Abstract:
A weed deflector for a water intake formed in the lower unit of an outboard motor or stern drive of an inboard outboard engine. The weed deflector includes a fin with a leading edge disposed between a fin base and a tip. A mounting plate fixes the fin base to the lower unit (or stern drive) up flow of the water intake in either a horizontal or vertical orientation. The cross sectional form of the fin induces turbulence in the water flow adjacent to the water intake thereby reducing the ability of debris from obstructing the water intake.

Description:
TECHNICAL FIELD 
   The present invention relates generally to outboard motors. More specifically the present invention relates to weed deflectors that eliminate or at least reduce the amount of weeds and debris that can obstruct an outboard motor&#39;s water intake(s). 
   BACKGROUND ART 
   There exist a number of guards for outboard motors and the lower units of inboard/outboard engines that disclose a variety of means to keep its spinning propeller(s) from coming in contact with objects in the water (like swimmers or debris), and even sub-aquatic features (like rocks and shoals). Typically a wire basket arrangement fixed to the lower portion of the motor enshrouds the propeller. A good example of such a guard is disclosed in U.S. Pat. No. 5,928,042 attributed to Quiggins entitled Propeller Guard (hereinafter Quiggins &#39;042). Additional examples are U.S. Pat. No. 5,44,346 attributed to Griffin entitled Driveshaft Housing Attachment (hereinafter Griffin &#39;346); U.S. Pat. No. 4,832,634 attributed to Kearns entitled Flow Control Device and Protector Device For An Outboard Motor (hereinafter Kearns &#39;634); U.S. Pat. No. 4,078,516 attributed to Balius entitled Propeller Guard (hereinafter Balius &#39;516); U.S. Pat. No. 4,070,984 attributed to Kappas entitled Outboard Motor and Weed Guard Therefore (hereinafter Kappas &#39;984); and U.S. Pat. No. 4,013,033 attributed to Porter et al entitled Weed Guard for Trolling Motors (hereinafter Porter &#39;033). 
   Other propeller guards incorporate a cutter to cleave debris into smaller portions that are in turn deflected away from the spinning propeller by a plurality of fingers. A good example of such a guard is disclosed in U.S. Pat. No. 2,355,842 attributed to Arado entitled Combined Cutter, Distributor and protector for Outboard Motors (hereinafter Arado &#39;842). 
   Protecting the propeller is also achieved by fitting a striker up flow of the outboard motor&#39;s lower unit. When debris or a submerged obstruction comes in contact with the striker, the lower unit is temporarily pivoted up thereby removing the spinning propeller from the debris or obstruction. Such examples are disclosed in U.S. Pat. No. 6,179,673 attributed to Leroux entitled Outboard Motor Protection Apparatus (hereinafter Leroux &#39;673) and U.S. Pat. No. 5,664,977 attributed to Dinkowitz et al entitled Boat Propeller Sled (hereinafter Dinkowitz &#39;977); and U.S. Pat. No. 5,178,565 attributed to Jacobson entitled Lower Unit Guard (hereinafter Jacobson &#39;565). All of the propeller guards disclosed above do not provide any protection for the motor&#39;s water intake(s) from debris. 
   The typical water intake for an outboard motor is fitted with a screen, strainer or grate to keep waterborne debris from being ingested by the motor&#39;s water pump. However, debris can become clogged or lodged in such a screen or strainer, which in turn reduces the flow of cooling water to the motor. Reducing the flow of cooling water can reduce the work life of or at least increase the wear and tear on the motor. 
   Aside from screens and strainers, a variety of rods or fins positioned over or in the water inlet have been used to prevent clogging of the strainer (if fitted) or the inlet itself. The rods or fins are positioned over (or in the inlet) in such a manner to deflect debris away from an inlet as water flows around the rods or fins. Examples of such arrangement are disclosed in U.S. Pat. No. 3,147,733 attributed to Engel for an Inlet Screen (hereinafter Engel &#39;733); U.S. Pat. No. 3,446,177 attributed to Thornburg et al for a Water Jet Propulsion Apparatus (hereinafter Thornburg &#39;177); U.S. Pat. No. 5,468,165 attributed to Weber et al for Grass and Debris Exclusion Plate for Marine Jet Pumps (hereinafter Weber &#39;165); and U.S. Pat. No. 5,577,941 attributed to Chartier for Marine Jet Drive Weed Grate (hereinafter Chartier &#39;941). Each of these devices obstructs the intake not unlike the debris it attempts to clear. Such obstructing debris deflectors require a larger inlet opening for new construction. Such obstructing debris deflectors fitted on existing water inlets restrict water flow causing reduced cooling and increased motor wear. Furthermore, such obstructing deflectors require a custom fit into or over the inlet in order to work properly. 
   In view of the above described deficiencies and issues associated with existing deflectors, the present invention has been developed to alleviate these drawbacks and provide further benefits to the user. These enhancements and benefits are described in greater detail herein below with respect to several alternative embodiments of the present invention. 
   SUMMARY OF INVENTION 
   The present invention in its several disclosed embodiments alleviates the drawbacks and deficiencies described above with respect to conventional water intake debris deflectors. The present invention incorporates several additionally beneficial features. 
   The improved water intake debris deflector includes a fin positioned up flow to a water intake located in the lower unit of an outboard motor (or inboard outboard stern drive). The leading edge of the fin is angled in such a manner as to push debris down and away from a water inlet. Furthermore, the fin&#39;s length and thickness causes small amounts of turbulence in the water flow adjacent to a water intake and propeller. Disrupting the laminar flow of the water adjacent to the water intake reduces the ability of debris to become trapped over the water inlet. Furthermore, disrupting the laminar flow of the water adjacent to a propeller decreases the likelihood of propeller cavitation. 
   The improved debris deflector may further include a limiting bracket that prevents excessive fin waiver. Excessive fin waiver can cause the misdirection of water away from an inlet, cavitation bubbles (in extreme cases) or even fin failure. 
   It is the general object of the present weed deflecting invention to provide a low maintenance passive weed deflector for water inlets formed in lower units of outboard motors or inboard outboard stern drives. 
   It is another object of the present invention to provide a weed-deflecting device capable of being easily fitted to existing lower units of outboard motors or inboard outboard stern drives. 
   It is a further object of the present invention to provide a weed-deflecting device capable of disrupting the laminar flow of water in the region of a water intake to reduce debris obstruction. 
   It is still another object of the present invention to provide a weed-deflecting device capable of disrupting the laminar flow of water in the region of a propeller to reduce cavitation. 
   It is yet another object of the present invention to provide a weed deflecting device which does not obstruct or occlude a water intake opening formed in the lower unit of an outboard motor or inboard outboard stern drive. 

   
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     The invention is described in greater detail in the following examples and with reference to the attached drawings, in which: 
       FIG. 1  is an elevation view of an improved weed deflector fixed vertically to an outboard motor&#39;s lower unit. 
       FIG. 2  is a perspective view of an improved weed deflector fixed vertically to an outboard motor&#39;s lower unit. 
       FIG. 3  is an elevation view of an improved weed deflector fixed horizontally to a stern drive of an inboard outboard engine. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   General Overview 
   As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale, some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and function details disclosed herein are not be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ in the present invention. 
   The present invention is directed toward a weed deflector  10  that includes at least one fin  11  with a leading edge  15  disposed between a fin base  13  and a tip  17 . A mounting plate  20  is configured to fix fin base  13  to a lower unit  01  of an outboard motor (or stern drive of an inboard outboard engine  01 ) (See  FIGS. 1 and 3 ). In a preferred embodiment, fin  11  is fixed in a vertical orientation to a cavitation plate  05  by a mounting plate  20  (See  FIG. 1 ). In another preferred embodiment, a fin  11  is fixed horizontally to a stern drive  01  by a mounting plate  20  (See  FIG. 3 ). In either orientation, at least a portion of leading edge  15  extends across a portion of the water flow that moves adjacent to at least a portion of water inlet  07  (See  FIGS. 1 and 3 ). 
   In a preferred embodiment, the width of fin  11  tapers from base  13  to tip  17 . Such tapering provides the necessary cant or sweep to the leading edge  15  to direct debris away from water inlet  07  and towards tip  17 . It is contemplated that the width of fin base  13  may extend beyond mounting base plate  15  (See  FIG. 2 ). In an alternative embodiment, the width of fin base  13  is equal to or less than the width of mounting base plate  15  (not shown). Tip  17  can be terminated at any distance from base  13 . With a fin  11  in a vertical orientation, the preferred location of tip  17  is just above skeg  09  (See  FIG. 1 ). With a fin  11  in a horizontal orientation, the preferred location of tip  17  is no further than the tips of the propeller  03  (not shown). Such a preferred configurations allows debris to be push away from propeller  03 . Tip  17  can be pointed, curved or truncated. 
   In another embodiment, leading edge  15  bows out in a curved fashion between fin base  13  and tip  17  (not shown). In such a configuration, leading edge  15  directs debris suspended in a water flow away from the water inlet  07 . While a majority of the debris will be directed towards a tip  17 , some debris can be pushed up toward base  13 . 
   It is contemplated that fin  11  and mounting base plate  15  are constructed from metals, composite materials and/or a combination of both with sufficient characteristics to be wear resistant, withstand debris strikes and oscillations without significant fatigue. It has been determined that a fin  11  with a length between about 2 inches to about 24 inches from base  13  to tip  17  with a cross sectional thickness between about 0.001 inches to about 3 inches and a leading edge cant between about 1 degree and about 80 degrees off a longitudinal axis running the length of a fin  11  causes debris to be deflected from an adjacent water inlet  07 ; and further encourages water turbulence around an adjacent water intake and propeller. The cross sectional shape of fin  11  can be elliptical, oval, circular, arcuate, square, polygonal, rectangular and/or a combination thereof. 
   In one embodiment, fin  11  is constructed from stainless steel (or aluminum) plate with a thickness of about one sixteenth of an inch; a base  13  to tip  17  length of approximately nine to twelve inches and a leading edge cant of about 78 degrees off a longitudinal axis. Such a fin  11  is welded to mounting base plate  13 . Once mounted in a vertical orientation to a cavitation plate  05 , fin  11  directs water borne debris down along leading edge  15  and away from water inlet  07 . Furthermore a rectangular cross section of fin  11  creates turbulence within the water that flows adjacent to a water inlet  07  and propeller  03 . Such fin-induced turbulence prevents or at least reduces the likelihood of waterborne debris from clogging a water inlet  07 . Another benefit of such fin-induced turbulence is the reduction of propeller  03  cavitation during take-offs. 
   In a preferred embodiment, fin  11  as described above is fitted with a set of limiting brackets  19  near tip  17 . Limiting brackets  19  extend away from fin  11  and toward outboard motor lower unit  01  (See  FIG. 2 ). If fin  11  begins to oscillate (side to side and/or twist) within a flow of water, limiting brackets  19  come in contact with outboard motor lower unit  01  to restrain the movement. Limiting brackets  19  prevent excessive fin oscillations. Excessive fin oscillations can cause the misdirection of water away from an inlet, the creation of cavitation bubbles (in extreme cases) or even fin failure. In another embodiment, limiting brackets  19  are mounted to outboard motor lower unit  01  (rather than fin  11 ) and extend toward fin  11  (Not shown). If fin  11  begins to oscillate (as described above), limiting brackets  19  come in contact with fin  11  to prevent further movement. 
   In a preferred horizontal orientation of the deflector, a number of fins  11 , are positioned horizontally across water inlet  07  (See  FIG. 3 ). The length of a fin between base  13  and tip  17  is about 2 inches with a leading edge  15  cant of about 70 degrees and an arcuate cross sectional shape with a thickness of about ¼ of an inch to promote turbulence around water inlet  07 . It is further contemplated that tip  17  is rounded. 
   A weed deflector  10  and its components have been described herein. These and other variations, which will be appreciated by those skilled in the art, are within the intended scope of this invention as claimed below. As previously stated, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various forms.