pontoons. Any significant elevation provided by the scissors trailer tends to make the trailer much more inclined to roll over, since the weight of the boat extends outside of the trailer wheels. Such roll-overs have the potential for causing great harm not only to the supported pontoon boat, but also to other persons and property which the boats would then collide with. 
     U.S. Pat. No. 5,292,145 by Ostrand, the contents which are incorporated herein in entirety by reference for the teachings of trailer and roller construction, illustrates a prior art trailer for a standard fishing boat or the like that supports a boat upon roller assemblies during loading and unloading and uses bunks for transport. In the Ostrand patent, an operator-activated motor-driven actuator retracts the rollers to allow the boat to rest upon bunks during transport. While the Ostrand patent may, at least in principal, appear to address one of the concerns of the prior art by combining bunks and rollers, this patent does not offer any benefit or advantage for loading and unloading adjacent the ground. Furthermore, two separate motive power devices are required to control this trailer. The first device is the winch, which is used to pull the boat onto the trailer. The second is the actuator, which is used to engage and disengage the rollers. There is no attempt to integrate these two separate functions into one, nor to assist with ground-level loading. Consequently, to load a boat with the Ostrand trailer, an operator must first back the trailer sufficiently under the boat to engage the rollers. Noteworthy here is the fact that, in practice, the level of the elevated rollers is the exact same level required for the boat to clear the bunks in the first place. In other words, during water launching and loading, the Ostrand rollers add no value to the trailer, since the operator will float the boat off of or onto the bunks. Since on dry land the boat must be raised to the elevation of the trailer, the rollers illustrated therein also add very little to a dry land loading and unloading. Consequently, the additional structure and expense offers very limited value in actual practice, while adding substantial cost and expense. Additional documents incorporated herein by reference for related teachings include U.S. Pat. No. 5,152,657 by Kehne; U.S. Pat. No. 5,133,571 by Urbank; U.S. Pat. No. 5,013,206 by Ernst et al; U.S. Pat. No. 5,004,260 by Smyly; and U.S. Pat. No. 3,768,677 by Moss, though none illustrate or teach the features and benefits of the present invention. 
     SUMMARY OF THE INVENTION 
     In a first manifestation, the invention is a boat trailer having support bunks which are active during boat transport for supporting a boat in combination with rollers that are moved during loading and unloading into an active position. The trailer includes a trailer bed with a ground-engaging wheel and a boat support frame having support bunks and rollers supported thereon. A pivot between the boat support frame and trailer bed allows the boat support frame to rotate relative to trailer bed. An actuator elevates the rollers relative to boat support frame responsive to a rotation between the boat support frame and trailer bed. 
     In a second manifestation, the invention is a method of loading a pontoon boat onto support blocks supported on a support frame of a trailer. The method includes the steps of pivoting the frame relative to the earth about a first axis in a first direction of revolution; moving a low-friction support to a first position of engagement with the pontoon boat, said first position of engagement occurring prior to a second position of engagement between support blocks and pontoon boat; engaging the low-friction support with pontoon boat; maintaining low-friction support in first position of engagement responsive to the engaging step; displacing the pontoon boat relative to the low-friction support subsequent to the engaging step to thereby redistribute forces applied to the frame; pivoting the frame in a second direction of revolution opposite to the first direction of revolution responsive to the redistributed forces; and moving the low-friction support from the first position of engagement to a third position of engagement occurring subsequent to the second position of engagement, whereby the pontoon boat is supported upon the support blocks. 
     In a third manifestation, the invention is in combination, a pontoon boat having a deck and a plurality of pontoons thereunder with a pontoon trailer. The pontoon trailer includes a wheel carriage; a pivot axis; and a support carriage adjacent the wheel carriage and pivotal relative thereto about the pivot axis. The support carriage has a plurality of bunks for carrying a pontoon boat during transport. An actuator is anchored to the support carriage at a first end and to the wheel carriage at a second end for producing an actuating movement responsive to a pivotal motion between wheel carriage and support carriage. A roller set is positioned relative to support carriage responsive to the actuating movement between a first position carrying the pontoon boat and a second transport position releasing the pontoon boat. 
     OBJECTS OF THE INVENTION 
     Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a self-loading and unloading trailer which can be operated by a single person to load a boat from difficult boat ramps or even directly from the ground. The trailer provides rollers for engaging the boat during loading and unloading of the boat, but safely rests the boat on bunks during transit. By incorporating the features of the present invention, the advantages of using a trailer for boat transport across land are preserved. These advantages include but are not limited to ready storage and rapid and simple retrieval from storage; and the ability to load and transport boats much longer than the motor vehicle. 
     A first object of the invention is to enable relatively safe loading, unloading, and transport of a pontoon boat using a trailer, and preserving the benefits attainable therewith. A second object of the invention is to load and unload a pontoon boat at ground level. Another object of the present invention is to unload a pontoon boat directly into a waterway and reload the boat therefrom while still maintaining vehicle drive wheels upon dry ground for good traction. A further object of the invention is to substantially reduce stress forces generated within the boat hull during loading, unloading and transport, to reduce the likelihood of damaging the boat during transport-related activities. Yet another object of the present invention is to alleviate damaging friction between bunk and boat during loading and unloading, while still obtaining the benefit of a bunk during transport. An additional object of the invention is to enable a single person to load, transport and unload a boat using the various embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 illustrates a preferred embodiment pontoon boat trailer constructed in accord with the teachings of the invention from top plan view. 
     FIG. 2 illustrates the preferred embodiment pontoon boat trailer from a side plan view in a transporting position. 
     FIG. 3 illustrates the most preferred pontoon boat trailer in an unloading position from a side plan view. 
     FIG. 4 illustrates a preferred release mechanism for securing and releasing the preferred embodiment pontoon boat trailer from or to transporting position from a projected, exploded view. 
     FIG. 5 illustrates a preferred roller mechanism for assisting with the release of a pontoon boat transported upon the preferred embodiment pontoon boat trailer, from an end plan view. 
     FIG. 6 illustrates the preferred roller mechanism of FIG. 5 from a side plan view. 
     FIG. 7 illustrates the preferred embodiment pontoon supports from an end plan view, illustrating the preferred adaptability. 
     FIG. 8 illustrates a preferred end stop from a projected view. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention is manifested in a most preferred embodiment of the invention illustrated in FIG.  1 . Therein, pontoon boat trailer  100  includes a standard coupling  110  for a ball-type hitch or the like. A tongue  111  extends therefrom, and has extending downwardly a jack or tongue support  112  upon which tongue  111  may be supported when coupling  110  is disconnected from a hitch. Onto tongue  111  is mounted a winch stand  120  having vertical support frame  121  and laterally extending frame brace  122 . While not illustrated for clarity of invention, a ladder, steps or similar structure may be provided along with winch stand  120  to permit safe access to a boat transported upon trailer  100 . Vertical frame  121  and frame brace  122  are most preferably slidably coupled to tongue  111  through sliding attachments  123 ,  124  respectively. The exact construction of sliding fasteners  123 ,  124  is not critical to the invention, and such fasteners as U-bolts, concentric tubing, bolts in slotted holes or other suitable adjustable methods of attachment to tongue  111  are contemplated herein. Distal to tongue  111  on vertical frame  121  is winch support  180 , coupled to vertical frame  121  through fastener  126 . Upon winch support  180  is winch  125 , which may be hand-cranked or which may alternatively be powered by other means, including but not limited to electric or hydraulic drives. Wrapped about a shaft or pulley on winch  125  is cable  127 , which will most preferably be a flaccid material of indeterminate length, sufficiently long in the most preferred embodiment to be used as a winch attached to a boat to be loaded upon pontoon boat trailer  100 . Cable  127  may be manufactured from various metals, metal alloys or polymeric materials, and will most preferably be resistant to moisture and fraying, while also providing ample tensile strength for the present embodiment. 
     Extending from tongue  111  are three carriage support braces  113 - 115  in the general arrangement of a crow&#39;s foot. The arrangement and construction of these carriage support braces is not critical, so long as sufficient strength and stability is provided for supporting an intended load, such as a pontoon boat, while providing additional safety margins. These carriage support braces  113 - 115  connect into a rectangular undercarriage having sides  102 ,  104 ,  106 , and  108 . Supporting undercarriage sides  102 - 108  are wheels  116 ,  117  suspended from undercarriage sides  102 ,  106  by suitable suspension components such as axle  119  and leaf springs  118  at opposite ends of axle  119 . 
     Pivotally supported from undercarriage sides  102 ,  106  is pontoon support upper frame  130 , having sides  131 ,  132  extending longitudinally parallel to tongue  111 , front end  141 , and back end  142 . Additional crossbars such as crossbar  143  may be provided, although crossbar  143  may alternatively be replaced by or alternatively encompass a pivot axle  148 . Axle  148  allows pontoon support upper frame  130  to rotate relative to undercarriage sides  102 ,  106  as is evidenced by FIG. 3, which illustrates pontoon support upper frame  130  rotated into a loading or unloading position. FIGS. 1 and 2 illustrate a transport or storage position, where pontoon support upper frame  130  extends in a plane generally parallel to undercarriage sides  102 - 108 . 
     Along a top of pontoon support upper frame  130  are a number of pontoon bunk-type support blocks  133 - 140 , which are designed to safely and securely support boat pontoons. The exact number arrangement of support blocks is not critical to the invention, and the geometries and counts will be determined in conjunction with the design of the boat to be transported. Advantageously, and as will be apparent, the present trailer provides no obstruction to the support of a triple pontoon, or other similar boat. 
     Support blocks  133 - 140  may be of any suitable materials, which in the preferred embodiment may have some frictional characteristics or may be specifically slippery, and may be slightly cushioning or compressible or rigid. These support blocks are most preferably sufficiently long to avoid damaging boat pontoons during transport over even the most rough of terrain. The width and thickness of support blocks  133 - 140  is again not critical, so long as support blocks  133 - 140  reasonably support boat pontoons and accommodate pontoons of slightly varying dimension. Contemplated materials include various treated lumbers, plastics or metals, whether coated or wrapped with secondary materials such as carpets or foams or left in the virgin or uncoated state. 
     In a contemplated embodiment, support sides  131 ,  132  of support frame  130  may be provided with slides, adjustments or other similar construction, whereby different boats maybe accommodated. As will be apparent, the addition of adjustable framework will not alter the basic function or operation of the invention, and will permit the embodiments to be used with a wider variety of watercraft. 
     Between undercarriage sides  102 - 108  and pontoon support upper frame  130  is adjustable roller frame  158 , which supports there on rollers  150 - 157 . Additional rollers  144 ,  145  are also fixedly attached to pontoon support upper frame  130  at the end distal to winch stand  120 . Each of rollers  152 - 156  are constructed as roller  151 , illustrated in FIGS. 5 and 6. A double-cone  160 , which may preferably be fabricated from a durable and preferably slippery material such as hard plastic or the like, is designed to roll between frame members  161 ,  162 , which are pivotally attached to pontoon support side  132  through pin  165 . Extending at an angle from frame members  161 ,  162  but rigidly attached thereto, are frame members  163 ,  164  which terminate at holes  166 ,  167 , which are designed to be pivotally attached through a pin or the like to roller frame  158 . While rollers are the preferred embodiment illustrated herein, other low-friction arrangements and designs as are known in the art are contemplated herein. 
     Rollers  144  and  150  act as a single unit, as do rollers  145 ,  157 . These rearward roller pairs are lowered adjacent support frame  130  during transport, but when tilted are raised therefrom. When raised, these rollers are designed to pivot at a point between. So, for example, rollers  144  and  150  will pivot such that when roller  144  raises, roller  150  lowers. This allows these roller pairs to follow the tilting of a pontoon boat as it climbs arms  190 ,  191  and then rolls forward onto the more forward rollers such as rollers  153 ,  154 . A single roller does not support the load as well, without risking damage to the pontoons. 
     Roller frame  158  is moved relative to pontoon support upper frame  130  in a longitudinal direction, parallel to tongue  111 , through an offset mechanism  177  shown in detail in FIG.  4 . Offset mechanism  177  includes a rod  171  having tabs  172 ,  173  pivotally attached thereto at opposite ends, that allow rod  171  to be rotated about an axis parallel to the longitudinal axis of rod  171 , while still following pontoon support upper frame  130  as frame  130  is raised or lowered adjacent winch stand  120 . Arm  174  extends from rod  171 , and is pivotally attached to roller frame  158 , and to arms  175 ,  176 , which are in turn pivotally attached through anchor  178  to tongue  111 . When in transport position, arms  174 - 176  extend longitudinally parallel to tongue  111 . However, upon release of latch key  179 , which may take the illustrated form or any of the multitude of alternatives known in the art, and raising of rod  171  to the loading or unloading position illustrated in FIG. 3, arms  174 - 176  extend vertically, thereby pulling roller frame  158  forward relative to pontoon support upper frame  130 . This movement of roller frame  158  relative to pontoon support upper frame  130  in turn causes frame members  161 - 164  to rotate about pin  165 , raising frame members  161 ,  162  to a position normal to the general plane of pontoon support upper frame  130  as well. In the most preferred embodiment, frame members  161 ,  162  are sufficiently long that this rotation to normal elevates double-cones  160  above support blocks  133 - 140 , in turn allowing a pontoon boat to be rolled off of blocks  133 - 140  on rollers  152 - 156 , across roller pairs  144 ,  150  and  145 ,  157 , across arms  191 ,  192  and onto any surface or into any body of water within reason, regardless of depth or elevation relative to wheels  116 ,  117 . 
     When the preferred embodiment pontoon boat trailer  100  is used to load a pontoon boat from the earth, additional advantage is obtained. As aforementioned, the pontoon boats tend to be very heavy, and they do not slide on the ground. Nevertheless, the pontoons do typically have tapered conical portions at the ends which cooperate with arms  190 ,  191  and rollers  192 - 196  during loading. A normal loading sequence will be to pivot support upper frame  130  about pivot axle  148 . This may be accomplished by attaching cable  137  to loop  170  and energizing winch  125 . When fully pivoted, wheel  198  will engage the ground, which prevents arms  190 ,  191  from digging into the ground at the end thereof distal to loop  170 . Next, pontoon boat trailer  100  will be backed up so that rollers  196 ,  197  engage with the front cones of the pontoon boat. The angle of arms  190 ,  191  will be adequate to create sufficient lifting force to pivot the pontoon boat relative to the earth. Furthermore, the friction between the boat and the earth will prevent any sliding therebetween. As pontoon boat trailer  100  is backed farther, the boat will continue to lift and ride progressively more upon support upper frame  130 . At some point of balance, and whether initialed by winch or additional backing of pontoon boat trailer  100 , the boat will shift forward onto rollers  151 - 156 , by first pivoting about roller pairs  144 ,  150  and  145 ,  157 . Finally, winch  125  through flaccid cable  127  will be used to pull the boat closer to winch  125 . Again, when the center of gravity of the boat passes across pivot axle  148 , support upper frame  130  will rotate back into a substantially parallel position with respect to undercarriage side  102 . In the most preferred embodiment, pivot axle  148  will be positioned such that the crossing of the boat center of gravity will bring the pontoon boat into proper position with respect to the bunks  133 - 140 , thereby setting the pontoon boat down onto the bunks without the need for further movement. Unloading onto the ground can be achieved by generally reversing the process, with the winch  125  raising support upper frame  130  to start the unloading. From there, the boat will be readily rolled off of trailer  100 , and trailer  100  will be driven out from under the pontoons once the pontoons touch the ground in at least one place. 
     As should now be apparent, the preferred embodiment pontoon boat trailer  100  offers advantages perhaps greater than the prior art scissors type trailers in terms of loading and unloading ease, while improving upon those trailers very substantially in terms of safe transport for both the trailer and boat. Likewise, preferred embodiment pontoon boat trailer  100  also offers safe transport equal to or better than prior art bunk-type trailers, while substantially improving upon those trailers for loading and unloading ease. While in the preferred embodiment rollers  144 ,  145 ,  150 - 157 , and  192 - 197  include double-cones  160 , it is understood that any low-friction surface may be provided, including a roller surface, bearings, or intrinsically slippery materials that may not rotate or move at all. 
     FIG. 7 illustrates the adjustable angle mounts  146 ,  147  that support blocks  139 ,  140 , to thereby accommodate different sizes of pontoons. FIG. 8 illustrates winch support  180  in greater detail, including boat stops  181 ,  182 , framework  184  and roller  183  across which cable  127  may pass. 
     As is by now apparent, trailer  100  may be manufactured from a variety of materials, including metals, resins and plastics, ceramics, or even combinations, composites or coated combinations of the above. The specific material used may vary. A variety of designs have been contemplated herein and will be apparent to those skilled in the pontoon trailer art. The materials used for a particular design may be chosen not only based upon factors such as weather resistance and weight, but may also factor in the particular design. Other variations are also contemplated herein with regard to alternative embodiments. Consequently, while the foregoing details what is felt to be the preferred and additional alternative embodiments of the invention, no material limitations to the scope of the claimed invention are intended. The possible variants that would be possible from a reading of the present disclosure are too many in number for individual listings herein, though they are understood to be included in the present invention. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated also.