Abstract:
A marine craft which includes a portable drive assembly temporarily attached to the transom, the portable drive assembly including an elongated drive housing enclosing an upper drive assembly and a lower driven assembly and a timing belt connecting the upper drive assembly to the lower driven assembly. The craft further includes an engine mounting plate attached externally to the drive housing adjacent the upper drive assembly perpendicular to the drive housing. The lower driven assembly also has a propeller shaft at least a portion of which is enclosed within a shaft housing attached to the drive housing adjacent the driven assembly, the shaft housing extending in excess of 18 inches beyond the drive housing, and a propeller attached to the propeller shaft.

Description:
REFERENCE TO RELATED APPLICATIONS 
   This is a continuation or continuation-in-part of commonly owned and co-pending non-provisional application Ser. No. 10/844,192 filed May 4, 2004, now U.S. Pat. Ser. No. 7,048,600 issued May 23, 2006, and which is a continuation-in-part of application No. 10/662,487 filed Sep. 15, 2003, now U.S. Pat. Ser. No. 7,052,340 issued May 30, 2006, claiming priority to provisional application No. 60/411,701 filed Sep. 17, 2002. This is also a continuation or continuation-in-part of the aforesaid commonly owned and co-pending non-provisional application 10/662,487, now U.S. Pat. Ser. No. 7,052,340. All of the foregoing applications are fully incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates generally to transom-mounted outboard motors for small marine watercraft and more particularly to air-cooled engines having belt driven propeller shafts for shallow draft watercraft. 
   GENERAL BACKGROUND 
   Small marine craft operating primarily in shallow water are often referred to as mud boats. Such boats are usually shallow draft flat bottom boats powered by in-board air cooled engines with outboard drives adapted to pass through the hull or transom for coupling to the engine, as disclosed by U.S. Pat. Nos. 941,827, 3,752,111 and 4,726,796. 
   In some cases small air cooled engines have been adapted for fixed attachment to a boat&#39;s transom for pivotal steering in the horizontal plane, with an extended drive shaft extending rearwardly to just below the water line at an angle of approximately 30 degrees as illustrated by Foreman in U.S. Pat. No. 6,302,750. 
   Other patents, such as Carter, et al. in U.S. Des. 259,488 illustrate the use of an air cooled engine pivotally mountable to the boat&#39;s transom with the same elongated drive shaft extending to just below the waterline perhaps at a somewhat greater angle, depending on the height of the transom. In most cases the drives are designed not to extend below the bottom of the hull. 
   Lais et al. and others disclose the use of electric motors in combination with a belt drive to maneuver small craft as is disclosed in U.S. Pat. Nos. 5,336,119 and 1,953,599. Obviously, such drives are not intended for high speed or for extended powering through mud or vegetation in shallow water. 
   The use of air cooled or water cooled marine engines coupled by belt to a transom mounted drive unit are well known within the art as being a most efficient means for driving a propeller shaft thereby reducing friction and improving mechanical advantage over right angle gear drives. Therefore, the use of a belt drive in combination with an air cooled engines as disclosed by Pignata in U.S. Pat. No. 5,435,763 seems to be an obvious choice. However, Pignata utilizes a unique internal propeller arrangement and with a through the transom coupling for an inboard air-cooled engine with pivotal kick-up capability or over the top of the transom arrangement. However, Pignata fails to fully disclose how either such arrangement may be steered effectively. While the Pignata apparatus may be useful in open water, it is far from obvious that it could be adapted for use in shallow water marsh with heavy mud and vegetation. The internal propeller housing must be located below the boat hull for water to be drawn effectively through the internal propeller blades. Therefore, if the propeller housing were above the bottom of the boat&#39;s hull, water flow would be blocked, Shallow draft boats are known to create a depression at speed for some distance directly behind the transom. It is therefore essential that the propeller shaft extend below the boat hull or beyond the water depression to make sufficient contact with the water to provide thrust and prevent cavitations. 
   Mud boats rely a great deal on propeller contact with the mud and the propeller&#39;s ability to cut the vegetation to help drive the boat. Hence the concept of having an elongated drive shaft extending at a shallow angle from above a boat&#39;s transom to just below the water surface has long been the excepted practice for mud boats. However, the use of a fixed inboard engine with a through transom coupling limits the apparatus to a particular boat and therefore may not be removed and mounted on another boat without extensive modifications. The use of a removable over the transom mounted air cooled engine with extended drive shaft is awkward and often limited to a relatively low horsepower engines. There is obviously a need to provide a relatively high horsepower air cooled engines adapted to an efficient belt drive for mounting to small, flat bottom boats in much the same manner as water cooled outboard engines. Such a driver must also be equipped with a foot that does not extend below the bottom of the boat but extends a sufficient distance behind the boat to insure the proper angle of attack when the propeller is in contact with mud and vegetation. 
   The use of a wide variety of commercially available air-cooled engines with 50 horsepower or more presents a wide range of problems that must be addressed and that are not encountered by conventionally manufactured outboard engine manufactures. By not manufacturing the engine, the drive must be adaptable to multiple engine configurations and drive train configurations. The weight of the engines must be considered and balanced in regard to the drive. Unique pivotal adjustments are necessary to insure safety and proper angles of attack at various speeds. The use of transmissions and clutches must also be considered in an attempt to reduce weight and cost. Conventional drives are inadequate due the constant inter-reaction with debris and mud including stumps and rocks. Therefore, consideration must be given to special propellers and their couplings when used as solids conveying means. Contact with underwater objects is a serious safety problem with mud boat drives since the engine can kick up or sideways causing serious harm to the operator. 
   It should be understood that a distinction should be made between air cooled engines utilizing a fully enclosed, self contained, circulating water system and water cooled marine engines that utilize the water in which they are submersed, for cooling. Some air cooled marine outboard engines have also been developed. However, for the purpose of this application air cooled engines used as an outboard drive are considered to be both air and self-contained water-cooled engines generally used for inboard drive engines or utility applications other than marine. 
   SUMMARY OF THE INVENTION 
   A relatively high horsepower air-cooled engine in one embodiment of this invention is adapted to an efficient belt drive assembly capable of being transom mounted to small flat bottom boats in much the same manner as conventional outboard engines. The drive is equipped with a lower drive shaft that does not extend below the bottom of the boat but extends a sufficient distance behind the boat to insure contact with the water for conventional propulsion. A unique pivotal arrangement allows the engine and drive assembly to be positioned for proper angle of attack when the propeller is in contact with mud and vegetation below the bottom of the boat. This arrangement allows for a much shorter turning radius than can be achieved by the related prior art transom mounted mud motor systems. The engine mount includes incremental tilt positioning capability and a pivotal horizontal steering handle. The propeller is capable of providing propulsion when in contact with solids such as mud and vegetation, and provides relatively fast hull speed in deep water. A clutch is provided to disengage the engine from the drive and an electric drive motor is provided in contact with the belt drive for turning the drive in a reverse direction. 
   The various embodiments and features of this invention will now become apparent from the following detailed description, the accompanying drawings and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which, like parts are given like reference numerals, and wherein: 
       FIG. 1  is a side elevation view of the preferred embodiment in the conventional drive position; 
       FIG. 2  is a side elevation view of the preferred embodiment in the mud engagement position; 
       FIG. 3  is a side elevation view of the preferred embodiment in the tilt up position; 
       FIG. 4  is an isometric view of the underside of the preferred embodiment with rotary actuator; 
       FIG. 5  is a partial cross section view of the underside of the preferred embodiment shown in  FIG. 4 ; 
       FIG. 6  is a side elevation view of the embodiment with manual positioner in the conventional drive position; 
       FIG. 7  is a side elevation view of the embodiment with manual positioner in the mud engagement position; 
       FIG. 8  is an isometric view of the underside of the embodiment with manual positioner; 
       FIG. 9  is a partial cross section view of the underside of the embodiment shown in  FIG. 8 ; 
       FIG. 10  is an exploded view of the pivotal assembly with actuator connection; 
       FIG. 10   a  is an exploded view of the pivotal assembly with manual positioning connection; 
       FIG. 11  is a top view of the drive assembly showing rotation in horizontal plane; 
       FIG. 12  is side elevation view of the pivoting bracket assembly showing range of motion in the vertical plane; 
       FIG. 13  is side elevation view of the pivoting bracket assembly in the kicked up position in the vertical plane; 
       FIG. 14  is a side cross-section view of the drive shaft assembly; 
       FIG. 15  is a partial isometric view of the drive shaft shown in  FIG. 14 ; and 
       FIG. 16  is side elevation view of the drive assembly showing the reverse drive motor. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The preferred embodiment  10  of the portable outboard drive assembly  12  as shown in  FIG. 1  utilizes a mounting bracket assembly comprising a conventional mounting bracket  14  for attaching the outboard drive assembly  12  to a boat&#39;s hull at transom  16 . The drive assembly  12  consisting principally of any number of commercially available air-cooled or self-contained water cooled utility engine assemblies  18  adaptively mounted to the frame assembly  20  at engine mounting plate  19 . The engines are connected by way of clutch and or transmission assemblies located within the transmission housing  22 , to a timing belt and gear drive assembly, also referred to herein as the upper drive assembly and lower driven assembly, located within the elongated vertical housing  24 , to which is connected the output drive shaft assembly located within the shaft housing  26  as previously discussed in at least our prior application Ser. No. 10/662,487, the disclosure of which is incorporated herein by reference. Shaft housing  26  extends in excess of 18 inches beyond vertical housing  24 . The upper drive assembly and the lower driven assembly further include respective timing pulleys operatively connected to a timing belt unobstructed or acted upon by other bodies, the pulleys and belt together forming a timing belt drive gear,  104 . In this case, the frame assembly  20  and vertical housing  24  are adaptively mounted in a pivotal and rotative manner to the pintle assembly  28 . This allows the entire drive assembly  12  to be pivotal about the pin assembly  30  (also referenced herein as the “first pivoting assembly”) located at the base of the pintle assembly  28  further disclosed in  FIG. 10 . This pivoting motion also allows the angle “Φ” of the drive assembly  12  to be increased relative to the pintle assembly  28  as shown in  FIGS. 1 and 2 , thus placing the propeller  32  below hull level  34 , while still allowing the drive assembly  12  to be rotated about the central axis  36  of the pintle assemble  28 . In addition the pintle assembly  28  can still be pivoted upwards positioning the propeller clear of the water  38  or at selected positions established by the pull pin  39  relative to the transom  16  as shown in  FIG. 3 . 
   As seen in  FIG. 4 , and in greater detail in  FIG. 10 , the lower pintle pin assembly  30  utilizes a pivot block  40  secured to the pintle assembly  28 , in a rotative manner about the rod  42  and is pivotally attached to the vertical housing  24  by a pair of clevis pad eyes  44  and a pivoting pin  46  passing through the pad eyes  44  and the block  40 . 
   As shown in  FIG. 5  and in more detail in  FIGS. 9 and 10   a  an upper pintle block  48  is secured to the pintle assembly  28  in a rotative manner about and by the rod  42 . The upper block  48  further includes the spreader plate  50  secured within the frame  20  by a pin  52  extending through slots  54  on each side of the frame  20  thus allowing the frame  20  to be pivotal relative to the pintle assembly  28 . 
   As shown in  FIG. 10  the pintle assembly  28  (also referenced herein as the “pivotal assembly”) further includes a second pivoting assembly formed by the pintle sleeve assembly  51  that is pivotally connected to the transom bracket  14  and rotational about pintle pivot pin  55  secured by a fastener such as a nut  57 . Further, the spreader plate  50  is pivotally secured to the pintle block  69  by a set of studs  59  when used with the manual positioner assembly  70  shown in  FIGS. 8 and 9 . However, an upper pintle block  48  is used in combination with rod clevis  67  pin  73  as seen in  FIG. 10   a  when used with the linear actuator assembly  58  seen in  FIG. 5 . 
   Generally, over the transom mud boat drive units are positioned by utilizing the extended handle  56  seen in  FIGS. 1 ,  2  and  3 . However, for safety and convenience the ability to pivot the handle as shown in  FIG. 3  is a distinct advantage. However, to achieve this an alternative method must be provided for pivotally positioning the drive assembly  12  in the vertical plane while using the handle for positioning in the horizontal plane. Two possible methods are illustrated herein. 
   The first being a linear actuator assembly  58  seen in  FIGS. 1 ,  2 ,  3 ,  4 , and  5 . The actuator assembly  58  is essentially comprised of an electric motor  60  a gear reducer  62  and a linear positioner  64  as shown in  FIG. 5  and better seen in detail in  FIG. 10 . In this arrangement, the base  66  of the actuator assembly  58  is fixed to the frame  20  while the rod  68  and its rod eye  67  member of the linear positioner  64  is pivotally attached to the pin  52 . 
   As illustrated in  FIG. 1  the linear actuator assembly  58 , when extended positions the drive shaft housing  26  in a neutral plane whereby the shaft housing is virtually perpendicular to the transom  16 . Retraction of the positioner  64  pivots the shaft housing in a negative direction thus forcing the drive shaft  26  and propeller  32  below the bottom hull level  34  as shown in  FIG. 2 . 
   The second positioner being a manual operated locking assembly  70  as shown in  FIG. 6 ,  FIG. 7 , and  FIG. 8  and in detail in  FIG. 9 . Looking first at  FIG. 9  we see that the manually operated locking assembly  70  is simply a lever or handle passing through the frame assembly  20 , with a ball  72  at one end and rotatably mounted at the opposite end  74  to the spreader bar pin  52  passing though the frame  20  and spreader plate  50  in a relatively loose manner. A spring  76  provides tension on the handle assembly  70  to insure indentation locking between the series of notches  78  adjacent the ball  72  and an edge of the frame  20 . 
   Looking back at  FIG. 6  we see that laterally moving the handle assembly  70  away from the spring  76  releases the frame  20  by moving the notches  78  in the handle away from the frame  20 . Therefore; by manually lifting the throttle handle  56  while holding the positioning handle  70  the drive assembly  12  can be easily tilted to a new position as shown in  FIG. 7 . 
   As shown in  FIG. 11  the overall length of the drive assembly  12  is considerably shorter than that of other drives used for this purpose and has a much smaller turning radius than that used by other mud boat drives. 
   It is the dual pivoting provided by a first pivoting assembly at point  63  and the second pivoting assembly at point  61  as again shown in  FIGS. 12 and 13  that provides the mounting bracket  14  with dual articulation of the drive  12  and thus allows the propeller  32  to be positioned in both a positive and negative draft angle by positioning the elongated drive housing either positively or negatively beyond vertical relative to the mounting bracket in the vertical plane. 
   The pivotal handle  56  provides steering and throttle control for the engine assembly  18  and further utilizes a unique locking mechanism  80  that allows the handle to be locked in the down position as shown in  FIGS. 1 and 2  and be tilted upwards as shown in  FIG. 3 . 
   Generally, the propeller  32  is secured to the drive shaft assembly  12  as shown and discussed previously. However, in some cases it has been found that allowing the propeller to slip or shear a pin in the conventional manner to prevent damage to the propeller and or damage to the drive shaft is not acceptable when the propeller is required to engage solid materials such as mud and grass. As illustrated in  FIG. 14  and  FIG. 15  a more solid connection is recommended. As seen in  FIG. 14  the shaft  81  may be modified as shown in  FIG. 15  by utilizing a hexagonal shape  82  corresponding to a hexagonal hub located within the propeller  32 . This prevents any possibility of shearing as a result of an encounter with immovable objects. However, the lower rutter fin  84  seen in  FIG. 14  tends to keep such encounters to a minimum. 
   Another important aspect of the air-cooled engine outboard drive assembly  12  is shown in  FIG. 16 . It has been found that in some cases it is advantageous not to use a transmission and simply utilize the high speed of the engine in a 1:1 ratio. However, this precludes the ability to reverse the drive. To still provide reverse capability, a clutch  100  is installed in the driveline between the engine output shaft  102  and the timing belt drive gear  104 . A D.C. voltage drive motor  106  is then mounted externally to the drive belt housing  24  with a gear  108  meshing with the belt drive gear  104 . This arrangement allows the belt drive gear  104  to be put into a neutral state when the clutch  100  is in engaged thus allowing the drive motor  106  to turn the belt drive in either direction as needed. 
   Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in any limiting sense.