Abstract:
A marine propeller with an adjustable exhaust structure is disclosed. Each adjustable exhaust device of the adjustable exhaust structure includes an exhaust hole unit with exhaust through holes cut through the outer surface and inner surface of the propeller hub of the marine propeller, an adjustment member with shielding portions mounted in the exhaust hole unit, and a fastening member for securing the adjustment member in position. The adjustment member is movable to adjust the shielding area of the shielding portions relative to the exhaust through holes when disengaged from the constraint of the fastening member. Thus, the exhaust volume is adjustable to fit different conditions without changing any component parts of the marine propeller, facilitating ease of use of the marine propeller.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention The present invention relates to marine propellers and more particularly, to a marine propeller with an adjustable exhaust structure for allowing adjustment of exhaust volume. 
         [0002]    2. Description of the Related Art 
         [0003]    U.S. Pat. No. 5,916,003 discloses a propeller device, which comprises a propeller body with a propeller hub having  4  propeller blades extending therefrom and an aperture on each propeller blade, and a plug having a diametric profile shaped to be received and retained within each aperture. The vent plugs are provided with openings therethrough so that fluids can flow from a passage within a hub of the propeller device to a region proximate the outer cylindrical surface of the hub. The plugs can be changed to modify the size of the ventilation aperture without having to change the propeller device itself. 
         [0004]    The propeller device is driven by an engine to move the propeller blades through water, achieving propeller thrust and forcing the boat to move forwards. At the same time, waste engine gas enters the passage of the propeller hub. At this time, a part of waste engine gas is exhausted through the ventilation aperture. Thus, the ventilation apertures of the plugs assist lowering the internal air pressure of the passage of the propeller hub, reducing water pressure from the propeller blades and enhancing propelling speed of the propeller blades. 
         [0005]    However, under different application conditions, such as water level, load, temperatures, and etc., the user must selectively use different sizes of plugs having different dimensions of ventilation apertures, or plugs without any ventilation aperture to adjust the exhaust volume of the propeller device to an optimal condition for better propeller performance. 
         [0006]    On other words, the user must prepare many different plugs having different dimensions of ventilation apertures. Preparing a large number of plugs relatively increases the cost. Further, the plugs may be missed easily when not in use. Therefore, the aforesaid prior art design of propeller device is not convenient to use. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a marine propeller, which allows convenient adjustment of the exhaust volume without changing any component parts, facilitating ease of use. 
         [0008]    To achieve this and other objects of the present invention, a marine propeller comprises a propeller body. The propeller body comprises a propeller hub and a plurality of propeller blades. The propeller hub comprises an outer surface and an inner surface. The propeller blades are extended outwardly from the outer surface of the propeller hub. The marine propeller further comprises at least one adjustable exhaust device. Each adjustable exhaust device comprises an exhaust hole unit cut through the outer surface and inner surface of the propeller hub, an adjustment member mounted in the exhaust hole unit, and fastening means for securing the adjustment member to the exhaust hole unit in position. The exhaust hole unit comprises at least one exhaust through hole. The adjustment member comprises at least one shielding portion for shielding the at least one exhaust through hole. Further, before the adjustment member is secured in position by the fastening means, the adjustment member is movable relative to the exhaust hole unit to adjust the shielding area of the at least one shielding portion relative to the at least one exhaust through hole. 
         [0009]    Thus, under different application conditions, the user can adjust the exhaust volume to the optimal status without changing any component parts of the marine propeller, enabling the marine propeller to provide a proper speed. Thus, the marine propeller is very convenient to use. 
         [0010]    Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an elevational view of a marine propeller with an adjustable exhaust structure in accordance with a first embodiment of the present invention. 
           [0012]      FIG. 2  is an exploded view of the marine propeller with an adjustable exhaust structure in accordance with the first embodiment of the present invention. 
           [0013]      FIG. 3  is a side view of the first embodiment of the present invention, illustrating one exhaust hole unit in the propeller body of the marine propeller. 
           [0014]      FIG. 4  is an enlarged view of a part of  FIG. 3 , illustrating one adjustment member installed in the exhaust hole unit. 
           [0015]      FIG. 5  is an end view of the adjustment member shown in  FIG. 4 . 
           [0016]      FIG. 6  is a side view of the adjustment member shown in  FIG. 4 . 
           [0017]      FIG. 7  is a sectional view of e marine propeller with an adjustable exhaust structure in accordance with the first embodiment of the present invention. 
           [0018]      FIG. 8  is similar to  FIG. 4  but showing the angular position of the adjustment member adjusted relative to the exhaust hole unit. 
           [0019]      FIG. 9  is similar to  FIG. 4  but showing the angular position of the adjustment member adjusted relative to the exhaust hole unit. 
           [0020]      FIG. 10  is a side view of a marine propeller with an adjustable exhaust structure in accordance with a second embodiment of the present invention, illustrating one exhaust hole unit in a propeller body. 
           [0021]      FIG. 11  is a sectional view of the marine propeller with an adjustable exhaust structure in accordance with the second embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to  FIGS. 1-3 , a marine propeller in accordance with a first embodiment of the present invention is shown. The marine propeller  10  comprises a propeller body  20 , three adjustable exhaust devices  30 . Each adjustable exhaust device  30  comprises, installed in the propeller body  20 , an exhaust hole unit  40 , an adjustment member  50 , and a fastening member  60 . 
         [0023]    The propeller body  20  comprises a propeller hub  22 , and three propeller blades  24 . The propeller hub  22  comprises an outer tube  222  and an inner tube  224  integrally formed of multiple rib plates (not shown), and an outer surface  226  and an inner surface  228  located on the outer tube  222 . The propeller blades  24  are outwardly extended from the outer surface  226  of the propeller hub  22 . The adjustable exhaust devices  30  are respectively disposed between each two adjacent propeller blades  24 . 
         [0024]    Referring to  FIG. 4  and  FIGS. 2 and 3  again, each exhaust hole unit  40  comprises a recess  42 , an axle hole  44 , and six exhaust through holes  46 . The recess  42  is located on the outer surface  226  comprises a bottom wall  422 , an inner peripheral wall  424 , and two blocks  426  protruded from the inner peripheral wall  424 . The axle hole  44  and the exhaust through holes  46  extend through the bottom wall  422  of the recess  42  and the inner surface  228  of the propeller hub  22 . Further, the exhaust through holes  46  are spaced around the axle hole  44 . 
         [0025]    Referring to  FIGS. 5 and 6 , each adjustment member  50  comprises a shaft  52 , and an adjustment wheel  54  formed integral with one end of the shaft  52 . The shaft  52  comprises a groove  522  extending around the periphery thereof. The adjustment wheel  54  is shaped like a gearwheel, comprising a circular peripheral wall  542 , and a plurality of notches  544  arranged around a circle, i.e., equiangularly spaced around the circular peripheral wall  542 . The adjustment wheel  54  further comprises six through holes  546  cut through the opposing top and bottom sides thereof and spaced around the shaft  52 , and a shielding portion  548  between each two adjacent through holes  546 . 
         [0026]    Referring to  FIG. 7  and  FIGS. 2 and 4  again, in each adjustable exhaust device  30 , the shaft  52  of the adjustment member  50  is inserted into the axle hole  44  of the exhaust hole unit  40 , the adjustment wheel  54  of the adjustment member  50  is set in the recess  42  of the exhaust hole unit  40 , and the two blocks  426  of the recess  42  are respectively engaged into one respective notch  544  of the adjustment wheel  54 . The fastening member  60  is a C-shaped retaining ring mounted in the groove  522  of the shaft  52  of the adjustment member  50  to secure the adjustment member  50  to the exhaust hole unit  40 . The user can detach the fastening member  60 , and then remove the adjustment wheel  54  of the adjustment member  50  out of the recess  42 , and then rotate the adjustment member  50  to the desired angle, and then set the adjustment wheel  54  of the adjustment member  50  in the recess  42  again, and thus the shielding portions  548  of the adjustment wheel  54  of the adjustment member  50  are moved relative to the exhaust through holes  46  to change their shielding area relative to the exhaust through holes  46  and to further adjust the exhaust volume of the marine propeller  10 . 
         [0027]    For example, in the configuration shown in  FIG. 8 , the shielding portions  548  of the adjustment wheel  54  of the adjustment member  50  are moved away from the exhaust through holes  46  of the exhaust hole unit  40  and the exhaust through holes  46  of the exhaust hole unit  40  are fully opened. At this time, the exhaust volume of the marine propeller  10  reaches the maximum level. In the configuration shown in  FIG. 9 , the exhaust through holes  46  of the exhaust hole unit  40  are fully shielded by the shielding portions  548  of the adjustment wheel  54  of the adjustment member  50 , and the internal gas of the propeller hub  22  cannot be exhausted. At this time, the exhaust volume of the marine propeller  10  reaches the minimum level. Further, the shielding portions  548  of the adjustment wheel  54  of the adjustment member  50  can be moved to a position to partially shield the exhaust through holes  46  of the exhaust hole unit  40 , as shown in  FIG. 4 . Subject to the aforesaid operation of rotating the adjustment member  50  relative to the exhaust hole unit  40 , the shielded area of the exhaust through holes  46  of the exhaust hole unit  40  is relatively adjusted. 
         [0028]    In other words, under different application conditions, the user can adjust the exhaust volume to the optimal status without changing any component parts of the marine propeller  10 , enabling the marine propeller  10  to provide a proper speed. Thus, the marine propeller  10  is very convenient to use. 
         [0029]    It is to be noted that in each of the aforesaid adjustable exhaust devices  30 , the fastening member  60  is not limited to C-shaped retaining ring, and any of a variety of other fastening means capable of prohibiting the adjustment member  50  from escaping out of the exhaust hole unit  40  and allowing movement of the shielding portions  548  of the adjustment wheel  54  of the adjustment member  50  relative to the exhaust through holes  46  of the exhaust hole unit  40  before fixation can be used as a substitute. Further, the number and locations of the blocks  426  of the recess  42  of each exhaust hole unit  40  may be changed without departing from the spirit and scope of the invention. One single block  426  can also achieve the same effect of securing the adjustment member  50  in position. 
         [0030]    In the aforesaid first embodiment, the relative positioning between the exhaust hole unit  40  and the respective adjustment member  50  and quantitative adjustment of the relative angle therebetween are achieved by means of selectively engaging the relative smaller number of the blocks  426  of the exhaust hole unit  40  into the relatively larger number of the notches  544  of the adjustment member  50 . Alternatively, the adjustment member  50  can be made having a relatively smaller number of blocks for selectively engaging a larger number of notches in the exhaust hole unit  40 . Further, it is not a limitation to arrange the notches around a circle. 
         [0031]    Further, the number and arrangement of the exhaust through holes  46  of the exhaust hole unit  40  and the number and arrangement of the through holes  546  and shielding portions  548  of each adjustment member  50  are not limited to the aforesaid design. Actually, each adjustable exhaust device  30  can be made having at least one set of exhaust through holes  46 , through holes  546  and shielding portions  548  to achieve the same effects. 
         [0032]    Further, the marine propeller  10  can be made having at least one adjustable exhaust device  30  to achieve the aforesaid exhaust volume adjustment effect. However, arranging one adjustable exhaust device  30  between each two adjacent propeller blades  24  can balance the resistance of the propeller blades  24 , facilitating smooth operation of the marine propeller  10 . 
         [0033]    In the aforesaid first embodiment, the recess  42 , axle hole  44  and exhaust through holes  46  of the exhaust hole unit  40  are located on the propeller body  20 , however, this arrangement is not a limitation. In a second embodiment of the present invention as shown in  FIGS. 10 and 11 , the exhaust hole unit  70  of the marine propeller comprises a through hole  72  extending through the outer surface  226  and inner surface  228  of the propeller hub  22  of the propeller body  20 , and a plug  74  fixedly mounted in the through hole  72 . The plug  72  defines an axle hole  742 , and a plurality of exhaust through holes  744 . Thus, this exhaust hole unit  70  achieves the same effects as the exhaust hole unit  40  of the aforesaid first embodiment. 
         [0034]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.