Abstract:
An improved marine vessel includes a hull, the hull including a transom and having a predetermined waterline intersecting the hull and the transom. The vessel further includes an upper driveshaft disposed above the waterline, an engine disposed within the hull including an engine drive shaft, and a transmission shaft. The transmission shaft is configured to operatively couple the engine drive shaft to the upper drive shaft. The transmission shaft extends in an inclined orientation relative to a bottom of the hull between the engine drive shaft and the upper drive shaft. The vessel includes a stern drive attached to the transom, wherein the stern drive operatively couples the upper drive shaft to a propeller.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is a continuation-in-part of patent application Ser. No. 10/800,276, filed Mar. 12, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to marine inboard/outboard systems. More particularly, this invention relates to a system featuring a stern drive that is partially out of the water when in use and/or can be easily and completely lifted out of the water when not in use without the need to remove the stern drive from the vessel or the vessel from the water.  
       BACKGROUND OF THE INVENTION  
       [0003]     Internal combustion marine drive systems come in several basic types, distinguished by the placement and articulation of the engine and drivetrain components. Differing choices in the layout of these components yield varying results in reliability, performance and ease of maintenance of the systems as a whole.  
         [0004]     With an inboard system, a system featured mainly on larger vessels, the engine and almost all of the drivetrain components are placed inside the hull of the vessel towards the bottom, at or below the waterline. The engine and transmission are situated roughly equidistant from the bow, stern, port and starboard sides of the vessel. A propeller shaft extends rearwards from the transmission and tilts slightly downward, exiting the hull behind the inboard engine, ending underneath the bottom and towards the stern of the vessel. The engine of an inboard system can be a marinized automobile type four stroke engine or a purpose-built marine diesel and will typically have its own compartment within the hull. While an inboard engine takes up a good deal of room inside the hull that could otherwise be devoted to interior cabin space, it provides the vessel with excellent balance and a low center of gravity. In addition, the drivetrain used is generally considered the simplest and most efficient method of transferring torque from the engine to the propeller. However, because of the fixed position of the propeller shaft and reliance on a separate stern mounted rudder system, the inboard system is not as maneuverable at low speeds or while in reverse as are other systems.  
         [0005]     In contrast an outboard system allows a user to steer by rotating the propeller shaft itself through a large arc. This is made possible by providing the engine, drivetrain and propeller all encased within a single unit externally mounted on the transom of the vessel. Because steering is achieved by rotating this unit as a whole to change the direction of thrust of the propeller, excellent low speed maneuverability is achieved. While the top portion of an outboard system contains the engine components and remains above the waterline, the bottom portion containing the drivetrain and propeller shaft extends beneath the waterline.  
         [0006]     The placement of an outboard system on the transom of a vessel tends to make the vessel as a whole heavier at the stern. To minimize the negative effect an outboard system has on the weight balance of a vessel, these systems are designed to be lighter and more compact than an inboard system of comparable power. An outboard system of moderate size can readily be manually removed and replaced on a vessel by a single user. Outboard systems are an attractive option because of their low cost and simplicity.  
         [0007]     As a compromise between the inboard system and the outboard system, an inboard/outboard (“I/O”) system combines elements of both aforementioned systems to maximize the utility of each. In an I/O system, as with a true inboard system, the engine is placed inside the hull at or below the waterline and equidistant from the port and starboard sides of the vessel. However the I/O system differs in its placement of the engine towards the stern of the vessel near the transom. An engine driveshaft extends from the engine and exits the vessel through the transom below the waterline. The portion of an I/O system mounted externally on the transom is customarily known as the stern drive, or outdrive, and essentially resembles the lower portion of an outboard system. The stern drive receives the engine driveshaft exiting the vessel through the transom below the waterline and is attached to the transom of the vessel with six large bolts and nuts.  
         [0008]     The interior of the stern drive contains a universal joint which enables the rotating shafts housed within the stern drive to turn in a horizontal plane and tilt in a vertical plane while transferring torque from the engine to the propeller shaft. The universal joint is necessary because the stern drive itself must be able to turn and tilt as a unit in order to steer the vessel and to trim the attitude of the vessel, respectively. As is known to those skilled in the art, the stern drive incorporates a gimble unit or other means which allow the lower portion of the unit to be adjusted in the manner described above. See, for example Bland et al U.S. Pat. No. 6,296,535, incorporated herein by reference.  
         [0009]     Also provided are a series of gears that allow the rotating shafts inside the stern drive to connect with one another through a series of ninety degree turns. Specifically, these gears allow the engine driveshaft to connect with a vertical shaft, and further allow this vertical shaft to connect with a horizontal propeller shaft. A housing, bellows, and/or other means protect the mechanical components of the stern drive such as the aforementioned gears and universal joint from the corrosive effects of the salt water environment of the stern drive.  
         [0010]     The advantages of an I/O system are that a large, fuel efficient automotive type four stroke or marinized diesel engine can be used as with a true inboard. The weight balance of the vessel, while not as good as with a true inboard given the aft placement of the engine, is still better than an outboard system where the weight of the engine rests entirely outside the hull of the vessel. The steering and trimming functionalities of an outboard system are preserved, as is a good deal of interior cabin space in the vessel given the sternward placement of the engine.  
         [0011]     Despite their advantages, prior art I/O systems suffer from the notable drawback of susceptibility to failure caused by salt water damage. Because the stern drives in prior art I/O systems are permanently placed below the waterline, their interior mechanical components are vulnerable to damage caused by seawater entering the stern drive. Although bellows are provided to protect the interior mechanical components of the stern drive from the salt water environment in which the stern drive is located, leaks in said bellows do occur necessitating costly repairs for the user. Even if a leak in said bellows does not occur, it is still necessary to replace said bellows on a regular basis, which is also costly for the user.  
         [0012]     In addition, routine maintenance tasks such as oil changes and the like can only be performed on the stern drive with the vessel itself removed from the water. Cleaning the exterior housing of the stern drive to remove algae and barnacles can only be performed with the vessel removed from the water or by a trained diver.  
         [0013]     As described in the foregoing, a general drawback to I/O systems is the position of the engine near the stern of the vessel. Such a position places the center of gravity of the vessel toward the stern of the vessel. Accordingly, a more unbalanced load distribution is produced by typical I/O systems. The unbalanced load distribution hinders the performance of vessels having I/O systems in comparison to vessels having inboard systems. For example, vessels having an inboard system tend to plane-off better than vessels having outboard systems or I/O systems.  
         [0014]     There exists a need for a stern drive for an I/O system that eliminates the problems stated above. It is understood that the present invention relates to a wide range of prior art I/O systems including embodiments not explicitly discussed above. For example, in an alternative embodiment of the prior art I/O system, the stern drive additionally comprises two propellers as well as mechanical means to turn two propellers in opposite directions. Otherwise, this alternative embodiment of the prior art is substantially the same as the system described above. The improved marine inboard/outboard system of the present invention is an improvement over both these embodiments of the prior art.  
       SUMMARY OF THE INVENTION  
       [0015]     In accordance with one aspect of the present disclosure, an improved marine vessel includes a hull, the hull including a transom and having a predetermined waterline intersecting the hull and the transom. The vessel further includes an upper driveshaft disposed above the waterline, an engine disposed within the hull including an engine drive shaft, and a transmission shaft. The transmission shaft is configured to operatively couple the engine drive shaft to the upper drive shaft. The transmission shaft extends in an inclined orientation relative to a bottom of the hull between the engine drive shaft and the upper drive shaft. The vessel includes a stern drive attached to the transom, wherein the stern drive operatively couples the upper drive shaft to a propeller.  
         [0016]     In accordance with another aspect of the present disclosure, an improved marine vessel includes a hull, the hull including a transom and having a predetermined waterline intersecting the hull and the transom. The vessel further includes an upper driveshaft disposed above the waterline, an engine disposed within the hull an having an engine driveshaft. The engine drive shaft has a horizontal distance and a vertical distance relative to the upper drive shaft to define an inclined distance between the upper drive shaft and the engine drive shaft. The vessel includes a transmission shaft that extends along the inclined distance, wherein the transmission shaft operatively couples the engine drive shaft to the upper drive shaft. The vessel further includes a stern drive that is attached to the transom. The stern drive includes a vertical shaft driven by the upper driveshaft, a propeller shaft driven by the vertical shaft, and a housing attached to the transom and enclosing the vertical shaft.  
         [0017]     In accordance with yet another aspect of the present disclosure, a drive system for a marine vessel having a hull with a transom, an engine disposed within the hull and having an engine drive shaft, and a stern drive having a propeller shaft coupled to a propeller, the drive system includes an upper driveshaft configured to be disposed outside the hull and above a predetermined waterline intersecting the transom. The drive system further includes a transmission shaft that is configured to extend through an inclined distance defined by a horizontal distance and a vertical distance between the upper drive shaft and the engine drive shaft. The transmission shaft is further configured to operatively couple the engine drive shaft to the upper drive shaft. A vertical shaft is configured to operatively couple to the upper drive shaft with a set of upper gears and configured to operatively couple to the propeller shaft with a set of lower gears. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a side view of a prior art stern drive having a conventional placement and articulation;  
         [0019]      FIG. 2  is a side view of an improved stern drive configuration;  
         [0020]      FIG. 3  is a side view of the improved stern drive of  FIG. 1  using a belt and pulley system in the drivetrain;  
         [0021]      FIG. 4  is a side view of the improved stern drive of  FIG. 1  wherein the engine is placed on the same level as the top portion of the stern drive for a simplified drivetrain;  
         [0022]      FIG. 5  is a side view of a further embodiment of an improved stern drive wherein the stern drive is in a substantially horizontal position;  
         [0023]      FIG. 6  is a side view of an improved inboard/outboard system constructed in accordance with the teachings of the present disclosure; and  
         [0024]      FIG. 7  is a side view of the stern drive of  FIG. 6  shown with the stern drive pivoted out of the water. 
     
    
       [0025]     Before any embodiment of the invention is explained in detail it is to be understood that the invention is not limited in its application to the exemplary details of construction and arrangements of components set forth in the following description or illustrated in the drawings. For example, although the actuator will be described in the context of a hydraulic cylinder, it will be appreciated that in lieu of using a hydraulic actuator, an electromechanical actuator could be employed to impart the thrust required to trim the stern drive propulsion system. Thus, the invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the terminology used herein is for the purpose of illustrative description and should not be regarded as limiting.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     Referring now to the drawings, and more particularly to  FIG. 1 , there is shown an illustration of a prior art design of an I/O system. A side view of the system is shown installed in a vessel  40  having a transom  41  and bottom hull  42 . A stern drive  60  is shown comprising a stern drive mounting plate  90 , a housing  61  attached to the stern drive mounting plate  90  and the components contained therein, described in detail below. The stern drive mounting plate  90  is attached to the transom  41  of the vessel  40  by six large bolts (not shown). As is known to those skilled in the art, the stern drive  60  can include a gimble unit (not shown) or other suitable means interposed between the stern drive mounting plate  90  and the housing  61  which allow the housing  61  to pivot in relation to the stern drive mounting plate  90  about a pivot  91 . See gimble unit 30 of FIG. 3, in Bland et al U.S. Pat. No. 6,296,535.  
         [0027]     An engine  50  is shown within the vessel  40  partially below the waterline  45 . An engine driveshaft  54  extends from the engine  50  and connects to a flywheel  55 . As is known to those skilled in the art, the flywheel  55  is used for the smooth operation of the engine  50  and can be engaged by a starter motor (not shown) when a user desires to start the engine  50 .  
         [0028]     The engine driveshaft  54  passes though the flywheel  55  and a gimble bearing  62  before passing through the transom  41  to enter the stern drive  60 . For increased stability, multiple gimble bearings  62  may be used, and they may be disposed to support the upper driveshaft on either or both sides of the transom  41 . The stern drive  60  is shown here completely submerged below the waterline  45 . A bellows  71  is provided in the top portion of the stern drive  60  to protect the mechanical components therein, including a universal joint  63  and gears  64 , from corrosion. The engine driveshaft  54  connects to the universal joint  63 . The universal joint  63  connects through a shaft to the gears  64 . The gears  64  connect to a vertical shaft  65  which runs downward through the housing  61  of the stern drive  60  to connect with gears  66 . The gears  66  connect to a propeller shaft  67 , which in turn is connected to a propeller  68 .  
         [0029]     An anti-cavitation plate  69  is part of the stern drive housing  61 . An actuator  70  extends from the stern drive mounting plate  90  to engage the housing  61 . The actuator is comprised of a cylinder  72  and piston  73 . The actuator  70  is attached to the stern drive mounting plate  90  and the housing  61  using a pair of actuator hinges  72 . The actuator hinges  72  allows the actuator  70  to change its pitch as it extends and contracts to adjust the lower portion of the stern drive  60 .  
         [0030]     The actuator  70  rotates the stern drive  60  about the universal joint  63  and gimble unit or other means known in the art, both of which allow rotation in relation to the pivot  91  of the components they connect. The universal joint pivot location may be different than the stern drive pivot  91 , if desired. This actuator allows a user of the stern drive  60  to trim the attitude of the stern drive  60 . This actuator also allows a user to raise the stern drive  60  so that the vessel can be held low on a trailer while ensuring ground clearance of the stern drive  60 . However, the stern drive  60  cannot be lifted completely out of the water in the prior art I/O system shown in  FIG. 1 .  
         [0031]     The I/O system shown in  FIG. 1  also includes an exhaust conduit  52  connected to the manifold  51  of the engine  50 . The exhaust conduit  52  is routed through the stern drive  60  and exits the housing  61  of the stern drive  60  through the anti-cavitation plate  69 . A water pump  75  is connected to the water intake  76 . The water intake  76  takes water into the stern drive  60  and passes it through the transom  41  to the interior of the vessel  40  in order to cool the engine  50 .  
         [0032]      FIG. 2  shows one embodiment of the present improved marine I/O system. The stern drive  60  is shown comprising a stern drive mounting plate  90 , a housing  61  and the components contained therein, described in detail below. The stern drive mounting plate  90  is attached to the transom  41  by six large nuts and bolts (not shown). As described above and known in the prior art, the stern drive  60  can include a gimble unit (not shown) or other suitable means interposed between the stern drive mounting plate  90  and the housing  61  which allow the housing  61  to pivot in relation to the stern drive mounting plate  90  about a pivot  91 . An anti-cavitation plate  69  is provided as part of the housing  61 .  
         [0033]     An upper driveshaft  57  is positioned so that it exits the transom  41  of the vessel  40  above the waterline  45 . The stern drive  60  is positioned on the transom  41  in turn so that the mechanical components in the top portion of the stern drive, including the universal joint  63  and gears  64 , lie in the same horizontal plane as the upper driveshaft  57 . This has the result that the universal joint  63  and the gears  64  will also lie above the waterline  45 . Because of this, the universal joint  63  and the gears  64  are at much less risk of damage from the salt water environment. A bellows  71  may be used enclosing these components as in the prior art to further reduce this risk.  
         [0034]     The upper driveshaft  57  passes though a gimble bearing  62  before passing through the transom  41  to enter the interior of the stern drive  60 . For increased stability, multiple gimble bearings  62  may be used, and they may be disposed to support the upper driveshaft on either or both sides of the transom  41 . The upper driveshaft  57  enters the interior of the stern drive  60  and engages the universal joint  63 , which in turn engages the gears  64 . The gears  64  connect to a vertical shaft  65  which runs downward through the housing  61  of the stern drive  60 , crossing the level of the waterline  45  to connect with gears  66 . The propeller shaft  67  is connected to the gears  66 , and is in turn connected to the propeller  68 .  
         [0035]     The actuator  70  rotates the lower portion of the stern drive  60  about the pivot  91 . The actuator  70  is comprised of a piston  73  and a cylinder  74 . In the present stern drive  60 , the actuator  70  extends from the transom  41  to a cantilever  77  provided attached to the housing  61 . The actuator  70  is attached to the transom  41  and the cantilever  77  using a pair of actuator hinges  72 . The actuator hinges  72  allow the actuator  70  to change its pitch as it extends and contracts to adjust the position of the stern drive  60 .  
         [0036]     By attaching one end of the actuator  70  to the transom  41  directly or through an actuator mounting plate (not shown) rather than to the stern drive mounting plate  90  as in the prior art, and by attaching the other end of the actuator  70  to a cantilever  77 , a much longer actuator  70  can be used than in the prior art. The elongated actuator  70  of the present invention can effectively reposition the stern drive  60  between an operative position below the waterline  45  and a maintenance position wherein the stern drive  60  is lifted partially or even completely above the waterline  45 . Because the stern drive  60  is mounted on the transom  41  such that the top portion of stern drive  60  lies above the waterline  45 , this rotation can result in the entire stern drive  60  being above the waterline  45  when the actuator  70  is fully extended.  
         [0037]     The I/O system shown in  FIG. 2  differs from the prior art in the additional respect that the exhaust conduit  52  and the water intake  76  of the engine  50  are both routed directly through the hull of the vessel  40  and do not pass through the stern drive  60 . As shown in  FIG. 2 , the exhaust conduit  52  runs from the manifold  51  of the engine  50  through the transom  41  above the waterline  45 . The exhaust conduit  52  incorporates a muffler  53 . In addition,  FIG. 2  shows a water pump  75  connected to a water intake  76  which is attached to the bottom hull  42  of the vessel  40 . The water pump  75  may in turn be connected to a cooling system  79  connected to the engine  50 . Because of these improvements, the lower portion of the housing  61  of the stern drive  60  can be constructed as a single, watertight unit and may employ aluminum or another suitable material.  
         [0038]      FIG. 2  shows the present stern drive  60  placed so that the portion of the stern drive  60  that attaches to the transom  41  is above the waterline. However, the engine  50  is placed at or below the waterline within the hull of the vessel  40 , as is standard with I/O systems. Because the upper driveshaft  57  of the stern drive  60  is not on the same level with the engine driveshaft  54 , the problem arises of how to transfer power from the latter to the former. In  FIG. 2 a  flywheel  55  is shown attached to the engine driveshaft  54 . The flywheel  55  has teeth on it which enable it to engage drive gear  56 . Drive gear  56  is in turn attached to the upper driveshaft  57 , which passes through the transom  41  to the interior of stern drive  60 .  
         [0039]     Various methods may be used to allow the upper driveshaft  57  of the stern drive  60  to exit the transom  41  above the waterline  45 . In an alternative embodiment shown in  FIG. 3 , the engine driveshaft  54  extends from the engine  50  and connects to a flywheel  55 . The flywheel  55  rotatably engages a lower pulley  80 . The lower pulley  80  engages a belt  81  which turns an upper pulley  82 . The upper pulley  82  is connected to the upper driveshaft  57 . A plurality of belts may also be used to provide redundancy and ensure the smooth operation of the system in the event of a failure of any single belt.  
         [0040]     Alternately, the engine  50  may be placed in a higher position within the vessel  40  to match the raised placement of the stern drive  60 , as shown in  FIG. 4 . In this embodiment, the engine driveshaft  54  extends from the engine  50  and connects to a flywheel  55 . The flywheel  55  connects to an upper driveshaft  57 . In this manner the mechanical linkages between the engine  50  and the stern drive  60  can be the same simple components as shown in the prior art  FIG. 1 , while still allowing for a raised placement of the stern drive  60  on the transom  41 .  FIG. 5  shows a side view of a further embodiment of an improved stern drive wherein the stern drive  60  is in a substantially horizontal position.  
         [0041]      FIGS. 6 and 7  show an I/O system  100  constructed in accordance with the teachings of another embodiment of the present disclosure. A stern drive  160  of the I/O system  100  includes a mounting plate  190 , by which the stern drive  160  is mounted to and supported by the transom  41 . The stern drive  160  includes a housing  161 , in which componets of the stern drive  160  are supported and protected from exposure to water. As described above and is known to one of ordinary skill in the art, the stern drive  160  can include a gimble unit  162  or other suitable means interposed between the stern drive mounting plate  190  and the housing  161  that allows the housing  161  to pivot in relation to the stern drive mounting plate  190  about a pivot  191 .  
         [0042]     The I/O system  100  includes an upper driveshaft  157 , which is positioned above the waterline  45  proximate to the transom  41 . Accordingly, the stern drive  160  is positioned on the transom  41  so that the mechanical components in the top portion of the stern drive  160 , including the gears  164  and any other joints or bearings (not shown) of the stern drive  160  lie in the same horizontal plane as the upper driveshaft  157 . Accordingly, the upper drive shaft  157 , the gears  164  and any other joints or bearings of the top portion of the stern drive  160  are at much less risk of damage from the salt water environment. A bellows  171  may be used enclosing these components as in the prior art to further reduce this risk.  
         [0043]     An engine  150  is housed in the vessel  40  between the bow and the stern of the vessel  40 . However, to provide a balanced load distribution for the vessel  40 , the engine  150  of the I/O system  100  may be proximate to a mid-section of the vessel  40 . For example, the engine  150  may be housed proximate to the center of gravity of the vessel  40 . Accordingly, as shown in  FIG. 6 , the engine drive shaft  154  may be horizontally offset from the upper drive shaft  157  by a horizontal distance X and vertically offset from the upper drive shaft  157  by a vertical distance Y. The distances X and Y define an inclined distance D having an inclination angle α relative to a bottom of the vessel  40  and extending between the engine drive shaft  154  and the upper drive shaft  157 . The distance D and the inclination angle α can vary depending on the location of engine drive shaft  154  relative to the upper drive shaft  157 . As a result, the farther the engine  150  is positioned relative to the stern of the vessel  40 , the longer the distance D and the shallower the angle α will be.  
         [0044]     The engine drive shaft  154  is connected to a transmission shaft  159  by a lower joint  155 . The transmission shaft  159  extends through the transom  41  and is connected to the upper drive shaft  157  by an upper joint  163 . Thus, the transmission shaft  159  is inclined relative to both the engine drive shaft  154  and the upper drive shaft  157  and extends along or substantially parallel with the distance D. The lower joint  155  and/or the upper joint  163  may be a universal joint. However, either of the joints  155  and  163  may be any type of joint or a plurality of joints that can provide rotational coupling between the engine drive shaft  154  and the transmission shaft  159 , and the transmission shaft  159  and the upper drive shaft  157 , respectively, at the inclination angle α. To provide stability for the transmission shaft  159  and support for the rotational coupling thereof with the engine drive shaft  154  and the upper drive shaft  157 , the transmission shaft  159  may include a lower gimbal bearing  156  disposed proximate to the lower joint  155  and an upper gimbal bearing  162  disposed proximate to the upper joint  163 .  
         [0045]     The upper driveshaft  157  engages the gears  164 . The gears  164  connect to a vertical shaft  165  which runs downward through the housing  161  of the stern drive  160 , crossing the level of the waterline  45  to connect with gears  166 . A propeller shaft  167  is connected to the gears  166 , and is in turn connected to a propeller  168 .  
         [0046]     Referring to  FIG. 7  an actuator  170  can rotate the lower portion of the stern drive  160  about the pivot  191 . The actuator  170  is comprised of a piston  173  and a cylinder  174 . In the present stern drive  160 , the actuator  170  extends from the transom  41  to a cantilever  177  attached to the housing  161 . The actuator  170  is attached to the transom  41  and the cantilever  177  using a pair of actuator hinges  172 . The actuator hinges  172  allow the actuator  170  to change its pitch as it extends and contracts to adjust the position of the stern drive  160 .  
         [0047]     By attaching one end of the actuator  170  to the transom  41  directly or through an actuator mounting plate (not shown) rather than to the stern drive mounting plate  190  as in the prior art, and by attaching the other end of the actuator  170  to a cantilever  177 , a much longer actuator  170  can be used than in the prior art. The elongated actuator  170  of the present invention can effectively reposition the stern drive  160  between an operative position below the waterline  45  and a maintenance position wherein the stern drive  160  is lifted partially or even completely above the waterline  45 . Because the stern drive  160  is mounted on the transom  41  such that the top portion of stern drive  160  lies above the waterline  45 , this rotation can result in the entire stern drive  160  being above the waterline  45  when the actuator  170  is fully extended. A water intake  176  may be routed directly through the hull of the vessel  40 . A water pump  175  is connected to the water intake  176 . The water pump  175  is in turn connected to a cooling system  179  connected to the engine  150 .  
         [0048]     While a particular form of the disclosure has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the disclosure be limited, except as by the appended claims.