Abstract:
A mounting support ( 100, 200 ) for a marine vessel inboard drive propulsion system used in connection with a precision driveline includes a substantially cylindrical housing ( 107 ), one or more bearing assemblies ( 113 ) positioned within the cylindrical housing ( 107 ) for promoting rotation of a drive shaft ( 103 ) and one or more seals ( 119 ) typically located at both ends of the housing ( 107 ) for preventing water from contacting one or more of the bearing assemblies ( 113 ).

Description:
TECHNICAL FIELD 
     This invention relates in general to marine vessels and more particularly to a marine inboard propulsion system. 
     BACKGROUND 
     Marine vessels such as small water skiing boats and the like typically utilize inboard propeller drive propulsion systems. Unlike an outboard type of propulsion drive, the inboard drive system includes a motor within the boat that includes a drive shaft extending through the hull to the stern. The drive shaft drives a propeller. The advantage of inboard drive as opposed to other types of marine propulsion systems is that the rotation of the propeller causes fewer vortex turbulents generated by the propeller at the surface of the water. This permits a rapid start of the boat while allowing a water skier to traverse across a fewer rear wake vortices generated by the propeller without the water turbulents generally associated with other types of marine drives, such as outboard and stern drive systems. 
     As seen in prior art FIG. 1, one typical implementation of a inboard drive system  10  includes a motor  11  that uses a drive coupling  13  to rotate a drive shaft  15  through a stuffing box  17 . As best seen in prior art FIG. 2, the stuffing box  17  is a cylindrical structure that allows the drive shaft  15  to pass though the hull  19  of the boat. The stuffing box  17  generally is a flexible hose or rubber housing  21  sealed by hose clamps  23  or the like. The stuffmg box  17  is typically filled or “stuffed” with stuffing rope to prevent water leakage into the boat around the drive shaft  15 . Although the stuffing box  17  may be integrally fastened to the hull  19 , a user must continually insure that the packing nut  26  and hose clamps  23  are secured tightly so as to prevent water from entering inside the boat hull. Moreover, the stuffing box  17  must be precisely aligned with that portion of the boat&#39;s hull allowing the shaft to pass though. Since the shaft log  22  is fixed into position, any misalignment provides additional friction and wear to the shaft as it passes though the rubber housing  21  and packing nut  26 . 
     In FIG. 3, as the drive shaft  15  extends from the transmission coupling, through the stuffing box  17 , to be supported by a strut  25 . In some instances the drive shaft  15  may be enclosed within protective oil lubricated cover or tube  27  to prevent water, mud and/or other liquids from entering the enclosure. Alternatively, the drive shaft  15  will extend directly through the strut  25  which provides support for the drive shaft  15  before reaching a propeller (not shown). The strut  25  typically includes a mounting blade  31  which acts to fix the strut  25  at some predetermined position on the hull of the boat. The strut further includes some type of water lubricated bearing (not shown) such as a cutless bushing to allow the drive shaft  15  to spin within the strut  25  using water as a lubricant. Problems typically associated with this type of arrangement include the friction and continual wear of the water lubricated bearing. Over time excessive play can develop within the strut to the extent that the drive shaft will move laterally and/or radially and is no longer held into a fixed position during rotation. Hence, the strut requires continual attention, repair and replacement of the water lubricated bearing to insure the most optimum and efficient transfer of power to the propeller  29  to help reduce the undesired effects of vibration and movement. 
     In view of these shortcomings in the prior art drive system, the need exists to construct a more efficient means for providing support of drive shaft during its rotation in an inboard drive marine vessel propulsion system. This will insure very little maintenance and an efficient means to transfer power to a marine propeller while aiding in the support of the driveline. 
     SUMMARY OF THE INVENTION 
     Briefly, according to the invention, there is provided a mounting support for use in an inboard drive marine propulsion system. A center support and rear strut include one or more bearing assemblies and well as a seal at both ends of a support housing for reventing water from entering the support housing. Roller bearings are used to enhance rotational movement of a drive shaft while providing very little or no lateral movement. This greatly reduces wear and maintenance of the mounting support items to provide more efficient and less expensive operation of the marine vessel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention, which are believed to be novel, are set forth with particularly in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which: 
     FIG. 1 is a side view of the prior art inboard drive system for a marine vessel; 
     FIG. 2 is a side view of a prior art stuffing box used in an inboard drive propulsion system; 
     FIG. 3 is a side view of a prior art strut used in an inboard drive propulsion system; 
     FIG. 4 is a side cross-sectional view of the center support in accordance with the preferred embodiment of the invention; 
     FIG. 5 is a side cross-sectional view of the strut support in accordance with the preferred embodiment of the invention; 
     FIG. 6 is an exploded view of the center support; and 
     FIG. 7 is an exploded view of the strut support. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. 
     Referring now to FIGS. 4 to  7 , both a center support (FIG. 4) and a rear strut (FIG. 5) are shown and will be generally referred to as a center mounting support  100 . It should be recognized by those skilled in the art that embodiments other than a center support or strut are also possible. Although terms such as “center” as used throughout, it will be recognized that this refers to a support in the general sense and not at the precise center of the marine vessel. 
     As seen in FIGS. 4 and 6, a dripless center support  100  is mounted to the hull  101  of a inboard drive marine vessel so as to allow a drive shaft assembly  103  to gain support thereby holding it into a fixed position during its rotation. Additionally, the center mounting support  100  facilitates rotational movement while reducing whip of the drive shaft assembly  103  as well as preventing water or other liquid or semi-liquid materials such as mud from entering though the exterior of the hull  101 . In order to mount the center support  100  to prevent the entry of water while still providing a tight seal, the support  100  includes a flexible mounting ring  105 . The mounting ring  105  may be a substantially circular ring molded to a rubber membrane  111  that is fitted to the exterior of the housing such as cylindrical shaft body  107  of the mounting support  100 . The cylindrical shaft body  107  includes a rubber casing  110  to provide protection while immersed in water. The mounting ring  105  includes a plurality of mounting holes  108  to allow a screw  109  of other fastening means (not shown) to nest or secure the mounting ring  105  into a hole made within the hull  101 . A mounting seal  106  is used to provide a watertight fit between the mounting ring  105  and rubber membrane  111 . The mounting ring  105  is preferably comprised of a metallic material such as brass, steel, nibral, aluminum or the like to allow for a firm and secure mounting surface to the hull  101 . 
     In order to allow the mounting ring  105  to be mounted to the hull  101  while still having a certain degree of flexibility, a rubber membrane  111  is adhered from the back of the ring. The membrane  111  is pliable allowing the cylindrical shaft body  107  of the center support  100  to move and flex to a limited degree about the mounting ring  105 . This has a great advantage in that the center mounting support  100  may be mounted in any number of positions depending on the hull angle to the drive shaft assembly  103  which will extend through the hull  101 . This gives the center support  100  even greater versatility since it is not rigidly mounted into position that would allow only one angle of entry for the drive shaft assembly  103 . The flexible movement of the center support ring and tube also allows engine movement due to vibration, or shrink/swelling of steel, fiberglass and wood used in boat construction. The flex membrane  111  is adhered to the back of the mounting ring  105  and extends substantially along the sides of the cylindrical shaft body  107 . 
     As best seen in FIGS. 4 and 5, the cylindrical shaft body  107  is constructed of a metallic body or other ridged structure that may include a rubberized coating. The cylindrical shaft body  107  facilitates movement of the drive shaft assembly  103  though the boat hull  101 . The body is substantially hollow and includes a plurality of components to support the shaft in its rotational movement while providing the least amount of friction to the drive shaft assembly  103 . The drive shaft assembly  103  passes through one or more needle bearing or roller bearing assemblies  113  and a sleeve  114  that are used within the cylindrical shaft body  107  to enhance rotational movement of the drive shaft assembly  103 . Since the surface of the drive shaft assembly  103  will be manufactured of a relatively soft material such as stainless steel or the like, the sleeve  114  is adhered to the surface of the drive shaft assembly  103 . This enables the hardness of the surface of the drive shaft assembly to be increased to approximately a 60 Rockwell in order to allow the drive shaft assembly  103  to work more efficiently with the roller bearing assemblies  113  and seals  119 . Preferably, each roller bearing assembly  113  includes a plurality of substantially spherical roller ball bearings that move within a closed track. As will be further recognized by those skilled in the art, a needle bearing assembly will also be applicable since the bearings would surrounds and rotate about the drive shaft assembly  103 . The drive shaft assembly  103  is in contact with these bearings while the bearing work to both provides structural support for the drive shaft assembly  103  while facilitating rotation while within the center mounting support  100 . Preferably each roller bearing assembly  113  would be sealed and would require no lubrication or other maintenance. 
     In order to prevent water and/or other harmful material from entering the center mounting support  100 , one or more seal assemblies as used at one or both ends of the cylindrical shaft body  107  to insure that the components therein are impervious to external influence. A seal assembly may only be used at one end of the cylindrical shaft body  107  in the instance where one end of the support remains within the vessel and no water or other material would enter that end of the cylindrical shaft body  107 . As will be evident to those skilled in the art, water or other materials coming in contact with the bearing assemblies  113  would damage bearing and other components within the center support  100 . Each seal assembly includes a water deflector  115 , gasket  117  and a seal  119 . The water deflector  115  is frictionally engaged to the cylindrical drive shaft body  103  and is used to deflect water away from the outer face of the seal  119 . Any water that does enter past the water deflector  115  is further trapped outside the roller bearing assemblies  113  by a seal  119 . Typically the seal is made of a rubberized or other pliable material that will form a tight seal within the side body of the cylindrical shaft body  107  as well as the drive shaft  103 . As best seen in FIG. 4, the cylindrical shaft body includes a counterbore  121  that is cut within the center support  100  to a predetermined depth thereby reducing the inner diameter of the cylindrical shaft body  107  at its ends. The counterbore  121  permits the seal  119  to obtain a tightly sealed fit within the counterbore  121  while the deflector  115  is used to further seal any gap between the water seal  119  and the support tube. The use of these components to from a seal assembly essentially prevents water from entering the ends of the cylindrical shaft body  107  that would work to damage the roller bearing assemblies  113  therein. 
     As best seen in FIGS. 5 and 7, this embodiment illustrates a strut support assembly  200  depicted in the form of a strut  201  used at the rear of the marine vessel for the supporting a drive shaft assembly  103  before being attached to a propeller mount  211  and propeller (not shown). Similar to the center support  100 , the strut support assembly  200  includes a similar component structure within the strut  201  including a plurality of bearing assemblies and seal assemblies. The strut  201  includes a strut housing  203  having a blade  205  and flange  206  for fastening the strut  201  to the bottom of the vessel hull  207 . The blade  205  is preferably tapered on the leading edge for efficiency and set at an angle to allow the drive shaft assembly  103  to extend under the hull  207  at some predetermined angle. The blade  205  with flange  206  is typically fastened against the hull  207  though the use of screw fasteners  209  or the like. 
     The present invention allows for the quiet, smooth and efficient operation of an inboard drive marine vessel using the invention as described herein in as a center support and/or a strut. The invention reduces the vessel&#39;s operating expense while providing little maintenance or repair as compared with stuffing boxers or water lubricated struts used in prior art designs. While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.