Abstract:
A boat propulsion system includes a plurality of positive displacement pumps which having high discharge head and having inlets and outlets therein and a controlling panel having circuits, wherein the pumps are mounted on a bottom of a boat and driven by a motive power. By means of different positions of the outlets in each pump or different power transmission of each pump and cooperating with using the controlling panel, the boat can therefore move toward desired directions and enhancing power transmission by the pumps are drawn uniform flow when the boat is moved.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a boat propulsion system for being replaceable to a rudder controlling moving direction and enhancing power transmission during the boat is moved. 
   2. Prior Art 
   Boat propulsion systems are known as primary power for moving boats. The power can be adjusted to different levels by marine engine in order to control moving speed of a boat, and if cooperate with a rudder, the boat can turn port or starboard. 
   However, a boat&#39;s movement is generally affected by varied reasons such as kinds of propellers, rudders and positions where they are mounted on. Though the propellers and rudders can make the boat move and turn, they still suffer from several drawbacks as described below:
         1. unstable power transmission-a propeller is generating vortex by way of rotating blades, and the vortex facilitates the boat move, however, the vortex may affect the power transmission and result in unstable transmission.   2. over-big turning radius-a boat can change its moving directions by utilizing a rudder swinging; the rudder operates based on the “Bernoulli Theory”, that is, an equation that relates the fluid pressure and velocity acting along the surface of a wing. It also can apply to a boat&#39;s rudder. The rudder is a curved shape while the opposite side is relatively flat. Thus, when fluid passes over the rudder, that stream over the curved side is squeezed into a smaller area than that stream passing the relatively flat side. Thus, a higher pressure exists on the relatively flat surface of the rudder and a lower pressure on the curved surface. As the hydraulic pressure difference generated between the two surfaces of the rudder, a boat can turn according to variation of an angle given by the rudder swinging. However, such a turning of boat requires relatively big radius, and it causes the boat cannot turn flexibility.   3. more time to make a turn-as described above, a big turning radius, of course, requires more time to complete the process of turning.       

   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a boat propulsion system having a plurality of positive displacement pumps for generating uniform jet-flow of fluid as the thrust power source and thus can enhance power transmission efficiency and stability. 
   Another object of the present invention is to provide a boat propulsion system for controlling moving direction and requiring smaller radius and being able to replace a conventional rudder. 
   To achieve the above object, a boat propulsion system in accordance with the present invention includes a plurality of positive displacement pumps which having high discharge head and having inlets and outlets therein and a controlling panel having circuits, wherein the pumps are mounted on the bottom of a boat and driven by a motive power. By means of different positions of the outlets in each pump and different arrangement of each pump and cooperating with using the controlling panel, the boat can therefore move toward desired directions. 
   Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiment of the present invention with the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an perspective view of a boat propulsion system in accordance with a preferred embodiment of the present invention, and the boat propulsion system is mounted on a boat; 
       FIGS. 2 and 3  are schematic views of two types of pumps; 
       FIG. 4  is a plan view of a transmission apparatus being pivotally connected with the pumps; 
       FIG. 5  is a plan view of a layout of inlets and outlets of the pumps. 
       FIGS. 6-10  are schematic views illustrating the boat moving forwardly, turning right, turning left, moving backwardly and turning round; and 
       FIGS. 11-13  are schematic views of another embodiment illustrating the boat moving forwardly, turning right, turning left, moving backwardly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 to 5 , a boat propulsion system  1  in accordance with the first embodiment of the present invention comprises: a plurality of positive displacement pumps  2  mounted on a bottom of a boat  9 , a controlling panel  3 , and a transmission apparatus  4 . Referring to  FIG. 1 , a motive power  90  of the boat  9  is disposed at the rear of the boat, and the controlling panel  3  is set nearby a steering wheel  91  having circuits therein (not shown) for switching on or off each pump  2 . The controlling panel  3  further has controlling buttons with signs, shapes or descriptions for different functions such as forward button  30 , backward button  31 , turning left button  32 , turning right button  33 , and turning around button  34 ,  35 . 
   Referring to  FIGS. 2 and 3 , the pumps  2  are driven by the motive power  90 . Each pump  2  comprises a housing  20  having a driving chamber  21 , an inlet  201  and an outlet  202  therein, both the inlet  201  and outlet  202  communicating with the driving chamber  21 . A first gear rotor  22  and a second gear rotor  23  are assembled in the driving chamber  21  and are engaged with each other. In  FIG. 2 , the inlet  201  is positioned perpendicularly to the outlet  202 , whereas in  FIG. 3 , the inlet  201  is positioned horizontally to the outlet  202  with opposite direction. By way of different positions of the outlets  202  in each pump  2  and cooperate with different arrangement of each pump  2  in order to make the boat  9  move or turn, and thus the boat  9  turns requiring smaller radius. A remarkably feature is that through a full compression by the first and the second gear rotor  22 ,  23 , a flow of the fluid is in a positive displacement and is pressurized by the first and the second gear  22 ,  23  whereby the pump  2  generates high discharge head and therefore efficiently transports the fluid. Furthermore, the flow of the fluid generated by the pumps  2  turns to a jet-flow that the liquid is discharged uniformly during the meshing rotation of the first and second gears and thus can prevent from generating unnecessary vortex to affect the boat  9  thereby can reduce a loss of the power transmission. 
   Referring to  FIG. 4 , the transmission apparatus  4  is driven by the motive power  90  and pivotally connected to each of the pumps  2  for transmitting power at a steady speed or a discrepant speed in order to drive each of the pumps to generate the thrust of the boat  9 . The transmission apparatus  4  includes a bevel gear set  40  and four gear sets  41 ,  42 ,  43 ,  44 , wherein the bevel gear set  40  is pivotally mounted to the motive power  90  and driven by the motive power  90 . The bevel gear set  40  is further coupled with two driving shafts  901 ,  902  respectively at different sides thereof for transmitting the power to each of the four gear sets  41 ,  42 ,  43 ,  44 . Each gear set  41 ,  42 ,  43 ,  44  is respectively coupled with driven spindles  410 ,  420 ,  430 ,  440  in series. The driven spindles  410 ,  420 ,  430 ,  440  are respectively connected to the first gear rotor  22  of each pump  2  thereby to drive the second gear rotor  23  as the first gear rotor  22  is rotating. Therefore, the transmission apparatus  4  can transmit the power from the motive power  90  to far portions of the boat  9  and cooperate with the controlling panel  3  can drive each pump  2  optionally. Alternatively, the transmission apparatus  4  of the present invention is adoptable with different assembly, by way of example, it can cooperate with clutch or add a gear sets to change the direction of transmission, or add a motive power or other power plant to increase the transmission. 
   Referring to  FIGS. 5 to 10 , the four pumps  2  are mounted on a bottom of the boat  9 , wherein two of the pumps are mounted respectively on the fore part and the aft part of the boat  9 , which are equipped with the inlet  201  and the outlet  202  being horizontal to each other, wherein the outlet  202  of the fore pump  201  is positioned toward the front side of the boat  9  whereas the outlet  202  of the aft pump  201  is positioned toward the stern side of the boat  9 . The rest of the two pumps  201  are mounted respectively on the left and the right side of the boat  9  and both are equipped with the inlet  201  and the outlet  202  being perpendicular to each other. The left pump  201  is positioned close to a mid-part of the boat  9  (preferably positioned over the mid-part of the boat  9  for turning quickly). With respect to  FIGS. 6 to 10  is shown the boat  9  can move in different directions only by pressing the forward button  30 , the backward button  31 , the turning left button  32 , the turning right button  33  or the turning around button  34 ,  35 . For example, a user can press the forward button  30  for moving forwardly, or press the forward button  30  and the turning left button  32  for turning the boat  9  (as shown in  FIG. 8 ). 
   Referring to  FIGS. 11 to 13 , an alternate embodiment of a boat propulsion system  1  is illustrated, a boat  9  having three driving motors  8  (replaceable by other motive power) which drive three pumps respectively (not shown). The three driving motors  8  are arranged in a triangular position. The pumps mounted on the left and the right sides of the boat are close to mid-part of the boat and outlets of the two pumps are positioned respectively toward the left and the right side. The other pump is mounted aft and an outlet thereof is positioned at a stem side of the boat. By way of controlling the rotation speed and rotation direction of each of the motors  8  through a controlling panel and cooperate with multiple inlets and outlets which are positioned at different directions, the boat can move and turn under controlling. With further reference to  FIG. 11  illustrates the boat moving forwardly or backwardly;  FIG. 12  illustrates the boat turning rightward;  FIG. 13  illustrates the boat turning leftward. 
   While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as -well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.