Abstract:
The present system is directed in various embodiments to marine ladders comprising movement assistance for the transition from a deployed position to a stowed position and to assist in controlling the transition from the stowed position to the deployed position. In certain embodiments, the gas springs and associated pivot point brackets hold the deployed ladder biased in the deployed position with a biasing force that may be overcome by application of force by the user to initiate an automatic stowing process. The initial force to initiate the stowing process is provided by the force of water flowing against an aft-mounted ladder as a result of the boat moving forward. In the case of movement assistance from the stowed to deployed position, the user applies force to initiate the transition while the gas springs apply an opposing force that slows the transition for safety.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    None 
       FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to systems for marine boat ladders generally. More specifically, the present invention relates to systems enabling retractable marine boarding ladders. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    Generally, various embodiments of the present invention comprise an improved marine boarding ladder. As the skilled artisan will recognize, marine boarding ladders, e.g., swim ladders, and the like, are well known. 
         [0004]    However, the known marine ladders do not incorporate mechanisms to hold the ladder in the deployed position nor do they reduce the force required to raise the ladder into a stowed position or automatically retract the ladder into the stowed position. 
         [0005]    For example, some known ladders rotate at a point near the top of the ladder to stow or deploy. This requires application of force by the user throughout the process and may be quite awkward and difficult for some users. Some ladders also comprise a telescoping lower section that must be manually extended in order to achieve the deployed position and manually retracted. Still other ladders are permanently affixed to the boat. One feature all known non-permanent ladders have in common is that they all require a user to apply force throughout the processes of stowing and deployment sufficient to move the ladder into a stowed or deployed position. 
         [0006]    Thus, a need exists in the art generally for a marine ladder that provides movement assistance for the transition from a deployed position to a stowed position. A further need exists in the art for a deployed marine ladder that, following an initial application of force, automatically stows without further user intervention. 
         [0007]    The present invention addresses these, among other, needs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present system is directed in various embodiments to marine ladders comprising movement assistance for the transition from a deployed position to a stowed position and from the stowed position to the deployed position. In certain embodiments, the gas springs and associated pivot point brackets hold the deployed ladder biased in the deployed position with a biasing force that may be overcome by application of force by the user to initiate an automatic stowing process. Alternatively, and most preferably, the initial force to initiate the automatic stowing process is provided by the force of water flowing against an aft-mounted ladder as a result of the boat moving forward. The remainder of the force required to complete the automatic stowing process is provided by the gas springs. In the case of movement assistance from the stowed to deployed position, the user applies force to initiate the transition while the gas springs apply an opposing force that slows the transition for safety. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates perspective view of one embodiment of the present invention in a stowed position; 
           [0010]      FIG. 2  illustrates a cutaway perspective view of one embodiment of the present invention in the stowed position; 
           [0011]      FIG. 3  illustrates a side view of one embodiment of the present invention in the stowed position; 
           [0012]      FIG. 4  illustrates a perspective view of one embodiment of the present invention at a point in the transition from the stowed position to a deployed position; 
           [0013]      FIG. 5  illustrates a perspective view of one embodiment of the present invention at a point in the transition from the stowed position to the deployed position; 
           [0014]      FIG. 6  illustrates a perspective view of one embodiment of the present invention in the deployed position; 
           [0015]      FIG. 7  illustrates a perspective view of one embodiment of the present invention at a point in the transition from the deployed position of  FIG. 6  to the stowed position of  FIG. 1 ; and 
           [0016]      FIG. 8  illustrates a perspective view of one embodiment of the present invention at a point in the transition from the deployed position to the stowed position of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    While the invention is amenable to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and described in detail herein. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
         [0018]    The present invention provides a marine ladder  100  that is connected to a boat for boarding and disembarking and comprising a fixed section  200  and a rotatable section  300 . As illustrated in Figures, the ladder  100  is preferably fixedly mounted to the aft portion of boat, however, alternate locations for the ladder  100  mounting are within the scope of the present invention. Mounting bracket  102 , having a right side, a left side, a front side and a rear side is mounted to the boat surface by a variety of means, including bolting, screwing and the like, all of which will be well known to the skilled artisan. 
         [0019]    Fixed section  200  of ladder  100  comprises first  110  and second  120  handrails. First handrail  110  is shown with a first fixed proximal section  112  that is mounted or otherwise affixed to the left side of mounting bracket  102  at point A, proximate the rear side of bracket  102 , a first fixed curvilinear section  114  connected to the first proximal section  112  and a first fixed extension section  116  connected to the fixed curvilinear section  114 . 
         [0020]    The second handrail  120  is illustrated with a second fixed proximal section  122  mounted or otherwise affixed to the right side of mounting bracket  102  at point B, proximate the rear side of bracket  102 , a second fixed curvilinear section  124  connected to the fixed proximal section  122  and a second fixed extension section  126  connected to the fixed curvilinear section  124 . Fixed section  200  further comprises brackets  118  and  128  fixedly attaching fixed extension sections  116 ,  126 , respectively, to the front side of mounting bracket  102 . Certain embodiments of fixed section  200  may comprise, as illustrated, one or more step elements  150  fixedly connected between the first and second handrails  110 ,  120 . 
         [0021]    Fixed extension sections  116  and  126  comprise distal ends  117 ,  126 , respectively, where channels C 1 , C 2  are defined. 
         [0022]    Rotating section  300  of ladder  100  is a rigid structure that rotates in a single plane relative to fixed section  200 . Rotating section  300  comprises a left handrail L, capable of aligning with first handrail  110  of fixed section  200 ; a right handrail R, capable of aligning with second handrail  120  of fixed section  200  and with one or more step elements  150  disposed therebetween as in the Figures. Left and right handrails L, R each comprise a proximal end P, P′, that are rotatingly disposed within channels C 1 , C 2 , respectively, of first and second handrail  110 ,  120 . As illustrated, proximal ends P, P′ of left and right handrails L, R are rotatingly affixed within channels C 1 , C 2  by a fastener  147 , e.g., a nut and bolt system or the equivalent as the skilled artisan will readily recognize, each such equivalent fastener is within the scope of the present invention. 
         [0023]    Rotating section  300  further comprises two pivot point brackets B, B′ fixedly attached to the top T of each of proximal ends P, P′, respectively, of left and right handrails L, R. As can be seen in the Figures, when rotating section  300  is transitioning to the straightened, deployed position, the pivot point brackets B, B′ engage channels C 1  and C 2 , respectively, extending partially therethrough in certain embodiments. Pivot point brackets B, B′, are attached to the top T of each of proximal ends P, P′ of left and right handrails L, R, with an angle α therebetween. Angle α is illustrated as obtuse and approximately 135 degrees, though other angle degrees may be functionally equivalent and are also within the scope of the present invention. 
         [0024]    Identical first and second gas springs  400 ,  400 ′, comprising a gas-filled cylinder  402 ,  402 ′ and a rod  404 ,  404 ′, wherein the rod  404 ,  404 ′ is subject to the force of the gas within cylinder  402 ,  402 ′ and is translatable into and out of the cylinder  402 ,  404 ′ depending on the magnitude of the opposing forces that the rod is subjected to. As shown in  FIG. 2 , the force F 1  produced by the gas within cylinder  402 ,  402 ′ tends to push the rod  404 ,  404 ′ outwardly from cylinder  402 ,  402 ′ while any force applied to rod  404 ,  404 ′ by point brackets B, B′ tends to push the rod  404 ,  404 ′ in the opposing direction, i.e., translate back into the cylinder  402 ,  402 ′. The force, F1 or F2, that has a larger magnitude will dictate generally the translated position occupied by rod  404 ,  404 ′, relative to the cylinder  402 ,  402 ′ as well as point brackets B, B′. Gas springs  400 ,  404 ′ are illustrated as connecting between each of the brackets  118 ,  128  and the pivot point brackets B, B′, respectively. Thus, the gas spring cylinder  402  corresponding to the first gas spring  400  is fixedly connected to bracket  118  with its rod  404  rotatably connected to first pivot point bracket B. Similarly, the gas spring cylinder  402 ′ corresponding to the second gas spring  404 ′, is fixedly connected to bracket  128  with its rod  404 ′ rotatably connected to second pivot point bracket B′. The rotatable connections of rods  404 ,  404 ′ to first and second pivot point brackets B, B′, respectively, can be made in a variety of ways known to the skilled artisan, e.g., rod  404 ,  404 ′ may comprise an eyelet and thereby rotatably secured to first and second pivot point bracket B or B′ by a bolt or the equivalent. 
         [0025]    Having described the structure of the present invention, we now turn to the operation of the subject ladder.  FIGS. 1 ,  2  and  3  illustrate the ladder  100  in the stowed position. In this stowed position, the rotating section  300  is rotated upward and held in place by the force F1 relative to force F2 of gas springs  400 ,  400 ′ as described above. 
         [0026]      FIG. 4  illustrates the rotating section  300  transitioning downward as indicated by the arrow and out of the stowed position of  FIGS. 1-3  toward a deployed position as will be described further. To reach this transitional position, a user may have supplied sufficient force to the rotating section  300  to overcome force F1, so that force F2 overcomes force F1 and allows the rods  404 ,  404 ′ to translate into cylinders  402 ,  402 ′ with the result that rotating section  300  begins rotating downward around fasteners  147  and relative to fixed section  200 . The force F1 of gas springs  400 ,  400 ′ provides an continued oppositional force to the downwardly transitioning rotating section  300 , wherein the rods  404 ,  404 ′ are biased to be fully translated away from gas cylinders  402 ,  402 ′ by the force of the pressure of the gas within gas cylinders  402 ,  402 ′. This oppositional force allows the rotating section  300  a smooth and controlled downward rotation toward the deployed position. 
         [0027]    At a point in the transitional downward process, the mass of the rotating section  300  provides a force sufficient to overcome force F1, without aid of the user&#39;s added downward force on rotating section  300  as seen in  FIGS. 4 and 5 . To be clear, the user&#39;s added downward force is initially required to initiate the downward transition from stowed to deployed, but only until the mass of the rotating section  300  is positioned to provide sufficient force to overcome force F1 on its own. Once this point is reached, the rotating section  300  will continue rotating downward without need of any additional force application, using only gravitational force to overcome force F1. As described above, force F1 applied by gas springs  400 ,  400 ′ continues to provide oppositional force to the downwardly transitioning rotating section to allow the freely downwardly transitioning rotating section  300  a smooth and controlled downward rotation to the deployed position. In practice, the rotating section  300  may require a small amount of user-applied force to counteract the buoyancy effects of water, if the rotating section  300  is rotated downwardly into water, to complete fully the transition to deployed. 
         [0028]    The continued freely downward transition of rotation section  300 , i.e., without need of any additional downward force provided by, e.g., a user, results in the deployed position which is illustrated in  FIG. 6 . There, the handrails L, R of rotation section  300  substantially align with the fixed extension sections  116 ,  126  of fixed section  200 , placing the step elements  150  in the fixed section  200  and in the rotating section  300  in substantial alignment, thereby enabling the user to climb the step elements  150  at a constant pitch as in, e.g., a staircase. 
         [0029]    Once the deployed position of  FIG. 6  is achieved, the rods  404 ,  404 ′ are fully engaged within the respective cylinders  404 ,  402 ′ of gas springs  400 ,  400 ′, the gas springs  400 ,  400 ′, the fixed extension sections  116 ,  126 , and the pivot point brackets B, B′ may function to hold the ladder  100  in the deployed position. Pivot point brackets B, B′ may extend outwardly through channels C 1  and C 2  when fully deployed. 
         [0030]    Turning now to  FIGS. 7 and 8 , the assisted transition from the deployed position to the stowed position is illustrated. In  FIG. 7 , the rotating section  300  is beginning the upward rotation necessary to achieve fully stowed position. An initial upwardly, or horizontally, applied force is required to move the rotating section  300  out of the deployed position and to reach the upwardly transitional position of  FIG. 7 . This force can be provided by a user or, if the ladder  300  is mounted on the aft section of a boat, as illustrated in  FIG. 1 , then simply moving the boat forward in the water will provide sufficient force in certain embodiments to bring the rotating section out of the deployed position. 
         [0031]    At a point in the upward transition from deployed to stowed, the force F1 will overcome the downward forces, i.e., the mass of, on the rotating section. At this point, the forces F1 provided by gas springs  400 ,  400 ′ work to extend the rods  404 ,  404 ′ from the gas cylinders  402 ,  402 ′ with concurrent and smooth upward rotation of the rotating section as in  FIG. 8 . This assisted upward rotation to stowed position continues, without requirement of further force provided or applied by a user, until the rotating section  300  reaches the fully stowed position of  FIG. 1 . When fully stowed, the forces F1 applied by gas springs  400 ,  400 ′ keep the ladder  100  in the stowed position. 
         [0032]    The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification.