Patent Publication Number: US-6986689-B2

Title: System and apparatus for improving safety and thrust from a hydro-drive device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to marine propulsion devices such as outboard motors, stern drive units and the like, and more particularly relates to improving safety and hydro-flow thrust from hydro-drive devices. 
   2. Description of the Related Art 
   For over 100 years screwdriven propellers and impellers have been used to propel marine vehicles. Over the years, the technology of the propulsion drives has changed incredibly. However, the technology of the propeller/impeller, aside from sizes and shapes, has remained relatively unchanged. 
   As a propeller/impeller turns, water is drawn in and is accelerated through the fly wheel action of a propeller/impeller increasing the higher-velocity stream of water behind (aft) the propeller/impeller. Accelerating the water by the action of pulling water in and pushing water out at a higher velocity is commonly known as adding momentum to the water. This change in momentum or acceleration of the water (hydro-flow) results in a force called “thrust.” A curvature of the propeller/impeller blade creates low-pressure on the back of the blade, thus inducing lift, much like the wing on an airplane. With a marine propeller/impeller, the lift is translated into horizontal movement. 
   The spinning blades of the propeller/impeller produce hydro-flow thrust, which can depend upon many factors. Examples of such factors include volume of water accelerated per time unit, propeller/impeller diameter, velocity of incoming hydro-flow, density of water, and the SHP (shaft horsepower) accelerating the propeller/impeller. As in any motorized industry, great expense and effort is put into the improvement of efficiency and power of the motor. Perhaps the largest factor relating to efficiency and power or hydro-flow thrust is the propeller/impeller. 
   The propeller shroud also has the additional benefit of protecting submerged objects from contact with the propeller/impeller. With ever increasing marine vehicle ownership, incidents of injury or damage due to propeller/impellers strikes, though unfortunate, seem commonplace. The shroud prevents swimmers, water skiers, water sports enthusiast, sea and marine life from encountering or being entangled by the spinning blades of a propeller/impeller. Safety is accomplished by enclosing the entire fly wheel area of the propeller/impeller within the propeller shroud. 
   Shrouds are available that may perform the function of protecting people, marine sea and plant life from the propeller/impeller. However, available shrouds tend to restrict water flow, increase drag, or modify the exiting water stream. Each of the aforementioned actions appreciably reduces hydro-flow thrust, thus negatively affecting the performance. 
   From the foregoing discussion, it should be apparent that a need exists for a system and apparatus that protects people, marine sea and plant life, and increases hydro-flow thrust generated from a boat propeller/impeller. Beneficially, such a system and apparatus would increase hydro-flow, decrease drag, would improve performance by increasing the volume and velocity of hydro-flow thrust in a vortex exiting the shroud. 
   SUMMARY OF THE INVENTION 
   The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available hydro-drive device thrust enhancement systems. Accordingly, the present invention has been developed to provide a system and apparatus for improving thrust from a hydro-drive device that overcome many or all of the above-discussed shortcomings in the art. 
   The apparatus to improve thrust may include a shroud having a first opening for the ingress of water, and a second opening for the egress of water, and a vane extending inward from an interior surface of the shroud. The vane is configured to direct water to form a vortex that exits the shroud. In a further embodiment, the vane comprises a planar region directly attached to an interior surface of the shroud and a curved region configured to change curvature in response to increasing or decreasing thrust from the hydro-drive device. 
   The vane may be formed of a material having a tension configured to allow the curvature of the vane to change in response to the thrust of the hydro-drive device and configured to return to an original configuration. In one embodiment, the apparatus may include a spring tension bar having a first end coupled to the interior surface and a second end removably coupled to a paddle. The paddle is configured to adjust the diameter of the second opening in response to thrust from the hydro-drive device, and may have the vane directly connected to a surface of the paddle. 
   In a further embodiment, the apparatus is configured having a plurality of vanes extending toward the interior of the shroud, each vane configured to direct water to form a vortex that exits the shroud. The shroud may include a mounting plate coupled to an outside surface of the shroud. The mounting plate is configured to couple the shroud to a vehicle. The shroud may be configured to at least partially enclose the hydro-drive device. 
   A system for improving thrust is also provided. The system may include a motor, a hydro-drive device coupled to the motor, a shroud having a first opening configured to intake water, and a second opening configured to exhaust water, and a vane extending inward from an interior surface of the shroud. The vane is configured to direct water to form a vortex that exits the shroud. 
   In an alternative embodiment, the apparatus may include a shroud having a first opening for the ingress of water, and a second opening for the egress of water and a vane extending inward from an interior surface of the shroud. The vane is configured to direct water to form a vortex that exits the shroud, and comprises a planar region directly attached to an interior surface of the shroud and a curved region configured to change curvature in response to increasing or decreasing thrust from the hydro-drive device. 
   Alternatively, the apparatus may comprise a shroud having a first opening for the ingress of water, and a second opening for the egress of water, and a vane extending inward from an interior surface of the shroud. The vane is configured to direct water to form a vortex that exits the shroud. A spring tension bar is also provided and has a first end coupled to the interior surface and a second end removably coupled to a paddle. The paddle may be configured to adjust the diameter of the second opening in response to thrust from the hydro-drive device. 
   Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
   Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
   These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
       FIG. 1  is a schematic block diagram illustrating one embodiment of a system for moving a marine vehicle in accordance with the prior art; 
       FIG. 2  is a schematic block diagram illustrating one embodiment of a system for moving a marine vehicle in accordance with the present invention; 
       FIG. 3  is a perspective view illustrating one embodiment of a shroud in accordance with the present invention; 
       FIG. 4   a  is a perspective view illustrating one embodiment of a shroud in accordance with the present invention; 
       FIG. 4   b  is a front view of the shroud of  FIG. 4   a;    
       FIG. 5   a  is a perspective view illustrating one embodiment of a vane in accordance with the present invention; 
       FIG. 5   b  is a side view of the vane of  FIG. 5   a;    
       FIG. 6  is a front view of one embodiment of a shroud in accordance with the present invention; 
       FIG. 7   a  is side view of one embodiment of a paddle in accordance with the present invention; 
       FIG. 7   b  is a perspective view of the paddle of  FIG. 7   a;    
       FIG. 7   c  is a perspective view of one embodiment of a spring tension bar in accordance with the present invention; 
       FIG. 8   a  is a perspective view of one embodiment of a mounting plate in accordance with the present invention; 
       FIG. 8   b  is a bottom view of one embodiment of a skeg coupler in accordance with the present invention; 
       FIG. 9   a  is a schematic side view of one embodiment of a telescoping shroud in accordance with the present invention; 
       FIG. 9   b  is a side view of a further embodiment of a telescoping shroud in accordance with the present invention; 
       FIG. 10   a  is a side view of another embodiment of a telescoping shroud in accordance with the present invention; 
       FIG. 10   b  is a perspective view of one embodiment of interior surfaces of a telescoping shroud in accordance with the present invention; and 
       FIG. 11  is a perspective view of one embodiment of a shroud for trolling motors in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
   Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are given to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     FIG. 1  is a side view of one embodiment of a system  100  for moving a marine vehicle in accordance with the prior art. The system  100  may include a transom mount assembly  102  for connecting the system  100  to a stern or transom of a boat (not shown). The transom mount assembly  102  is configured to transfer power from a motor to an upper gear case assembly  104 . The upper gear case assembly  104  directs the power through a drive shaft (not shown) to the lower unit  106  and in turn to a hydro-drive device  108 . The system  100  may also include a skeg  110  and a cavitation plate  112  (also referred to as “anticavitation plate” or “antiventillation plate”). The cavitation plate  112  prevents surface air from reaching the hydro-drive device  108 . 
     FIG. 2  is a schematic block diagram graphically illustrating one embodiment of a system  200  for moving a marine vehicle in accordance with the present invention. The system  200  may include the stern of the boat  202  connected to the transom mount assembly  102  as described above with reference to  FIG. 1 . Additionally, the system  200  may comprise a shroud  204  configured to at least partially enclose the hydro-drive device. In one embodiment, the shroud  204  is coupled to the cavitation plate  112  and the skeg  110 . 
   The depicted embodiment illustrates the shroud  204  coupled to a stern-drive system. Alternatively, the shroud  204  may be similarly coupled to outboard motor assemblies, inboard motor assemblies, jet propelled vehicles such as personal water craft, and other marine drive assemblies having hydro-drive devices  108 . As used herein, the term “hydro-drive device” means any marine vehicle thrust inducing device such as, but not limited to, propellers, impellers, and the like. 
   The system  200  is configured to enable the boat  202  to move about in water. The boat  202  may move in both a forward direction represented by arrow  206  and a reverse direction. The gear case assembly  104  is mounted for pivotal movement about a horizontal axis to enable the boat to turn. As the boat  202  moves through water, water enters the shroud  204  in a direction illustrated by arrows  208  and exits in a direction indicated by arrows  210 . The shroud  204  may comprise a first opening  302  (shown in  FIG. 3 ) configured to allow the unrestricted ingress of water, and a second opening  304  (shown in  FIG. 3 ) for the egress of water. 
     FIG. 3  is a perspective view shown from the top and to one side and illustrating one embodiment of the shroud  204  in accordance with the present invention. The shroud  204  may comprise a substantially tubular cylinder having the first opening  302  and the second opening  304 . The shroud  204  is configured to at least partially circumferentially enclose the hydro-drive device  108  in a cylindrical region  306 . The first opening  302  may have a diameter slightly larger than the hydro-drive device  108  in order to circumferentially enclose the hydro-drive device. The cylindrical region  306  may alternatively completely circumferentially enclose the hydro-drive device  108  thereby protecting swimmers, water skiers, water sports enthusiast, and sea and marine life from encountering or being entangled by the hydro-drive device  108 . 
   In a further embodiment, the shroud  204  may comprise a conical region  308 . As is well known to those skilled in the art, the cylindrical region  306  together with the conical region  308  form what is known as a “Kort Nozzle.” The conical region  308  causes water flow to accelerate in order to exit through the second opening  304  with a Venturi-like effect. 
   The shroud  204  may also include a mounting plate  310  for connecting the shroud  204  to the cavitation plate  112 , and a skeg coupler  312  for securing the shroud  204  to the skeg  110 . Fastening devices (not shown) may include standard nuts and bolts. Alternatively, a keyed fastening device may be used when connecting the skeg coupler  312  to the skeg  110  in order to prevent theft of the shroud  204  and the hydro-drive device  108 . 
   The shroud  204  may be formed of a light-weight metallic based material such as, but not limited to, aluminum alloys, steel alloys, titanium alloys, or the like. Additionally, the shroud  204  may be formed of composite materials including carbon fiber, high-impact plastics, or fiberglass. Depending upon the material used, the shroud may be pressed, rolled, injection molded, thermoformed, layed-up, spun, or extruded. Different finishes may also be applied to a surface of the shroud  204  in order to reduce drag and form a protective layer. 
     FIGS. 4   a  and  4   b  graphically illustrate one embodiment of the shroud  204  having a plurality of vanes  402  for directing fluid to form a vortex  404  as the water exits the shroud. Alternatively, the shroud  204  may comprise a single vane  402  for directing fluid to form a vortex  404 . As used herein, the term “vortex” means fluid flow involving rotation about an axis. 
   In one embodiment, each vane  402  may include a planar region  406  and a curved region  408 . Alternatively, the vane  402  may be configured having only the planar region  406  or only the curved region  408 . Each vane  402  may extend inward from an interior surface of the shroud  204 , and extend longitudinally towards the second opening  304 . Additionally, the vanes  402  are preferably angled in such a way as to induce and/or enhance the vortex  404  formed by the hydro-drive device  108 . In a further embodiment, the planar region  406  of each vane is removably coupled to the interior surface  410  of the shroud. In an alternative embodiment, the vanes  402  may be configured as grooves or channels (not shown) formed in the interior surface  410  of the shroud  204  and angled to direct water to enhance the vortex  404 . 
   The curved region  408  may be free to change curvature in response to thrust produced by the hydro-drive device  108 . Alternatively, the entirety of each vane  402  may be fixedly coupled to the shroud  204 . For example, the vane  402  may be riveted, welded, bolted, attached using adhesive, or the like. As thrust increases, the vanes  402  may be configured to adjust the curvature of the curved region  408 . In one embodiment, each vane  402  is formed of a material selected to have a spring tension configured to adjust the curvature of the curved region  408  in response to the thrust or water pressure, and subsequently return to an original curved configuration. For example, as thrust increases, each vane  408  may “straighten” and effectively increase the diameter of the second opening  304 . 
     FIG. 5   a  is a perspective view of one embodiment of the vane  402  in accordance with the present invention.  FIG. 5   b  is a side view of the vane  402  of  FIG. 5   a . The vane  402  may be used in the shrouds of  FIGS. 2–4   b . The vane  402  may include an angle bracket  502  for connecting to the shroud  204 . Alternatively, the angle bracket  502  may be a separate unit or formed into the surface of the shroud  204 . In one embodiment, the vane  402  is formed of a metal such as aluminum. In a further embodiment, the vane  402  may be formed of a ceramic material, composite material, or a high-impact rigid plastic. 
   In one embodiment, the vane  402  is configured with a curve to direct water to form a vortex as described above with reference to  FIGS. 4   a  and  4   b . The vane  402  may be angled to form counter-clockwise or clockwise vortices depending upon the direction of spin of the hydro-drive device  108 . 
     FIG. 6  is a front view of one embodiment of the shroud  204  in accordance with the present invention. In the depicted embodiment, the shroud  204  comprises a plurality of paddles  602 . Each paddle  602  may be coupled to a spring tension bar  604 . The spring tension bar will be described in greater detail below with reference to  FIG. 7   c . Each paddle  602  may be configured with the vane  402 . As thrust from the hydro-drive device  108  increases, the pressure on the paddles  602  causes the spring tension bar  604  to partially collapse, thereby increasing the diameter of the second hole  304 . However, even as the diameter of the second hole  304  increases, the vanes  402  continue to direct water to form the vortex  404  as water exits the shroud  204 . 
   Referring jointly to  FIGS. 7   a  and  7   b , shown therein are perspective views taken from the top and front respectively, and graphically illustrating the paddle  602  in accordance with the present invention. In one embodiment, the paddle  602  has a substantially rectangular shape having a slot  702  for removably coupling to one end of the spring tension bar  604 . The paddle  602  may be coupled to the spring tension bar  604  using a fastening device (not shown) such as a bolt, a rivet, or the like. 
   In one embodiment, the paddle  602  has a curved profile  704  with the vane  402  extending from an inward facing surface  706 . The vane  402  may be coupled to the paddle as described above, or alternatively, the vane  402  may be formed as an integral part of the paddle. In a further embodiment, the curved profile  704  may be asymmetric such that the paddle  602  may direct water to form the vortex  404 . Additionally, the paddle  602  may be injection molded integral with the vane  402 . 
     FIG. 7   c  is a perspective view taken from the top and side and illustrates one embodiment of the spring tension bar  604  in accordance with the present invention. In the depicted embodiment, the spring tension bar  604  comprises a first end  708  configured to couple to the interior surface  410  of the shroud  204 . The spring tension bar  604  may also comprise a plurality of holes  710  for receiving fastening devices. In a further embodiment, the spring tension bar  604  includes a second end  712  for removably coupling the paddle  702 . 
   The spring tension bar  604  may be formed of a metallic based material such as an aluminum alloy, or other light weight metallic based material. Alternatively, the spring tension bar  604  may be formed of any material configured to return to an original configuration after the thrust from the hydro-drive device  108  has been removed. 
     FIG. 8   a  is a perspective view taken from the side and top and graphically illustrates one embodiment of the mounting plate  310  in accordance with the present invention. In one embodiment, the mounting plate  310  is configured to mount to the cavitation plate  112  of an outboard or stern drive motor housing. The mounting plate  310  may comprise a plurality of raised side portions  802  for engaging the cavitation plate  112  and a curved central region  804  for engaging the shroud  204 . In a further embodiment, the mounting plate  310  may engage any flat surface such as a boat bottom, thereby enabling the shroud  204  to be mounted to marine vehicles that do not employ outboard motor housings such as, but not limited to tugboats, cruise ships, ocean cargo ships, and personal water craft. In an alternative embodiment, the mounting plate  310  also includes a plurality of holes  806  for receiving fastening devices. 
     FIG. 8   b  is a top view of the skeg coupler  312  of  FIG. 3  in accordance with the present invention. In one embodiment, the skeg coupler  312  comprises a slot  808  for receiving the skeg  110  of the outboard system  100 . Alternatively, the slot  808  may receive the skeg of non-outboard marine drive systems. Once the skeg coupler  312  has been attached to the skeg  110 , a unique fastener, such as a bolt  810  with a unique key may be locked in place in order to prevent theft of the hydro-drive device  108  or the shroud  204 . 
     FIG. 9   a  is a side view of a telescoping shroud  900  in accordance with the present invention. In one embodiment, the telescoping shroud  900  comprises the mounting plate  310  and the skeg coupler  312 . The telescoping shroud  900  may also include a plurality of cylinders  902 ,  904 ,  906 , each of a different diameter. In a further embodiment, a first cylinder  902  may be coupled to the mounting plate  310  and the skeg coupler  312 . A second cylinder  904  may be fixedly coupled to the first cylinder  902 . The second cylinder  904 , may alternatively be slidably coupled to the first cylinder  902  and configured to extend with increasing pressure or thrust produced by the hydro-drive device  108 . Likewise, a third cylinder  906  may be fixedly or slidably coupled. Openings  907  between the cylinders  902 ,  904 ,  906  may allow the egress of fluid from the shroud  902 . 
     FIG. 9   b  is a side view of a further embodiment of a telescoping shroud  908  in accordance with the present invention. In the embodiment of  FIG. 9   b , the shroud  908  comprises the mounting plate  310 , the skeg coupler  312 , and the first cylinder  902 . In a further embodiment, a substantially conical cylinder  910  may be coupled to the first cylinder  902  as described above. A second conical cylinder  912  may similarly be coupled to first conical cylinder  910 . Alternatively, the telescoping shroud  908  may comprise the first cylinder  902  and the first conical cylinder  910 . As described above, the cylinders  902 ,  910 ,  912  may be either fixedly coupled or slidably coupled and have openings  907  for the egress of water. 
     FIG. 10   a  is a side view of another embodiment of a telescoping shroud  1000  having diverging conical sections in accordance with the present invention. In one embodiment, the telescoping shroud  1000  includes the mounting plate  310 , the skeg coupler  312 , and first and second diverging cylinders  1002 ,  1004 . The diverging cylinders  1002 ,  1004  when coupled to the first cylinder  902  may form openings  907  as described above for the egress of water. 
     FIG. 10   b  is a perspective view taken from the front and top and illustrates one embodiment of interior surfaces  1006  of the telescoping shrouds  900 ,  908 ,  1000 . The interior surfaces  1006  of the shroud may include a plurality of vanes  1008  extending inward and forming an intersection  1010 , which is in the depicted embodiment a cross-like configuration. In one embodiment, the shroud may have four vanes  1008 . Alternatively, the shroud may comprise any number of vanes  1008 . The vanes  1008  may be angled to direct water to form a vortex as the water exits the shroud. In a further embodiment, the vanes  1008  may be replaced by the vanes  402 . The vane  402  may be coupled to the first cylinder  902  and extend longitudinally towards the rear of the shroud  900 ,  908 ,  1000 . 
     FIG. 11  is a perspective view diagram illustrating one embodiment of a shroud  1100  suitable for use with trolling motors. In one embodiment, the shroud  1100  includes a mounting collar  1102  and a skeg collar  1104 . The mounting collar  1102  may be a clamshell-like mounting device for receiving a drive shaft (not shown) of the trolling motor. Fasteners  1106  are configured to securely maintain the position of the shroud  1100  relative to the drive shaft. The skeg collar  1104  may be coupled to an inside surface  1108  of the shroud  1100 , or alternatively to an outside surface  1110  of the shroud  1100 . The skeg collar  1104  is configured to slidably receive a skeg (not shown) of the trolling motor. The shroud  1100  may implement the plurality of vanes  402  as described with reference to  FIGS. 4–7  or alternatively the cross-like vanes  1008  configuration of  FIG. 10   b.    
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.