Abstract:
In a first embodiment the combination boat dry dock and boat launching apparatus includes two planar dock sections pivotally connected to each other. The dock sections include cradle straps for supporting the hull of a boat with the longitudinal axis of the boat in substantial parallel relationship with the pivot axis of the dock sections. Each dock section is supported by two pontoons attached at proximal and distal portions of the dock sections. The two pontoons at respective proximal portions of the dock sections may be flooded with water to allow the proximal portions of the dock sections to descend below water level for launching of a boat. Air is introduced into these two pontoons for expelling water and thereby raising the dock sections above the water level. In a second embodiment, a constant buoyancy pontoon is mounted to each dock section intermediate the other pontoons. A pump and conduits transfer water between the proximal and distal pontoons of each dock section.

Description:
[0001]    This application is a continuation-in-part of application, Ser. No. 09/506,372, filed Feb. 18, 2000.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to dry docks for boats. In particular the present invention relates to a dry dock which will support a boat with its hull above the waterline and which will permit lowering of the boat hull below the waterline for launching purposes.  
           [0004]    2. Description of the Prior Art  
           [0005]    The 1869 patent to Richardson, U.S. Pat. No. 87,291, discloses a dry dock with air-tight tanks and a screw-rod mechanism for lowering of a boat into the water and for lifting of the boat from the water. This dry dock has the disadvantage of requiring substantial mechanical forces to operate the screw-rod mechanism.  
           [0006]    Muller U.S. Pat. No. 1,486,257 shows a dry dock having pontoons which may be partially flooded for tilting of the dry dock. This arrangement results in undesired tilting of a vessel supported by the dry dock.  
           [0007]    U.S. Pat. No. 3,114,535 to Burch discloses a boat lift with float units and a pulley arrangement for lifting and lowering of the boat. This boat lift suffers from the use of a somewhat complicated pulley mechanism and the requirement of substantial mechanical forces to operate the pulley mechanism.  
           [0008]    Roberts U.S. Pat. No. 3,315,627 shows a pneumatically operated floating dry dock. The employed is quite complicated requiring a number of ballast tanks, inflatable rubber bags and multiple valves for operating the tanks and bags.  
           [0009]    A floating dry dock for small boats is disclosed in Mann U.S. Pat. No. 3,412,702. The Mann patent is similar to the Burch patent mentioned above in that it uses a pulley system for raising and lowering of pontoons. Again, this arrangement has the disadvantage of requiring substantial mechanical forces to operate the pulley system.  
           [0010]    Rutter U.S. Pat. No. 4,018,179 shows a pontoon system for supporting watercraft on a body of water. This system requires tilting of the pontoons for carrying out a two-step procedure where the front portion of the boat is first lifted followed by raising of the rear portion of the boat.  
           [0011]    UK patent application GB 2 005 603 A discloses a floating dock which is variably buoyant and includes a pair of central rotatably mounted caissons to which outrigger floats are attached by arms. This application mentions, but does not show or describe in detail, that working platforms can be attached to the arms. However, the nature of the keel blocks attached to the caissons is such that the platforms could not be continuous and uninterrupted in form. Moreover, the construction of the floating dock in this UK publication is further complicated because the caissons are restricted to rotation about their respective central axes.  
           [0012]    For further background of the invention, attention is invited to the following patents: Francis 3,149,599; Mauritzen 3,610,192; Fukuda 3,638,437; King 3,895,592; and Meek et al. 6,131,526.  
         SUMMARY AND OBJECTS OF THE INVENTION  
         [0013]    The present invention includes a dry dock advantageously employing an articulated mechanism supported by a plurality of pontoons where one or more of the pontoons may be selectively flooded with water, or filled with a fluid lighter than water, for respectively lowering a boat into the water or lifting of the boat above the waterline.  
           [0014]    A primary object of the present invention is the provision of a dry dock of the type just described which takes advantage of buoyancy forces for lifting and lowering of a boat.  
           [0015]    A still further object of the present invention is the provision of a variable buoyancy dry dock and boat launching apparatus having a self-contained variable buoyancy system.  
           [0016]    Another object of the present invention is the provision of a dry dock which will support a boat with the hull of the boat completely above the waterline and which will permit lowering of the boat into the water for launching purposes.  
           [0017]    Still another object of the present invention is the provision of a dry dock of the type described which is of simple and easy-to-manufacture construction.  
       
    
    
       [0018]    These and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.  
       DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is an isometric view of the dry dock of a first embodiment of the present invention;  
         [0020]    [0020]FIG. 2 is a top plan view of the dry dock of FIG. 1;  
         [0021]    [0021]FIG. 3 is an end view of the dry dock in the docking position;  
         [0022]    [0022]FIG. 4 is an end view of the dry dock in the launching position;  
         [0023]    [0023]FIG. 5 is a side view of the dry dock in the docking position;  
         [0024]    [0024]FIG. 6 is an enlarged section taken along line  6 - 6  of FIG. 1;  
         [0025]    [0025]FIG. 7 is a top plan view of a second embodiment of the invention;  
         [0026]    [0026]FIG. 8 is an end view of the dry dock of FIG. 7 in the docking position;  
         [0027]    [0027]FIG. 9 is an end view of the FIG. 7 dry dock in the launching position;  
         [0028]    [0028]FIG. 10 is an isometric view of the second embodiment of the invention; and  
         [0029]    [0029]FIG. 11 is a side view of the FIG. 7 embodiment.  
     
    
     DESCRIPTION OF THE INVENTION  
       [0030]    Referring first to the embodiment of FIGS.  1 - 6 , the dry dock of the present invention, generally designated  10 , includes a pair of identical planar sections  11  and  12 . These sections may be made of wood planks or other suitable material. Each dock section is preferably made from a plurality of planks or boards forming a substantially continuous and uninterrupted deck or planar platform. The sections  11  and  12  are connected together at their proximal portions by a plurality of axially aligned hinge members  14  such that the sections  11  and  12  may pivot about an axis  15 .  
         [0031]    Section  11  mounts support blocks  16  and  17 . Similarly, section  12  mounts support blocks  20  and  21 . A hull cradle strap  24  is connected to support blocks  16  and  20 . In like manner, a second strap  25  is connected to support blocks  18  and  21 . These straps are adapted to engage and support the hull of a boat (not shown) for supporting the same with the longitudinal axis of the hull in parallel relationship with the pivot axis  15 . It will be understood that the present invention is primarily, although not exclusively, adapted for docking and launching of small boats. In the case of small boats, the hull may be manually positioned on the support straps  24  and  25  or so positioned by the use of a winch or the like with the longitudinal axis of the hull in substantial parallel relationship with the pivot axis  14 .  
         [0032]    Dock section  11  is supported by pontoons  26  and  28 . Preferably, pontoon  26  is connected to the section  11  at its distal portion; pontoon  28  is connected to section  11  at its proximal portion adjacent the hinge members  14 . In the same manner, a pontoon  30  is connected to the proximal portion of the section  12 ; a pontoon  32  is connected to the dock section  12  adjacent its distal portion. The various pontoons may be connected to the dry dock section by mounting members  34  as best seen in FIG. 6.  
         [0033]    The tubular walls and end walls of the pontoons  26 ,  28 ,  30  and  32  may be made of metal or plastic material and secured together to form closed chambers. Of course, the pontoons are by their very nature buoyant when filled with air or another fluid lighter than water.  
         [0034]    Referring to FIG. 6, the pontoon  28  has a first opening (not shown) communicating the interior of the pontoon with an L-shaped tubular member 36 . The pontoon  28  has a second opening (not shown) communicating the interior of the pontoon  28  with a second L-shaped tubular member  38 . A flexible tubular member, such as a hose section  40 , is preferably connected to the L-shaped member  38 . A lanyard  42  is connected to the free end of the hose  40  for securing this end of the hose to a cleat  44 .  
         [0035]    It will be understood that the pontoon  30  is of a construction identical with the pontoon  28  and thus includes a pair of openings communicating the interior of the pontoon with L-shaped tubular members. It should also be understood that the members  36 ,  38  need not be of L-shape configuration but of any suitable configuration for making connections with flexible tubular members.  
         [0036]    The operation of the dry dock of the first embodiment is as follows: When all four pontoons are in a buoyant state, that is to say, the pontoons  28  and  30  are filled with air or other fluid lighter than water, the dock will be in the configuration shown in FIGS.  1 - 3 ,  5  and  6  for supporting a boat above the waterline. In this configuration, the free ends of the hoses  40  connected to the pontoons  28  and  30  will be suitably supported above the waterline. When it is desired to launch a boat supported by the dry dock, the lanyards  42  will be released from the cleat  44  and the free ends of the hoses  40  will be placed below the waterline thus allowing the pontoons  28  and  30  to be flooded with water. The dry dock will then assume the configuration shown in FIG. 5 wherein the proximal portions of the sections  11  and  12  descend below the waterline for launching of the boat. The distal portions of the dry dock sections will remain above the waterline due to the buoyancy of the pontoons  26  and  32 .  
         [0037]    The dry dock may remain in the configuration of FIG. 5 until it is desired to dock the boat. Hoses (not shown) may be attached to the L-shaped tubular members  36  on the pontoons  28  and  30 ; these hoses will be connected to an air blower for forcing water from the pontoons  28  and  30 . The water will be discharged through the L-shape members  38  and the hoses  40 . When the pontoons  28  and  30  have been raised to the configuration shown in FIG. 3, the free ends of the hoses  40  will be supported above the waterline by the lanyards  42 . When the dry dock has been returned to the configuration shown in FIG. 3, the boat will have been raised and will be supported completely above the waterline.  
         [0038]    It should be understood that the distal portion of one of the dock sections  11  or  12  may be supported by attachment to an adjacent dock of conventional construction. In this event, one of the pontoons  26  or  32  may be eliminated. It will also be understood that a somewhat larger single pontoon could be substituted for the two pontoons  28  and  30 .  
         [0039]    A second embodiment of the invention is shown in FIGS.  7 - 11 . Parts of the second embodiment that correspond to the first embodiment of FIGS.  1 - 6  are designated by the prime form of numeral.  
         [0040]    The dock section  11 ′ has attached thereto a proximal pontoon  28 ′, a distal pontoon  26 ′ and an intermediate pontoon  46 . In like manner, the dock section  12 ′ is attached to a proximal pontoon  30 ′, a distal pontoon  32 ′ and an intermediate pontoon  48 . The pontoons  26 ′ and  32 ′ are preferably mounted in spaced relationship to the dock sections  11 ′ and  12 ′ by a plurality of legs  50 .  
         [0041]    A conduit  52 , which may be in the form of a pipe or hose, communicates with the interiors of the pontoons  26 ′ and  28 ′. Similarly, a conduit  54  communicates with the interiors of the pontoons  30 ′ and  32 ′. A pump  56 , shown diagrammatically in FIGS. 8 and 9, may be secured to the underside of the dock section  11 ′ and communicates with the conduit  52 . A second pump  58  secured to the underside of the dock section  12 ′ communicates with the conduit  54 .  
         [0042]    In a preferred form of the second embodiment of the invention, a liquid, such as water, having a volume substantially the same as the volume of one on the pontoons  26 ′ or  28 ′, is contained in the pontoon  26 ′ when the dock sections are in the configuration shown in FIG. 8. Another quantity of water, having a volume the same as the volume of one of the pontoon  30 ′ or  32 ′, is contained in the pontoon  32 ′ when the dock sections are in the FIG. 8 configuration. The pump  56  is in communication with the conduit  52  and transfers the self-contained quantity of water from the pontoon  26 ′ to the pontoon  28 ′ and from the pontoon  28 ′ to the pontoon  26 ′. An additional conduit (not shown) communicates with the pontoons  26 ′ and  28 ′ to permit the passage of air from the empty pontoon to the pontoon containing the quantity of water. In like manner, the pump  58  in communication with the conduit  54  transfers water from the pontoon  32 ′ to the pontoon  30 ′ and vice-versa. Again, another conduit (not shown) communicates with the pontoons  30 ′ and  32 ′ to permit the passage of air from one pontoon to the other.  
         [0043]    The pump  56  may be mounted within one of the pontoons  26 ′,  28 ′ or  46 . The pump  58  may also be mounted within one of the pontoons  30 ′,  32 ′ or  48 . Alternatively, a single pump could be mounted within one of the pontoons. In that event an additional conduit or conduits (not shown) would be provided to communicate with the pontoons  28 ′ and  30 ′ so that the single pump could transfer water back and forth between the pontoons  26 ′,  28 ′ and the pontoons  30 ′ and  32 ′. As is the case with the first embodiment of the invention described above, a single pontoon could replace the pontoons  28 ′ and  30 ′.  
         [0044]    When it is desire to launch a boat using the embodiment of FIGS.  7 - 11 , the pumps  56 ,  58  will be activated to transfer the self-contained liquid from the pontoons  26 ′ and  32 ′ to the pontoons  28 ′ and  30 ′. The dock sections will then assume the configuration shown in FIG. 9. When it is desired to raise the dock sections to the configuration shown in FIG. 8, the pumps will be activated to transfer the water from the pontoons  28 ′,  30 ′ to the pontoons  26 ′,  32 ′. It will be understood that in lieu of the self-contained liquid system of the second embodiment, water could be transferred to and from the pontoons  26 ′,  28 ′ and the pontoons  30 ′,  32 ′ using the system of the first embodiment.  
         [0045]    The dock sections  11 ′,  12 ′ may be connected to an existing dock by suitable pivot means (not shown) attached to the dock section adjacent the ends of the intermediate pontoons  46  and  48 . By reference to FIGS. 8 and 9, it will be apparent that the dock sections  11 ′ and  12 ′ will pivot about the pontoons  46  and  48 , respectively.  
         [0046]    Accordingly, it is seen that the present invention provides a dry dock that will support a boat with the hull completely out of the water. The dry dock of the invention permits ready launching and docking of a boat by alternately flooding the pontoons  28  and  30 , or the pontoons  28 ′ and  30 ′, and then forcing water from these pontoons.  
         [0047]    It is understood that the present invention is not to be limited to the embodiments shown and described herein but rather to all embodiments and modifications coming within the scope of the following claims.